git.sesse.net Git - nageru/blob - flow.cpp

   1 #define NO_SDL_GLEXT 1
   2
   3 #include <epoxy/gl.h>
   4
   5 #include <SDL2/SDL.h>
   6 #include <SDL2/SDL_error.h>
   7 #include <SDL2/SDL_events.h>
   8 #include <SDL2/SDL_image.h>
   9 #include <SDL2/SDL_keyboard.h>
  10 #include <SDL2/SDL_mouse.h>
  11 #include <SDL2/SDL_video.h>
  12
  13 #include <assert.h>
  14 #include <getopt.h>
  15 #include <stdio.h>
  16 #include <unistd.h>
  17
  18 #include "flow.h"
  19 #include "gpu_timers.h"
  20 #include "util.h"
  21
  22 #include <algorithm>
  23 #include <deque>
  24 #include <memory>
  25 #include <map>
  26 #include <stack>
  27 #include <vector>
  28
  29 #define BUFFER_OFFSET(i) ((char *)nullptr + (i))
  30
  31 using namespace std;
  32
  33 SDL_Window *window;
  34
  35 // Weighting constants for the different parts of the variational refinement.
  36 // These don't correspond 1:1 to the values given in the DIS paper,
  37 // since we have different normalizations and ranges in some cases.
  38 // These are found through a simple grid search on some MPI-Sintel data,
  39 // although the error (EPE) seems to be fairly insensitive to the precise values.
  40 // Only the relative values matter, so we fix alpha (the smoothness constant)
  41 // at unity and tweak the others.
  42 static float vr_alpha = 1.0f, vr_delta = 0.25f, vr_gamma = 0.25f;
  43
  44 bool enable_timing = true;
  45 bool detailed_timing = false;
  46 bool enable_warmup = false;
  47 bool in_warmup = false;
  48 bool enable_variational_refinement = true;  // Just for debugging.
  49 bool enable_interpolation = false;
  50
  51 // Some global OpenGL objects.
  52 // TODO: These should really be part of DISComputeFlow.
  53 GLuint nearest_sampler, linear_sampler, zero_border_sampler;
  54 GLuint vertex_vbo;
  55
  56 // Structures for asynchronous readback. We assume everything is the same size (and GL_RG16F).
  57 struct ReadInProgress {
  58         GLuint pbo;
  59         string filename0, filename1;
  60         string flow_filename, ppm_filename;  // Either may be empty for no write.
  61 };
  62 stack<GLuint> spare_pbos;
  63 deque<ReadInProgress> reads_in_progress;
  64
  65 int find_num_levels(int width, int height)
  66 {
  67         int levels = 1;
  68         for (int w = width, h = height; w > 1 || h > 1; ) {
  69                 w >>= 1;
  70                 h >>= 1;
  71                 ++levels;
  72         }
  73         return levels;
  74 }
  75
  76 string read_file(const string &filename)
  77 {
  78         FILE *fp = fopen(filename.c_str(), "r");
  79         if (fp == nullptr) {
  80                 perror(filename.c_str());
  81                 exit(1);
  82         }
  83
  84         int ret = fseek(fp, 0, SEEK_END);
  85         if (ret == -1) {
  86                 perror("fseek(SEEK_END)");
  87                 exit(1);
  88         }
  89
  90         int size = ftell(fp);
  91
  92         ret = fseek(fp, 0, SEEK_SET);
  93         if (ret == -1) {
  94                 perror("fseek(SEEK_SET)");
  95                 exit(1);
  96         }
  97
  98         string str;
  99         str.resize(size);
 100         ret = fread(&str[0], size, 1, fp);
 101         if (ret == -1) {
 102                 perror("fread");
 103                 exit(1);
 104         }
 105         if (ret == 0) {
 106                 fprintf(stderr, "Short read when trying to read %d bytes from %s\n",
 107                                 size, filename.c_str());
 108                 exit(1);
 109         }
 110         fclose(fp);
 111
 112         return str;
 113 }
 114
 115
 116 GLuint compile_shader(const string &shader_src, GLenum type)
 117 {
 118         GLuint obj = glCreateShader(type);
 119         const GLchar* source[] = { shader_src.data() };
 120         const GLint length[] = { (GLint)shader_src.size() };
 121         glShaderSource(obj, 1, source, length);
 122         glCompileShader(obj);
 123
 124         GLchar info_log[4096];
 125         GLsizei log_length = sizeof(info_log) - 1;
 126         glGetShaderInfoLog(obj, log_length, &log_length, info_log);
 127         info_log[log_length] = 0;
 128         if (strlen(info_log) > 0) {
 129                 fprintf(stderr, "Shader compile log: %s\n", info_log);
 130         }
 131
 132         GLint status;
 133         glGetShaderiv(obj, GL_COMPILE_STATUS, &status);
 134         if (status == GL_FALSE) {
 135                 // Add some line numbers to easier identify compile errors.
 136                 string src_with_lines = "/*   1 */ ";
 137                 size_t lineno = 1;
 138                 for (char ch : shader_src) {
 139                         src_with_lines.push_back(ch);
 140                         if (ch == '\n') {
 141                                 char buf[32];
 142                                 snprintf(buf, sizeof(buf), "/* %3zu */ ", ++lineno);
 143                                 src_with_lines += buf;
 144                         }
 145                 }
 146
 147                 fprintf(stderr, "Failed to compile shader:\n%s\n", src_with_lines.c_str());
 148                 exit(1);
 149         }
 150
 151         return obj;
 152 }
 153
 154 enum MipmapPolicy {
 155         WITHOUT_MIPMAPS,
 156         WITH_MIPMAPS
 157 };
 158
 159 GLuint load_texture(const char *filename, unsigned *width_ret, unsigned *height_ret, MipmapPolicy mipmaps)
 160 {
 161         SDL_Surface *surf = IMG_Load(filename);
 162         if (surf == nullptr) {
 163                 fprintf(stderr, "IMG_Load(%s): %s\n", filename, IMG_GetError());
 164                 exit(1);
 165         }
 166
 167         // For whatever reason, SDL doesn't support converting to YUV surfaces
 168         // nor grayscale, so we'll do it ourselves.
 169         SDL_Surface *rgb_surf = SDL_ConvertSurfaceFormat(surf, SDL_PIXELFORMAT_RGBA32, /*flags=*/0);
 170         if (rgb_surf == nullptr) {
 171                 fprintf(stderr, "SDL_ConvertSurfaceFormat(%s): %s\n", filename, SDL_GetError());
 172                 exit(1);
 173         }
 174
 175         SDL_FreeSurface(surf);
 176
 177         unsigned width = rgb_surf->w, height = rgb_surf->h;
 178         const uint8_t *sptr = (uint8_t *)rgb_surf->pixels;
 179         unique_ptr<uint8_t[]> pix(new uint8_t[width * height * 4]);
 180
 181         // Extract the Y component, and convert to bottom-left origin.
 182         for (unsigned y = 0; y < height; ++y) {
 183                 unsigned y2 = height - 1 - y;
 184                 memcpy(pix.get() + y * width * 4, sptr + y2 * rgb_surf->pitch, width * 4);
 185         }
 186         SDL_FreeSurface(rgb_surf);
 187
 188         int num_levels = (mipmaps == WITH_MIPMAPS) ? find_num_levels(width, height) : 1;
 189
 190         GLuint tex;
 191         glCreateTextures(GL_TEXTURE_2D, 1, &tex);
 192         glTextureStorage2D(tex, num_levels, GL_RGBA8, width, height);
 193         glTextureSubImage2D(tex, 0, 0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, pix.get());
 194
 195         if (mipmaps == WITH_MIPMAPS) {
 196                 glGenerateTextureMipmap(tex);
 197         }
 198
 199         *width_ret = width;
 200         *height_ret = height;
 201
 202         return tex;
 203 }
 204
 205 GLuint link_program(GLuint vs_obj, GLuint fs_obj)
 206 {
 207         GLuint program = glCreateProgram();
 208         glAttachShader(program, vs_obj);
 209         glAttachShader(program, fs_obj);
 210         glLinkProgram(program);
 211         GLint success;
 212         glGetProgramiv(program, GL_LINK_STATUS, &success);
 213         if (success == GL_FALSE) {
 214                 GLchar error_log[1024] = {0};
 215                 glGetProgramInfoLog(program, 1024, nullptr, error_log);
 216                 fprintf(stderr, "Error linking program: %s\n", error_log);
 217                 exit(1);
 218         }
 219         return program;
 220 }
 221
 222 void bind_sampler(GLuint program, GLint location, GLuint texture_unit, GLuint tex, GLuint sampler)
 223 {
 224         if (location == -1) {
 225                 return;
 226         }
 227
 228         glBindTextureUnit(texture_unit, tex);
 229         glBindSampler(texture_unit, sampler);
 230         glProgramUniform1i(program, location, texture_unit);
 231 }
 232
 233 template<size_t num_elements>
 234 void PersistentFBOSet<num_elements>::render_to(const array<GLuint, num_elements> &textures)
 235 {
 236         auto it = fbos.find(textures);
 237         if (it != fbos.end()) {
 238                 glBindFramebuffer(GL_FRAMEBUFFER, it->second);
 239                 return;
 240         }
 241
 242         GLuint fbo;
 243         glCreateFramebuffers(1, &fbo);
 244         GLenum bufs[num_elements];
 245         for (size_t i = 0; i < num_elements; ++i) {
 246                 glNamedFramebufferTexture(fbo, GL_COLOR_ATTACHMENT0 + i, textures[i], 0);
 247                 bufs[i] = GL_COLOR_ATTACHMENT0 + i;
 248         }
 249         glNamedFramebufferDrawBuffers(fbo, num_elements, bufs);
 250
 251         fbos[textures] = fbo;
 252         glBindFramebuffer(GL_FRAMEBUFFER, fbo);
 253 }
 254
 255 template<size_t num_elements>
 256 void PersistentFBOSetWithDepth<num_elements>::render_to(GLuint depth_rb, const array<GLuint, num_elements> &textures)
 257 {
 258         auto key = make_pair(depth_rb, textures);
 259
 260         auto it = fbos.find(key);
 261         if (it != fbos.end()) {
 262                 glBindFramebuffer(GL_FRAMEBUFFER, it->second);
 263                 return;
 264         }
 265
 266         GLuint fbo;
 267         glCreateFramebuffers(1, &fbo);
 268         GLenum bufs[num_elements];
 269         glNamedFramebufferRenderbuffer(fbo, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depth_rb);
 270         for (size_t i = 0; i < num_elements; ++i) {
 271                 glNamedFramebufferTexture(fbo, GL_COLOR_ATTACHMENT0 + i, textures[i], 0);
 272                 bufs[i] = GL_COLOR_ATTACHMENT0 + i;
 273         }
 274         glNamedFramebufferDrawBuffers(fbo, num_elements, bufs);
 275
 276         fbos[key] = fbo;
 277         glBindFramebuffer(GL_FRAMEBUFFER, fbo);
 278 }
 279
 280 GrayscaleConversion::GrayscaleConversion()
 281 {
 282         gray_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 283         gray_fs_obj = compile_shader(read_file("gray.frag"), GL_FRAGMENT_SHADER);
 284         gray_program = link_program(gray_vs_obj, gray_fs_obj);
 285
 286         // Set up the VAO containing all the required position/texcoord data.
 287         glCreateVertexArrays(1, &gray_vao);
 288         glBindVertexArray(gray_vao);
 289
 290         GLint position_attrib = glGetAttribLocation(gray_program, "position");
 291         glEnableVertexArrayAttrib(gray_vao, position_attrib);
 292         glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
 293
 294         uniform_tex = glGetUniformLocation(gray_program, "tex");
 295 }
 296
 297 void GrayscaleConversion::exec(GLint tex, GLint gray_tex, int width, int height, int num_layers)
 298 {
 299         glUseProgram(gray_program);
 300         bind_sampler(gray_program, uniform_tex, 0, tex, nearest_sampler);
 301
 302         glViewport(0, 0, width, height);
 303         fbos.render_to(gray_tex);
 304         glBindVertexArray(gray_vao);
 305         glDisable(GL_BLEND);
 306         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, num_layers);
 307 }
 308
 309 Sobel::Sobel()
 310 {
 311         sobel_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 312         sobel_fs_obj = compile_shader(read_file("sobel.frag"), GL_FRAGMENT_SHADER);
 313         sobel_program = link_program(sobel_vs_obj, sobel_fs_obj);
 314
 315         uniform_tex = glGetUniformLocation(sobel_program, "tex");
 316 }
 317
 318 void Sobel::exec(GLint tex_view, GLint grad_tex, int level_width, int level_height, int num_layers)
 319 {
 320         glUseProgram(sobel_program);
 321         bind_sampler(sobel_program, uniform_tex, 0, tex_view, nearest_sampler);
 322
 323         glViewport(0, 0, level_width, level_height);
 324         fbos.render_to(grad_tex);
 325         glDisable(GL_BLEND);
 326         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, num_layers);
 327 }
 328
 329 MotionSearch::MotionSearch(const OperatingPoint &op)
 330         : op(op)
 331 {
 332         motion_vs_obj = compile_shader(read_file("motion_search.vert"), GL_VERTEX_SHADER);
 333         motion_fs_obj = compile_shader(read_file("motion_search.frag"), GL_FRAGMENT_SHADER);
 334         motion_search_program = link_program(motion_vs_obj, motion_fs_obj);
 335
 336         uniform_inv_image_size = glGetUniformLocation(motion_search_program, "inv_image_size");
 337         uniform_inv_prev_level_size = glGetUniformLocation(motion_search_program, "inv_prev_level_size");
 338         uniform_out_flow_size = glGetUniformLocation(motion_search_program, "out_flow_size");
 339         uniform_image_tex = glGetUniformLocation(motion_search_program, "image_tex");
 340         uniform_grad_tex = glGetUniformLocation(motion_search_program, "grad_tex");
 341         uniform_flow_tex = glGetUniformLocation(motion_search_program, "flow_tex");
 342         uniform_patch_size = glGetUniformLocation(motion_search_program, "patch_size");
 343         uniform_num_iterations = glGetUniformLocation(motion_search_program, "num_iterations");
 344 }
 345
 346 void MotionSearch::exec(GLuint tex_view, GLuint grad_tex, GLuint flow_tex, GLuint flow_out_tex, int level_width, int level_height, int prev_level_width, int prev_level_height, int width_patches, int height_patches, int num_layers)
 347 {
 348         glUseProgram(motion_search_program);
 349
 350         bind_sampler(motion_search_program, uniform_image_tex, 0, tex_view, linear_sampler);
 351         bind_sampler(motion_search_program, uniform_grad_tex, 1, grad_tex, nearest_sampler);
 352         bind_sampler(motion_search_program, uniform_flow_tex, 2, flow_tex, linear_sampler);
 353
 354         glProgramUniform2f(motion_search_program, uniform_inv_image_size, 1.0f / level_width, 1.0f / level_height);
 355         glProgramUniform2f(motion_search_program, uniform_inv_prev_level_size, 1.0f / prev_level_width, 1.0f / prev_level_height);
 356         glProgramUniform2f(motion_search_program, uniform_out_flow_size, width_patches, height_patches);
 357         glProgramUniform1ui(motion_search_program, uniform_patch_size, op.patch_size_pixels);
 358         glProgramUniform1ui(motion_search_program, uniform_num_iterations, op.search_iterations);
 359
 360         glViewport(0, 0, width_patches, height_patches);
 361         fbos.render_to(flow_out_tex);
 362         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, num_layers);
 363 }
 364
 365 Densify::Densify(const OperatingPoint &op)
 366         : op(op)
 367 {
 368         densify_vs_obj = compile_shader(read_file("densify.vert"), GL_VERTEX_SHADER);
 369         densify_fs_obj = compile_shader(read_file("densify.frag"), GL_FRAGMENT_SHADER);
 370         densify_program = link_program(densify_vs_obj, densify_fs_obj);
 371
 372         uniform_patch_size = glGetUniformLocation(densify_program, "patch_size");
 373         uniform_image_tex = glGetUniformLocation(densify_program, "image_tex");
 374         uniform_flow_tex = glGetUniformLocation(densify_program, "flow_tex");
 375 }
 376
 377 void Densify::exec(GLuint tex_view, GLuint flow_tex, GLuint dense_flow_tex, int level_width, int level_height, int width_patches, int height_patches, int num_layers)
 378 {
 379         glUseProgram(densify_program);
 380
 381         bind_sampler(densify_program, uniform_image_tex, 0, tex_view, linear_sampler);
 382         bind_sampler(densify_program, uniform_flow_tex, 1, flow_tex, nearest_sampler);
 383
 384         glProgramUniform2f(densify_program, uniform_patch_size,
 385                 float(op.patch_size_pixels) / level_width,
 386                 float(op.patch_size_pixels) / level_height);
 387
 388         glViewport(0, 0, level_width, level_height);
 389         glEnable(GL_BLEND);
 390         glBlendFunc(GL_ONE, GL_ONE);
 391         fbos.render_to(dense_flow_tex);
 392         glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
 393         glClear(GL_COLOR_BUFFER_BIT);
 394         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width_patches * height_patches * num_layers);
 395 }
 396
 397 Prewarp::Prewarp()
 398 {
 399         prewarp_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 400         prewarp_fs_obj = compile_shader(read_file("prewarp.frag"), GL_FRAGMENT_SHADER);
 401         prewarp_program = link_program(prewarp_vs_obj, prewarp_fs_obj);
 402
 403         uniform_image_tex = glGetUniformLocation(prewarp_program, "image_tex");
 404         uniform_flow_tex = glGetUniformLocation(prewarp_program, "flow_tex");
 405 }
 406
 407 void Prewarp::exec(GLuint tex_view, GLuint flow_tex, GLuint I_tex, GLuint I_t_tex, GLuint normalized_flow_tex, int level_width, int level_height, int num_layers)
 408 {
 409         glUseProgram(prewarp_program);
 410
 411         bind_sampler(prewarp_program, uniform_image_tex, 0, tex_view, linear_sampler);
 412         bind_sampler(prewarp_program, uniform_flow_tex, 1, flow_tex, nearest_sampler);
 413
 414         glViewport(0, 0, level_width, level_height);
 415         glDisable(GL_BLEND);
 416         fbos.render_to(I_tex, I_t_tex, normalized_flow_tex);
 417         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, num_layers);
 418 }
 419
 420 Derivatives::Derivatives()
 421 {
 422         derivatives_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 423         derivatives_fs_obj = compile_shader(read_file("derivatives.frag"), GL_FRAGMENT_SHADER);
 424         derivatives_program = link_program(derivatives_vs_obj, derivatives_fs_obj);
 425
 426         uniform_tex = glGetUniformLocation(derivatives_program, "tex");
 427 }
 428
 429 void Derivatives::exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, int level_width, int level_height, int num_layers)
 430 {
 431         glUseProgram(derivatives_program);
 432
 433         bind_sampler(derivatives_program, uniform_tex, 0, input_tex, nearest_sampler);
 434
 435         glViewport(0, 0, level_width, level_height);
 436         glDisable(GL_BLEND);
 437         fbos.render_to(I_x_y_tex, beta_0_tex);
 438         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, num_layers);
 439 }
 440
 441 ComputeDiffusivity::ComputeDiffusivity()
 442 {
 443         diffusivity_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 444         diffusivity_fs_obj = compile_shader(read_file("diffusivity.frag"), GL_FRAGMENT_SHADER);
 445         diffusivity_program = link_program(diffusivity_vs_obj, diffusivity_fs_obj);
 446
 447         uniform_flow_tex = glGetUniformLocation(diffusivity_program, "flow_tex");
 448         uniform_diff_flow_tex = glGetUniformLocation(diffusivity_program, "diff_flow_tex");
 449         uniform_alpha = glGetUniformLocation(diffusivity_program, "alpha");
 450         uniform_zero_diff_flow = glGetUniformLocation(diffusivity_program, "zero_diff_flow");
 451 }
 452
 453 void ComputeDiffusivity::exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint diffusivity_tex, int level_width, int level_height, bool zero_diff_flow, int num_layers)
 454 {
 455         glUseProgram(diffusivity_program);
 456
 457         bind_sampler(diffusivity_program, uniform_flow_tex, 0, flow_tex, nearest_sampler);
 458         bind_sampler(diffusivity_program, uniform_diff_flow_tex, 1, diff_flow_tex, nearest_sampler);
 459         glProgramUniform1f(diffusivity_program, uniform_alpha, vr_alpha);
 460         glProgramUniform1i(diffusivity_program, uniform_zero_diff_flow, zero_diff_flow);
 461
 462         glViewport(0, 0, level_width, level_height);
 463
 464         glDisable(GL_BLEND);
 465         fbos.render_to(diffusivity_tex);
 466         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, num_layers);
 467 }
 468
 469 SetupEquations::SetupEquations()
 470 {
 471         equations_vs_obj = compile_shader(read_file("equations.vert"), GL_VERTEX_SHADER);
 472         equations_fs_obj = compile_shader(read_file("equations.frag"), GL_FRAGMENT_SHADER);
 473         equations_program = link_program(equations_vs_obj, equations_fs_obj);
 474
 475         uniform_I_x_y_tex = glGetUniformLocation(equations_program, "I_x_y_tex");
 476         uniform_I_t_tex = glGetUniformLocation(equations_program, "I_t_tex");
 477         uniform_diff_flow_tex = glGetUniformLocation(equations_program, "diff_flow_tex");
 478         uniform_base_flow_tex = glGetUniformLocation(equations_program, "base_flow_tex");
 479         uniform_beta_0_tex = glGetUniformLocation(equations_program, "beta_0_tex");
 480         uniform_diffusivity_tex = glGetUniformLocation(equations_program, "diffusivity_tex");
 481         uniform_gamma = glGetUniformLocation(equations_program, "gamma");
 482         uniform_delta = glGetUniformLocation(equations_program, "delta");
 483         uniform_zero_diff_flow = glGetUniformLocation(equations_program, "zero_diff_flow");
 484 }
 485
 486 void SetupEquations::exec(GLuint I_x_y_tex, GLuint I_t_tex, GLuint diff_flow_tex, GLuint base_flow_tex, GLuint beta_0_tex, GLuint diffusivity_tex, GLuint equation_red_tex, GLuint equation_black_tex, int level_width, int level_height, bool zero_diff_flow, int num_layers)
 487 {
 488         glUseProgram(equations_program);
 489
 490         bind_sampler(equations_program, uniform_I_x_y_tex, 0, I_x_y_tex, nearest_sampler);
 491         bind_sampler(equations_program, uniform_I_t_tex, 1, I_t_tex, nearest_sampler);
 492         bind_sampler(equations_program, uniform_diff_flow_tex, 2, diff_flow_tex, nearest_sampler);
 493         bind_sampler(equations_program, uniform_base_flow_tex, 3, base_flow_tex, nearest_sampler);
 494         bind_sampler(equations_program, uniform_beta_0_tex, 4, beta_0_tex, nearest_sampler);
 495         bind_sampler(equations_program, uniform_diffusivity_tex, 5, diffusivity_tex, zero_border_sampler);
 496         glProgramUniform1f(equations_program, uniform_delta, vr_delta);
 497         glProgramUniform1f(equations_program, uniform_gamma, vr_gamma);
 498         glProgramUniform1i(equations_program, uniform_zero_diff_flow, zero_diff_flow);
 499
 500         glViewport(0, 0, (level_width + 1) / 2, level_height);
 501         glDisable(GL_BLEND);
 502         fbos.render_to(equation_red_tex, equation_black_tex);
 503         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, num_layers);
 504 }
 505
 506 SOR::SOR()
 507 {
 508         sor_vs_obj = compile_shader(read_file("sor.vert"), GL_VERTEX_SHADER);
 509         sor_fs_obj = compile_shader(read_file("sor.frag"), GL_FRAGMENT_SHADER);
 510         sor_program = link_program(sor_vs_obj, sor_fs_obj);
 511
 512         uniform_diff_flow_tex = glGetUniformLocation(sor_program, "diff_flow_tex");
 513         uniform_equation_red_tex = glGetUniformLocation(sor_program, "equation_red_tex");
 514         uniform_equation_black_tex = glGetUniformLocation(sor_program, "equation_black_tex");
 515         uniform_diffusivity_tex = glGetUniformLocation(sor_program, "diffusivity_tex");
 516         uniform_phase = glGetUniformLocation(sor_program, "phase");
 517         uniform_num_nonzero_phases = glGetUniformLocation(sor_program, "num_nonzero_phases");
 518 }
 519
 520 void SOR::exec(GLuint diff_flow_tex, GLuint equation_red_tex, GLuint equation_black_tex, GLuint diffusivity_tex, int level_width, int level_height, int num_iterations, bool zero_diff_flow, int num_layers, ScopedTimer *sor_timer)
 521 {
 522         glUseProgram(sor_program);
 523
 524         bind_sampler(sor_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler);
 525         bind_sampler(sor_program, uniform_diffusivity_tex, 1, diffusivity_tex, zero_border_sampler);
 526         bind_sampler(sor_program, uniform_equation_red_tex, 2, equation_red_tex, nearest_sampler);
 527         bind_sampler(sor_program, uniform_equation_black_tex, 3, equation_black_tex, nearest_sampler);
 528
 529         if (!zero_diff_flow) {
 530                 glProgramUniform1i(sor_program, uniform_num_nonzero_phases, 2);
 531         }
 532
 533         // NOTE: We bind to the texture we are rendering from, but we never write any value
 534         // that we read in the same shader pass (we call discard for red values when we compute
 535         // black, and vice versa), and we have barriers between the passes, so we're fine
 536         // as per the spec.
 537         glViewport(0, 0, level_width, level_height);
 538         glDisable(GL_BLEND);
 539         fbos.render_to(diff_flow_tex);
 540
 541         for (int i = 0; i < num_iterations; ++i) {
 542                 {
 543                         ScopedTimer timer("Red pass", sor_timer);
 544                         if (zero_diff_flow && i == 0) {
 545                                 glProgramUniform1i(sor_program, uniform_num_nonzero_phases, 0);
 546                         }
 547                         glProgramUniform1i(sor_program, uniform_phase, 0);
 548                         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, num_layers);
 549                         glTextureBarrier();
 550                 }
 551                 {
 552                         ScopedTimer timer("Black pass", sor_timer);
 553                         if (zero_diff_flow && i == 0) {
 554                                 glProgramUniform1i(sor_program, uniform_num_nonzero_phases, 1);
 555                         }
 556                         glProgramUniform1i(sor_program, uniform_phase, 1);
 557                         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, num_layers);
 558                         if (zero_diff_flow && i == 0) {
 559                                 glProgramUniform1i(sor_program, uniform_num_nonzero_phases, 2);
 560                         }
 561                         if (i != num_iterations - 1) {
 562                                 glTextureBarrier();
 563                         }
 564                 }
 565         }
 566 }
 567
 568 AddBaseFlow::AddBaseFlow()
 569 {
 570         add_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 571         add_flow_fs_obj = compile_shader(read_file("add_base_flow.frag"), GL_FRAGMENT_SHADER);
 572         add_flow_program = link_program(add_flow_vs_obj, add_flow_fs_obj);
 573
 574         uniform_diff_flow_tex = glGetUniformLocation(add_flow_program, "diff_flow_tex");
 575 }
 576
 577 void AddBaseFlow::exec(GLuint base_flow_tex, GLuint diff_flow_tex, int level_width, int level_height, int num_layers)
 578 {
 579         glUseProgram(add_flow_program);
 580
 581         bind_sampler(add_flow_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler);
 582
 583         glViewport(0, 0, level_width, level_height);
 584         glEnable(GL_BLEND);
 585         glBlendFunc(GL_ONE, GL_ONE);
 586         fbos.render_to(base_flow_tex);
 587
 588         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, num_layers);
 589 }
 590
 591 ResizeFlow::ResizeFlow()
 592 {
 593         resize_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 594         resize_flow_fs_obj = compile_shader(read_file("resize_flow.frag"), GL_FRAGMENT_SHADER);
 595         resize_flow_program = link_program(resize_flow_vs_obj, resize_flow_fs_obj);
 596
 597         uniform_flow_tex = glGetUniformLocation(resize_flow_program, "flow_tex");
 598         uniform_scale_factor = glGetUniformLocation(resize_flow_program, "scale_factor");
 599 }
 600
 601 void ResizeFlow::exec(GLuint flow_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height, int num_layers)
 602 {
 603         glUseProgram(resize_flow_program);
 604
 605         bind_sampler(resize_flow_program, uniform_flow_tex, 0, flow_tex, nearest_sampler);
 606
 607         glProgramUniform2f(resize_flow_program, uniform_scale_factor, float(output_width) / input_width, float(output_height) / input_height);
 608
 609         glViewport(0, 0, output_width, output_height);
 610         glDisable(GL_BLEND);
 611         fbos.render_to(out_tex);
 612
 613         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, num_layers);
 614 }
 615
 616 DISComputeFlow::DISComputeFlow(int width, int height, const OperatingPoint &op)
 617         : width(width), height(height), op(op), motion_search(op), densify(op)
 618 {
 619         // Make some samplers.
 620         glCreateSamplers(1, &nearest_sampler);
 621         glSamplerParameteri(nearest_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
 622         glSamplerParameteri(nearest_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
 623         glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 624         glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 625
 626         glCreateSamplers(1, &linear_sampler);
 627         glSamplerParameteri(linear_sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 628         glSamplerParameteri(linear_sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 629         glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 630         glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 631
 632         // The smoothness is sampled so that once we get to a smoothness involving
 633         // a value outside the border, the diffusivity between the two becomes zero.
 634         // Similarly, gradients are zero outside the border, since the edge is taken
 635         // to be constant.
 636         glCreateSamplers(1, &zero_border_sampler);
 637         glSamplerParameteri(zero_border_sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 638         glSamplerParameteri(zero_border_sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
 639         glSamplerParameteri(zero_border_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
 640         glSamplerParameteri(zero_border_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
 641         float zero[] = { 0.0f, 0.0f, 0.0f, 0.0f };  // Note that zero alpha means we can also see whether we sampled outside the border or not.
 642         glSamplerParameterfv(zero_border_sampler, GL_TEXTURE_BORDER_COLOR, zero);
 643
 644         // Initial flow is zero, 1x1.
 645         glCreateTextures(GL_TEXTURE_2D_ARRAY, 1, &initial_flow_tex);
 646         glTextureStorage3D(initial_flow_tex, 1, GL_RG16F, 1, 1, 1);
 647         glClearTexImage(initial_flow_tex, 0, GL_RG, GL_FLOAT, nullptr);
 648
 649         // Set up the vertex data that will be shared between all passes.
 650         float vertices[] = {
 651                 0.0f, 1.0f,
 652                 0.0f, 0.0f,
 653                 1.0f, 1.0f,
 654                 1.0f, 0.0f,
 655         };
 656         glCreateBuffers(1, &vertex_vbo);
 657         glNamedBufferData(vertex_vbo, sizeof(vertices), vertices, GL_STATIC_DRAW);
 658
 659         glCreateVertexArrays(1, &vao);
 660         glBindVertexArray(vao);
 661         glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
 662
 663         GLint position_attrib = 0;  // Hard-coded in every vertex shader.
 664         glEnableVertexArrayAttrib(vao, position_attrib);
 665         glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
 666 }
 667
 668 GLuint DISComputeFlow::exec(GLuint tex, FlowDirection flow_direction, ResizeStrategy resize_strategy)
 669 {
 670         int num_layers = (flow_direction == FORWARD_AND_BACKWARD) ? 2 : 1;
 671         int prev_level_width = 1, prev_level_height = 1;
 672         GLuint prev_level_flow_tex = initial_flow_tex;
 673
 674         GPUTimers timers;
 675
 676         glBindVertexArray(vao);
 677
 678         ScopedTimer total_timer("Compute flow", &timers);
 679         for (int level = op.coarsest_level; level >= int(op.finest_level); --level) {
 680                 char timer_name[256];
 681                 snprintf(timer_name, sizeof(timer_name), "Level %d (%d x %d)", level, width >> level, height >> level);
 682                 ScopedTimer level_timer(timer_name, &total_timer);
 683
 684                 int level_width = width >> level;
 685                 int level_height = height >> level;
 686                 float patch_spacing_pixels = op.patch_size_pixels * (1.0f - op.patch_overlap_ratio);
 687
 688                 // Make sure we have patches at least every Nth pixel, e.g. for width=9
 689                 // and patch_spacing=3 (the default), we put out patch centers in
 690                 // x=0, x=3, x=6, x=9, which is four patches. The fragment shader will
 691                 // lock all the centers to integer coordinates if needed.
 692                 int width_patches = 1 + ceil(level_width / patch_spacing_pixels);
 693                 int height_patches = 1 + ceil(level_height / patch_spacing_pixels);
 694
 695                 // Make sure we always read from the correct level; the chosen
 696                 // mipmapping could otherwise be rather unpredictable, especially
 697                 // during motion search.
 698                 GLuint tex_view;
 699                 glGenTextures(1, &tex_view);
 700                 glTextureView(tex_view, GL_TEXTURE_2D_ARRAY, tex, GL_R8, level, 1, 0, 2);
 701
 702                 // Create a new texture to hold the gradients.
 703                 GLuint grad_tex = pool.get_texture(GL_R32UI, level_width, level_height, num_layers);
 704
 705                 // Find the derivative.
 706                 {
 707                         ScopedTimer timer("Sobel", &level_timer);
 708                         sobel.exec(tex_view, grad_tex, level_width, level_height, num_layers);
 709                 }
 710
 711                 // Motion search to find the initial flow. We use the flow from the previous
 712                 // level (sampled bilinearly; no fancy tricks) as a guide, then search from there.
 713
 714                 // Create an output flow texture.
 715                 GLuint flow_out_tex = pool.get_texture(GL_RGB16F, width_patches, height_patches, num_layers);
 716
 717                 // And draw.
 718                 {
 719                         ScopedTimer timer("Motion search", &level_timer);
 720                         motion_search.exec(tex_view, grad_tex, prev_level_flow_tex, flow_out_tex, level_width, level_height, prev_level_width, prev_level_height, width_patches, height_patches, num_layers);
 721                 }
 722                 pool.release_texture(grad_tex);
 723
 724                 // Densification.
 725
 726                 // Set up an output texture (cleared in Densify).
 727                 GLuint dense_flow_tex = pool.get_texture(GL_RGB16F, level_width, level_height, num_layers);
 728
 729                 // And draw.
 730                 {
 731                         ScopedTimer timer("Densification", &level_timer);
 732                         densify.exec(tex_view, flow_out_tex, dense_flow_tex, level_width, level_height, width_patches, height_patches, num_layers);
 733                 }
 734                 pool.release_texture(flow_out_tex);
 735
 736                 // Everything below here in the loop belongs to variational refinement.
 737                 ScopedTimer varref_timer("Variational refinement", &level_timer);
 738
 739                 // Prewarping; create I and I_t, and a normalized base flow (so we don't
 740                 // have to normalize it over and over again, and also save some bandwidth).
 741                 //
 742                 // During the entire rest of the variational refinement, flow will be measured
 743                 // in pixels, not 0..1 normalized OpenGL texture coordinates.
 744                 // This is because variational refinement depends so heavily on derivatives,
 745                 // which are measured in intensity levels per pixel.
 746                 GLuint I_tex = pool.get_texture(GL_R16F, level_width, level_height, num_layers);
 747                 GLuint I_t_tex = pool.get_texture(GL_R16F, level_width, level_height, num_layers);
 748                 GLuint base_flow_tex = pool.get_texture(GL_RG16F, level_width, level_height, num_layers);
 749                 {
 750                         ScopedTimer timer("Prewarping", &varref_timer);
 751                         prewarp.exec(tex_view, dense_flow_tex, I_tex, I_t_tex, base_flow_tex, level_width, level_height, num_layers);
 752                 }
 753                 pool.release_texture(dense_flow_tex);
 754                 glDeleteTextures(1, &tex_view);
 755
 756                 // Calculate I_x and I_y. We're only calculating first derivatives;
 757                 // the others will be taken on-the-fly in order to sample from fewer
 758                 // textures overall, since sampling from the L1 cache is cheap.
 759                 // (TODO: Verify that this is indeed faster than making separate
 760                 // double-derivative textures.)
 761                 GLuint I_x_y_tex = pool.get_texture(GL_RG16F, level_width, level_height, num_layers);
 762                 GLuint beta_0_tex = pool.get_texture(GL_R16F, level_width, level_height, num_layers);
 763                 {
 764                         ScopedTimer timer("First derivatives", &varref_timer);
 765                         derivatives.exec(I_tex, I_x_y_tex, beta_0_tex, level_width, level_height, num_layers);
 766                 }
 767                 pool.release_texture(I_tex);
 768
 769                 // We need somewhere to store du and dv (the flow increment, relative
 770                 // to the non-refined base flow u0 and v0). It's initially garbage,
 771                 // but not read until we've written something sane to it.
 772                 GLuint diff_flow_tex = pool.get_texture(GL_RG16F, level_width, level_height, num_layers);
 773
 774                 // And for diffusivity.
 775                 GLuint diffusivity_tex = pool.get_texture(GL_R16F, level_width, level_height, num_layers);
 776
 777                 // And finally for the equation set. See SetupEquations for
 778                 // the storage format.
 779                 GLuint equation_red_tex = pool.get_texture(GL_RGBA32UI, (level_width + 1) / 2, level_height, num_layers);
 780                 GLuint equation_black_tex = pool.get_texture(GL_RGBA32UI, (level_width + 1) / 2, level_height, num_layers);
 781
 782                 for (int outer_idx = 0; outer_idx < level + 1; ++outer_idx) {
 783                         // Calculate the diffusivity term for each pixel.
 784                         {
 785                                 ScopedTimer timer("Compute diffusivity", &varref_timer);
 786                                 compute_diffusivity.exec(base_flow_tex, diff_flow_tex, diffusivity_tex, level_width, level_height, outer_idx == 0, num_layers);
 787                         }
 788
 789                         // Set up the 2x2 equation system for each pixel.
 790                         {
 791                                 ScopedTimer timer("Set up equations", &varref_timer);
 792                                 setup_equations.exec(I_x_y_tex, I_t_tex, diff_flow_tex, base_flow_tex, beta_0_tex, diffusivity_tex, equation_red_tex, equation_black_tex, level_width, level_height, outer_idx == 0, num_layers);
 793                         }
 794
 795                         // Run a few SOR iterations. Note that these are to/from the same texture.
 796                         {
 797                                 ScopedTimer timer("SOR", &varref_timer);
 798                                 sor.exec(diff_flow_tex, equation_red_tex, equation_black_tex, diffusivity_tex, level_width, level_height, 5, outer_idx == 0, num_layers, &timer);
 799                         }
 800                 }
 801
 802                 pool.release_texture(I_t_tex);
 803                 pool.release_texture(I_x_y_tex);
 804                 pool.release_texture(beta_0_tex);
 805                 pool.release_texture(diffusivity_tex);
 806                 pool.release_texture(equation_red_tex);
 807                 pool.release_texture(equation_black_tex);
 808
 809                 // Add the differential flow found by the variational refinement to the base flow,
 810                 // giving the final flow estimate for this level.
 811                 // The output is in diff_flow_tex; we don't need to make a new texture.
 812                 //
 813                 // Disabling this doesn't save any time (although we could easily make it so that
 814                 // it is more efficient), but it helps debug the motion search.
 815                 if (op.variational_refinement) {
 816                         ScopedTimer timer("Add differential flow", &varref_timer);
 817                         add_base_flow.exec(base_flow_tex, diff_flow_tex, level_width, level_height, num_layers);
 818                 }
 819                 pool.release_texture(diff_flow_tex);
 820
 821                 if (prev_level_flow_tex != initial_flow_tex) {
 822                         pool.release_texture(prev_level_flow_tex);
 823                 }
 824                 prev_level_flow_tex = base_flow_tex;
 825                 prev_level_width = level_width;
 826                 prev_level_height = level_height;
 827         }
 828         total_timer.end();
 829
 830         if (!in_warmup) {
 831                 timers.print();
 832         }
 833
 834         // Scale up the flow to the final size (if needed).
 835         if (op.finest_level == 0 || resize_strategy == DO_NOT_RESIZE_FLOW) {
 836                 return prev_level_flow_tex;
 837         } else {
 838                 GLuint final_tex = pool.get_texture(GL_RG16F, width, height, num_layers);
 839                 resize_flow.exec(prev_level_flow_tex, final_tex, prev_level_width, prev_level_height, width, height, num_layers);
 840                 pool.release_texture(prev_level_flow_tex);
 841                 return final_tex;
 842         }
 843 }
 844
 845 Splat::Splat(const OperatingPoint &op)
 846         : op(op)
 847 {
 848         splat_vs_obj = compile_shader(read_file("splat.vert"), GL_VERTEX_SHADER);
 849         splat_fs_obj = compile_shader(read_file("splat.frag"), GL_FRAGMENT_SHADER);
 850         splat_program = link_program(splat_vs_obj, splat_fs_obj);
 851
 852         uniform_splat_size = glGetUniformLocation(splat_program, "splat_size");
 853         uniform_alpha = glGetUniformLocation(splat_program, "alpha");
 854         uniform_image_tex = glGetUniformLocation(splat_program, "image_tex");
 855         uniform_flow_tex = glGetUniformLocation(splat_program, "flow_tex");
 856         uniform_inv_flow_size = glGetUniformLocation(splat_program, "inv_flow_size");
 857 }
 858
 859 void Splat::exec(GLuint image_tex, GLuint bidirectional_flow_tex, GLuint flow_tex, GLuint depth_rb, int width, int height, float alpha)
 860 {
 861         glUseProgram(splat_program);
 862
 863         bind_sampler(splat_program, uniform_image_tex, 0, image_tex, linear_sampler);
 864         bind_sampler(splat_program, uniform_flow_tex, 1, bidirectional_flow_tex, nearest_sampler);
 865
 866         glProgramUniform2f(splat_program, uniform_splat_size, op.splat_size / width, op.splat_size / height);
 867         glProgramUniform1f(splat_program, uniform_alpha, alpha);
 868         glProgramUniform2f(splat_program, uniform_inv_flow_size, 1.0f / width, 1.0f / height);
 869
 870         glViewport(0, 0, width, height);
 871         glDisable(GL_BLEND);
 872         glEnable(GL_DEPTH_TEST);
 873         glDepthFunc(GL_LESS);  // We store the difference between I_0 and I_1, where less difference is good. (Default 1.0 is effectively +inf, which always loses.)
 874
 875         fbos.render_to(depth_rb, flow_tex);
 876
 877         // Evidently NVIDIA doesn't use fast clears for glClearTexImage, so clear now that
 878         // we've got it bound.
 879         glClearColor(1000.0f, 1000.0f, 0.0f, 1.0f);  // Invalid flow.
 880         glClearDepth(1.0f);  // Effectively infinity.
 881         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 882
 883         glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width * height * 2);
 884
 885         glDisable(GL_DEPTH_TEST);
 886 }
 887
 888 HoleFill::HoleFill()
 889 {
 890         fill_vs_obj = compile_shader(read_file("hole_fill.vert"), GL_VERTEX_SHADER);
 891         fill_fs_obj = compile_shader(read_file("hole_fill.frag"), GL_FRAGMENT_SHADER);
 892         fill_program = link_program(fill_vs_obj, fill_fs_obj);
 893
 894         uniform_tex = glGetUniformLocation(fill_program, "tex");
 895         uniform_z = glGetUniformLocation(fill_program, "z");
 896         uniform_sample_offset = glGetUniformLocation(fill_program, "sample_offset");
 897 }
 898
 899 void HoleFill::exec(GLuint flow_tex, GLuint depth_rb, GLuint temp_tex[3], int width, int height)
 900 {
 901         glUseProgram(fill_program);
 902
 903         bind_sampler(fill_program, uniform_tex, 0, flow_tex, nearest_sampler);
 904
 905         glProgramUniform1f(fill_program, uniform_z, 1.0f - 1.0f / 1024.0f);
 906
 907         glViewport(0, 0, width, height);
 908         glDisable(GL_BLEND);
 909         glEnable(GL_DEPTH_TEST);
 910         glDepthFunc(GL_LESS);  // Only update the values > 0.999f (ie., only invalid pixels).
 911
 912         fbos.render_to(depth_rb, flow_tex);  // NOTE: Reading and writing to the same texture.
 913
 914         // Fill holes from the left, by shifting 1, 2, 4, 8, etc. pixels to the right.
 915         for (int offs = 1; offs < width; offs *= 2) {
 916                 glProgramUniform2f(fill_program, uniform_sample_offset, -offs / float(width), 0.0f);
 917                 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
 918                 glTextureBarrier();
 919         }
 920         glCopyImageSubData(flow_tex, GL_TEXTURE_2D, 0, 0, 0, 0, temp_tex[0], GL_TEXTURE_2D, 0, 0, 0, 0, width, height, 1);
 921
 922         // Similar to the right; adjust Z a bit down, so that we re-fill the pixels that
 923         // were overwritten in the last algorithm.
 924         glProgramUniform1f(fill_program, uniform_z, 1.0f - 2.0f / 1024.0f);
 925         for (int offs = 1; offs < width; offs *= 2) {
 926                 glProgramUniform2f(fill_program, uniform_sample_offset, offs / float(width), 0.0f);
 927                 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
 928                 glTextureBarrier();
 929         }
 930         glCopyImageSubData(flow_tex, GL_TEXTURE_2D, 0, 0, 0, 0, temp_tex[1], GL_TEXTURE_2D, 0, 0, 0, 0, width, height, 1);
 931
 932         // Up.
 933         glProgramUniform1f(fill_program, uniform_z, 1.0f - 3.0f / 1024.0f);
 934         for (int offs = 1; offs < height; offs *= 2) {
 935                 glProgramUniform2f(fill_program, uniform_sample_offset, 0.0f, -offs / float(height));
 936                 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
 937                 glTextureBarrier();
 938         }
 939         glCopyImageSubData(flow_tex, GL_TEXTURE_2D, 0, 0, 0, 0, temp_tex[2], GL_TEXTURE_2D, 0, 0, 0, 0, width, height, 1);
 940
 941         // Down.
 942         glProgramUniform1f(fill_program, uniform_z, 1.0f - 4.0f / 1024.0f);
 943         for (int offs = 1; offs < height; offs *= 2) {
 944                 glProgramUniform2f(fill_program, uniform_sample_offset, 0.0f, offs / float(height));
 945                 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
 946                 glTextureBarrier();
 947         }
 948
 949         glDisable(GL_DEPTH_TEST);
 950 }
 951
 952 HoleBlend::HoleBlend()
 953 {
 954         blend_vs_obj = compile_shader(read_file("hole_fill.vert"), GL_VERTEX_SHADER);  // Reuse the vertex shader from the fill.
 955         blend_fs_obj = compile_shader(read_file("hole_blend.frag"), GL_FRAGMENT_SHADER);
 956         blend_program = link_program(blend_vs_obj, blend_fs_obj);
 957
 958         uniform_left_tex = glGetUniformLocation(blend_program, "left_tex");
 959         uniform_right_tex = glGetUniformLocation(blend_program, "right_tex");
 960         uniform_up_tex = glGetUniformLocation(blend_program, "up_tex");
 961         uniform_down_tex = glGetUniformLocation(blend_program, "down_tex");
 962         uniform_z = glGetUniformLocation(blend_program, "z");
 963         uniform_sample_offset = glGetUniformLocation(blend_program, "sample_offset");
 964 }
 965
 966 void HoleBlend::exec(GLuint flow_tex, GLuint depth_rb, GLuint temp_tex[3], int width, int height)
 967 {
 968         glUseProgram(blend_program);
 969
 970         bind_sampler(blend_program, uniform_left_tex, 0, temp_tex[0], nearest_sampler);
 971         bind_sampler(blend_program, uniform_right_tex, 1, temp_tex[1], nearest_sampler);
 972         bind_sampler(blend_program, uniform_up_tex, 2, temp_tex[2], nearest_sampler);
 973         bind_sampler(blend_program, uniform_down_tex, 3, flow_tex, nearest_sampler);
 974
 975         glProgramUniform1f(blend_program, uniform_z, 1.0f - 4.0f / 1024.0f);
 976         glProgramUniform2f(blend_program, uniform_sample_offset, 0.0f, 0.0f);
 977
 978         glViewport(0, 0, width, height);
 979         glDisable(GL_BLEND);
 980         glEnable(GL_DEPTH_TEST);
 981         glDepthFunc(GL_LEQUAL);  // Skip over all of the pixels that were never holes to begin with.
 982
 983         fbos.render_to(depth_rb, flow_tex);  // NOTE: Reading and writing to the same texture.
 984
 985         glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
 986
 987         glDisable(GL_DEPTH_TEST);
 988 }
 989
 990 Blend::Blend()
 991 {
 992         blend_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
 993         blend_fs_obj = compile_shader(read_file("blend.frag"), GL_FRAGMENT_SHADER);
 994         blend_program = link_program(blend_vs_obj, blend_fs_obj);
 995
 996         uniform_image_tex = glGetUniformLocation(blend_program, "image_tex");
 997         uniform_flow_tex = glGetUniformLocation(blend_program, "flow_tex");
 998         uniform_alpha = glGetUniformLocation(blend_program, "alpha");
 999         uniform_flow_consistency_tolerance = glGetUniformLocation(blend_program, "flow_consistency_tolerance");
1000 }
1001
1002 void Blend::exec(GLuint image_tex, GLuint flow_tex, GLuint output_tex, int level_width, int level_height, float alpha)
1003 {
1004         glUseProgram(blend_program);
1005         bind_sampler(blend_program, uniform_image_tex, 0, image_tex, linear_sampler);
1006         bind_sampler(blend_program, uniform_flow_tex, 1, flow_tex, linear_sampler);  // May be upsampled.
1007         glProgramUniform1f(blend_program, uniform_alpha, alpha);
1008
1009         glViewport(0, 0, level_width, level_height);
1010         fbos.render_to(output_tex);
1011         glDisable(GL_BLEND);  // A bit ironic, perhaps.
1012         glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
1013 }
1014
1015 Interpolate::Interpolate(int width, int height, const OperatingPoint &op)
1016         : width(width), height(height), flow_level(op.finest_level), op(op), splat(op) {
1017         // Set up the vertex data that will be shared between all passes.
1018         float vertices[] = {
1019                 0.0f, 1.0f,
1020                 0.0f, 0.0f,
1021                 1.0f, 1.0f,
1022                 1.0f, 0.0f,
1023         };
1024         glCreateBuffers(1, &vertex_vbo);
1025         glNamedBufferData(vertex_vbo, sizeof(vertices), vertices, GL_STATIC_DRAW);
1026
1027         glCreateVertexArrays(1, &vao);
1028         glBindVertexArray(vao);
1029         glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
1030
1031         GLint position_attrib = 0;  // Hard-coded in every vertex shader.
1032         glEnableVertexArrayAttrib(vao, position_attrib);
1033         glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
1034 }
1035
1036 GLuint Interpolate::exec(GLuint image_tex, GLuint bidirectional_flow_tex, GLuint width, GLuint height, float alpha)
1037 {
1038         GPUTimers timers;
1039
1040         ScopedTimer total_timer("Interpolate", &timers);
1041
1042         glBindVertexArray(vao);
1043
1044         // Pick out the right level to test splatting results on.
1045         GLuint tex_view;
1046         glGenTextures(1, &tex_view);
1047         glTextureView(tex_view, GL_TEXTURE_2D_ARRAY, image_tex, GL_RGBA8, flow_level, 1, 0, 2);
1048
1049         int flow_width = width >> flow_level;
1050         int flow_height = height >> flow_level;
1051
1052         GLuint flow_tex = pool.get_texture(GL_RG16F, flow_width, flow_height);
1053         GLuint depth_rb = pool.get_renderbuffer(GL_DEPTH_COMPONENT16, flow_width, flow_height);  // Used for ranking flows.
1054
1055         {
1056                 ScopedTimer timer("Splat", &total_timer);
1057                 splat.exec(tex_view, bidirectional_flow_tex, flow_tex, depth_rb, flow_width, flow_height, alpha);
1058         }
1059         glDeleteTextures(1, &tex_view);
1060
1061         GLuint temp_tex[3];
1062         temp_tex[0] = pool.get_texture(GL_RG16F, flow_width, flow_height);
1063         temp_tex[1] = pool.get_texture(GL_RG16F, flow_width, flow_height);
1064         temp_tex[2] = pool.get_texture(GL_RG16F, flow_width, flow_height);
1065
1066         {
1067                 ScopedTimer timer("Fill holes", &total_timer);
1068                 hole_fill.exec(flow_tex, depth_rb, temp_tex, flow_width, flow_height);
1069                 hole_blend.exec(flow_tex, depth_rb, temp_tex, flow_width, flow_height);
1070         }
1071
1072         pool.release_texture(temp_tex[0]);
1073         pool.release_texture(temp_tex[1]);
1074         pool.release_texture(temp_tex[2]);
1075         pool.release_renderbuffer(depth_rb);
1076
1077         GLuint output_tex = pool.get_texture(GL_RGBA8, width, height);
1078         {
1079                 ScopedTimer timer("Blend", &total_timer);
1080                 blend.exec(image_tex, flow_tex, output_tex, width, height, alpha);
1081         }
1082         pool.release_texture(flow_tex);
1083         total_timer.end();
1084         if (!in_warmup) {
1085                 timers.print();
1086         }
1087
1088         return output_tex;
1089 }
1090
1091 GLuint TexturePool::get_texture(GLenum format, GLuint width, GLuint height, GLuint num_layers)
1092 {
1093         for (Texture &tex : textures) {
1094                 if (!tex.in_use && !tex.is_renderbuffer && tex.format == format &&
1095                     tex.width == width && tex.height == height && tex.num_layers == num_layers) {
1096                         tex.in_use = true;
1097                         return tex.tex_num;
1098                 }
1099         }
1100
1101         Texture tex;
1102         if (num_layers == 0) {
1103                 glCreateTextures(GL_TEXTURE_2D, 1, &tex.tex_num);
1104                 glTextureStorage2D(tex.tex_num, 1, format, width, height);
1105         } else {
1106                 glCreateTextures(GL_TEXTURE_2D_ARRAY, 1, &tex.tex_num);
1107                 glTextureStorage3D(tex.tex_num, 1, format, width, height, num_layers);
1108         }
1109         tex.format = format;
1110         tex.width = width;
1111         tex.height = height;
1112         tex.num_layers = num_layers;
1113         tex.in_use = true;
1114         tex.is_renderbuffer = false;
1115         textures.push_back(tex);
1116         return tex.tex_num;
1117 }
1118
1119 GLuint TexturePool::get_renderbuffer(GLenum format, GLuint width, GLuint height)
1120 {
1121         for (Texture &tex : textures) {
1122                 if (!tex.in_use && tex.is_renderbuffer && tex.format == format &&
1123                     tex.width == width && tex.height == height) {
1124                         tex.in_use = true;
1125                         return tex.tex_num;
1126                 }
1127         }
1128
1129         Texture tex;
1130         glCreateRenderbuffers(1, &tex.tex_num);
1131         glNamedRenderbufferStorage(tex.tex_num, format, width, height);
1132
1133         tex.format = format;
1134         tex.width = width;
1135         tex.height = height;
1136         tex.in_use = true;
1137         tex.is_renderbuffer = true;
1138         textures.push_back(tex);
1139         return tex.tex_num;
1140 }
1141
1142 void TexturePool::release_texture(GLuint tex_num)
1143 {
1144         for (Texture &tex : textures) {
1145                 if (!tex.is_renderbuffer && tex.tex_num == tex_num) {
1146                         assert(tex.in_use);
1147                         tex.in_use = false;
1148                         return;
1149                 }
1150         }
1151         assert(false);
1152 }
1153
1154 void TexturePool::release_renderbuffer(GLuint tex_num)
1155 {
1156         for (Texture &tex : textures) {
1157                 if (tex.is_renderbuffer && tex.tex_num == tex_num) {
1158                         assert(tex.in_use);
1159                         tex.in_use = false;
1160                         return;
1161                 }
1162         }
1163         //assert(false);
1164 }
1165
1166 // OpenGL uses a bottom-left coordinate system, .flo files use a top-left coordinate system.
1167 void flip_coordinate_system(float *dense_flow, unsigned width, unsigned height)
1168 {
1169         for (unsigned i = 0; i < width * height; ++i) {
1170                 dense_flow[i * 2 + 1] = -dense_flow[i * 2 + 1];
1171         }
1172 }
1173
1174 // Not relevant for RGB.
1175 void flip_coordinate_system(uint8_t *dense_flow, unsigned width, unsigned height)
1176 {
1177 }
1178
1179 void write_flow(const char *filename, const float *dense_flow, unsigned width, unsigned height)
1180 {
1181         FILE *flowfp = fopen(filename, "wb");
1182         fprintf(flowfp, "FEIH");
1183         fwrite(&width, 4, 1, flowfp);
1184         fwrite(&height, 4, 1, flowfp);
1185         for (unsigned y = 0; y < height; ++y) {
1186                 int yy = height - y - 1;
1187                 fwrite(&dense_flow[yy * width * 2], width * 2 * sizeof(float), 1, flowfp);
1188         }
1189         fclose(flowfp);
1190 }
1191
1192 // Not relevant for RGB.
1193 void write_flow(const char *filename, const uint8_t *dense_flow, unsigned width, unsigned height)
1194 {
1195         assert(false);
1196 }
1197
1198 void write_ppm(const char *filename, const float *dense_flow, unsigned width, unsigned height)
1199 {
1200         FILE *fp = fopen(filename, "wb");
1201         fprintf(fp, "P6\n%d %d\n255\n", width, height);
1202         for (unsigned y = 0; y < unsigned(height); ++y) {
1203                 int yy = height - y - 1;
1204                 for (unsigned x = 0; x < unsigned(width); ++x) {
1205                         float du = dense_flow[(yy * width + x) * 2 + 0];
1206                         float dv = dense_flow[(yy * width + x) * 2 + 1];
1207
1208                         uint8_t r, g, b;
1209                         flow2rgb(du, dv, &r, &g, &b);
1210                         putc(r, fp);
1211                         putc(g, fp);
1212                         putc(b, fp);
1213                 }
1214         }
1215         fclose(fp);
1216 }
1217
1218 void write_ppm(const char *filename, const uint8_t *rgba, unsigned width, unsigned height)
1219 {
1220         unique_ptr<uint8_t[]> rgb_line(new uint8_t[width * 3 + 1]);
1221
1222         FILE *fp = fopen(filename, "wb");
1223         fprintf(fp, "P6\n%d %d\n255\n", width, height);
1224         for (unsigned y = 0; y < height; ++y) {
1225                 unsigned y2 = height - 1 - y;
1226                 for (size_t x = 0; x < width; ++x) {
1227                         memcpy(&rgb_line[x * 3], &rgba[(y2 * width + x) * 4], 4);
1228                 }
1229                 fwrite(rgb_line.get(), width * 3, 1, fp);
1230         }
1231         fclose(fp);
1232 }
1233
1234 struct FlowType {
1235         using type = float;
1236         static constexpr GLenum gl_format = GL_RG;
1237         static constexpr GLenum gl_type = GL_FLOAT;
1238         static constexpr int num_channels = 2;
1239 };
1240
1241 struct RGBAType {
1242         using type = uint8_t;
1243         static constexpr GLenum gl_format = GL_RGBA;
1244         static constexpr GLenum gl_type = GL_UNSIGNED_BYTE;
1245         static constexpr int num_channels = 4;
1246 };
1247
1248 template <class Type>
1249 void finish_one_read(GLuint width, GLuint height)
1250 {
1251         using T = typename Type::type;
1252         constexpr int bytes_per_pixel = Type::num_channels * sizeof(T);
1253
1254         assert(!reads_in_progress.empty());
1255         ReadInProgress read = reads_in_progress.front();
1256         reads_in_progress.pop_front();
1257
1258         unique_ptr<T[]> flow(new typename Type::type[width * height * Type::num_channels]);
1259         void *buf = glMapNamedBufferRange(read.pbo, 0, width * height * bytes_per_pixel, GL_MAP_READ_BIT);  // Blocks if the read isn't done yet.
1260         memcpy(flow.get(), buf, width * height * bytes_per_pixel);  // TODO: Unneeded for RGBType, since flip_coordinate_system() does nothing.:
1261         glUnmapNamedBuffer(read.pbo);
1262         spare_pbos.push(read.pbo);
1263
1264         flip_coordinate_system(flow.get(), width, height);
1265         if (!read.flow_filename.empty()) {
1266                 write_flow(read.flow_filename.c_str(), flow.get(), width, height);
1267                 fprintf(stderr, "%s %s -> %s\n", read.filename0.c_str(), read.filename1.c_str(), read.flow_filename.c_str());
1268         }
1269         if (!read.ppm_filename.empty()) {
1270                 write_ppm(read.ppm_filename.c_str(), flow.get(), width, height);
1271         }
1272 }
1273
1274 template <class Type>
1275 void schedule_read(GLuint tex, GLuint width, GLuint height, const char *filename0, const char *filename1, const char *flow_filename, const char *ppm_filename)
1276 {
1277         using T = typename Type::type;
1278         constexpr int bytes_per_pixel = Type::num_channels * sizeof(T);
1279
1280         if (spare_pbos.empty()) {
1281                 finish_one_read<Type>(width, height);
1282         }
1283         assert(!spare_pbos.empty());
1284         reads_in_progress.emplace_back(ReadInProgress{ spare_pbos.top(), filename0, filename1, flow_filename, ppm_filename });
1285         glBindBuffer(GL_PIXEL_PACK_BUFFER, spare_pbos.top());
1286         spare_pbos.pop();
1287         glGetTextureImage(tex, 0, Type::gl_format, Type::gl_type, width * height * bytes_per_pixel, nullptr);
1288         glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
1289 }
1290
1291 void compute_flow_only(int argc, char **argv, int optind)
1292 {
1293         const char *filename0 = argc >= (optind + 1) ? argv[optind] : "test1499.png";
1294         const char *filename1 = argc >= (optind + 2) ? argv[optind + 1] : "test1500.png";
1295         const char *flow_filename = argc >= (optind + 3) ? argv[optind + 2] : "flow.flo";
1296
1297         // Load pictures.
1298         unsigned width1, height1, width2, height2;
1299         GLuint tex0 = load_texture(filename0, &width1, &height1, WITHOUT_MIPMAPS);
1300         GLuint tex1 = load_texture(filename1, &width2, &height2, WITHOUT_MIPMAPS);
1301
1302         if (width1 != width2 || height1 != height2) {
1303                 fprintf(stderr, "Image dimensions don't match (%dx%d versus %dx%d)\n",
1304                         width1, height1, width2, height2);
1305                 exit(1);
1306         }
1307
1308         // Move them into an array texture, since that's how the rest of the code
1309         // would like them.
1310         GLuint image_tex;
1311         glCreateTextures(GL_TEXTURE_2D_ARRAY, 1, &image_tex);
1312         glTextureStorage3D(image_tex, 1, GL_RGBA8, width1, height1, 2);
1313         glCopyImageSubData(tex0, GL_TEXTURE_2D, 0, 0, 0, 0, image_tex, GL_TEXTURE_2D_ARRAY, 0, 0, 0, 0, width1, height1, 1);
1314         glCopyImageSubData(tex1, GL_TEXTURE_2D, 0, 0, 0, 0, image_tex, GL_TEXTURE_2D_ARRAY, 0, 0, 0, 1, width1, height1, 1);
1315         glDeleteTextures(1, &tex0);
1316         glDeleteTextures(1, &tex1);
1317
1318         // Set up some PBOs to do asynchronous readback.
1319         GLuint pbos[5];
1320         glCreateBuffers(5, pbos);
1321         for (int i = 0; i < 5; ++i) {
1322                 glNamedBufferData(pbos[i], width1 * height1 * 2 * 2 * sizeof(float), nullptr, GL_STREAM_READ);
1323                 spare_pbos.push(pbos[i]);
1324         }
1325
1326         int levels = find_num_levels(width1, height1);
1327
1328         GLuint tex_gray;
1329         glCreateTextures(GL_TEXTURE_2D_ARRAY, 1, &tex_gray);
1330         glTextureStorage3D(tex_gray, levels, GL_R8, width1, height1, 2);
1331
1332         GrayscaleConversion gray;
1333         gray.exec(image_tex, tex_gray, width1, height1, /*num_layers=*/2);
1334         glGenerateTextureMipmap(tex_gray);
1335
1336         OperatingPoint op = operating_point3;
1337         if (!enable_variational_refinement) {
1338                 op.variational_refinement = false;
1339         }
1340         DISComputeFlow compute_flow(width1, height1, op);
1341
1342         if (enable_warmup) {
1343                 in_warmup = true;
1344                 for (int i = 0; i < 10; ++i) {
1345                         GLuint final_tex = compute_flow.exec(tex_gray, DISComputeFlow::FORWARD, DISComputeFlow::RESIZE_FLOW_TO_FULL_SIZE);
1346                         compute_flow.release_texture(final_tex);
1347                 }
1348                 in_warmup = false;
1349         }
1350
1351         GLuint final_tex = compute_flow.exec(tex_gray, DISComputeFlow::FORWARD, DISComputeFlow::RESIZE_FLOW_TO_FULL_SIZE);
1352         //GLuint final_tex = compute_flow.exec(tex_gray, DISComputeFlow::FORWARD_AND_BACKWARD, DISComputeFlow::RESIZE_FLOW_TO_FULL_SIZE);
1353
1354         schedule_read<FlowType>(final_tex, width1, height1, filename0, filename1, flow_filename, "flow.ppm");
1355         compute_flow.release_texture(final_tex);
1356
1357         // See if there are more flows on the command line (ie., more than three arguments),
1358         // and if so, process them.
1359         int num_flows = (argc - optind) / 3;
1360         for (int i = 1; i < num_flows; ++i) {
1361                 const char *filename0 = argv[optind + i * 3 + 0];
1362                 const char *filename1 = argv[optind + i * 3 + 1];
1363                 const char *flow_filename = argv[optind + i * 3 + 2];
1364                 GLuint width, height;
1365                 GLuint tex0 = load_texture(filename0, &width, &height, WITHOUT_MIPMAPS);
1366                 if (width != width1 || height != height1) {
1367                         fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n",
1368                                 filename0, width, height, width1, height1);
1369                         exit(1);
1370                 }
1371                 glCopyImageSubData(tex0, GL_TEXTURE_2D, 0, 0, 0, 0, image_tex, GL_TEXTURE_2D_ARRAY, 0, 0, 0, 0, width1, height1, 1);
1372                 glDeleteTextures(1, &tex0);
1373
1374                 GLuint tex1 = load_texture(filename1, &width, &height, WITHOUT_MIPMAPS);
1375                 if (width != width1 || height != height1) {
1376                         fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n",
1377                                 filename1, width, height, width1, height1);
1378                         exit(1);
1379                 }
1380                 glCopyImageSubData(tex1, GL_TEXTURE_2D, 0, 0, 0, 0, image_tex, GL_TEXTURE_2D_ARRAY, 0, 0, 0, 1, width1, height1, 1);
1381                 glDeleteTextures(1, &tex1);
1382
1383                 gray.exec(image_tex, tex_gray, width1, height1, /*num_layers=*/2);
1384                 glGenerateTextureMipmap(tex_gray);
1385
1386                 GLuint final_tex = compute_flow.exec(tex_gray, DISComputeFlow::FORWARD, DISComputeFlow::RESIZE_FLOW_TO_FULL_SIZE);
1387
1388                 schedule_read<FlowType>(final_tex, width1, height1, filename0, filename1, flow_filename, "");
1389                 compute_flow.release_texture(final_tex);
1390         }
1391         glDeleteTextures(1, &tex_gray);
1392
1393         while (!reads_in_progress.empty()) {
1394                 finish_one_read<FlowType>(width1, height1);
1395         }
1396 }
1397
1398 // Interpolate images based on
1399 //
1400 //   Herbst, Seitz, Baker: “Occlusion Reasoning for Temporal Interpolation
1401 //   Using Optical Flow”
1402 //
1403 // or at least a reasonable subset thereof. Unfinished.
1404 void interpolate_image(int argc, char **argv, int optind)
1405 {
1406         const char *filename0 = argc >= (optind + 1) ? argv[optind] : "test1499.png";
1407         const char *filename1 = argc >= (optind + 2) ? argv[optind + 1] : "test1500.png";
1408         //const char *out_filename = argc >= (optind + 3) ? argv[optind + 2] : "interpolated.png";
1409
1410         // Load pictures.
1411         unsigned width1, height1, width2, height2;
1412         GLuint tex0 = load_texture(filename0, &width1, &height1, WITH_MIPMAPS);
1413         GLuint tex1 = load_texture(filename1, &width2, &height2, WITH_MIPMAPS);
1414
1415         if (width1 != width2 || height1 != height2) {
1416                 fprintf(stderr, "Image dimensions don't match (%dx%d versus %dx%d)\n",
1417                         width1, height1, width2, height2);
1418                 exit(1);
1419         }
1420
1421         // Move them into an array texture, since that's how the rest of the code
1422         // would like them.
1423         int levels = find_num_levels(width1, height1);
1424         GLuint image_tex;
1425         glCreateTextures(GL_TEXTURE_2D_ARRAY, 1, &image_tex);
1426         glTextureStorage3D(image_tex, levels, GL_RGBA8, width1, height1, 2);
1427         glCopyImageSubData(tex0, GL_TEXTURE_2D, 0, 0, 0, 0, image_tex, GL_TEXTURE_2D_ARRAY, 0, 0, 0, 0, width1, height1, 1);
1428         glCopyImageSubData(tex1, GL_TEXTURE_2D, 0, 0, 0, 0, image_tex, GL_TEXTURE_2D_ARRAY, 0, 0, 0, 1, width1, height1, 1);
1429         glDeleteTextures(1, &tex0);
1430         glDeleteTextures(1, &tex1);
1431         glGenerateTextureMipmap(image_tex);
1432
1433         // Set up some PBOs to do asynchronous readback.
1434         GLuint pbos[5];
1435         glCreateBuffers(5, pbos);
1436         for (int i = 0; i < 5; ++i) {
1437                 glNamedBufferData(pbos[i], width1 * height1 * 4 * sizeof(uint8_t), nullptr, GL_STREAM_READ);
1438                 spare_pbos.push(pbos[i]);
1439         }
1440
1441         OperatingPoint op = operating_point3;
1442         if (!enable_variational_refinement) {
1443                 op.variational_refinement = false;
1444         }
1445         DISComputeFlow compute_flow(width1, height1, op);
1446         GrayscaleConversion gray;
1447         Interpolate interpolate(width1, height1, op);
1448
1449         GLuint tex_gray;
1450         glCreateTextures(GL_TEXTURE_2D_ARRAY, 1, &tex_gray);
1451         glTextureStorage3D(tex_gray, levels, GL_R8, width1, height1, 2);
1452         gray.exec(image_tex, tex_gray, width1, height1, /*num_layers=*/2);
1453         glGenerateTextureMipmap(tex_gray);
1454
1455         if (enable_warmup) {
1456                 in_warmup = true;
1457                 for (int i = 0; i < 10; ++i) {
1458                         GLuint bidirectional_flow_tex = compute_flow.exec(tex_gray, DISComputeFlow::FORWARD_AND_BACKWARD, DISComputeFlow::DO_NOT_RESIZE_FLOW);
1459                         GLuint interpolated_tex = interpolate.exec(image_tex, bidirectional_flow_tex, width1, height1, 0.5f);
1460                         compute_flow.release_texture(bidirectional_flow_tex);
1461                         interpolate.release_texture(interpolated_tex);
1462                 }
1463                 in_warmup = false;
1464         }
1465
1466         GLuint bidirectional_flow_tex = compute_flow.exec(tex_gray, DISComputeFlow::FORWARD_AND_BACKWARD, DISComputeFlow::DO_NOT_RESIZE_FLOW);
1467
1468         for (int frameno = 1; frameno < 60; ++frameno) {
1469                 char ppm_filename[256];
1470                 snprintf(ppm_filename, sizeof(ppm_filename), "interp%04d.ppm", frameno);
1471
1472                 float alpha = frameno / 60.0f;
1473                 GLuint interpolated_tex = interpolate.exec(image_tex, bidirectional_flow_tex, width1, height1, alpha);
1474
1475                 schedule_read<RGBAType>(interpolated_tex, width1, height1, filename0, filename1, "", ppm_filename);
1476                 interpolate.release_texture(interpolated_tex);
1477         }
1478
1479         while (!reads_in_progress.empty()) {
1480                 finish_one_read<RGBAType>(width1, height1);
1481         }
1482 }
1483
1484 int main(int argc, char **argv)
1485 {
1486         static const option long_options[] = {
1487                 { "smoothness-relative-weight", required_argument, 0, 's' },  // alpha.
1488                 { "intensity-relative-weight", required_argument, 0, 'i' },  // delta.
1489                 { "gradient-relative-weight", required_argument, 0, 'g' },  // gamma.
1490                 { "disable-timing", no_argument, 0, 1000 },
1491                 { "detailed-timing", no_argument, 0, 1003 },
1492                 { "ignore-variational-refinement", no_argument, 0, 1001 },  // Still calculates it, just doesn't apply it.
1493                 { "interpolate", no_argument, 0, 1002 },
1494                 { "warmup", no_argument, 0, 1004 }
1495         };
1496
1497         for ( ;; ) {
1498                 int option_index = 0;
1499                 int c = getopt_long(argc, argv, "s:i:g:", long_options, &option_index);
1500
1501                 if (c == -1) {
1502                         break;
1503                 }
1504                 switch (c) {
1505                 case 's':
1506                         vr_alpha = atof(optarg);
1507                         break;
1508                 case 'i':
1509                         vr_delta = atof(optarg);
1510                         break;
1511                 case 'g':
1512                         vr_gamma = atof(optarg);
1513                         break;
1514                 case 1000:
1515                         enable_timing = false;
1516                         break;
1517                 case 1001:
1518                         enable_variational_refinement = false;
1519                         break;
1520                 case 1002:
1521                         enable_interpolation = true;
1522                         break;
1523                 case 1003:
1524                         detailed_timing = true;
1525                         break;
1526                 case 1004:
1527                         enable_warmup = true;
1528                         break;
1529                 default:
1530                         fprintf(stderr, "Unknown option '%s'\n", argv[option_index]);
1531                         exit(1);
1532                 };
1533         }
1534
1535         if (SDL_Init(SDL_INIT_EVERYTHING) == -1) {
1536                 fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError());
1537                 exit(1);
1538         }
1539         SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
1540         SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0);
1541         SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0);
1542         SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
1543
1544         SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
1545         SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
1546         SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 5);
1547         // SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
1548         window = SDL_CreateWindow("OpenGL window",
1549                 SDL_WINDOWPOS_UNDEFINED,
1550                 SDL_WINDOWPOS_UNDEFINED,
1551                 64, 64,
1552                 SDL_WINDOW_OPENGL | SDL_WINDOW_HIDDEN);
1553         SDL_GLContext context = SDL_GL_CreateContext(window);
1554         assert(context != nullptr);
1555
1556         glDisable(GL_DITHER);
1557
1558         // FIXME: Should be part of DISComputeFlow (but needs to be initialized
1559         // before all the render passes).
1560         float vertices[] = {
1561                 0.0f, 1.0f,
1562                 0.0f, 0.0f,
1563                 1.0f, 1.0f,
1564                 1.0f, 0.0f,
1565         };
1566         glCreateBuffers(1, &vertex_vbo);
1567         glNamedBufferData(vertex_vbo, sizeof(vertices), vertices, GL_STATIC_DRAW);
1568         glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
1569
1570         if (enable_interpolation) {
1571                 interpolate_image(argc, argv, optind);
1572         } else {
1573                 compute_flow_only(argc, argv, optind);
1574         }
1575 }