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

   1 #include <assert.h>
   2 #include <pthread.h>
   3 #include <stdio.h>
   4 #include <stdlib.h>
   5 #include <algorithm>
   6 #include <map>
   7 #include <string>
   8 #include <utility>
   9 #include <epoxy/gl.h>
  10
  11 #include "init.h"
  12 #include "resource_pool.h"
  13 #include "util.h"
  14
  15 using namespace std;
  16
  17 namespace movit {
  18
  19 ResourcePool::ResourcePool(size_t program_freelist_max_length,
  20                            size_t texture_freelist_max_bytes,
  21                            size_t fbo_freelist_max_length)
  22         : program_freelist_max_length(program_freelist_max_length),
  23           texture_freelist_max_bytes(texture_freelist_max_bytes),
  24           fbo_freelist_max_length(fbo_freelist_max_length),
  25           texture_freelist_bytes(0)
  26 {
  27         pthread_mutex_init(&lock, NULL);
  28 }
  29
  30 ResourcePool::~ResourcePool()
  31 {
  32         assert(program_refcount.empty());
  33
  34         for (list<GLuint>::const_iterator freelist_it = program_freelist.begin();
  35              freelist_it != program_freelist.end();
  36              ++freelist_it) {
  37                 delete_program(*freelist_it);
  38         }
  39         assert(programs.empty());
  40         assert(program_shaders.empty());
  41
  42         for (list<GLuint>::const_iterator freelist_it = texture_freelist.begin();
  43              freelist_it != texture_freelist.end();
  44              ++freelist_it) {
  45                 GLuint free_texture_num = *freelist_it;
  46                 assert(texture_formats.count(free_texture_num) != 0);
  47                 texture_freelist_bytes -= estimate_texture_size(texture_formats[free_texture_num]);
  48                 texture_formats.erase(free_texture_num);
  49                 glDeleteTextures(1, &free_texture_num);
  50                 check_error();
  51         }
  52         assert(texture_formats.empty());
  53         assert(texture_freelist_bytes == 0);
  54
  55         void *context = get_gl_context_identifier();
  56         cleanup_unlinked_fbos(context);
  57
  58         for (map<void *, std::list<FBOFormatIterator> >::iterator context_it = fbo_freelist.begin();
  59              context_it != fbo_freelist.end();
  60              ++context_it) {
  61                 if (context_it->first != context) {
  62                         // If this does not hold, the client should have called clean_context() earlier.
  63                         assert(context_it->second.empty());
  64                         continue;
  65                 }
  66                 for (list<FBOFormatIterator>::const_iterator freelist_it = context_it->second.begin();
  67                      freelist_it != context_it->second.end();
  68                      ++freelist_it) {
  69                         FBOFormatIterator fbo_it = *freelist_it;
  70                         glDeleteFramebuffers(1, &fbo_it->second.fbo_num);
  71                         check_error();
  72                         fbo_formats.erase(fbo_it);
  73                 }
  74         }
  75
  76         assert(fbo_formats.empty());
  77 }
  78
  79 void ResourcePool::delete_program(GLuint glsl_program_num)
  80 {
  81         bool found_program = false;
  82         for (map<pair<string, string>, GLuint>::iterator program_it = programs.begin();
  83              program_it != programs.end();
  84              ++program_it) {
  85                 if (program_it->second == glsl_program_num) {
  86                         programs.erase(program_it);
  87                         found_program = true;
  88                         break;
  89                 }
  90         }
  91         assert(found_program);
  92
  93         map<GLuint, stack<GLuint> >::iterator instance_list_it = program_instances.find(glsl_program_num);
  94         assert(instance_list_it != program_instances.end());
  95
  96         while (!instance_list_it->second.empty()) {
  97                 GLuint instance_program_num = instance_list_it->second.top();
  98                 instance_list_it->second.pop();
  99                 glDeleteProgram(instance_program_num);
 100                 program_masters.erase(instance_program_num);
 101         }
 102         program_instances.erase(instance_list_it);
 103
 104         map<GLuint, ShaderSpec>::iterator shader_it =
 105                 program_shaders.find(glsl_program_num);
 106         assert(shader_it != program_shaders.end());
 107
 108         glDeleteShader(shader_it->second.vs_obj);
 109         glDeleteShader(shader_it->second.fs_obj);
 110         program_shaders.erase(shader_it);
 111 }
 112
 113 GLuint ResourcePool::compile_glsl_program(const string& vertex_shader,
 114                                           const string& fragment_shader,
 115                                           const vector<string>& fragment_shader_outputs)
 116 {
 117         GLuint glsl_program_num;
 118         pthread_mutex_lock(&lock);
 119
 120         // Augment the fragment shader program text with the outputs, so that they become
 121         // part of the key. Also potentially useful for debugging.
 122         string fragment_shader_processed = fragment_shader;
 123         for (unsigned output_index = 0; output_index < fragment_shader_outputs.size(); ++output_index) {
 124                 char buf[256];
 125                 snprintf(buf, sizeof(buf), "// Bound output: %s\n", fragment_shader_outputs[output_index].c_str());
 126                 fragment_shader_processed += buf;
 127         }
 128
 129         const pair<string, string> key(vertex_shader, fragment_shader_processed);
 130         if (programs.count(key)) {
 131                 // Already in the cache. Increment the refcount, or take it off the freelist
 132                 // if it's zero.
 133                 glsl_program_num = programs[key];
 134                 map<GLuint, int>::iterator refcount_it = program_refcount.find(glsl_program_num);
 135                 if (refcount_it != program_refcount.end()) {
 136                         ++refcount_it->second;
 137                 } else {
 138                         list<GLuint>::iterator freelist_it =
 139                                 find(program_freelist.begin(), program_freelist.end(), glsl_program_num);
 140                         assert(freelist_it != program_freelist.end());
 141                         program_freelist.erase(freelist_it);
 142                         program_refcount.insert(make_pair(glsl_program_num, 1));
 143                 }
 144         } else {
 145                 // Not in the cache. Compile the shaders.
 146                 GLuint vs_obj = compile_shader(vertex_shader, GL_VERTEX_SHADER);
 147                 check_error();
 148                 GLuint fs_obj = compile_shader(fragment_shader_processed, GL_FRAGMENT_SHADER);
 149                 check_error();
 150                 glsl_program_num = link_program(vs_obj, fs_obj, fragment_shader_outputs);
 151
 152                 if (movit_debug_level == MOVIT_DEBUG_ON) {
 153                         // Output shader to a temporary file, for easier debugging.
 154                         static int compiled_shader_num = 0;
 155                         char filename[256];
 156                         sprintf(filename, "chain-%03d.frag", compiled_shader_num++);
 157                         FILE *fp = fopen(filename, "w");
 158                         if (fp == NULL) {
 159                                 perror(filename);
 160                                 exit(1);
 161                         }
 162                         fprintf(fp, "%s\n", fragment_shader_processed.c_str());
 163                         fclose(fp);
 164                 }
 165
 166                 programs.insert(make_pair(key, glsl_program_num));
 167                 program_refcount.insert(make_pair(glsl_program_num, 1));
 168                 ShaderSpec spec;
 169                 spec.vs_obj = vs_obj;
 170                 spec.fs_obj = fs_obj;
 171                 spec.fragment_shader_outputs = fragment_shader_outputs;
 172                 program_shaders.insert(make_pair(glsl_program_num, spec));
 173                 stack<GLuint> instances;
 174                 instances.push(glsl_program_num);
 175                 program_instances.insert(make_pair(glsl_program_num, instances));
 176                 program_masters.insert(make_pair(glsl_program_num, glsl_program_num));
 177         }
 178         pthread_mutex_unlock(&lock);
 179         return glsl_program_num;
 180 }
 181
 182 GLuint ResourcePool::link_program(GLuint vs_obj,
 183                                   GLuint fs_obj,
 184                                   const vector<string>& fragment_shader_outputs)
 185 {
 186         GLuint glsl_program_num = glCreateProgram();
 187         check_error();
 188         glAttachShader(glsl_program_num, vs_obj);
 189         check_error();
 190         glAttachShader(glsl_program_num, fs_obj);
 191         check_error();
 192
 193         // Bind the outputs, if we have multiple ones.
 194         if (fragment_shader_outputs.size() > 1) {
 195                 for (unsigned output_index = 0; output_index < fragment_shader_outputs.size(); ++output_index) {
 196                         glBindFragDataLocation(glsl_program_num, output_index,
 197                                                fragment_shader_outputs[output_index].c_str());
 198                 }
 199         }
 200
 201         glLinkProgram(glsl_program_num);
 202         check_error();
 203
 204         GLint success;
 205         glGetProgramiv(glsl_program_num, GL_LINK_STATUS, &success);
 206         if (success == GL_FALSE) {
 207                 GLchar error_log[1024] = {0};
 208                 glGetProgramInfoLog(glsl_program_num, 1024, NULL, error_log);
 209                 fprintf(stderr, "Error linking program: %s\n", error_log);
 210                 exit(1);
 211         }
 212
 213         return glsl_program_num;
 214 }
 215
 216 void ResourcePool::release_glsl_program(GLuint glsl_program_num)
 217 {
 218         pthread_mutex_lock(&lock);
 219         map<GLuint, int>::iterator refcount_it = program_refcount.find(glsl_program_num);
 220         assert(refcount_it != program_refcount.end());
 221
 222         if (--refcount_it->second == 0) {
 223                 program_refcount.erase(refcount_it);
 224                 assert(find(program_freelist.begin(), program_freelist.end(), glsl_program_num)
 225                         == program_freelist.end());
 226                 program_freelist.push_front(glsl_program_num);
 227                 if (program_freelist.size() > program_freelist_max_length) {
 228                         delete_program(program_freelist.back());
 229                         program_freelist.pop_back();
 230                 }
 231         }
 232
 233         pthread_mutex_unlock(&lock);
 234 }
 235
 236 GLuint ResourcePool::use_glsl_program(GLuint glsl_program_num)
 237 {
 238         pthread_mutex_lock(&lock);
 239         assert(program_instances.count(glsl_program_num));
 240         stack<GLuint> &instances = program_instances[glsl_program_num];
 241
 242         GLuint instance_program_num;
 243         if (!instances.empty()) {
 244                 // There's an unused instance of this program; just return it.
 245                 instance_program_num = instances.top();
 246                 instances.pop();
 247         } else {
 248                 // We need to clone this program. (unuse_glsl_program()
 249                 // will later put it onto the list.)
 250                 map<GLuint, ShaderSpec>::iterator shader_it =
 251                         program_shaders.find(glsl_program_num);
 252                 assert(shader_it != program_shaders.end());
 253
 254                 instance_program_num = link_program(
 255                         shader_it->second.vs_obj,
 256                         shader_it->second.fs_obj,
 257                         shader_it->second.fragment_shader_outputs);
 258                 program_masters.insert(make_pair(instance_program_num, glsl_program_num));
 259         }
 260         pthread_mutex_unlock(&lock);
 261
 262         glUseProgram(instance_program_num);
 263         return instance_program_num;
 264 }
 265
 266 void ResourcePool::unuse_glsl_program(GLuint instance_program_num)
 267 {
 268         pthread_mutex_lock(&lock);
 269
 270         map<GLuint, GLuint>::const_iterator master_it = program_masters.find(instance_program_num);
 271         assert(master_it != program_masters.end());
 272
 273         assert(program_instances.count(master_it->second));
 274         stack<GLuint> &instances = program_instances[master_it->second];
 275
 276         instances.push(instance_program_num);
 277
 278         pthread_mutex_unlock(&lock);
 279 }
 280
 281 GLuint ResourcePool::create_2d_texture(GLint internal_format, GLsizei width, GLsizei height)
 282 {
 283         assert(width > 0);
 284         assert(height > 0);
 285
 286         pthread_mutex_lock(&lock);
 287         // See if there's a texture on the freelist we can use.
 288         for (list<GLuint>::iterator freelist_it = texture_freelist.begin();
 289              freelist_it != texture_freelist.end();
 290              ++freelist_it) {
 291                 GLuint texture_num = *freelist_it;
 292                 map<GLuint, Texture2D>::const_iterator format_it = texture_formats.find(texture_num);
 293                 assert(format_it != texture_formats.end());
 294                 if (format_it->second.internal_format == internal_format &&
 295                     format_it->second.width == width &&
 296                     format_it->second.height == height) {
 297                         texture_freelist_bytes -= estimate_texture_size(format_it->second);
 298                         texture_freelist.erase(freelist_it);
 299                         pthread_mutex_unlock(&lock);
 300                         return texture_num;
 301                 }
 302         }
 303
 304         // Find any reasonable format given the internal format; OpenGL validates it
 305         // even though we give NULL as pointer.
 306         GLenum format;
 307         switch (internal_format) {
 308         case GL_RGBA32F_ARB:
 309         case GL_RGBA16F_ARB:
 310         case GL_RGBA16:
 311         case GL_RGBA8:
 312         case GL_RGB10_A2:
 313         case GL_SRGB8_ALPHA8:
 314                 format = GL_RGBA;
 315                 break;
 316         case GL_RGB32F:
 317         case GL_RGB16F:
 318         case GL_RGB16:
 319         case GL_R11F_G11F_B10F:
 320         case GL_RGB8:
 321         case GL_RGB10:
 322         case GL_SRGB8:
 323         case GL_RGB565:
 324         case GL_RGB9_E5:
 325                 format = GL_RGB;
 326                 break;
 327         case GL_RG32F:
 328         case GL_RG16F:
 329         case GL_RG16:
 330         case GL_RG8:
 331                 format = GL_RG;
 332                 break;
 333         case GL_R32F:
 334         case GL_R16F:
 335         case GL_R16:
 336         case GL_R8:
 337                 format = GL_RED;
 338                 break;
 339         default:
 340                 // TODO: Add more here as needed.
 341                 assert(false);
 342         }
 343
 344         // Same with type; GLES is stricter than desktop OpenGL here.
 345         GLenum type;
 346         switch (internal_format) {
 347         case GL_RGBA32F_ARB:
 348         case GL_RGBA16F_ARB:
 349         case GL_RGB32F:
 350         case GL_RGB16F:
 351         case GL_R11F_G11F_B10F:
 352         case GL_RGB9_E5:
 353         case GL_RG32F:
 354         case GL_RG16F:
 355         case GL_R32F:
 356         case GL_R16F:
 357                 type = GL_FLOAT;
 358                 break;
 359         case GL_RGBA16:
 360         case GL_RGB16:
 361         case GL_RG16:
 362         case GL_R16:
 363                 type = GL_UNSIGNED_SHORT;
 364                 break;
 365         case GL_SRGB8_ALPHA8:
 366         case GL_SRGB8:
 367         case GL_RGBA8:
 368         case GL_RGB8:
 369         case GL_RGB10_A2:
 370         case GL_RGB10:
 371         case GL_RG8:
 372         case GL_R8:
 373                 type = GL_UNSIGNED_BYTE;
 374                 break;
 375         case GL_RGB565:
 376                 type = GL_UNSIGNED_SHORT_5_6_5;
 377                 break;
 378         default:
 379                 // TODO: Add more here as needed.
 380                 assert(false);
 381         }
 382
 383
 384         GLuint texture_num;
 385         glGenTextures(1, &texture_num);
 386         check_error();
 387         glBindTexture(GL_TEXTURE_2D, texture_num);
 388         check_error();
 389         glTexImage2D(GL_TEXTURE_2D, 0, internal_format, width, height, 0, format, type, NULL);
 390         check_error();
 391         glBindTexture(GL_TEXTURE_2D, 0);
 392         check_error();
 393
 394         Texture2D texture_format;
 395         texture_format.internal_format = internal_format;
 396         texture_format.width = width;
 397         texture_format.height = height;
 398         assert(texture_formats.count(texture_num) == 0);
 399         texture_formats.insert(make_pair(texture_num, texture_format));
 400
 401         pthread_mutex_unlock(&lock);
 402         return texture_num;
 403 }
 404
 405 void ResourcePool::release_2d_texture(GLuint texture_num)
 406 {
 407         pthread_mutex_lock(&lock);
 408         texture_freelist.push_front(texture_num);
 409         assert(texture_formats.count(texture_num) != 0);
 410         texture_freelist_bytes += estimate_texture_size(texture_formats[texture_num]);
 411
 412         while (texture_freelist_bytes > texture_freelist_max_bytes) {
 413                 GLuint free_texture_num = texture_freelist.back();
 414                 texture_freelist.pop_back();
 415                 assert(texture_formats.count(free_texture_num) != 0);
 416                 texture_freelist_bytes -= estimate_texture_size(texture_formats[free_texture_num]);
 417                 texture_formats.erase(free_texture_num);
 418                 glDeleteTextures(1, &free_texture_num);
 419                 check_error();
 420
 421                 // Unlink any lingering FBO related to this texture. We might
 422                 // not be in the right context, so don't delete it right away;
 423                 // the cleanup in release_fbo() (which calls cleanup_unlinked_fbos())
 424                 // will take care of actually doing that later.
 425                 for (map<pair<void *, GLuint>, FBO>::iterator format_it = fbo_formats.begin();
 426                      format_it != fbo_formats.end();
 427                      ++format_it) {
 428                         for (unsigned i = 0; i < num_fbo_attachments; ++i) {
 429                                 if (format_it->second.texture_num[i] == free_texture_num) {
 430                                         format_it->second.texture_num[i] = GL_INVALID_INDEX;
 431                                 }
 432                         }
 433                 }
 434         }
 435         pthread_mutex_unlock(&lock);
 436 }
 437
 438 GLuint ResourcePool::create_fbo(GLuint texture0_num, GLuint texture1_num, GLuint texture2_num, GLuint texture3_num)
 439 {
 440         void *context = get_gl_context_identifier();
 441
 442         // Make sure we are filled from the bottom.
 443         assert(texture0_num != 0);
 444         if (texture1_num == 0) {
 445                 assert(texture2_num == 0);
 446         }
 447         if (texture2_num == 0) {
 448                 assert(texture3_num == 0);
 449         }
 450
 451         pthread_mutex_lock(&lock);
 452         if (fbo_freelist.count(context) != 0) {
 453                 // See if there's an FBO on the freelist we can use.
 454                 list<FBOFormatIterator>::iterator end = fbo_freelist[context].end();
 455                 for (list<FBOFormatIterator>::iterator freelist_it = fbo_freelist[context].begin();
 456                      freelist_it != end; ++freelist_it) {
 457                         FBOFormatIterator fbo_it = *freelist_it;
 458                         if (fbo_it->second.texture_num[0] == texture0_num &&
 459                             fbo_it->second.texture_num[1] == texture1_num &&
 460                             fbo_it->second.texture_num[2] == texture2_num &&
 461                             fbo_it->second.texture_num[3] == texture3_num) {
 462                                 fbo_freelist[context].erase(freelist_it);
 463                                 pthread_mutex_unlock(&lock);
 464                                 return fbo_it->second.fbo_num;
 465                         }
 466                 }
 467         }
 468
 469         // Create a new one.
 470         FBO fbo_format;
 471         fbo_format.texture_num[0] = texture0_num;
 472         fbo_format.texture_num[1] = texture1_num;
 473         fbo_format.texture_num[2] = texture2_num;
 474         fbo_format.texture_num[3] = texture3_num;
 475
 476         glGenFramebuffers(1, &fbo_format.fbo_num);
 477         check_error();
 478         glBindFramebuffer(GL_FRAMEBUFFER, fbo_format.fbo_num);
 479         check_error();
 480
 481         GLenum bufs[num_fbo_attachments];
 482         unsigned num_active_attachments = 0;
 483         for (unsigned i = 0; i < num_fbo_attachments; ++i, ++num_active_attachments) {
 484                 if (fbo_format.texture_num[i] == 0) {
 485                         break;
 486                 }
 487                 glFramebufferTexture2D(
 488                         GL_FRAMEBUFFER,
 489                         GL_COLOR_ATTACHMENT0 + i,
 490                         GL_TEXTURE_2D,
 491                         fbo_format.texture_num[i],
 492                         0);
 493                 check_error();
 494                 bufs[i] = GL_COLOR_ATTACHMENT0 + i;
 495         }
 496
 497         glDrawBuffers(num_active_attachments, bufs);
 498         check_error();
 499
 500         GLenum status = glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT);
 501         assert(status == GL_FRAMEBUFFER_COMPLETE);
 502         glBindFramebuffer(GL_FRAMEBUFFER, 0);
 503         check_error();
 504
 505         pair<void *, GLuint> key(context, fbo_format.fbo_num);
 506         assert(fbo_formats.count(key) == 0);
 507         fbo_formats.insert(make_pair(key, fbo_format));
 508
 509         pthread_mutex_unlock(&lock);
 510         return fbo_format.fbo_num;
 511 }
 512
 513 void ResourcePool::release_fbo(GLuint fbo_num)
 514 {
 515         void *context = get_gl_context_identifier();
 516
 517         pthread_mutex_lock(&lock);
 518         FBOFormatIterator fbo_it = fbo_formats.find(make_pair(context, fbo_num));
 519         assert(fbo_it != fbo_formats.end());
 520         fbo_freelist[context].push_front(fbo_it);
 521
 522         // Now that we're in this context, free up any FBOs that are connected
 523         // to deleted textures (in release_2d_texture).
 524         cleanup_unlinked_fbos(context);
 525
 526         shrink_fbo_freelist(context, fbo_freelist_max_length);
 527         pthread_mutex_unlock(&lock);
 528 }
 529
 530 void ResourcePool::clean_context()
 531 {
 532         void *context = get_gl_context_identifier();
 533
 534         // Currently, we only need to worry about FBOs, as they are the only
 535         // non-shareable resource we hold.
 536         shrink_fbo_freelist(context, 0);
 537         fbo_freelist.erase(context);
 538 }
 539
 540 void ResourcePool::cleanup_unlinked_fbos(void *context)
 541 {
 542         list<FBOFormatIterator>::iterator end = fbo_freelist[context].end();
 543         for (list<FBOFormatIterator>::iterator freelist_it = fbo_freelist[context].begin(); freelist_it != end; ) {
 544                 FBOFormatIterator fbo_it = *freelist_it;
 545
 546                 bool all_unlinked = true;
 547                 for (unsigned i = 0; i < num_fbo_attachments; ++i) {
 548                         if (fbo_it->second.texture_num[i] != 0 &&
 549                             fbo_it->second.texture_num[i] != GL_INVALID_INDEX) {
 550                                 all_unlinked = false;
 551                                 break;
 552                         }
 553                 }
 554                 if (all_unlinked) {
 555                         glDeleteFramebuffers(1, &fbo_it->second.fbo_num);
 556                         check_error();
 557                         fbo_formats.erase(fbo_it);
 558                         fbo_freelist[context].erase(freelist_it++);
 559                 } else {
 560                         freelist_it++;
 561                 }
 562         }
 563 }
 564
 565 void ResourcePool::shrink_fbo_freelist(void *context, size_t max_length)
 566 {
 567         list<FBOFormatIterator> &freelist = fbo_freelist[context];
 568         while (freelist.size() > max_length) {
 569                 FBOFormatIterator free_fbo_it = freelist.back();
 570                 glDeleteFramebuffers(1, &free_fbo_it->second.fbo_num);
 571                 check_error();
 572                 fbo_formats.erase(free_fbo_it);
 573                 freelist.pop_back();
 574         }
 575 }
 576
 577 size_t ResourcePool::estimate_texture_size(const Texture2D &texture_format)
 578 {
 579         size_t bytes_per_pixel;
 580
 581         switch (texture_format.internal_format) {
 582         case GL_RGBA32F_ARB:
 583                 bytes_per_pixel = 16;
 584                 break;
 585         case GL_RGBA16F_ARB:
 586                 bytes_per_pixel = 8;
 587                 break;
 588         case GL_RGB32F_ARB:
 589                 bytes_per_pixel = 12;
 590                 break;
 591         case GL_RGB16F_ARB:
 592                 bytes_per_pixel = 6;
 593                 break;
 594         case GL_R11F_G11F_B10F:
 595                 bytes_per_pixel = 4;
 596                 break;
 597         case GL_RGB9_E5:
 598                 bytes_per_pixel = 4;
 599                 break;
 600         case GL_RGBA8:
 601         case GL_SRGB8_ALPHA8:
 602         case GL_RGB10_A2:
 603         case GL_RGB10:
 604                 bytes_per_pixel = 4;
 605                 break;
 606         case GL_RGB8:
 607         case GL_SRGB8:
 608                 bytes_per_pixel = 3;
 609                 break;
 610         case GL_RG32F:
 611                 bytes_per_pixel = 8;
 612                 break;
 613         case GL_RG16F:
 614                 bytes_per_pixel = 4;
 615                 break;
 616         case GL_R32F:
 617                 bytes_per_pixel = 4;
 618                 break;
 619         case GL_R16F:
 620                 bytes_per_pixel = 2;
 621                 break;
 622         case GL_RG8:
 623                 bytes_per_pixel = 2;
 624                 break;
 625         case GL_R8:
 626                 bytes_per_pixel = 1;
 627                 break;
 628         case GL_RGB565:
 629                 bytes_per_pixel = 2;
 630                 break;
 631         case GL_RGBA16:
 632                 bytes_per_pixel = 8;
 633                 break;
 634         case GL_RGB16:
 635                 bytes_per_pixel = 6;
 636                 break;
 637         case GL_RG16:
 638                 bytes_per_pixel = 4;
 639                 break;
 640         case GL_R16:
 641                 bytes_per_pixel = 2;
 642                 break;
 643         default:
 644                 // TODO: Add more here as needed.
 645                 assert(false);
 646         }
 647
 648         return texture_format.width * texture_format.height * bytes_per_pixel;
 649 }
 650
 651 }  // namespace movit