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>
27 #define BUFFER_OFFSET(i) ((char *)nullptr + (i))
31 // Operating point 3 (10 Hz on CPU, excluding preprocessing).
32 constexpr float patch_overlap_ratio = 0.75f;
33 constexpr unsigned coarsest_level = 5;
34 constexpr unsigned finest_level = 1;
35 constexpr unsigned patch_size_pixels = 12;
37 // Weighting constants for the different parts of the variational refinement.
38 // These don't correspond 1:1 to the values given in the DIS paper,
39 // since we have different normalizations and ranges in some cases.
40 // These are found through a simple grid search on some MPI-Sintel data,
41 // although the error (EPE) seems to be fairly insensitive to the precise values.
42 // Only the relative values matter, so we fix alpha (the smoothness constant)
43 // at unity and tweak the others.
44 float vr_alpha = 1.0f, vr_delta = 0.25f, vr_gamma = 0.25f;
46 bool enable_timing = true;
47 bool enable_variational_refinement = true; // Just for debugging.
49 // Some global OpenGL objects.
50 // TODO: These should really be part of DISComputeFlow.
51 GLuint nearest_sampler, linear_sampler, zero_border_sampler;
54 // Structures for asynchronous readback. We assume everything is the same size (and GL_RG16F).
55 struct ReadInProgress {
57 string filename0, filename1;
58 string flow_filename, ppm_filename; // Either may be empty for no write.
60 stack<GLuint> spare_pbos;
61 deque<ReadInProgress> reads_in_progress;
63 string read_file(const string &filename)
65 FILE *fp = fopen(filename.c_str(), "r");
67 perror(filename.c_str());
71 int ret = fseek(fp, 0, SEEK_END);
73 perror("fseek(SEEK_END)");
79 ret = fseek(fp, 0, SEEK_SET);
81 perror("fseek(SEEK_SET)");
87 ret = fread(&str[0], size, 1, fp);
93 fprintf(stderr, "Short read when trying to read %d bytes from %s\n",
94 size, filename.c_str());
103 GLuint compile_shader(const string &shader_src, GLenum type)
105 GLuint obj = glCreateShader(type);
106 const GLchar* source[] = { shader_src.data() };
107 const GLint length[] = { (GLint)shader_src.size() };
108 glShaderSource(obj, 1, source, length);
109 glCompileShader(obj);
111 GLchar info_log[4096];
112 GLsizei log_length = sizeof(info_log) - 1;
113 glGetShaderInfoLog(obj, log_length, &log_length, info_log);
114 info_log[log_length] = 0;
115 if (strlen(info_log) > 0) {
116 fprintf(stderr, "Shader compile log: %s\n", info_log);
120 glGetShaderiv(obj, GL_COMPILE_STATUS, &status);
121 if (status == GL_FALSE) {
122 // Add some line numbers to easier identify compile errors.
123 string src_with_lines = "/* 1 */ ";
125 for (char ch : shader_src) {
126 src_with_lines.push_back(ch);
129 snprintf(buf, sizeof(buf), "/* %3zu */ ", ++lineno);
130 src_with_lines += buf;
134 fprintf(stderr, "Failed to compile shader:\n%s\n", src_with_lines.c_str());
141 GLuint load_texture(const char *filename, unsigned *width_ret, unsigned *height_ret)
143 SDL_Surface *surf = IMG_Load(filename);
144 if (surf == nullptr) {
145 fprintf(stderr, "IMG_Load(%s): %s\n", filename, IMG_GetError());
149 // For whatever reason, SDL doesn't support converting to YUV surfaces
150 // nor grayscale, so we'll do it (slowly) ourselves.
151 SDL_Surface *rgb_surf = SDL_ConvertSurfaceFormat(surf, SDL_PIXELFORMAT_RGBA8888, /*flags=*/0);
152 if (rgb_surf == nullptr) {
153 fprintf(stderr, "SDL_ConvertSurfaceFormat(%s): %s\n", filename, SDL_GetError());
157 SDL_FreeSurface(surf);
159 unsigned width = rgb_surf->w, height = rgb_surf->h;
160 const uint8_t *sptr = (uint8_t *)rgb_surf->pixels;
161 unique_ptr<uint8_t[]> pix(new uint8_t[width * height]);
163 // Extract the Y component, and convert to bottom-left origin.
164 for (unsigned y = 0; y < height; ++y) {
165 unsigned y2 = height - 1 - y;
166 for (unsigned x = 0; x < width; ++x) {
167 uint8_t r = sptr[(y2 * width + x) * 4 + 3];
168 uint8_t g = sptr[(y2 * width + x) * 4 + 2];
169 uint8_t b = sptr[(y2 * width + x) * 4 + 1];
172 pix[y * width + x] = lrintf(r * 0.2126f + g * 0.7152f + b * 0.0722f);
175 SDL_FreeSurface(rgb_surf);
178 for (int w = width, h = height; w > 1 || h > 1; ) {
185 glCreateTextures(GL_TEXTURE_2D, 1, &tex);
186 glTextureStorage2D(tex, levels, GL_R8, width, height);
187 glTextureSubImage2D(tex, 0, 0, 0, width, height, GL_RED, GL_UNSIGNED_BYTE, pix.get());
188 glGenerateTextureMipmap(tex);
191 *height_ret = height;
196 GLuint link_program(GLuint vs_obj, GLuint fs_obj)
198 GLuint program = glCreateProgram();
199 glAttachShader(program, vs_obj);
200 glAttachShader(program, fs_obj);
201 glLinkProgram(program);
203 glGetProgramiv(program, GL_LINK_STATUS, &success);
204 if (success == GL_FALSE) {
205 GLchar error_log[1024] = {0};
206 glGetProgramInfoLog(program, 1024, nullptr, error_log);
207 fprintf(stderr, "Error linking program: %s\n", error_log);
213 GLuint generate_vbo(GLint size, GLsizeiptr data_size, const GLvoid *data)
216 glCreateBuffers(1, &vbo);
217 glBufferData(GL_ARRAY_BUFFER, data_size, data, GL_STATIC_DRAW);
218 glNamedBufferData(vbo, data_size, data, GL_STATIC_DRAW);
222 GLuint fill_vertex_attribute(GLuint vao, GLuint glsl_program_num, const string &attribute_name, GLint size, GLenum type, GLsizeiptr data_size, const GLvoid *data)
224 int attrib = glGetAttribLocation(glsl_program_num, attribute_name.c_str());
229 GLuint vbo = generate_vbo(size, data_size, data);
231 glBindBuffer(GL_ARRAY_BUFFER, vbo);
232 glEnableVertexArrayAttrib(vao, attrib);
233 glVertexAttribPointer(attrib, size, type, GL_FALSE, 0, BUFFER_OFFSET(0));
234 glBindBuffer(GL_ARRAY_BUFFER, 0);
239 void bind_sampler(GLuint program, GLint location, GLuint texture_unit, GLuint tex, GLuint sampler)
241 if (location == -1) {
245 glBindTextureUnit(texture_unit, tex);
246 glBindSampler(texture_unit, sampler);
247 glProgramUniform1i(program, location, texture_unit);
250 // A class that caches FBOs that render to a given set of textures.
251 // It never frees anything, so it is only suitable for rendering to
252 // the same (small) set of textures over and over again.
253 template<size_t num_elements>
254 class PersistentFBOSet {
256 void render_to(const array<GLuint, num_elements> &textures);
258 // Convenience wrappers.
259 void render_to(GLuint texture0, enable_if<num_elements == 1> * = nullptr) {
260 render_to({{texture0}});
263 void render_to(GLuint texture0, GLuint texture1, enable_if<num_elements == 2> * = nullptr) {
264 render_to({{texture0, texture1}});
267 void render_to(GLuint texture0, GLuint texture1, GLuint texture2, enable_if<num_elements == 3> * = nullptr) {
268 render_to({{texture0, texture1, texture2}});
271 void render_to(GLuint texture0, GLuint texture1, GLuint texture2, GLuint texture3, enable_if<num_elements == 4> * = nullptr) {
272 render_to({{texture0, texture1, texture2, texture3}});
276 // TODO: Delete these on destruction.
277 map<array<GLuint, num_elements>, GLuint> fbos;
280 template<size_t num_elements>
281 void PersistentFBOSet<num_elements>::render_to(const array<GLuint, num_elements> &textures)
283 auto it = fbos.find(textures);
284 if (it != fbos.end()) {
285 glBindFramebuffer(GL_FRAMEBUFFER, it->second);
290 glCreateFramebuffers(1, &fbo);
291 GLenum bufs[num_elements];
292 for (size_t i = 0; i < num_elements; ++i) {
293 glNamedFramebufferTexture(fbo, GL_COLOR_ATTACHMENT0 + i, textures[i], 0);
294 bufs[i] = GL_COLOR_ATTACHMENT0 + i;
296 glNamedFramebufferDrawBuffers(fbo, num_elements, bufs);
298 fbos[textures] = fbo;
299 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
302 // Compute gradients in every point, used for the motion search.
303 // The DIS paper doesn't actually mention how these are computed,
304 // but seemingly, a 3x3 Sobel operator is used here (at least in
305 // later versions of the code), while a [1 -8 0 8 -1] kernel is
306 // used for all the derivatives in the variational refinement part
307 // (which borrows code from DeepFlow). This is inconsistent,
308 // but I guess we're better off with staying with the original
309 // decisions until we actually know having different ones would be better.
313 void exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height);
316 PersistentFBOSet<1> fbos;
319 GLuint sobel_program;
327 sobel_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
328 sobel_fs_obj = compile_shader(read_file("sobel.frag"), GL_FRAGMENT_SHADER);
329 sobel_program = link_program(sobel_vs_obj, sobel_fs_obj);
331 // Set up the VAO containing all the required position/texcoord data.
332 glCreateVertexArrays(1, &sobel_vao);
333 glBindVertexArray(sobel_vao);
335 GLint position_attrib = glGetAttribLocation(sobel_program, "position");
336 glEnableVertexArrayAttrib(sobel_vao, position_attrib);
337 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
339 uniform_tex = glGetUniformLocation(sobel_program, "tex");
342 void Sobel::exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height)
344 glUseProgram(sobel_program);
345 bind_sampler(sobel_program, uniform_tex, 0, tex0_view, nearest_sampler);
347 glViewport(0, 0, level_width, level_height);
348 fbos.render_to(grad0_tex);
349 glBindVertexArray(sobel_vao);
350 glUseProgram(sobel_program);
352 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
355 // Motion search to find the initial flow. See motion_search.frag for documentation.
359 void exec(GLuint tex0_view, GLuint tex1_view, GLuint grad0_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);
362 PersistentFBOSet<1> fbos;
364 GLuint motion_vs_obj;
365 GLuint motion_fs_obj;
366 GLuint motion_search_program;
367 GLuint motion_search_vao;
369 GLuint uniform_inv_image_size, uniform_inv_prev_level_size;
370 GLuint uniform_image0_tex, uniform_image1_tex, uniform_grad0_tex, uniform_flow_tex;
373 MotionSearch::MotionSearch()
375 motion_vs_obj = compile_shader(read_file("motion_search.vert"), GL_VERTEX_SHADER);
376 motion_fs_obj = compile_shader(read_file("motion_search.frag"), GL_FRAGMENT_SHADER);
377 motion_search_program = link_program(motion_vs_obj, motion_fs_obj);
379 // Set up the VAO containing all the required position/texcoord data.
380 glCreateVertexArrays(1, &motion_search_vao);
381 glBindVertexArray(motion_search_vao);
382 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
384 GLint position_attrib = glGetAttribLocation(motion_search_program, "position");
385 glEnableVertexArrayAttrib(motion_search_vao, position_attrib);
386 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
388 uniform_inv_image_size = glGetUniformLocation(motion_search_program, "inv_image_size");
389 uniform_inv_prev_level_size = glGetUniformLocation(motion_search_program, "inv_prev_level_size");
390 uniform_image0_tex = glGetUniformLocation(motion_search_program, "image0_tex");
391 uniform_image1_tex = glGetUniformLocation(motion_search_program, "image1_tex");
392 uniform_grad0_tex = glGetUniformLocation(motion_search_program, "grad0_tex");
393 uniform_flow_tex = glGetUniformLocation(motion_search_program, "flow_tex");
396 void MotionSearch::exec(GLuint tex0_view, GLuint tex1_view, GLuint grad0_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)
398 glUseProgram(motion_search_program);
400 bind_sampler(motion_search_program, uniform_image0_tex, 0, tex0_view, nearest_sampler);
401 bind_sampler(motion_search_program, uniform_image1_tex, 1, tex1_view, linear_sampler);
402 bind_sampler(motion_search_program, uniform_grad0_tex, 2, grad0_tex, zero_border_sampler);
403 bind_sampler(motion_search_program, uniform_flow_tex, 3, flow_tex, linear_sampler);
405 glProgramUniform2f(motion_search_program, uniform_inv_image_size, 1.0f / level_width, 1.0f / level_height);
406 glProgramUniform2f(motion_search_program, uniform_inv_prev_level_size, 1.0f / prev_level_width, 1.0f / prev_level_height);
408 glViewport(0, 0, width_patches, height_patches);
409 fbos.render_to(flow_out_tex);
410 glBindVertexArray(motion_search_vao);
411 glUseProgram(motion_search_program);
412 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
415 // Do “densification”, ie., upsampling of the flow patches to the flow field
416 // (the same size as the image at this level). We draw one quad per patch
417 // over its entire covered area (using instancing in the vertex shader),
418 // and then weight the contributions in the pixel shader by post-warp difference.
419 // This is equation (3) in the paper.
421 // We accumulate the flow vectors in the R/G channels (for u/v) and the total
422 // weight in the B channel. Dividing R and G by B gives the normalized values.
426 void exec(GLuint tex0_view, GLuint tex1_view, GLuint flow_tex, GLuint dense_flow_tex, int level_width, int level_height, int width_patches, int height_patches);
429 PersistentFBOSet<1> fbos;
431 GLuint densify_vs_obj;
432 GLuint densify_fs_obj;
433 GLuint densify_program;
436 GLuint uniform_patch_size, uniform_patch_spacing;
437 GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex;
442 densify_vs_obj = compile_shader(read_file("densify.vert"), GL_VERTEX_SHADER);
443 densify_fs_obj = compile_shader(read_file("densify.frag"), GL_FRAGMENT_SHADER);
444 densify_program = link_program(densify_vs_obj, densify_fs_obj);
446 // Set up the VAO containing all the required position/texcoord data.
447 glCreateVertexArrays(1, &densify_vao);
448 glBindVertexArray(densify_vao);
449 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
451 GLint position_attrib = glGetAttribLocation(densify_program, "position");
452 glEnableVertexArrayAttrib(densify_vao, position_attrib);
453 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
455 uniform_patch_size = glGetUniformLocation(densify_program, "patch_size");
456 uniform_patch_spacing = glGetUniformLocation(densify_program, "patch_spacing");
457 uniform_image0_tex = glGetUniformLocation(densify_program, "image0_tex");
458 uniform_image1_tex = glGetUniformLocation(densify_program, "image1_tex");
459 uniform_flow_tex = glGetUniformLocation(densify_program, "flow_tex");
462 void Densify::exec(GLuint tex0_view, GLuint tex1_view, GLuint flow_tex, GLuint dense_flow_tex, int level_width, int level_height, int width_patches, int height_patches)
464 glUseProgram(densify_program);
466 bind_sampler(densify_program, uniform_image0_tex, 0, tex0_view, nearest_sampler);
467 bind_sampler(densify_program, uniform_image1_tex, 1, tex1_view, linear_sampler);
468 bind_sampler(densify_program, uniform_flow_tex, 2, flow_tex, nearest_sampler);
470 glProgramUniform2f(densify_program, uniform_patch_size,
471 float(patch_size_pixels) / level_width,
472 float(patch_size_pixels) / level_height);
474 float patch_spacing_x = float(level_width - patch_size_pixels) / (width_patches - 1);
475 float patch_spacing_y = float(level_height - patch_size_pixels) / (height_patches - 1);
476 if (width_patches == 1) patch_spacing_x = 0.0f; // Avoid infinities.
477 if (height_patches == 1) patch_spacing_y = 0.0f;
478 glProgramUniform2f(densify_program, uniform_patch_spacing,
479 patch_spacing_x / level_width,
480 patch_spacing_y / level_height);
482 glViewport(0, 0, level_width, level_height);
484 glBlendFunc(GL_ONE, GL_ONE);
485 glBindVertexArray(densify_vao);
486 fbos.render_to(dense_flow_tex);
487 glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width_patches * height_patches);
490 // Warp I_1 to I_w, and then compute the mean (I) and difference (I_t) of
491 // I_0 and I_w. The prewarping is what enables us to solve the variational
492 // flow for du,dv instead of u,v.
494 // Also calculates the normalized flow, ie. divides by z (this is needed because
495 // Densify works by additive blending) and multiplies by the image size.
497 // See variational_refinement.txt for more information.
501 void exec(GLuint tex0_view, GLuint tex1_view, GLuint flow_tex, GLuint normalized_flow_tex, GLuint I_tex, GLuint I_t_tex, int level_width, int level_height);
504 PersistentFBOSet<3> fbos;
506 GLuint prewarp_vs_obj;
507 GLuint prewarp_fs_obj;
508 GLuint prewarp_program;
511 GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex;
516 prewarp_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
517 prewarp_fs_obj = compile_shader(read_file("prewarp.frag"), GL_FRAGMENT_SHADER);
518 prewarp_program = link_program(prewarp_vs_obj, prewarp_fs_obj);
520 // Set up the VAO containing all the required position/texcoord data.
521 glCreateVertexArrays(1, &prewarp_vao);
522 glBindVertexArray(prewarp_vao);
523 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
525 GLint position_attrib = glGetAttribLocation(prewarp_program, "position");
526 glEnableVertexArrayAttrib(prewarp_vao, position_attrib);
527 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
529 uniform_image0_tex = glGetUniformLocation(prewarp_program, "image0_tex");
530 uniform_image1_tex = glGetUniformLocation(prewarp_program, "image1_tex");
531 uniform_flow_tex = glGetUniformLocation(prewarp_program, "flow_tex");
534 void Prewarp::exec(GLuint tex0_view, GLuint tex1_view, GLuint flow_tex, GLuint I_tex, GLuint I_t_tex, GLuint normalized_flow_tex, int level_width, int level_height)
536 glUseProgram(prewarp_program);
538 bind_sampler(prewarp_program, uniform_image0_tex, 0, tex0_view, nearest_sampler);
539 bind_sampler(prewarp_program, uniform_image1_tex, 1, tex1_view, linear_sampler);
540 bind_sampler(prewarp_program, uniform_flow_tex, 2, flow_tex, nearest_sampler);
542 glViewport(0, 0, level_width, level_height);
544 glBindVertexArray(prewarp_vao);
545 fbos.render_to(I_tex, I_t_tex, normalized_flow_tex);
546 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
549 // From I, calculate the partial derivatives I_x and I_y. We use a four-tap
550 // central difference filter, since apparently, that's tradition (I haven't
551 // measured quality versus a more normal 0.5 (I[x+1] - I[x-1]).)
552 // The coefficients come from
554 // https://en.wikipedia.org/wiki/Finite_difference_coefficient
556 // Also computes β_0, since it depends only on I_x and I_y.
560 void exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, int level_width, int level_height);
563 PersistentFBOSet<2> fbos;
565 GLuint derivatives_vs_obj;
566 GLuint derivatives_fs_obj;
567 GLuint derivatives_program;
568 GLuint derivatives_vao;
573 Derivatives::Derivatives()
575 derivatives_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
576 derivatives_fs_obj = compile_shader(read_file("derivatives.frag"), GL_FRAGMENT_SHADER);
577 derivatives_program = link_program(derivatives_vs_obj, derivatives_fs_obj);
579 // Set up the VAO containing all the required position/texcoord data.
580 glCreateVertexArrays(1, &derivatives_vao);
581 glBindVertexArray(derivatives_vao);
582 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
584 GLint position_attrib = glGetAttribLocation(derivatives_program, "position");
585 glEnableVertexArrayAttrib(derivatives_vao, position_attrib);
586 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
588 uniform_tex = glGetUniformLocation(derivatives_program, "tex");
591 void Derivatives::exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, int level_width, int level_height)
593 glUseProgram(derivatives_program);
595 bind_sampler(derivatives_program, uniform_tex, 0, input_tex, nearest_sampler);
597 glViewport(0, 0, level_width, level_height);
599 glBindVertexArray(derivatives_vao);
600 fbos.render_to(I_x_y_tex, beta_0_tex);
601 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
604 // Calculate the smoothness constraints between neighboring pixels;
605 // s_x(x,y) stores smoothness between pixel (x,y) and (x+1,y),
606 // and s_y(x,y) stores between (x,y) and (x,y+1). We'll sample with
607 // border color (0,0) later, so that there's zero diffusion out of
610 // See variational_refinement.txt for more information.
611 class ComputeSmoothness {
614 void exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height);
617 PersistentFBOSet<2> fbos;
619 GLuint smoothness_vs_obj;
620 GLuint smoothness_fs_obj;
621 GLuint smoothness_program;
622 GLuint smoothness_vao;
624 GLuint uniform_flow_tex, uniform_diff_flow_tex;
625 GLuint uniform_alpha;
628 ComputeSmoothness::ComputeSmoothness()
630 smoothness_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
631 smoothness_fs_obj = compile_shader(read_file("smoothness.frag"), GL_FRAGMENT_SHADER);
632 smoothness_program = link_program(smoothness_vs_obj, smoothness_fs_obj);
634 // Set up the VAO containing all the required position/texcoord data.
635 glCreateVertexArrays(1, &smoothness_vao);
636 glBindVertexArray(smoothness_vao);
637 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
639 GLint position_attrib = glGetAttribLocation(smoothness_program, "position");
640 glEnableVertexArrayAttrib(smoothness_vao, position_attrib);
641 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
643 uniform_flow_tex = glGetUniformLocation(smoothness_program, "flow_tex");
644 uniform_diff_flow_tex = glGetUniformLocation(smoothness_program, "diff_flow_tex");
645 uniform_alpha = glGetUniformLocation(smoothness_program, "alpha");
648 void ComputeSmoothness::exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height)
650 glUseProgram(smoothness_program);
652 bind_sampler(smoothness_program, uniform_flow_tex, 0, flow_tex, nearest_sampler);
653 bind_sampler(smoothness_program, uniform_diff_flow_tex, 1, diff_flow_tex, nearest_sampler);
654 glProgramUniform1f(smoothness_program, uniform_alpha, vr_alpha);
656 glViewport(0, 0, level_width, level_height);
659 glBindVertexArray(smoothness_vao);
660 fbos.render_to(smoothness_x_tex, smoothness_y_tex);
661 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
663 // Make sure the smoothness on the right and upper borders is zero.
664 // We could have done this by making (W-1)xH and Wx(H-1) textures instead
665 // (we're sampling smoothness with all-zero border color), but we'd
666 // have to adjust the sampling coordinates, which is annoying.
667 glClearTexSubImage(smoothness_x_tex, 0, level_width - 1, 0, 0, 1, level_height, 1, GL_RED, GL_FLOAT, nullptr);
668 glClearTexSubImage(smoothness_y_tex, 0, 0, level_height - 1, 0, level_width, 1, 1, GL_RED, GL_FLOAT, nullptr);
671 // Set up the equations set (two equations in two unknowns, per pixel).
672 // We store five floats; the three non-redundant elements of the 2x2 matrix (A)
673 // as 32-bit floats, and the two elements on the right-hand side (b) as 16-bit
674 // floats. (Actually, we store the inverse of the diagonal elements, because
675 // we only ever need to divide by them.) This fits into four u32 values;
676 // R, G, B for the matrix (the last element is symmetric) and A for the two b values.
677 // All the values of the energy term (E_I, E_G, E_S), except the smoothness
678 // terms that depend on other pixels, are calculated in one pass.
680 // See variational_refinement.txt for more information.
681 class SetupEquations {
684 void exec(GLuint I_x_y_tex, GLuint I_t_tex, GLuint diff_flow_tex, GLuint flow_tex, GLuint beta_0_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, GLuint equation_tex, int level_width, int level_height);
687 PersistentFBOSet<1> fbos;
689 GLuint equations_vs_obj;
690 GLuint equations_fs_obj;
691 GLuint equations_program;
692 GLuint equations_vao;
694 GLuint uniform_I_x_y_tex, uniform_I_t_tex;
695 GLuint uniform_diff_flow_tex, uniform_base_flow_tex;
696 GLuint uniform_beta_0_tex;
697 GLuint uniform_smoothness_x_tex, uniform_smoothness_y_tex;
698 GLuint uniform_gamma, uniform_delta;
701 SetupEquations::SetupEquations()
703 equations_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
704 equations_fs_obj = compile_shader(read_file("equations.frag"), GL_FRAGMENT_SHADER);
705 equations_program = link_program(equations_vs_obj, equations_fs_obj);
707 // Set up the VAO containing all the required position/texcoord data.
708 glCreateVertexArrays(1, &equations_vao);
709 glBindVertexArray(equations_vao);
710 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
712 GLint position_attrib = glGetAttribLocation(equations_program, "position");
713 glEnableVertexArrayAttrib(equations_vao, position_attrib);
714 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
716 uniform_I_x_y_tex = glGetUniformLocation(equations_program, "I_x_y_tex");
717 uniform_I_t_tex = glGetUniformLocation(equations_program, "I_t_tex");
718 uniform_diff_flow_tex = glGetUniformLocation(equations_program, "diff_flow_tex");
719 uniform_base_flow_tex = glGetUniformLocation(equations_program, "base_flow_tex");
720 uniform_beta_0_tex = glGetUniformLocation(equations_program, "beta_0_tex");
721 uniform_smoothness_x_tex = glGetUniformLocation(equations_program, "smoothness_x_tex");
722 uniform_smoothness_y_tex = glGetUniformLocation(equations_program, "smoothness_y_tex");
723 uniform_gamma = glGetUniformLocation(equations_program, "gamma");
724 uniform_delta = glGetUniformLocation(equations_program, "delta");
727 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 smoothness_x_tex, GLuint smoothness_y_tex, GLuint equation_tex, int level_width, int level_height)
729 glUseProgram(equations_program);
731 bind_sampler(equations_program, uniform_I_x_y_tex, 0, I_x_y_tex, nearest_sampler);
732 bind_sampler(equations_program, uniform_I_t_tex, 1, I_t_tex, nearest_sampler);
733 bind_sampler(equations_program, uniform_diff_flow_tex, 2, diff_flow_tex, nearest_sampler);
734 bind_sampler(equations_program, uniform_base_flow_tex, 3, base_flow_tex, nearest_sampler);
735 bind_sampler(equations_program, uniform_beta_0_tex, 4, beta_0_tex, nearest_sampler);
736 bind_sampler(equations_program, uniform_smoothness_x_tex, 5, smoothness_x_tex, zero_border_sampler);
737 bind_sampler(equations_program, uniform_smoothness_y_tex, 6, smoothness_y_tex, zero_border_sampler);
738 glProgramUniform1f(equations_program, uniform_delta, vr_delta);
739 glProgramUniform1f(equations_program, uniform_gamma, vr_gamma);
741 glViewport(0, 0, level_width, level_height);
743 glBindVertexArray(equations_vao);
744 fbos.render_to(equation_tex);
745 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
748 // Actually solve the equation sets made by SetupEquations, by means of
749 // successive over-relaxation (SOR).
751 // See variational_refinement.txt for more information.
755 void exec(GLuint diff_flow_tex, GLuint equation_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height, int num_iterations);
758 PersistentFBOSet<1> fbos;
765 GLuint uniform_diff_flow_tex;
766 GLuint uniform_equation_tex;
767 GLuint uniform_smoothness_x_tex, uniform_smoothness_y_tex;
768 GLuint uniform_phase;
773 sor_vs_obj = compile_shader(read_file("sor.vert"), GL_VERTEX_SHADER);
774 sor_fs_obj = compile_shader(read_file("sor.frag"), GL_FRAGMENT_SHADER);
775 sor_program = link_program(sor_vs_obj, sor_fs_obj);
777 // Set up the VAO containing all the required position/texcoord data.
778 glCreateVertexArrays(1, &sor_vao);
779 glBindVertexArray(sor_vao);
780 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
782 GLint position_attrib = glGetAttribLocation(sor_program, "position");
783 glEnableVertexArrayAttrib(sor_vao, position_attrib);
784 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
786 uniform_diff_flow_tex = glGetUniformLocation(sor_program, "diff_flow_tex");
787 uniform_equation_tex = glGetUniformLocation(sor_program, "equation_tex");
788 uniform_smoothness_x_tex = glGetUniformLocation(sor_program, "smoothness_x_tex");
789 uniform_smoothness_y_tex = glGetUniformLocation(sor_program, "smoothness_y_tex");
790 uniform_phase = glGetUniformLocation(sor_program, "phase");
793 void SOR::exec(GLuint diff_flow_tex, GLuint equation_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height, int num_iterations)
795 glUseProgram(sor_program);
797 bind_sampler(sor_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler);
798 bind_sampler(sor_program, uniform_smoothness_x_tex, 1, smoothness_x_tex, zero_border_sampler);
799 bind_sampler(sor_program, uniform_smoothness_y_tex, 2, smoothness_y_tex, zero_border_sampler);
800 bind_sampler(sor_program, uniform_equation_tex, 3, equation_tex, nearest_sampler);
802 // NOTE: We bind to the texture we are rendering from, but we never write any value
803 // that we read in the same shader pass (we call discard for red values when we compute
804 // black, and vice versa), and we have barriers between the passes, so we're fine
806 glViewport(0, 0, level_width, level_height);
808 glBindVertexArray(sor_vao);
809 fbos.render_to(diff_flow_tex);
811 for (int i = 0; i < num_iterations; ++i) {
812 glProgramUniform1i(sor_program, uniform_phase, 0);
813 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
815 glProgramUniform1i(sor_program, uniform_phase, 1);
816 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
817 if (i != num_iterations - 1) {
823 // Simply add the differential flow found by the variational refinement to the base flow.
824 // The output is in base_flow_tex; we don't need to make a new texture.
828 void exec(GLuint base_flow_tex, GLuint diff_flow_tex, int level_width, int level_height);
831 PersistentFBOSet<1> fbos;
833 GLuint add_flow_vs_obj;
834 GLuint add_flow_fs_obj;
835 GLuint add_flow_program;
838 GLuint uniform_diff_flow_tex;
841 AddBaseFlow::AddBaseFlow()
843 add_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
844 add_flow_fs_obj = compile_shader(read_file("add_base_flow.frag"), GL_FRAGMENT_SHADER);
845 add_flow_program = link_program(add_flow_vs_obj, add_flow_fs_obj);
847 // Set up the VAO containing all the required position/texcoord data.
848 glCreateVertexArrays(1, &add_flow_vao);
849 glBindVertexArray(add_flow_vao);
850 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
852 GLint position_attrib = glGetAttribLocation(add_flow_program, "position");
853 glEnableVertexArrayAttrib(add_flow_vao, position_attrib);
854 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
856 uniform_diff_flow_tex = glGetUniformLocation(add_flow_program, "diff_flow_tex");
859 void AddBaseFlow::exec(GLuint base_flow_tex, GLuint diff_flow_tex, int level_width, int level_height)
861 glUseProgram(add_flow_program);
863 bind_sampler(add_flow_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler);
865 glViewport(0, 0, level_width, level_height);
867 glBlendFunc(GL_ONE, GL_ONE);
868 glBindVertexArray(add_flow_vao);
869 fbos.render_to(base_flow_tex);
871 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
874 // Take a copy of the flow, bilinearly interpolated and scaled up.
878 void exec(GLuint in_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height);
881 PersistentFBOSet<1> fbos;
883 GLuint resize_flow_vs_obj;
884 GLuint resize_flow_fs_obj;
885 GLuint resize_flow_program;
886 GLuint resize_flow_vao;
888 GLuint uniform_flow_tex;
889 GLuint uniform_scale_factor;
892 ResizeFlow::ResizeFlow()
894 resize_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
895 resize_flow_fs_obj = compile_shader(read_file("resize_flow.frag"), GL_FRAGMENT_SHADER);
896 resize_flow_program = link_program(resize_flow_vs_obj, resize_flow_fs_obj);
898 // Set up the VAO containing all the required position/texcoord data.
899 glCreateVertexArrays(1, &resize_flow_vao);
900 glBindVertexArray(resize_flow_vao);
901 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
903 GLint position_attrib = glGetAttribLocation(resize_flow_program, "position");
904 glEnableVertexArrayAttrib(resize_flow_vao, position_attrib);
905 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
907 uniform_flow_tex = glGetUniformLocation(resize_flow_program, "flow_tex");
908 uniform_scale_factor = glGetUniformLocation(resize_flow_program, "scale_factor");
911 void ResizeFlow::exec(GLuint flow_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height)
913 glUseProgram(resize_flow_program);
915 bind_sampler(resize_flow_program, uniform_flow_tex, 0, flow_tex, nearest_sampler);
917 glProgramUniform2f(resize_flow_program, uniform_scale_factor, float(output_width) / input_width, float(output_height) / input_height);
919 glViewport(0, 0, output_width, output_height);
921 glBindVertexArray(resize_flow_vao);
922 fbos.render_to(out_tex);
924 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
930 pair<GLuint, GLuint> begin_timer(const string &name, int level);
936 pair<GLuint, GLuint> query;
938 vector<Timer> timers;
941 pair<GLuint, GLuint> GPUTimers::begin_timer(const string &name, int level)
943 if (!enable_timing) {
944 return make_pair(0, 0);
948 glGenQueries(2, queries);
949 glQueryCounter(queries[0], GL_TIMESTAMP);
954 timer.query.first = queries[0];
955 timer.query.second = queries[1];
956 timers.push_back(timer);
960 void GPUTimers::print()
962 for (const Timer &timer : timers) {
963 // NOTE: This makes the CPU wait for the GPU.
964 GLuint64 time_start, time_end;
965 glGetQueryObjectui64v(timer.query.first, GL_QUERY_RESULT, &time_start);
966 glGetQueryObjectui64v(timer.query.second, GL_QUERY_RESULT, &time_end);
967 //fprintf(stderr, "GPU time used = %.1f ms\n", time_elapsed / 1e6);
968 for (int i = 0; i < timer.level * 2; ++i) {
969 fprintf(stderr, " ");
971 fprintf(stderr, "%-30s %4.1f ms\n", timer.name.c_str(), GLint64(time_end - time_start) / 1e6);
975 // A simple RAII class for timing until the end of the scope.
978 ScopedTimer(const string &name, GPUTimers *timers)
979 : timers(timers), level(0)
981 query = timers->begin_timer(name, level);
984 ScopedTimer(const string &name, ScopedTimer *parent_timer)
985 : timers(parent_timer->timers),
986 level(parent_timer->level + 1)
988 query = timers->begin_timer(name, level);
998 if (enable_timing && !ended) {
999 glQueryCounter(query.second, GL_TIMESTAMP);
1007 pair<GLuint, GLuint> query;
1011 class DISComputeFlow {
1013 DISComputeFlow(int width, int height);
1015 // Returns a texture that must be released with release_texture()
1017 GLuint exec(GLuint tex0, GLuint tex1);
1018 void release_texture(GLuint tex);
1022 GLuint initial_flow_tex;
1024 // The various passes.
1026 MotionSearch motion_search;
1029 Derivatives derivatives;
1030 ComputeSmoothness compute_smoothness;
1031 SetupEquations setup_equations;
1033 AddBaseFlow add_base_flow;
1034 ResizeFlow resize_flow;
1039 GLuint width, height;
1040 bool in_use = false;
1042 vector<Texture> textures;
1044 GLuint get_texture(GLenum format, GLuint width, GLuint height);
1047 DISComputeFlow::DISComputeFlow(int width, int height)
1048 : width(width), height(height)
1050 // Make some samplers.
1051 glCreateSamplers(1, &nearest_sampler);
1052 glSamplerParameteri(nearest_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
1053 glSamplerParameteri(nearest_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
1054 glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
1055 glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
1057 glCreateSamplers(1, &linear_sampler);
1058 glSamplerParameteri(linear_sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
1059 glSamplerParameteri(linear_sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
1060 glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
1061 glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
1063 // The smoothness is sampled so that once we get to a smoothness involving
1064 // a value outside the border, the diffusivity between the two becomes zero.
1065 // Similarly, gradients are zero outside the border, since the edge is taken
1067 glCreateSamplers(1, &zero_border_sampler);
1068 glSamplerParameteri(zero_border_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
1069 glSamplerParameteri(zero_border_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
1070 glSamplerParameteri(zero_border_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
1071 glSamplerParameteri(zero_border_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
1072 float zero[] = { 0.0f, 0.0f, 0.0f, 0.0f };
1073 glSamplerParameterfv(zero_border_sampler, GL_TEXTURE_BORDER_COLOR, zero);
1075 // Initial flow is zero, 1x1.
1076 glCreateTextures(GL_TEXTURE_2D, 1, &initial_flow_tex);
1077 glTextureStorage2D(initial_flow_tex, 1, GL_RG16F, 1, 1);
1078 glClearTexImage(initial_flow_tex, 0, GL_RG, GL_FLOAT, nullptr);
1081 GLuint DISComputeFlow::exec(GLuint tex0, GLuint tex1)
1083 for (const Texture &tex : textures) {
1084 assert(!tex.in_use);
1087 int prev_level_width = 1, prev_level_height = 1;
1088 GLuint prev_level_flow_tex = initial_flow_tex;
1092 ScopedTimer total_timer("Total", &timers);
1093 for (int level = coarsest_level; level >= int(finest_level); --level) {
1094 char timer_name[256];
1095 snprintf(timer_name, sizeof(timer_name), "Level %d", level);
1096 ScopedTimer level_timer(timer_name, &total_timer);
1098 int level_width = width >> level;
1099 int level_height = height >> level;
1100 float patch_spacing_pixels = patch_size_pixels * (1.0f - patch_overlap_ratio);
1102 // Make sure we have patches at least every Nth pixel, e.g. for width=9
1103 // and patch_spacing=3 (the default), we put out patch centers in
1104 // x=0, x=3, x=6, x=9, which is four patches. The fragment shader will
1105 // lock all the centers to integer coordinates if needed.
1106 int width_patches = 1 + ceil(level_width / patch_spacing_pixels);
1107 int height_patches = 1 + ceil(level_height / patch_spacing_pixels);
1109 // Make sure we always read from the correct level; the chosen
1110 // mipmapping could otherwise be rather unpredictable, especially
1111 // during motion search.
1112 GLuint tex0_view, tex1_view;
1113 glGenTextures(1, &tex0_view);
1114 glTextureView(tex0_view, GL_TEXTURE_2D, tex0, GL_R8, level, 1, 0, 1);
1115 glGenTextures(1, &tex1_view);
1116 glTextureView(tex1_view, GL_TEXTURE_2D, tex1, GL_R8, level, 1, 0, 1);
1118 // Create a new texture; we could be fancy and render use a multi-level
1119 // texture, but meh.
1120 GLuint grad0_tex = get_texture(GL_RG16F, level_width, level_height);
1122 // Find the derivative.
1124 ScopedTimer timer("Sobel", &level_timer);
1125 sobel.exec(tex0_view, grad0_tex, level_width, level_height);
1128 // Motion search to find the initial flow. We use the flow from the previous
1129 // level (sampled bilinearly; no fancy tricks) as a guide, then search from there.
1131 // Create an output flow texture.
1132 GLuint flow_out_tex = get_texture(GL_RGB16F, width_patches, height_patches);
1136 ScopedTimer timer("Motion search", &level_timer);
1137 motion_search.exec(tex0_view, tex1_view, grad0_tex, prev_level_flow_tex, flow_out_tex, level_width, level_height, prev_level_width, prev_level_height, width_patches, height_patches);
1139 release_texture(grad0_tex);
1143 // Set up an output texture (initially zero).
1144 GLuint dense_flow_tex = get_texture(GL_RGB16F, level_width, level_height);
1145 glClearTexImage(dense_flow_tex, 0, GL_RGB, GL_FLOAT, nullptr);
1149 ScopedTimer timer("Densification", &level_timer);
1150 densify.exec(tex0_view, tex1_view, flow_out_tex, dense_flow_tex, level_width, level_height, width_patches, height_patches);
1152 release_texture(flow_out_tex);
1154 // Everything below here in the loop belongs to variational refinement.
1155 ScopedTimer varref_timer("Variational refinement", &level_timer);
1157 // Prewarping; create I and I_t, and a normalized base flow (so we don't
1158 // have to normalize it over and over again, and also save some bandwidth).
1160 // During the entire rest of the variational refinement, flow will be measured
1161 // in pixels, not 0..1 normalized OpenGL texture coordinates.
1162 // This is because variational refinement depends so heavily on derivatives,
1163 // which are measured in intensity levels per pixel.
1164 GLuint I_tex = get_texture(GL_R16F, level_width, level_height);
1165 GLuint I_t_tex = get_texture(GL_R16F, level_width, level_height);
1166 GLuint base_flow_tex = get_texture(GL_RG16F, level_width, level_height);
1168 ScopedTimer timer("Prewarping", &varref_timer);
1169 prewarp.exec(tex0_view, tex1_view, dense_flow_tex, I_tex, I_t_tex, base_flow_tex, level_width, level_height);
1171 release_texture(dense_flow_tex);
1172 glDeleteTextures(1, &tex0_view);
1173 glDeleteTextures(1, &tex1_view);
1175 // Calculate I_x and I_y. We're only calculating first derivatives;
1176 // the others will be taken on-the-fly in order to sample from fewer
1177 // textures overall, since sampling from the L1 cache is cheap.
1178 // (TODO: Verify that this is indeed faster than making separate
1179 // double-derivative textures.)
1180 GLuint I_x_y_tex = get_texture(GL_RG16F, level_width, level_height);
1181 GLuint beta_0_tex = get_texture(GL_R16F, level_width, level_height);
1183 ScopedTimer timer("First derivatives", &varref_timer);
1184 derivatives.exec(I_tex, I_x_y_tex, beta_0_tex, level_width, level_height);
1186 release_texture(I_tex);
1188 // We need somewhere to store du and dv (the flow increment, relative
1189 // to the non-refined base flow u0 and v0). It starts at zero.
1190 GLuint du_dv_tex = get_texture(GL_RG16F, level_width, level_height);
1191 glClearTexImage(du_dv_tex, 0, GL_RG, GL_FLOAT, nullptr);
1193 // And for smoothness.
1194 GLuint smoothness_x_tex = get_texture(GL_R16F, level_width, level_height);
1195 GLuint smoothness_y_tex = get_texture(GL_R16F, level_width, level_height);
1197 // And finally for the equation set. See SetupEquations for
1198 // the storage format.
1199 GLuint equation_tex = get_texture(GL_RGBA32UI, level_width, level_height);
1201 for (int outer_idx = 0; outer_idx < level + 1; ++outer_idx) {
1202 // Calculate the smoothness terms between the neighboring pixels,
1203 // both in x and y direction.
1205 ScopedTimer timer("Compute smoothness", &varref_timer);
1206 compute_smoothness.exec(base_flow_tex, du_dv_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height);
1209 // Set up the 2x2 equation system for each pixel.
1211 ScopedTimer timer("Set up equations", &varref_timer);
1212 setup_equations.exec(I_x_y_tex, I_t_tex, du_dv_tex, base_flow_tex, beta_0_tex, smoothness_x_tex, smoothness_y_tex, equation_tex, level_width, level_height);
1215 // Run a few SOR (or quasi-SOR, since we're not really Jacobi) iterations.
1216 // Note that these are to/from the same texture.
1218 ScopedTimer timer("SOR", &varref_timer);
1219 sor.exec(du_dv_tex, equation_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height, 5);
1223 release_texture(I_t_tex);
1224 release_texture(I_x_y_tex);
1225 release_texture(beta_0_tex);
1226 release_texture(smoothness_x_tex);
1227 release_texture(smoothness_y_tex);
1228 release_texture(equation_tex);
1230 // Add the differential flow found by the variational refinement to the base flow,
1231 // giving the final flow estimate for this level.
1232 // The output is in diff_flow_tex; we don't need to make a new texture.
1234 // Disabling this doesn't save any time (although we could easily make it so that
1235 // it is more efficient), but it helps debug the motion search.
1236 if (enable_variational_refinement) {
1237 ScopedTimer timer("Add differential flow", &varref_timer);
1238 add_base_flow.exec(base_flow_tex, du_dv_tex, level_width, level_height);
1240 release_texture(du_dv_tex);
1242 if (prev_level_flow_tex != initial_flow_tex) {
1243 release_texture(prev_level_flow_tex);
1245 prev_level_flow_tex = base_flow_tex;
1246 prev_level_width = level_width;
1247 prev_level_height = level_height;
1253 // Scale up the flow to the final size (if needed).
1254 if (finest_level == 0) {
1255 return prev_level_flow_tex;
1257 GLuint final_tex = get_texture(GL_RG16F, width, height);
1258 resize_flow.exec(prev_level_flow_tex, final_tex, prev_level_width, prev_level_height, width, height);
1259 release_texture(prev_level_flow_tex);
1264 GLuint DISComputeFlow::get_texture(GLenum format, GLuint width, GLuint height)
1266 for (Texture &tex : textures) {
1267 if (!tex.in_use && tex.format == format &&
1268 tex.width == width && tex.height == height) {
1275 glCreateTextures(GL_TEXTURE_2D, 1, &tex.tex_num);
1276 glTextureStorage2D(tex.tex_num, 1, format, width, height);
1277 tex.format = format;
1279 tex.height = height;
1281 textures.push_back(tex);
1285 void DISComputeFlow::release_texture(GLuint tex_num)
1287 for (Texture &tex : textures) {
1288 if (tex.tex_num == tex_num) {
1297 // OpenGL uses a bottom-left coordinate system, .flo files use a top-left coordinate system.
1298 void flip_coordinate_system(float *dense_flow, unsigned width, unsigned height)
1300 for (unsigned i = 0; i < width * height; ++i) {
1301 dense_flow[i * 2 + 1] = -dense_flow[i * 2 + 1];
1305 void write_flow(const char *filename, const float *dense_flow, unsigned width, unsigned height)
1307 FILE *flowfp = fopen(filename, "wb");
1308 fprintf(flowfp, "FEIH");
1309 fwrite(&width, 4, 1, flowfp);
1310 fwrite(&height, 4, 1, flowfp);
1311 for (unsigned y = 0; y < height; ++y) {
1312 int yy = height - y - 1;
1313 fwrite(&dense_flow[yy * width * 2], width * 2 * sizeof(float), 1, flowfp);
1318 void write_ppm(const char *filename, const float *dense_flow, unsigned width, unsigned height)
1320 FILE *fp = fopen(filename, "wb");
1321 fprintf(fp, "P6\n%d %d\n255\n", width, height);
1322 for (unsigned y = 0; y < unsigned(height); ++y) {
1323 int yy = height - y - 1;
1324 for (unsigned x = 0; x < unsigned(width); ++x) {
1325 float du = dense_flow[(yy * width + x) * 2 + 0];
1326 float dv = dense_flow[(yy * width + x) * 2 + 1];
1329 flow2rgb(du, dv, &r, &g, &b);
1338 void finish_one_read(GLuint width, GLuint height)
1340 assert(!reads_in_progress.empty());
1341 ReadInProgress read = reads_in_progress.front();
1342 reads_in_progress.pop_front();
1344 unique_ptr<float[]> flow(new float[width * height * 2]);
1345 void *buf = glMapNamedBufferRange(read.pbo, 0, width * height * 2 * sizeof(float), GL_MAP_READ_BIT); // Blocks if the read isn't done yet.
1346 memcpy(flow.get(), buf, width * height * 2 * sizeof(float));
1347 glUnmapNamedBuffer(read.pbo);
1348 spare_pbos.push(read.pbo);
1350 flip_coordinate_system(flow.get(), width, height);
1351 if (!read.flow_filename.empty()) {
1352 write_flow(read.flow_filename.c_str(), flow.get(), width, height);
1353 fprintf(stderr, "%s %s -> %s\n", read.filename0.c_str(), read.filename1.c_str(), read.flow_filename.c_str());
1355 if (!read.ppm_filename.empty()) {
1356 write_ppm(read.ppm_filename.c_str(), flow.get(), width, height);
1360 void schedule_read(GLuint tex, GLuint width, GLuint height, const char *filename0, const char *filename1, const char *flow_filename, const char *ppm_filename)
1362 if (spare_pbos.empty()) {
1363 finish_one_read(width, height);
1365 assert(!spare_pbos.empty());
1366 reads_in_progress.emplace_back(ReadInProgress{ spare_pbos.top(), filename0, filename1, flow_filename, ppm_filename });
1367 glBindBuffer(GL_PIXEL_PACK_BUFFER, spare_pbos.top());
1369 glGetTextureImage(tex, 0, GL_RG, GL_FLOAT, width * height * 2 * sizeof(float), nullptr);
1370 glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
1373 int main(int argc, char **argv)
1375 static const option long_options[] = {
1376 { "smoothness-relative-weight", required_argument, 0, 's' }, // alpha.
1377 { "intensity-relative-weight", required_argument, 0, 'i' }, // delta.
1378 { "gradient-relative-weight", required_argument, 0, 'g' }, // gamma.
1379 { "disable-timing", no_argument, 0, 1000 },
1380 { "ignore-variational-refinement", no_argument, 0, 1001 } // Still calculates it, just doesn't apply it.
1384 int option_index = 0;
1385 int c = getopt_long(argc, argv, "s:i:g:", long_options, &option_index);
1392 vr_alpha = atof(optarg);
1395 vr_delta = atof(optarg);
1398 vr_gamma = atof(optarg);
1401 enable_timing = false;
1404 enable_variational_refinement = false;
1407 fprintf(stderr, "Unknown option '%s'\n", argv[option_index]);
1412 if (SDL_Init(SDL_INIT_EVERYTHING) == -1) {
1413 fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError());
1416 SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
1417 SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0);
1418 SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0);
1419 SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
1421 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
1422 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
1423 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 5);
1424 // SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
1425 SDL_Window *window = SDL_CreateWindow("OpenGL window",
1426 SDL_WINDOWPOS_UNDEFINED,
1427 SDL_WINDOWPOS_UNDEFINED,
1430 SDL_GLContext context = SDL_GL_CreateContext(window);
1431 assert(context != nullptr);
1433 const char *filename0 = argc >= (optind + 1) ? argv[optind] : "test1499.png";
1434 const char *filename1 = argc >= (optind + 2) ? argv[optind + 1] : "test1500.png";
1435 const char *flow_filename = argc >= (optind + 3) ? argv[optind + 2] : "flow.flo";
1438 unsigned width1, height1, width2, height2;
1439 GLuint tex0 = load_texture(filename0, &width1, &height1);
1440 GLuint tex1 = load_texture(filename1, &width2, &height2);
1442 if (width1 != width2 || height1 != height2) {
1443 fprintf(stderr, "Image dimensions don't match (%dx%d versus %dx%d)\n",
1444 width1, height1, width2, height2);
1448 // Set up some PBOs to do asynchronous readback.
1450 glCreateBuffers(5, pbos);
1451 for (int i = 0; i < 5; ++i) {
1452 glNamedBufferData(pbos[i], width1 * height1 * 2 * sizeof(float), nullptr, GL_STREAM_READ);
1453 spare_pbos.push(pbos[i]);
1456 // FIXME: Should be part of DISComputeFlow (but needs to be initialized
1457 // before all the render passes).
1458 float vertices[] = {
1464 glCreateBuffers(1, &vertex_vbo);
1465 glNamedBufferData(vertex_vbo, sizeof(vertices), vertices, GL_STATIC_DRAW);
1466 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
1468 DISComputeFlow compute_flow(width1, height1);
1469 GLuint final_tex = compute_flow.exec(tex0, tex1);
1471 schedule_read(final_tex, width1, height1, filename0, filename1, flow_filename, "flow.ppm");
1472 compute_flow.release_texture(final_tex);
1474 // See if there are more flows on the command line (ie., more than three arguments),
1475 // and if so, process them.
1476 int num_flows = (argc - optind) / 3;
1477 for (int i = 1; i < num_flows; ++i) {
1478 const char *filename0 = argv[optind + i * 3 + 0];
1479 const char *filename1 = argv[optind + i * 3 + 1];
1480 const char *flow_filename = argv[optind + i * 3 + 2];
1481 GLuint width, height;
1482 GLuint tex0 = load_texture(filename0, &width, &height);
1483 if (width != width1 || height != height1) {
1484 fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n",
1485 filename0, width, height, width1, height1);
1489 GLuint tex1 = load_texture(filename1, &width, &height);
1490 if (width != width1 || height != height1) {
1491 fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n",
1492 filename1, width, height, width1, height1);
1496 GLuint final_tex = compute_flow.exec(tex0, tex1);
1497 schedule_read(final_tex, width1, height1, filename0, filename1, flow_filename, "");
1498 compute_flow.release_texture(final_tex);
1501 while (!reads_in_progress.empty()) {
1502 finish_one_read(width1, height1);