9 #include <SDL2/SDL_error.h>
10 #include <SDL2/SDL_events.h>
11 #include <SDL2/SDL_image.h>
12 #include <SDL2/SDL_keyboard.h>
13 #include <SDL2/SDL_mouse.h>
14 #include <SDL2/SDL_video.h>
22 #define BUFFER_OFFSET(i) ((char *)nullptr + (i))
26 // Operating point 3 (10 Hz on CPU, excluding preprocessing).
27 constexpr float patch_overlap_ratio = 0.75f;
28 constexpr unsigned coarsest_level = 5;
29 constexpr unsigned finest_level = 1;
30 constexpr unsigned patch_size_pixels = 12;
32 // Some global OpenGL objects.
33 GLuint nearest_sampler, linear_sampler, mipmap_sampler;
36 string read_file(const string &filename)
38 FILE *fp = fopen(filename.c_str(), "r");
40 perror(filename.c_str());
44 int ret = fseek(fp, 0, SEEK_END);
46 perror("fseek(SEEK_END)");
52 ret = fseek(fp, 0, SEEK_SET);
54 perror("fseek(SEEK_SET)");
60 ret = fread(&str[0], size, 1, fp);
66 fprintf(stderr, "Short read when trying to read %d bytes from %s\n",
67 size, filename.c_str());
76 GLuint compile_shader(const string &shader_src, GLenum type)
78 GLuint obj = glCreateShader(type);
79 const GLchar* source[] = { shader_src.data() };
80 const GLint length[] = { (GLint)shader_src.size() };
81 glShaderSource(obj, 1, source, length);
84 GLchar info_log[4096];
85 GLsizei log_length = sizeof(info_log) - 1;
86 glGetShaderInfoLog(obj, log_length, &log_length, info_log);
87 info_log[log_length] = 0;
88 if (strlen(info_log) > 0) {
89 fprintf(stderr, "Shader compile log: %s\n", info_log);
93 glGetShaderiv(obj, GL_COMPILE_STATUS, &status);
94 if (status == GL_FALSE) {
95 // Add some line numbers to easier identify compile errors.
96 string src_with_lines = "/* 1 */ ";
98 for (char ch : shader_src) {
99 src_with_lines.push_back(ch);
102 snprintf(buf, sizeof(buf), "/* %3zu */ ", ++lineno);
103 src_with_lines += buf;
107 fprintf(stderr, "Failed to compile shader:\n%s\n", src_with_lines.c_str());
115 GLuint load_texture(const char *filename, unsigned width, unsigned height)
117 FILE *fp = fopen(filename, "rb");
122 unique_ptr<uint8_t[]> pix(new uint8_t[width * height]);
123 if (fread(pix.get(), width * height, 1, fp) != 1) {
124 fprintf(stderr, "Short read from %s\n", filename);
129 // Convert to bottom-left origin.
130 for (unsigned y = 0; y < height / 2; ++y) {
131 unsigned y2 = height - 1 - y;
132 swap_ranges(&pix[y * width], &pix[y * width + width], &pix[y2 * width]);
136 for (int w = width, h = height; w > 1 || h > 1; ) {
143 glCreateTextures(GL_TEXTURE_2D, 1, &tex);
144 glTextureStorage2D(tex, levels, GL_R8, width, height);
145 glTextureSubImage2D(tex, 0, 0, 0, width, height, GL_RED, GL_UNSIGNED_BYTE, pix.get());
146 glGenerateTextureMipmap(tex);
151 GLuint link_program(GLuint vs_obj, GLuint fs_obj)
153 GLuint program = glCreateProgram();
154 glAttachShader(program, vs_obj);
155 glAttachShader(program, fs_obj);
156 glLinkProgram(program);
158 glGetProgramiv(program, GL_LINK_STATUS, &success);
159 if (success == GL_FALSE) {
160 GLchar error_log[1024] = {0};
161 glGetProgramInfoLog(program, 1024, nullptr, error_log);
162 fprintf(stderr, "Error linking program: %s\n", error_log);
168 GLuint generate_vbo(GLint size, GLsizeiptr data_size, const GLvoid *data)
171 glCreateBuffers(1, &vbo);
172 glBufferData(GL_ARRAY_BUFFER, data_size, data, GL_STATIC_DRAW);
173 glNamedBufferData(vbo, data_size, data, GL_STATIC_DRAW);
177 GLuint fill_vertex_attribute(GLuint vao, GLuint glsl_program_num, const string &attribute_name, GLint size, GLenum type, GLsizeiptr data_size, const GLvoid *data)
179 int attrib = glGetAttribLocation(glsl_program_num, attribute_name.c_str());
184 GLuint vbo = generate_vbo(size, data_size, data);
186 glBindBuffer(GL_ARRAY_BUFFER, vbo);
187 glEnableVertexArrayAttrib(vao, attrib);
188 glVertexAttribPointer(attrib, size, type, GL_FALSE, 0, BUFFER_OFFSET(0));
189 glBindBuffer(GL_ARRAY_BUFFER, 0);
194 void bind_sampler(GLuint program, const char *uniform_name, GLuint texture_unit, GLuint tex, GLuint sampler)
196 GLint location = glGetUniformLocation(program, uniform_name);
197 if (location == -1) {
201 glBindTextureUnit(texture_unit, tex);
202 glBindSampler(texture_unit, sampler);
203 glProgramUniform1i(program, location, texture_unit);
206 // Compute gradients in every point, used for the motion search.
207 // The DIS paper doesn't actually mention how these are computed,
208 // but seemingly, a 3x3 Sobel operator is used here (at least in
209 // later versions of the code), while a [1 -8 0 8 -1] kernel is
210 // used for all the derivatives in the variational refinement part
211 // (which borrows code from DeepFlow). This is inconsistent,
212 // but I guess we're better off with staying with the original
213 // decisions until we actually know having different ones would be better.
217 void exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height);
222 GLuint sobel_program;
228 sobel_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER);
229 sobel_fs_obj = compile_shader(read_file("sobel.frag"), GL_FRAGMENT_SHADER);
230 sobel_program = link_program(sobel_vs_obj, sobel_fs_obj);
232 // Set up the VAO containing all the required position/texcoord data.
233 glCreateVertexArrays(1, &sobel_vao);
234 glBindVertexArray(sobel_vao);
236 GLint position_attrib = glGetAttribLocation(sobel_program, "position");
237 glEnableVertexArrayAttrib(sobel_vao, position_attrib);
238 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
240 GLint texcoord_attrib = glGetAttribLocation(sobel_program, "texcoord");
241 glEnableVertexArrayAttrib(sobel_vao, texcoord_attrib);
242 glVertexAttribPointer(texcoord_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
245 void Sobel::exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height)
247 glUseProgram(sobel_program);
248 glBindTextureUnit(0, tex0_view);
249 glBindSampler(0, nearest_sampler);
250 glProgramUniform1i(sobel_program, glGetUniformLocation(sobel_program, "tex"), 0);
251 glProgramUniform2f(sobel_program, glGetUniformLocation(sobel_program, "image_size"), level_width, level_height);
252 glProgramUniform2f(sobel_program, glGetUniformLocation(sobel_program, "inv_image_size"), 1.0f / level_width, 1.0f / level_height);
254 GLuint grad0_fbo; // TODO: cleanup
255 glCreateFramebuffers(1, &grad0_fbo);
256 glNamedFramebufferTexture(grad0_fbo, GL_COLOR_ATTACHMENT0, grad0_tex, 0);
258 glViewport(0, 0, level_width, level_height);
259 glBindFramebuffer(GL_FRAMEBUFFER, grad0_fbo);
260 glBindVertexArray(sobel_vao);
261 glUseProgram(sobel_program);
263 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
266 // Motion search to find the initial flow. See motion_search.frag for documentation.
270 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 width_patches, int height_patches);
273 GLuint motion_vs_obj;
274 GLuint motion_fs_obj;
275 GLuint motion_search_program;
276 GLuint motion_search_vao;
279 MotionSearch::MotionSearch()
281 motion_vs_obj = compile_shader(read_file("motion_search.vert"), GL_VERTEX_SHADER);
282 motion_fs_obj = compile_shader(read_file("motion_search.frag"), GL_FRAGMENT_SHADER);
283 motion_search_program = link_program(motion_vs_obj, motion_fs_obj);
285 // Set up the VAO containing all the required position/texcoord data.
286 glCreateVertexArrays(1, &motion_search_vao);
287 glBindVertexArray(motion_search_vao);
288 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
290 GLint position_attrib = glGetAttribLocation(motion_search_program, "position");
291 glEnableVertexArrayAttrib(motion_search_vao, position_attrib);
292 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
294 GLint texcoord_attrib = glGetAttribLocation(motion_search_program, "texcoord");
295 glEnableVertexArrayAttrib(motion_search_vao, texcoord_attrib);
296 glVertexAttribPointer(texcoord_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
299 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 width_patches, int height_patches)
301 glUseProgram(motion_search_program);
303 bind_sampler(motion_search_program, "image0_tex", 0, tex0_view, nearest_sampler);
304 bind_sampler(motion_search_program, "image1_tex", 1, tex1_view, linear_sampler);
305 bind_sampler(motion_search_program, "grad0_tex", 2, grad0_tex, nearest_sampler);
306 bind_sampler(motion_search_program, "flow_tex", 3, flow_tex, linear_sampler);
308 glProgramUniform2f(motion_search_program, glGetUniformLocation(motion_search_program, "image_size"), level_width, level_height);
309 glProgramUniform2f(motion_search_program, glGetUniformLocation(motion_search_program, "inv_image_size"), 1.0f / level_width, 1.0f / level_height);
311 GLuint flow_fbo; // TODO: cleanup
312 glCreateFramebuffers(1, &flow_fbo);
313 glNamedFramebufferTexture(flow_fbo, GL_COLOR_ATTACHMENT0, flow_out_tex, 0);
315 glViewport(0, 0, width_patches, height_patches);
316 glBindFramebuffer(GL_FRAMEBUFFER, flow_fbo);
317 glBindVertexArray(motion_search_vao);
318 glUseProgram(motion_search_program);
319 glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
322 // Do “densification”, ie., upsampling of the flow patches to the flow field
323 // (the same size as the image at this level). We draw one quad per patch
324 // over its entire covered area (using instancing in the vertex shader),
325 // and then weight the contributions in the pixel shader by post-warp difference.
326 // This is equation (3) in the paper.
328 // We accumulate the flow vectors in the R/G channels (for u/v) and the total
329 // weight in the B channel. Dividing R and G by B gives the normalized values.
333 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);
336 GLuint densify_vs_obj;
337 GLuint densify_fs_obj;
338 GLuint densify_program;
344 densify_vs_obj = compile_shader(read_file("densify.vert"), GL_VERTEX_SHADER);
345 densify_fs_obj = compile_shader(read_file("densify.frag"), GL_FRAGMENT_SHADER);
346 densify_program = link_program(densify_vs_obj, densify_fs_obj);
348 // Set up the VAO containing all the required position/texcoord data.
349 glCreateVertexArrays(1, &densify_vao);
350 glBindVertexArray(densify_vao);
351 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
353 GLint position_attrib = glGetAttribLocation(densify_program, "position");
354 glEnableVertexArrayAttrib(densify_vao, position_attrib);
355 glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0));
358 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)
360 glUseProgram(densify_program);
362 bind_sampler(densify_program, "image0_tex", 0, tex0_view, nearest_sampler);
363 bind_sampler(densify_program, "image1_tex", 1, tex1_view, linear_sampler);
364 bind_sampler(densify_program, "flow_tex", 2, flow_tex, nearest_sampler);
366 glProgramUniform1i(densify_program, glGetUniformLocation(densify_program, "width_patches"), width_patches);
367 glProgramUniform2f(densify_program, glGetUniformLocation(densify_program, "patch_size"),
368 float(patch_size_pixels) / level_width,
369 float(patch_size_pixels) / level_height);
371 float patch_spacing_x = float(level_width - patch_size_pixels) / (width_patches - 1);
372 float patch_spacing_y = float(level_height - patch_size_pixels) / (height_patches - 1);
373 glProgramUniform2f(densify_program, glGetUniformLocation(densify_program, "patch_spacing"),
374 patch_spacing_x / level_width,
375 patch_spacing_y / level_height);
377 GLuint dense_flow_fbo; // TODO: cleanup
378 glCreateFramebuffers(1, &dense_flow_fbo);
379 glNamedFramebufferTexture(dense_flow_fbo, GL_COLOR_ATTACHMENT0, dense_flow_tex, 0);
381 glViewport(0, 0, level_width, level_height);
383 glBlendFunc(GL_ONE, GL_ONE);
384 glBindVertexArray(densify_vao);
385 glBindFramebuffer(GL_FRAMEBUFFER, dense_flow_fbo);
386 glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width_patches * height_patches);
391 if (SDL_Init(SDL_INIT_EVERYTHING) == -1) {
392 fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError());
395 SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
396 SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0);
397 SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0);
398 SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
400 SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
401 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4);
402 SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 5);
403 // SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG);
404 SDL_Window *window = SDL_CreateWindow("OpenGL window",
405 SDL_WINDOWPOS_UNDEFINED,
406 SDL_WINDOWPOS_UNDEFINED,
409 SDL_GLContext context = SDL_GL_CreateContext(window);
410 assert(context != nullptr);
413 GLuint tex0 = load_texture("test1499.pgm", WIDTH, HEIGHT);
414 GLuint tex1 = load_texture("test1500.pgm", WIDTH, HEIGHT);
416 // Make some samplers.
417 glCreateSamplers(1, &nearest_sampler);
418 glSamplerParameteri(nearest_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
419 glSamplerParameteri(nearest_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
420 glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
421 glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
423 glCreateSamplers(1, &linear_sampler);
424 glSamplerParameteri(linear_sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
425 glSamplerParameteri(linear_sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
426 glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
427 glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
429 glCreateSamplers(1, &mipmap_sampler);
430 glSamplerParameteri(mipmap_sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
431 glSamplerParameteri(mipmap_sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
432 glSamplerParameteri(mipmap_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
433 glSamplerParameteri(mipmap_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
441 glCreateBuffers(1, &vertex_vbo);
442 glNamedBufferData(vertex_vbo, sizeof(vertices), vertices, GL_STATIC_DRAW);
443 glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
445 // Initial flow is zero, 1x1.
446 GLuint initial_flow_tex;
447 glCreateTextures(GL_TEXTURE_2D, 1, &initial_flow_tex);
448 glTextureStorage2D(initial_flow_tex, 1, GL_RGB32F, 1, 1);
450 GLuint prev_level_flow_tex = initial_flow_tex;
453 MotionSearch motion_search;
456 for (int level = coarsest_level; level >= int(finest_level); --level) {
457 int level_width = WIDTH >> level;
458 int level_height = HEIGHT >> level;
459 float patch_spacing_pixels = patch_size_pixels * (1.0f - patch_overlap_ratio);
460 int width_patches = 1 + lrintf((level_width - patch_size_pixels) / patch_spacing_pixels);
461 int height_patches = 1 + lrintf((level_height - patch_size_pixels) / patch_spacing_pixels);
463 // Make sure we always read from the correct level; the chosen
464 // mipmapping could otherwise be rather unpredictable, especially
465 // during motion search.
466 // TODO: create these beforehand, and stop leaking them.
467 GLuint tex0_view, tex1_view;
468 glGenTextures(1, &tex0_view);
469 glTextureView(tex0_view, GL_TEXTURE_2D, tex0, GL_R8, level, 1, 0, 1);
470 glGenTextures(1, &tex1_view);
471 glTextureView(tex1_view, GL_TEXTURE_2D, tex1, GL_R8, level, 1, 0, 1);
473 // Create a new texture; we could be fancy and render use a multi-level
476 glCreateTextures(GL_TEXTURE_2D, 1, &grad0_tex);
477 glTextureStorage2D(grad0_tex, 1, GL_RG16F, level_width, level_height);
479 // Find the derivative.
480 sobel.exec(tex0_view, grad0_tex, level_width, level_height);
482 // Motion search to find the initial flow. We use the flow from the previous
483 // level (sampled bilinearly; no fancy tricks) as a guide, then search from there.
485 // Create an output flow texture.
487 glCreateTextures(GL_TEXTURE_2D, 1, &flow_out_tex);
488 glTextureStorage2D(flow_out_tex, 1, GL_RG16F, width_patches, height_patches);
491 motion_search.exec(tex0_view, tex1_view, grad0_tex, prev_level_flow_tex, flow_out_tex, level_width, level_height, width_patches, height_patches);
495 // Set up an output texture.
496 GLuint dense_flow_tex;
497 glCreateTextures(GL_TEXTURE_2D, 1, &dense_flow_tex);
498 //glTextureStorage2D(dense_flow_tex, 1, GL_RGB16F, level_width, level_height);
499 glTextureStorage2D(dense_flow_tex, 1, GL_RGBA32F, level_width, level_height);
502 densify.exec(tex0_view, tex1_view, flow_out_tex, dense_flow_tex, level_width, level_height, width_patches, height_patches);
504 // TODO: Variational refinement.
506 prev_level_flow_tex = dense_flow_tex;
509 int level_width = WIDTH >> finest_level;
510 int level_height = HEIGHT >> finest_level;
511 unique_ptr<float[]> dense_flow(new float[level_width * level_height * 3]);
512 glGetTextureImage(prev_level_flow_tex, 0, GL_RGB, GL_FLOAT, level_width * level_height * 3 * sizeof(float), dense_flow.get());
514 FILE *fp = fopen("flow.ppm", "wb");
515 fprintf(fp, "P6\n%d %d\n255\n", level_width, level_height);
516 for (unsigned y = 0; y < unsigned(level_height); ++y) {
517 int yy = level_height - y - 1;
518 for (unsigned x = 0; x < unsigned(level_width); ++x) {
519 float du = dense_flow[(yy * level_width + x) * 3 + 0];
520 float dv = dense_flow[(yy * level_width + x) * 3 + 1];
521 float w = dense_flow[(yy * level_width + x) * 3 + 2];
526 float angle = atan2(dv * level_width, du * level_height);
527 float magnitude = min(hypot(du * level_width, dv * level_height) / 20.0, 1.0);
529 // HSV to RGB (from Wikipedia). Saturation is 1.
531 float h = (angle + M_PI) * 6.0 / (2.0 * M_PI);
532 float X = c * (1.0 - fabs(fmod(h, 2.0) - 1.0));
533 float r = 0.0f, g = 0.0f, b = 0.0f;
536 } else if (h < 2.0f) {
538 } else if (h < 3.0f) {
540 } else if (h < 4.0f) {
542 } else if (h < 5.0f) {
544 } else if (h < 6.0f) {
547 // h is NaN, so black is fine.
549 float m = magnitude - c;
550 r += m; g += m; b += m;
551 r = max(min(r, 1.0f), 0.0f);
552 g = max(min(g, 1.0f), 0.0f);
553 b = max(min(b, 1.0f), 0.0f);
554 putc(lrintf(r * 255.0f), fp);
555 putc(lrintf(g * 255.0f), fp);
556 putc(lrintf(b * 255.0f), fp);
561 fprintf(stderr, "err = %d\n", glGetError());