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 float vr_gamma = 10.0f, vr_delta = 5.0f, vr_alpha = 10.0f;
42 bool enable_timing = true;
43 bool enable_variational_refinement = true; // Just for debugging.
45 // Some global OpenGL objects.
46 // TODO: These should really be part of DISComputeFlow.
47 GLuint nearest_sampler, linear_sampler, zero_border_sampler;
50 // Structures for asynchronous readback. We assume everything is the same size (and GL_RG16F).
51 struct ReadInProgress {
53 string filename0, filename1;
54 string flow_filename, ppm_filename; // Either may be empty for no write.
56 stack<GLuint> spare_pbos;
57 deque<ReadInProgress> reads_in_progress;
59 string read_file(const string &filename)
61 FILE *fp = fopen(filename.c_str(), "r");
63 perror(filename.c_str());
67 int ret = fseek(fp, 0, SEEK_END);
69 perror("fseek(SEEK_END)");
75 ret = fseek(fp, 0, SEEK_SET);
77 perror("fseek(SEEK_SET)");
83 ret = fread(&str[0], size, 1, fp);
89 fprintf(stderr, "Short read when trying to read %d bytes from %s\n",
90 size, filename.c_str());
99 GLuint compile_shader(const string &shader_src, GLenum type)
101 GLuint obj = glCreateShader(type);
102 const GLchar* source[] = { shader_src.data() };
103 const GLint length[] = { (GLint)shader_src.size() };
104 glShaderSource(obj, 1, source, length);
105 glCompileShader(obj);
107 GLchar info_log[4096];
108 GLsizei log_length = sizeof(info_log) - 1;
109 glGetShaderInfoLog(obj, log_length, &log_length, info_log);
110 info_log[log_length] = 0;
111 if (strlen(info_log) > 0) {
112 fprintf(stderr, "Shader compile log: %s\n", info_log);
116 glGetShaderiv(obj, GL_COMPILE_STATUS, &status);
117 if (status == GL_FALSE) {
118 // Add some line numbers to easier identify compile errors.
119 string src_with_lines = "/* 1 */ ";
121 for (char ch : shader_src) {
122 src_with_lines.push_back(ch);
125 snprintf(buf, sizeof(buf), "/* %3zu */ ", ++lineno);
126 src_with_lines += buf;
130 fprintf(stderr, "Failed to compile shader:\n%s\n", src_with_lines.c_str());
137 GLuint load_texture(const char *filename, unsigned *width_ret, unsigned *height_ret)
139 SDL_Surface *surf = IMG_Load(filename);
140 if (surf == nullptr) {
141 fprintf(stderr, "IMG_Load(%s): %s\n", filename, IMG_GetError());
145 // For whatever reason, SDL doesn't support converting to YUV surfaces
146 // nor grayscale, so we'll do it (slowly) ourselves.
147 SDL_Surface *rgb_surf = SDL_ConvertSurfaceFormat(surf, SDL_PIXELFORMAT_RGBA8888, /*flags=*/0);
148 if (rgb_surf == nullptr) {
149 fprintf(stderr, "SDL_ConvertSurfaceFormat(%s): %s\n", filename, SDL_GetError());
153 SDL_FreeSurface(surf);
155 unsigned width = rgb_surf->w, height = rgb_surf->h;
156 const uint8_t *sptr = (uint8_t *)rgb_surf->pixels;
157 unique_ptr<uint8_t[]> pix(new uint8_t[width * height]);
159 // Extract the Y component, and convert to bottom-left origin.
160 for (unsigned y = 0; y < height; ++y) {
161 unsigned y2 = height - 1 - y;
162 for (unsigned x = 0; x < width; ++x) {
163 uint8_t r = sptr[(y2 * width + x) * 4 + 3];
164 uint8_t g = sptr[(y2 * width + x) * 4 + 2];
165 uint8_t b = sptr[(y2 * width + x) * 4 + 1];
168 pix[y * width + x] = lrintf(r * 0.2126f + g * 0.7152f + b * 0.0722f);
171 SDL_FreeSurface(rgb_surf);
174 for (int w = width, h = height; w > 1 || h > 1; ) {
181 glCreateTextures(GL_TEXTURE_2D, 1, &tex);
182 glTextureStorage2D(tex, levels, GL_R8, width, height);
183 glTextureSubImage2D(tex, 0, 0, 0, width, height, GL_RED, GL_UNSIGNED_BYTE, pix.get());
184 glGenerateTextureMipmap(tex);
187 *height_ret = height;
192 GLuint link_program(GLuint vs_obj, GLuint fs_obj)
194 GLuint program = glCreateProgram();
195 glAttachShader(program, vs_obj);
196 glAttachShader(program, fs_obj);
197 glLinkProgram(program);
199 glGetProgramiv(program, GL_LINK_STATUS, &success);
200 if (success == GL_FALSE) {
201 GLchar error_log[1024] = {0};
202 glGetProgramInfoLog(program, 1024, nullptr, error_log);
203 fprintf(stderr, "Error linking program: %s\n", error_log);
209 GLuint generate_vbo(GLint size, GLsizeiptr data_size, const GLvoid *data)
212 glCreateBuffers(1, &vbo);
213 glBufferData(GL_ARRAY_BUFFER, data_size, data, GL_STATIC_DRAW);
214 glNamedBufferData(vbo, data_size, data, GL_STATIC_DRAW);
218 GLuint fill_vertex_attribute(GLuint vao, GLuint glsl_program_num, const string &attribute_name, GLint size, GLenum type, GLsizeiptr data_size, const GLvoid *data)
220 int attrib = glGetAttribLocation(glsl_program_num, attribute_name.c_str());
225 GLuint vbo = generate_vbo(size, data_size, data);
227 glBindBuffer(GL_ARRAY_BUFFER, vbo);
228 glEnableVertexArrayAttrib(vao, attrib);
229 glVertexAttribPointer(attrib, size, type, GL_FALSE, 0, BUFFER_OFFSET(0));
230 glBindBuffer(GL_ARRAY_BUFFER, 0);
235 void bind_sampler(GLuint program, GLint location, GLuint texture_unit, GLuint tex, GLuint sampler)
237 if (location == -1) {
241 glBindTextureUnit(texture_unit, tex);
242 glBindSampler(texture_unit, sampler);
243 glProgramUniform1i(program, location, texture_unit);
246 // A class that caches FBOs that render to a given set of textures.
247 // It never frees anything, so it is only suitable for rendering to
248 // the same (small) set of textures over and over again.
249 template<size_t num_elements>
250 class PersistentFBOSet {
252 void render_to(const array<GLuint, num_elements> &textures);
254 // Convenience wrappers.
255 void render_to(GLuint texture0, enable_if<num_elements == 1> * = nullptr) {
256 render_to({{texture0}});
259 void render_to(GLuint texture0, GLuint texture1, enable_if<num_elements == 2> * = nullptr) {
260 render_to({{texture0, texture1}});
263 void render_to(GLuint texture0, GLuint texture1, GLuint texture2, enable_if<num_elements == 3> * = nullptr) {
264 render_to({{texture0, texture1, texture2}});
267 void render_to(GLuint texture0, GLuint texture1, GLuint texture2, GLuint texture3, enable_if<num_elements == 4> * = nullptr) {
268 render_to({{texture0, texture1, texture2, texture3}});
272 // TODO: Delete these on destruction.
273 map<array<GLuint, num_elements>, GLuint> fbos;
276 template<size_t num_elements>
277 void PersistentFBOSet<num_elements>::render_to(const array<GLuint, num_elements> &textures)
279 auto it = fbos.find(textures);
280 if (it != fbos.end()) {
281 glBindFramebuffer(GL_FRAMEBUFFER, it->second);
286 glCreateFramebuffers(1, &fbo);
287 GLenum bufs[num_elements];
288 for (size_t i = 0; i < num_elements; ++i) {
289 glNamedFramebufferTexture(fbo, GL_COLOR_ATTACHMENT0 + i, textures[i], 0);
290 bufs[i] = GL_COLOR_ATTACHMENT0 + i;
292 glNamedFramebufferDrawBuffers(fbo, num_elements, bufs);
294 fbos[textures] = fbo;
295 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
298 // Compute gradients in every point, used for the motion search.
299 // The DIS paper doesn't actually mention how these are computed,
300 // but seemingly, a 3x3 Sobel operator is used here (at least in
301 // later versions of the code), while a [1 -8 0 8 -1] kernel is
302 // used for all the derivatives in the variational refinement part
303 // (which borrows code from DeepFlow). This is inconsistent,
304 // but I guess we're better off with staying with the original
305 // decisions until we actually know having different ones would be better.
309 void exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height);
312 PersistentFBOSet<1> fbos;
315 GLuint sobel_program;
318 GLuint uniform_tex, uniform_image_size;
323 sobel_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
324 sobel_fs_obj = compile_shader(read_file("sobel.frag"), GL_FRAGMENT_SHADER);
325 sobel_program = link_program(sobel_vs_obj, sobel_fs_obj);
327 // Set up the VAO containing all the required position/texcoord data.
328 glCreateVertexArrays(1, &sobel_vao);
329 glBindVertexArray(sobel_vao);
331 GLint position_attrib = glGetAttribLocation(sobel_program, "position");
332 glEnableVertexArrayAttrib(sobel_vao, position_attrib);
333 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
335 uniform_tex = glGetUniformLocation(sobel_program, "tex");
338 void Sobel::exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height)
340 glUseProgram(sobel_program);
341 glBindTextureUnit(0, tex0_view);
342 glBindSampler(0, nearest_sampler);
343 glProgramUniform1i(sobel_program, uniform_tex, 0);
345 glViewport(0, 0, level_width, level_height);
346 fbos.render_to(grad0_tex);
347 glBindVertexArray(sobel_vao);
348 glUseProgram(sobel_program);
350 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
353 // Motion search to find the initial flow. See motion_search.frag for documentation.
357 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);
360 PersistentFBOSet<1> fbos;
362 GLuint motion_vs_obj;
363 GLuint motion_fs_obj;
364 GLuint motion_search_program;
365 GLuint motion_search_vao;
367 GLuint uniform_image_size, uniform_inv_image_size, uniform_inv_flow_size, uniform_inv_prev_level_size;
368 GLuint uniform_image0_tex, uniform_image1_tex, uniform_grad0_tex, uniform_flow_tex;
371 MotionSearch::MotionSearch()
373 motion_vs_obj = compile_shader(read_file("motion_search.vert"), GL_VERTEX_SHADER);
374 motion_fs_obj = compile_shader(read_file("motion_search.frag"), GL_FRAGMENT_SHADER);
375 motion_search_program = link_program(motion_vs_obj, motion_fs_obj);
377 // Set up the VAO containing all the required position/texcoord data.
378 glCreateVertexArrays(1, &motion_search_vao);
379 glBindVertexArray(motion_search_vao);
380 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
382 GLint position_attrib = glGetAttribLocation(motion_search_program, "position");
383 glEnableVertexArrayAttrib(motion_search_vao, position_attrib);
384 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
386 uniform_image_size = glGetUniformLocation(motion_search_program, "image_size");
387 uniform_inv_image_size = glGetUniformLocation(motion_search_program, "inv_image_size");
388 uniform_inv_flow_size = glGetUniformLocation(motion_search_program, "inv_flow_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_image_size, level_width, level_height);
406 glProgramUniform2f(motion_search_program, uniform_inv_image_size, 1.0f / level_width, 1.0f / level_height);
407 glProgramUniform2f(motion_search_program, uniform_inv_flow_size, 1.0f / width_patches, 1.0f / height_patches);
408 glProgramUniform2f(motion_search_program, uniform_inv_prev_level_size, 1.0f / prev_level_width, 1.0f / prev_level_height);
410 glViewport(0, 0, width_patches, height_patches);
411 fbos.render_to(flow_out_tex);
412 glBindVertexArray(motion_search_vao);
413 glUseProgram(motion_search_program);
414 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
417 // Do “densification”, ie., upsampling of the flow patches to the flow field
418 // (the same size as the image at this level). We draw one quad per patch
419 // over its entire covered area (using instancing in the vertex shader),
420 // and then weight the contributions in the pixel shader by post-warp difference.
421 // This is equation (3) in the paper.
423 // We accumulate the flow vectors in the R/G channels (for u/v) and the total
424 // weight in the B channel. Dividing R and G by B gives the normalized values.
428 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);
431 PersistentFBOSet<1> fbos;
433 GLuint densify_vs_obj;
434 GLuint densify_fs_obj;
435 GLuint densify_program;
438 GLuint uniform_width_patches, uniform_patch_size, uniform_patch_spacing;
439 GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex;
444 densify_vs_obj = compile_shader(read_file("densify.vert"), GL_VERTEX_SHADER);
445 densify_fs_obj = compile_shader(read_file("densify.frag"), GL_FRAGMENT_SHADER);
446 densify_program = link_program(densify_vs_obj, densify_fs_obj);
448 // Set up the VAO containing all the required position/texcoord data.
449 glCreateVertexArrays(1, &densify_vao);
450 glBindVertexArray(densify_vao);
451 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
453 GLint position_attrib = glGetAttribLocation(densify_program, "position");
454 glEnableVertexArrayAttrib(densify_vao, position_attrib);
455 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
457 uniform_width_patches = glGetUniformLocation(densify_program, "width_patches");
458 uniform_patch_size = glGetUniformLocation(densify_program, "patch_size");
459 uniform_patch_spacing = glGetUniformLocation(densify_program, "patch_spacing");
460 uniform_image0_tex = glGetUniformLocation(densify_program, "image0_tex");
461 uniform_image1_tex = glGetUniformLocation(densify_program, "image1_tex");
462 uniform_flow_tex = glGetUniformLocation(densify_program, "flow_tex");
465 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)
467 glUseProgram(densify_program);
469 bind_sampler(densify_program, uniform_image0_tex, 0, tex0_view, nearest_sampler);
470 bind_sampler(densify_program, uniform_image1_tex, 1, tex1_view, linear_sampler);
471 bind_sampler(densify_program, uniform_flow_tex, 2, flow_tex, nearest_sampler);
473 glProgramUniform1i(densify_program, uniform_width_patches, width_patches);
474 glProgramUniform2f(densify_program, uniform_patch_size,
475 float(patch_size_pixels) / level_width,
476 float(patch_size_pixels) / level_height);
478 float patch_spacing_x = float(level_width - patch_size_pixels) / (width_patches - 1);
479 float patch_spacing_y = float(level_height - patch_size_pixels) / (height_patches - 1);
480 if (width_patches == 1) patch_spacing_x = 0.0f; // Avoid infinities.
481 if (height_patches == 1) patch_spacing_y = 0.0f;
482 glProgramUniform2f(densify_program, uniform_patch_spacing,
483 patch_spacing_x / level_width,
484 patch_spacing_y / level_height);
486 glViewport(0, 0, level_width, level_height);
488 glBlendFunc(GL_ONE, GL_ONE);
489 glBindVertexArray(densify_vao);
490 fbos.render_to(dense_flow_tex);
491 glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width_patches * height_patches);
494 // Warp I_1 to I_w, and then compute the mean (I) and difference (I_t) of
495 // I_0 and I_w. The prewarping is what enables us to solve the variational
496 // flow for du,dv instead of u,v.
498 // Also calculates the normalized flow, ie. divides by z (this is needed because
499 // Densify works by additive blending) and multiplies by the image size.
501 // See variational_refinement.txt for more information.
505 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);
508 PersistentFBOSet<3> fbos;
510 GLuint prewarp_vs_obj;
511 GLuint prewarp_fs_obj;
512 GLuint prewarp_program;
515 GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex;
516 GLuint uniform_image_size;
521 prewarp_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
522 prewarp_fs_obj = compile_shader(read_file("prewarp.frag"), GL_FRAGMENT_SHADER);
523 prewarp_program = link_program(prewarp_vs_obj, prewarp_fs_obj);
525 // Set up the VAO containing all the required position/texcoord data.
526 glCreateVertexArrays(1, &prewarp_vao);
527 glBindVertexArray(prewarp_vao);
528 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
530 GLint position_attrib = glGetAttribLocation(prewarp_program, "position");
531 glEnableVertexArrayAttrib(prewarp_vao, position_attrib);
532 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
534 uniform_image0_tex = glGetUniformLocation(prewarp_program, "image0_tex");
535 uniform_image1_tex = glGetUniformLocation(prewarp_program, "image1_tex");
536 uniform_flow_tex = glGetUniformLocation(prewarp_program, "flow_tex");
538 uniform_image_size = glGetUniformLocation(prewarp_program, "image_size");
541 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)
543 glUseProgram(prewarp_program);
545 bind_sampler(prewarp_program, uniform_image0_tex, 0, tex0_view, nearest_sampler);
546 bind_sampler(prewarp_program, uniform_image1_tex, 1, tex1_view, linear_sampler);
547 bind_sampler(prewarp_program, uniform_flow_tex, 2, flow_tex, nearest_sampler);
549 glProgramUniform2f(prewarp_program, uniform_image_size, level_width, level_height);
551 glViewport(0, 0, level_width, level_height);
553 glBindVertexArray(prewarp_vao);
554 fbos.render_to(I_tex, I_t_tex, normalized_flow_tex);
555 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
558 // From I, calculate the partial derivatives I_x and I_y. We use a four-tap
559 // central difference filter, since apparently, that's tradition (I haven't
560 // measured quality versus a more normal 0.5 (I[x+1] - I[x-1]).)
561 // The coefficients come from
563 // https://en.wikipedia.org/wiki/Finite_difference_coefficient
565 // Also computes β_0, since it depends only on I_x and I_y.
569 void exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, int level_width, int level_height);
572 PersistentFBOSet<2> fbos;
574 GLuint derivatives_vs_obj;
575 GLuint derivatives_fs_obj;
576 GLuint derivatives_program;
577 GLuint derivatives_vao;
582 Derivatives::Derivatives()
584 derivatives_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
585 derivatives_fs_obj = compile_shader(read_file("derivatives.frag"), GL_FRAGMENT_SHADER);
586 derivatives_program = link_program(derivatives_vs_obj, derivatives_fs_obj);
588 // Set up the VAO containing all the required position/texcoord data.
589 glCreateVertexArrays(1, &derivatives_vao);
590 glBindVertexArray(derivatives_vao);
591 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
593 GLint position_attrib = glGetAttribLocation(derivatives_program, "position");
594 glEnableVertexArrayAttrib(derivatives_vao, position_attrib);
595 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
597 uniform_tex = glGetUniformLocation(derivatives_program, "tex");
600 void Derivatives::exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, int level_width, int level_height)
602 glUseProgram(derivatives_program);
604 bind_sampler(derivatives_program, uniform_tex, 0, input_tex, nearest_sampler);
606 glViewport(0, 0, level_width, level_height);
608 glBindVertexArray(derivatives_vao);
609 fbos.render_to(I_x_y_tex, beta_0_tex);
610 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
613 // Calculate the smoothness constraints between neighboring pixels;
614 // s_x(x,y) stores smoothness between pixel (x,y) and (x+1,y),
615 // and s_y(x,y) stores between (x,y) and (x,y+1). We'll sample with
616 // border color (0,0) later, so that there's zero diffusion out of
619 // See variational_refinement.txt for more information.
620 class ComputeSmoothness {
623 void exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height);
626 PersistentFBOSet<2> fbos;
628 GLuint smoothness_vs_obj;
629 GLuint smoothness_fs_obj;
630 GLuint smoothness_program;
631 GLuint smoothness_vao;
633 GLuint uniform_flow_tex, uniform_diff_flow_tex;
634 GLuint uniform_alpha;
637 ComputeSmoothness::ComputeSmoothness()
639 smoothness_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
640 smoothness_fs_obj = compile_shader(read_file("smoothness.frag"), GL_FRAGMENT_SHADER);
641 smoothness_program = link_program(smoothness_vs_obj, smoothness_fs_obj);
643 // Set up the VAO containing all the required position/texcoord data.
644 glCreateVertexArrays(1, &smoothness_vao);
645 glBindVertexArray(smoothness_vao);
646 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
648 GLint position_attrib = glGetAttribLocation(smoothness_program, "position");
649 glEnableVertexArrayAttrib(smoothness_vao, position_attrib);
650 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
652 uniform_flow_tex = glGetUniformLocation(smoothness_program, "flow_tex");
653 uniform_diff_flow_tex = glGetUniformLocation(smoothness_program, "diff_flow_tex");
654 uniform_alpha = glGetUniformLocation(smoothness_program, "alpha");
657 void ComputeSmoothness::exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height)
659 glUseProgram(smoothness_program);
661 bind_sampler(smoothness_program, uniform_flow_tex, 0, flow_tex, nearest_sampler);
662 bind_sampler(smoothness_program, uniform_diff_flow_tex, 1, diff_flow_tex, nearest_sampler);
663 glProgramUniform1f(smoothness_program, uniform_alpha, vr_alpha);
665 glViewport(0, 0, level_width, level_height);
668 glBindVertexArray(smoothness_vao);
669 fbos.render_to(smoothness_x_tex, smoothness_y_tex);
670 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
672 // Make sure the smoothness on the right and upper borders is zero.
673 // We could have done this by making (W-1)xH and Wx(H-1) textures instead
674 // (we're sampling smoothness with all-zero border color), but we'd
675 // have to adjust the sampling coordinates, which is annoying.
676 glClearTexSubImage(smoothness_x_tex, 0, level_width - 1, 0, 0, 1, level_height, 1, GL_RED, GL_FLOAT, nullptr);
677 glClearTexSubImage(smoothness_y_tex, 0, 0, level_height - 1, 0, level_width, 1, 1, GL_RED, GL_FLOAT, nullptr);
680 // Set up the equations set (two equations in two unknowns, per pixel).
681 // We store five floats; the three non-redundant elements of the 2x2 matrix (A)
682 // as 32-bit floats, and the two elements on the right-hand side (b) as 16-bit
683 // floats. (Actually, we store the inverse of the diagonal elements, because
684 // we only ever need to divide by them.) This fits into four u32 values;
685 // R, G, B for the matrix (the last element is symmetric) and A for the two b values.
686 // All the values of the energy term (E_I, E_G, E_S), except the smoothness
687 // terms that depend on other pixels, are calculated in one pass.
689 // See variational_refinement.txt for more information.
690 class SetupEquations {
693 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);
696 PersistentFBOSet<1> fbos;
698 GLuint equations_vs_obj;
699 GLuint equations_fs_obj;
700 GLuint equations_program;
701 GLuint equations_vao;
703 GLuint uniform_I_x_y_tex, uniform_I_t_tex;
704 GLuint uniform_diff_flow_tex, uniform_base_flow_tex;
705 GLuint uniform_beta_0_tex;
706 GLuint uniform_smoothness_x_tex, uniform_smoothness_y_tex;
707 GLuint uniform_gamma, uniform_delta;
710 SetupEquations::SetupEquations()
712 equations_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
713 equations_fs_obj = compile_shader(read_file("equations.frag"), GL_FRAGMENT_SHADER);
714 equations_program = link_program(equations_vs_obj, equations_fs_obj);
716 // Set up the VAO containing all the required position/texcoord data.
717 glCreateVertexArrays(1, &equations_vao);
718 glBindVertexArray(equations_vao);
719 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
721 GLint position_attrib = glGetAttribLocation(equations_program, "position");
722 glEnableVertexArrayAttrib(equations_vao, position_attrib);
723 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
725 uniform_I_x_y_tex = glGetUniformLocation(equations_program, "I_x_y_tex");
726 uniform_I_t_tex = glGetUniformLocation(equations_program, "I_t_tex");
727 uniform_diff_flow_tex = glGetUniformLocation(equations_program, "diff_flow_tex");
728 uniform_base_flow_tex = glGetUniformLocation(equations_program, "base_flow_tex");
729 uniform_beta_0_tex = glGetUniformLocation(equations_program, "beta_0_tex");
730 uniform_smoothness_x_tex = glGetUniformLocation(equations_program, "smoothness_x_tex");
731 uniform_smoothness_y_tex = glGetUniformLocation(equations_program, "smoothness_y_tex");
732 uniform_gamma = glGetUniformLocation(equations_program, "gamma");
733 uniform_delta = glGetUniformLocation(equations_program, "delta");
736 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)
738 glUseProgram(equations_program);
740 bind_sampler(equations_program, uniform_I_x_y_tex, 0, I_x_y_tex, nearest_sampler);
741 bind_sampler(equations_program, uniform_I_t_tex, 1, I_t_tex, nearest_sampler);
742 bind_sampler(equations_program, uniform_diff_flow_tex, 2, diff_flow_tex, nearest_sampler);
743 bind_sampler(equations_program, uniform_base_flow_tex, 3, base_flow_tex, nearest_sampler);
744 bind_sampler(equations_program, uniform_beta_0_tex, 4, beta_0_tex, nearest_sampler);
745 bind_sampler(equations_program, uniform_smoothness_x_tex, 5, smoothness_x_tex, zero_border_sampler);
746 bind_sampler(equations_program, uniform_smoothness_y_tex, 6, smoothness_y_tex, zero_border_sampler);
747 glProgramUniform1f(equations_program, uniform_delta, vr_delta);
748 glProgramUniform1f(equations_program, uniform_gamma, vr_gamma);
750 glViewport(0, 0, level_width, level_height);
752 glBindVertexArray(equations_vao);
753 fbos.render_to(equation_tex);
754 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
757 // Actually solve the equation sets made by SetupEquations, by means of
758 // successive over-relaxation (SOR).
760 // See variational_refinement.txt for more information.
764 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);
767 PersistentFBOSet<1> fbos;
774 GLuint uniform_diff_flow_tex;
775 GLuint uniform_equation_tex;
776 GLuint uniform_smoothness_x_tex, uniform_smoothness_y_tex;
781 sor_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
782 sor_fs_obj = compile_shader(read_file("sor.frag"), GL_FRAGMENT_SHADER);
783 sor_program = link_program(sor_vs_obj, sor_fs_obj);
785 // Set up the VAO containing all the required position/texcoord data.
786 glCreateVertexArrays(1, &sor_vao);
787 glBindVertexArray(sor_vao);
788 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
790 GLint position_attrib = glGetAttribLocation(sor_program, "position");
791 glEnableVertexArrayAttrib(sor_vao, position_attrib);
792 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
794 uniform_diff_flow_tex = glGetUniformLocation(sor_program, "diff_flow_tex");
795 uniform_equation_tex = glGetUniformLocation(sor_program, "equation_tex");
796 uniform_smoothness_x_tex = glGetUniformLocation(sor_program, "smoothness_x_tex");
797 uniform_smoothness_y_tex = glGetUniformLocation(sor_program, "smoothness_y_tex");
800 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)
802 glUseProgram(sor_program);
804 bind_sampler(sor_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler);
805 bind_sampler(sor_program, uniform_smoothness_x_tex, 1, smoothness_x_tex, zero_border_sampler);
806 bind_sampler(sor_program, uniform_smoothness_y_tex, 2, smoothness_y_tex, zero_border_sampler);
807 bind_sampler(sor_program, uniform_equation_tex, 3, equation_tex, nearest_sampler);
809 glViewport(0, 0, level_width, level_height);
811 glBindVertexArray(sor_vao);
812 fbos.render_to(diff_flow_tex); // NOTE: Bind to same as we render from!
814 for (int i = 0; i < num_iterations; ++i) {
815 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
816 if (i != num_iterations - 1) {
822 // Simply add the differential flow found by the variational refinement to the base flow.
823 // The output is in base_flow_tex; we don't need to make a new texture.
827 void exec(GLuint base_flow_tex, GLuint diff_flow_tex, int level_width, int level_height);
830 PersistentFBOSet<1> fbos;
832 GLuint add_flow_vs_obj;
833 GLuint add_flow_fs_obj;
834 GLuint add_flow_program;
837 GLuint uniform_diff_flow_tex;
840 AddBaseFlow::AddBaseFlow()
842 add_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
843 add_flow_fs_obj = compile_shader(read_file("add_base_flow.frag"), GL_FRAGMENT_SHADER);
844 add_flow_program = link_program(add_flow_vs_obj, add_flow_fs_obj);
846 // Set up the VAO containing all the required position/texcoord data.
847 glCreateVertexArrays(1, &add_flow_vao);
848 glBindVertexArray(add_flow_vao);
849 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
851 GLint position_attrib = glGetAttribLocation(add_flow_program, "position");
852 glEnableVertexArrayAttrib(add_flow_vao, position_attrib);
853 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
855 uniform_diff_flow_tex = glGetUniformLocation(add_flow_program, "diff_flow_tex");
858 void AddBaseFlow::exec(GLuint base_flow_tex, GLuint diff_flow_tex, int level_width, int level_height)
860 glUseProgram(add_flow_program);
862 bind_sampler(add_flow_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler);
864 glViewport(0, 0, level_width, level_height);
866 glBlendFunc(GL_ONE, GL_ONE);
867 glBindVertexArray(add_flow_vao);
868 fbos.render_to(base_flow_tex);
870 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
873 // Take a copy of the flow, bilinearly interpolated and scaled up.
877 void exec(GLuint in_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height);
880 PersistentFBOSet<1> fbos;
882 GLuint resize_flow_vs_obj;
883 GLuint resize_flow_fs_obj;
884 GLuint resize_flow_program;
885 GLuint resize_flow_vao;
887 GLuint uniform_flow_tex;
888 GLuint uniform_scale_factor;
891 ResizeFlow::ResizeFlow()
893 resize_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
894 resize_flow_fs_obj = compile_shader(read_file("resize_flow.frag"), GL_FRAGMENT_SHADER);
895 resize_flow_program = link_program(resize_flow_vs_obj, resize_flow_fs_obj);
897 // Set up the VAO containing all the required position/texcoord data.
898 glCreateVertexArrays(1, &resize_flow_vao);
899 glBindVertexArray(resize_flow_vao);
900 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
902 GLint position_attrib = glGetAttribLocation(resize_flow_program, "position");
903 glEnableVertexArrayAttrib(resize_flow_vao, position_attrib);
904 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
906 uniform_flow_tex = glGetUniformLocation(resize_flow_program, "flow_tex");
907 uniform_scale_factor = glGetUniformLocation(resize_flow_program, "scale_factor");
910 void ResizeFlow::exec(GLuint flow_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height)
912 glUseProgram(resize_flow_program);
914 bind_sampler(resize_flow_program, uniform_flow_tex, 0, flow_tex, nearest_sampler);
916 glProgramUniform2f(resize_flow_program, uniform_scale_factor, float(output_width) / input_width, float(output_height) / input_height);
918 glViewport(0, 0, output_width, output_height);
920 glBindVertexArray(resize_flow_vao);
921 fbos.render_to(out_tex);
923 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
929 pair<GLuint, GLuint> begin_timer(const string &name, int level);
935 pair<GLuint, GLuint> query;
937 vector<Timer> timers;
940 pair<GLuint, GLuint> GPUTimers::begin_timer(const string &name, int level)
942 if (!enable_timing) {
943 return make_pair(0, 0);
947 glGenQueries(2, queries);
948 glQueryCounter(queries[0], GL_TIMESTAMP);
953 timer.query.first = queries[0];
954 timer.query.second = queries[1];
955 timers.push_back(timer);
959 void GPUTimers::print()
961 for (const Timer &timer : timers) {
962 // NOTE: This makes the CPU wait for the GPU.
963 GLuint64 time_start, time_end;
964 glGetQueryObjectui64v(timer.query.first, GL_QUERY_RESULT, &time_start);
965 glGetQueryObjectui64v(timer.query.second, GL_QUERY_RESULT, &time_end);
966 //fprintf(stderr, "GPU time used = %.1f ms\n", time_elapsed / 1e6);
967 for (int i = 0; i < timer.level * 2; ++i) {
968 fprintf(stderr, " ");
970 fprintf(stderr, "%-30s %4.1f ms\n", timer.name.c_str(), GLint64(time_end - time_start) / 1e6);
974 // A simple RAII class for timing until the end of the scope.
977 ScopedTimer(const string &name, GPUTimers *timers)
978 : timers(timers), level(0)
980 query = timers->begin_timer(name, level);
983 ScopedTimer(const string &name, ScopedTimer *parent_timer)
984 : timers(parent_timer->timers),
985 level(parent_timer->level + 1)
987 query = timers->begin_timer(name, level);
997 if (enable_timing && !ended) {
998 glQueryCounter(query.second, GL_TIMESTAMP);
1006 pair<GLuint, GLuint> query;
1010 class DISComputeFlow {
1012 DISComputeFlow(int width, int height);
1014 // Returns a texture that must be released with release_texture()
1016 GLuint exec(GLuint tex0, GLuint tex1);
1017 void release_texture(GLuint tex);
1021 GLuint initial_flow_tex;
1023 // The various passes.
1025 MotionSearch motion_search;
1028 Derivatives derivatives;
1029 ComputeSmoothness compute_smoothness;
1030 SetupEquations setup_equations;
1032 AddBaseFlow add_base_flow;
1033 ResizeFlow resize_flow;
1038 GLuint width, height;
1039 bool in_use = false;
1041 vector<Texture> textures;
1043 GLuint get_texture(GLenum format, GLuint width, GLuint height);
1046 DISComputeFlow::DISComputeFlow(int width, int height)
1047 : width(width), height(height)
1049 // Make some samplers.
1050 glCreateSamplers(1, &nearest_sampler);
1051 glSamplerParameteri(nearest_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
1052 glSamplerParameteri(nearest_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
1053 glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
1054 glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
1056 glCreateSamplers(1, &linear_sampler);
1057 glSamplerParameteri(linear_sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
1058 glSamplerParameteri(linear_sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
1059 glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
1060 glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
1062 // The smoothness is sampled so that once we get to a smoothness involving
1063 // a value outside the border, the diffusivity between the two becomes zero.
1064 // Similarly, gradients are zero outside the border, since the edge is taken
1066 glCreateSamplers(1, &zero_border_sampler);
1067 glSamplerParameteri(zero_border_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
1068 glSamplerParameteri(zero_border_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
1069 glSamplerParameteri(zero_border_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
1070 glSamplerParameteri(zero_border_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
1071 float zero[] = { 0.0f, 0.0f, 0.0f, 0.0f };
1072 glSamplerParameterfv(zero_border_sampler, GL_TEXTURE_BORDER_COLOR, zero);
1074 // Initial flow is zero, 1x1.
1075 glCreateTextures(GL_TEXTURE_2D, 1, &initial_flow_tex);
1076 glTextureStorage2D(initial_flow_tex, 1, GL_RG16F, 1, 1);
1077 glClearTexImage(initial_flow_tex, 0, GL_RG, GL_FLOAT, nullptr);
1080 GLuint DISComputeFlow::exec(GLuint tex0, GLuint tex1)
1082 for (const Texture &tex : textures) {
1083 assert(!tex.in_use);
1086 int prev_level_width = 1, prev_level_height = 1;
1087 GLuint prev_level_flow_tex = initial_flow_tex;
1091 ScopedTimer total_timer("Total", &timers);
1092 for (int level = coarsest_level; level >= int(finest_level); --level) {
1093 char timer_name[256];
1094 snprintf(timer_name, sizeof(timer_name), "Level %d", level);
1095 ScopedTimer level_timer(timer_name, &total_timer);
1097 int level_width = width >> level;
1098 int level_height = height >> level;
1099 float patch_spacing_pixels = patch_size_pixels * (1.0f - patch_overlap_ratio);
1100 int width_patches = 1 + lrintf((level_width - patch_size_pixels) / patch_spacing_pixels);
1101 int height_patches = 1 + lrintf((level_height - patch_size_pixels) / patch_spacing_pixels);
1103 // Make sure we always read from the correct level; the chosen
1104 // mipmapping could otherwise be rather unpredictable, especially
1105 // during motion search.
1106 // TODO: create these beforehand, and stop leaking them.
1107 GLuint tex0_view, tex1_view;
1108 glGenTextures(1, &tex0_view);
1109 glTextureView(tex0_view, GL_TEXTURE_2D, tex0, GL_R8, level, 1, 0, 1);
1110 glGenTextures(1, &tex1_view);
1111 glTextureView(tex1_view, GL_TEXTURE_2D, tex1, GL_R8, level, 1, 0, 1);
1113 // Create a new texture; we could be fancy and render use a multi-level
1114 // texture, but meh.
1115 GLuint grad0_tex = get_texture(GL_RG16F, level_width, level_height);
1117 // Find the derivative.
1119 ScopedTimer timer("Sobel", &level_timer);
1120 sobel.exec(tex0_view, grad0_tex, level_width, level_height);
1123 // Motion search to find the initial flow. We use the flow from the previous
1124 // level (sampled bilinearly; no fancy tricks) as a guide, then search from there.
1126 // Create an output flow texture.
1127 GLuint flow_out_tex = get_texture(GL_RGB16F, width_patches, height_patches);
1131 ScopedTimer timer("Motion search", &level_timer);
1132 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);
1134 release_texture(grad0_tex);
1138 // Set up an output texture (initially zero).
1139 GLuint dense_flow_tex = get_texture(GL_RGB16F, level_width, level_height);
1140 glClearTexImage(dense_flow_tex, 0, GL_RGB, GL_FLOAT, nullptr);
1144 ScopedTimer timer("Densification", &level_timer);
1145 densify.exec(tex0_view, tex1_view, flow_out_tex, dense_flow_tex, level_width, level_height, width_patches, height_patches);
1147 release_texture(flow_out_tex);
1149 // Everything below here in the loop belongs to variational refinement.
1150 ScopedTimer varref_timer("Variational refinement", &level_timer);
1152 // Prewarping; create I and I_t, and a normalized base flow (so we don't
1153 // have to normalize it over and over again, and also save some bandwidth).
1155 // During the entire rest of the variational refinement, flow will be measured
1156 // in pixels, not 0..1 normalized OpenGL texture coordinates.
1157 // This is because variational refinement depends so heavily on derivatives,
1158 // which are measured in intensity levels per pixel.
1159 GLuint I_tex = get_texture(GL_R16F, level_width, level_height);
1160 GLuint I_t_tex = get_texture(GL_R16F, level_width, level_height);
1161 GLuint base_flow_tex = get_texture(GL_RG16F, level_width, level_height);
1163 ScopedTimer timer("Prewarping", &varref_timer);
1164 prewarp.exec(tex0_view, tex1_view, dense_flow_tex, I_tex, I_t_tex, base_flow_tex, level_width, level_height);
1166 release_texture(dense_flow_tex);
1168 // Calculate I_x and I_y. We're only calculating first derivatives;
1169 // the others will be taken on-the-fly in order to sample from fewer
1170 // textures overall, since sampling from the L1 cache is cheap.
1171 // (TODO: Verify that this is indeed faster than making separate
1172 // double-derivative textures.)
1173 GLuint I_x_y_tex = get_texture(GL_RG16F, level_width, level_height);
1174 GLuint beta_0_tex = get_texture(GL_R16F, level_width, level_height);
1176 ScopedTimer timer("First derivatives", &varref_timer);
1177 derivatives.exec(I_tex, I_x_y_tex, beta_0_tex, level_width, level_height);
1179 release_texture(I_tex);
1181 // We need somewhere to store du and dv (the flow increment, relative
1182 // to the non-refined base flow u0 and v0). It starts at zero.
1183 GLuint du_dv_tex = get_texture(GL_RG16F, level_width, level_height);
1184 glClearTexImage(du_dv_tex, 0, GL_RG, GL_FLOAT, nullptr);
1186 // And for smoothness.
1187 GLuint smoothness_x_tex = get_texture(GL_R16F, level_width, level_height);
1188 GLuint smoothness_y_tex = get_texture(GL_R16F, level_width, level_height);
1190 // And finally for the equation set. See SetupEquations for
1191 // the storage format.
1192 GLuint equation_tex = get_texture(GL_RGBA32UI, level_width, level_height);
1194 for (int outer_idx = 0; outer_idx < level + 1; ++outer_idx) {
1195 // Calculate the smoothness terms between the neighboring pixels,
1196 // both in x and y direction.
1198 ScopedTimer timer("Compute smoothness", &varref_timer);
1199 compute_smoothness.exec(base_flow_tex, du_dv_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height);
1202 // Set up the 2x2 equation system for each pixel.
1204 ScopedTimer timer("Set up equations", &varref_timer);
1205 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);
1208 // Run a few SOR (or quasi-SOR, since we're not really Jacobi) iterations.
1209 // Note that these are to/from the same texture.
1211 ScopedTimer timer("SOR", &varref_timer);
1212 sor.exec(du_dv_tex, equation_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height, 5);
1216 release_texture(I_t_tex);
1217 release_texture(I_x_y_tex);
1218 release_texture(beta_0_tex);
1219 release_texture(smoothness_x_tex);
1220 release_texture(smoothness_y_tex);
1221 release_texture(equation_tex);
1223 // Add the differential flow found by the variational refinement to the base flow,
1224 // giving the final flow estimate for this level.
1225 // The output is in diff_flow_tex; we don't need to make a new texture.
1227 // Disabling this doesn't save any time (although we could easily make it so that
1228 // it is more efficient), but it helps debug the motion search.
1229 if (enable_variational_refinement) {
1230 ScopedTimer timer("Add differential flow", &varref_timer);
1231 add_base_flow.exec(base_flow_tex, du_dv_tex, level_width, level_height);
1233 release_texture(du_dv_tex);
1235 if (prev_level_flow_tex != initial_flow_tex) {
1236 release_texture(prev_level_flow_tex);
1238 prev_level_flow_tex = base_flow_tex;
1239 prev_level_width = level_width;
1240 prev_level_height = level_height;
1246 // Scale up the flow to the final size (if needed).
1247 if (finest_level == 0) {
1248 return prev_level_flow_tex;
1250 GLuint final_tex = get_texture(GL_RG16F, width, height);
1251 resize_flow.exec(prev_level_flow_tex, final_tex, prev_level_width, prev_level_height, width, height);
1252 release_texture(prev_level_flow_tex);
1257 GLuint DISComputeFlow::get_texture(GLenum format, GLuint width, GLuint height)
1259 for (Texture &tex : textures) {
1260 if (!tex.in_use && tex.format == format &&
1261 tex.width == width && tex.height == height) {
1268 glCreateTextures(GL_TEXTURE_2D, 1, &tex.tex_num);
1269 glTextureStorage2D(tex.tex_num, 1, format, width, height);
1270 tex.format = format;
1272 tex.height = height;
1274 textures.push_back(tex);
1278 void DISComputeFlow::release_texture(GLuint tex_num)
1280 for (Texture &tex : textures) {
1281 if (tex.tex_num == tex_num) {
1290 // OpenGL uses a bottom-left coordinate system, .flo files use a top-left coordinate system.
1291 void flip_coordinate_system(float *dense_flow, unsigned width, unsigned height)
1293 for (unsigned i = 0; i < width * height; ++i) {
1294 dense_flow[i * 2 + 1] = -dense_flow[i * 2 + 1];
1298 void write_flow(const char *filename, const float *dense_flow, unsigned width, unsigned height)
1300 FILE *flowfp = fopen(filename, "wb");
1301 fprintf(flowfp, "FEIH");
1302 fwrite(&width, 4, 1, flowfp);
1303 fwrite(&height, 4, 1, flowfp);
1304 for (unsigned y = 0; y < height; ++y) {
1305 int yy = height - y - 1;
1306 fwrite(&dense_flow[yy * width * 2], width * 2 * sizeof(float), 1, flowfp);
1311 void write_ppm(const char *filename, const float *dense_flow, unsigned width, unsigned height)
1313 FILE *fp = fopen(filename, "wb");
1314 fprintf(fp, "P6\n%d %d\n255\n", width, height);
1315 for (unsigned y = 0; y < unsigned(height); ++y) {
1316 int yy = height - y - 1;
1317 for (unsigned x = 0; x < unsigned(width); ++x) {
1318 float du = dense_flow[(yy * width + x) * 2 + 0];
1319 float dv = dense_flow[(yy * width + x) * 2 + 1];
1322 flow2rgb(du, dv, &r, &g, &b);
1331 void finish_one_read(GLuint width, GLuint height)
1333 assert(!reads_in_progress.empty());
1334 ReadInProgress read = reads_in_progress.front();
1335 reads_in_progress.pop_front();
1337 unique_ptr<float[]> flow(new float[width * height * 2]);
1338 void *buf = glMapNamedBufferRange(read.pbo, 0, width * height * 2 * sizeof(float), GL_MAP_READ_BIT); // Blocks if the read isn't done yet.
1339 memcpy(flow.get(), buf, width * height * 2 * sizeof(float));
1340 glUnmapNamedBuffer(read.pbo);
1341 spare_pbos.push(read.pbo);
1343 flip_coordinate_system(flow.get(), width, height);
1344 if (!read.flow_filename.empty()) {
1345 write_flow(read.flow_filename.c_str(), flow.get(), width, height);
1346 fprintf(stderr, "%s %s -> %s\n", read.filename0.c_str(), read.filename1.c_str(), read.flow_filename.c_str());
1348 if (!read.ppm_filename.empty()) {
1349 write_ppm(read.ppm_filename.c_str(), flow.get(), width, height);
1353 void schedule_read(GLuint tex, GLuint width, GLuint height, const char *filename0, const char *filename1, const char *flow_filename, const char *ppm_filename)
1355 if (spare_pbos.empty()) {
1356 finish_one_read(width, height);
1358 assert(!spare_pbos.empty());
1359 reads_in_progress.emplace_back(ReadInProgress{ spare_pbos.top(), filename0, filename1, flow_filename, ppm_filename });
1360 glBindBuffer(GL_PIXEL_PACK_BUFFER, spare_pbos.top());
1362 glGetTextureImage(tex, 0, GL_RG, GL_FLOAT, width * height * 2 * sizeof(float), nullptr);
1363 glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
1366 int main(int argc, char **argv)
1368 static const option long_options[] = {
1369 { "smoothness-relative-weight", required_argument, 0, 's' }, // alpha.
1370 { "intensity-relative-weight", required_argument, 0, 'i' }, // delta.
1371 { "gradient-relative-weight", required_argument, 0, 'g' }, // gamma.
1372 { "disable-timing", no_argument, 0, 1000 },
1373 { "ignore-variational-refinement", no_argument, 0, 1001 } // Still calculates it, just doesn't apply it.
1377 int option_index = 0;
1378 int c = getopt_long(argc, argv, "s:i:g:", long_options, &option_index);
1385 vr_alpha = atof(optarg);
1388 vr_delta = atof(optarg);
1391 vr_gamma = atof(optarg);
1394 enable_timing = false;
1397 enable_variational_refinement = false;
1400 fprintf(stderr, "Unknown option '%s'\n", argv[option_index]);
1405 if (SDL_Init(SDL_INIT_EVERYTHING) == -1) {
1406 fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError());
1409 SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
1410 SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0);
1411 SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0);
1412 SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
1414 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
1415 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
1416 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 5);
1417 // SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
1418 SDL_Window *window = SDL_CreateWindow("OpenGL window",
1419 SDL_WINDOWPOS_UNDEFINED,
1420 SDL_WINDOWPOS_UNDEFINED,
1423 SDL_GLContext context = SDL_GL_CreateContext(window);
1424 assert(context != nullptr);
1426 const char *filename0 = argc >= (optind + 1) ? argv[optind] : "test1499.png";
1427 const char *filename1 = argc >= (optind + 2) ? argv[optind + 1] : "test1500.png";
1428 const char *flow_filename = argc >= (optind + 3) ? argv[optind + 2] : "flow.flo";
1431 unsigned width1, height1, width2, height2;
1432 GLuint tex0 = load_texture(filename0, &width1, &height1);
1433 GLuint tex1 = load_texture(filename1, &width2, &height2);
1435 if (width1 != width2 || height1 != height2) {
1436 fprintf(stderr, "Image dimensions don't match (%dx%d versus %dx%d)\n",
1437 width1, height1, width2, height2);
1441 // Set up some PBOs to do asynchronous readback.
1443 glCreateBuffers(5, pbos);
1444 for (int i = 0; i < 5; ++i) {
1445 glNamedBufferData(pbos[i], width1 * height1 * 2 * sizeof(float), nullptr, GL_STREAM_READ);
1446 spare_pbos.push(pbos[i]);
1449 // FIXME: Should be part of DISComputeFlow (but needs to be initialized
1450 // before all the render passes).
1451 float vertices[] = {
1457 glCreateBuffers(1, &vertex_vbo);
1458 glNamedBufferData(vertex_vbo, sizeof(vertices), vertices, GL_STATIC_DRAW);
1459 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
1461 DISComputeFlow compute_flow(width1, height1);
1462 GLuint final_tex = compute_flow.exec(tex0, tex1);
1464 schedule_read(final_tex, width1, height1, filename0, filename1, flow_filename, "flow.ppm");
1465 compute_flow.release_texture(final_tex);
1467 // See if there are more flows on the command line (ie., more than three arguments),
1468 // and if so, process them.
1469 int num_flows = (argc - optind) / 3;
1470 for (int i = 1; i < num_flows; ++i) {
1471 const char *filename0 = argv[optind + i * 3 + 0];
1472 const char *filename1 = argv[optind + i * 3 + 1];
1473 const char *flow_filename = argv[optind + i * 3 + 2];
1474 GLuint width, height;
1475 GLuint tex0 = load_texture(filename0, &width, &height);
1476 if (width != width1 || height != height1) {
1477 fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n",
1478 filename0, width, height, width1, height1);
1482 GLuint tex1 = load_texture(filename1, &width, &height);
1483 if (width != width1 || height != height1) {
1484 fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n",
1485 filename1, width, height, width1, height1);
1489 GLuint final_tex = compute_flow.exec(tex0, tex1);
1490 schedule_read(final_tex, width1, height1, filename0, filename1, flow_filename, "");
1491 compute_flow.release_texture(final_tex);
1494 while (!reads_in_progress.empty()) {
1495 finish_one_read(width1, height1);