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
  13 #include "util.h"
  14 #include "effect_chain.h"
  15 #include "gamma_expansion_effect.h"
  16 #include "gamma_compression_effect.h"
  17 #include "lift_gamma_gain_effect.h"
  18 #include "colorspace_conversion_effect.h"
  19 #include "sandbox_effect.h"
  20 #include "saturation_effect.h"
  21 #include "mirror_effect.h"
  22 #include "vignette_effect.h"
  23 #include "blur_effect.h"
  24 #include "diffusion_effect.h"
  25
  26 EffectChain::EffectChain(unsigned width, unsigned height)
  27         : width(width),
  28           height(height),
  29           use_srgb_texture_format(false),
  30           finalized(false) {}
  31
  32 void EffectChain::add_input(const ImageFormat &format)
  33 {
  34         input_format = format;
  35         output_color_space.insert(std::make_pair(static_cast<Effect *>(NULL), format.color_space));
  36         output_gamma_curve.insert(std::make_pair(static_cast<Effect *>(NULL), format.gamma_curve));
  37         effect_ids.insert(std::make_pair(static_cast<Effect *>(NULL), "src_image"));
  38 }
  39
  40 void EffectChain::add_output(const ImageFormat &format)
  41 {
  42         output_format = format;
  43 }
  44
  45 void EffectChain::add_effect_raw(Effect *effect, const std::vector<Effect *> &inputs)
  46 {
  47         char effect_id[256];
  48         sprintf(effect_id, "eff%u", (unsigned)effects.size());
  49
  50         effects.push_back(effect);
  51         effect_ids.insert(std::make_pair(effect, effect_id));
  52         assert(inputs.size() == effect->num_inputs());
  53         for (unsigned i = 0; i < inputs.size(); ++i) {
  54                 if (inputs[i] != NULL) {
  55                         assert(std::find(effects.begin(), effects.end(), inputs[i]) != effects.end());
  56                 }
  57                 outgoing_links[inputs[i]].push_back(effect);
  58         }
  59         incoming_links.insert(std::make_pair(effect, inputs));
  60         output_gamma_curve[effect] = output_gamma_curve[last_added_effect()];
  61         output_color_space[effect] = output_color_space[last_added_effect()];
  62 }
  63
  64 Effect *instantiate_effect(EffectId effect)
  65 {
  66         switch (effect) {
  67         case EFFECT_GAMMA_EXPANSION:
  68                 return new GammaExpansionEffect();
  69         case EFFECT_GAMMA_COMPRESSION:
  70                 return new GammaCompressionEffect();
  71         case EFFECT_COLOR_SPACE_CONVERSION:
  72                 return new ColorSpaceConversionEffect();
  73         case EFFECT_SANDBOX:
  74                 return new SandboxEffect();
  75         case EFFECT_LIFT_GAMMA_GAIN:
  76                 return new LiftGammaGainEffect();
  77         case EFFECT_SATURATION:
  78                 return new SaturationEffect();
  79         case EFFECT_MIRROR:
  80                 return new MirrorEffect();
  81         case EFFECT_VIGNETTE:
  82                 return new VignetteEffect();
  83         case EFFECT_BLUR:
  84                 return new BlurEffect();
  85         case EFFECT_DIFFUSION:
  86                 return new DiffusionEffect();
  87         }
  88         assert(false);
  89 }
  90
  91 Effect *EffectChain::normalize_to_linear_gamma(Effect *input)
  92 {
  93         assert(output_gamma_curve.count(input) != 0);
  94         if (output_gamma_curve[input] == GAMMA_sRGB) {
  95                 // TODO: check if the extension exists
  96                 use_srgb_texture_format = true;
  97                 output_gamma_curve[input] = GAMMA_LINEAR;
  98                 return input;
  99         } else {
 100                 GammaExpansionEffect *gamma_conversion = new GammaExpansionEffect();
 101                 gamma_conversion->set_int("source_curve", output_gamma_curve[input]);
 102                 std::vector<Effect *> inputs;
 103                 inputs.push_back(input);
 104                 gamma_conversion->add_self_to_effect_chain(this, inputs);
 105                 output_gamma_curve[gamma_conversion] = GAMMA_LINEAR;
 106                 return gamma_conversion;
 107         }
 108 }
 109
 110 Effect *EffectChain::normalize_to_srgb(Effect *input)
 111 {
 112         assert(output_gamma_curve.count(input) != 0);
 113         assert(output_color_space.count(input) != 0);
 114         assert(output_gamma_curve[input] == GAMMA_LINEAR);
 115         ColorSpaceConversionEffect *colorspace_conversion = new ColorSpaceConversionEffect();
 116         colorspace_conversion->set_int("source_space", output_color_space[input]);
 117         colorspace_conversion->set_int("destination_space", COLORSPACE_sRGB);
 118         std::vector<Effect *> inputs;
 119         inputs.push_back(input);
 120         colorspace_conversion->add_self_to_effect_chain(this, inputs);
 121         output_color_space[colorspace_conversion] = COLORSPACE_sRGB;
 122         return colorspace_conversion;
 123 }
 124
 125 Effect *EffectChain::add_effect(EffectId effect_id, const std::vector<Effect *> &inputs)
 126 {
 127         Effect *effect = instantiate_effect(effect_id);
 128
 129         assert(inputs.size() == effect->num_inputs());
 130
 131         std::vector<Effect *> normalized_inputs = inputs;
 132         for (unsigned i = 0; i < normalized_inputs.size(); ++i) {
 133                 assert(output_gamma_curve.count(normalized_inputs[i]) != 0);
 134                 if (effect->needs_linear_light() && output_gamma_curve[normalized_inputs[i]] != GAMMA_LINEAR) {
 135                         normalized_inputs[i] = normalize_to_linear_gamma(normalized_inputs[i]);
 136                 }
 137                 assert(output_color_space.count(normalized_inputs[i]) != 0);
 138                 if (effect->needs_srgb_primaries() && output_color_space[normalized_inputs[i]] != COLORSPACE_sRGB) {
 139                         normalized_inputs[i] = normalize_to_srgb(normalized_inputs[i]);
 140                 }
 141         }
 142
 143         effect->add_self_to_effect_chain(this, normalized_inputs);
 144         return effect;
 145 }
 146
 147 // GLSL pre-1.30 doesn't support token pasting. Replace PREFIX(x) with <effect_id>_x.
 148 std::string replace_prefix(const std::string &text, const std::string &prefix)
 149 {
 150         std::string output;
 151         size_t start = 0;
 152
 153         while (start < text.size()) {
 154                 size_t pos = text.find("PREFIX(", start);
 155                 if (pos == std::string::npos) {
 156                         output.append(text.substr(start, std::string::npos));
 157                         break;
 158                 }
 159
 160                 output.append(text.substr(start, pos - start));
 161                 output.append(prefix);
 162                 output.append("_");
 163
 164                 pos += strlen("PREFIX(");
 165
 166                 // Output stuff until we find the matching ), which we then eat.
 167                 int depth = 1;
 168                 size_t end_arg_pos = pos;
 169                 while (end_arg_pos < text.size()) {
 170                         if (text[end_arg_pos] == '(') {
 171                                 ++depth;
 172                         } else if (text[end_arg_pos] == ')') {
 173                                 --depth;
 174                                 if (depth == 0) {
 175                                         break;
 176                                 }
 177                         }
 178                         ++end_arg_pos;
 179                 }
 180                 output.append(text.substr(pos, end_arg_pos - pos));
 181                 ++end_arg_pos;
 182                 assert(depth == 0);
 183                 start = end_arg_pos;
 184         }
 185         return output;
 186 }
 187
 188 EffectChain::Phase EffectChain::compile_glsl_program(const std::vector<Effect *> &inputs, const std::vector<Effect *> &effects)
 189 {
 190         assert(!inputs.empty());
 191         assert(!effects.empty());
 192
 193         // Figure out the true set of inputs to this phase. These are the ones
 194         // that we need somehow but don't calculate ourselves.
 195         std::set<Effect *> effect_set(effects.begin(), effects.end());
 196         std::set<Effect *> input_set(inputs.begin(), inputs.end());
 197         std::vector<Effect *> true_inputs;
 198         std::set_difference(input_set.begin(), input_set.end(),
 199                 effect_set.begin(), effect_set.end(),
 200                 std::back_inserter(true_inputs));
 201
 202         bool input_needs_mipmaps = false;
 203         std::string frag_shader = read_file("header.frag");
 204
 205         // Create functions for all the texture inputs that we need.
 206         for (unsigned i = 0; i < true_inputs.size(); ++i) {
 207                 Effect *effect = true_inputs[i];
 208                 assert(effect_ids.count(effect) != 0);
 209                 std::string effect_id = effect_ids[effect];
 210
 211                 frag_shader += std::string("uniform sampler2D tex_") + effect_id + ";\n";
 212                 frag_shader += std::string("vec4 ") + effect_id + "(vec2 tc) {\n";
 213                 if (effect == NULL) {
 214                         // OpenGL's origin is bottom-left, but most graphics software assumes
 215                         // a top-left origin. Thus, for inputs that come from the user,
 216                         // we flip the y coordinate. However, for FBOs, the origin
 217                         // is all correct, so don't do anything.
 218                         frag_shader += "\ttc.y = 1.0f - tc.y;\n";
 219                 }
 220                 frag_shader += "\treturn texture2D(tex_" + effect_id + ", tc);\n";
 221                 frag_shader += "}\n";
 222                 frag_shader += "\n";
 223         }
 224
 225         std::string last_effect_id;
 226         for (unsigned i = 0; i < effects.size(); ++i) {
 227                 Effect *effect = effects[i];
 228                 assert(effect != NULL);
 229                 assert(effect_ids.count(effect) != 0);
 230                 std::string effect_id = effect_ids[effect];
 231                 last_effect_id = effect_id;
 232
 233                 if (incoming_links[effect].size() == 1) {
 234                         frag_shader += std::string("#define INPUT ") + effect_ids[incoming_links[effect][0]] + "\n";
 235                 } else {
 236                         for (unsigned j = 0; j < incoming_links[effect].size(); ++j) {
 237                                 char buf[256];
 238                                 sprintf(buf, "#define INPUT%d %s\n", j + 1, effect_ids[incoming_links[effect][j]].c_str());
 239                                 frag_shader += buf;
 240                         }
 241                 }
 242
 243                 frag_shader += "\n";
 244                 frag_shader += std::string("#define FUNCNAME ") + effect_id + "\n";
 245                 frag_shader += replace_prefix(effect->output_convenience_uniforms(), effect_id);
 246                 frag_shader += replace_prefix(effect->output_fragment_shader(), effect_id);
 247                 frag_shader += "#undef PREFIX\n";
 248                 frag_shader += "#undef FUNCNAME\n";
 249                 if (incoming_links[effect].size() == 1) {
 250                         frag_shader += "#undef INPUT\n";
 251                 } else {
 252                         for (unsigned j = 0; j < incoming_links[effect].size(); ++j) {
 253                                 char buf[256];
 254                                 sprintf(buf, "#undef INPUT%d\n", j + 1);
 255                                 frag_shader += buf;
 256                         }
 257                 }
 258                 frag_shader += "\n";
 259
 260                 input_needs_mipmaps |= effect->needs_mipmaps();
 261         }
 262         assert(!last_effect_id.empty());
 263         frag_shader += std::string("#define INPUT ") + last_effect_id + "\n";
 264         frag_shader.append(read_file("footer.frag"));
 265         printf("%s\n", frag_shader.c_str());
 266
 267         GLuint glsl_program_num = glCreateProgram();
 268         GLuint vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 269         GLuint fs_obj = compile_shader(frag_shader, GL_FRAGMENT_SHADER);
 270         glAttachShader(glsl_program_num, vs_obj);
 271         check_error();
 272         glAttachShader(glsl_program_num, fs_obj);
 273         check_error();
 274         glLinkProgram(glsl_program_num);
 275         check_error();
 276
 277         Phase phase;
 278         phase.glsl_program_num = glsl_program_num;
 279         phase.input_needs_mipmaps = input_needs_mipmaps;
 280         phase.inputs = true_inputs;
 281         phase.effects = effects;
 282
 283         return phase;
 284 }
 285
 286 // Construct GLSL programs, starting at the given effect and following
 287 // the chain from there. We end a program every time we come to an effect
 288 // marked as "needs texture bounce", one that is used by multiple other
 289 // effects, and of course at the end.
 290 void EffectChain::construct_glsl_programs(Effect *start, std::set<Effect *> *completed_effects)
 291 {
 292         if (completed_effects->count(start) != 0) {
 293                 // This has already been done for us.
 294                 return;
 295         }
 296
 297         std::vector<Effect *> this_phase_inputs;  // Also includes all intermediates; these will be filtered away later.
 298         std::vector<Effect *> this_phase_effects;
 299         Effect *node = start;
 300         for ( ;; ) {  // Termination condition within loop.
 301                 if (node == NULL) {
 302                         this_phase_inputs.push_back(node);
 303                 } else {
 304                         // Check that we have all the inputs we need for this effect.
 305                         // If not, we end the phase here right away; the other side
 306                         // of the input chain will eventually come and pick the effect up.
 307                         assert(incoming_links.count(node) != 0);
 308                         std::vector<Effect *> deps = incoming_links[node];
 309                         assert(!deps.empty());
 310                         bool have_all_deps = true;
 311                         for (unsigned i = 0; i < deps.size(); ++i) {
 312                                 if (completed_effects->count(deps[i]) == 0) {
 313                                         have_all_deps = false;
 314                                         break;
 315                                 }
 316                         }
 317
 318                         if (!have_all_deps) {
 319                                 if (!this_phase_effects.empty()) {
 320                                         phases.push_back(compile_glsl_program(this_phase_inputs, this_phase_effects));
 321                                 }
 322                                 return;
 323                         }
 324                         this_phase_inputs.insert(this_phase_inputs.end(), deps.begin(), deps.end());
 325                         this_phase_effects.push_back(node);
 326                 }
 327                 completed_effects->insert(node);
 328
 329                 // Find all the effects that use this one as a direct input.
 330                 if (outgoing_links.count(node) == 0) {
 331                         // End of the line; output.
 332                         phases.push_back(compile_glsl_program(this_phase_inputs, this_phase_effects));
 333                         return;
 334                 }
 335
 336                 std::vector<Effect *> next = outgoing_links[node];
 337                 assert(!next.empty());
 338                 if (next.size() > 1) {
 339                         // More than one effect uses this as the input.
 340                         // The easiest thing to do (and probably also the safest
 341                         // performance-wise in most cases) is to bounce it to a texture
 342                         // and then let the next passes read from that.
 343                         if (node != NULL) {
 344                                 phases.push_back(compile_glsl_program(this_phase_inputs, this_phase_effects));
 345                         }
 346
 347                         // Start phases for all the effects that need us (in arbitrary order).
 348                         for (unsigned i = 0; i < next.size(); ++i) {
 349                                 construct_glsl_programs(next[i], completed_effects);
 350                         }
 351                         return;
 352                 }
 353
 354                 // OK, only one effect uses this as the input. Keep iterating,
 355                 // but first see if it requires a texture bounce; if so, give it
 356                 // one by starting a new phase.
 357                 node = next[0];
 358                 if (node->needs_texture_bounce()) {
 359                         phases.push_back(compile_glsl_program(this_phase_inputs, this_phase_effects));
 360                         this_phase_inputs.clear();
 361                         this_phase_effects.clear();
 362                 }
 363         }
 364 }
 365
 366 void EffectChain::finalize()
 367 {
 368         // Add normalizers to get the output format right.
 369         assert(output_gamma_curve.count(last_added_effect()) != 0);
 370         assert(output_color_space.count(last_added_effect()) != 0);
 371         ColorSpace current_color_space = output_color_space[last_added_effect()];  // FIXME
 372         if (current_color_space != output_format.color_space) {
 373                 ColorSpaceConversionEffect *colorspace_conversion = new ColorSpaceConversionEffect();
 374                 colorspace_conversion->set_int("source_space", current_color_space);
 375                 colorspace_conversion->set_int("destination_space", output_format.color_space);
 376                 std::vector<Effect *> inputs;
 377                 inputs.push_back(last_added_effect());
 378                 colorspace_conversion->add_self_to_effect_chain(this, inputs);
 379                 output_color_space[colorspace_conversion] = output_format.color_space;
 380         }
 381         GammaCurve current_gamma_curve = output_gamma_curve[last_added_effect()];  // FIXME
 382         if (current_gamma_curve != output_format.gamma_curve) {
 383                 if (current_gamma_curve != GAMMA_LINEAR) {
 384                         normalize_to_linear_gamma(last_added_effect());  // FIXME
 385                 }
 386                 assert(current_gamma_curve == GAMMA_LINEAR);
 387                 GammaCompressionEffect *gamma_conversion = new GammaCompressionEffect();
 388                 gamma_conversion->set_int("destination_curve", output_format.gamma_curve);
 389                 std::vector<Effect *> inputs;
 390                 inputs.push_back(last_added_effect());
 391                 gamma_conversion->add_self_to_effect_chain(this, inputs);
 392                 output_gamma_curve[gamma_conversion] = output_format.gamma_curve;
 393         }
 394
 395         // Construct all needed GLSL programs, starting at the input.
 396         std::set<Effect *> completed_effects;
 397         construct_glsl_programs(NULL, &completed_effects);
 398
 399         // If we have more than one phase, we need intermediate render-to-texture.
 400         // Construct an FBO, and then as many textures as we need.
 401         // We choose the simplest option of having one texture per output,
 402         // since otherwise this turns into an (albeit simple)
 403         // register allocation problem.
 404         if (phases.size() > 1) {
 405                 glGenFramebuffers(1, &fbo);
 406
 407                 for (unsigned i = 0; i < phases.size() - 1; ++i) {
 408                         Effect *output_effect = phases[i].effects.back();
 409                         GLuint temp_texture;
 410                         glGenTextures(1, &temp_texture);
 411                         check_error();
 412                         glBindTexture(GL_TEXTURE_2D, temp_texture);
 413                         check_error();
 414                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 415                         check_error();
 416                         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 417                         check_error();
 418                         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA16F_ARB, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, NULL);
 419                         check_error();
 420                         effect_output_textures.insert(std::make_pair(output_effect, temp_texture));
 421                 }
 422         }
 423
 424         // Translate the input format to OpenGL's enums.
 425         GLenum internal_format;
 426         if (use_srgb_texture_format) {
 427                 internal_format = GL_SRGB8;
 428         } else {
 429                 internal_format = GL_RGBA8;
 430         }
 431         if (input_format.pixel_format == FORMAT_RGB) {
 432                 format = GL_RGB;
 433                 bytes_per_pixel = 3;
 434         } else if (input_format.pixel_format == FORMAT_RGBA) {
 435                 format = GL_RGBA;
 436                 bytes_per_pixel = 4;
 437         } else if (input_format.pixel_format == FORMAT_BGR) {
 438                 format = GL_BGR;
 439                 bytes_per_pixel = 3;
 440         } else if (input_format.pixel_format == FORMAT_BGRA) {
 441                 format = GL_BGRA;
 442                 bytes_per_pixel = 4;
 443         } else {
 444                 assert(false);
 445         }
 446
 447         // Create PBO to hold the texture holding the input image, and then the texture itself.
 448         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 2);
 449         check_error();
 450         glBufferData(GL_PIXEL_UNPACK_BUFFER_ARB, width * height * bytes_per_pixel, NULL, GL_STREAM_DRAW);
 451         check_error();
 452         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
 453         check_error();
 454
 455         glGenTextures(1, &source_image_num);
 456         check_error();
 457         glBindTexture(GL_TEXTURE_2D, source_image_num);
 458         check_error();
 459         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 460         check_error();
 461         // Intel/Mesa seems to have a broken glGenerateMipmap() for non-FBO textures, so do it here.
 462         glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP, phases[0].input_needs_mipmaps ? GL_TRUE : GL_FALSE);
 463         check_error();
 464         glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0, format, GL_UNSIGNED_BYTE, NULL);
 465         check_error();
 466
 467         finalized = true;
 468 }
 469
 470 void EffectChain::render_to_screen(unsigned char *src)
 471 {
 472         assert(finalized);
 473
 474         // Copy the pixel data into the PBO.
 475         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 2);
 476         check_error();
 477         void *mapped_pbo = glMapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB, GL_WRITE_ONLY);
 478         memcpy(mapped_pbo, src, width * height * bytes_per_pixel);
 479         glUnmapBufferARB(GL_PIXEL_UNPACK_BUFFER_ARB);
 480         check_error();
 481
 482         // Re-upload the texture from the PBO.
 483         glActiveTexture(GL_TEXTURE0);
 484         check_error();
 485         glBindTexture(GL_TEXTURE_2D, source_image_num);
 486         check_error();
 487         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height, format, GL_UNSIGNED_BYTE, BUFFER_OFFSET(0));
 488         check_error();
 489         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 490         check_error();
 491         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 492         check_error();
 493         glBindBuffer(GL_PIXEL_UNPACK_BUFFER_ARB, 0);
 494         check_error();
 495
 496         // Basic state.
 497         glDisable(GL_BLEND);
 498         check_error();
 499         glDisable(GL_DEPTH_TEST);
 500         check_error();
 501         glDepthMask(GL_FALSE);
 502         check_error();
 503
 504         glMatrixMode(GL_PROJECTION);
 505         glLoadIdentity();
 506         glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
 507
 508         glMatrixMode(GL_MODELVIEW);
 509         glLoadIdentity();
 510
 511         if (phases.size() > 1) {
 512                 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
 513                 check_error();
 514         }
 515
 516         std::set<Effect *> generated_mipmaps;
 517         generated_mipmaps.insert(NULL);  // Already done further up.
 518
 519         for (unsigned phase = 0; phase < phases.size(); ++phase) {
 520                 glUseProgram(phases[phase].glsl_program_num);
 521                 check_error();
 522
 523                 // Set up inputs for this phase.
 524                 assert(!phases[phase].inputs.empty());
 525                 for (unsigned sampler = 0; sampler < phases[phase].inputs.size(); ++sampler) {
 526                         glActiveTexture(GL_TEXTURE0 + sampler);
 527                         Effect *input = phases[phase].inputs[sampler];
 528                         if (input == NULL) {
 529                                 glBindTexture(GL_TEXTURE_2D, source_image_num);
 530                                 check_error();
 531                         } else {
 532                                 assert(effect_output_textures.count(input) != 0);
 533                                 glBindTexture(GL_TEXTURE_2D, effect_output_textures[input]);
 534                                 check_error();
 535                         }
 536                         if (phases[phase].input_needs_mipmaps) {
 537                                 if (generated_mipmaps.count(input) == 0) {
 538                                         glGenerateMipmap(GL_TEXTURE_2D);
 539                                         check_error();
 540                                         generated_mipmaps.insert(input);
 541                                 }
 542                                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
 543                                 check_error();
 544                         } else {
 545                                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 546                                 check_error();
 547                         }
 548
 549                         assert(effect_ids.count(input));
 550                         std::string texture_name = std::string("tex_") + effect_ids[input];
 551                         glUniform1i(glGetUniformLocation(phases[phase].glsl_program_num, texture_name.c_str()), sampler);
 552                         check_error();
 553                 }
 554
 555                 // And now the output.
 556                 if (phase == phases.size() - 1) {
 557                         // Last phase goes directly to the screen.
 558                         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 559                         check_error();
 560                 } else {
 561                         Effect *last_effect = phases[phase].effects.back();
 562                         assert(effect_output_textures.count(last_effect) != 0);
 563                         glFramebufferTexture2D(
 564                                 GL_FRAMEBUFFER,
 565                                 GL_COLOR_ATTACHMENT0,
 566                                 GL_TEXTURE_2D,
 567                                 effect_output_textures[last_effect],
 568                                 0);
 569                         check_error();
 570                 }
 571
 572                 // Give the required parameters to all the effects.
 573                 unsigned sampler_num = phases[phase].inputs.size();
 574                 for (unsigned i = 0; i < phases[phase].effects.size(); ++i) {
 575                         Effect *effect = phases[phase].effects[i];
 576                         effect->set_uniforms(phases[phase].glsl_program_num, effect_ids[effect], &sampler_num);
 577                 }
 578
 579                 // Now draw!
 580                 glBegin(GL_QUADS);
 581
 582                 glTexCoord2f(0.0f, 0.0f);
 583                 glVertex2f(0.0f, 0.0f);
 584
 585                 glTexCoord2f(1.0f, 0.0f);
 586                 glVertex2f(1.0f, 0.0f);
 587
 588                 glTexCoord2f(1.0f, 1.0f);
 589                 glVertex2f(1.0f, 1.0f);
 590
 591                 glTexCoord2f(0.0f, 1.0f);
 592                 glVertex2f(0.0f, 1.0f);
 593
 594                 glEnd();
 595                 check_error();
 596
 597                 // HACK
 598                 glActiveTexture(GL_TEXTURE0);
 599                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
 600                 check_error();
 601                 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 1000);
 602                 check_error();
 603         }
 604 }