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 // Some global OpenGL objects.
41 // TODO: These should really be part of DISComputeFlow.
42 GLuint nearest_sampler, linear_sampler, smoothness_sampler;
45 string read_file(const string &filename)
47 FILE *fp = fopen(filename.c_str(), "r");
49 perror(filename.c_str());
53 int ret = fseek(fp, 0, SEEK_END);
55 perror("fseek(SEEK_END)");
61 ret = fseek(fp, 0, SEEK_SET);
63 perror("fseek(SEEK_SET)");
69 ret = fread(&str[0], size, 1, fp);
75 fprintf(stderr, "Short read when trying to read %d bytes from %s\n",
76 size, filename.c_str());
85 GLuint compile_shader(const string &shader_src, GLenum type)
87 GLuint obj = glCreateShader(type);
88 const GLchar* source[] = { shader_src.data() };
89 const GLint length[] = { (GLint)shader_src.size() };
90 glShaderSource(obj, 1, source, length);
93 GLchar info_log[4096];
94 GLsizei log_length = sizeof(info_log) - 1;
95 glGetShaderInfoLog(obj, log_length, &log_length, info_log);
96 info_log[log_length] = 0;
97 if (strlen(info_log) > 0) {
98 fprintf(stderr, "Shader compile log: %s\n", info_log);
102 glGetShaderiv(obj, GL_COMPILE_STATUS, &status);
103 if (status == GL_FALSE) {
104 // Add some line numbers to easier identify compile errors.
105 string src_with_lines = "/* 1 */ ";
107 for (char ch : shader_src) {
108 src_with_lines.push_back(ch);
111 snprintf(buf, sizeof(buf), "/* %3zu */ ", ++lineno);
112 src_with_lines += buf;
116 fprintf(stderr, "Failed to compile shader:\n%s\n", src_with_lines.c_str());
123 GLuint load_texture(const char *filename, unsigned *width_ret, unsigned *height_ret)
125 SDL_Surface *surf = IMG_Load(filename);
126 if (surf == nullptr) {
127 fprintf(stderr, "IMG_Load(%s): %s\n", filename, IMG_GetError());
131 // For whatever reason, SDL doesn't support converting to YUV surfaces
132 // nor grayscale, so we'll do it (slowly) ourselves.
133 SDL_Surface *rgb_surf = SDL_ConvertSurfaceFormat(surf, SDL_PIXELFORMAT_RGBA8888, /*flags=*/0);
134 if (rgb_surf == nullptr) {
135 fprintf(stderr, "SDL_ConvertSurfaceFormat(%s): %s\n", filename, SDL_GetError());
139 SDL_FreeSurface(surf);
141 unsigned width = rgb_surf->w, height = rgb_surf->h;
142 const uint8_t *sptr = (uint8_t *)rgb_surf->pixels;
143 unique_ptr<uint8_t[]> pix(new uint8_t[width * height]);
145 // Extract the Y component, and convert to bottom-left origin.
146 for (unsigned y = 0; y < height; ++y) {
147 unsigned y2 = height - 1 - y;
148 for (unsigned x = 0; x < width; ++x) {
149 uint8_t r = sptr[(y2 * width + x) * 4 + 3];
150 uint8_t g = sptr[(y2 * width + x) * 4 + 2];
151 uint8_t b = sptr[(y2 * width + x) * 4 + 1];
154 pix[y * width + x] = lrintf(r * 0.2126f + g * 0.7152f + b * 0.0722f);
157 SDL_FreeSurface(rgb_surf);
160 for (int w = width, h = height; w > 1 || h > 1; ) {
167 glCreateTextures(GL_TEXTURE_2D, 1, &tex);
168 glTextureStorage2D(tex, levels, GL_R8, width, height);
169 glTextureSubImage2D(tex, 0, 0, 0, width, height, GL_RED, GL_UNSIGNED_BYTE, pix.get());
170 glGenerateTextureMipmap(tex);
173 *height_ret = height;
178 GLuint link_program(GLuint vs_obj, GLuint fs_obj)
180 GLuint program = glCreateProgram();
181 glAttachShader(program, vs_obj);
182 glAttachShader(program, fs_obj);
183 glLinkProgram(program);
185 glGetProgramiv(program, GL_LINK_STATUS, &success);
186 if (success == GL_FALSE) {
187 GLchar error_log[1024] = {0};
188 glGetProgramInfoLog(program, 1024, nullptr, error_log);
189 fprintf(stderr, "Error linking program: %s\n", error_log);
195 GLuint generate_vbo(GLint size, GLsizeiptr data_size, const GLvoid *data)
198 glCreateBuffers(1, &vbo);
199 glBufferData(GL_ARRAY_BUFFER, data_size, data, GL_STATIC_DRAW);
200 glNamedBufferData(vbo, data_size, data, GL_STATIC_DRAW);
204 GLuint fill_vertex_attribute(GLuint vao, GLuint glsl_program_num, const string &attribute_name, GLint size, GLenum type, GLsizeiptr data_size, const GLvoid *data)
206 int attrib = glGetAttribLocation(glsl_program_num, attribute_name.c_str());
211 GLuint vbo = generate_vbo(size, data_size, data);
213 glBindBuffer(GL_ARRAY_BUFFER, vbo);
214 glEnableVertexArrayAttrib(vao, attrib);
215 glVertexAttribPointer(attrib, size, type, GL_FALSE, 0, BUFFER_OFFSET(0));
216 glBindBuffer(GL_ARRAY_BUFFER, 0);
221 void bind_sampler(GLuint program, GLint location, GLuint texture_unit, GLuint tex, GLuint sampler)
223 if (location == -1) {
227 glBindTextureUnit(texture_unit, tex);
228 glBindSampler(texture_unit, sampler);
229 glProgramUniform1i(program, location, texture_unit);
232 // A class that caches FBOs that render to a given set of textures.
233 // It never frees anything, so it is only suitable for rendering to
234 // the same (small) set of textures over and over again.
235 template<size_t num_elements>
236 class PersistentFBOSet {
238 void render_to(const array<GLuint, num_elements> &textures);
240 // Convenience wrappers.
241 void render_to(GLuint texture0, enable_if<num_elements == 1> * = nullptr) {
242 render_to({{texture0}});
245 void render_to(GLuint texture0, GLuint texture1, enable_if<num_elements == 2> * = nullptr) {
246 render_to({{texture0, texture1}});
249 void render_to(GLuint texture0, GLuint texture1, GLuint texture2, enable_if<num_elements == 3> * = nullptr) {
250 render_to({{texture0, texture1, texture2}});
253 void render_to(GLuint texture0, GLuint texture1, GLuint texture2, GLuint texture3, enable_if<num_elements == 4> * = nullptr) {
254 render_to({{texture0, texture1, texture2, texture3}});
258 // TODO: Delete these on destruction.
259 map<array<GLuint, num_elements>, GLuint> fbos;
262 template<size_t num_elements>
263 void PersistentFBOSet<num_elements>::render_to(const array<GLuint, num_elements> &textures)
265 auto it = fbos.find(textures);
266 if (it != fbos.end()) {
267 glBindFramebuffer(GL_FRAMEBUFFER, it->second);
272 glCreateFramebuffers(1, &fbo);
273 GLenum bufs[num_elements];
274 for (size_t i = 0; i < num_elements; ++i) {
275 glNamedFramebufferTexture(fbo, GL_COLOR_ATTACHMENT0 + i, textures[i], 0);
276 bufs[i] = GL_COLOR_ATTACHMENT0 + i;
278 glNamedFramebufferDrawBuffers(fbo, num_elements, bufs);
280 fbos[textures] = fbo;
281 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
284 // Compute gradients in every point, used for the motion search.
285 // The DIS paper doesn't actually mention how these are computed,
286 // but seemingly, a 3x3 Sobel operator is used here (at least in
287 // later versions of the code), while a [1 -8 0 8 -1] kernel is
288 // used for all the derivatives in the variational refinement part
289 // (which borrows code from DeepFlow). This is inconsistent,
290 // but I guess we're better off with staying with the original
291 // decisions until we actually know having different ones would be better.
295 void exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height);
298 PersistentFBOSet<1> fbos;
301 GLuint sobel_program;
304 GLuint uniform_tex, uniform_image_size;
309 sobel_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
310 sobel_fs_obj = compile_shader(read_file("sobel.frag"), GL_FRAGMENT_SHADER);
311 sobel_program = link_program(sobel_vs_obj, sobel_fs_obj);
313 // Set up the VAO containing all the required position/texcoord data.
314 glCreateVertexArrays(1, &sobel_vao);
315 glBindVertexArray(sobel_vao);
317 GLint position_attrib = glGetAttribLocation(sobel_program, "position");
318 glEnableVertexArrayAttrib(sobel_vao, position_attrib);
319 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
321 uniform_tex = glGetUniformLocation(sobel_program, "tex");
324 void Sobel::exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height)
326 glUseProgram(sobel_program);
327 glBindTextureUnit(0, tex0_view);
328 glBindSampler(0, nearest_sampler);
329 glProgramUniform1i(sobel_program, uniform_tex, 0);
331 glViewport(0, 0, level_width, level_height);
332 fbos.render_to(grad0_tex);
333 glBindVertexArray(sobel_vao);
334 glUseProgram(sobel_program);
336 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
339 // Motion search to find the initial flow. See motion_search.frag for documentation.
343 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);
346 PersistentFBOSet<1> fbos;
348 GLuint motion_vs_obj;
349 GLuint motion_fs_obj;
350 GLuint motion_search_program;
351 GLuint motion_search_vao;
353 GLuint uniform_image_size, uniform_inv_image_size, uniform_inv_prev_level_size;
354 GLuint uniform_image0_tex, uniform_image1_tex, uniform_grad0_tex, uniform_flow_tex;
357 MotionSearch::MotionSearch()
359 motion_vs_obj = compile_shader(read_file("motion_search.vert"), GL_VERTEX_SHADER);
360 motion_fs_obj = compile_shader(read_file("motion_search.frag"), GL_FRAGMENT_SHADER);
361 motion_search_program = link_program(motion_vs_obj, motion_fs_obj);
363 // Set up the VAO containing all the required position/texcoord data.
364 glCreateVertexArrays(1, &motion_search_vao);
365 glBindVertexArray(motion_search_vao);
366 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
368 GLint position_attrib = glGetAttribLocation(motion_search_program, "position");
369 glEnableVertexArrayAttrib(motion_search_vao, position_attrib);
370 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
372 uniform_image_size = glGetUniformLocation(motion_search_program, "image_size");
373 uniform_inv_image_size = glGetUniformLocation(motion_search_program, "inv_image_size");
374 uniform_inv_prev_level_size = glGetUniformLocation(motion_search_program, "inv_prev_level_size");
375 uniform_image0_tex = glGetUniformLocation(motion_search_program, "image0_tex");
376 uniform_image1_tex = glGetUniformLocation(motion_search_program, "image1_tex");
377 uniform_grad0_tex = glGetUniformLocation(motion_search_program, "grad0_tex");
378 uniform_flow_tex = glGetUniformLocation(motion_search_program, "flow_tex");
381 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)
383 glUseProgram(motion_search_program);
385 bind_sampler(motion_search_program, uniform_image0_tex, 0, tex0_view, nearest_sampler);
386 bind_sampler(motion_search_program, uniform_image1_tex, 1, tex1_view, linear_sampler);
387 bind_sampler(motion_search_program, uniform_grad0_tex, 2, grad0_tex, nearest_sampler);
388 bind_sampler(motion_search_program, uniform_flow_tex, 3, flow_tex, linear_sampler);
390 glProgramUniform2f(motion_search_program, uniform_image_size, level_width, level_height);
391 glProgramUniform2f(motion_search_program, uniform_inv_image_size, 1.0f / level_width, 1.0f / level_height);
392 glProgramUniform2f(motion_search_program, uniform_inv_prev_level_size, 1.0f / prev_level_width, 1.0f / prev_level_height);
394 glViewport(0, 0, width_patches, height_patches);
395 fbos.render_to(flow_out_tex);
396 glBindVertexArray(motion_search_vao);
397 glUseProgram(motion_search_program);
398 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
401 // Do “densification”, ie., upsampling of the flow patches to the flow field
402 // (the same size as the image at this level). We draw one quad per patch
403 // over its entire covered area (using instancing in the vertex shader),
404 // and then weight the contributions in the pixel shader by post-warp difference.
405 // This is equation (3) in the paper.
407 // We accumulate the flow vectors in the R/G channels (for u/v) and the total
408 // weight in the B channel. Dividing R and G by B gives the normalized values.
412 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);
415 PersistentFBOSet<1> fbos;
417 GLuint densify_vs_obj;
418 GLuint densify_fs_obj;
419 GLuint densify_program;
422 GLuint uniform_width_patches, uniform_patch_size, uniform_patch_spacing;
423 GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex;
428 densify_vs_obj = compile_shader(read_file("densify.vert"), GL_VERTEX_SHADER);
429 densify_fs_obj = compile_shader(read_file("densify.frag"), GL_FRAGMENT_SHADER);
430 densify_program = link_program(densify_vs_obj, densify_fs_obj);
432 // Set up the VAO containing all the required position/texcoord data.
433 glCreateVertexArrays(1, &densify_vao);
434 glBindVertexArray(densify_vao);
435 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
437 GLint position_attrib = glGetAttribLocation(densify_program, "position");
438 glEnableVertexArrayAttrib(densify_vao, position_attrib);
439 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
441 uniform_width_patches = glGetUniformLocation(densify_program, "width_patches");
442 uniform_patch_size = glGetUniformLocation(densify_program, "patch_size");
443 uniform_patch_spacing = glGetUniformLocation(densify_program, "patch_spacing");
444 uniform_image0_tex = glGetUniformLocation(densify_program, "image0_tex");
445 uniform_image1_tex = glGetUniformLocation(densify_program, "image1_tex");
446 uniform_flow_tex = glGetUniformLocation(densify_program, "flow_tex");
449 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)
451 glUseProgram(densify_program);
453 bind_sampler(densify_program, uniform_image0_tex, 0, tex0_view, nearest_sampler);
454 bind_sampler(densify_program, uniform_image1_tex, 1, tex1_view, linear_sampler);
455 bind_sampler(densify_program, uniform_flow_tex, 2, flow_tex, nearest_sampler);
457 glProgramUniform1i(densify_program, uniform_width_patches, width_patches);
458 glProgramUniform2f(densify_program, uniform_patch_size,
459 float(patch_size_pixels) / level_width,
460 float(patch_size_pixels) / level_height);
462 float patch_spacing_x = float(level_width - patch_size_pixels) / (width_patches - 1);
463 float patch_spacing_y = float(level_height - patch_size_pixels) / (height_patches - 1);
464 if (width_patches == 1) patch_spacing_x = 0.0f; // Avoid infinities.
465 if (height_patches == 1) patch_spacing_y = 0.0f;
466 glProgramUniform2f(densify_program, uniform_patch_spacing,
467 patch_spacing_x / level_width,
468 patch_spacing_y / level_height);
470 glViewport(0, 0, level_width, level_height);
472 glBlendFunc(GL_ONE, GL_ONE);
473 glBindVertexArray(densify_vao);
474 fbos.render_to(dense_flow_tex);
475 glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width_patches * height_patches);
478 // Warp I_1 to I_w, and then compute the mean (I) and difference (I_t) of
479 // I_0 and I_w. The prewarping is what enables us to solve the variational
480 // flow for du,dv instead of u,v.
482 // Also calculates the normalized flow, ie. divides by z (this is needed because
483 // Densify works by additive blending) and multiplies by the image size.
485 // See variational_refinement.txt for more information.
489 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);
492 PersistentFBOSet<3> fbos;
494 GLuint prewarp_vs_obj;
495 GLuint prewarp_fs_obj;
496 GLuint prewarp_program;
499 GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex;
500 GLuint uniform_image_size;
505 prewarp_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
506 prewarp_fs_obj = compile_shader(read_file("prewarp.frag"), GL_FRAGMENT_SHADER);
507 prewarp_program = link_program(prewarp_vs_obj, prewarp_fs_obj);
509 // Set up the VAO containing all the required position/texcoord data.
510 glCreateVertexArrays(1, &prewarp_vao);
511 glBindVertexArray(prewarp_vao);
512 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
514 GLint position_attrib = glGetAttribLocation(prewarp_program, "position");
515 glEnableVertexArrayAttrib(prewarp_vao, position_attrib);
516 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
518 uniform_image0_tex = glGetUniformLocation(prewarp_program, "image0_tex");
519 uniform_image1_tex = glGetUniformLocation(prewarp_program, "image1_tex");
520 uniform_flow_tex = glGetUniformLocation(prewarp_program, "flow_tex");
522 uniform_image_size = glGetUniformLocation(prewarp_program, "image_size");
525 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)
527 glUseProgram(prewarp_program);
529 bind_sampler(prewarp_program, uniform_image0_tex, 0, tex0_view, nearest_sampler);
530 bind_sampler(prewarp_program, uniform_image1_tex, 1, tex1_view, linear_sampler);
531 bind_sampler(prewarp_program, uniform_flow_tex, 2, flow_tex, nearest_sampler);
533 glProgramUniform2f(prewarp_program, uniform_image_size, level_width, level_height);
535 glViewport(0, 0, level_width, level_height);
537 glBindVertexArray(prewarp_vao);
538 fbos.render_to(I_tex, I_t_tex, normalized_flow_tex);
539 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
542 // From I, calculate the partial derivatives I_x and I_y. We use a four-tap
543 // central difference filter, since apparently, that's tradition (I haven't
544 // measured quality versus a more normal 0.5 (I[x+1] - I[x-1]).)
545 // The coefficients come from
547 // https://en.wikipedia.org/wiki/Finite_difference_coefficient
549 // Also computes β_0, since it depends only on I_x and I_y.
553 void exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, int level_width, int level_height);
556 PersistentFBOSet<2> fbos;
558 GLuint derivatives_vs_obj;
559 GLuint derivatives_fs_obj;
560 GLuint derivatives_program;
561 GLuint derivatives_vao;
566 Derivatives::Derivatives()
568 derivatives_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
569 derivatives_fs_obj = compile_shader(read_file("derivatives.frag"), GL_FRAGMENT_SHADER);
570 derivatives_program = link_program(derivatives_vs_obj, derivatives_fs_obj);
572 // Set up the VAO containing all the required position/texcoord data.
573 glCreateVertexArrays(1, &derivatives_vao);
574 glBindVertexArray(derivatives_vao);
575 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
577 GLint position_attrib = glGetAttribLocation(derivatives_program, "position");
578 glEnableVertexArrayAttrib(derivatives_vao, position_attrib);
579 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
581 uniform_tex = glGetUniformLocation(derivatives_program, "tex");
584 void Derivatives::exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, int level_width, int level_height)
586 glUseProgram(derivatives_program);
588 bind_sampler(derivatives_program, uniform_tex, 0, input_tex, nearest_sampler);
590 glViewport(0, 0, level_width, level_height);
592 glBindVertexArray(derivatives_vao);
593 fbos.render_to(I_x_y_tex, beta_0_tex);
594 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
597 // Calculate the smoothness constraints between neighboring pixels;
598 // s_x(x,y) stores smoothness between pixel (x,y) and (x+1,y),
599 // and s_y(x,y) stores between (x,y) and (x,y+1). We'll sample with
600 // border color (0,0) later, so that there's zero diffusion out of
603 // See variational_refinement.txt for more information.
604 class ComputeSmoothness {
607 void exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height);
610 PersistentFBOSet<2> fbos;
612 GLuint smoothness_vs_obj;
613 GLuint smoothness_fs_obj;
614 GLuint smoothness_program;
615 GLuint smoothness_vao;
617 GLuint uniform_flow_tex, uniform_diff_flow_tex;
618 GLuint uniform_alpha;
621 ComputeSmoothness::ComputeSmoothness()
623 smoothness_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
624 smoothness_fs_obj = compile_shader(read_file("smoothness.frag"), GL_FRAGMENT_SHADER);
625 smoothness_program = link_program(smoothness_vs_obj, smoothness_fs_obj);
627 // Set up the VAO containing all the required position/texcoord data.
628 glCreateVertexArrays(1, &smoothness_vao);
629 glBindVertexArray(smoothness_vao);
630 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
632 GLint position_attrib = glGetAttribLocation(smoothness_program, "position");
633 glEnableVertexArrayAttrib(smoothness_vao, position_attrib);
634 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
636 uniform_flow_tex = glGetUniformLocation(smoothness_program, "flow_tex");
637 uniform_diff_flow_tex = glGetUniformLocation(smoothness_program, "diff_flow_tex");
638 uniform_alpha = glGetUniformLocation(smoothness_program, "alpha");
641 void ComputeSmoothness::exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height)
643 glUseProgram(smoothness_program);
645 bind_sampler(smoothness_program, uniform_flow_tex, 0, flow_tex, nearest_sampler);
646 bind_sampler(smoothness_program, uniform_diff_flow_tex, 1, diff_flow_tex, nearest_sampler);
647 glProgramUniform1f(smoothness_program, uniform_alpha, vr_alpha);
649 glViewport(0, 0, level_width, level_height);
652 glBindVertexArray(smoothness_vao);
653 fbos.render_to(smoothness_x_tex, smoothness_y_tex);
654 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
656 // Make sure the smoothness on the right and upper borders is zero.
657 // We could have done this by making (W-1)xH and Wx(H-1) textures instead
658 // (we're sampling smoothness with all-zero border color), but we'd
659 // have to adjust the sampling coordinates, which is annoying.
660 glClearTexSubImage(smoothness_x_tex, 0, level_width - 1, 0, 0, 1, level_height, 1, GL_RED, GL_FLOAT, nullptr);
661 glClearTexSubImage(smoothness_y_tex, 0, 0, level_height - 1, 0, level_width, 1, 1, GL_RED, GL_FLOAT, nullptr);
664 // Set up the equations set (two equations in two unknowns, per pixel).
665 // We store five floats; the three non-redundant elements of the 2x2 matrix (A)
666 // as 32-bit floats, and the two elements on the right-hand side (b) as 16-bit
667 // floats. (Actually, we store the inverse of the diagonal elements, because
668 // we only ever need to divide by them.) This fits into four u32 values;
669 // R, G, B for the matrix (the last element is symmetric) and A for the two b values.
670 // All the values of the energy term (E_I, E_G, E_S), except the smoothness
671 // terms that depend on other pixels, are calculated in one pass.
673 // See variational_refinement.txt for more information.
674 class SetupEquations {
677 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);
680 PersistentFBOSet<1> fbos;
682 GLuint equations_vs_obj;
683 GLuint equations_fs_obj;
684 GLuint equations_program;
685 GLuint equations_vao;
687 GLuint uniform_I_x_y_tex, uniform_I_t_tex;
688 GLuint uniform_diff_flow_tex, uniform_base_flow_tex;
689 GLuint uniform_beta_0_tex;
690 GLuint uniform_smoothness_x_tex, uniform_smoothness_y_tex;
691 GLuint uniform_gamma, uniform_delta;
694 SetupEquations::SetupEquations()
696 equations_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
697 equations_fs_obj = compile_shader(read_file("equations.frag"), GL_FRAGMENT_SHADER);
698 equations_program = link_program(equations_vs_obj, equations_fs_obj);
700 // Set up the VAO containing all the required position/texcoord data.
701 glCreateVertexArrays(1, &equations_vao);
702 glBindVertexArray(equations_vao);
703 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
705 GLint position_attrib = glGetAttribLocation(equations_program, "position");
706 glEnableVertexArrayAttrib(equations_vao, position_attrib);
707 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
709 uniform_I_x_y_tex = glGetUniformLocation(equations_program, "I_x_y_tex");
710 uniform_I_t_tex = glGetUniformLocation(equations_program, "I_t_tex");
711 uniform_diff_flow_tex = glGetUniformLocation(equations_program, "diff_flow_tex");
712 uniform_base_flow_tex = glGetUniformLocation(equations_program, "base_flow_tex");
713 uniform_beta_0_tex = glGetUniformLocation(equations_program, "beta_0_tex");
714 uniform_smoothness_x_tex = glGetUniformLocation(equations_program, "smoothness_x_tex");
715 uniform_smoothness_y_tex = glGetUniformLocation(equations_program, "smoothness_y_tex");
716 uniform_gamma = glGetUniformLocation(equations_program, "gamma");
717 uniform_delta = glGetUniformLocation(equations_program, "delta");
720 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)
722 glUseProgram(equations_program);
724 bind_sampler(equations_program, uniform_I_x_y_tex, 0, I_x_y_tex, nearest_sampler);
725 bind_sampler(equations_program, uniform_I_t_tex, 1, I_t_tex, nearest_sampler);
726 bind_sampler(equations_program, uniform_diff_flow_tex, 2, diff_flow_tex, nearest_sampler);
727 bind_sampler(equations_program, uniform_base_flow_tex, 3, base_flow_tex, nearest_sampler);
728 bind_sampler(equations_program, uniform_beta_0_tex, 4, beta_0_tex, nearest_sampler);
729 bind_sampler(equations_program, uniform_smoothness_x_tex, 5, smoothness_x_tex, smoothness_sampler);
730 bind_sampler(equations_program, uniform_smoothness_y_tex, 6, smoothness_y_tex, smoothness_sampler);
731 glProgramUniform1f(equations_program, uniform_delta, vr_delta);
732 glProgramUniform1f(equations_program, uniform_gamma, vr_gamma);
734 glViewport(0, 0, level_width, level_height);
736 glBindVertexArray(equations_vao);
737 fbos.render_to(equation_tex);
738 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
741 // Actually solve the equation sets made by SetupEquations, by means of
742 // successive over-relaxation (SOR).
744 // See variational_refinement.txt for more information.
748 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);
751 PersistentFBOSet<1> fbos;
758 GLuint uniform_diff_flow_tex;
759 GLuint uniform_equation_tex;
760 GLuint uniform_smoothness_x_tex, uniform_smoothness_y_tex;
765 sor_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
766 sor_fs_obj = compile_shader(read_file("sor.frag"), GL_FRAGMENT_SHADER);
767 sor_program = link_program(sor_vs_obj, sor_fs_obj);
769 // Set up the VAO containing all the required position/texcoord data.
770 glCreateVertexArrays(1, &sor_vao);
771 glBindVertexArray(sor_vao);
772 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
774 GLint position_attrib = glGetAttribLocation(sor_program, "position");
775 glEnableVertexArrayAttrib(sor_vao, position_attrib);
776 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
778 uniform_diff_flow_tex = glGetUniformLocation(sor_program, "diff_flow_tex");
779 uniform_equation_tex = glGetUniformLocation(sor_program, "equation_tex");
780 uniform_smoothness_x_tex = glGetUniformLocation(sor_program, "smoothness_x_tex");
781 uniform_smoothness_y_tex = glGetUniformLocation(sor_program, "smoothness_y_tex");
784 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)
786 glUseProgram(sor_program);
788 bind_sampler(sor_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler);
789 bind_sampler(sor_program, uniform_smoothness_x_tex, 1, smoothness_x_tex, smoothness_sampler);
790 bind_sampler(sor_program, uniform_smoothness_y_tex, 2, smoothness_y_tex, smoothness_sampler);
791 bind_sampler(sor_program, uniform_equation_tex, 3, equation_tex, nearest_sampler);
793 glViewport(0, 0, level_width, level_height);
795 glBindVertexArray(sor_vao);
796 fbos.render_to(diff_flow_tex); // NOTE: Bind to same as we render from!
798 for (int i = 0; i < num_iterations; ++i) {
799 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
800 if (i != num_iterations - 1) {
806 // Simply add the differential flow found by the variational refinement to the base flow.
807 // The output is in base_flow_tex; we don't need to make a new texture.
811 void exec(GLuint base_flow_tex, GLuint diff_flow_tex, int level_width, int level_height);
814 PersistentFBOSet<1> fbos;
816 GLuint add_flow_vs_obj;
817 GLuint add_flow_fs_obj;
818 GLuint add_flow_program;
821 GLuint uniform_diff_flow_tex;
824 AddBaseFlow::AddBaseFlow()
826 add_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
827 add_flow_fs_obj = compile_shader(read_file("add_base_flow.frag"), GL_FRAGMENT_SHADER);
828 add_flow_program = link_program(add_flow_vs_obj, add_flow_fs_obj);
830 // Set up the VAO containing all the required position/texcoord data.
831 glCreateVertexArrays(1, &add_flow_vao);
832 glBindVertexArray(add_flow_vao);
833 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
835 GLint position_attrib = glGetAttribLocation(add_flow_program, "position");
836 glEnableVertexArrayAttrib(add_flow_vao, position_attrib);
837 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
839 uniform_diff_flow_tex = glGetUniformLocation(add_flow_program, "diff_flow_tex");
842 void AddBaseFlow::exec(GLuint base_flow_tex, GLuint diff_flow_tex, int level_width, int level_height)
844 glUseProgram(add_flow_program);
846 bind_sampler(add_flow_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler);
848 glViewport(0, 0, level_width, level_height);
850 glBlendFunc(GL_ONE, GL_ONE);
851 glBindVertexArray(add_flow_vao);
852 fbos.render_to(base_flow_tex);
854 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
857 // Take a copy of the flow, bilinearly interpolated and scaled up.
861 void exec(GLuint in_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height);
864 PersistentFBOSet<1> fbos;
866 GLuint resize_flow_vs_obj;
867 GLuint resize_flow_fs_obj;
868 GLuint resize_flow_program;
869 GLuint resize_flow_vao;
871 GLuint uniform_flow_tex;
872 GLuint uniform_scale_factor;
875 ResizeFlow::ResizeFlow()
877 resize_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
878 resize_flow_fs_obj = compile_shader(read_file("resize_flow.frag"), GL_FRAGMENT_SHADER);
879 resize_flow_program = link_program(resize_flow_vs_obj, resize_flow_fs_obj);
881 // Set up the VAO containing all the required position/texcoord data.
882 glCreateVertexArrays(1, &resize_flow_vao);
883 glBindVertexArray(resize_flow_vao);
884 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
886 GLint position_attrib = glGetAttribLocation(resize_flow_program, "position");
887 glEnableVertexArrayAttrib(resize_flow_vao, position_attrib);
888 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
890 uniform_flow_tex = glGetUniformLocation(resize_flow_program, "flow_tex");
891 uniform_scale_factor = glGetUniformLocation(resize_flow_program, "scale_factor");
894 void ResizeFlow::exec(GLuint flow_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height)
896 glUseProgram(resize_flow_program);
898 bind_sampler(resize_flow_program, uniform_flow_tex, 0, flow_tex, nearest_sampler);
900 glProgramUniform2f(resize_flow_program, uniform_scale_factor, float(output_width) / input_width, float(output_height) / input_height);
902 glViewport(0, 0, output_width, output_height);
904 glBindVertexArray(resize_flow_vao);
905 fbos.render_to(out_tex);
907 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
913 pair<GLuint, GLuint> begin_timer(const string &name, int level);
919 pair<GLuint, GLuint> query;
921 vector<Timer> timers;
924 pair<GLuint, GLuint> GPUTimers::begin_timer(const string &name, int level)
927 glGenQueries(2, queries);
928 glQueryCounter(queries[0], GL_TIMESTAMP);
933 timer.query.first = queries[0];
934 timer.query.second = queries[1];
935 timers.push_back(timer);
939 void GPUTimers::print()
941 for (const Timer &timer : timers) {
942 // NOTE: This makes the CPU wait for the GPU.
943 GLuint64 time_start, time_end;
944 glGetQueryObjectui64v(timer.query.first, GL_QUERY_RESULT, &time_start);
945 glGetQueryObjectui64v(timer.query.second, GL_QUERY_RESULT, &time_end);
946 //fprintf(stderr, "GPU time used = %.1f ms\n", time_elapsed / 1e6);
947 for (int i = 0; i < timer.level * 2; ++i) {
948 fprintf(stderr, " ");
950 fprintf(stderr, "%-30s %4.1f ms\n", timer.name.c_str(), GLint64(time_end - time_start) / 1e6);
954 // A simple RAII class for timing until the end of the scope.
957 ScopedTimer(const string &name, GPUTimers *timers)
958 : timers(timers), level(0)
960 query = timers->begin_timer(name, level);
963 ScopedTimer(const string &name, ScopedTimer *parent_timer)
964 : timers(parent_timer->timers),
965 level(parent_timer->level + 1)
967 query = timers->begin_timer(name, level);
978 glQueryCounter(query.second, GL_TIMESTAMP);
986 pair<GLuint, GLuint> query;
990 class DISComputeFlow {
992 DISComputeFlow(int width, int height);
994 // Returns a texture that must be released with release_texture()
996 GLuint exec(GLuint tex0, GLuint tex1);
997 void release_texture(GLuint tex);
1001 GLuint initial_flow_tex;
1003 // The various passes.
1005 MotionSearch motion_search;
1008 Derivatives derivatives;
1009 ComputeSmoothness compute_smoothness;
1010 SetupEquations setup_equations;
1012 AddBaseFlow add_base_flow;
1013 ResizeFlow resize_flow;
1018 GLuint width, height;
1019 bool in_use = false;
1021 vector<Texture> textures;
1023 GLuint get_texture(GLenum format, GLuint width, GLuint height);
1026 DISComputeFlow::DISComputeFlow(int width, int height)
1027 : width(width), height(height)
1029 // Make some samplers.
1030 glCreateSamplers(1, &nearest_sampler);
1031 glSamplerParameteri(nearest_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
1032 glSamplerParameteri(nearest_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
1033 glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
1034 glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
1036 glCreateSamplers(1, &linear_sampler);
1037 glSamplerParameteri(linear_sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
1038 glSamplerParameteri(linear_sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
1039 glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
1040 glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
1042 // The smoothness is sampled so that once we get to a smoothness involving
1043 // a value outside the border, the diffusivity between the two becomes zero.
1044 glCreateSamplers(1, &smoothness_sampler);
1045 glSamplerParameteri(smoothness_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
1046 glSamplerParameteri(smoothness_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
1047 glSamplerParameteri(smoothness_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
1048 glSamplerParameteri(smoothness_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
1049 float zero[] = { 0.0f, 0.0f, 0.0f, 0.0f };
1050 glSamplerParameterfv(smoothness_sampler, GL_TEXTURE_BORDER_COLOR, zero);
1052 // Initial flow is zero, 1x1.
1053 glCreateTextures(GL_TEXTURE_2D, 1, &initial_flow_tex);
1054 glTextureStorage2D(initial_flow_tex, 1, GL_RG16F, 1, 1);
1055 glClearTexImage(initial_flow_tex, 0, GL_RG, GL_FLOAT, nullptr);
1058 GLuint DISComputeFlow::exec(GLuint tex0, GLuint tex1)
1060 for (const Texture &tex : textures) {
1061 assert(!tex.in_use);
1064 int prev_level_width = 1, prev_level_height = 1;
1065 GLuint prev_level_flow_tex = initial_flow_tex;
1069 ScopedTimer total_timer("Total", &timers);
1070 for (int level = coarsest_level; level >= int(finest_level); --level) {
1071 char timer_name[256];
1072 snprintf(timer_name, sizeof(timer_name), "Level %d", level);
1073 ScopedTimer level_timer(timer_name, &total_timer);
1075 int level_width = width >> level;
1076 int level_height = height >> level;
1077 float patch_spacing_pixels = patch_size_pixels * (1.0f - patch_overlap_ratio);
1078 int width_patches = 1 + lrintf((level_width - patch_size_pixels) / patch_spacing_pixels);
1079 int height_patches = 1 + lrintf((level_height - patch_size_pixels) / patch_spacing_pixels);
1081 // Make sure we always read from the correct level; the chosen
1082 // mipmapping could otherwise be rather unpredictable, especially
1083 // during motion search.
1084 // TODO: create these beforehand, and stop leaking them.
1085 GLuint tex0_view, tex1_view;
1086 glGenTextures(1, &tex0_view);
1087 glTextureView(tex0_view, GL_TEXTURE_2D, tex0, GL_R8, level, 1, 0, 1);
1088 glGenTextures(1, &tex1_view);
1089 glTextureView(tex1_view, GL_TEXTURE_2D, tex1, GL_R8, level, 1, 0, 1);
1091 // Create a new texture; we could be fancy and render use a multi-level
1092 // texture, but meh.
1093 GLuint grad0_tex = get_texture(GL_RG16F, level_width, level_height);
1095 // Find the derivative.
1097 ScopedTimer timer("Sobel", &level_timer);
1098 sobel.exec(tex0_view, grad0_tex, level_width, level_height);
1101 // Motion search to find the initial flow. We use the flow from the previous
1102 // level (sampled bilinearly; no fancy tricks) as a guide, then search from there.
1104 // Create an output flow texture.
1105 GLuint flow_out_tex = get_texture(GL_RGB16F, width_patches, height_patches);
1109 ScopedTimer timer("Motion search", &level_timer);
1110 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);
1112 release_texture(grad0_tex);
1116 // Set up an output texture (initially zero).
1117 GLuint dense_flow_tex = get_texture(GL_RGB16F, level_width, level_height);
1118 glClearTexImage(dense_flow_tex, 0, GL_RGB, GL_FLOAT, nullptr);
1122 ScopedTimer timer("Densification", &level_timer);
1123 densify.exec(tex0_view, tex1_view, flow_out_tex, dense_flow_tex, level_width, level_height, width_patches, height_patches);
1125 release_texture(flow_out_tex);
1127 // Everything below here in the loop belongs to variational refinement.
1128 ScopedTimer varref_timer("Variational refinement", &level_timer);
1130 // Prewarping; create I and I_t, and a normalized base flow (so we don't
1131 // have to normalize it over and over again, and also save some bandwidth).
1133 // During the entire rest of the variational refinement, flow will be measured
1134 // in pixels, not 0..1 normalized OpenGL texture coordinates.
1135 // This is because variational refinement depends so heavily on derivatives,
1136 // which are measured in intensity levels per pixel.
1137 GLuint I_tex = get_texture(GL_R16F, level_width, level_height);
1138 GLuint I_t_tex = get_texture(GL_R16F, level_width, level_height);
1139 GLuint base_flow_tex = get_texture(GL_RG16F, level_width, level_height);
1141 ScopedTimer timer("Prewarping", &varref_timer);
1142 prewarp.exec(tex0_view, tex1_view, dense_flow_tex, I_tex, I_t_tex, base_flow_tex, level_width, level_height);
1144 release_texture(dense_flow_tex);
1146 // Calculate I_x and I_y. We're only calculating first derivatives;
1147 // the others will be taken on-the-fly in order to sample from fewer
1148 // textures overall, since sampling from the L1 cache is cheap.
1149 // (TODO: Verify that this is indeed faster than making separate
1150 // double-derivative textures.)
1151 GLuint I_x_y_tex = get_texture(GL_RG16F, level_width, level_height);
1152 GLuint beta_0_tex = get_texture(GL_R16F, level_width, level_height);
1154 ScopedTimer timer("First derivatives", &varref_timer);
1155 derivatives.exec(I_tex, I_x_y_tex, beta_0_tex, level_width, level_height);
1157 release_texture(I_tex);
1159 // We need somewhere to store du and dv (the flow increment, relative
1160 // to the non-refined base flow u0 and v0). It starts at zero.
1161 GLuint du_dv_tex = get_texture(GL_RG16F, level_width, level_height);
1162 glClearTexImage(du_dv_tex, 0, GL_RG, GL_FLOAT, nullptr);
1164 // And for smoothness.
1165 GLuint smoothness_x_tex = get_texture(GL_R16F, level_width, level_height);
1166 GLuint smoothness_y_tex = get_texture(GL_R16F, level_width, level_height);
1168 // And finally for the equation set. See SetupEquations for
1169 // the storage format.
1170 GLuint equation_tex = get_texture(GL_RGBA32UI, level_width, level_height);
1172 for (int outer_idx = 0; outer_idx < level + 1; ++outer_idx) {
1173 // Calculate the smoothness terms between the neighboring pixels,
1174 // both in x and y direction.
1176 ScopedTimer timer("Compute smoothness", &varref_timer);
1177 compute_smoothness.exec(base_flow_tex, du_dv_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height);
1180 // Set up the 2x2 equation system for each pixel.
1182 ScopedTimer timer("Set up equations", &varref_timer);
1183 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);
1186 // Run a few SOR (or quasi-SOR, since we're not really Jacobi) iterations.
1187 // Note that these are to/from the same texture.
1189 ScopedTimer timer("SOR", &varref_timer);
1190 sor.exec(du_dv_tex, equation_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height, 5);
1194 release_texture(I_t_tex);
1195 release_texture(I_x_y_tex);
1196 release_texture(beta_0_tex);
1197 release_texture(smoothness_x_tex);
1198 release_texture(smoothness_y_tex);
1199 release_texture(equation_tex);
1201 // Add the differential flow found by the variational refinement to the base flow,
1202 // giving the final flow estimate for this level.
1203 // The output is in diff_flow_tex; we don't need to make a new texture.
1204 // You can comment out this part if you wish to test disabling of the variational refinement.
1206 ScopedTimer timer("Add differential flow", &varref_timer);
1207 add_base_flow.exec(base_flow_tex, du_dv_tex, level_width, level_height);
1209 release_texture(du_dv_tex);
1211 if (prev_level_flow_tex != initial_flow_tex) {
1212 release_texture(prev_level_flow_tex);
1214 prev_level_flow_tex = base_flow_tex;
1215 prev_level_width = level_width;
1216 prev_level_height = level_height;
1222 // Scale up the flow to the final size (if needed).
1223 if (finest_level == 0) {
1224 return prev_level_flow_tex;
1226 GLuint final_tex = get_texture(GL_RG16F, width, height);
1227 resize_flow.exec(prev_level_flow_tex, final_tex, prev_level_width, prev_level_height, width, height);
1228 release_texture(prev_level_flow_tex);
1233 GLuint DISComputeFlow::get_texture(GLenum format, GLuint width, GLuint height)
1235 for (Texture &tex : textures) {
1236 if (!tex.in_use && tex.format == format &&
1237 tex.width == width && tex.height == height) {
1244 glCreateTextures(GL_TEXTURE_2D, 1, &tex.tex_num);
1245 glTextureStorage2D(tex.tex_num, 1, format, width, height);
1246 tex.format = format;
1248 tex.height = height;
1250 textures.push_back(tex);
1254 void DISComputeFlow::release_texture(GLuint tex_num)
1256 for (Texture &tex : textures) {
1257 if (tex.tex_num == tex_num) {
1266 void write_flow(const char *filename, const float *dense_flow, unsigned width, unsigned height)
1268 FILE *flowfp = fopen(filename, "wb");
1269 fprintf(flowfp, "FEIH");
1270 fwrite(&width, 4, 1, flowfp);
1271 fwrite(&height, 4, 1, flowfp);
1272 for (unsigned y = 0; y < height; ++y) {
1273 int yy = height - y - 1;
1274 for (unsigned x = 0; x < unsigned(width); ++x) {
1275 float du = dense_flow[(yy * width + x) * 2 + 0];
1276 float dv = dense_flow[(yy * width + x) * 2 + 1];
1280 fwrite(&du, 4, 1, flowfp);
1281 fwrite(&dv, 4, 1, flowfp);
1287 void write_ppm(const char *filename, const float *dense_flow, unsigned width, unsigned height)
1289 FILE *fp = fopen(filename, "wb");
1290 fprintf(fp, "P6\n%d %d\n255\n", width, height);
1291 for (unsigned y = 0; y < unsigned(height); ++y) {
1292 int yy = height - y - 1;
1293 for (unsigned x = 0; x < unsigned(width); ++x) {
1294 float du = dense_flow[(yy * width + x) * 2 + 0];
1295 float dv = dense_flow[(yy * width + x) * 2 + 1];
1300 flow2rgb(du, dv, &r, &g, &b);
1309 int main(int argc, char **argv)
1311 static const option long_options[] = {
1312 { "alpha", required_argument, 0, 'a' },
1313 { "delta", required_argument, 0, 'd' },
1314 { "gamma", required_argument, 0, 'g' }
1318 int option_index = 0;
1319 int c = getopt_long(argc, argv, "a:d:g:", long_options, &option_index);
1326 vr_alpha = atof(optarg);
1329 vr_delta = atof(optarg);
1332 vr_gamma = atof(optarg);
1335 fprintf(stderr, "Unknown option '%s'\n", argv[option_index]);
1340 if (SDL_Init(SDL_INIT_EVERYTHING) == -1) {
1341 fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError());
1344 SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
1345 SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0);
1346 SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0);
1347 SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
1349 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
1350 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
1351 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 5);
1352 // SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
1353 SDL_Window *window = SDL_CreateWindow("OpenGL window",
1354 SDL_WINDOWPOS_UNDEFINED,
1355 SDL_WINDOWPOS_UNDEFINED,
1358 SDL_GLContext context = SDL_GL_CreateContext(window);
1359 assert(context != nullptr);
1362 unsigned width1, height1, width2, height2;
1363 GLuint tex0 = load_texture(argc >= (optind + 1) ? argv[optind] : "test1499.png", &width1, &height1);
1364 GLuint tex1 = load_texture(argc >= (optind + 2) ? argv[optind + 1] : "test1500.png", &width2, &height2);
1366 if (width1 != width2 || height1 != height2) {
1367 fprintf(stderr, "Image dimensions don't match (%dx%d versus %dx%d)\n",
1368 width1, height1, width2, height2);
1372 // FIXME: Should be part of DISComputeFlow (but needs to be initialized
1373 // before all the render passes).
1374 float vertices[] = {
1380 glCreateBuffers(1, &vertex_vbo);
1381 glNamedBufferData(vertex_vbo, sizeof(vertices), vertices, GL_STATIC_DRAW);
1382 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
1384 DISComputeFlow compute_flow(width1, height1);
1385 GLuint final_tex = compute_flow.exec(tex0, tex1);
1387 unique_ptr<float[]> dense_flow(new float[width1 * height1 * 2]);
1388 glGetTextureImage(final_tex, 0, GL_RG, GL_FLOAT, width1 * height1 * 2 * sizeof(float), dense_flow.get());
1390 compute_flow.release_texture(final_tex);
1392 write_flow(argc >= (optind + 3) ? argv[optind + 2] : "flow.flo", dense_flow.get(), width1, height1);
1393 write_ppm("flow.ppm", dense_flow.get(), width1, height1);
1397 // See if there are more flows on the command line (ie., more than three arguments),
1398 // and if so, process them.
1399 int num_flows = (argc - optind) / 3;
1400 for (int i = 1; i < num_flows; ++i) {
1401 const char *filename0 = argv[optind + i * 3 + 0];
1402 const char *filename1 = argv[optind + i * 3 + 1];
1403 const char *flow_filename = argv[optind + i * 3 + 2];
1404 fprintf(stderr, "%s %s -> %s\n", filename0, filename1, flow_filename);
1406 GLuint width, height;
1407 GLuint tex0 = load_texture(filename0, &width, &height);
1408 if (width != width1 || height != height1) {
1409 fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n",
1410 filename0, width, height, width1, height1);
1414 GLuint tex1 = load_texture(filename1, &width, &height);
1415 if (width != width1 || height != height1) {
1416 fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n",
1417 filename1, width, height, width1, height1);
1421 GLuint final_tex = compute_flow.exec(tex0, tex1);
1423 unique_ptr<float[]> dense_flow(new float[width * height * 2]);
1424 glGetTextureImage(final_tex, 0, GL_RG, GL_FLOAT, width * height * 2 * sizeof(float), dense_flow.get());
1426 compute_flow.release_texture(final_tex);
1428 write_flow(flow_filename, dense_flow.get(), width, height);
1431 fprintf(stderr, "err = %d\n", glGetError());