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

   1 #define GL_GLEXT_PROTOTYPES 1
   2
   3 #include <stdio.h>
   4 #include <string.h>
   5 #include <assert.h>
   6
   7 #include <algorithm>
   8 #include <set>
   9 #include <stack>
  10 #include <vector>
  11
  12 #include "util.h"
  13 #include "effect_chain.h"
  14 #include "gamma_expansion_effect.h"
  15 #include "gamma_compression_effect.h"
  16 #include "colorspace_conversion_effect.h"
  17 #include "input.h"
  18 #include "opengl.h"
  19
  20 EffectChain::EffectChain(unsigned width, unsigned height)
  21         : width(width),
  22           height(height),
  23           finalized(false) {}
  24
  25 Input *EffectChain::add_input(Input *input)
  26 {
  27         char eff_id[256];
  28         sprintf(eff_id, "src_image%u", (unsigned)inputs.size());
  29
  30         effects.push_back(input);
  31         inputs.push_back(input);
  32         output_color_space.insert(std::make_pair(input, input->get_color_space()));
  33         output_gamma_curve.insert(std::make_pair(input, input->get_gamma_curve()));
  34         effect_ids.insert(std::make_pair(input, eff_id));
  35         incoming_links.insert(std::make_pair(input, std::vector<Effect *>()));
  36         return input;
  37 }
  38
  39 void EffectChain::add_output(const ImageFormat &format)
  40 {
  41         output_format = format;
  42 }
  43
  44 void EffectChain::add_effect_raw(Effect *effect, const std::vector<Effect *> &inputs)
  45 {
  46         char effect_id[256];
  47         sprintf(effect_id, "eff%u", (unsigned)effects.size());
  48
  49         effects.push_back(effect);
  50         effect_ids.insert(std::make_pair(effect, effect_id));
  51         assert(inputs.size() == effect->num_inputs());
  52         for (unsigned i = 0; i < inputs.size(); ++i) {
  53                 assert(std::find(effects.begin(), effects.end(), inputs[i]) != effects.end());
  54                 outgoing_links[inputs[i]].push_back(effect);
  55         }
  56         incoming_links.insert(std::make_pair(effect, inputs));
  57         output_gamma_curve[effect] = output_gamma_curve[last_added_effect()];
  58         output_color_space[effect] = output_color_space[last_added_effect()];
  59 }
  60
  61 void EffectChain::find_all_nonlinear_inputs(Effect *effect,
  62                                             std::vector<Input *> *nonlinear_inputs,
  63                                             std::vector<Effect *> *intermediates)
  64 {
  65         assert(output_gamma_curve.count(effect) != 0);
  66         if (output_gamma_curve[effect] == GAMMA_LINEAR) {
  67                 return;
  68         }
  69         if (effect->num_inputs() == 0) {
  70                 nonlinear_inputs->push_back(static_cast<Input *>(effect));
  71         } else {
  72                 intermediates->push_back(effect);
  73
  74                 assert(incoming_links.count(effect) == 1);
  75                 std::vector<Effect *> deps = incoming_links[effect];
  76                 assert(effect->num_inputs() == deps.size());
  77                 for (unsigned i = 0; i < deps.size(); ++i) {
  78                         find_all_nonlinear_inputs(deps[i], nonlinear_inputs, intermediates);
  79                 }
  80         }
  81 }
  82
  83 Effect *EffectChain::normalize_to_linear_gamma(Effect *input)
  84 {
  85         // Find out if all the inputs can be set to deliver sRGB inputs.
  86         // If so, we can just ask them to do that instead of inserting a
  87         // (possibly expensive) conversion operation.
  88         //
  89         // NOTE: We assume that effects generally don't mess with the gamma
  90         // curve (except GammaCompressionEffect, which should never be
  91         // inserted into a chain when this is called), so that we can just
  92         // update the output gamma as we go.
  93         //
  94         // TODO: Setting this flag for one source might confuse a different
  95         // part of the pipeline using the same source.
  96         std::vector<Input *> nonlinear_inputs;
  97         std::vector<Effect *> intermediates;
  98         find_all_nonlinear_inputs(input, &nonlinear_inputs, &intermediates);
  99
 100         bool all_ok = true;
 101         for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
 102                 all_ok &= nonlinear_inputs[i]->can_output_linear_gamma();
 103         }
 104
 105         if (all_ok) {
 106                 for (unsigned i = 0; i < nonlinear_inputs.size(); ++i) {
 107                         bool ok = nonlinear_inputs[i]->set_int("output_linear_gamma", 1);
 108                         assert(ok);
 109                         output_gamma_curve[nonlinear_inputs[i]] = GAMMA_LINEAR;
 110                 }
 111                 for (unsigned i = 0; i < intermediates.size(); ++i) {
 112                         output_gamma_curve[intermediates[i]] = GAMMA_LINEAR;
 113                 }
 114                 return input;
 115         }
 116
 117         // OK, that didn't work. Insert a conversion effect.
 118         GammaExpansionEffect *gamma_conversion = new GammaExpansionEffect();
 119         gamma_conversion->set_int("source_curve", output_gamma_curve[input]);
 120         std::vector<Effect *> inputs;
 121         inputs.push_back(input);
 122         gamma_conversion->add_self_to_effect_chain(this, inputs);
 123         output_gamma_curve[gamma_conversion] = GAMMA_LINEAR;
 124         return gamma_conversion;
 125 }
 126
 127 Effect *EffectChain::normalize_to_srgb(Effect *input)
 128 {
 129         assert(output_gamma_curve.count(input) != 0);
 130         assert(output_color_space.count(input) != 0);
 131         assert(output_gamma_curve[input] == GAMMA_LINEAR);
 132         ColorSpaceConversionEffect *colorspace_conversion = new ColorSpaceConversionEffect();
 133         colorspace_conversion->set_int("source_space", output_color_space[input]);
 134         colorspace_conversion->set_int("destination_space", COLORSPACE_sRGB);
 135         std::vector<Effect *> inputs;
 136         inputs.push_back(input);
 137         colorspace_conversion->add_self_to_effect_chain(this, inputs);
 138         output_color_space[colorspace_conversion] = COLORSPACE_sRGB;
 139         return colorspace_conversion;
 140 }
 141
 142 Effect *EffectChain::add_effect(Effect *effect, const std::vector<Effect *> &inputs)
 143 {
 144         assert(inputs.size() == effect->num_inputs());
 145
 146         std::vector<Effect *> normalized_inputs = inputs;
 147         for (unsigned i = 0; i < normalized_inputs.size(); ++i) {
 148                 assert(output_gamma_curve.count(normalized_inputs[i]) != 0);
 149                 if (effect->needs_linear_light() && output_gamma_curve[normalized_inputs[i]] != GAMMA_LINEAR) {
 150                         normalized_inputs[i] = normalize_to_linear_gamma(normalized_inputs[i]);
 151                 }
 152                 assert(output_color_space.count(normalized_inputs[i]) != 0);
 153                 if (effect->needs_srgb_primaries() && output_color_space[normalized_inputs[i]] != COLORSPACE_sRGB) {
 154                         normalized_inputs[i] = normalize_to_srgb(normalized_inputs[i]);
 155                 }
 156         }
 157
 158         effect->add_self_to_effect_chain(this, normalized_inputs);
 159         return effect;
 160 }
 161
 162 // GLSL pre-1.30 doesn't support token pasting. Replace PREFIX(x) with <effect_id>_x.
 163 std::string replace_prefix(const std::string &text, const std::string &prefix)
 164 {
 165         std::string output;
 166         size_t start = 0;
 167
 168         while (start < text.size()) {
 169                 size_t pos = text.find("PREFIX(", start);
 170                 if (pos == std::string::npos) {
 171                         output.append(text.substr(start, std::string::npos));
 172                         break;
 173                 }
 174
 175                 output.append(text.substr(start, pos - start));
 176                 output.append(prefix);
 177                 output.append("_");
 178
 179                 pos += strlen("PREFIX(");
 180
 181                 // Output stuff until we find the matching ), which we then eat.
 182                 int depth = 1;
 183                 size_t end_arg_pos = pos;
 184                 while (end_arg_pos < text.size()) {
 185                         if (text[end_arg_pos] == '(') {
 186                                 ++depth;
 187                         } else if (text[end_arg_pos] == ')') {
 188                                 --depth;
 189                                 if (depth == 0) {
 190                                         break;
 191                                 }
 192                         }
 193                         ++end_arg_pos;
 194                 }
 195                 output.append(text.substr(pos, end_arg_pos - pos));
 196                 ++end_arg_pos;
 197                 assert(depth == 0);
 198                 start = end_arg_pos;
 199         }
 200         return output;
 201 }
 202
 203 EffectChain::Phase *EffectChain::compile_glsl_program(const std::vector<Effect *> &inputs, const std::vector<Effect *> &effects)
 204 {
 205         assert(!effects.empty());
 206
 207         // Deduplicate the inputs.
 208         std::vector<Effect *> true_inputs = inputs;
 209         std::sort(true_inputs.begin(), true_inputs.end());
 210         true_inputs.erase(std::unique(true_inputs.begin(), true_inputs.end()), true_inputs.end());
 211
 212         bool input_needs_mipmaps = false;
 213         std::string frag_shader = read_file("header.frag");
 214
 215         // Create functions for all the texture inputs that we need.
 216         for (unsigned i = 0; i < true_inputs.size(); ++i) {
 217                 Effect *effect = true_inputs[i];
 218                 assert(effect_ids.count(effect) != 0);
 219                 std::string effect_id = effect_ids[effect];
 220
 221                 frag_shader += std::string("uniform sampler2D tex_") + effect_id + ";\n";
 222                 frag_shader += std::string("vec4 ") + effect_id + "(vec2 tc) {\n";
 223                 frag_shader += "\treturn texture2D(tex_" + effect_id + ", tc);\n";
 224                 frag_shader += "}\n";
 225                 frag_shader += "\n";
 226         }
 227
 228         std::string last_effect_id;
 229         for (unsigned i = 0; i < effects.size(); ++i) {
 230                 Effect *effect = effects[i];
 231                 assert(effect != NULL);
 232                 assert(effect_ids.count(effect) != 0);
 233                 std::string effect_id = effect_ids[effect];
 234                 last_effect_id = effect_id;
 235
 236                 if (incoming_links[effect].size() == 1) {
 237                         frag_shader += std::string("#define INPUT ") + effect_ids[incoming_links[effect][0]] + "\n";
 238                 } else {
 239                         for (unsigned j = 0; j < incoming_links[effect].size(); ++j) {
 240                                 char buf[256];
 241                                 sprintf(buf, "#define INPUT%d %s\n", j + 1, effect_ids[incoming_links[effect][j]].c_str());
 242                                 frag_shader += buf;
 243                         }
 244                 }
 245
 246                 frag_shader += "\n";
 247                 frag_shader += std::string("#define FUNCNAME ") + effect_id + "\n";
 248                 frag_shader += replace_prefix(effect->output_convenience_uniforms(), effect_id);
 249                 frag_shader += replace_prefix(effect->output_fragment_shader(), effect_id);
 250                 frag_shader += "#undef PREFIX\n";
 251                 frag_shader += "#undef FUNCNAME\n";
 252                 if (incoming_links[effect].size() == 1) {
 253                         frag_shader += "#undef INPUT\n";
 254                 } else {
 255                         for (unsigned j = 0; j < incoming_links[effect].size(); ++j) {
 256                                 char buf[256];
 257                                 sprintf(buf, "#undef INPUT%d\n", j + 1);
 258                                 frag_shader += buf;
 259                         }
 260                 }
 261                 frag_shader += "\n";
 262
 263                 input_needs_mipmaps |= effect->needs_mipmaps();
 264         }
 265         for (unsigned i = 0; i < effects.size(); ++i) {
 266                 Effect *effect = effects[i];
 267                 if (effect->num_inputs() == 0) {
 268                         effect->set_int("needs_mipmaps", input_needs_mipmaps);
 269                 }
 270         }
 271         assert(!last_effect_id.empty());
 272         frag_shader += std::string("#define INPUT ") + last_effect_id + "\n";
 273         frag_shader.append(read_file("footer.frag"));
 274         printf("%s\n", frag_shader.c_str());
 275
 276         GLuint glsl_program_num = glCreateProgram();
 277         GLuint vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 278         GLuint fs_obj = compile_shader(frag_shader, GL_FRAGMENT_SHADER);
 279         glAttachShader(glsl_program_num, vs_obj);
 280         check_error();
 281         glAttachShader(glsl_program_num, fs_obj);
 282         check_error();
 283         glLinkProgram(glsl_program_num);
 284         check_error();
 285
 286         Phase *phase = new Phase;
 287         phase->glsl_program_num = glsl_program_num;
 288         phase->input_needs_mipmaps = input_needs_mipmaps;
 289         phase->inputs = true_inputs;
 290         phase->effects = effects;
 291
 292         return phase;
 293 }
 294
 295 // Construct GLSL programs, starting at the given effect and following
 296 // the chain from there. We end a program every time we come to an effect
 297 // marked as "needs texture bounce", one that is used by multiple other
 298 // effects, every time an effect wants to change the output size,
 299 // and of course at the end.
 300 //
 301 // We follow a quite simple depth-first search from the output, although
 302 // without any explicit recursion.
 303 void EffectChain::construct_glsl_programs(Effect *output)
 304 {
 305         // Which effects have already been completed in this phase?
 306         // We need to keep track of it, as an effect with multiple outputs
 307         // could otherwise be calculate multiple times.
 308         std::set<Effect *> completed_effects;
 309
 310         // Effects in the current phase, as well as inputs (outputs from other phases
 311         // that we depend on). Note that since we start iterating from the end,
 312         // the effect list will be in the reverse order.
 313         std::vector<Effect *> this_phase_inputs;
 314         std::vector<Effect *> this_phase_effects;
 315
 316         // Effects that we have yet to calculate, but that we know should
 317         // be in the current phase.
 318         std::stack<Effect *> effects_todo_this_phase;
 319
 320         // Effects that we have yet to calculate, but that come from other phases.
 321         // We delay these until we have this phase done in its entirety,
 322         // at which point we pick any of them and start a new phase from that.
 323         std::stack<Effect *> effects_todo_other_phases;
 324
 325         effects_todo_this_phase.push(output);
 326
 327         for ( ;; ) {  // Termination condition within loop.
 328                 if (!effects_todo_this_phase.empty()) {
 329                         // OK, we have more to do this phase.
 330                         Effect *effect = effects_todo_this_phase.top();
 331                         effects_todo_this_phase.pop();
 332
 333                         // This should currently only happen for effects that are phase outputs,
 334                         // and we throw those out separately below.
 335                         assert(completed_effects.count(effect) == 0);
 336
 337                         this_phase_effects.push_back(effect);
 338                         completed_effects.insert(effect);
 339
 340                         // Find all the dependencies of this effect, and add them to the stack.
 341                         assert(incoming_links.count(effect) == 1);
 342                         std::vector<Effect *> deps = incoming_links[effect];
 343                         assert(effect->num_inputs() == deps.size());
 344                         for (unsigned i = 0; i < deps.size(); ++i) {
 345                                 bool start_new_phase = false;
 346
 347                                 // FIXME: If we sample directly from a texture, we won't need this.
 348                                 if (effect->needs_texture_bounce()) {
 349                                         start_new_phase = true;
 350                                 }
 351
 352                                 assert(outgoing_links.count(deps[i]) == 1);
 353                                 if (outgoing_links[deps[i]].size() > 1 && deps[i]->num_inputs() > 0) {
 354                                         // More than one effect uses this as the input,
 355                                         // and it is not a texture itself.
 356                                         // The easiest thing to do (and probably also the safest
 357                                         // performance-wise in most cases) is to bounce it to a texture
 358                                         // and then let the next passes read from that.
 359                                         start_new_phase = true;
 360                                 }
 361
 362                                 if (deps[i]->changes_output_size()) {
 363                                         start_new_phase = true;
 364                                 }
 365
 366                                 if (start_new_phase) {
 367                                         effects_todo_other_phases.push(deps[i]);
 368                                         this_phase_inputs.push_back(deps[i]);
 369                                 } else {
 370                                         effects_todo_this_phase.push(deps[i]);
 371                                 }
 372                         }
 373                         continue;
 374                 }
 375
 376                 // No more effects to do this phase. Take all the ones we have,
 377                 // and create a GLSL program for it.
 378                 if (!this_phase_effects.empty()) {
 379                         reverse(this_phase_effects.begin(), this_phase_effects.end());
 380                         phases.push_back(compile_glsl_program(this_phase_inputs, this_phase_effects));
 381                         output_effects_to_phase.insert(std::make_pair(this_phase_effects.back(), phases.back()));
 382                         this_phase_inputs.clear();
 383                         this_phase_effects.clear();
 384                 }
 385                 assert(this_phase_inputs.empty());
 386                 assert(this_phase_effects.empty());
 387
 388                 // If we have no effects left, exit.
 389                 if (effects_todo_other_phases.empty()) {
 390                         break;
 391                 }
 392
 393                 Effect *effect = effects_todo_other_phases.top();
 394                 effects_todo_other_phases.pop();
 395
 396                 if (completed_effects.count(effect) == 0) {
 397                         // Start a new phase, calculating from this effect.
 398                         effects_todo_this_phase.push(effect);
 399                 }
 400         }
 401
 402         // Finally, since the phases are found from the output but must be executed
 403         // from the input(s), reverse them, too.
 404         std::reverse(phases.begin(), phases.end());
 405 }
 406
 407 void EffectChain::find_output_size(EffectChain::Phase *phase)
 408 {
 409         Effect *output_effect = phase->effects.back();
 410
 411         // If the last effect explicitly sets an output size,
 412         // use that.
 413         if (output_effect->changes_output_size()) {
 414                 output_effect->get_output_size(&phase->output_width, &phase->output_height);
 415                 return;
 416         }
 417
 418         // If not, look at the input phases, if any. We select the largest one
 419         // (really assuming they all have the same aspect currently), by pixel count.
 420         if (!phase->inputs.empty()) {
 421                 unsigned best_width = 0, best_height = 0;
 422                 for (unsigned i = 0; i < phase->inputs.size(); ++i) {
 423                         Effect *input = phase->inputs[i];
 424                         assert(output_effects_to_phase.count(input) != 0);
 425                         const Phase *input_phase = output_effects_to_phase[input];
 426                         assert(input_phase->output_width != 0);
 427                         assert(input_phase->output_height != 0);
 428                         if (input_phase->output_width * input_phase->output_height > best_width * best_height) {
 429                                 best_width = input_phase->output_width;
 430                                 best_height = input_phase->output_height;
 431                         }
 432                 }
 433                 assert(best_width != 0);
 434                 assert(best_height != 0);
 435                 phase->output_width = best_width;
 436                 phase->output_height = best_height;
 437                 return;
 438         }
 439
 440         // OK, no inputs. Just use the global width/height.
 441         // TODO: We probably want to use the texture's size eventually.
 442         phase->output_width = width;
 443         phase->output_height = height;
 444 }
 445
 446 void EffectChain::finalize()
 447 {
 448         // Find the output effect. This is, simply, one that has no outgoing links.
 449         // If there are multiple ones, the graph is malformed (we do not support
 450         // multiple outputs right now).
 451         std::vector<Effect *> output_effects;
 452         for (unsigned i = 0; i < effects.size(); ++i) {
 453                 Effect *effect = effects[i];
 454                 if (outgoing_links.count(effect) == 0 || outgoing_links[effect].size() == 0) {
 455                         output_effects.push_back(effect);
 456                 }
 457         }
 458         assert(output_effects.size() == 1);
 459         Effect *output_effect = output_effects[0];
 460
 461         // Add normalizers to get the output format right.
 462         assert(output_gamma_curve.count(output_effect) != 0);
 463         assert(output_color_space.count(output_effect) != 0);
 464         ColorSpace current_color_space = output_color_space[output_effect];
 465         if (current_color_space != output_format.color_space) {
 466                 ColorSpaceConversionEffect *colorspace_conversion = new ColorSpaceConversionEffect();
 467                 colorspace_conversion->set_int("source_space", current_color_space);
 468                 colorspace_conversion->set_int("destination_space", output_format.color_space);
 469                 std::vector<Effect *> inputs;
 470                 inputs.push_back(output_effect);
 471                 colorspace_conversion->add_self_to_effect_chain(this, inputs);
 472                 output_color_space[colorspace_conversion] = output_format.color_space;
 473                 output_effect = colorspace_conversion;
 474         }
 475         GammaCurve current_gamma_curve = output_gamma_curve[output_effect];
 476         if (current_gamma_curve != output_format.gamma_curve) {
 477                 if (current_gamma_curve != GAMMA_LINEAR) {
 478                         output_effect = normalize_to_linear_gamma(output_effect);
 479                         current_gamma_curve = GAMMA_LINEAR;
 480                 }
 481                 GammaCompressionEffect *gamma_conversion = new GammaCompressionEffect();
 482                 gamma_conversion->set_int("destination_curve", output_format.gamma_curve);
 483                 std::vector<Effect *> inputs;
 484                 inputs.push_back(output_effect);
 485                 gamma_conversion->add_self_to_effect_chain(this, inputs);
 486                 output_gamma_curve[gamma_conversion] = output_format.gamma_curve;
 487                 output_effect = gamma_conversion;
 488         }
 489
 490         // Construct all needed GLSL programs, starting at the output.
 491         construct_glsl_programs(output_effect);
 492
 493         // If we have more than one phase, we need intermediate render-to-texture.
 494         // Construct an FBO, and then as many textures as we need.
 495         // We choose the simplest option of having one texture per output,
 496         // since otherwise this turns into an (albeit simple)
 497         // register allocation problem.
 498         if (phases.size() > 1) {
 499                 glGenFramebuffers(1, &fbo);
 500
 501                 for (unsigned i = 0; i < phases.size() - 1; ++i) {
 502                         find_output_size(phases[i]);
 503
 504                         Effect *output_effect = phases[i]->effects.back();
 505                         GLuint temp_texture;
 506                         glGenTextures(1, &temp_texture);
 507                         check_error();
 508                         glBindTexture(GL_TEXTURE_2D, temp_texture);
 509                         check_error();
 510                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 511                         check_error();
 512                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 513                         check_error();
 514                         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F_ARB, phases[i]->output_width, phases[i]->output_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 515                         check_error();
 516                         effect_output_textures.insert(std::make_pair(output_effect, temp_texture));
 517                         effect_output_texture_sizes.insert(std::make_pair(output_effect, std::make_pair(phases[i]->output_width, phases[i]->output_height)));
 518                 }
 519         }
 520
 521         for (unsigned i = 0; i < inputs.size(); ++i) {
 522                 inputs[i]->finalize();
 523         }
 524
 525         assert(phases[0]->inputs.empty());
 526
 527         finalized = true;
 528 }
 529
 530 void EffectChain::render_to_screen()
 531 {
 532         assert(finalized);
 533
 534         // Basic state.
 535         glDisable(GL_BLEND);
 536         check_error();
 537         glDisable(GL_DEPTH_TEST);
 538         check_error();
 539         glDepthMask(GL_FALSE);
 540         check_error();
 541
 542         glMatrixMode(GL_PROJECTION);
 543         glLoadIdentity();
 544         glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
 545
 546         glMatrixMode(GL_MODELVIEW);
 547         glLoadIdentity();
 548
 549         if (phases.size() > 1) {
 550                 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
 551                 check_error();
 552         }
 553
 554         std::set<Effect *> generated_mipmaps;
 555
 556         for (unsigned phase = 0; phase < phases.size(); ++phase) {
 557                 // See if the requested output size has changed. If so, we need to recreate
 558                 // the texture (and before we start setting up inputs).
 559                 if (phase != phases.size() - 1) {
 560                         find_output_size(phases[phase]);
 561
 562                         Effect *output_effect = phases[phase]->effects.back();
 563                         assert(effect_output_texture_sizes.count(output_effect) != 0);
 564                         std::pair<GLuint, GLuint> old_size = effect_output_texture_sizes[output_effect];
 565
 566                         if (old_size.first != phases[phase]->output_width ||
 567                             old_size.second != phases[phase]->output_height) {
 568                                 glActiveTexture(GL_TEXTURE0);
 569                                 check_error();
 570                                 assert(effect_output_textures.count(output_effect) != 0);
 571                                 glBindTexture(GL_TEXTURE_2D, effect_output_textures[output_effect]);
 572                                 check_error();
 573                                 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F_ARB, phases[phase]->output_width, phases[phase]->output_height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 574                                 check_error();
 575                                 effect_output_texture_sizes[output_effect] = std::make_pair(phases[phase]->output_width, phases[phase]->output_height);
 576                                 glBindTexture(GL_TEXTURE_2D, 0);
 577                                 check_error();
 578                         }
 579                 }
 580
 581                 glUseProgram(phases[phase]->glsl_program_num);
 582                 check_error();
 583
 584                 // Set up RTT inputs for this phase.
 585                 for (unsigned sampler = 0; sampler < phases[phase]->inputs.size(); ++sampler) {
 586                         glActiveTexture(GL_TEXTURE0 + sampler);
 587                         Effect *input = phases[phase]->inputs[sampler];
 588                         assert(effect_output_textures.count(input) != 0);
 589                         glBindTexture(GL_TEXTURE_2D, effect_output_textures[input]);
 590                         check_error();
 591                         if (phases[phase]->input_needs_mipmaps) {
 592                                 if (generated_mipmaps.count(input) == 0) {
 593                                         glGenerateMipmap(GL_TEXTURE_2D);
 594                                         check_error();
 595                                         generated_mipmaps.insert(input);
 596                                 }
 597                                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
 598                                 check_error();
 599                         } else {
 600                                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 601                                 check_error();
 602                         }
 603
 604                         assert(effect_ids.count(input));
 605                         std::string texture_name = std::string("tex_") + effect_ids[input];
 606                         glUniform1i(glGetUniformLocation(phases[phase]->glsl_program_num, texture_name.c_str()), sampler);
 607                         check_error();
 608                 }
 609
 610                 // And now the output.
 611                 if (phase == phases.size() - 1) {
 612                         // Last phase goes directly to the screen.
 613                         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 614                         check_error();
 615                         glViewport(0, 0, width, height);
 616                 } else {
 617                         Effect *output_effect = phases[phase]->effects.back();
 618                         assert(effect_output_textures.count(output_effect) != 0);
 619                         glFramebufferTexture2D(
 620                                 GL_FRAMEBUFFER,
 621                                 GL_COLOR_ATTACHMENT0,
 622                                 GL_TEXTURE_2D,
 623                                 effect_output_textures[output_effect],
 624                                 0);
 625                         check_error();
 626                         glViewport(0, 0, phases[phase]->output_width, phases[phase]->output_height);
 627                 }
 628
 629                 // Give the required parameters to all the effects.
 630                 unsigned sampler_num = phases[phase]->inputs.size();
 631                 for (unsigned i = 0; i < phases[phase]->effects.size(); ++i) {
 632                         Effect *effect = phases[phase]->effects[i];
 633                         effect->set_gl_state(phases[phase]->glsl_program_num, effect_ids[effect], &sampler_num);
 634                         check_error();
 635                 }
 636
 637                 // Now draw!
 638                 glBegin(GL_QUADS);
 639
 640                 glTexCoord2f(0.0f, 0.0f);
 641                 glVertex2f(0.0f, 0.0f);
 642
 643                 glTexCoord2f(1.0f, 0.0f);
 644                 glVertex2f(1.0f, 0.0f);
 645
 646                 glTexCoord2f(1.0f, 1.0f);
 647                 glVertex2f(1.0f, 1.0f);
 648
 649                 glTexCoord2f(0.0f, 1.0f);
 650                 glVertex2f(0.0f, 1.0f);
 651
 652                 glEnd();
 653                 check_error();
 654
 655                 for (unsigned i = 0; i < phases[phase]->effects.size(); ++i) {
 656                         Effect *effect = phases[phase]->effects[i];
 657                         effect->clear_gl_state();
 658                 }
 659         }
 660 }