git.sesse.net Git - movit/blob - effect_chain.cpp

   1 #define GL_GLEXT_PROTOTYPES 1
   2
   3 #include <GL/glew.h>
   4 #include <assert.h>
   5 #include <locale.h>
   6 #include <math.h>
   7 #include <stddef.h>
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <string.h>
  11 #include <algorithm>
  12 #include <set>
  13 #include <stack>
  14 #include <vector>
  15
  16 #include "alpha_division_effect.h"
  17 #include "alpha_multiplication_effect.h"
  18 #include "colorspace_conversion_effect.h"
  19 #include "dither_effect.h"
  20 #include "effect.h"
  21 #include "effect_chain.h"
  22 #include "gamma_compression_effect.h"
  23 #include "gamma_expansion_effect.h"
  24 #include "init.h"
  25 #include "input.h"
  26 #include "util.h"
  27
  28 EffectChain::EffectChain(float aspect_nom, float aspect_denom)
  29         : aspect_nom(aspect_nom),
  30           aspect_denom(aspect_denom),
  31           dither_effect(NULL),
  32           fbo(0),
  33           num_dither_bits(0),
  34           finalized(false) {}
  35
  36 EffectChain::~EffectChain()
  37 {
  38         for (unsigned i = 0; i < nodes.size(); ++i) {
  39                 if (nodes[i]->output_texture != 0) {
  40                         glDeleteTextures(1, &nodes[i]->output_texture);
  41                 }
  42                 delete nodes[i]->effect;
  43                 delete nodes[i];
  44         }
  45         for (unsigned i = 0; i < phases.size(); ++i) {
  46                 glDeleteProgram(phases[i]->glsl_program_num);
  47                 glDeleteShader(phases[i]->vertex_shader);
  48                 glDeleteShader(phases[i]->fragment_shader);
  49                 delete phases[i];
  50         }
  51         if (fbo != 0) {
  52                 glDeleteFramebuffers(1, &fbo);
  53         }
  54 }
  55
  56 Input *EffectChain::add_input(Input *input)
  57 {
  58         assert(!finalized);
  59         inputs.push_back(input);
  60         add_node(input);
  61         return input;
  62 }
  63
  64 void EffectChain::add_output(const ImageFormat &format, OutputAlphaFormat alpha_format)
  65 {
  66         assert(!finalized);
  67         output_format = format;
  68         output_alpha_format = alpha_format;
  69 }
  70
  71 Node *EffectChain::add_node(Effect *effect)
  72 {
  73         char effect_id[256];
  74         sprintf(effect_id, "eff%u", (unsigned)nodes.size());
  75
  76         Node *node = new Node;
  77         node->effect = effect;
  78         node->disabled = false;
  79         node->effect_id = effect_id;
  80         node->output_color_space = COLORSPACE_INVALID;
  81         node->output_gamma_curve = GAMMA_INVALID;
  82         node->output_alpha_type = ALPHA_INVALID;
  83         node->output_texture = 0;
  84
  85         nodes.push_back(node);
  86         node_map[effect] = node;
  87         return node;
  88 }
  89
  90 void EffectChain::connect_nodes(Node *sender, Node *receiver)
  91 {
  92         sender->outgoing_links.push_back(receiver);
  93         receiver->incoming_links.push_back(sender);
  94 }
  95
  96 void EffectChain::replace_receiver(Node *old_receiver, Node *new_receiver)
  97 {
  98         new_receiver->incoming_links = old_receiver->incoming_links;
  99         old_receiver->incoming_links.clear();
 100
 101         for (unsigned i = 0; i < new_receiver->incoming_links.size(); ++i) {
 102                 Node *sender = new_receiver->incoming_links[i];
 103                 for (unsigned j = 0; j < sender->outgoing_links.size(); ++j) {
 104                         if (sender->outgoing_links[j] == old_receiver) {
 105                                 sender->outgoing_links[j] = new_receiver;
 106                         }
 107                 }
 108         }
 109 }
 110
 111 void EffectChain::replace_sender(Node *old_sender, Node *new_sender)
 112 {
 113         new_sender->outgoing_links = old_sender->outgoing_links;
 114         old_sender->outgoing_links.clear();
 115
 116         for (unsigned i = 0; i < new_sender->outgoing_links.size(); ++i) {
 117                 Node *receiver = new_sender->outgoing_links[i];
 118                 for (unsigned j = 0; j < receiver->incoming_links.size(); ++j) {
 119                         if (receiver->incoming_links[j] == old_sender) {
 120                                 receiver->incoming_links[j] = new_sender;
 121                         }
 122                 }
 123         }
 124 }
 125
 126 void EffectChain::insert_node_between(Node *sender, Node *middle, Node *receiver)
 127 {
 128         for (unsigned i = 0; i < sender->outgoing_links.size(); ++i) {
 129                 if (sender->outgoing_links[i] == receiver) {
 130                         sender->outgoing_links[i] = middle;
 131                         middle->incoming_links.push_back(sender);
 132                 }
 133         }
 134         for (unsigned i = 0; i < receiver->incoming_links.size(); ++i) {
 135                 if (receiver->incoming_links[i] == sender) {
 136                         receiver->incoming_links[i] = middle;
 137                         middle->outgoing_links.push_back(receiver);
 138                 }
 139         }
 140
 141         assert(middle->incoming_links.size() == middle->effect->num_inputs());
 142 }
 143
 144 void EffectChain::find_all_nonlinear_inputs(Node *node, std::vector<Node *> *nonlinear_inputs)
 145 {
 146         if (node->output_gamma_curve == GAMMA_LINEAR &&
 147             node->effect->effect_type_id() != "GammaCompressionEffect") {
 148                 return;
 149         }
 150         if (node->effect->num_inputs() == 0) {
 151                 nonlinear_inputs->push_back(node);
 152         } else {
 153                 assert(node->effect->num_inputs() == node->incoming_links.size());
 154                 for (unsigned i = 0; i < node->incoming_links.size(); ++i) {
 155                         find_all_nonlinear_inputs(node->incoming_links[i], nonlinear_inputs);
 156                 }
 157         }
 158 }
 159
 160 Effect *EffectChain::add_effect(Effect *effect, const std::vector<Effect *> &inputs)
 161 {
 162         assert(!finalized);
 163         assert(inputs.size() == effect->num_inputs());
 164         Node *node = add_node(effect);
 165         for (unsigned i = 0; i < inputs.size(); ++i) {
 166                 assert(node_map.count(inputs[i]) != 0);
 167                 connect_nodes(node_map[inputs[i]], node);
 168         }
 169         return effect;
 170 }
 171
 172 // GLSL pre-1.30 doesn't support token pasting. Replace PREFIX(x) with <effect_id>_x.
 173 std::string replace_prefix(const std::string &text, const std::string &prefix)
 174 {
 175         std::string output;
 176         size_t start = 0;
 177
 178         while (start < text.size()) {
 179                 size_t pos = text.find("PREFIX(", start);
 180                 if (pos == std::string::npos) {
 181                         output.append(text.substr(start, std::string::npos));
 182                         break;
 183                 }
 184
 185                 output.append(text.substr(start, pos - start));
 186                 output.append(prefix);
 187                 output.append("_");
 188
 189                 pos += strlen("PREFIX(");
 190
 191                 // Output stuff until we find the matching ), which we then eat.
 192                 int depth = 1;
 193                 size_t end_arg_pos = pos;
 194                 while (end_arg_pos < text.size()) {
 195                         if (text[end_arg_pos] == '(') {
 196                                 ++depth;
 197                         } else if (text[end_arg_pos] == ')') {
 198                                 --depth;
 199                                 if (depth == 0) {
 200                                         break;
 201                                 }
 202                         }
 203                         ++end_arg_pos;
 204                 }
 205                 output.append(text.substr(pos, end_arg_pos - pos));
 206                 ++end_arg_pos;
 207                 assert(depth == 0);
 208                 start = end_arg_pos;
 209         }
 210         return output;
 211 }
 212
 213 Phase *EffectChain::compile_glsl_program(
 214         const std::vector<Node *> &inputs,
 215         const std::vector<Node *> &effects)
 216 {
 217         assert(!effects.empty());
 218
 219         // Deduplicate the inputs.
 220         std::vector<Node *> true_inputs = inputs;
 221         std::sort(true_inputs.begin(), true_inputs.end());
 222         true_inputs.erase(std::unique(true_inputs.begin(), true_inputs.end()), true_inputs.end());
 223
 224         bool input_needs_mipmaps = false;
 225         std::string frag_shader = read_file("header.frag");
 226
 227         // Create functions for all the texture inputs that we need.
 228         for (unsigned i = 0; i < true_inputs.size(); ++i) {
 229                 Node *input = true_inputs[i];
 230
 231                 frag_shader += std::string("uniform sampler2D tex_") + input->effect_id + ";\n";
 232                 frag_shader += std::string("vec4 ") + input->effect_id + "(vec2 tc) {\n";
 233                 frag_shader += "\treturn texture2D(tex_" + input->effect_id + ", tc);\n";
 234                 frag_shader += "}\n";
 235                 frag_shader += "\n";
 236         }
 237
 238         std::vector<Node *> sorted_effects = topological_sort(effects);
 239
 240         for (unsigned i = 0; i < sorted_effects.size(); ++i) {
 241                 Node *node = sorted_effects[i];
 242
 243                 if (node->incoming_links.size() == 1) {
 244                         frag_shader += std::string("#define INPUT ") + node->incoming_links[0]->effect_id + "\n";
 245                 } else {
 246                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 247                                 char buf[256];
 248                                 sprintf(buf, "#define INPUT%d %s\n", j + 1, node->incoming_links[j]->effect_id.c_str());
 249                                 frag_shader += buf;
 250                         }
 251                 }
 252
 253                 frag_shader += "\n";
 254                 frag_shader += std::string("#define FUNCNAME ") + node->effect_id + "\n";
 255                 frag_shader += replace_prefix(node->effect->output_convenience_uniforms(), node->effect_id);
 256                 frag_shader += replace_prefix(node->effect->output_fragment_shader(), node->effect_id);
 257                 frag_shader += "#undef PREFIX\n";
 258                 frag_shader += "#undef FUNCNAME\n";
 259                 if (node->incoming_links.size() == 1) {
 260                         frag_shader += "#undef INPUT\n";
 261                 } else {
 262                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 263                                 char buf[256];
 264                                 sprintf(buf, "#undef INPUT%d\n", j + 1);
 265                                 frag_shader += buf;
 266                         }
 267                 }
 268                 frag_shader += "\n";
 269
 270                 input_needs_mipmaps |= node->effect->needs_mipmaps();
 271         }
 272         for (unsigned i = 0; i < sorted_effects.size(); ++i) {
 273                 Node *node = sorted_effects[i];
 274                 if (node->effect->num_inputs() == 0) {
 275                         CHECK(node->effect->set_int("needs_mipmaps", input_needs_mipmaps));
 276                 }
 277         }
 278         frag_shader += std::string("#define INPUT ") + sorted_effects.back()->effect_id + "\n";
 279         frag_shader.append(read_file("footer.frag"));
 280
 281         if (movit_debug_level == MOVIT_DEBUG_ON) {
 282                 // Output shader to a temporary file, for easier debugging.
 283                 static int compiled_shader_num = 0;
 284                 char filename[256];
 285                 sprintf(filename, "chain-%03d.frag", compiled_shader_num++);
 286                 FILE *fp = fopen(filename, "w");
 287                 if (fp == NULL) {
 288                         perror(filename);
 289                         exit(1);
 290                 }
 291                 fprintf(fp, "%s\n", frag_shader.c_str());
 292                 fclose(fp);
 293         }
 294
 295         GLuint glsl_program_num = glCreateProgram();
 296         GLuint vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 297         GLuint fs_obj = compile_shader(frag_shader, GL_FRAGMENT_SHADER);
 298         glAttachShader(glsl_program_num, vs_obj);
 299         check_error();
 300         glAttachShader(glsl_program_num, fs_obj);
 301         check_error();
 302         glLinkProgram(glsl_program_num);
 303         check_error();
 304
 305         Phase *phase = new Phase;
 306         phase->glsl_program_num = glsl_program_num;
 307         phase->vertex_shader = vs_obj;
 308         phase->fragment_shader = fs_obj;
 309         phase->input_needs_mipmaps = input_needs_mipmaps;
 310         phase->inputs = true_inputs;
 311         phase->effects = sorted_effects;
 312
 313         return phase;
 314 }
 315
 316 // Construct GLSL programs, starting at the given effect and following
 317 // the chain from there. We end a program every time we come to an effect
 318 // marked as "needs texture bounce", one that is used by multiple other
 319 // effects, every time an effect wants to change the output size,
 320 // and of course at the end.
 321 //
 322 // We follow a quite simple depth-first search from the output, although
 323 // without any explicit recursion.
 324 void EffectChain::construct_glsl_programs(Node *output)
 325 {
 326         // Which effects have already been completed?
 327         // We need to keep track of it, as an effect with multiple outputs
 328         // could otherwise be calculated multiple times.
 329         std::set<Node *> completed_effects;
 330
 331         // Effects in the current phase, as well as inputs (outputs from other phases
 332         // that we depend on). Note that since we start iterating from the end,
 333         // the effect list will be in the reverse order.
 334         std::vector<Node *> this_phase_inputs;
 335         std::vector<Node *> this_phase_effects;
 336
 337         // Effects that we have yet to calculate, but that we know should
 338         // be in the current phase.
 339         std::stack<Node *> effects_todo_this_phase;
 340
 341         // Effects that we have yet to calculate, but that come from other phases.
 342         // We delay these until we have this phase done in its entirety,
 343         // at which point we pick any of them and start a new phase from that.
 344         std::stack<Node *> effects_todo_other_phases;
 345
 346         effects_todo_this_phase.push(output);
 347
 348         for ( ;; ) {  // Termination condition within loop.
 349                 if (!effects_todo_this_phase.empty()) {
 350                         // OK, we have more to do this phase.
 351                         Node *node = effects_todo_this_phase.top();
 352                         effects_todo_this_phase.pop();
 353
 354                         // This should currently only happen for effects that are inputs
 355                         // (either true inputs or phase outputs). We special-case inputs,
 356                         // and then deduplicate phase outputs in compile_glsl_program().
 357                         if (node->effect->num_inputs() == 0) {
 358                                 if (find(this_phase_effects.begin(), this_phase_effects.end(), node) != this_phase_effects.end()) {
 359                                         continue;
 360                                 }
 361                         } else {
 362                                 assert(completed_effects.count(node) == 0);
 363                         }
 364
 365                         this_phase_effects.push_back(node);
 366                         completed_effects.insert(node);
 367
 368                         // Find all the dependencies of this effect, and add them to the stack.
 369                         std::vector<Node *> deps = node->incoming_links;
 370                         assert(node->effect->num_inputs() == deps.size());
 371                         for (unsigned i = 0; i < deps.size(); ++i) {
 372                                 bool start_new_phase = false;
 373
 374                                 // FIXME: If we sample directly from a texture, we won't need this.
 375                                 if (node->effect->needs_texture_bounce()) {
 376                                         start_new_phase = true;
 377                                 }
 378
 379                                 if (deps[i]->outgoing_links.size() > 1) {
 380                                         if (deps[i]->effect->num_inputs() > 0) {
 381                                                 // More than one effect uses this as the input,
 382                                                 // and it is not a texture itself.
 383                                                 // The easiest thing to do (and probably also the safest
 384                                                 // performance-wise in most cases) is to bounce it to a texture
 385                                                 // and then let the next passes read from that.
 386                                                 start_new_phase = true;
 387                                         } else {
 388                                                 // For textures, we try to be slightly more clever;
 389                                                 // if none of our outputs need a bounce, we don't bounce
 390                                                 // but instead simply use the effect many times.
 391                                                 //
 392                                                 // Strictly speaking, we could bounce it for some outputs
 393                                                 // and use it directly for others, but the processing becomes
 394                                                 // somewhat simpler if the effect is only used in one such way.
 395                                                 for (unsigned j = 0; j < deps[i]->outgoing_links.size(); ++j) {
 396                                                         Node *rdep = deps[i]->outgoing_links[j];
 397                                                         start_new_phase |= rdep->effect->needs_texture_bounce();
 398                                                 }
 399                                         }
 400                                 }
 401
 402                                 if (deps[i]->effect->changes_output_size()) {
 403                                         start_new_phase = true;
 404                                 }
 405
 406                                 if (start_new_phase) {
 407                                         effects_todo_other_phases.push(deps[i]);
 408                                         this_phase_inputs.push_back(deps[i]);
 409                                 } else {
 410                                         effects_todo_this_phase.push(deps[i]);
 411                                 }
 412                         }
 413                         continue;
 414                 }
 415
 416                 // No more effects to do this phase. Take all the ones we have,
 417                 // and create a GLSL program for it.
 418                 if (!this_phase_effects.empty()) {
 419                         reverse(this_phase_effects.begin(), this_phase_effects.end());
 420                         phases.push_back(compile_glsl_program(this_phase_inputs, this_phase_effects));
 421                         this_phase_effects.back()->phase = phases.back();
 422                         this_phase_inputs.clear();
 423                         this_phase_effects.clear();
 424                 }
 425                 assert(this_phase_inputs.empty());
 426                 assert(this_phase_effects.empty());
 427
 428                 // If we have no effects left, exit.
 429                 if (effects_todo_other_phases.empty()) {
 430                         break;
 431                 }
 432
 433                 Node *node = effects_todo_other_phases.top();
 434                 effects_todo_other_phases.pop();
 435
 436                 if (completed_effects.count(node) == 0) {
 437                         // Start a new phase, calculating from this effect.
 438                         effects_todo_this_phase.push(node);
 439                 }
 440         }
 441
 442         // Finally, since the phases are found from the output but must be executed
 443         // from the input(s), reverse them, too.
 444         std::reverse(phases.begin(), phases.end());
 445 }
 446
 447 void EffectChain::output_dot(const char *filename)
 448 {
 449         if (movit_debug_level != MOVIT_DEBUG_ON) {
 450                 return;
 451         }
 452
 453         FILE *fp = fopen(filename, "w");
 454         if (fp == NULL) {
 455                 perror(filename);
 456                 exit(1);
 457         }
 458
 459         fprintf(fp, "digraph G {\n");
 460         fprintf(fp, "  output [shape=box label=\"(output)\"];\n");
 461         for (unsigned i = 0; i < nodes.size(); ++i) {
 462                 // Find out which phase this event belongs to.
 463                 std::vector<int> in_phases;
 464                 for (unsigned j = 0; j < phases.size(); ++j) {
 465                         const Phase* p = phases[j];
 466                         if (std::find(p->effects.begin(), p->effects.end(), nodes[i]) != p->effects.end()) {
 467                                 in_phases.push_back(j);
 468                         }
 469                 }
 470
 471                 if (in_phases.empty()) {
 472                         fprintf(fp, "  n%ld [label=\"%s\"];\n", (long)nodes[i], nodes[i]->effect->effect_type_id().c_str());
 473                 } else if (in_phases.size() == 1) {
 474                         fprintf(fp, "  n%ld [label=\"%s\" style=\"filled\" fillcolor=\"/accent8/%d\"];\n",
 475                                 (long)nodes[i], nodes[i]->effect->effect_type_id().c_str(),
 476                                 (in_phases[0] % 8) + 1);
 477                 } else {
 478                         // If we had new enough Graphviz, style="wedged" would probably be ideal here.
 479                         // But alas.
 480                         fprintf(fp, "  n%ld [label=\"%s [in multiple phases]\" style=\"filled\" fillcolor=\"/accent8/%d\"];\n",
 481                                 (long)nodes[i], nodes[i]->effect->effect_type_id().c_str(),
 482                                 (in_phases[0] % 8) + 1);
 483                 }
 484
 485                 char from_node_id[256];
 486                 snprintf(from_node_id, 256, "n%ld", (long)nodes[i]);
 487
 488                 for (unsigned j = 0; j < nodes[i]->outgoing_links.size(); ++j) {
 489                         char to_node_id[256];
 490                         snprintf(to_node_id, 256, "n%ld", (long)nodes[i]->outgoing_links[j]);
 491
 492                         std::vector<std::string> labels = get_labels_for_edge(nodes[i], nodes[i]->outgoing_links[j]);
 493                         output_dot_edge(fp, from_node_id, to_node_id, labels);
 494                 }
 495
 496                 if (nodes[i]->outgoing_links.empty() && !nodes[i]->disabled) {
 497                         // Output node.
 498                         std::vector<std::string> labels = get_labels_for_edge(nodes[i], NULL);
 499                         output_dot_edge(fp, from_node_id, "output", labels);
 500                 }
 501         }
 502         fprintf(fp, "}\n");
 503
 504         fclose(fp);
 505 }
 506
 507 std::vector<std::string> EffectChain::get_labels_for_edge(const Node *from, const Node *to)
 508 {
 509         std::vector<std::string> labels;
 510
 511         if (to != NULL && to->effect->needs_texture_bounce()) {
 512                 labels.push_back("needs_bounce");
 513         }
 514         if (from->effect->changes_output_size()) {
 515                 labels.push_back("resize");
 516         }
 517
 518         switch (from->output_color_space) {
 519         case COLORSPACE_INVALID:
 520                 labels.push_back("spc[invalid]");
 521                 break;
 522         case COLORSPACE_REC_601_525:
 523                 labels.push_back("spc[rec601-525]");
 524                 break;
 525         case COLORSPACE_REC_601_625:
 526                 labels.push_back("spc[rec601-625]");
 527                 break;
 528         default:
 529                 break;
 530         }
 531
 532         switch (from->output_gamma_curve) {
 533         case GAMMA_INVALID:
 534                 labels.push_back("gamma[invalid]");
 535                 break;
 536         case GAMMA_sRGB:
 537                 labels.push_back("gamma[sRGB]");
 538                 break;
 539         case GAMMA_REC_601:  // and GAMMA_REC_709
 540                 labels.push_back("gamma[rec601/709]");
 541                 break;
 542         default:
 543                 break;
 544         }
 545
 546         switch (from->output_alpha_type) {
 547         case ALPHA_INVALID:
 548                 labels.push_back("alpha[invalid]");
 549                 break;
 550         case ALPHA_BLANK:
 551                 labels.push_back("alpha[blank]");
 552                 break;
 553         case ALPHA_POSTMULTIPLIED:
 554                 labels.push_back("alpha[postmult]");
 555                 break;
 556         default:
 557                 break;
 558         }
 559
 560         return labels;
 561 }
 562
 563 void EffectChain::output_dot_edge(FILE *fp,
 564                                   const std::string &from_node_id,
 565                                   const std::string &to_node_id,
 566                                   const std::vector<std::string> &labels)
 567 {
 568         if (labels.empty()) {
 569                 fprintf(fp, "  %s -> %s;\n", from_node_id.c_str(), to_node_id.c_str());
 570         } else {
 571                 std::string label = labels[0];
 572                 for (unsigned k = 1; k < labels.size(); ++k) {
 573                         label += ", " + labels[k];
 574                 }
 575                 fprintf(fp, "  %s -> %s [label=\"%s\"];\n", from_node_id.c_str(), to_node_id.c_str(), label.c_str());
 576         }
 577 }
 578
 579 void EffectChain::size_rectangle_to_fit(unsigned width, unsigned height, unsigned *output_width, unsigned *output_height)
 580 {
 581         unsigned scaled_width, scaled_height;
 582
 583         if (float(width) * aspect_denom >= float(height) * aspect_nom) {
 584                 // Same aspect, or W/H > aspect (image is wider than the frame).
 585                 // In either case, keep width, and adjust height.
 586                 scaled_width = width;
 587                 scaled_height = lrintf(width * aspect_denom / aspect_nom);
 588         } else {
 589                 // W/H < aspect (image is taller than the frame), so keep height,
 590                 // and adjust width.
 591                 scaled_width = lrintf(height * aspect_nom / aspect_denom);
 592                 scaled_height = height;
 593         }
 594
 595         // We should be consistently larger or smaller then the existing choice,
 596         // since we have the same aspect.
 597         assert(!(scaled_width < *output_width && scaled_height > *output_height));
 598         assert(!(scaled_height < *output_height && scaled_width > *output_width));
 599
 600         if (scaled_width >= *output_width && scaled_height >= *output_height) {
 601                 *output_width = scaled_width;
 602                 *output_height = scaled_height;
 603         }
 604 }
 605
 606 // Propagate input texture sizes throughout, and inform effects downstream.
 607 // (Like a lot of other code, we depend on effects being in topological order.)
 608 void EffectChain::inform_input_sizes(Phase *phase)
 609 {
 610         // All effects that have a defined size (inputs and RTT inputs)
 611         // get that. Reset all others.
 612         for (unsigned i = 0; i < phase->effects.size(); ++i) {
 613                 Node *node = phase->effects[i];
 614                 if (node->effect->num_inputs() == 0) {
 615                         Input *input = static_cast<Input *>(node->effect);
 616                         node->output_width = input->get_width();
 617                         node->output_height = input->get_height();
 618                         assert(node->output_width != 0);
 619                         assert(node->output_height != 0);
 620                 } else {
 621                         node->output_width = node->output_height = 0;
 622                 }
 623         }
 624         for (unsigned i = 0; i < phase->inputs.size(); ++i) {
 625                 Node *input = phase->inputs[i];
 626                 input->output_width = input->phase->virtual_output_width;
 627                 input->output_height = input->phase->virtual_output_height;
 628                 assert(input->output_width != 0);
 629                 assert(input->output_height != 0);
 630         }
 631
 632         // Now propagate from the inputs towards the end, and inform as we go.
 633         // The rules are simple:
 634         //
 635         //   1. Don't touch effects that already have given sizes (ie., inputs).
 636         //   2. If all of your inputs have the same size, that will be your output size.
 637         //   3. Otherwise, your output size is 0x0.
 638         for (unsigned i = 0; i < phase->effects.size(); ++i) {
 639                 Node *node = phase->effects[i];
 640                 if (node->effect->num_inputs() == 0) {
 641                         continue;
 642                 }
 643                 unsigned this_output_width = 0;
 644                 unsigned this_output_height = 0;
 645                 for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 646                         Node *input = node->incoming_links[j];
 647                         node->effect->inform_input_size(j, input->output_width, input->output_height);
 648                         if (j == 0) {
 649                                 this_output_width = input->output_width;
 650                                 this_output_height = input->output_height;
 651                         } else if (input->output_width != this_output_width || input->output_height != this_output_height) {
 652                                 // Inputs disagree.
 653                                 this_output_width = 0;
 654                                 this_output_height = 0;
 655                         }
 656                 }
 657                 node->output_width = this_output_width;
 658                 node->output_height = this_output_height;
 659         }
 660 }
 661
 662 // Note: You should call inform_input_sizes() before this, as the last effect's
 663 // desired output size might change based on the inputs.
 664 void EffectChain::find_output_size(Phase *phase)
 665 {
 666         Node *output_node = phase->effects.back();
 667
 668         // If the last effect explicitly sets an output size, use that.
 669         if (output_node->effect->changes_output_size()) {
 670                 output_node->effect->get_output_size(&phase->output_width, &phase->output_height,
 671                                                      &phase->virtual_output_width, &phase->virtual_output_height);
 672                 return;
 673         }
 674
 675         // If all effects have the same size, use that.
 676         unsigned output_width = 0, output_height = 0;
 677         bool all_inputs_same_size = true;
 678
 679         for (unsigned i = 0; i < phase->inputs.size(); ++i) {
 680                 Node *input = phase->inputs[i];
 681                 assert(input->phase->output_width != 0);
 682                 assert(input->phase->output_height != 0);
 683                 if (output_width == 0 && output_height == 0) {
 684                         output_width = input->phase->virtual_output_width;
 685                         output_height = input->phase->virtual_output_height;
 686                 } else if (output_width != input->phase->virtual_output_width ||
 687                            output_height != input->phase->virtual_output_height) {
 688                         all_inputs_same_size = false;
 689                 }
 690         }
 691         for (unsigned i = 0; i < phase->effects.size(); ++i) {
 692                 Effect *effect = phase->effects[i]->effect;
 693                 if (effect->num_inputs() != 0) {
 694                         continue;
 695                 }
 696
 697                 Input *input = static_cast<Input *>(effect);
 698                 if (output_width == 0 && output_height == 0) {
 699                         output_width = input->get_width();
 700                         output_height = input->get_height();
 701                 } else if (output_width != input->get_width() ||
 702                            output_height != input->get_height()) {
 703                         all_inputs_same_size = false;
 704                 }
 705         }
 706
 707         if (all_inputs_same_size) {
 708                 assert(output_width != 0);
 709                 assert(output_height != 0);
 710                 phase->virtual_output_width = phase->output_width = output_width;
 711                 phase->virtual_output_height = phase->output_height = output_height;
 712                 return;
 713         }
 714
 715         // If not, fit all the inputs into the current aspect, and select the largest one.
 716         output_width = 0;
 717         output_height = 0;
 718         for (unsigned i = 0; i < phase->inputs.size(); ++i) {
 719                 Node *input = phase->inputs[i];
 720                 assert(input->phase->output_width != 0);
 721                 assert(input->phase->output_height != 0);
 722                 size_rectangle_to_fit(input->phase->output_width, input->phase->output_height, &output_width, &output_height);
 723         }
 724         for (unsigned i = 0; i < phase->effects.size(); ++i) {
 725                 Effect *effect = phase->effects[i]->effect;
 726                 if (effect->num_inputs() != 0) {
 727                         continue;
 728                 }
 729
 730                 Input *input = static_cast<Input *>(effect);
 731                 size_rectangle_to_fit(input->get_width(), input->get_height(), &output_width, &output_height);
 732         }
 733         assert(output_width != 0);
 734         assert(output_height != 0);
 735         phase->virtual_output_width = phase->output_width = output_width;
 736         phase->virtual_output_height = phase->output_height = output_height;
 737 }
 738
 739 void EffectChain::sort_all_nodes_topologically()
 740 {
 741         nodes = topological_sort(nodes);
 742 }
 743
 744 std::vector<Node *> EffectChain::topological_sort(const std::vector<Node *> &nodes)
 745 {
 746         std::set<Node *> nodes_left_to_visit(nodes.begin(), nodes.end());
 747         std::vector<Node *> sorted_list;
 748         for (unsigned i = 0; i < nodes.size(); ++i) {
 749                 topological_sort_visit_node(nodes[i], &nodes_left_to_visit, &sorted_list);
 750         }
 751         reverse(sorted_list.begin(), sorted_list.end());
 752         return sorted_list;
 753 }
 754
 755 void EffectChain::topological_sort_visit_node(Node *node, std::set<Node *> *nodes_left_to_visit, std::vector<Node *> *sorted_list)
 756 {
 757         if (nodes_left_to_visit->count(node) == 0) {
 758                 return;
 759         }
 760         nodes_left_to_visit->erase(node);
 761         for (unsigned i = 0; i < node->outgoing_links.size(); ++i) {
 762                 topological_sort_visit_node(node->outgoing_links[i], nodes_left_to_visit, sorted_list);
 763         }
 764         sorted_list->push_back(node);
 765 }
 766
 767 void EffectChain::find_color_spaces_for_inputs()
 768 {
 769         for (unsigned i = 0; i < nodes.size(); ++i) {
 770                 Node *node = nodes[i];
 771                 if (node->disabled) {
 772                         continue;
 773                 }
 774                 if (node->incoming_links.size() == 0) {
 775                         Input *input = static_cast<Input *>(node->effect);
 776                         node->output_color_space = input->get_color_space();
 777                         node->output_gamma_curve = input->get_gamma_curve();
 778
 779                         Effect::AlphaHandling alpha_handling = input->alpha_handling();
 780                         switch (alpha_handling) {
 781                         case Effect::OUTPUT_BLANK_ALPHA:
 782                                 node->output_alpha_type = ALPHA_BLANK;
 783                                 break;
 784                         case Effect::INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA:
 785                                 node->output_alpha_type = ALPHA_PREMULTIPLIED;
 786                                 break;
 787                         case Effect::OUTPUT_POSTMULTIPLIED_ALPHA:
 788                                 node->output_alpha_type = ALPHA_POSTMULTIPLIED;
 789                                 break;
 790                         case Effect::INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK:
 791                         case Effect::DONT_CARE_ALPHA_TYPE:
 792                         default:
 793                                 assert(false);
 794                         }
 795
 796                         if (node->output_alpha_type == ALPHA_PREMULTIPLIED) {
 797                                 assert(node->output_gamma_curve == GAMMA_LINEAR);
 798                         }
 799                 }
 800         }
 801 }
 802
 803 // Propagate gamma and color space information as far as we can in the graph.
 804 // The rules are simple: Anything where all the inputs agree, get that as
 805 // output as well. Anything else keeps having *_INVALID.
 806 void EffectChain::propagate_gamma_and_color_space()
 807 {
 808         // We depend on going through the nodes in order.
 809         sort_all_nodes_topologically();
 810
 811         for (unsigned i = 0; i < nodes.size(); ++i) {
 812                 Node *node = nodes[i];
 813                 if (node->disabled) {
 814                         continue;
 815                 }
 816                 assert(node->incoming_links.size() == node->effect->num_inputs());
 817                 if (node->incoming_links.size() == 0) {
 818                         assert(node->output_color_space != COLORSPACE_INVALID);
 819                         assert(node->output_gamma_curve != GAMMA_INVALID);
 820                         continue;
 821                 }
 822
 823                 Colorspace color_space = node->incoming_links[0]->output_color_space;
 824                 GammaCurve gamma_curve = node->incoming_links[0]->output_gamma_curve;
 825                 for (unsigned j = 1; j < node->incoming_links.size(); ++j) {
 826                         if (node->incoming_links[j]->output_color_space != color_space) {
 827                                 color_space = COLORSPACE_INVALID;
 828                         }
 829                         if (node->incoming_links[j]->output_gamma_curve != gamma_curve) {
 830                                 gamma_curve = GAMMA_INVALID;
 831                         }
 832                 }
 833
 834                 // The conversion effects already have their outputs set correctly,
 835                 // so leave them alone.
 836                 if (node->effect->effect_type_id() != "ColorspaceConversionEffect") {
 837                         node->output_color_space = color_space;
 838                 }
 839                 if (node->effect->effect_type_id() != "GammaCompressionEffect" &&
 840                     node->effect->effect_type_id() != "GammaExpansionEffect") {
 841                         node->output_gamma_curve = gamma_curve;
 842                 }
 843         }
 844 }
 845
 846 // Propagate alpha information as far as we can in the graph.
 847 // Similar to propagate_gamma_and_color_space().
 848 void EffectChain::propagate_alpha()
 849 {
 850         // We depend on going through the nodes in order.
 851         sort_all_nodes_topologically();
 852
 853         for (unsigned i = 0; i < nodes.size(); ++i) {
 854                 Node *node = nodes[i];
 855                 if (node->disabled) {
 856                         continue;
 857                 }
 858                 assert(node->incoming_links.size() == node->effect->num_inputs());
 859                 if (node->incoming_links.size() == 0) {
 860                         assert(node->output_alpha_type != ALPHA_INVALID);
 861                         continue;
 862                 }
 863
 864                 // The alpha multiplication/division effects are special cases.
 865                 if (node->effect->effect_type_id() == "AlphaMultiplicationEffect") {
 866                         assert(node->incoming_links.size() == 1);
 867                         assert(node->incoming_links[0]->output_alpha_type == ALPHA_POSTMULTIPLIED);
 868                         node->output_alpha_type = ALPHA_PREMULTIPLIED;
 869                         continue;
 870                 }
 871                 if (node->effect->effect_type_id() == "AlphaDivisionEffect") {
 872                         assert(node->incoming_links.size() == 1);
 873                         assert(node->incoming_links[0]->output_alpha_type == ALPHA_PREMULTIPLIED);
 874                         node->output_alpha_type = ALPHA_POSTMULTIPLIED;
 875                         continue;
 876                 }
 877
 878                 // GammaCompressionEffect and GammaExpansionEffect are also a special case,
 879                 // because they are the only one that _need_ postmultiplied alpha.
 880                 if (node->effect->effect_type_id() == "GammaCompressionEffect" ||
 881                     node->effect->effect_type_id() == "GammaExpansionEffect") {
 882                         assert(node->incoming_links.size() == 1);
 883                         if (node->incoming_links[0]->output_alpha_type == ALPHA_BLANK) {
 884                                 node->output_alpha_type = ALPHA_BLANK;
 885                         } else if (node->incoming_links[0]->output_alpha_type == ALPHA_POSTMULTIPLIED) {
 886                                 node->output_alpha_type = ALPHA_POSTMULTIPLIED;
 887                         } else {
 888                                 node->output_alpha_type = ALPHA_INVALID;
 889                         }
 890                         continue;
 891                 }
 892
 893                 // Only inputs can have unconditional alpha output (OUTPUT_BLANK_ALPHA
 894                 // or OUTPUT_POSTMULTIPLIED_ALPHA), and they have already been
 895                 // taken care of above. Rationale: Even if you could imagine
 896                 // e.g. an effect that took in an image and set alpha=1.0
 897                 // unconditionally, it wouldn't make any sense to have it as
 898                 // e.g. OUTPUT_BLANK_ALPHA, since it wouldn't know whether it
 899                 // got its input pre- or postmultiplied, so it wouldn't know
 900                 // whether to divide away the old alpha or not.
 901                 Effect::AlphaHandling alpha_handling = node->effect->alpha_handling();
 902                 assert(alpha_handling == Effect::INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA ||
 903                        alpha_handling == Effect::INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK ||
 904                        alpha_handling == Effect::DONT_CARE_ALPHA_TYPE);
 905
 906                 // If the node has multiple inputs, check that they are all valid and
 907                 // the same.
 908                 bool any_invalid = false;
 909                 bool any_premultiplied = false;
 910                 bool any_postmultiplied = false;
 911
 912                 for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 913                         switch (node->incoming_links[j]->output_alpha_type) {
 914                         case ALPHA_INVALID:
 915                                 any_invalid = true;
 916                                 break;
 917                         case ALPHA_BLANK:
 918                                 // Blank is good as both pre- and postmultiplied alpha,
 919                                 // so just ignore it.
 920                                 break;
 921                         case ALPHA_PREMULTIPLIED:
 922                                 any_premultiplied = true;
 923                                 break;
 924                         case ALPHA_POSTMULTIPLIED:
 925                                 any_postmultiplied = true;
 926                                 break;
 927                         default:
 928                                 assert(false);
 929                         }
 930                 }
 931
 932                 if (any_invalid) {
 933                         node->output_alpha_type = ALPHA_INVALID;
 934                         continue;
 935                 }
 936
 937                 // Inputs must be of the same type.
 938                 if (any_premultiplied && any_postmultiplied) {
 939                         node->output_alpha_type = ALPHA_INVALID;
 940                         continue;
 941                 }
 942
 943                 if (alpha_handling == Effect::INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA ||
 944                     alpha_handling == Effect::INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK) {
 945                         // If the effect has asked for premultiplied alpha, check that it has got it.
 946                         if (any_postmultiplied) {
 947                                 node->output_alpha_type = ALPHA_INVALID;
 948                         } else if (!any_premultiplied &&
 949                                    alpha_handling == Effect::INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK) {
 950                                 // Blank input alpha, and the effect preserves blank alpha.
 951                                 node->output_alpha_type = ALPHA_BLANK;
 952                         } else {
 953                                 node->output_alpha_type = ALPHA_PREMULTIPLIED;
 954                         }
 955                 } else {
 956                         // OK, all inputs are the same, and this effect is not going
 957                         // to change it.
 958                         assert(alpha_handling == Effect::DONT_CARE_ALPHA_TYPE);
 959                         if (any_premultiplied) {
 960                                 node->output_alpha_type = ALPHA_PREMULTIPLIED;
 961                         } else if (any_postmultiplied) {
 962                                 node->output_alpha_type = ALPHA_POSTMULTIPLIED;
 963                         } else {
 964                                 node->output_alpha_type = ALPHA_BLANK;
 965                         }
 966                 }
 967         }
 968 }
 969
 970 bool EffectChain::node_needs_colorspace_fix(Node *node)
 971 {
 972         if (node->disabled) {
 973                 return false;
 974         }
 975         if (node->effect->num_inputs() == 0) {
 976                 return false;
 977         }
 978
 979         // propagate_gamma_and_color_space() has already set our output
 980         // to COLORSPACE_INVALID if the inputs differ, so we can rely on that.
 981         if (node->output_color_space == COLORSPACE_INVALID) {
 982                 return true;
 983         }
 984         return (node->effect->needs_srgb_primaries() && node->output_color_space != COLORSPACE_sRGB);
 985 }
 986
 987 // Fix up color spaces so that there are no COLORSPACE_INVALID nodes left in
 988 // the graph. Our strategy is not always optimal, but quite simple:
 989 // Find an effect that's as early as possible where the inputs are of
 990 // unacceptable colorspaces (that is, either different, or, if the effect only
 991 // wants sRGB, not sRGB.) Add appropriate conversions on all its inputs,
 992 // propagate the information anew, and repeat until there are no more such
 993 // effects.
 994 void EffectChain::fix_internal_color_spaces()
 995 {
 996         unsigned colorspace_propagation_pass = 0;
 997         bool found_any;
 998         do {
 999                 found_any = false;
1000                 for (unsigned i = 0; i < nodes.size(); ++i) {
1001                         Node *node = nodes[i];
1002                         if (!node_needs_colorspace_fix(node)) {
1003                                 continue;
1004                         }
1005
1006                         // Go through each input that is not sRGB, and insert
1007                         // a colorspace conversion after it.
1008                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
1009                                 Node *input = node->incoming_links[j];
1010                                 assert(input->output_color_space != COLORSPACE_INVALID);
1011                                 if (input->output_color_space == COLORSPACE_sRGB) {
1012                                         continue;
1013                                 }
1014                                 Node *conversion = add_node(new ColorspaceConversionEffect());
1015                                 CHECK(conversion->effect->set_int("source_space", input->output_color_space));
1016                                 CHECK(conversion->effect->set_int("destination_space", COLORSPACE_sRGB));
1017                                 conversion->output_color_space = COLORSPACE_sRGB;
1018                                 replace_sender(input, conversion);
1019                                 connect_nodes(input, conversion);
1020                         }
1021
1022                         // Re-sort topologically, and propagate the new information.
1023                         propagate_gamma_and_color_space();
1024
1025                         found_any = true;
1026                         break;
1027                 }
1028
1029                 char filename[256];
1030                 sprintf(filename, "step5-colorspacefix-iter%u.dot", ++colorspace_propagation_pass);
1031                 output_dot(filename);
1032                 assert(colorspace_propagation_pass < 100);
1033         } while (found_any);
1034
1035         for (unsigned i = 0; i < nodes.size(); ++i) {
1036                 Node *node = nodes[i];
1037                 if (node->disabled) {
1038                         continue;
1039                 }
1040                 assert(node->output_color_space != COLORSPACE_INVALID);
1041         }
1042 }
1043
1044 bool EffectChain::node_needs_alpha_fix(Node *node)
1045 {
1046         if (node->disabled) {
1047                 return false;
1048         }
1049
1050         // propagate_alpha() has already set our output to ALPHA_INVALID if the
1051         // inputs differ or we are otherwise in mismatch, so we can rely on that.
1052         return (node->output_alpha_type == ALPHA_INVALID);
1053 }
1054
1055 // Fix up alpha so that there are no ALPHA_INVALID nodes left in
1056 // the graph. Similar to fix_internal_color_spaces().
1057 void EffectChain::fix_internal_alpha(unsigned step)
1058 {
1059         unsigned alpha_propagation_pass = 0;
1060         bool found_any;
1061         do {
1062                 found_any = false;
1063                 for (unsigned i = 0; i < nodes.size(); ++i) {
1064                         Node *node = nodes[i];
1065                         if (!node_needs_alpha_fix(node)) {
1066                                 continue;
1067                         }
1068
1069                         // If we need to fix up GammaExpansionEffect, then clearly something
1070                         // is wrong, since the combination of premultiplied alpha and nonlinear inputs
1071                         // is meaningless.
1072                         assert(node->effect->effect_type_id() != "GammaExpansionEffect");
1073
1074                         AlphaType desired_type = ALPHA_PREMULTIPLIED;
1075
1076                         // GammaCompressionEffect is special; it needs postmultiplied alpha.
1077                         if (node->effect->effect_type_id() == "GammaCompressionEffect") {
1078                                 assert(node->incoming_links.size() == 1);
1079                                 assert(node->incoming_links[0]->output_alpha_type == ALPHA_PREMULTIPLIED);
1080                                 desired_type = ALPHA_POSTMULTIPLIED;
1081                         }
1082
1083                         // Go through each input that is not premultiplied alpha, and insert
1084                         // a conversion before it.
1085                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
1086                                 Node *input = node->incoming_links[j];
1087                                 assert(input->output_alpha_type != ALPHA_INVALID);
1088                                 if (input->output_alpha_type == desired_type ||
1089                                     input->output_alpha_type == ALPHA_BLANK) {
1090                                         continue;
1091                                 }
1092                                 Node *conversion;
1093                                 if (desired_type == ALPHA_PREMULTIPLIED) {
1094                                         conversion = add_node(new AlphaMultiplicationEffect());
1095                                 } else {
1096                                         conversion = add_node(new AlphaDivisionEffect());
1097                                 }
1098                                 conversion->output_alpha_type = desired_type;
1099                                 replace_sender(input, conversion);
1100                                 connect_nodes(input, conversion);
1101                         }
1102
1103                         // Re-sort topologically, and propagate the new information.
1104                         propagate_gamma_and_color_space();
1105                         propagate_alpha();
1106
1107                         found_any = true;
1108                         break;
1109                 }
1110
1111                 char filename[256];
1112                 sprintf(filename, "step%u-alphafix-iter%u.dot", step, ++alpha_propagation_pass);
1113                 output_dot(filename);
1114                 assert(alpha_propagation_pass < 100);
1115         } while (found_any);
1116
1117         for (unsigned i = 0; i < nodes.size(); ++i) {
1118                 Node *node = nodes[i];
1119                 if (node->disabled) {
1120                         continue;
1121                 }
1122                 assert(node->output_alpha_type != ALPHA_INVALID);
1123         }
1124 }
1125
1126 // Make so that the output is in the desired color space.
1127 void EffectChain::fix_output_color_space()
1128 {
1129         Node *output = find_output_node();
1130         if (output->output_color_space != output_format.color_space) {
1131                 Node *conversion = add_node(new ColorspaceConversionEffect());
1132                 CHECK(conversion->effect->set_int("source_space", output->output_color_space));
1133                 CHECK(conversion->effect->set_int("destination_space", output_format.color_space));
1134                 conversion->output_color_space = output_format.color_space;
1135                 connect_nodes(output, conversion);
1136                 propagate_alpha();
1137                 propagate_gamma_and_color_space();
1138         }
1139 }
1140
1141 // Make so that the output is in the desired pre-/postmultiplication alpha state.
1142 void EffectChain::fix_output_alpha()
1143 {
1144         Node *output = find_output_node();
1145         assert(output->output_alpha_type != ALPHA_INVALID);
1146         if (output->output_alpha_type == ALPHA_BLANK) {
1147                 // No alpha output, so we don't care.
1148                 return;
1149         }
1150         if (output->output_alpha_type == ALPHA_PREMULTIPLIED &&
1151             output_alpha_format == OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED) {
1152                 Node *conversion = add_node(new AlphaDivisionEffect());
1153                 connect_nodes(output, conversion);
1154                 propagate_alpha();
1155                 propagate_gamma_and_color_space();
1156         }
1157         if (output->output_alpha_type == ALPHA_POSTMULTIPLIED &&
1158             output_alpha_format == OUTPUT_ALPHA_FORMAT_PREMULTIPLIED) {
1159                 Node *conversion = add_node(new AlphaMultiplicationEffect());
1160                 connect_nodes(output, conversion);
1161                 propagate_alpha();
1162                 propagate_gamma_and_color_space();
1163         }
1164 }
1165
1166 bool EffectChain::node_needs_gamma_fix(Node *node)
1167 {
1168         if (node->disabled) {
1169                 return false;
1170         }
1171
1172         // Small hack since the output is not an explicit node:
1173         // If we are the last node and our output is in the wrong
1174         // space compared to EffectChain's output, we need to fix it.
1175         // This will only take us to linear, but fix_output_gamma()
1176         // will come and take us to the desired output gamma
1177         // if it is needed.
1178         //
1179         // This needs to be before everything else, since it could
1180         // even apply to inputs (if they are the only effect).
1181         if (node->outgoing_links.empty() &&
1182             node->output_gamma_curve != output_format.gamma_curve &&
1183             node->output_gamma_curve != GAMMA_LINEAR) {
1184                 return true;
1185         }
1186
1187         if (node->effect->num_inputs() == 0) {
1188                 return false;
1189         }
1190
1191         // propagate_gamma_and_color_space() has already set our output
1192         // to GAMMA_INVALID if the inputs differ, so we can rely on that,
1193         // except for GammaCompressionEffect.
1194         if (node->output_gamma_curve == GAMMA_INVALID) {
1195                 return true;
1196         }
1197         if (node->effect->effect_type_id() == "GammaCompressionEffect") {
1198                 assert(node->incoming_links.size() == 1);
1199                 return node->incoming_links[0]->output_gamma_curve != GAMMA_LINEAR;
1200         }
1201
1202         return (node->effect->needs_linear_light() && node->output_gamma_curve != GAMMA_LINEAR);
1203 }
1204
1205 // Very similar to fix_internal_color_spaces(), but for gamma.
1206 // There is one difference, though; before we start adding conversion nodes,
1207 // we see if we can get anything out of asking the sources to deliver
1208 // linear gamma directly. fix_internal_gamma_by_asking_inputs()
1209 // does that part, while fix_internal_gamma_by_inserting_nodes()
1210 // inserts nodes as needed afterwards.
1211 void EffectChain::fix_internal_gamma_by_asking_inputs(unsigned step)
1212 {
1213         unsigned gamma_propagation_pass = 0;
1214         bool found_any;
1215         do {
1216                 found_any = false;
1217                 for (unsigned i = 0; i < nodes.size(); ++i) {
1218                         Node *node = nodes[i];
1219                         if (!node_needs_gamma_fix(node)) {
1220                                 continue;
1221                         }
1222
1223                         // See if all inputs can give us linear gamma. If not, leave it.
1224                         std::vector<Node *> nonlinear_inputs;
1225                         find_all_nonlinear_inputs(node, &nonlinear_inputs);
1226                         assert(!nonlinear_inputs.empty());
1227
1228                         bool all_ok = true;
1229                         for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
1230                                 Input *input = static_cast<Input *>(nonlinear_inputs[i]->effect);
1231                                 all_ok &= input->can_output_linear_gamma();
1232                         }
1233
1234                         if (!all_ok) {
1235                                 continue;
1236                         }
1237
1238                         for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
1239                                 CHECK(nonlinear_inputs[i]->effect->set_int("output_linear_gamma", 1));
1240                                 nonlinear_inputs[i]->output_gamma_curve = GAMMA_LINEAR;
1241                         }
1242
1243                         // Re-sort topologically, and propagate the new information.
1244                         propagate_gamma_and_color_space();
1245
1246                         found_any = true;
1247                         break;
1248                 }
1249
1250                 char filename[256];
1251                 sprintf(filename, "step%u-gammafix-iter%u.dot", step, ++gamma_propagation_pass);
1252                 output_dot(filename);
1253                 assert(gamma_propagation_pass < 100);
1254         } while (found_any);
1255 }
1256
1257 void EffectChain::fix_internal_gamma_by_inserting_nodes(unsigned step)
1258 {
1259         unsigned gamma_propagation_pass = 0;
1260         bool found_any;
1261         do {
1262                 found_any = false;
1263                 for (unsigned i = 0; i < nodes.size(); ++i) {
1264                         Node *node = nodes[i];
1265                         if (!node_needs_gamma_fix(node)) {
1266                                 continue;
1267                         }
1268
1269                         // Special case: We could be an input and still be asked to
1270                         // fix our gamma; if so, we should be the only node
1271                         // (as node_needs_gamma_fix() would only return true in
1272                         // for an input in that case). That means we should insert
1273                         // a conversion node _after_ ourselves.
1274                         if (node->incoming_links.empty()) {
1275                                 assert(node->outgoing_links.empty());
1276                                 Node *conversion = add_node(new GammaExpansionEffect());
1277                                 CHECK(conversion->effect->set_int("source_curve", node->output_gamma_curve));
1278                                 conversion->output_gamma_curve = GAMMA_LINEAR;
1279                                 connect_nodes(node, conversion);
1280                         }
1281
1282                         // If not, go through each input that is not linear gamma,
1283                         // and insert a gamma conversion after it.
1284                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
1285                                 Node *input = node->incoming_links[j];
1286                                 assert(input->output_gamma_curve != GAMMA_INVALID);
1287                                 if (input->output_gamma_curve == GAMMA_LINEAR) {
1288                                         continue;
1289                                 }
1290                                 Node *conversion = add_node(new GammaExpansionEffect());
1291                                 CHECK(conversion->effect->set_int("source_curve", input->output_gamma_curve));
1292                                 conversion->output_gamma_curve = GAMMA_LINEAR;
1293                                 replace_sender(input, conversion);
1294                                 connect_nodes(input, conversion);
1295                         }
1296
1297                         // Re-sort topologically, and propagate the new information.
1298                         propagate_alpha();
1299                         propagate_gamma_and_color_space();
1300
1301                         found_any = true;
1302                         break;
1303                 }
1304
1305                 char filename[256];
1306                 sprintf(filename, "step%u-gammafix-iter%u.dot", step, ++gamma_propagation_pass);
1307                 output_dot(filename);
1308                 assert(gamma_propagation_pass < 100);
1309         } while (found_any);
1310
1311         for (unsigned i = 0; i < nodes.size(); ++i) {
1312                 Node *node = nodes[i];
1313                 if (node->disabled) {
1314                         continue;
1315                 }
1316                 assert(node->output_gamma_curve != GAMMA_INVALID);
1317         }
1318 }
1319
1320 // Make so that the output is in the desired gamma.
1321 // Note that this assumes linear input gamma, so it might create the need
1322 // for another pass of fix_internal_gamma().
1323 void EffectChain::fix_output_gamma()
1324 {
1325         Node *output = find_output_node();
1326         if (output->output_gamma_curve != output_format.gamma_curve) {
1327                 Node *conversion = add_node(new GammaCompressionEffect());
1328                 CHECK(conversion->effect->set_int("destination_curve", output_format.gamma_curve));
1329                 conversion->output_gamma_curve = output_format.gamma_curve;
1330                 connect_nodes(output, conversion);
1331         }
1332 }
1333
1334 // If the user has requested dither, add a DitherEffect right at the end
1335 // (after GammaCompressionEffect etc.). This needs to be done after everything else,
1336 // since dither is about the only effect that can _not_ be done in linear space.
1337 void EffectChain::add_dither_if_needed()
1338 {
1339         if (num_dither_bits == 0) {
1340                 return;
1341         }
1342         Node *output = find_output_node();
1343         Node *dither = add_node(new DitherEffect());
1344         CHECK(dither->effect->set_int("num_bits", num_dither_bits));
1345         connect_nodes(output, dither);
1346
1347         dither_effect = dither->effect;
1348 }
1349
1350 // Find the output node. This is, simply, one that has no outgoing links.
1351 // If there are multiple ones, the graph is malformed (we do not support
1352 // multiple outputs right now).
1353 Node *EffectChain::find_output_node()
1354 {
1355         std::vector<Node *> output_nodes;
1356         for (unsigned i = 0; i < nodes.size(); ++i) {
1357                 Node *node = nodes[i];
1358                 if (node->disabled) {
1359                         continue;
1360                 }
1361                 if (node->outgoing_links.empty()) {
1362                         output_nodes.push_back(node);
1363                 }
1364         }
1365         assert(output_nodes.size() == 1);
1366         return output_nodes[0];
1367 }
1368
1369 void EffectChain::finalize()
1370 {
1371         // Save the current locale, and set it to C, so that we can output decimal
1372         // numbers with printf and be sure to get them in the format mandated by GLSL.
1373         char *saved_locale = setlocale(LC_NUMERIC, "C");
1374
1375         // Output the graph as it is before we do any conversions on it.
1376         output_dot("step0-start.dot");
1377
1378         // Give each effect in turn a chance to rewrite its own part of the graph.
1379         // Note that if more effects are added as part of this, they will be
1380         // picked up as part of the same for loop, since they are added at the end.
1381         for (unsigned i = 0; i < nodes.size(); ++i) {
1382                 nodes[i]->effect->rewrite_graph(this, nodes[i]);
1383         }
1384         output_dot("step1-rewritten.dot");
1385
1386         find_color_spaces_for_inputs();
1387         output_dot("step2-input-colorspace.dot");
1388
1389         propagate_alpha();
1390         output_dot("step3-propagated-alpha.dot");
1391
1392         propagate_gamma_and_color_space();
1393         output_dot("step4-propagated-all.dot");
1394
1395         fix_internal_color_spaces();
1396         fix_internal_alpha(6);
1397         fix_output_color_space();
1398         output_dot("step7-output-colorspacefix.dot");
1399         fix_output_alpha();
1400         output_dot("step8-output-alphafix.dot");
1401
1402         // Note that we need to fix gamma after colorspace conversion,
1403         // because colorspace conversions might create needs for gamma conversions.
1404         // Also, we need to run an extra pass of fix_internal_gamma() after
1405         // fixing the output gamma, as we only have conversions to/from linear,
1406         // and fix_internal_alpha() since GammaCompressionEffect needs
1407         // postmultiplied input.
1408         fix_internal_gamma_by_asking_inputs(9);
1409         fix_internal_gamma_by_inserting_nodes(10);
1410         fix_output_gamma();
1411         output_dot("step11-output-gammafix.dot");
1412         propagate_alpha();
1413         output_dot("step12-output-alpha-propagated.dot");
1414         fix_internal_alpha(13);
1415         output_dot("step14-output-alpha-fixed.dot");
1416         fix_internal_gamma_by_asking_inputs(15);
1417         fix_internal_gamma_by_inserting_nodes(16);
1418
1419         output_dot("step17-before-dither.dot");
1420
1421         add_dither_if_needed();
1422
1423         output_dot("step18-final.dot");
1424
1425         // Construct all needed GLSL programs, starting at the output.
1426         construct_glsl_programs(find_output_node());
1427
1428         output_dot("step19-split-to-phases.dot");
1429
1430         // If we have more than one phase, we need intermediate render-to-texture.
1431         // Construct an FBO, and then as many textures as we need.
1432         // We choose the simplest option of having one texture per output,
1433         // since otherwise this turns into an (albeit simple)
1434         // register allocation problem.
1435         if (phases.size() > 1) {
1436                 glGenFramebuffers(1, &fbo);
1437
1438                 for (unsigned i = 0; i < phases.size() - 1; ++i) {
1439                         inform_input_sizes(phases[i]);
1440                         find_output_size(phases[i]);
1441
1442                         Node *output_node = phases[i]->effects.back();
1443                         glGenTextures(1, &output_node->output_texture);
1444                         check_error();
1445                         glBindTexture(GL_TEXTURE_2D, output_node->output_texture);
1446                         check_error();
1447                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
1448                         check_error();
1449                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
1450                         check_error();
1451                         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F_ARB, phases[i]->output_width, phases[i]->output_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
1452                         check_error();
1453
1454                         output_node->output_texture_width = phases[i]->output_width;
1455                         output_node->output_texture_height = phases[i]->output_height;
1456                 }
1457                 inform_input_sizes(phases.back());
1458         }
1459
1460         for (unsigned i = 0; i < inputs.size(); ++i) {
1461                 inputs[i]->finalize();
1462         }
1463
1464         assert(phases[0]->inputs.empty());
1465
1466         finalized = true;
1467         setlocale(LC_NUMERIC, saved_locale);
1468 }
1469
1470 void EffectChain::render_to_fbo(GLuint dest_fbo, unsigned width, unsigned height)
1471 {
1472         assert(finalized);
1473
1474         // Save original viewport.
1475         GLuint x = 0, y = 0;
1476
1477         if (width == 0 && height == 0) {
1478                 GLint viewport[4];
1479                 glGetIntegerv(GL_VIEWPORT, viewport);
1480                 x = viewport[0];
1481                 y = viewport[1];
1482                 width = viewport[2];
1483                 height = viewport[3];
1484         }
1485
1486         // Basic state.
1487         glDisable(GL_BLEND);
1488         check_error();
1489         glDisable(GL_DEPTH_TEST);
1490         check_error();
1491         glDepthMask(GL_FALSE);
1492         check_error();
1493
1494         glMatrixMode(GL_PROJECTION);
1495         glLoadIdentity();
1496         glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
1497
1498         glMatrixMode(GL_MODELVIEW);
1499         glLoadIdentity();
1500
1501         if (phases.size() > 1) {
1502                 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
1503                 check_error();
1504         }
1505
1506         std::set<Node *> generated_mipmaps;
1507
1508         for (unsigned phase = 0; phase < phases.size(); ++phase) {
1509                 // See if the requested output size has changed. If so, we need to recreate
1510                 // the texture (and before we start setting up inputs).
1511                 inform_input_sizes(phases[phase]);
1512                 if (phase != phases.size() - 1) {
1513                         find_output_size(phases[phase]);
1514
1515                         Node *output_node = phases[phase]->effects.back();
1516
1517                         if (output_node->output_texture_width != phases[phase]->output_width ||
1518                             output_node->output_texture_height != phases[phase]->output_height) {
1519                                 glActiveTexture(GL_TEXTURE0);
1520                                 check_error();
1521                                 glBindTexture(GL_TEXTURE_2D, output_node->output_texture);
1522                                 check_error();
1523                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F_ARB, phases[phase]->output_width, phases[phase]->output_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
1524                                 check_error();
1525                                 glBindTexture(GL_TEXTURE_2D, 0);
1526                                 check_error();
1527
1528                                 output_node->output_texture_width = phases[phase]->output_width;
1529                                 output_node->output_texture_height = phases[phase]->output_height;
1530                         }
1531                 }
1532
1533                 glUseProgram(phases[phase]->glsl_program_num);
1534                 check_error();
1535
1536                 // Set up RTT inputs for this phase.
1537                 for (unsigned sampler = 0; sampler < phases[phase]->inputs.size(); ++sampler) {
1538                         glActiveTexture(GL_TEXTURE0 + sampler);
1539                         Node *input = phases[phase]->inputs[sampler];
1540                         glBindTexture(GL_TEXTURE_2D, input->output_texture);
1541                         check_error();
1542                         if (phases[phase]->input_needs_mipmaps) {
1543                                 if (generated_mipmaps.count(input) == 0) {
1544                                         glGenerateMipmap(GL_TEXTURE_2D);
1545                                         check_error();
1546                                         generated_mipmaps.insert(input);
1547                                 }
1548                                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
1549                                 check_error();
1550                         } else {
1551                                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
1552                                 check_error();
1553                         }
1554
1555                         std::string texture_name = std::string("tex_") + input->effect_id;
1556                         glUniform1i(glGetUniformLocation(phases[phase]->glsl_program_num, texture_name.c_str()), sampler);
1557                         check_error();
1558                 }
1559
1560                 // And now the output.
1561                 if (phase == phases.size() - 1) {
1562                         // Last phase goes to the output the user specified.
1563                         glBindFramebuffer(GL_FRAMEBUFFER, dest_fbo);
1564                         check_error();
1565                         GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
1566                         assert(status == GL_FRAMEBUFFER_COMPLETE);
1567                         glViewport(x, y, width, height);
1568                         if (dither_effect != NULL) {
1569                                 CHECK(dither_effect->set_int("output_width", width));
1570                                 CHECK(dither_effect->set_int("output_height", height));
1571                         }
1572                 } else {
1573                         Node *output_node = phases[phase]->effects.back();
1574                         glFramebufferTexture2D(
1575                                 GL_FRAMEBUFFER,
1576                                 GL_COLOR_ATTACHMENT0,
1577                                 GL_TEXTURE_2D,
1578                                 output_node->output_texture,
1579                                 0);
1580                         check_error();
1581                         GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
1582                         assert(status == GL_FRAMEBUFFER_COMPLETE);
1583                         glViewport(0, 0, phases[phase]->output_width, phases[phase]->output_height);
1584                 }
1585
1586                 // Give the required parameters to all the effects.
1587                 unsigned sampler_num = phases[phase]->inputs.size();
1588                 for (unsigned i = 0; i < phases[phase]->effects.size(); ++i) {
1589                         Node *node = phases[phase]->effects[i];
1590                         node->effect->set_gl_state(phases[phase]->glsl_program_num, node->effect_id, &sampler_num);
1591                         check_error();
1592                 }
1593
1594                 // Now draw!
1595                 glBegin(GL_QUADS);
1596
1597                 glTexCoord2f(0.0f, 0.0f);
1598                 glVertex2f(0.0f, 0.0f);
1599
1600                 glTexCoord2f(1.0f, 0.0f);
1601                 glVertex2f(1.0f, 0.0f);
1602
1603                 glTexCoord2f(1.0f, 1.0f);
1604                 glVertex2f(1.0f, 1.0f);
1605
1606                 glTexCoord2f(0.0f, 1.0f);
1607                 glVertex2f(0.0f, 1.0f);
1608
1609                 glEnd();
1610                 check_error();
1611
1612                 for (unsigned i = 0; i < phases[phase]->effects.size(); ++i) {
1613                         Node *node = phases[phase]->effects[i];
1614                         node->effect->clear_gl_state();
1615                 }
1616         }
1617 }