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