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>
25 #define BUFFER_OFFSET(i) ((char *)nullptr + (i))
29 // Operating point 3 (10 Hz on CPU, excluding preprocessing).
30 constexpr float patch_overlap_ratio = 0.75f;
31 constexpr unsigned coarsest_level = 5;
32 constexpr unsigned finest_level = 1;
33 constexpr unsigned patch_size_pixels = 12;
35 // Weighting constants for the different parts of the variational refinement.
36 // These don't correspond 1:1 to the values given in the DIS paper,
37 // since we have different normalizations and ranges in some cases.
38 float vr_gamma = 10.0f, vr_delta = 5.0f, vr_alpha = 10.0f;
40 bool enable_timing = true;
42 // Some global OpenGL objects.
43 // TODO: These should really be part of DISComputeFlow.
44 GLuint nearest_sampler, linear_sampler, smoothness_sampler;
47 string read_file(const string &filename)
49 FILE *fp = fopen(filename.c_str(), "r");
51 perror(filename.c_str());
55 int ret = fseek(fp, 0, SEEK_END);
57 perror("fseek(SEEK_END)");
63 ret = fseek(fp, 0, SEEK_SET);
65 perror("fseek(SEEK_SET)");
71 ret = fread(&str[0], size, 1, fp);
77 fprintf(stderr, "Short read when trying to read %d bytes from %s\n",
78 size, filename.c_str());
87 GLuint compile_shader(const string &shader_src, GLenum type)
89 GLuint obj = glCreateShader(type);
90 const GLchar* source[] = { shader_src.data() };
91 const GLint length[] = { (GLint)shader_src.size() };
92 glShaderSource(obj, 1, source, length);
95 GLchar info_log[4096];
96 GLsizei log_length = sizeof(info_log) - 1;
97 glGetShaderInfoLog(obj, log_length, &log_length, info_log);
98 info_log[log_length] = 0;
99 if (strlen(info_log) > 0) {
100 fprintf(stderr, "Shader compile log: %s\n", info_log);
104 glGetShaderiv(obj, GL_COMPILE_STATUS, &status);
105 if (status == GL_FALSE) {
106 // Add some line numbers to easier identify compile errors.
107 string src_with_lines = "/* 1 */ ";
109 for (char ch : shader_src) {
110 src_with_lines.push_back(ch);
113 snprintf(buf, sizeof(buf), "/* %3zu */ ", ++lineno);
114 src_with_lines += buf;
118 fprintf(stderr, "Failed to compile shader:\n%s\n", src_with_lines.c_str());
125 GLuint load_texture(const char *filename, unsigned *width_ret, unsigned *height_ret)
127 SDL_Surface *surf = IMG_Load(filename);
128 if (surf == nullptr) {
129 fprintf(stderr, "IMG_Load(%s): %s\n", filename, IMG_GetError());
133 // For whatever reason, SDL doesn't support converting to YUV surfaces
134 // nor grayscale, so we'll do it (slowly) ourselves.
135 SDL_Surface *rgb_surf = SDL_ConvertSurfaceFormat(surf, SDL_PIXELFORMAT_RGBA8888, /*flags=*/0);
136 if (rgb_surf == nullptr) {
137 fprintf(stderr, "SDL_ConvertSurfaceFormat(%s): %s\n", filename, SDL_GetError());
141 SDL_FreeSurface(surf);
143 unsigned width = rgb_surf->w, height = rgb_surf->h;
144 const uint8_t *sptr = (uint8_t *)rgb_surf->pixels;
145 unique_ptr<uint8_t[]> pix(new uint8_t[width * height]);
147 // Extract the Y component, and convert to bottom-left origin.
148 for (unsigned y = 0; y < height; ++y) {
149 unsigned y2 = height - 1 - y;
150 for (unsigned x = 0; x < width; ++x) {
151 uint8_t r = sptr[(y2 * width + x) * 4 + 3];
152 uint8_t g = sptr[(y2 * width + x) * 4 + 2];
153 uint8_t b = sptr[(y2 * width + x) * 4 + 1];
156 pix[y * width + x] = lrintf(r * 0.2126f + g * 0.7152f + b * 0.0722f);
159 SDL_FreeSurface(rgb_surf);
162 for (int w = width, h = height; w > 1 || h > 1; ) {
169 glCreateTextures(GL_TEXTURE_2D, 1, &tex);
170 glTextureStorage2D(tex, levels, GL_R8, width, height);
171 glTextureSubImage2D(tex, 0, 0, 0, width, height, GL_RED, GL_UNSIGNED_BYTE, pix.get());
172 glGenerateTextureMipmap(tex);
175 *height_ret = height;
180 GLuint link_program(GLuint vs_obj, GLuint fs_obj)
182 GLuint program = glCreateProgram();
183 glAttachShader(program, vs_obj);
184 glAttachShader(program, fs_obj);
185 glLinkProgram(program);
187 glGetProgramiv(program, GL_LINK_STATUS, &success);
188 if (success == GL_FALSE) {
189 GLchar error_log[1024] = {0};
190 glGetProgramInfoLog(program, 1024, nullptr, error_log);
191 fprintf(stderr, "Error linking program: %s\n", error_log);
197 GLuint generate_vbo(GLint size, GLsizeiptr data_size, const GLvoid *data)
200 glCreateBuffers(1, &vbo);
201 glBufferData(GL_ARRAY_BUFFER, data_size, data, GL_STATIC_DRAW);
202 glNamedBufferData(vbo, data_size, data, GL_STATIC_DRAW);
206 GLuint fill_vertex_attribute(GLuint vao, GLuint glsl_program_num, const string &attribute_name, GLint size, GLenum type, GLsizeiptr data_size, const GLvoid *data)
208 int attrib = glGetAttribLocation(glsl_program_num, attribute_name.c_str());
213 GLuint vbo = generate_vbo(size, data_size, data);
215 glBindBuffer(GL_ARRAY_BUFFER, vbo);
216 glEnableVertexArrayAttrib(vao, attrib);
217 glVertexAttribPointer(attrib, size, type, GL_FALSE, 0, BUFFER_OFFSET(0));
218 glBindBuffer(GL_ARRAY_BUFFER, 0);
223 void bind_sampler(GLuint program, GLint location, GLuint texture_unit, GLuint tex, GLuint sampler)
225 if (location == -1) {
229 glBindTextureUnit(texture_unit, tex);
230 glBindSampler(texture_unit, sampler);
231 glProgramUniform1i(program, location, texture_unit);
234 // A class that caches FBOs that render to a given set of textures.
235 // It never frees anything, so it is only suitable for rendering to
236 // the same (small) set of textures over and over again.
237 template<size_t num_elements>
238 class PersistentFBOSet {
240 void render_to(const array<GLuint, num_elements> &textures);
242 // Convenience wrappers.
243 void render_to(GLuint texture0, enable_if<num_elements == 1> * = nullptr) {
244 render_to({{texture0}});
247 void render_to(GLuint texture0, GLuint texture1, enable_if<num_elements == 2> * = nullptr) {
248 render_to({{texture0, texture1}});
251 void render_to(GLuint texture0, GLuint texture1, GLuint texture2, enable_if<num_elements == 3> * = nullptr) {
252 render_to({{texture0, texture1, texture2}});
255 void render_to(GLuint texture0, GLuint texture1, GLuint texture2, GLuint texture3, enable_if<num_elements == 4> * = nullptr) {
256 render_to({{texture0, texture1, texture2, texture3}});
260 // TODO: Delete these on destruction.
261 map<array<GLuint, num_elements>, GLuint> fbos;
264 template<size_t num_elements>
265 void PersistentFBOSet<num_elements>::render_to(const array<GLuint, num_elements> &textures)
267 auto it = fbos.find(textures);
268 if (it != fbos.end()) {
269 glBindFramebuffer(GL_FRAMEBUFFER, it->second);
274 glCreateFramebuffers(1, &fbo);
275 GLenum bufs[num_elements];
276 for (size_t i = 0; i < num_elements; ++i) {
277 glNamedFramebufferTexture(fbo, GL_COLOR_ATTACHMENT0 + i, textures[i], 0);
278 bufs[i] = GL_COLOR_ATTACHMENT0 + i;
280 glNamedFramebufferDrawBuffers(fbo, num_elements, bufs);
282 fbos[textures] = fbo;
283 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
286 // Compute gradients in every point, used for the motion search.
287 // The DIS paper doesn't actually mention how these are computed,
288 // but seemingly, a 3x3 Sobel operator is used here (at least in
289 // later versions of the code), while a [1 -8 0 8 -1] kernel is
290 // used for all the derivatives in the variational refinement part
291 // (which borrows code from DeepFlow). This is inconsistent,
292 // but I guess we're better off with staying with the original
293 // decisions until we actually know having different ones would be better.
297 void exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height);
300 PersistentFBOSet<1> fbos;
303 GLuint sobel_program;
306 GLuint uniform_tex, uniform_image_size;
311 sobel_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
312 sobel_fs_obj = compile_shader(read_file("sobel.frag"), GL_FRAGMENT_SHADER);
313 sobel_program = link_program(sobel_vs_obj, sobel_fs_obj);
315 // Set up the VAO containing all the required position/texcoord data.
316 glCreateVertexArrays(1, &sobel_vao);
317 glBindVertexArray(sobel_vao);
319 GLint position_attrib = glGetAttribLocation(sobel_program, "position");
320 glEnableVertexArrayAttrib(sobel_vao, position_attrib);
321 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
323 uniform_tex = glGetUniformLocation(sobel_program, "tex");
326 void Sobel::exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height)
328 glUseProgram(sobel_program);
329 glBindTextureUnit(0, tex0_view);
330 glBindSampler(0, nearest_sampler);
331 glProgramUniform1i(sobel_program, uniform_tex, 0);
333 glViewport(0, 0, level_width, level_height);
334 fbos.render_to(grad0_tex);
335 glBindVertexArray(sobel_vao);
336 glUseProgram(sobel_program);
338 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
341 // Motion search to find the initial flow. See motion_search.frag for documentation.
345 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);
348 PersistentFBOSet<1> fbos;
350 GLuint motion_vs_obj;
351 GLuint motion_fs_obj;
352 GLuint motion_search_program;
353 GLuint motion_search_vao;
355 GLuint uniform_image_size, uniform_inv_image_size, uniform_inv_prev_level_size;
356 GLuint uniform_image0_tex, uniform_image1_tex, uniform_grad0_tex, uniform_flow_tex;
359 MotionSearch::MotionSearch()
361 motion_vs_obj = compile_shader(read_file("motion_search.vert"), GL_VERTEX_SHADER);
362 motion_fs_obj = compile_shader(read_file("motion_search.frag"), GL_FRAGMENT_SHADER);
363 motion_search_program = link_program(motion_vs_obj, motion_fs_obj);
365 // Set up the VAO containing all the required position/texcoord data.
366 glCreateVertexArrays(1, &motion_search_vao);
367 glBindVertexArray(motion_search_vao);
368 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
370 GLint position_attrib = glGetAttribLocation(motion_search_program, "position");
371 glEnableVertexArrayAttrib(motion_search_vao, position_attrib);
372 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
374 uniform_image_size = glGetUniformLocation(motion_search_program, "image_size");
375 uniform_inv_image_size = glGetUniformLocation(motion_search_program, "inv_image_size");
376 uniform_inv_prev_level_size = glGetUniformLocation(motion_search_program, "inv_prev_level_size");
377 uniform_image0_tex = glGetUniformLocation(motion_search_program, "image0_tex");
378 uniform_image1_tex = glGetUniformLocation(motion_search_program, "image1_tex");
379 uniform_grad0_tex = glGetUniformLocation(motion_search_program, "grad0_tex");
380 uniform_flow_tex = glGetUniformLocation(motion_search_program, "flow_tex");
383 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)
385 glUseProgram(motion_search_program);
387 bind_sampler(motion_search_program, uniform_image0_tex, 0, tex0_view, nearest_sampler);
388 bind_sampler(motion_search_program, uniform_image1_tex, 1, tex1_view, linear_sampler);
389 bind_sampler(motion_search_program, uniform_grad0_tex, 2, grad0_tex, nearest_sampler);
390 bind_sampler(motion_search_program, uniform_flow_tex, 3, flow_tex, linear_sampler);
392 glProgramUniform2f(motion_search_program, uniform_image_size, level_width, level_height);
393 glProgramUniform2f(motion_search_program, uniform_inv_image_size, 1.0f / level_width, 1.0f / level_height);
394 glProgramUniform2f(motion_search_program, uniform_inv_prev_level_size, 1.0f / prev_level_width, 1.0f / prev_level_height);
396 glViewport(0, 0, width_patches, height_patches);
397 fbos.render_to(flow_out_tex);
398 glBindVertexArray(motion_search_vao);
399 glUseProgram(motion_search_program);
400 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
403 // Do “densification”, ie., upsampling of the flow patches to the flow field
404 // (the same size as the image at this level). We draw one quad per patch
405 // over its entire covered area (using instancing in the vertex shader),
406 // and then weight the contributions in the pixel shader by post-warp difference.
407 // This is equation (3) in the paper.
409 // We accumulate the flow vectors in the R/G channels (for u/v) and the total
410 // weight in the B channel. Dividing R and G by B gives the normalized values.
414 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);
417 PersistentFBOSet<1> fbos;
419 GLuint densify_vs_obj;
420 GLuint densify_fs_obj;
421 GLuint densify_program;
424 GLuint uniform_width_patches, uniform_patch_size, uniform_patch_spacing;
425 GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex;
430 densify_vs_obj = compile_shader(read_file("densify.vert"), GL_VERTEX_SHADER);
431 densify_fs_obj = compile_shader(read_file("densify.frag"), GL_FRAGMENT_SHADER);
432 densify_program = link_program(densify_vs_obj, densify_fs_obj);
434 // Set up the VAO containing all the required position/texcoord data.
435 glCreateVertexArrays(1, &densify_vao);
436 glBindVertexArray(densify_vao);
437 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
439 GLint position_attrib = glGetAttribLocation(densify_program, "position");
440 glEnableVertexArrayAttrib(densify_vao, position_attrib);
441 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
443 uniform_width_patches = glGetUniformLocation(densify_program, "width_patches");
444 uniform_patch_size = glGetUniformLocation(densify_program, "patch_size");
445 uniform_patch_spacing = glGetUniformLocation(densify_program, "patch_spacing");
446 uniform_image0_tex = glGetUniformLocation(densify_program, "image0_tex");
447 uniform_image1_tex = glGetUniformLocation(densify_program, "image1_tex");
448 uniform_flow_tex = glGetUniformLocation(densify_program, "flow_tex");
451 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)
453 glUseProgram(densify_program);
455 bind_sampler(densify_program, uniform_image0_tex, 0, tex0_view, nearest_sampler);
456 bind_sampler(densify_program, uniform_image1_tex, 1, tex1_view, linear_sampler);
457 bind_sampler(densify_program, uniform_flow_tex, 2, flow_tex, nearest_sampler);
459 glProgramUniform1i(densify_program, uniform_width_patches, width_patches);
460 glProgramUniform2f(densify_program, uniform_patch_size,
461 float(patch_size_pixels) / level_width,
462 float(patch_size_pixels) / level_height);
464 float patch_spacing_x = float(level_width - patch_size_pixels) / (width_patches - 1);
465 float patch_spacing_y = float(level_height - patch_size_pixels) / (height_patches - 1);
466 if (width_patches == 1) patch_spacing_x = 0.0f; // Avoid infinities.
467 if (height_patches == 1) patch_spacing_y = 0.0f;
468 glProgramUniform2f(densify_program, uniform_patch_spacing,
469 patch_spacing_x / level_width,
470 patch_spacing_y / level_height);
472 glViewport(0, 0, level_width, level_height);
474 glBlendFunc(GL_ONE, GL_ONE);
475 glBindVertexArray(densify_vao);
476 fbos.render_to(dense_flow_tex);
477 glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width_patches * height_patches);
480 // Warp I_1 to I_w, and then compute the mean (I) and difference (I_t) of
481 // I_0 and I_w. The prewarping is what enables us to solve the variational
482 // flow for du,dv instead of u,v.
484 // Also calculates the normalized flow, ie. divides by z (this is needed because
485 // Densify works by additive blending) and multiplies by the image size.
487 // See variational_refinement.txt for more information.
491 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);
494 PersistentFBOSet<3> fbos;
496 GLuint prewarp_vs_obj;
497 GLuint prewarp_fs_obj;
498 GLuint prewarp_program;
501 GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex;
502 GLuint uniform_image_size;
507 prewarp_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
508 prewarp_fs_obj = compile_shader(read_file("prewarp.frag"), GL_FRAGMENT_SHADER);
509 prewarp_program = link_program(prewarp_vs_obj, prewarp_fs_obj);
511 // Set up the VAO containing all the required position/texcoord data.
512 glCreateVertexArrays(1, &prewarp_vao);
513 glBindVertexArray(prewarp_vao);
514 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
516 GLint position_attrib = glGetAttribLocation(prewarp_program, "position");
517 glEnableVertexArrayAttrib(prewarp_vao, position_attrib);
518 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
520 uniform_image0_tex = glGetUniformLocation(prewarp_program, "image0_tex");
521 uniform_image1_tex = glGetUniformLocation(prewarp_program, "image1_tex");
522 uniform_flow_tex = glGetUniformLocation(prewarp_program, "flow_tex");
524 uniform_image_size = glGetUniformLocation(prewarp_program, "image_size");
527 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)
529 glUseProgram(prewarp_program);
531 bind_sampler(prewarp_program, uniform_image0_tex, 0, tex0_view, nearest_sampler);
532 bind_sampler(prewarp_program, uniform_image1_tex, 1, tex1_view, linear_sampler);
533 bind_sampler(prewarp_program, uniform_flow_tex, 2, flow_tex, nearest_sampler);
535 glProgramUniform2f(prewarp_program, uniform_image_size, level_width, level_height);
537 glViewport(0, 0, level_width, level_height);
539 glBindVertexArray(prewarp_vao);
540 fbos.render_to(I_tex, I_t_tex, normalized_flow_tex);
541 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
544 // From I, calculate the partial derivatives I_x and I_y. We use a four-tap
545 // central difference filter, since apparently, that's tradition (I haven't
546 // measured quality versus a more normal 0.5 (I[x+1] - I[x-1]).)
547 // The coefficients come from
549 // https://en.wikipedia.org/wiki/Finite_difference_coefficient
551 // Also computes β_0, since it depends only on I_x and I_y.
555 void exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, int level_width, int level_height);
558 PersistentFBOSet<2> fbos;
560 GLuint derivatives_vs_obj;
561 GLuint derivatives_fs_obj;
562 GLuint derivatives_program;
563 GLuint derivatives_vao;
568 Derivatives::Derivatives()
570 derivatives_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
571 derivatives_fs_obj = compile_shader(read_file("derivatives.frag"), GL_FRAGMENT_SHADER);
572 derivatives_program = link_program(derivatives_vs_obj, derivatives_fs_obj);
574 // Set up the VAO containing all the required position/texcoord data.
575 glCreateVertexArrays(1, &derivatives_vao);
576 glBindVertexArray(derivatives_vao);
577 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
579 GLint position_attrib = glGetAttribLocation(derivatives_program, "position");
580 glEnableVertexArrayAttrib(derivatives_vao, position_attrib);
581 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
583 uniform_tex = glGetUniformLocation(derivatives_program, "tex");
586 void Derivatives::exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, int level_width, int level_height)
588 glUseProgram(derivatives_program);
590 bind_sampler(derivatives_program, uniform_tex, 0, input_tex, nearest_sampler);
592 glViewport(0, 0, level_width, level_height);
594 glBindVertexArray(derivatives_vao);
595 fbos.render_to(I_x_y_tex, beta_0_tex);
596 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
599 // Calculate the smoothness constraints between neighboring pixels;
600 // s_x(x,y) stores smoothness between pixel (x,y) and (x+1,y),
601 // and s_y(x,y) stores between (x,y) and (x,y+1). We'll sample with
602 // border color (0,0) later, so that there's zero diffusion out of
605 // See variational_refinement.txt for more information.
606 class ComputeSmoothness {
609 void exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height);
612 PersistentFBOSet<2> fbos;
614 GLuint smoothness_vs_obj;
615 GLuint smoothness_fs_obj;
616 GLuint smoothness_program;
617 GLuint smoothness_vao;
619 GLuint uniform_flow_tex, uniform_diff_flow_tex;
620 GLuint uniform_alpha;
623 ComputeSmoothness::ComputeSmoothness()
625 smoothness_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
626 smoothness_fs_obj = compile_shader(read_file("smoothness.frag"), GL_FRAGMENT_SHADER);
627 smoothness_program = link_program(smoothness_vs_obj, smoothness_fs_obj);
629 // Set up the VAO containing all the required position/texcoord data.
630 glCreateVertexArrays(1, &smoothness_vao);
631 glBindVertexArray(smoothness_vao);
632 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
634 GLint position_attrib = glGetAttribLocation(smoothness_program, "position");
635 glEnableVertexArrayAttrib(smoothness_vao, position_attrib);
636 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
638 uniform_flow_tex = glGetUniformLocation(smoothness_program, "flow_tex");
639 uniform_diff_flow_tex = glGetUniformLocation(smoothness_program, "diff_flow_tex");
640 uniform_alpha = glGetUniformLocation(smoothness_program, "alpha");
643 void ComputeSmoothness::exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height)
645 glUseProgram(smoothness_program);
647 bind_sampler(smoothness_program, uniform_flow_tex, 0, flow_tex, nearest_sampler);
648 bind_sampler(smoothness_program, uniform_diff_flow_tex, 1, diff_flow_tex, nearest_sampler);
649 glProgramUniform1f(smoothness_program, uniform_alpha, vr_alpha);
651 glViewport(0, 0, level_width, level_height);
654 glBindVertexArray(smoothness_vao);
655 fbos.render_to(smoothness_x_tex, smoothness_y_tex);
656 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
658 // Make sure the smoothness on the right and upper borders is zero.
659 // We could have done this by making (W-1)xH and Wx(H-1) textures instead
660 // (we're sampling smoothness with all-zero border color), but we'd
661 // have to adjust the sampling coordinates, which is annoying.
662 glClearTexSubImage(smoothness_x_tex, 0, level_width - 1, 0, 0, 1, level_height, 1, GL_RED, GL_FLOAT, nullptr);
663 glClearTexSubImage(smoothness_y_tex, 0, 0, level_height - 1, 0, level_width, 1, 1, GL_RED, GL_FLOAT, nullptr);
666 // Set up the equations set (two equations in two unknowns, per pixel).
667 // We store five floats; the three non-redundant elements of the 2x2 matrix (A)
668 // as 32-bit floats, and the two elements on the right-hand side (b) as 16-bit
669 // floats. (Actually, we store the inverse of the diagonal elements, because
670 // we only ever need to divide by them.) This fits into four u32 values;
671 // R, G, B for the matrix (the last element is symmetric) and A for the two b values.
672 // All the values of the energy term (E_I, E_G, E_S), except the smoothness
673 // terms that depend on other pixels, are calculated in one pass.
675 // See variational_refinement.txt for more information.
676 class SetupEquations {
679 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);
682 PersistentFBOSet<1> fbos;
684 GLuint equations_vs_obj;
685 GLuint equations_fs_obj;
686 GLuint equations_program;
687 GLuint equations_vao;
689 GLuint uniform_I_x_y_tex, uniform_I_t_tex;
690 GLuint uniform_diff_flow_tex, uniform_base_flow_tex;
691 GLuint uniform_beta_0_tex;
692 GLuint uniform_smoothness_x_tex, uniform_smoothness_y_tex;
693 GLuint uniform_gamma, uniform_delta;
696 SetupEquations::SetupEquations()
698 equations_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
699 equations_fs_obj = compile_shader(read_file("equations.frag"), GL_FRAGMENT_SHADER);
700 equations_program = link_program(equations_vs_obj, equations_fs_obj);
702 // Set up the VAO containing all the required position/texcoord data.
703 glCreateVertexArrays(1, &equations_vao);
704 glBindVertexArray(equations_vao);
705 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
707 GLint position_attrib = glGetAttribLocation(equations_program, "position");
708 glEnableVertexArrayAttrib(equations_vao, position_attrib);
709 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
711 uniform_I_x_y_tex = glGetUniformLocation(equations_program, "I_x_y_tex");
712 uniform_I_t_tex = glGetUniformLocation(equations_program, "I_t_tex");
713 uniform_diff_flow_tex = glGetUniformLocation(equations_program, "diff_flow_tex");
714 uniform_base_flow_tex = glGetUniformLocation(equations_program, "base_flow_tex");
715 uniform_beta_0_tex = glGetUniformLocation(equations_program, "beta_0_tex");
716 uniform_smoothness_x_tex = glGetUniformLocation(equations_program, "smoothness_x_tex");
717 uniform_smoothness_y_tex = glGetUniformLocation(equations_program, "smoothness_y_tex");
718 uniform_gamma = glGetUniformLocation(equations_program, "gamma");
719 uniform_delta = glGetUniformLocation(equations_program, "delta");
722 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)
724 glUseProgram(equations_program);
726 bind_sampler(equations_program, uniform_I_x_y_tex, 0, I_x_y_tex, nearest_sampler);
727 bind_sampler(equations_program, uniform_I_t_tex, 1, I_t_tex, nearest_sampler);
728 bind_sampler(equations_program, uniform_diff_flow_tex, 2, diff_flow_tex, nearest_sampler);
729 bind_sampler(equations_program, uniform_base_flow_tex, 3, base_flow_tex, nearest_sampler);
730 bind_sampler(equations_program, uniform_beta_0_tex, 4, beta_0_tex, nearest_sampler);
731 bind_sampler(equations_program, uniform_smoothness_x_tex, 5, smoothness_x_tex, smoothness_sampler);
732 bind_sampler(equations_program, uniform_smoothness_y_tex, 6, smoothness_y_tex, smoothness_sampler);
733 glProgramUniform1f(equations_program, uniform_delta, vr_delta);
734 glProgramUniform1f(equations_program, uniform_gamma, vr_gamma);
736 glViewport(0, 0, level_width, level_height);
738 glBindVertexArray(equations_vao);
739 fbos.render_to(equation_tex);
740 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
743 // Actually solve the equation sets made by SetupEquations, by means of
744 // successive over-relaxation (SOR).
746 // See variational_refinement.txt for more information.
750 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);
753 PersistentFBOSet<1> fbos;
760 GLuint uniform_diff_flow_tex;
761 GLuint uniform_equation_tex;
762 GLuint uniform_smoothness_x_tex, uniform_smoothness_y_tex;
767 sor_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
768 sor_fs_obj = compile_shader(read_file("sor.frag"), GL_FRAGMENT_SHADER);
769 sor_program = link_program(sor_vs_obj, sor_fs_obj);
771 // Set up the VAO containing all the required position/texcoord data.
772 glCreateVertexArrays(1, &sor_vao);
773 glBindVertexArray(sor_vao);
774 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
776 GLint position_attrib = glGetAttribLocation(sor_program, "position");
777 glEnableVertexArrayAttrib(sor_vao, position_attrib);
778 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
780 uniform_diff_flow_tex = glGetUniformLocation(sor_program, "diff_flow_tex");
781 uniform_equation_tex = glGetUniformLocation(sor_program, "equation_tex");
782 uniform_smoothness_x_tex = glGetUniformLocation(sor_program, "smoothness_x_tex");
783 uniform_smoothness_y_tex = glGetUniformLocation(sor_program, "smoothness_y_tex");
786 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)
788 glUseProgram(sor_program);
790 bind_sampler(sor_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler);
791 bind_sampler(sor_program, uniform_smoothness_x_tex, 1, smoothness_x_tex, smoothness_sampler);
792 bind_sampler(sor_program, uniform_smoothness_y_tex, 2, smoothness_y_tex, smoothness_sampler);
793 bind_sampler(sor_program, uniform_equation_tex, 3, equation_tex, nearest_sampler);
795 glViewport(0, 0, level_width, level_height);
797 glBindVertexArray(sor_vao);
798 fbos.render_to(diff_flow_tex); // NOTE: Bind to same as we render from!
800 for (int i = 0; i < num_iterations; ++i) {
801 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
802 if (i != num_iterations - 1) {
808 // Simply add the differential flow found by the variational refinement to the base flow.
809 // The output is in base_flow_tex; we don't need to make a new texture.
813 void exec(GLuint base_flow_tex, GLuint diff_flow_tex, int level_width, int level_height);
816 PersistentFBOSet<1> fbos;
818 GLuint add_flow_vs_obj;
819 GLuint add_flow_fs_obj;
820 GLuint add_flow_program;
823 GLuint uniform_diff_flow_tex;
826 AddBaseFlow::AddBaseFlow()
828 add_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
829 add_flow_fs_obj = compile_shader(read_file("add_base_flow.frag"), GL_FRAGMENT_SHADER);
830 add_flow_program = link_program(add_flow_vs_obj, add_flow_fs_obj);
832 // Set up the VAO containing all the required position/texcoord data.
833 glCreateVertexArrays(1, &add_flow_vao);
834 glBindVertexArray(add_flow_vao);
835 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
837 GLint position_attrib = glGetAttribLocation(add_flow_program, "position");
838 glEnableVertexArrayAttrib(add_flow_vao, position_attrib);
839 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
841 uniform_diff_flow_tex = glGetUniformLocation(add_flow_program, "diff_flow_tex");
844 void AddBaseFlow::exec(GLuint base_flow_tex, GLuint diff_flow_tex, int level_width, int level_height)
846 glUseProgram(add_flow_program);
848 bind_sampler(add_flow_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler);
850 glViewport(0, 0, level_width, level_height);
852 glBlendFunc(GL_ONE, GL_ONE);
853 glBindVertexArray(add_flow_vao);
854 fbos.render_to(base_flow_tex);
856 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
859 // Take a copy of the flow, bilinearly interpolated and scaled up.
863 void exec(GLuint in_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height);
866 PersistentFBOSet<1> fbos;
868 GLuint resize_flow_vs_obj;
869 GLuint resize_flow_fs_obj;
870 GLuint resize_flow_program;
871 GLuint resize_flow_vao;
873 GLuint uniform_flow_tex;
874 GLuint uniform_scale_factor;
877 ResizeFlow::ResizeFlow()
879 resize_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
880 resize_flow_fs_obj = compile_shader(read_file("resize_flow.frag"), GL_FRAGMENT_SHADER);
881 resize_flow_program = link_program(resize_flow_vs_obj, resize_flow_fs_obj);
883 // Set up the VAO containing all the required position/texcoord data.
884 glCreateVertexArrays(1, &resize_flow_vao);
885 glBindVertexArray(resize_flow_vao);
886 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
888 GLint position_attrib = glGetAttribLocation(resize_flow_program, "position");
889 glEnableVertexArrayAttrib(resize_flow_vao, position_attrib);
890 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
892 uniform_flow_tex = glGetUniformLocation(resize_flow_program, "flow_tex");
893 uniform_scale_factor = glGetUniformLocation(resize_flow_program, "scale_factor");
896 void ResizeFlow::exec(GLuint flow_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height)
898 glUseProgram(resize_flow_program);
900 bind_sampler(resize_flow_program, uniform_flow_tex, 0, flow_tex, nearest_sampler);
902 glProgramUniform2f(resize_flow_program, uniform_scale_factor, float(output_width) / input_width, float(output_height) / input_height);
904 glViewport(0, 0, output_width, output_height);
906 glBindVertexArray(resize_flow_vao);
907 fbos.render_to(out_tex);
909 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
915 pair<GLuint, GLuint> begin_timer(const string &name, int level);
921 pair<GLuint, GLuint> query;
923 vector<Timer> timers;
926 pair<GLuint, GLuint> GPUTimers::begin_timer(const string &name, int level)
928 if (!enable_timing) {
929 return make_pair(0, 0);
933 glGenQueries(2, queries);
934 glQueryCounter(queries[0], GL_TIMESTAMP);
939 timer.query.first = queries[0];
940 timer.query.second = queries[1];
941 timers.push_back(timer);
945 void GPUTimers::print()
947 for (const Timer &timer : timers) {
948 // NOTE: This makes the CPU wait for the GPU.
949 GLuint64 time_start, time_end;
950 glGetQueryObjectui64v(timer.query.first, GL_QUERY_RESULT, &time_start);
951 glGetQueryObjectui64v(timer.query.second, GL_QUERY_RESULT, &time_end);
952 //fprintf(stderr, "GPU time used = %.1f ms\n", time_elapsed / 1e6);
953 for (int i = 0; i < timer.level * 2; ++i) {
954 fprintf(stderr, " ");
956 fprintf(stderr, "%-30s %4.1f ms\n", timer.name.c_str(), GLint64(time_end - time_start) / 1e6);
960 // A simple RAII class for timing until the end of the scope.
963 ScopedTimer(const string &name, GPUTimers *timers)
964 : timers(timers), level(0)
966 query = timers->begin_timer(name, level);
969 ScopedTimer(const string &name, ScopedTimer *parent_timer)
970 : timers(parent_timer->timers),
971 level(parent_timer->level + 1)
973 query = timers->begin_timer(name, level);
983 if (enable_timing && !ended) {
984 glQueryCounter(query.second, GL_TIMESTAMP);
992 pair<GLuint, GLuint> query;
996 class DISComputeFlow {
998 DISComputeFlow(int width, int height);
1000 // Returns a texture that must be released with release_texture()
1002 GLuint exec(GLuint tex0, GLuint tex1);
1003 void release_texture(GLuint tex);
1007 GLuint initial_flow_tex;
1009 // The various passes.
1011 MotionSearch motion_search;
1014 Derivatives derivatives;
1015 ComputeSmoothness compute_smoothness;
1016 SetupEquations setup_equations;
1018 AddBaseFlow add_base_flow;
1019 ResizeFlow resize_flow;
1024 GLuint width, height;
1025 bool in_use = false;
1027 vector<Texture> textures;
1029 GLuint get_texture(GLenum format, GLuint width, GLuint height);
1032 DISComputeFlow::DISComputeFlow(int width, int height)
1033 : width(width), height(height)
1035 // Make some samplers.
1036 glCreateSamplers(1, &nearest_sampler);
1037 glSamplerParameteri(nearest_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
1038 glSamplerParameteri(nearest_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
1039 glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
1040 glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
1042 glCreateSamplers(1, &linear_sampler);
1043 glSamplerParameteri(linear_sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
1044 glSamplerParameteri(linear_sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
1045 glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
1046 glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
1048 // The smoothness is sampled so that once we get to a smoothness involving
1049 // a value outside the border, the diffusivity between the two becomes zero.
1050 glCreateSamplers(1, &smoothness_sampler);
1051 glSamplerParameteri(smoothness_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
1052 glSamplerParameteri(smoothness_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
1053 glSamplerParameteri(smoothness_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
1054 glSamplerParameteri(smoothness_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
1055 float zero[] = { 0.0f, 0.0f, 0.0f, 0.0f };
1056 glSamplerParameterfv(smoothness_sampler, GL_TEXTURE_BORDER_COLOR, zero);
1058 // Initial flow is zero, 1x1.
1059 glCreateTextures(GL_TEXTURE_2D, 1, &initial_flow_tex);
1060 glTextureStorage2D(initial_flow_tex, 1, GL_RG16F, 1, 1);
1061 glClearTexImage(initial_flow_tex, 0, GL_RG, GL_FLOAT, nullptr);
1064 GLuint DISComputeFlow::exec(GLuint tex0, GLuint tex1)
1066 for (const Texture &tex : textures) {
1067 assert(!tex.in_use);
1070 int prev_level_width = 1, prev_level_height = 1;
1071 GLuint prev_level_flow_tex = initial_flow_tex;
1075 ScopedTimer total_timer("Total", &timers);
1076 for (int level = coarsest_level; level >= int(finest_level); --level) {
1077 char timer_name[256];
1078 snprintf(timer_name, sizeof(timer_name), "Level %d", level);
1079 ScopedTimer level_timer(timer_name, &total_timer);
1081 int level_width = width >> level;
1082 int level_height = height >> level;
1083 float patch_spacing_pixels = patch_size_pixels * (1.0f - patch_overlap_ratio);
1084 int width_patches = 1 + lrintf((level_width - patch_size_pixels) / patch_spacing_pixels);
1085 int height_patches = 1 + lrintf((level_height - patch_size_pixels) / patch_spacing_pixels);
1087 // Make sure we always read from the correct level; the chosen
1088 // mipmapping could otherwise be rather unpredictable, especially
1089 // during motion search.
1090 // TODO: create these beforehand, and stop leaking them.
1091 GLuint tex0_view, tex1_view;
1092 glGenTextures(1, &tex0_view);
1093 glTextureView(tex0_view, GL_TEXTURE_2D, tex0, GL_R8, level, 1, 0, 1);
1094 glGenTextures(1, &tex1_view);
1095 glTextureView(tex1_view, GL_TEXTURE_2D, tex1, GL_R8, level, 1, 0, 1);
1097 // Create a new texture; we could be fancy and render use a multi-level
1098 // texture, but meh.
1099 GLuint grad0_tex = get_texture(GL_RG16F, level_width, level_height);
1101 // Find the derivative.
1103 ScopedTimer timer("Sobel", &level_timer);
1104 sobel.exec(tex0_view, grad0_tex, level_width, level_height);
1107 // Motion search to find the initial flow. We use the flow from the previous
1108 // level (sampled bilinearly; no fancy tricks) as a guide, then search from there.
1110 // Create an output flow texture.
1111 GLuint flow_out_tex = get_texture(GL_RGB16F, width_patches, height_patches);
1115 ScopedTimer timer("Motion search", &level_timer);
1116 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);
1118 release_texture(grad0_tex);
1122 // Set up an output texture (initially zero).
1123 GLuint dense_flow_tex = get_texture(GL_RGB16F, level_width, level_height);
1124 glClearTexImage(dense_flow_tex, 0, GL_RGB, GL_FLOAT, nullptr);
1128 ScopedTimer timer("Densification", &level_timer);
1129 densify.exec(tex0_view, tex1_view, flow_out_tex, dense_flow_tex, level_width, level_height, width_patches, height_patches);
1131 release_texture(flow_out_tex);
1133 // Everything below here in the loop belongs to variational refinement.
1134 ScopedTimer varref_timer("Variational refinement", &level_timer);
1136 // Prewarping; create I and I_t, and a normalized base flow (so we don't
1137 // have to normalize it over and over again, and also save some bandwidth).
1139 // During the entire rest of the variational refinement, flow will be measured
1140 // in pixels, not 0..1 normalized OpenGL texture coordinates.
1141 // This is because variational refinement depends so heavily on derivatives,
1142 // which are measured in intensity levels per pixel.
1143 GLuint I_tex = get_texture(GL_R16F, level_width, level_height);
1144 GLuint I_t_tex = get_texture(GL_R16F, level_width, level_height);
1145 GLuint base_flow_tex = get_texture(GL_RG16F, level_width, level_height);
1147 ScopedTimer timer("Prewarping", &varref_timer);
1148 prewarp.exec(tex0_view, tex1_view, dense_flow_tex, I_tex, I_t_tex, base_flow_tex, level_width, level_height);
1150 release_texture(dense_flow_tex);
1152 // Calculate I_x and I_y. We're only calculating first derivatives;
1153 // the others will be taken on-the-fly in order to sample from fewer
1154 // textures overall, since sampling from the L1 cache is cheap.
1155 // (TODO: Verify that this is indeed faster than making separate
1156 // double-derivative textures.)
1157 GLuint I_x_y_tex = get_texture(GL_RG16F, level_width, level_height);
1158 GLuint beta_0_tex = get_texture(GL_R16F, level_width, level_height);
1160 ScopedTimer timer("First derivatives", &varref_timer);
1161 derivatives.exec(I_tex, I_x_y_tex, beta_0_tex, level_width, level_height);
1163 release_texture(I_tex);
1165 // We need somewhere to store du and dv (the flow increment, relative
1166 // to the non-refined base flow u0 and v0). It starts at zero.
1167 GLuint du_dv_tex = get_texture(GL_RG16F, level_width, level_height);
1168 glClearTexImage(du_dv_tex, 0, GL_RG, GL_FLOAT, nullptr);
1170 // And for smoothness.
1171 GLuint smoothness_x_tex = get_texture(GL_R16F, level_width, level_height);
1172 GLuint smoothness_y_tex = get_texture(GL_R16F, level_width, level_height);
1174 // And finally for the equation set. See SetupEquations for
1175 // the storage format.
1176 GLuint equation_tex = get_texture(GL_RGBA32UI, level_width, level_height);
1178 for (int outer_idx = 0; outer_idx < level + 1; ++outer_idx) {
1179 // Calculate the smoothness terms between the neighboring pixels,
1180 // both in x and y direction.
1182 ScopedTimer timer("Compute smoothness", &varref_timer);
1183 compute_smoothness.exec(base_flow_tex, du_dv_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height);
1186 // Set up the 2x2 equation system for each pixel.
1188 ScopedTimer timer("Set up equations", &varref_timer);
1189 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);
1192 // Run a few SOR (or quasi-SOR, since we're not really Jacobi) iterations.
1193 // Note that these are to/from the same texture.
1195 ScopedTimer timer("SOR", &varref_timer);
1196 sor.exec(du_dv_tex, equation_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height, 5);
1200 release_texture(I_t_tex);
1201 release_texture(I_x_y_tex);
1202 release_texture(beta_0_tex);
1203 release_texture(smoothness_x_tex);
1204 release_texture(smoothness_y_tex);
1205 release_texture(equation_tex);
1207 // Add the differential flow found by the variational refinement to the base flow,
1208 // giving the final flow estimate for this level.
1209 // The output is in diff_flow_tex; we don't need to make a new texture.
1210 // You can comment out this part if you wish to test disabling of the variational refinement.
1212 ScopedTimer timer("Add differential flow", &varref_timer);
1213 add_base_flow.exec(base_flow_tex, du_dv_tex, level_width, level_height);
1215 release_texture(du_dv_tex);
1217 if (prev_level_flow_tex != initial_flow_tex) {
1218 release_texture(prev_level_flow_tex);
1220 prev_level_flow_tex = base_flow_tex;
1221 prev_level_width = level_width;
1222 prev_level_height = level_height;
1228 // Scale up the flow to the final size (if needed).
1229 if (finest_level == 0) {
1230 return prev_level_flow_tex;
1232 GLuint final_tex = get_texture(GL_RG16F, width, height);
1233 resize_flow.exec(prev_level_flow_tex, final_tex, prev_level_width, prev_level_height, width, height);
1234 release_texture(prev_level_flow_tex);
1239 GLuint DISComputeFlow::get_texture(GLenum format, GLuint width, GLuint height)
1241 for (Texture &tex : textures) {
1242 if (!tex.in_use && tex.format == format &&
1243 tex.width == width && tex.height == height) {
1250 glCreateTextures(GL_TEXTURE_2D, 1, &tex.tex_num);
1251 glTextureStorage2D(tex.tex_num, 1, format, width, height);
1252 tex.format = format;
1254 tex.height = height;
1256 textures.push_back(tex);
1260 void DISComputeFlow::release_texture(GLuint tex_num)
1262 for (Texture &tex : textures) {
1263 if (tex.tex_num == tex_num) {
1272 void write_flow(const char *filename, const float *dense_flow, unsigned width, unsigned height)
1274 FILE *flowfp = fopen(filename, "wb");
1275 fprintf(flowfp, "FEIH");
1276 fwrite(&width, 4, 1, flowfp);
1277 fwrite(&height, 4, 1, flowfp);
1278 for (unsigned y = 0; y < height; ++y) {
1279 int yy = height - y - 1;
1280 for (unsigned x = 0; x < unsigned(width); ++x) {
1281 float du = dense_flow[(yy * width + x) * 2 + 0];
1282 float dv = dense_flow[(yy * width + x) * 2 + 1];
1286 fwrite(&du, 4, 1, flowfp);
1287 fwrite(&dv, 4, 1, flowfp);
1293 void write_ppm(const char *filename, const float *dense_flow, unsigned width, unsigned height)
1295 FILE *fp = fopen(filename, "wb");
1296 fprintf(fp, "P6\n%d %d\n255\n", width, height);
1297 for (unsigned y = 0; y < unsigned(height); ++y) {
1298 int yy = height - y - 1;
1299 for (unsigned x = 0; x < unsigned(width); ++x) {
1300 float du = dense_flow[(yy * width + x) * 2 + 0];
1301 float dv = dense_flow[(yy * width + x) * 2 + 1];
1306 flow2rgb(du, dv, &r, &g, &b);
1315 int main(int argc, char **argv)
1317 static const option long_options[] = {
1318 { "alpha", required_argument, 0, 'a' },
1319 { "delta", required_argument, 0, 'd' },
1320 { "gamma", required_argument, 0, 'g' },
1321 { "disable-timing", no_argument, 0, 1000 }
1325 int option_index = 0;
1326 int c = getopt_long(argc, argv, "a:d:g:", long_options, &option_index);
1333 vr_alpha = atof(optarg);
1336 vr_delta = atof(optarg);
1339 vr_gamma = atof(optarg);
1342 enable_timing = false;
1345 fprintf(stderr, "Unknown option '%s'\n", argv[option_index]);
1350 if (SDL_Init(SDL_INIT_EVERYTHING) == -1) {
1351 fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError());
1354 SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
1355 SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0);
1356 SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0);
1357 SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
1359 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
1360 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
1361 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 5);
1362 // SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
1363 SDL_Window *window = SDL_CreateWindow("OpenGL window",
1364 SDL_WINDOWPOS_UNDEFINED,
1365 SDL_WINDOWPOS_UNDEFINED,
1368 SDL_GLContext context = SDL_GL_CreateContext(window);
1369 assert(context != nullptr);
1371 const char *filename0 = argc >= (optind + 1) ? argv[optind] : "test1499.png";
1372 const char *filename1 = argc >= (optind + 2) ? argv[optind + 1] : "test1500.png";
1373 const char *flow_filename = argc >= (optind + 3) ? argv[optind + 2] : "flow.flo";
1374 fprintf(stderr, "%s %s -> %s\n", filename0, filename1, flow_filename);
1377 unsigned width1, height1, width2, height2;
1378 GLuint tex0 = load_texture(filename0, &width1, &height1);
1379 GLuint tex1 = load_texture(filename1, &width2, &height2);
1381 if (width1 != width2 || height1 != height2) {
1382 fprintf(stderr, "Image dimensions don't match (%dx%d versus %dx%d)\n",
1383 width1, height1, width2, height2);
1387 // FIXME: Should be part of DISComputeFlow (but needs to be initialized
1388 // before all the render passes).
1389 float vertices[] = {
1395 glCreateBuffers(1, &vertex_vbo);
1396 glNamedBufferData(vertex_vbo, sizeof(vertices), vertices, GL_STATIC_DRAW);
1397 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
1399 DISComputeFlow compute_flow(width1, height1);
1400 GLuint final_tex = compute_flow.exec(tex0, tex1);
1402 unique_ptr<float[]> dense_flow(new float[width1 * height1 * 2]);
1403 glGetTextureImage(final_tex, 0, GL_RG, GL_FLOAT, width1 * height1 * 2 * sizeof(float), dense_flow.get());
1405 compute_flow.release_texture(final_tex);
1407 write_flow(flow_filename, dense_flow.get(), width1, height1);
1408 write_ppm("flow.ppm", dense_flow.get(), width1, height1);
1412 // See if there are more flows on the command line (ie., more than three arguments),
1413 // and if so, process them.
1414 int num_flows = (argc - optind) / 3;
1415 for (int i = 1; i < num_flows; ++i) {
1416 const char *filename0 = argv[optind + i * 3 + 0];
1417 const char *filename1 = argv[optind + i * 3 + 1];
1418 const char *flow_filename = argv[optind + i * 3 + 2];
1419 fprintf(stderr, "%s %s -> %s\n", filename0, filename1, flow_filename);
1421 GLuint width, height;
1422 GLuint tex0 = load_texture(filename0, &width, &height);
1423 if (width != width1 || height != height1) {
1424 fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n",
1425 filename0, width, height, width1, height1);
1429 GLuint tex1 = load_texture(filename1, &width, &height);
1430 if (width != width1 || height != height1) {
1431 fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n",
1432 filename1, width, height, width1, height1);
1436 GLuint final_tex = compute_flow.exec(tex0, tex1);
1438 unique_ptr<float[]> dense_flow(new float[width * height * 2]);
1439 glGetTextureImage(final_tex, 0, GL_RG, GL_FLOAT, width * height * 2 * sizeof(float), dense_flow.get());
1441 compute_flow.release_texture(final_tex);
1443 write_flow(flow_filename, dense_flow.get(), width, height);
1446 fprintf(stderr, "err = %d\n", glGetError());