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 "resource_pool.h"
  27 #include "util.h"
  28
  29 EffectChain::EffectChain(float aspect_nom, float aspect_denom, ResourcePool *resource_pool)
  30         : aspect_nom(aspect_nom),
  31           aspect_denom(aspect_denom),
  32           dither_effect(NULL),
  33           num_dither_bits(0),
  34           finalized(false),
  35           resource_pool(resource_pool) {
  36         if (resource_pool == NULL) {
  37                 this->resource_pool = new ResourcePool();
  38                 owns_resource_pool = true;
  39         } else {
  40                 owns_resource_pool = false;
  41         }
  42 }
  43
  44 EffectChain::~EffectChain()
  45 {
  46         for (unsigned i = 0; i < nodes.size(); ++i) {
  47                 delete nodes[i]->effect;
  48                 delete nodes[i];
  49         }
  50         for (unsigned i = 0; i < phases.size(); ++i) {
  51                 resource_pool->release_glsl_program(phases[i]->glsl_program_num);
  52                 delete phases[i];
  53         }
  54         if (owns_resource_pool) {
  55                 delete resource_pool;
  56         }
  57 }
  58
  59 Input *EffectChain::add_input(Input *input)
  60 {
  61         assert(!finalized);
  62         inputs.push_back(input);
  63         add_node(input);
  64         return input;
  65 }
  66
  67 void EffectChain::add_output(const ImageFormat &format, OutputAlphaFormat alpha_format)
  68 {
  69         assert(!finalized);
  70         output_format = format;
  71         output_alpha_format = alpha_format;
  72 }
  73
  74 Node *EffectChain::add_node(Effect *effect)
  75 {
  76         for (unsigned i = 0; i < nodes.size(); ++i) {
  77                 assert(nodes[i]->effect != effect);
  78         }
  79
  80         Node *node = new Node;
  81         node->effect = effect;
  82         node->disabled = false;
  83         node->output_color_space = COLORSPACE_INVALID;
  84         node->output_gamma_curve = GAMMA_INVALID;
  85         node->output_alpha_type = ALPHA_INVALID;
  86
  87         nodes.push_back(node);
  88         node_map[effect] = node;
  89         effect->inform_added(this);
  90         return node;
  91 }
  92
  93 void EffectChain::connect_nodes(Node *sender, Node *receiver)
  94 {
  95         sender->outgoing_links.push_back(receiver);
  96         receiver->incoming_links.push_back(sender);
  97 }
  98
  99 void EffectChain::replace_receiver(Node *old_receiver, Node *new_receiver)
 100 {
 101         new_receiver->incoming_links = old_receiver->incoming_links;
 102         old_receiver->incoming_links.clear();
 103
 104         for (unsigned i = 0; i < new_receiver->incoming_links.size(); ++i) {
 105                 Node *sender = new_receiver->incoming_links[i];
 106                 for (unsigned j = 0; j < sender->outgoing_links.size(); ++j) {
 107                         if (sender->outgoing_links[j] == old_receiver) {
 108                                 sender->outgoing_links[j] = new_receiver;
 109                         }
 110                 }
 111         }
 112 }
 113
 114 void EffectChain::replace_sender(Node *old_sender, Node *new_sender)
 115 {
 116         new_sender->outgoing_links = old_sender->outgoing_links;
 117         old_sender->outgoing_links.clear();
 118
 119         for (unsigned i = 0; i < new_sender->outgoing_links.size(); ++i) {
 120                 Node *receiver = new_sender->outgoing_links[i];
 121                 for (unsigned j = 0; j < receiver->incoming_links.size(); ++j) {
 122                         if (receiver->incoming_links[j] == old_sender) {
 123                                 receiver->incoming_links[j] = new_sender;
 124                         }
 125                 }
 126         }
 127 }
 128
 129 void EffectChain::insert_node_between(Node *sender, Node *middle, Node *receiver)
 130 {
 131         for (unsigned i = 0; i < sender->outgoing_links.size(); ++i) {
 132                 if (sender->outgoing_links[i] == receiver) {
 133                         sender->outgoing_links[i] = middle;
 134                         middle->incoming_links.push_back(sender);
 135                 }
 136         }
 137         for (unsigned i = 0; i < receiver->incoming_links.size(); ++i) {
 138                 if (receiver->incoming_links[i] == sender) {
 139                         receiver->incoming_links[i] = middle;
 140                         middle->outgoing_links.push_back(receiver);
 141                 }
 142         }
 143
 144         assert(middle->incoming_links.size() == middle->effect->num_inputs());
 145 }
 146
 147 void EffectChain::find_all_nonlinear_inputs(Node *node, std::vector<Node *> *nonlinear_inputs)
 148 {
 149         if (node->output_gamma_curve == GAMMA_LINEAR &&
 150             node->effect->effect_type_id() != "GammaCompressionEffect") {
 151                 return;
 152         }
 153         if (node->effect->num_inputs() == 0) {
 154                 nonlinear_inputs->push_back(node);
 155         } else {
 156                 assert(node->effect->num_inputs() == node->incoming_links.size());
 157                 for (unsigned i = 0; i < node->incoming_links.size(); ++i) {
 158                         find_all_nonlinear_inputs(node->incoming_links[i], nonlinear_inputs);
 159                 }
 160         }
 161 }
 162
 163 Effect *EffectChain::add_effect(Effect *effect, const std::vector<Effect *> &inputs)
 164 {
 165         assert(!finalized);
 166         assert(inputs.size() == effect->num_inputs());
 167         Node *node = add_node(effect);
 168         for (unsigned i = 0; i < inputs.size(); ++i) {
 169                 assert(node_map.count(inputs[i]) != 0);
 170                 connect_nodes(node_map[inputs[i]], node);
 171         }
 172         return effect;
 173 }
 174
 175 // GLSL pre-1.30 doesn't support token pasting. Replace PREFIX(x) with <effect_id>_x.
 176 std::string replace_prefix(const std::string &text, const std::string &prefix)
 177 {
 178         std::string output;
 179         size_t start = 0;
 180
 181         while (start < text.size()) {
 182                 size_t pos = text.find("PREFIX(", start);
 183                 if (pos == std::string::npos) {
 184                         output.append(text.substr(start, std::string::npos));
 185                         break;
 186                 }
 187
 188                 output.append(text.substr(start, pos - start));
 189                 output.append(prefix);
 190                 output.append("_");
 191
 192                 pos += strlen("PREFIX(");
 193
 194                 // Output stuff until we find the matching ), which we then eat.
 195                 int depth = 1;
 196                 size_t end_arg_pos = pos;
 197                 while (end_arg_pos < text.size()) {
 198                         if (text[end_arg_pos] == '(') {
 199                                 ++depth;
 200                         } else if (text[end_arg_pos] == ')') {
 201                                 --depth;
 202                                 if (depth == 0) {
 203                                         break;
 204                                 }
 205                         }
 206                         ++end_arg_pos;
 207                 }
 208                 output.append(text.substr(pos, end_arg_pos - pos));
 209                 ++end_arg_pos;
 210                 assert(depth == 0);
 211                 start = end_arg_pos;
 212         }
 213         return output;
 214 }
 215
 216 Phase *EffectChain::compile_glsl_program(
 217         const std::vector<Node *> &inputs,
 218         const std::vector<Node *> &effects)
 219 {
 220         Phase *phase = new Phase;
 221         assert(!effects.empty());
 222
 223         // Deduplicate the inputs.
 224         std::vector<Node *> true_inputs = inputs;
 225         std::sort(true_inputs.begin(), true_inputs.end());
 226         true_inputs.erase(std::unique(true_inputs.begin(), true_inputs.end()), true_inputs.end());
 227
 228         bool input_needs_mipmaps = false;
 229         std::string frag_shader = read_file("header.frag");
 230
 231         // Create functions for all the texture inputs that we need.
 232         for (unsigned i = 0; i < true_inputs.size(); ++i) {
 233                 Node *input = true_inputs[i];
 234                 char effect_id[256];
 235                 sprintf(effect_id, "in%u", i);
 236                 phase->effect_ids.insert(std::make_pair(input, effect_id));
 237
 238                 frag_shader += std::string("uniform sampler2D tex_") + effect_id + ";\n";
 239                 frag_shader += std::string("vec4 ") + effect_id + "(vec2 tc) {\n";
 240                 frag_shader += "\treturn texture2D(tex_" + std::string(effect_id) + ", tc);\n";
 241                 frag_shader += "}\n";
 242                 frag_shader += "\n";
 243         }
 244
 245         std::vector<Node *> sorted_effects = topological_sort(effects);
 246
 247         for (unsigned i = 0; i < sorted_effects.size(); ++i) {
 248                 Node *node = sorted_effects[i];
 249                 char effect_id[256];
 250                 sprintf(effect_id, "eff%u", i);
 251                 phase->effect_ids.insert(std::make_pair(node, effect_id));
 252
 253                 if (node->incoming_links.size() == 1) {
 254                         frag_shader += std::string("#define INPUT ") + phase->effect_ids[node->incoming_links[0]] + "\n";
 255                 } else {
 256                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 257                                 char buf[256];
 258                                 sprintf(buf, "#define INPUT%d %s\n", j + 1, phase->effect_ids[node->incoming_links[j]].c_str());
 259                                 frag_shader += buf;
 260                         }
 261                 }
 262
 263                 frag_shader += "\n";
 264                 frag_shader += std::string("#define FUNCNAME ") + effect_id + "\n";
 265                 frag_shader += replace_prefix(node->effect->output_convenience_uniforms(), effect_id);
 266                 frag_shader += replace_prefix(node->effect->output_fragment_shader(), effect_id);
 267                 frag_shader += "#undef PREFIX\n";
 268                 frag_shader += "#undef FUNCNAME\n";
 269                 if (node->incoming_links.size() == 1) {
 270                         frag_shader += "#undef INPUT\n";
 271                 } else {
 272                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 273                                 char buf[256];
 274                                 sprintf(buf, "#undef INPUT%d\n", j + 1);
 275                                 frag_shader += buf;
 276                         }
 277                 }
 278                 frag_shader += "\n";
 279
 280                 input_needs_mipmaps |= node->effect->needs_mipmaps();
 281         }
 282         for (unsigned i = 0; i < sorted_effects.size(); ++i) {
 283                 Node *node = sorted_effects[i];
 284                 if (node->effect->num_inputs() == 0) {
 285                         CHECK(node->effect->set_int("needs_mipmaps", input_needs_mipmaps));
 286                 }
 287         }
 288         frag_shader += std::string("#define INPUT ") + phase->effect_ids[sorted_effects.back()] + "\n";
 289         frag_shader.append(read_file("footer.frag"));
 290
 291         phase->glsl_program_num = resource_pool->compile_glsl_program(read_file("vs.vert"), frag_shader);
 292         phase->input_needs_mipmaps = input_needs_mipmaps;
 293         phase->inputs = true_inputs;
 294         phase->effects = sorted_effects;
 295
 296         return phase;
 297 }
 298
 299 // Construct GLSL programs, starting at the given effect and following
 300 // the chain from there. We end a program every time we come to an effect
 301 // marked as "needs texture bounce", one that is used by multiple other
 302 // effects, every time an effect wants to change the output size,
 303 // and of course at the end.
 304 //
 305 // We follow a quite simple depth-first search from the output, although
 306 // without any explicit recursion.
 307 void EffectChain::construct_glsl_programs(Node *output)
 308 {
 309         // Which effects have already been completed?
 310         // We need to keep track of it, as an effect with multiple outputs
 311         // could otherwise be calculated multiple times.
 312         std::set<Node *> completed_effects;
 313
 314         // Effects in the current phase, as well as inputs (outputs from other phases
 315         // that we depend on). Note that since we start iterating from the end,
 316         // the effect list will be in the reverse order.
 317         std::vector<Node *> this_phase_inputs;
 318         std::vector<Node *> this_phase_effects;
 319
 320         // Effects that we have yet to calculate, but that we know should
 321         // be in the current phase.
 322         std::stack<Node *> effects_todo_this_phase;
 323
 324         // Effects that we have yet to calculate, but that come from other phases.
 325         // We delay these until we have this phase done in its entirety,
 326         // at which point we pick any of them and start a new phase from that.
 327         std::stack<Node *> effects_todo_other_phases;
 328
 329         effects_todo_this_phase.push(output);
 330
 331         for ( ;; ) {  // Termination condition within loop.
 332                 if (!effects_todo_this_phase.empty()) {
 333                         // OK, we have more to do this phase.
 334                         Node *node = effects_todo_this_phase.top();
 335                         effects_todo_this_phase.pop();
 336
 337                         // This should currently only happen for effects that are inputs
 338                         // (either true inputs or phase outputs). We special-case inputs,
 339                         // and then deduplicate phase outputs in compile_glsl_program().
 340                         if (node->effect->num_inputs() == 0) {
 341                                 if (find(this_phase_effects.begin(), this_phase_effects.end(), node) != this_phase_effects.end()) {
 342                                         continue;
 343                                 }
 344                         } else {
 345                                 assert(completed_effects.count(node) == 0);
 346                         }
 347
 348                         this_phase_effects.push_back(node);
 349                         completed_effects.insert(node);
 350
 351                         // Find all the dependencies of this effect, and add them to the stack.
 352                         std::vector<Node *> deps = node->incoming_links;
 353                         assert(node->effect->num_inputs() == deps.size());
 354                         for (unsigned i = 0; i < deps.size(); ++i) {
 355                                 bool start_new_phase = false;
 356
 357                                 // FIXME: If we sample directly from a texture, we won't need this.
 358                                 if (node->effect->needs_texture_bounce()) {
 359                                         start_new_phase = true;
 360                                 }
 361
 362                                 if (deps[i]->outgoing_links.size() > 1) {
 363                                         if (deps[i]->effect->num_inputs() > 0) {
 364                                                 // More than one effect uses this as the input,
 365                                                 // and it is not a texture itself.
 366                                                 // The easiest thing to do (and probably also the safest
 367                                                 // performance-wise in most cases) is to bounce it to a texture
 368                                                 // and then let the next passes read from that.
 369                                                 start_new_phase = true;
 370                                         } else {
 371                                                 // For textures, we try to be slightly more clever;
 372                                                 // if none of our outputs need a bounce, we don't bounce
 373                                                 // but instead simply use the effect many times.
 374                                                 //
 375                                                 // Strictly speaking, we could bounce it for some outputs
 376                                                 // and use it directly for others, but the processing becomes
 377                                                 // somewhat simpler if the effect is only used in one such way.
 378                                                 for (unsigned j = 0; j < deps[i]->outgoing_links.size(); ++j) {
 379                                                         Node *rdep = deps[i]->outgoing_links[j];
 380                                                         start_new_phase |= rdep->effect->needs_texture_bounce();
 381                                                 }
 382                                         }
 383                                 }
 384
 385                                 if (deps[i]->effect->changes_output_size()) {
 386                                         start_new_phase = true;
 387                                 }
 388
 389                                 if (start_new_phase) {
 390                                         effects_todo_other_phases.push(deps[i]);
 391                                         this_phase_inputs.push_back(deps[i]);
 392                                 } else {
 393                                         effects_todo_this_phase.push(deps[i]);
 394                                 }
 395                         }
 396                         continue;
 397                 }
 398
 399                 // No more effects to do this phase. Take all the ones we have,
 400                 // and create a GLSL program for it.
 401                 if (!this_phase_effects.empty()) {
 402                         reverse(this_phase_effects.begin(), this_phase_effects.end());
 403                         phases.push_back(compile_glsl_program(this_phase_inputs, this_phase_effects));
 404                         this_phase_effects.back()->phase = phases.back();
 405                         this_phase_inputs.clear();
 406                         this_phase_effects.clear();
 407                 }
 408                 assert(this_phase_inputs.empty());
 409                 assert(this_phase_effects.empty());
 410
 411                 // If we have no effects left, exit.
 412                 if (effects_todo_other_phases.empty()) {
 413                         break;
 414                 }
 415
 416                 Node *node = effects_todo_other_phases.top();
 417                 effects_todo_other_phases.pop();
 418
 419                 if (completed_effects.count(node) == 0) {
 420                         // Start a new phase, calculating from this effect.
 421                         effects_todo_this_phase.push(node);
 422                 }
 423         }
 424
 425         // Finally, since the phases are found from the output but must be executed
 426         // from the input(s), reverse them, too.
 427         std::reverse(phases.begin(), phases.end());
 428 }
 429
 430 void EffectChain::output_dot(const char *filename)
 431 {
 432         if (movit_debug_level != MOVIT_DEBUG_ON) {
 433                 return;
 434         }
 435
 436         FILE *fp = fopen(filename, "w");
 437         if (fp == NULL) {
 438                 perror(filename);
 439                 exit(1);
 440         }
 441
 442         fprintf(fp, "digraph G {\n");
 443         fprintf(fp, "  output [shape=box label=\"(output)\"];\n");
 444         for (unsigned i = 0; i < nodes.size(); ++i) {
 445                 // Find out which phase this event belongs to.
 446                 std::vector<int> in_phases;
 447                 for (unsigned j = 0; j < phases.size(); ++j) {
 448                         const Phase* p = phases[j];
 449                         if (std::find(p->effects.begin(), p->effects.end(), nodes[i]) != p->effects.end()) {
 450                                 in_phases.push_back(j);
 451                         }
 452                 }
 453
 454                 if (in_phases.empty()) {
 455                         fprintf(fp, "  n%ld [label=\"%s\"];\n", (long)nodes[i], nodes[i]->effect->effect_type_id().c_str());
 456                 } else if (in_phases.size() == 1) {
 457                         fprintf(fp, "  n%ld [label=\"%s\" style=\"filled\" fillcolor=\"/accent8/%d\"];\n",
 458                                 (long)nodes[i], nodes[i]->effect->effect_type_id().c_str(),
 459                                 (in_phases[0] % 8) + 1);
 460                 } else {
 461                         // If we had new enough Graphviz, style="wedged" would probably be ideal here.
 462                         // But alas.
 463                         fprintf(fp, "  n%ld [label=\"%s [in multiple phases]\" style=\"filled\" fillcolor=\"/accent8/%d\"];\n",
 464                                 (long)nodes[i], nodes[i]->effect->effect_type_id().c_str(),
 465                                 (in_phases[0] % 8) + 1);
 466                 }
 467
 468                 char from_node_id[256];
 469                 snprintf(from_node_id, 256, "n%ld", (long)nodes[i]);
 470
 471                 for (unsigned j = 0; j < nodes[i]->outgoing_links.size(); ++j) {
 472                         char to_node_id[256];
 473                         snprintf(to_node_id, 256, "n%ld", (long)nodes[i]->outgoing_links[j]);
 474
 475                         std::vector<std::string> labels = get_labels_for_edge(nodes[i], nodes[i]->outgoing_links[j]);
 476                         output_dot_edge(fp, from_node_id, to_node_id, labels);
 477                 }
 478
 479                 if (nodes[i]->outgoing_links.empty() && !nodes[i]->disabled) {
 480                         // Output node.
 481                         std::vector<std::string> labels = get_labels_for_edge(nodes[i], NULL);
 482                         output_dot_edge(fp, from_node_id, "output", labels);
 483                 }
 484         }
 485         fprintf(fp, "}\n");
 486
 487         fclose(fp);
 488 }
 489
 490 std::vector<std::string> EffectChain::get_labels_for_edge(const Node *from, const Node *to)
 491 {
 492         std::vector<std::string> labels;
 493
 494         if (to != NULL && to->effect->needs_texture_bounce()) {
 495                 labels.push_back("needs_bounce");
 496         }
 497         if (from->effect->changes_output_size()) {
 498                 labels.push_back("resize");
 499         }
 500
 501         switch (from->output_color_space) {
 502         case COLORSPACE_INVALID:
 503                 labels.push_back("spc[invalid]");
 504                 break;
 505         case COLORSPACE_REC_601_525:
 506                 labels.push_back("spc[rec601-525]");
 507                 break;
 508         case COLORSPACE_REC_601_625:
 509                 labels.push_back("spc[rec601-625]");
 510                 break;
 511         default:
 512                 break;
 513         }
 514
 515         switch (from->output_gamma_curve) {
 516         case GAMMA_INVALID:
 517                 labels.push_back("gamma[invalid]");
 518                 break;
 519         case GAMMA_sRGB:
 520                 labels.push_back("gamma[sRGB]");
 521                 break;
 522         case GAMMA_REC_601:  // and GAMMA_REC_709
 523                 labels.push_back("gamma[rec601/709]");
 524                 break;
 525         default:
 526                 break;
 527         }
 528
 529         switch (from->output_alpha_type) {
 530         case ALPHA_INVALID:
 531                 labels.push_back("alpha[invalid]");
 532                 break;
 533         case ALPHA_BLANK:
 534                 labels.push_back("alpha[blank]");
 535                 break;
 536         case ALPHA_POSTMULTIPLIED:
 537                 labels.push_back("alpha[postmult]");
 538                 break;
 539         default:
 540                 break;
 541         }
 542
 543         return labels;
 544 }
 545
 546 void EffectChain::output_dot_edge(FILE *fp,
 547                                   const std::string &from_node_id,
 548                                   const std::string &to_node_id,
 549                                   const std::vector<std::string> &labels)
 550 {
 551         if (labels.empty()) {
 552                 fprintf(fp, "  %s -> %s;\n", from_node_id.c_str(), to_node_id.c_str());
 553         } else {
 554                 std::string label = labels[0];
 555                 for (unsigned k = 1; k < labels.size(); ++k) {
 556                         label += ", " + labels[k];
 557                 }
 558                 fprintf(fp, "  %s -> %s [label=\"%s\"];\n", from_node_id.c_str(), to_node_id.c_str(), label.c_str());
 559         }
 560 }
 561
 562 void EffectChain::size_rectangle_to_fit(unsigned width, unsigned height, unsigned *output_width, unsigned *output_height)
 563 {
 564         unsigned scaled_width, scaled_height;
 565
 566         if (float(width) * aspect_denom >= float(height) * aspect_nom) {
 567                 // Same aspect, or W/H > aspect (image is wider than the frame).
 568                 // In either case, keep width, and adjust height.
 569                 scaled_width = width;
 570                 scaled_height = lrintf(width * aspect_denom / aspect_nom);
 571         } else {
 572                 // W/H < aspect (image is taller than the frame), so keep height,
 573                 // and adjust width.
 574                 scaled_width = lrintf(height * aspect_nom / aspect_denom);
 575                 scaled_height = height;
 576         }
 577
 578         // We should be consistently larger or smaller then the existing choice,
 579         // since we have the same aspect.
 580         assert(!(scaled_width < *output_width && scaled_height > *output_height));
 581         assert(!(scaled_height < *output_height && scaled_width > *output_width));
 582
 583         if (scaled_width >= *output_width && scaled_height >= *output_height) {
 584                 *output_width = scaled_width;
 585                 *output_height = scaled_height;
 586         }
 587 }
 588
 589 // Propagate input texture sizes throughout, and inform effects downstream.
 590 // (Like a lot of other code, we depend on effects being in topological order.)
 591 void EffectChain::inform_input_sizes(Phase *phase)
 592 {
 593         // All effects that have a defined size (inputs and RTT inputs)
 594         // get that. Reset all others.
 595         for (unsigned i = 0; i < phase->effects.size(); ++i) {
 596                 Node *node = phase->effects[i];
 597                 if (node->effect->num_inputs() == 0) {
 598                         Input *input = static_cast<Input *>(node->effect);
 599                         node->output_width = input->get_width();
 600                         node->output_height = input->get_height();
 601                         assert(node->output_width != 0);
 602                         assert(node->output_height != 0);
 603                 } else {
 604                         node->output_width = node->output_height = 0;
 605                 }
 606         }
 607         for (unsigned i = 0; i < phase->inputs.size(); ++i) {
 608                 Node *input = phase->inputs[i];
 609                 input->output_width = input->phase->virtual_output_width;
 610                 input->output_height = input->phase->virtual_output_height;
 611                 assert(input->output_width != 0);
 612                 assert(input->output_height != 0);
 613         }
 614
 615         // Now propagate from the inputs towards the end, and inform as we go.
 616         // The rules are simple:
 617         //
 618         //   1. Don't touch effects that already have given sizes (ie., inputs).
 619         //   2. If all of your inputs have the same size, that will be your output size.
 620         //   3. Otherwise, your output size is 0x0.
 621         for (unsigned i = 0; i < phase->effects.size(); ++i) {
 622                 Node *node = phase->effects[i];
 623                 if (node->effect->num_inputs() == 0) {
 624                         continue;
 625                 }
 626                 unsigned this_output_width = 0;
 627                 unsigned this_output_height = 0;
 628                 for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 629                         Node *input = node->incoming_links[j];
 630                         node->effect->inform_input_size(j, input->output_width, input->output_height);
 631                         if (j == 0) {
 632                                 this_output_width = input->output_width;
 633                                 this_output_height = input->output_height;
 634                         } else if (input->output_width != this_output_width || input->output_height != this_output_height) {
 635                                 // Inputs disagree.
 636                                 this_output_width = 0;
 637                                 this_output_height = 0;
 638                         }
 639                 }
 640                 node->output_width = this_output_width;
 641                 node->output_height = this_output_height;
 642         }
 643 }
 644
 645 // Note: You should call inform_input_sizes() before this, as the last effect's
 646 // desired output size might change based on the inputs.
 647 void EffectChain::find_output_size(Phase *phase)
 648 {
 649         Node *output_node = phase->effects.back();
 650
 651         // If the last effect explicitly sets an output size, use that.
 652         if (output_node->effect->changes_output_size()) {
 653                 output_node->effect->get_output_size(&phase->output_width, &phase->output_height,
 654                                                      &phase->virtual_output_width, &phase->virtual_output_height);
 655                 return;
 656         }
 657
 658         // If all effects have the same size, use that.
 659         unsigned output_width = 0, output_height = 0;
 660         bool all_inputs_same_size = true;
 661
 662         for (unsigned i = 0; i < phase->inputs.size(); ++i) {
 663                 Node *input = phase->inputs[i];
 664                 assert(input->phase->output_width != 0);
 665                 assert(input->phase->output_height != 0);
 666                 if (output_width == 0 && output_height == 0) {
 667                         output_width = input->phase->virtual_output_width;
 668                         output_height = input->phase->virtual_output_height;
 669                 } else if (output_width != input->phase->virtual_output_width ||
 670                            output_height != input->phase->virtual_output_height) {
 671                         all_inputs_same_size = false;
 672                 }
 673         }
 674         for (unsigned i = 0; i < phase->effects.size(); ++i) {
 675                 Effect *effect = phase->effects[i]->effect;
 676                 if (effect->num_inputs() != 0) {
 677                         continue;
 678                 }
 679
 680                 Input *input = static_cast<Input *>(effect);
 681                 if (output_width == 0 && output_height == 0) {
 682                         output_width = input->get_width();
 683                         output_height = input->get_height();
 684                 } else if (output_width != input->get_width() ||
 685                            output_height != input->get_height()) {
 686                         all_inputs_same_size = false;
 687                 }
 688         }
 689
 690         if (all_inputs_same_size) {
 691                 assert(output_width != 0);
 692                 assert(output_height != 0);
 693                 phase->virtual_output_width = phase->output_width = output_width;
 694                 phase->virtual_output_height = phase->output_height = output_height;
 695                 return;
 696         }
 697
 698         // If not, fit all the inputs into the current aspect, and select the largest one.
 699         output_width = 0;
 700         output_height = 0;
 701         for (unsigned i = 0; i < phase->inputs.size(); ++i) {
 702                 Node *input = phase->inputs[i];
 703                 assert(input->phase->output_width != 0);
 704                 assert(input->phase->output_height != 0);
 705                 size_rectangle_to_fit(input->phase->output_width, input->phase->output_height, &output_width, &output_height);
 706         }
 707         for (unsigned i = 0; i < phase->effects.size(); ++i) {
 708                 Effect *effect = phase->effects[i]->effect;
 709                 if (effect->num_inputs() != 0) {
 710                         continue;
 711                 }
 712
 713                 Input *input = static_cast<Input *>(effect);
 714                 size_rectangle_to_fit(input->get_width(), input->get_height(), &output_width, &output_height);
 715         }
 716         assert(output_width != 0);
 717         assert(output_height != 0);
 718         phase->virtual_output_width = phase->output_width = output_width;
 719         phase->virtual_output_height = phase->output_height = output_height;
 720 }
 721
 722 void EffectChain::sort_all_nodes_topologically()
 723 {
 724         nodes = topological_sort(nodes);
 725 }
 726
 727 std::vector<Node *> EffectChain::topological_sort(const std::vector<Node *> &nodes)
 728 {
 729         std::set<Node *> nodes_left_to_visit(nodes.begin(), nodes.end());
 730         std::vector<Node *> sorted_list;
 731         for (unsigned i = 0; i < nodes.size(); ++i) {
 732                 topological_sort_visit_node(nodes[i], &nodes_left_to_visit, &sorted_list);
 733         }
 734         reverse(sorted_list.begin(), sorted_list.end());
 735         return sorted_list;
 736 }
 737
 738 void EffectChain::topological_sort_visit_node(Node *node, std::set<Node *> *nodes_left_to_visit, std::vector<Node *> *sorted_list)
 739 {
 740         if (nodes_left_to_visit->count(node) == 0) {
 741                 return;
 742         }
 743         nodes_left_to_visit->erase(node);
 744         for (unsigned i = 0; i < node->outgoing_links.size(); ++i) {
 745                 topological_sort_visit_node(node->outgoing_links[i], nodes_left_to_visit, sorted_list);
 746         }
 747         sorted_list->push_back(node);
 748 }
 749
 750 void EffectChain::find_color_spaces_for_inputs()
 751 {
 752         for (unsigned i = 0; i < nodes.size(); ++i) {
 753                 Node *node = nodes[i];
 754                 if (node->disabled) {
 755                         continue;
 756                 }
 757                 if (node->incoming_links.size() == 0) {
 758                         Input *input = static_cast<Input *>(node->effect);
 759                         node->output_color_space = input->get_color_space();
 760                         node->output_gamma_curve = input->get_gamma_curve();
 761
 762                         Effect::AlphaHandling alpha_handling = input->alpha_handling();
 763                         switch (alpha_handling) {
 764                         case Effect::OUTPUT_BLANK_ALPHA:
 765                                 node->output_alpha_type = ALPHA_BLANK;
 766                                 break;
 767                         case Effect::INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA:
 768                                 node->output_alpha_type = ALPHA_PREMULTIPLIED;
 769                                 break;
 770                         case Effect::OUTPUT_POSTMULTIPLIED_ALPHA:
 771                                 node->output_alpha_type = ALPHA_POSTMULTIPLIED;
 772                                 break;
 773                         case Effect::INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK:
 774                         case Effect::DONT_CARE_ALPHA_TYPE:
 775                         default:
 776                                 assert(false);
 777                         }
 778
 779                         if (node->output_alpha_type == ALPHA_PREMULTIPLIED) {
 780                                 assert(node->output_gamma_curve == GAMMA_LINEAR);
 781                         }
 782                 }
 783         }
 784 }
 785
 786 // Propagate gamma and color space information as far as we can in the graph.
 787 // The rules are simple: Anything where all the inputs agree, get that as
 788 // output as well. Anything else keeps having *_INVALID.
 789 void EffectChain::propagate_gamma_and_color_space()
 790 {
 791         // We depend on going through the nodes in order.
 792         sort_all_nodes_topologically();
 793
 794         for (unsigned i = 0; i < nodes.size(); ++i) {
 795                 Node *node = nodes[i];
 796                 if (node->disabled) {
 797                         continue;
 798                 }
 799                 assert(node->incoming_links.size() == node->effect->num_inputs());
 800                 if (node->incoming_links.size() == 0) {
 801                         assert(node->output_color_space != COLORSPACE_INVALID);
 802                         assert(node->output_gamma_curve != GAMMA_INVALID);
 803                         continue;
 804                 }
 805
 806                 Colorspace color_space = node->incoming_links[0]->output_color_space;
 807                 GammaCurve gamma_curve = node->incoming_links[0]->output_gamma_curve;
 808                 for (unsigned j = 1; j < node->incoming_links.size(); ++j) {
 809                         if (node->incoming_links[j]->output_color_space != color_space) {
 810                                 color_space = COLORSPACE_INVALID;
 811                         }
 812                         if (node->incoming_links[j]->output_gamma_curve != gamma_curve) {
 813                                 gamma_curve = GAMMA_INVALID;
 814                         }
 815                 }
 816
 817                 // The conversion effects already have their outputs set correctly,
 818                 // so leave them alone.
 819                 if (node->effect->effect_type_id() != "ColorspaceConversionEffect") {
 820                         node->output_color_space = color_space;
 821                 }
 822                 if (node->effect->effect_type_id() != "GammaCompressionEffect" &&
 823                     node->effect->effect_type_id() != "GammaExpansionEffect") {
 824                         node->output_gamma_curve = gamma_curve;
 825                 }
 826         }
 827 }
 828
 829 // Propagate alpha information as far as we can in the graph.
 830 // Similar to propagate_gamma_and_color_space().
 831 void EffectChain::propagate_alpha()
 832 {
 833         // We depend on going through the nodes in order.
 834         sort_all_nodes_topologically();
 835
 836         for (unsigned i = 0; i < nodes.size(); ++i) {
 837                 Node *node = nodes[i];
 838                 if (node->disabled) {
 839                         continue;
 840                 }
 841                 assert(node->incoming_links.size() == node->effect->num_inputs());
 842                 if (node->incoming_links.size() == 0) {
 843                         assert(node->output_alpha_type != ALPHA_INVALID);
 844                         continue;
 845                 }
 846
 847                 // The alpha multiplication/division effects are special cases.
 848                 if (node->effect->effect_type_id() == "AlphaMultiplicationEffect") {
 849                         assert(node->incoming_links.size() == 1);
 850                         assert(node->incoming_links[0]->output_alpha_type == ALPHA_POSTMULTIPLIED);
 851                         node->output_alpha_type = ALPHA_PREMULTIPLIED;
 852                         continue;
 853                 }
 854                 if (node->effect->effect_type_id() == "AlphaDivisionEffect") {
 855                         assert(node->incoming_links.size() == 1);
 856                         assert(node->incoming_links[0]->output_alpha_type == ALPHA_PREMULTIPLIED);
 857                         node->output_alpha_type = ALPHA_POSTMULTIPLIED;
 858                         continue;
 859                 }
 860
 861                 // GammaCompressionEffect and GammaExpansionEffect are also a special case,
 862                 // because they are the only one that _need_ postmultiplied alpha.
 863                 if (node->effect->effect_type_id() == "GammaCompressionEffect" ||
 864                     node->effect->effect_type_id() == "GammaExpansionEffect") {
 865                         assert(node->incoming_links.size() == 1);
 866                         if (node->incoming_links[0]->output_alpha_type == ALPHA_BLANK) {
 867                                 node->output_alpha_type = ALPHA_BLANK;
 868                         } else if (node->incoming_links[0]->output_alpha_type == ALPHA_POSTMULTIPLIED) {
 869                                 node->output_alpha_type = ALPHA_POSTMULTIPLIED;
 870                         } else {
 871                                 node->output_alpha_type = ALPHA_INVALID;
 872                         }
 873                         continue;
 874                 }
 875
 876                 // Only inputs can have unconditional alpha output (OUTPUT_BLANK_ALPHA
 877                 // or OUTPUT_POSTMULTIPLIED_ALPHA), and they have already been
 878                 // taken care of above. Rationale: Even if you could imagine
 879                 // e.g. an effect that took in an image and set alpha=1.0
 880                 // unconditionally, it wouldn't make any sense to have it as
 881                 // e.g. OUTPUT_BLANK_ALPHA, since it wouldn't know whether it
 882                 // got its input pre- or postmultiplied, so it wouldn't know
 883                 // whether to divide away the old alpha or not.
 884                 Effect::AlphaHandling alpha_handling = node->effect->alpha_handling();
 885                 assert(alpha_handling == Effect::INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA ||
 886                        alpha_handling == Effect::INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK ||
 887                        alpha_handling == Effect::DONT_CARE_ALPHA_TYPE);
 888
 889                 // If the node has multiple inputs, check that they are all valid and
 890                 // the same.
 891                 bool any_invalid = false;
 892                 bool any_premultiplied = false;
 893                 bool any_postmultiplied = false;
 894
 895                 for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 896                         switch (node->incoming_links[j]->output_alpha_type) {
 897                         case ALPHA_INVALID:
 898                                 any_invalid = true;
 899                                 break;
 900                         case ALPHA_BLANK:
 901                                 // Blank is good as both pre- and postmultiplied alpha,
 902                                 // so just ignore it.
 903                                 break;
 904                         case ALPHA_PREMULTIPLIED:
 905                                 any_premultiplied = true;
 906                                 break;
 907                         case ALPHA_POSTMULTIPLIED:
 908                                 any_postmultiplied = true;
 909                                 break;
 910                         default:
 911                                 assert(false);
 912                         }
 913                 }
 914
 915                 if (any_invalid) {
 916                         node->output_alpha_type = ALPHA_INVALID;
 917                         continue;
 918                 }
 919
 920                 // Inputs must be of the same type.
 921                 if (any_premultiplied && any_postmultiplied) {
 922                         node->output_alpha_type = ALPHA_INVALID;
 923                         continue;
 924                 }
 925
 926                 if (alpha_handling == Effect::INPUT_AND_OUTPUT_PREMULTIPLIED_ALPHA ||
 927                     alpha_handling == Effect::INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK) {
 928                         // If the effect has asked for premultiplied alpha, check that it has got it.
 929                         if (any_postmultiplied) {
 930                                 node->output_alpha_type = ALPHA_INVALID;
 931                         } else if (!any_premultiplied &&
 932                                    alpha_handling == Effect::INPUT_PREMULTIPLIED_ALPHA_KEEP_BLANK) {
 933                                 // Blank input alpha, and the effect preserves blank alpha.
 934                                 node->output_alpha_type = ALPHA_BLANK;
 935                         } else {
 936                                 node->output_alpha_type = ALPHA_PREMULTIPLIED;
 937                         }
 938                 } else {
 939                         // OK, all inputs are the same, and this effect is not going
 940                         // to change it.
 941                         assert(alpha_handling == Effect::DONT_CARE_ALPHA_TYPE);
 942                         if (any_premultiplied) {
 943                                 node->output_alpha_type = ALPHA_PREMULTIPLIED;
 944                         } else if (any_postmultiplied) {
 945                                 node->output_alpha_type = ALPHA_POSTMULTIPLIED;
 946                         } else {
 947                                 node->output_alpha_type = ALPHA_BLANK;
 948                         }
 949                 }
 950         }
 951 }
 952
 953 bool EffectChain::node_needs_colorspace_fix(Node *node)
 954 {
 955         if (node->disabled) {
 956                 return false;
 957         }
 958         if (node->effect->num_inputs() == 0) {
 959                 return false;
 960         }
 961
 962         // propagate_gamma_and_color_space() has already set our output
 963         // to COLORSPACE_INVALID if the inputs differ, so we can rely on that.
 964         if (node->output_color_space == COLORSPACE_INVALID) {
 965                 return true;
 966         }
 967         return (node->effect->needs_srgb_primaries() && node->output_color_space != COLORSPACE_sRGB);
 968 }
 969
 970 // Fix up color spaces so that there are no COLORSPACE_INVALID nodes left in
 971 // the graph. Our strategy is not always optimal, but quite simple:
 972 // Find an effect that's as early as possible where the inputs are of
 973 // unacceptable colorspaces (that is, either different, or, if the effect only
 974 // wants sRGB, not sRGB.) Add appropriate conversions on all its inputs,
 975 // propagate the information anew, and repeat until there are no more such
 976 // effects.
 977 void EffectChain::fix_internal_color_spaces()
 978 {
 979         unsigned colorspace_propagation_pass = 0;
 980         bool found_any;
 981         do {
 982                 found_any = false;
 983                 for (unsigned i = 0; i < nodes.size(); ++i) {
 984                         Node *node = nodes[i];
 985                         if (!node_needs_colorspace_fix(node)) {
 986                                 continue;
 987                         }
 988
 989                         // Go through each input that is not sRGB, and insert
 990                         // a colorspace conversion after it.
 991                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 992                                 Node *input = node->incoming_links[j];
 993                                 assert(input->output_color_space != COLORSPACE_INVALID);
 994                                 if (input->output_color_space == COLORSPACE_sRGB) {
 995                                         continue;
 996                                 }
 997                                 Node *conversion = add_node(new ColorspaceConversionEffect());
 998                                 CHECK(conversion->effect->set_int("source_space", input->output_color_space));
 999                                 CHECK(conversion->effect->set_int("destination_space", COLORSPACE_sRGB));
1000                                 conversion->output_color_space = COLORSPACE_sRGB;
1001                                 replace_sender(input, conversion);
1002                                 connect_nodes(input, conversion);
1003                         }
1004
1005                         // Re-sort topologically, and propagate the new information.
1006                         propagate_gamma_and_color_space();
1007
1008                         found_any = true;
1009                         break;
1010                 }
1011
1012                 char filename[256];
1013                 sprintf(filename, "step5-colorspacefix-iter%u.dot", ++colorspace_propagation_pass);
1014                 output_dot(filename);
1015                 assert(colorspace_propagation_pass < 100);
1016         } while (found_any);
1017
1018         for (unsigned i = 0; i < nodes.size(); ++i) {
1019                 Node *node = nodes[i];
1020                 if (node->disabled) {
1021                         continue;
1022                 }
1023                 assert(node->output_color_space != COLORSPACE_INVALID);
1024         }
1025 }
1026
1027 bool EffectChain::node_needs_alpha_fix(Node *node)
1028 {
1029         if (node->disabled) {
1030                 return false;
1031         }
1032
1033         // propagate_alpha() has already set our output to ALPHA_INVALID if the
1034         // inputs differ or we are otherwise in mismatch, so we can rely on that.
1035         return (node->output_alpha_type == ALPHA_INVALID);
1036 }
1037
1038 // Fix up alpha so that there are no ALPHA_INVALID nodes left in
1039 // the graph. Similar to fix_internal_color_spaces().
1040 void EffectChain::fix_internal_alpha(unsigned step)
1041 {
1042         unsigned alpha_propagation_pass = 0;
1043         bool found_any;
1044         do {
1045                 found_any = false;
1046                 for (unsigned i = 0; i < nodes.size(); ++i) {
1047                         Node *node = nodes[i];
1048                         if (!node_needs_alpha_fix(node)) {
1049                                 continue;
1050                         }
1051
1052                         // If we need to fix up GammaExpansionEffect, then clearly something
1053                         // is wrong, since the combination of premultiplied alpha and nonlinear inputs
1054                         // is meaningless.
1055                         assert(node->effect->effect_type_id() != "GammaExpansionEffect");
1056
1057                         AlphaType desired_type = ALPHA_PREMULTIPLIED;
1058
1059                         // GammaCompressionEffect is special; it needs postmultiplied alpha.
1060                         if (node->effect->effect_type_id() == "GammaCompressionEffect") {
1061                                 assert(node->incoming_links.size() == 1);
1062                                 assert(node->incoming_links[0]->output_alpha_type == ALPHA_PREMULTIPLIED);
1063                                 desired_type = ALPHA_POSTMULTIPLIED;
1064                         }
1065
1066                         // Go through each input that is not premultiplied alpha, and insert
1067                         // a conversion before it.
1068                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
1069                                 Node *input = node->incoming_links[j];
1070                                 assert(input->output_alpha_type != ALPHA_INVALID);
1071                                 if (input->output_alpha_type == desired_type ||
1072                                     input->output_alpha_type == ALPHA_BLANK) {
1073                                         continue;
1074                                 }
1075                                 Node *conversion;
1076                                 if (desired_type == ALPHA_PREMULTIPLIED) {
1077                                         conversion = add_node(new AlphaMultiplicationEffect());
1078                                 } else {
1079                                         conversion = add_node(new AlphaDivisionEffect());
1080                                 }
1081                                 conversion->output_alpha_type = desired_type;
1082                                 replace_sender(input, conversion);
1083                                 connect_nodes(input, conversion);
1084                         }
1085
1086                         // Re-sort topologically, and propagate the new information.
1087                         propagate_gamma_and_color_space();
1088                         propagate_alpha();
1089
1090                         found_any = true;
1091                         break;
1092                 }
1093
1094                 char filename[256];
1095                 sprintf(filename, "step%u-alphafix-iter%u.dot", step, ++alpha_propagation_pass);
1096                 output_dot(filename);
1097                 assert(alpha_propagation_pass < 100);
1098         } while (found_any);
1099
1100         for (unsigned i = 0; i < nodes.size(); ++i) {
1101                 Node *node = nodes[i];
1102                 if (node->disabled) {
1103                         continue;
1104                 }
1105                 assert(node->output_alpha_type != ALPHA_INVALID);
1106         }
1107 }
1108
1109 // Make so that the output is in the desired color space.
1110 void EffectChain::fix_output_color_space()
1111 {
1112         Node *output = find_output_node();
1113         if (output->output_color_space != output_format.color_space) {
1114                 Node *conversion = add_node(new ColorspaceConversionEffect());
1115                 CHECK(conversion->effect->set_int("source_space", output->output_color_space));
1116                 CHECK(conversion->effect->set_int("destination_space", output_format.color_space));
1117                 conversion->output_color_space = output_format.color_space;
1118                 connect_nodes(output, conversion);
1119                 propagate_alpha();
1120                 propagate_gamma_and_color_space();
1121         }
1122 }
1123
1124 // Make so that the output is in the desired pre-/postmultiplication alpha state.
1125 void EffectChain::fix_output_alpha()
1126 {
1127         Node *output = find_output_node();
1128         assert(output->output_alpha_type != ALPHA_INVALID);
1129         if (output->output_alpha_type == ALPHA_BLANK) {
1130                 // No alpha output, so we don't care.
1131                 return;
1132         }
1133         if (output->output_alpha_type == ALPHA_PREMULTIPLIED &&
1134             output_alpha_format == OUTPUT_ALPHA_FORMAT_POSTMULTIPLIED) {
1135                 Node *conversion = add_node(new AlphaDivisionEffect());
1136                 connect_nodes(output, conversion);
1137                 propagate_alpha();
1138                 propagate_gamma_and_color_space();
1139         }
1140         if (output->output_alpha_type == ALPHA_POSTMULTIPLIED &&
1141             output_alpha_format == OUTPUT_ALPHA_FORMAT_PREMULTIPLIED) {
1142                 Node *conversion = add_node(new AlphaMultiplicationEffect());
1143                 connect_nodes(output, conversion);
1144                 propagate_alpha();
1145                 propagate_gamma_and_color_space();
1146         }
1147 }
1148
1149 bool EffectChain::node_needs_gamma_fix(Node *node)
1150 {
1151         if (node->disabled) {
1152                 return false;
1153         }
1154
1155         // Small hack since the output is not an explicit node:
1156         // If we are the last node and our output is in the wrong
1157         // space compared to EffectChain's output, we need to fix it.
1158         // This will only take us to linear, but fix_output_gamma()
1159         // will come and take us to the desired output gamma
1160         // if it is needed.
1161         //
1162         // This needs to be before everything else, since it could
1163         // even apply to inputs (if they are the only effect).
1164         if (node->outgoing_links.empty() &&
1165             node->output_gamma_curve != output_format.gamma_curve &&
1166             node->output_gamma_curve != GAMMA_LINEAR) {
1167                 return true;
1168         }
1169
1170         if (node->effect->num_inputs() == 0) {
1171                 return false;
1172         }
1173
1174         // propagate_gamma_and_color_space() has already set our output
1175         // to GAMMA_INVALID if the inputs differ, so we can rely on that,
1176         // except for GammaCompressionEffect.
1177         if (node->output_gamma_curve == GAMMA_INVALID) {
1178                 return true;
1179         }
1180         if (node->effect->effect_type_id() == "GammaCompressionEffect") {
1181                 assert(node->incoming_links.size() == 1);
1182                 return node->incoming_links[0]->output_gamma_curve != GAMMA_LINEAR;
1183         }
1184
1185         return (node->effect->needs_linear_light() && node->output_gamma_curve != GAMMA_LINEAR);
1186 }
1187
1188 // Very similar to fix_internal_color_spaces(), but for gamma.
1189 // There is one difference, though; before we start adding conversion nodes,
1190 // we see if we can get anything out of asking the sources to deliver
1191 // linear gamma directly. fix_internal_gamma_by_asking_inputs()
1192 // does that part, while fix_internal_gamma_by_inserting_nodes()
1193 // inserts nodes as needed afterwards.
1194 void EffectChain::fix_internal_gamma_by_asking_inputs(unsigned step)
1195 {
1196         unsigned gamma_propagation_pass = 0;
1197         bool found_any;
1198         do {
1199                 found_any = false;
1200                 for (unsigned i = 0; i < nodes.size(); ++i) {
1201                         Node *node = nodes[i];
1202                         if (!node_needs_gamma_fix(node)) {
1203                                 continue;
1204                         }
1205
1206                         // See if all inputs can give us linear gamma. If not, leave it.
1207                         std::vector<Node *> nonlinear_inputs;
1208                         find_all_nonlinear_inputs(node, &nonlinear_inputs);
1209                         assert(!nonlinear_inputs.empty());
1210
1211                         bool all_ok = true;
1212                         for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
1213                                 Input *input = static_cast<Input *>(nonlinear_inputs[i]->effect);
1214                                 all_ok &= input->can_output_linear_gamma();
1215                         }
1216
1217                         if (!all_ok) {
1218                                 continue;
1219                         }
1220
1221                         for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
1222                                 CHECK(nonlinear_inputs[i]->effect->set_int("output_linear_gamma", 1));
1223                                 nonlinear_inputs[i]->output_gamma_curve = GAMMA_LINEAR;
1224                         }
1225
1226                         // Re-sort topologically, and propagate the new information.
1227                         propagate_gamma_and_color_space();
1228
1229                         found_any = true;
1230                         break;
1231                 }
1232
1233                 char filename[256];
1234                 sprintf(filename, "step%u-gammafix-iter%u.dot", step, ++gamma_propagation_pass);
1235                 output_dot(filename);
1236                 assert(gamma_propagation_pass < 100);
1237         } while (found_any);
1238 }
1239
1240 void EffectChain::fix_internal_gamma_by_inserting_nodes(unsigned step)
1241 {
1242         unsigned gamma_propagation_pass = 0;
1243         bool found_any;
1244         do {
1245                 found_any = false;
1246                 for (unsigned i = 0; i < nodes.size(); ++i) {
1247                         Node *node = nodes[i];
1248                         if (!node_needs_gamma_fix(node)) {
1249                                 continue;
1250                         }
1251
1252                         // Special case: We could be an input and still be asked to
1253                         // fix our gamma; if so, we should be the only node
1254                         // (as node_needs_gamma_fix() would only return true in
1255                         // for an input in that case). That means we should insert
1256                         // a conversion node _after_ ourselves.
1257                         if (node->incoming_links.empty()) {
1258                                 assert(node->outgoing_links.empty());
1259                                 Node *conversion = add_node(new GammaExpansionEffect());
1260                                 CHECK(conversion->effect->set_int("source_curve", node->output_gamma_curve));
1261                                 conversion->output_gamma_curve = GAMMA_LINEAR;
1262                                 connect_nodes(node, conversion);
1263                         }
1264
1265                         // If not, go through each input that is not linear gamma,
1266                         // and insert a gamma conversion after it.
1267                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
1268                                 Node *input = node->incoming_links[j];
1269                                 assert(input->output_gamma_curve != GAMMA_INVALID);
1270                                 if (input->output_gamma_curve == GAMMA_LINEAR) {
1271                                         continue;
1272                                 }
1273                                 Node *conversion = add_node(new GammaExpansionEffect());
1274                                 CHECK(conversion->effect->set_int("source_curve", input->output_gamma_curve));
1275                                 conversion->output_gamma_curve = GAMMA_LINEAR;
1276                                 replace_sender(input, conversion);
1277                                 connect_nodes(input, conversion);
1278                         }
1279
1280                         // Re-sort topologically, and propagate the new information.
1281                         propagate_alpha();
1282                         propagate_gamma_and_color_space();
1283
1284                         found_any = true;
1285                         break;
1286                 }
1287
1288                 char filename[256];
1289                 sprintf(filename, "step%u-gammafix-iter%u.dot", step, ++gamma_propagation_pass);
1290                 output_dot(filename);
1291                 assert(gamma_propagation_pass < 100);
1292         } while (found_any);
1293
1294         for (unsigned i = 0; i < nodes.size(); ++i) {
1295                 Node *node = nodes[i];
1296                 if (node->disabled) {
1297                         continue;
1298                 }
1299                 assert(node->output_gamma_curve != GAMMA_INVALID);
1300         }
1301 }
1302
1303 // Make so that the output is in the desired gamma.
1304 // Note that this assumes linear input gamma, so it might create the need
1305 // for another pass of fix_internal_gamma().
1306 void EffectChain::fix_output_gamma()
1307 {
1308         Node *output = find_output_node();
1309         if (output->output_gamma_curve != output_format.gamma_curve) {
1310                 Node *conversion = add_node(new GammaCompressionEffect());
1311                 CHECK(conversion->effect->set_int("destination_curve", output_format.gamma_curve));
1312                 conversion->output_gamma_curve = output_format.gamma_curve;
1313                 connect_nodes(output, conversion);
1314         }
1315 }
1316
1317 // If the user has requested dither, add a DitherEffect right at the end
1318 // (after GammaCompressionEffect etc.). This needs to be done after everything else,
1319 // since dither is about the only effect that can _not_ be done in linear space.
1320 void EffectChain::add_dither_if_needed()
1321 {
1322         if (num_dither_bits == 0) {
1323                 return;
1324         }
1325         Node *output = find_output_node();
1326         Node *dither = add_node(new DitherEffect());
1327         CHECK(dither->effect->set_int("num_bits", num_dither_bits));
1328         connect_nodes(output, dither);
1329
1330         dither_effect = dither->effect;
1331 }
1332
1333 // Find the output node. This is, simply, one that has no outgoing links.
1334 // If there are multiple ones, the graph is malformed (we do not support
1335 // multiple outputs right now).
1336 Node *EffectChain::find_output_node()
1337 {
1338         std::vector<Node *> output_nodes;
1339         for (unsigned i = 0; i < nodes.size(); ++i) {
1340                 Node *node = nodes[i];
1341                 if (node->disabled) {
1342                         continue;
1343                 }
1344                 if (node->outgoing_links.empty()) {
1345                         output_nodes.push_back(node);
1346                 }
1347         }
1348         assert(output_nodes.size() == 1);
1349         return output_nodes[0];
1350 }
1351
1352 void EffectChain::finalize()
1353 {
1354         // Save the current locale, and set it to C, so that we can output decimal
1355         // numbers with printf and be sure to get them in the format mandated by GLSL.
1356         char *saved_locale = setlocale(LC_NUMERIC, "C");
1357
1358         // Output the graph as it is before we do any conversions on it.
1359         output_dot("step0-start.dot");
1360
1361         // Give each effect in turn a chance to rewrite its own part of the graph.
1362         // Note that if more effects are added as part of this, they will be
1363         // picked up as part of the same for loop, since they are added at the end.
1364         for (unsigned i = 0; i < nodes.size(); ++i) {
1365                 nodes[i]->effect->rewrite_graph(this, nodes[i]);
1366         }
1367         output_dot("step1-rewritten.dot");
1368
1369         find_color_spaces_for_inputs();
1370         output_dot("step2-input-colorspace.dot");
1371
1372         propagate_alpha();
1373         output_dot("step3-propagated-alpha.dot");
1374
1375         propagate_gamma_and_color_space();
1376         output_dot("step4-propagated-all.dot");
1377
1378         fix_internal_color_spaces();
1379         fix_internal_alpha(6);
1380         fix_output_color_space();
1381         output_dot("step7-output-colorspacefix.dot");
1382         fix_output_alpha();
1383         output_dot("step8-output-alphafix.dot");
1384
1385         // Note that we need to fix gamma after colorspace conversion,
1386         // because colorspace conversions might create needs for gamma conversions.
1387         // Also, we need to run an extra pass of fix_internal_gamma() after
1388         // fixing the output gamma, as we only have conversions to/from linear,
1389         // and fix_internal_alpha() since GammaCompressionEffect needs
1390         // postmultiplied input.
1391         fix_internal_gamma_by_asking_inputs(9);
1392         fix_internal_gamma_by_inserting_nodes(10);
1393         fix_output_gamma();
1394         output_dot("step11-output-gammafix.dot");
1395         propagate_alpha();
1396         output_dot("step12-output-alpha-propagated.dot");
1397         fix_internal_alpha(13);
1398         output_dot("step14-output-alpha-fixed.dot");
1399         fix_internal_gamma_by_asking_inputs(15);
1400         fix_internal_gamma_by_inserting_nodes(16);
1401
1402         output_dot("step17-before-dither.dot");
1403
1404         add_dither_if_needed();
1405
1406         output_dot("step18-final.dot");
1407
1408         // Construct all needed GLSL programs, starting at the output.
1409         construct_glsl_programs(find_output_node());
1410
1411         output_dot("step19-split-to-phases.dot");
1412
1413         for (unsigned i = 0; i < inputs.size(); ++i) {
1414                 inputs[i]->finalize();
1415         }
1416
1417         assert(phases[0]->inputs.empty());
1418
1419         finalized = true;
1420         setlocale(LC_NUMERIC, saved_locale);
1421 }
1422
1423 void EffectChain::render_to_fbo(GLuint dest_fbo, unsigned width, unsigned height)
1424 {
1425         assert(finalized);
1426
1427         // Save original viewport.
1428         GLuint x = 0, y = 0;
1429         GLuint fbo = 0;
1430
1431         if (width == 0 && height == 0) {
1432                 GLint viewport[4];
1433                 glGetIntegerv(GL_VIEWPORT, viewport);
1434                 x = viewport[0];
1435                 y = viewport[1];
1436                 width = viewport[2];
1437                 height = viewport[3];
1438         }
1439
1440         // Basic state.
1441         glDisable(GL_BLEND);
1442         check_error();
1443         glDisable(GL_DEPTH_TEST);
1444         check_error();
1445         glDepthMask(GL_FALSE);
1446         check_error();
1447
1448         glMatrixMode(GL_PROJECTION);
1449         glLoadIdentity();
1450         glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
1451
1452         glMatrixMode(GL_MODELVIEW);
1453         glLoadIdentity();
1454
1455         if (phases.size() > 1) {
1456                 glGenFramebuffers(1, &fbo);
1457                 check_error();
1458                 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
1459                 check_error();
1460         }
1461
1462         std::set<Node *> generated_mipmaps;
1463
1464         // We choose the simplest option of having one texture per output,
1465         // since otherwise this turns into an (albeit simple) register allocation problem.
1466         std::map<Phase *, GLuint> output_textures;
1467
1468         for (unsigned phase = 0; phase < phases.size(); ++phase) {
1469                 // Find a texture for this phase.
1470                 inform_input_sizes(phases[phase]);
1471                 if (phase != phases.size() - 1) {
1472                         find_output_size(phases[phase]);
1473
1474                         GLuint tex_num = resource_pool->create_2d_texture(GL_RGBA16F_ARB, phases[phase]->output_width, phases[phase]->output_height);
1475                         output_textures.insert(std::make_pair(phases[phase], tex_num));
1476                 }
1477
1478                 glUseProgram(phases[phase]->glsl_program_num);
1479                 check_error();
1480
1481                 // Set up RTT inputs for this phase.
1482                 for (unsigned sampler = 0; sampler < phases[phase]->inputs.size(); ++sampler) {
1483                         glActiveTexture(GL_TEXTURE0 + sampler);
1484                         Node *input = phases[phase]->inputs[sampler];
1485                         glBindTexture(GL_TEXTURE_2D, output_textures[input->phase]);
1486                         check_error();
1487                         if (phases[phase]->input_needs_mipmaps) {
1488                                 if (generated_mipmaps.count(input) == 0) {
1489                                         glGenerateMipmap(GL_TEXTURE_2D);
1490                                         check_error();
1491                                         generated_mipmaps.insert(input);
1492                                 }
1493                                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
1494                                 check_error();
1495                         } else {
1496                                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
1497                                 check_error();
1498                         }
1499                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
1500                         check_error();
1501                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
1502                         check_error();
1503
1504                         std::string texture_name = std::string("tex_") + phases[phase]->effect_ids[input];
1505                         glUniform1i(glGetUniformLocation(phases[phase]->glsl_program_num, texture_name.c_str()), sampler);
1506                         check_error();
1507                 }
1508
1509                 // And now the output.
1510                 if (phase == phases.size() - 1) {
1511                         // Last phase goes to the output the user specified.
1512                         glBindFramebuffer(GL_FRAMEBUFFER, dest_fbo);
1513                         check_error();
1514                         GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
1515                         assert(status == GL_FRAMEBUFFER_COMPLETE);
1516                         glViewport(x, y, width, height);
1517                         if (dither_effect != NULL) {
1518                                 CHECK(dither_effect->set_int("output_width", width));
1519                                 CHECK(dither_effect->set_int("output_height", height));
1520                         }
1521                 } else {
1522                         glFramebufferTexture2D(
1523                                 GL_FRAMEBUFFER,
1524                                 GL_COLOR_ATTACHMENT0,
1525                                 GL_TEXTURE_2D,
1526                                 output_textures[phases[phase]],
1527                                 0);
1528                         check_error();
1529                         GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
1530                         assert(status == GL_FRAMEBUFFER_COMPLETE);
1531                         glViewport(0, 0, phases[phase]->output_width, phases[phase]->output_height);
1532                 }
1533
1534                 // Give the required parameters to all the effects.
1535                 unsigned sampler_num = phases[phase]->inputs.size();
1536                 for (unsigned i = 0; i < phases[phase]->effects.size(); ++i) {
1537                         Node *node = phases[phase]->effects[i];
1538                         node->effect->set_gl_state(phases[phase]->glsl_program_num, phases[phase]->effect_ids[node], &sampler_num);
1539                         check_error();
1540                 }
1541
1542                 // Now draw!
1543                 glBegin(GL_QUADS);
1544
1545                 glTexCoord2f(0.0f, 0.0f);
1546                 glVertex2f(0.0f, 0.0f);
1547
1548                 glTexCoord2f(1.0f, 0.0f);
1549                 glVertex2f(1.0f, 0.0f);
1550
1551                 glTexCoord2f(1.0f, 1.0f);
1552                 glVertex2f(1.0f, 1.0f);
1553
1554                 glTexCoord2f(0.0f, 1.0f);
1555                 glVertex2f(0.0f, 1.0f);
1556
1557                 glEnd();
1558                 check_error();
1559
1560                 for (unsigned i = 0; i < phases[phase]->effects.size(); ++i) {
1561                         Node *node = phases[phase]->effects[i];
1562                         node->effect->clear_gl_state();
1563                 }
1564         }
1565
1566         for (std::map<Phase *, GLuint>::const_iterator texture_it = output_textures.begin();
1567              texture_it != output_textures.end();
1568              ++texture_it) {
1569                 resource_pool->release_2d_texture(texture_it->second);
1570         }
1571
1572         glBindFramebuffer(GL_FRAMEBUFFER, 0);
1573         check_error();
1574
1575         if (fbo != 0) {
1576                 glDeleteFramebuffers(1, &fbo);
1577                 check_error();
1578         }
1579 }