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

   1 #define GL_GLEXT_PROTOTYPES 1
   2
   3 #include <stdio.h>
   4 #include <math.h>
   5 #include <string.h>
   6 #include <assert.h>
   7
   8 #include <algorithm>
   9 #include <set>
  10 #include <stack>
  11 #include <vector>
  12
  13 #include "util.h"
  14 #include "effect_chain.h"
  15 #include "gamma_expansion_effect.h"
  16 #include "gamma_compression_effect.h"
  17 #include "colorspace_conversion_effect.h"
  18 #include "input.h"
  19 #include "opengl.h"
  20
  21 EffectChain::EffectChain(float aspect_nom, float aspect_denom)
  22         : aspect_nom(aspect_nom),
  23           aspect_denom(aspect_denom),
  24           finalized(false) {}
  25
  26 Input *EffectChain::add_input(Input *input)
  27 {
  28         inputs.push_back(input);
  29
  30         Node *node = add_node(input);
  31         node->output_color_space = input->get_color_space();
  32         node->output_gamma_curve = input->get_gamma_curve();
  33         return input;
  34 }
  35
  36 void EffectChain::add_output(const ImageFormat &format)
  37 {
  38         output_format = format;
  39 }
  40
  41 Node *EffectChain::add_node(Effect *effect)
  42 {
  43         char effect_id[256];
  44         sprintf(effect_id, "eff%u", (unsigned)nodes.size());
  45
  46         Node *node = new Node;
  47         node->effect = effect;
  48         node->disabled = false;
  49         node->effect_id = effect_id;
  50         node->output_color_space = COLORSPACE_INVALID;
  51         node->output_gamma_curve = GAMMA_INVALID;
  52
  53         nodes.push_back(node);
  54         node_map[effect] = node;
  55         return node;
  56 }
  57
  58 void EffectChain::connect_nodes(Node *sender, Node *receiver)
  59 {
  60         sender->outgoing_links.push_back(receiver);
  61         receiver->incoming_links.push_back(sender);
  62 }
  63
  64 void EffectChain::replace_receiver(Node *old_receiver, Node *new_receiver)
  65 {
  66         new_receiver->incoming_links = old_receiver->incoming_links;
  67         old_receiver->incoming_links.clear();
  68
  69         for (unsigned i = 0; i < new_receiver->incoming_links.size(); ++i) {
  70                 Node *sender = new_receiver->incoming_links[i];
  71                 for (unsigned j = 0; j < sender->outgoing_links.size(); ++j) {
  72                         if (sender->outgoing_links[j] == old_receiver) {
  73                                 sender->outgoing_links[j] = new_receiver;
  74                         }
  75                 }
  76         }
  77 }
  78
  79 void EffectChain::replace_sender(Node *old_sender, Node *new_sender)
  80 {
  81         new_sender->outgoing_links = old_sender->outgoing_links;
  82         old_sender->outgoing_links.clear();
  83
  84         for (unsigned i = 0; i < new_sender->outgoing_links.size(); ++i) {
  85                 Node *receiver = new_sender->outgoing_links[i];
  86                 for (unsigned j = 0; j < receiver->incoming_links.size(); ++j) {
  87                         if (receiver->incoming_links[j] == old_sender) {
  88                                 receiver->incoming_links[j] = new_sender;
  89                         }
  90                 }
  91         }
  92 }
  93
  94 void EffectChain::insert_node_between(Node *sender, Node *middle, Node *receiver)
  95 {
  96         for (unsigned i = 0; i < sender->outgoing_links.size(); ++i) {
  97                 if (sender->outgoing_links[i] == receiver) {
  98                         sender->outgoing_links[i] = middle;
  99                         middle->incoming_links.push_back(sender);
 100                 }
 101         }
 102         for (unsigned i = 0; i < receiver->incoming_links.size(); ++i) {
 103                 if (receiver->incoming_links[i] == sender) {
 104                         receiver->incoming_links[i] = middle;
 105                         middle->outgoing_links.push_back(receiver);
 106                 }
 107         }
 108
 109         assert(middle->incoming_links.size() == middle->effect->num_inputs());
 110 }
 111
 112 void EffectChain::find_all_nonlinear_inputs(Node *node, std::vector<Node *> *nonlinear_inputs)
 113 {
 114         if (node->output_gamma_curve == GAMMA_LINEAR &&
 115             node->effect->effect_type_id() != "GammaCompressionEffect") {
 116                 return;
 117         }
 118         if (node->effect->num_inputs() == 0) {
 119                 nonlinear_inputs->push_back(node);
 120         } else {
 121                 assert(node->effect->num_inputs() == node->incoming_links.size());
 122                 for (unsigned i = 0; i < node->incoming_links.size(); ++i) {
 123                         find_all_nonlinear_inputs(node->incoming_links[i], nonlinear_inputs);
 124                 }
 125         }
 126 }
 127
 128 Effect *EffectChain::add_effect(Effect *effect, const std::vector<Effect *> &inputs)
 129 {
 130         assert(inputs.size() == effect->num_inputs());
 131         Node *node = add_node(effect);
 132         for (unsigned i = 0; i < inputs.size(); ++i) {
 133                 assert(node_map.count(inputs[i]) != 0);
 134                 connect_nodes(node_map[inputs[i]], node);
 135         }
 136         return effect;
 137 }
 138
 139 // GLSL pre-1.30 doesn't support token pasting. Replace PREFIX(x) with <effect_id>_x.
 140 std::string replace_prefix(const std::string &text, const std::string &prefix)
 141 {
 142         std::string output;
 143         size_t start = 0;
 144
 145         while (start < text.size()) {
 146                 size_t pos = text.find("PREFIX(", start);
 147                 if (pos == std::string::npos) {
 148                         output.append(text.substr(start, std::string::npos));
 149                         break;
 150                 }
 151
 152                 output.append(text.substr(start, pos - start));
 153                 output.append(prefix);
 154                 output.append("_");
 155
 156                 pos += strlen("PREFIX(");
 157
 158                 // Output stuff until we find the matching ), which we then eat.
 159                 int depth = 1;
 160                 size_t end_arg_pos = pos;
 161                 while (end_arg_pos < text.size()) {
 162                         if (text[end_arg_pos] == '(') {
 163                                 ++depth;
 164                         } else if (text[end_arg_pos] == ')') {
 165                                 --depth;
 166                                 if (depth == 0) {
 167                                         break;
 168                                 }
 169                         }
 170                         ++end_arg_pos;
 171                 }
 172                 output.append(text.substr(pos, end_arg_pos - pos));
 173                 ++end_arg_pos;
 174                 assert(depth == 0);
 175                 start = end_arg_pos;
 176         }
 177         return output;
 178 }
 179
 180 Phase *EffectChain::compile_glsl_program(
 181         const std::vector<Node *> &inputs,
 182         const std::vector<Node *> &effects)
 183 {
 184         assert(!effects.empty());
 185
 186         // Deduplicate the inputs.
 187         std::vector<Node *> true_inputs = inputs;
 188         std::sort(true_inputs.begin(), true_inputs.end());
 189         true_inputs.erase(std::unique(true_inputs.begin(), true_inputs.end()), true_inputs.end());
 190
 191         bool input_needs_mipmaps = false;
 192         std::string frag_shader = read_file("header.frag");
 193
 194         // Create functions for all the texture inputs that we need.
 195         for (unsigned i = 0; i < true_inputs.size(); ++i) {
 196                 Node *input = true_inputs[i];
 197
 198                 frag_shader += std::string("uniform sampler2D tex_") + input->effect_id + ";\n";
 199                 frag_shader += std::string("vec4 ") + input->effect_id + "(vec2 tc) {\n";
 200                 frag_shader += "\treturn texture2D(tex_" + input->effect_id + ", tc);\n";
 201                 frag_shader += "}\n";
 202                 frag_shader += "\n";
 203         }
 204
 205         for (unsigned i = 0; i < effects.size(); ++i) {
 206                 Node *node = effects[i];
 207
 208                 if (node->incoming_links.size() == 1) {
 209                         frag_shader += std::string("#define INPUT ") + node->incoming_links[0]->effect_id + "\n";
 210                 } else {
 211                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 212                                 char buf[256];
 213                                 sprintf(buf, "#define INPUT%d %s\n", j + 1, node->incoming_links[j]->effect_id.c_str());
 214                                 frag_shader += buf;
 215                         }
 216                 }
 217
 218                 frag_shader += "\n";
 219                 frag_shader += std::string("#define FUNCNAME ") + node->effect_id + "\n";
 220                 frag_shader += replace_prefix(node->effect->output_convenience_uniforms(), node->effect_id);
 221                 frag_shader += replace_prefix(node->effect->output_fragment_shader(), node->effect_id);
 222                 frag_shader += "#undef PREFIX\n";
 223                 frag_shader += "#undef FUNCNAME\n";
 224                 if (node->incoming_links.size() == 1) {
 225                         frag_shader += "#undef INPUT\n";
 226                 } else {
 227                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 228                                 char buf[256];
 229                                 sprintf(buf, "#undef INPUT%d\n", j + 1);
 230                                 frag_shader += buf;
 231                         }
 232                 }
 233                 frag_shader += "\n";
 234
 235                 input_needs_mipmaps |= node->effect->needs_mipmaps();
 236         }
 237         for (unsigned i = 0; i < effects.size(); ++i) {
 238                 Node *node = effects[i];
 239                 if (node->effect->num_inputs() == 0) {
 240                         node->effect->set_int("needs_mipmaps", input_needs_mipmaps);
 241                 }
 242         }
 243         frag_shader += std::string("#define INPUT ") + effects.back()->effect_id + "\n";
 244         frag_shader.append(read_file("footer.frag"));
 245
 246         // Output shader to a temporary file, for easier debugging.
 247         static int compiled_shader_num = 0;
 248         char filename[256];
 249         sprintf(filename, "chain-%03d.frag", compiled_shader_num++);
 250         FILE *fp = fopen(filename, "w");
 251         if (fp == NULL) {
 252                 perror(filename);
 253                 exit(1);
 254         }
 255         fprintf(fp, "%s\n", frag_shader.c_str());
 256         fclose(fp);
 257
 258         GLuint glsl_program_num = glCreateProgram();
 259         GLuint vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 260         GLuint fs_obj = compile_shader(frag_shader, GL_FRAGMENT_SHADER);
 261         glAttachShader(glsl_program_num, vs_obj);
 262         check_error();
 263         glAttachShader(glsl_program_num, fs_obj);
 264         check_error();
 265         glLinkProgram(glsl_program_num);
 266         check_error();
 267
 268         Phase *phase = new Phase;
 269         phase->glsl_program_num = glsl_program_num;
 270         phase->input_needs_mipmaps = input_needs_mipmaps;
 271         phase->inputs = true_inputs;
 272         phase->effects = effects;
 273
 274         return phase;
 275 }
 276
 277 // Construct GLSL programs, starting at the given effect and following
 278 // the chain from there. We end a program every time we come to an effect
 279 // marked as "needs texture bounce", one that is used by multiple other
 280 // effects, every time an effect wants to change the output size,
 281 // and of course at the end.
 282 //
 283 // We follow a quite simple depth-first search from the output, although
 284 // without any explicit recursion.
 285 void EffectChain::construct_glsl_programs(Node *output)
 286 {
 287         // Which effects have already been completed in this phase?
 288         // We need to keep track of it, as an effect with multiple outputs
 289         // could otherwise be calculate multiple times.
 290         std::set<Node *> completed_effects;
 291
 292         // Effects in the current phase, as well as inputs (outputs from other phases
 293         // that we depend on). Note that since we start iterating from the end,
 294         // the effect list will be in the reverse order.
 295         std::vector<Node *> this_phase_inputs;
 296         std::vector<Node *> this_phase_effects;
 297
 298         // Effects that we have yet to calculate, but that we know should
 299         // be in the current phase.
 300         std::stack<Node *> effects_todo_this_phase;
 301
 302         // Effects that we have yet to calculate, but that come from other phases.
 303         // We delay these until we have this phase done in its entirety,
 304         // at which point we pick any of them and start a new phase from that.
 305         std::stack<Node *> effects_todo_other_phases;
 306
 307         effects_todo_this_phase.push(output);
 308
 309         for ( ;; ) {  // Termination condition within loop.
 310                 if (!effects_todo_this_phase.empty()) {
 311                         // OK, we have more to do this phase.
 312                         Node *node = effects_todo_this_phase.top();
 313                         effects_todo_this_phase.pop();
 314
 315                         // This should currently only happen for effects that are phase outputs,
 316                         // and we throw those out separately below.
 317                         assert(completed_effects.count(node) == 0);
 318
 319                         this_phase_effects.push_back(node);
 320                         completed_effects.insert(node);
 321
 322                         // Find all the dependencies of this effect, and add them to the stack.
 323                         std::vector<Node *> deps = node->incoming_links;
 324                         assert(node->effect->num_inputs() == deps.size());
 325                         for (unsigned i = 0; i < deps.size(); ++i) {
 326                                 bool start_new_phase = false;
 327
 328                                 // FIXME: If we sample directly from a texture, we won't need this.
 329                                 if (node->effect->needs_texture_bounce()) {
 330                                         start_new_phase = true;
 331                                 }
 332
 333                                 if (deps[i]->outgoing_links.size() > 1) {
 334                                         if (deps[i]->effect->num_inputs() > 0) {
 335                                                 // More than one effect uses this as the input,
 336                                                 // and it is not a texture itself.
 337                                                 // The easiest thing to do (and probably also the safest
 338                                                 // performance-wise in most cases) is to bounce it to a texture
 339                                                 // and then let the next passes read from that.
 340                                                 start_new_phase = true;
 341                                         } else {
 342                                                 // For textures, we try to be slightly more clever;
 343                                                 // if none of our outputs need a bounce, we don't bounce
 344                                                 // but instead simply use the effect many times.
 345                                                 //
 346                                                 // Strictly speaking, we could bounce it for some outputs
 347                                                 // and use it directly for others, but the processing becomes
 348                                                 // somewhat simpler if the effect is only used in one such way.
 349                                                 for (unsigned j = 0; j < deps[i]->outgoing_links.size(); ++j) {
 350                                                         Node *rdep = deps[i]->outgoing_links[j];
 351                                                         start_new_phase |= rdep->effect->needs_texture_bounce();
 352                                                 }
 353                                         }
 354                                 }
 355
 356                                 if (deps[i]->effect->changes_output_size()) {
 357                                         start_new_phase = true;
 358                                 }
 359
 360                                 if (start_new_phase) {
 361                                         effects_todo_other_phases.push(deps[i]);
 362                                         this_phase_inputs.push_back(deps[i]);
 363                                 } else {
 364                                         effects_todo_this_phase.push(deps[i]);
 365                                 }
 366                         }
 367                         continue;
 368                 }
 369
 370                 // No more effects to do this phase. Take all the ones we have,
 371                 // and create a GLSL program for it.
 372                 if (!this_phase_effects.empty()) {
 373                         reverse(this_phase_effects.begin(), this_phase_effects.end());
 374                         phases.push_back(compile_glsl_program(this_phase_inputs, this_phase_effects));
 375                         this_phase_effects.back()->phase = phases.back();
 376                         this_phase_inputs.clear();
 377                         this_phase_effects.clear();
 378                 }
 379                 assert(this_phase_inputs.empty());
 380                 assert(this_phase_effects.empty());
 381
 382                 // If we have no effects left, exit.
 383                 if (effects_todo_other_phases.empty()) {
 384                         break;
 385                 }
 386
 387                 Node *node = effects_todo_other_phases.top();
 388                 effects_todo_other_phases.pop();
 389
 390                 if (completed_effects.count(node) == 0) {
 391                         // Start a new phase, calculating from this effect.
 392                         effects_todo_this_phase.push(node);
 393                 }
 394         }
 395
 396         // Finally, since the phases are found from the output but must be executed
 397         // from the input(s), reverse them, too.
 398         std::reverse(phases.begin(), phases.end());
 399 }
 400
 401 void EffectChain::output_dot(const char *filename)
 402 {
 403         FILE *fp = fopen(filename, "w");
 404         if (fp == NULL) {
 405                 perror(filename);
 406                 exit(1);
 407         }
 408
 409         fprintf(fp, "digraph G {\n");
 410         for (unsigned i = 0; i < nodes.size(); ++i) {
 411                 // Find out which phase this event belongs to.
 412                 int in_phase = -1;
 413                 for (unsigned j = 0; j < phases.size(); ++j) {
 414                         const Phase* p = phases[j];
 415                         if (std::find(p->effects.begin(), p->effects.end(), nodes[i]) != p->effects.end()) {
 416                                 assert(in_phase == -1);
 417                                 in_phase = j;
 418                         }
 419                 }
 420
 421                 if (in_phase == -1) {
 422                         fprintf(fp, "  n%ld [label=\"%s\"];\n", (long)nodes[i], nodes[i]->effect->effect_type_id().c_str());
 423                 } else {
 424                         fprintf(fp, "  n%ld [label=\"%s\" style=\"filled\" fillcolor=\"/accent8/%d\"];\n",
 425                                 (long)nodes[i], nodes[i]->effect->effect_type_id().c_str(),
 426                                 (in_phase % 8) + 1);
 427                 }
 428                 for (unsigned j = 0; j < nodes[i]->outgoing_links.size(); ++j) {
 429                         std::vector<std::string> labels;
 430
 431                         if (nodes[i]->outgoing_links[j]->effect->needs_texture_bounce()) {
 432                                 labels.push_back("needs_bounce");
 433                         }
 434                         if (nodes[i]->effect->changes_output_size()) {
 435                                 labels.push_back("resize");
 436                         }
 437
 438                         switch (nodes[i]->output_color_space) {
 439                         case COLORSPACE_INVALID:
 440                                 labels.push_back("spc[invalid]");
 441                                 break;
 442                         case COLORSPACE_REC_601_525:
 443                                 labels.push_back("spc[rec601-525]");
 444                                 break;
 445                         case COLORSPACE_REC_601_625:
 446                                 labels.push_back("spc[rec601-625]");
 447                                 break;
 448                         default:
 449                                 break;
 450                         }
 451
 452                         switch (nodes[i]->output_gamma_curve) {
 453                         case GAMMA_INVALID:
 454                                 labels.push_back("gamma[invalid]");
 455                                 break;
 456                         case GAMMA_sRGB:
 457                                 labels.push_back("gamma[sRGB]");
 458                                 break;
 459                         case GAMMA_REC_601:  // and GAMMA_REC_709
 460                                 labels.push_back("gamma[rec601/709]");
 461                                 break;
 462                         default:
 463                                 break;
 464                         }
 465
 466                         if (labels.empty()) {
 467                                 fprintf(fp, "  n%ld -> n%ld;\n", (long)nodes[i], (long)nodes[i]->outgoing_links[j]);
 468                         } else {
 469                                 std::string label = labels[0];
 470                                 for (unsigned k = 1; k < labels.size(); ++k) {
 471                                         label += ", " + labels[k];
 472                                 }
 473                                 fprintf(fp, "  n%ld -> n%ld [label=\"%s\"];\n", (long)nodes[i], (long)nodes[i]->outgoing_links[j], label.c_str());
 474                         }
 475                 }
 476         }
 477         fprintf(fp, "}\n");
 478
 479         fclose(fp);
 480 }
 481
 482 unsigned EffectChain::fit_rectangle_to_aspect(unsigned width, unsigned height)
 483 {
 484         if (float(width) * aspect_denom >= float(height) * aspect_nom) {
 485                 // Same aspect, or W/H > aspect (image is wider than the frame).
 486                 // In either case, keep width.
 487                 return width;
 488         } else {
 489                 // W/H < aspect (image is taller than the frame), so keep height,
 490                 // and adjust width correspondingly.
 491                 return lrintf(height * aspect_nom / aspect_denom);
 492         }
 493 }
 494
 495 // Propagate input texture sizes throughout, and inform effects downstream.
 496 // (Like a lot of other code, we depend on effects being in topological order.)
 497 void EffectChain::inform_input_sizes(Phase *phase)
 498 {
 499         // All effects that have a defined size (inputs and RTT inputs)
 500         // get that. Reset all others.
 501         for (unsigned i = 0; i < phase->effects.size(); ++i) {
 502                 Node *node = phase->effects[i];
 503                 if (node->effect->num_inputs() == 0) {
 504                         Input *input = static_cast<Input *>(node->effect);
 505                         node->output_width = input->get_width();
 506                         node->output_height = input->get_height();
 507                         assert(node->output_width != 0);
 508                         assert(node->output_height != 0);
 509                 } else {
 510                         node->output_width = node->output_height = 0;
 511                 }
 512         }
 513         for (unsigned i = 0; i < phase->inputs.size(); ++i) {
 514                 Node *input = phase->inputs[i];
 515                 input->output_width = input->phase->output_width;
 516                 input->output_height = input->phase->output_height;
 517                 assert(input->output_width != 0);
 518                 assert(input->output_height != 0);
 519         }
 520
 521         // Now propagate from the inputs towards the end, and inform as we go.
 522         // The rules are simple:
 523         //
 524         //   1. Don't touch effects that already have given sizes (ie., inputs).
 525         //   2. If all of your inputs have the same size, that will be your output size.
 526         //   3. Otherwise, your output size is 0x0.
 527         for (unsigned i = 0; i < phase->effects.size(); ++i) {
 528                 Node *node = phase->effects[i];
 529                 if (node->effect->num_inputs() == 0) {
 530                         continue;
 531                 }
 532                 unsigned this_output_width = 0;
 533                 unsigned this_output_height = 0;
 534                 for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 535                         Node *input = node->incoming_links[j];
 536                         node->effect->inform_input_size(j, input->output_width, input->output_height);
 537                         if (j == 0) {
 538                                 this_output_width = input->output_width;
 539                                 this_output_height = input->output_height;
 540                         } else if (input->output_width != this_output_width || input->output_height != this_output_height) {
 541                                 // Inputs disagree.
 542                                 this_output_width = 0;
 543                                 this_output_height = 0;
 544                         }
 545                 }
 546                 node->output_width = this_output_width;
 547                 node->output_height = this_output_height;
 548         }
 549 }
 550
 551 // Note: You should call inform_input_sizes() before this, as the last effect's
 552 // desired output size might change based on the inputs.
 553 void EffectChain::find_output_size(Phase *phase)
 554 {
 555         Node *output_node = phase->effects.back();
 556
 557         // If the last effect explicitly sets an output size, use that.
 558         if (output_node->effect->changes_output_size()) {
 559                 output_node->effect->get_output_size(&phase->output_width, &phase->output_height);
 560                 return;
 561         }
 562
 563         // If not, look at the input phases and textures.
 564         // We select the largest one (by fit into the current aspect).
 565         unsigned best_width = 0;
 566         for (unsigned i = 0; i < phase->inputs.size(); ++i) {
 567                 Node *input = phase->inputs[i];
 568                 assert(input->phase->output_width != 0);
 569                 assert(input->phase->output_height != 0);
 570                 unsigned width = fit_rectangle_to_aspect(input->phase->output_width, input->phase->output_height);
 571                 if (width > best_width) {
 572                         best_width = width;
 573                 }
 574         }
 575         for (unsigned i = 0; i < phase->effects.size(); ++i) {
 576                 Effect *effect = phase->effects[i]->effect;
 577                 if (effect->num_inputs() != 0) {
 578                         continue;
 579                 }
 580
 581                 Input *input = static_cast<Input *>(effect);
 582                 unsigned width = fit_rectangle_to_aspect(input->get_width(), input->get_height());
 583                 if (width > best_width) {
 584                         best_width = width;
 585                 }
 586         }
 587         assert(best_width != 0);
 588         phase->output_width = best_width;
 589         phase->output_height = best_width * aspect_denom / aspect_nom;
 590 }
 591
 592 void EffectChain::sort_nodes_topologically()
 593 {
 594         std::set<Node *> visited_nodes;
 595         std::vector<Node *> sorted_list;
 596         for (unsigned i = 0; i < nodes.size(); ++i) {
 597                 if (nodes[i]->incoming_links.size() == 0) {
 598                         topological_sort_visit_node(nodes[i], &visited_nodes, &sorted_list);
 599                 }
 600         }
 601         reverse(sorted_list.begin(), sorted_list.end());
 602         nodes = sorted_list;
 603 }
 604
 605 void EffectChain::topological_sort_visit_node(Node *node, std::set<Node *> *visited_nodes, std::vector<Node *> *sorted_list)
 606 {
 607         if (visited_nodes->count(node) != 0) {
 608                 return;
 609         }
 610         visited_nodes->insert(node);
 611         for (unsigned i = 0; i < node->outgoing_links.size(); ++i) {
 612                 topological_sort_visit_node(node->outgoing_links[i], visited_nodes, sorted_list);
 613         }
 614         sorted_list->push_back(node);
 615 }
 616
 617 // Propagate gamma and color space information as far as we can in the graph.
 618 // The rules are simple: Anything where all the inputs agree, get that as
 619 // output as well. Anything else keeps having *_INVALID.
 620 void EffectChain::propagate_gamma_and_color_space()
 621 {
 622         // We depend on going through the nodes in order.
 623         sort_nodes_topologically();
 624
 625         for (unsigned i = 0; i < nodes.size(); ++i) {
 626                 Node *node = nodes[i];
 627                 if (node->disabled) {
 628                         continue;
 629                 }
 630                 assert(node->incoming_links.size() == node->effect->num_inputs());
 631                 if (node->incoming_links.size() == 0) {
 632                         assert(node->output_color_space != COLORSPACE_INVALID);
 633                         assert(node->output_gamma_curve != GAMMA_INVALID);
 634                         continue;
 635                 }
 636
 637                 ColorSpace color_space = node->incoming_links[0]->output_color_space;
 638                 GammaCurve gamma_curve = node->incoming_links[0]->output_gamma_curve;
 639                 for (unsigned j = 1; j < node->incoming_links.size(); ++j) {
 640                         if (node->incoming_links[j]->output_color_space != color_space) {
 641                                 color_space = COLORSPACE_INVALID;
 642                         }
 643                         if (node->incoming_links[j]->output_gamma_curve != gamma_curve) {
 644                                 gamma_curve = GAMMA_INVALID;
 645                         }
 646                 }
 647
 648                 // The conversion effects already have their outputs set correctly,
 649                 // so leave them alone.
 650                 if (node->effect->effect_type_id() != "ColorSpaceConversionEffect") {
 651                         node->output_color_space = color_space;
 652                 }
 653                 if (node->effect->effect_type_id() != "GammaCompressionEffect" &&
 654                     node->effect->effect_type_id() != "GammaExpansionEffect") {
 655                         node->output_gamma_curve = gamma_curve;
 656                 }
 657         }
 658 }
 659
 660 bool EffectChain::node_needs_colorspace_fix(Node *node)
 661 {
 662         if (node->disabled) {
 663                 return false;
 664         }
 665         if (node->effect->num_inputs() == 0) {
 666                 return false;
 667         }
 668
 669         // propagate_gamma_and_color_space() has already set our output
 670         // to COLORSPACE_INVALID if the inputs differ, so we can rely on that.
 671         if (node->output_color_space == COLORSPACE_INVALID) {
 672                 return true;
 673         }
 674         return (node->effect->needs_srgb_primaries() && node->output_color_space != COLORSPACE_sRGB);
 675 }
 676
 677 // Fix up color spaces so that there are no COLORSPACE_INVALID nodes left in
 678 // the graph. Our strategy is not always optimal, but quite simple:
 679 // Find an effect that's as early as possible where the inputs are of
 680 // unacceptable colorspaces (that is, either different, or, if the effect only
 681 // wants sRGB, not sRGB.) Add appropriate conversions on all its inputs,
 682 // propagate the information anew, and repeat until there are no more such
 683 // effects.
 684 void EffectChain::fix_internal_color_spaces()
 685 {
 686         unsigned colorspace_propagation_pass = 0;
 687         bool found_any;
 688         do {
 689                 found_any = false;
 690                 for (unsigned i = 0; i < nodes.size(); ++i) {
 691                         Node *node = nodes[i];
 692                         if (!node_needs_colorspace_fix(node)) {
 693                                 continue;
 694                         }
 695
 696                         // Go through each input that is not sRGB, and insert
 697                         // a colorspace conversion before it.
 698                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 699                                 Node *input = node->incoming_links[j];
 700                                 assert(input->output_color_space != COLORSPACE_INVALID);
 701                                 if (input->output_color_space == COLORSPACE_sRGB) {
 702                                         continue;
 703                                 }
 704                                 Node *conversion = add_node(new ColorSpaceConversionEffect());
 705                                 conversion->effect->set_int("source_space", input->output_color_space);
 706                                 conversion->effect->set_int("destination_space", COLORSPACE_sRGB);
 707                                 conversion->output_color_space = COLORSPACE_sRGB;
 708                                 insert_node_between(input, conversion, node);
 709                         }
 710
 711                         // Re-sort topologically, and propagate the new information.
 712                         propagate_gamma_and_color_space();
 713
 714                         found_any = true;
 715                         break;
 716                 }
 717
 718                 char filename[256];
 719                 sprintf(filename, "step3-colorspacefix-iter%u.dot", ++colorspace_propagation_pass);
 720                 output_dot(filename);
 721                 assert(colorspace_propagation_pass < 100);
 722         } while (found_any);
 723
 724         for (unsigned i = 0; i < nodes.size(); ++i) {
 725                 Node *node = nodes[i];
 726                 if (node->disabled) {
 727                         continue;
 728                 }
 729                 assert(node->output_color_space != COLORSPACE_INVALID);
 730         }
 731 }
 732
 733 // Make so that the output is in the desired color space.
 734 void EffectChain::fix_output_color_space()
 735 {
 736         Node *output = find_output_node();
 737         if (output->output_color_space != output_format.color_space) {
 738                 Node *conversion = add_node(new ColorSpaceConversionEffect());
 739                 conversion->effect->set_int("source_space", output->output_color_space);
 740                 conversion->effect->set_int("destination_space", output_format.color_space);
 741                 conversion->output_color_space = output_format.color_space;
 742                 connect_nodes(output, conversion);
 743         }
 744 }
 745
 746 bool EffectChain::node_needs_gamma_fix(Node *node)
 747 {
 748         if (node->disabled) {
 749                 return false;
 750         }
 751
 752         // Small hack since the output is not an explicit node:
 753         // If we are the last node and our output is in the wrong
 754         // space compared to EffectChain's output, we need to fix it.
 755         // This will only take us to linear, but fix_output_gamma()
 756         // will come and take us to the desired output gamma
 757         // if it is needed.
 758         //
 759         // This needs to be before everything else, since it could
 760         // even apply to inputs (if they are the only effect).
 761         if (node->outgoing_links.empty() &&
 762             node->output_gamma_curve != output_format.gamma_curve &&
 763             node->output_gamma_curve != GAMMA_LINEAR) {
 764                 return true;
 765         }
 766
 767         if (node->effect->num_inputs() == 0) {
 768                 return false;
 769         }
 770
 771         // propagate_gamma_and_color_space() has already set our output
 772         // to GAMMA_INVALID if the inputs differ, so we can rely on that,
 773         // except for GammaCompressionEffect.
 774         if (node->output_gamma_curve == GAMMA_INVALID) {
 775                 return true;
 776         }
 777         if (node->effect->effect_type_id() == "GammaCompressionEffect") {
 778                 assert(node->incoming_links.size() == 1);
 779                 return node->incoming_links[0]->output_gamma_curve != GAMMA_LINEAR;
 780         }
 781
 782         return (node->effect->needs_linear_light() && node->output_gamma_curve != GAMMA_LINEAR);
 783 }
 784
 785 // Very similar to fix_internal_color_spaces(), but for gamma.
 786 // There is one difference, though; before we start adding conversion nodes,
 787 // we see if we can get anything out of asking the sources to deliver
 788 // linear gamma directly. fix_internal_gamma_by_asking_inputs()
 789 // does that part, while fix_internal_gamma_by_inserting_nodes()
 790 // inserts nodes as needed afterwards.
 791 void EffectChain::fix_internal_gamma_by_asking_inputs(unsigned step)
 792 {
 793         unsigned gamma_propagation_pass = 0;
 794         bool found_any;
 795         do {
 796                 found_any = false;
 797                 for (unsigned i = 0; i < nodes.size(); ++i) {
 798                         Node *node = nodes[i];
 799                         if (!node_needs_gamma_fix(node)) {
 800                                 continue;
 801                         }
 802
 803                         // See if all inputs can give us linear gamma. If not, leave it.
 804                         std::vector<Node *> nonlinear_inputs;
 805                         find_all_nonlinear_inputs(node, &nonlinear_inputs);
 806                         assert(!nonlinear_inputs.empty());
 807
 808                         bool all_ok = true;
 809                         for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
 810                                 Input *input = static_cast<Input *>(nonlinear_inputs[i]->effect);
 811                                 all_ok &= input->can_output_linear_gamma();
 812                         }
 813
 814                         if (!all_ok) {
 815                                 continue;
 816                         }
 817
 818                         for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
 819                                 nonlinear_inputs[i]->effect->set_int("output_linear_gamma", 1);
 820                                 nonlinear_inputs[i]->output_gamma_curve = GAMMA_LINEAR;
 821                         }
 822
 823                         // Re-sort topologically, and propagate the new information.
 824                         propagate_gamma_and_color_space();
 825
 826                         found_any = true;
 827                         break;
 828                 }
 829
 830                 char filename[256];
 831                 sprintf(filename, "step%u-gammafix-iter%u.dot", step, ++gamma_propagation_pass);
 832                 output_dot(filename);
 833                 assert(gamma_propagation_pass < 100);
 834         } while (found_any);
 835 }
 836
 837 void EffectChain::fix_internal_gamma_by_inserting_nodes(unsigned step)
 838 {
 839         unsigned gamma_propagation_pass = 0;
 840         bool found_any;
 841         do {
 842                 found_any = false;
 843                 for (unsigned i = 0; i < nodes.size(); ++i) {
 844                         Node *node = nodes[i];
 845                         if (!node_needs_gamma_fix(node)) {
 846                                 continue;
 847                         }
 848
 849                         // Special case: We could be an input and still be asked to
 850                         // fix our gamma; if so, we should be the only node
 851                         // (as node_needs_gamma_fix() would only return true in
 852                         // for an input in that case). That means we should insert
 853                         // a conversion node _after_ ourselves.
 854                         if (node->incoming_links.empty()) {
 855                                 assert(node->outgoing_links.empty());
 856                                 Node *conversion = add_node(new GammaExpansionEffect());
 857                                 conversion->effect->set_int("source_curve", node->output_gamma_curve);
 858                                 conversion->output_gamma_curve = GAMMA_LINEAR;
 859                                 connect_nodes(node, conversion);
 860                         }
 861
 862                         // If not, go through each input that is not linear gamma,
 863                         // and insert a gamma conversion before it.
 864                         for (unsigned j = 0; j < node->incoming_links.size(); ++j) {
 865                                 Node *input = node->incoming_links[j];
 866                                 assert(input->output_gamma_curve != GAMMA_INVALID);
 867                                 if (input->output_gamma_curve == GAMMA_LINEAR) {
 868                                         continue;
 869                                 }
 870                                 Node *conversion = add_node(new GammaExpansionEffect());
 871                                 conversion->effect->set_int("source_curve", input->output_gamma_curve);
 872                                 conversion->output_gamma_curve = GAMMA_LINEAR;
 873                                 insert_node_between(input, conversion, node);
 874                         }
 875
 876                         // Re-sort topologically, and propagate the new information.
 877                         propagate_gamma_and_color_space();
 878
 879                         found_any = true;
 880                         break;
 881                 }
 882
 883                 char filename[256];
 884                 sprintf(filename, "step%u-gammafix-iter%u.dot", step, ++gamma_propagation_pass);
 885                 output_dot(filename);
 886                 assert(gamma_propagation_pass < 100);
 887         } while (found_any);
 888
 889         for (unsigned i = 0; i < nodes.size(); ++i) {
 890                 Node *node = nodes[i];
 891                 if (node->disabled) {
 892                         continue;
 893                 }
 894                 assert(node->output_gamma_curve != GAMMA_INVALID);
 895         }
 896 }
 897
 898 // Make so that the output is in the desired gamma.
 899 // Note that this assumes linear input gamma, so it might create the need
 900 // for another pass of fix_internal_gamma().
 901 void EffectChain::fix_output_gamma()
 902 {
 903         Node *output = find_output_node();
 904         if (output->output_gamma_curve != output_format.gamma_curve) {
 905                 Node *conversion = add_node(new GammaCompressionEffect());
 906                 conversion->effect->set_int("destination_curve", output_format.gamma_curve);
 907                 conversion->output_gamma_curve = output_format.gamma_curve;
 908                 connect_nodes(output, conversion);
 909         }
 910 }
 911
 912 // Find the output node. This is, simply, one that has no outgoing links.
 913 // If there are multiple ones, the graph is malformed (we do not support
 914 // multiple outputs right now).
 915 Node *EffectChain::find_output_node()
 916 {
 917         std::vector<Node *> output_nodes;
 918         for (unsigned i = 0; i < nodes.size(); ++i) {
 919                 Node *node = nodes[i];
 920                 if (node->disabled) {
 921                         continue;
 922                 }
 923                 if (node->outgoing_links.empty()) {
 924                         output_nodes.push_back(node);
 925                 }
 926         }
 927         assert(output_nodes.size() == 1);
 928         return output_nodes[0];
 929 }
 930
 931 void EffectChain::finalize()
 932 {
 933         // Output the graph as it is before we do any conversions on it.
 934         output_dot("step0-start.dot");
 935
 936         // Give each effect in turn a chance to rewrite its own part of the graph.
 937         // Note that if more effects are added as part of this, they will be
 938         // picked up as part of the same for loop, since they are added at the end.
 939         for (unsigned i = 0; i < nodes.size(); ++i) {
 940                 nodes[i]->effect->rewrite_graph(this, nodes[i]);
 941         }
 942         output_dot("step1-rewritten.dot");
 943
 944         propagate_gamma_and_color_space();
 945         output_dot("step2-propagated.dot");
 946
 947         fix_internal_color_spaces();
 948         fix_output_color_space();
 949         output_dot("step4-output-colorspacefix.dot");
 950
 951         // Note that we need to fix gamma after colorspace conversion,
 952         // because colorspace conversions might create needs for gamma conversions.
 953         // Also, we need to run an extra pass of fix_internal_gamma() after
 954         // fixing the output gamma, as we only have conversions to/from linear.
 955         fix_internal_gamma_by_asking_inputs(5);
 956         fix_internal_gamma_by_inserting_nodes(6);
 957         fix_output_gamma();
 958         output_dot("step7-output-gammafix.dot");
 959         fix_internal_gamma_by_asking_inputs(8);
 960         fix_internal_gamma_by_inserting_nodes(9);
 961
 962         output_dot("step10-final.dot");
 963
 964         // Construct all needed GLSL programs, starting at the output.
 965         construct_glsl_programs(find_output_node());
 966
 967         output_dot("step11-split-to-phases.dot");
 968
 969         // If we have more than one phase, we need intermediate render-to-texture.
 970         // Construct an FBO, and then as many textures as we need.
 971         // We choose the simplest option of having one texture per output,
 972         // since otherwise this turns into an (albeit simple)
 973         // register allocation problem.
 974         if (phases.size() > 1) {
 975                 glGenFramebuffers(1, &fbo);
 976
 977                 for (unsigned i = 0; i < phases.size() - 1; ++i) {
 978                         inform_input_sizes(phases[i]);
 979                         find_output_size(phases[i]);
 980
 981                         Node *output_node = phases[i]->effects.back();
 982                         glGenTextures(1, &output_node->output_texture);
 983                         check_error();
 984                         glBindTexture(GL_TEXTURE_2D, output_node->output_texture);
 985                         check_error();
 986                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 987                         check_error();
 988                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 989                         check_error();
 990                         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F_ARB, phases[i]->output_width, phases[i]->output_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 991                         check_error();
 992
 993                         output_node->output_texture_width = phases[i]->output_width;
 994                         output_node->output_texture_height = phases[i]->output_height;
 995                 }
 996                 inform_input_sizes(phases.back());
 997         }
 998
 999         for (unsigned i = 0; i < inputs.size(); ++i) {
1000                 inputs[i]->finalize();
1001         }
1002
1003         assert(phases[0]->inputs.empty());
1004
1005         finalized = true;
1006 }
1007
1008 void EffectChain::render_to_fbo(GLuint dest_fbo, unsigned width, unsigned height)
1009 {
1010         assert(finalized);
1011
1012         // Save original viewport.
1013         GLuint x = 0, y = 0;
1014
1015         if (width == 0 && height == 0) {
1016                 GLint viewport[4];
1017                 glGetIntegerv(GL_VIEWPORT, viewport);
1018                 x = viewport[0];
1019                 y = viewport[1];
1020                 width = viewport[2];
1021                 height = viewport[3];
1022         }
1023
1024         // Basic state.
1025         glDisable(GL_BLEND);
1026         check_error();
1027         glDisable(GL_DEPTH_TEST);
1028         check_error();
1029         glDepthMask(GL_FALSE);
1030         check_error();
1031
1032         glMatrixMode(GL_PROJECTION);
1033         glLoadIdentity();
1034         glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
1035
1036         glMatrixMode(GL_MODELVIEW);
1037         glLoadIdentity();
1038
1039         if (phases.size() > 1) {
1040                 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
1041                 check_error();
1042         }
1043
1044         std::set<Node *> generated_mipmaps;
1045
1046         for (unsigned phase = 0; phase < phases.size(); ++phase) {
1047                 // See if the requested output size has changed. If so, we need to recreate
1048                 // the texture (and before we start setting up inputs).
1049                 inform_input_sizes(phases[phase]);
1050                 if (phase != phases.size() - 1) {
1051                         find_output_size(phases[phase]);
1052
1053                         Node *output_node = phases[phase]->effects.back();
1054
1055                         if (output_node->output_texture_width != phases[phase]->output_width ||
1056                             output_node->output_texture_height != phases[phase]->output_height) {
1057                                 glActiveTexture(GL_TEXTURE0);
1058                                 check_error();
1059                                 glBindTexture(GL_TEXTURE_2D, output_node->output_texture);
1060                                 check_error();
1061                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F_ARB, phases[phase]->output_width, phases[phase]->output_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
1062                                 check_error();
1063                                 glBindTexture(GL_TEXTURE_2D, 0);
1064                                 check_error();
1065
1066                                 output_node->output_texture_width = phases[phase]->output_width;
1067                                 output_node->output_texture_height = phases[phase]->output_height;
1068                         }
1069                 }
1070
1071                 glUseProgram(phases[phase]->glsl_program_num);
1072                 check_error();
1073
1074                 // Set up RTT inputs for this phase.
1075                 for (unsigned sampler = 0; sampler < phases[phase]->inputs.size(); ++sampler) {
1076                         glActiveTexture(GL_TEXTURE0 + sampler);
1077                         Node *input = phases[phase]->inputs[sampler];
1078                         glBindTexture(GL_TEXTURE_2D, input->output_texture);
1079                         check_error();
1080                         if (phases[phase]->input_needs_mipmaps) {
1081                                 if (generated_mipmaps.count(input) == 0) {
1082                                         glGenerateMipmap(GL_TEXTURE_2D);
1083                                         check_error();
1084                                         generated_mipmaps.insert(input);
1085                                 }
1086                                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
1087                                 check_error();
1088                         } else {
1089                                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
1090                                 check_error();
1091                         }
1092
1093                         std::string texture_name = std::string("tex_") + input->effect_id;
1094                         glUniform1i(glGetUniformLocation(phases[phase]->glsl_program_num, texture_name.c_str()), sampler);
1095                         check_error();
1096                 }
1097
1098                 // And now the output.
1099                 if (phase == phases.size() - 1) {
1100                         // Last phase goes to the output the user specified.
1101                         glBindFramebuffer(GL_FRAMEBUFFER, dest_fbo);
1102                         check_error();
1103                         glViewport(x, y, width, height);
1104                 } else {
1105                         Node *output_node = phases[phase]->effects.back();
1106                         glFramebufferTexture2D(
1107                                 GL_FRAMEBUFFER,
1108                                 GL_COLOR_ATTACHMENT0,
1109                                 GL_TEXTURE_2D,
1110                                 output_node->output_texture,
1111                                 0);
1112                         check_error();
1113                         glViewport(0, 0, phases[phase]->output_width, phases[phase]->output_height);
1114                 }
1115
1116                 // Give the required parameters to all the effects.
1117                 unsigned sampler_num = phases[phase]->inputs.size();
1118                 for (unsigned i = 0; i < phases[phase]->effects.size(); ++i) {
1119                         Node *node = phases[phase]->effects[i];
1120                         node->effect->set_gl_state(phases[phase]->glsl_program_num, node->effect_id, &sampler_num);
1121                         check_error();
1122                 }
1123
1124                 // Now draw!
1125                 glBegin(GL_QUADS);
1126
1127                 glTexCoord2f(0.0f, 0.0f);
1128                 glVertex2f(0.0f, 0.0f);
1129
1130                 glTexCoord2f(1.0f, 0.0f);
1131                 glVertex2f(1.0f, 0.0f);
1132
1133                 glTexCoord2f(1.0f, 1.0f);
1134                 glVertex2f(1.0f, 1.0f);
1135
1136                 glTexCoord2f(0.0f, 1.0f);
1137                 glVertex2f(0.0f, 1.0f);
1138
1139                 glEnd();
1140                 check_error();
1141
1142                 for (unsigned i = 0; i < phases[phase]->effects.size(); ++i) {
1143                         Node *node = phases[phase]->effects[i];
1144                         node->effect->clear_gl_state();
1145                 }
1146         }
1147 }