X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=flow.cpp;h=b5e77627f1826d1b59e98cbd131ac3d4472932d3;hb=243df025f82d7ba53f71ed2b8613326a7d35415f;hp=2ddaf58dd6b78abb3c51db830b2e674433a16b56;hpb=69893e7cf5624e9d25fdd8b617b6d9054ac276e7;p=nageru diff --git a/flow.cpp b/flow.cpp index 2ddaf58..b5e7762 100644 --- a/flow.cpp +++ b/flow.cpp @@ -1,8 +1,5 @@ #define NO_SDL_GLEXT 1 -#define WIDTH 1280 -#define HEIGHT 720 - #include #include @@ -14,10 +11,16 @@ #include #include +#include #include +#include + +#include "util.h" #include #include +#include +#include #define BUFFER_OFFSET(i) ((char *)nullptr + (i)) @@ -25,10 +28,20 @@ using namespace std; // Operating point 3 (10 Hz on CPU, excluding preprocessing). constexpr float patch_overlap_ratio = 0.75f; -constexpr unsigned coarsest_level = 0; -constexpr unsigned finest_level = 0; +constexpr unsigned coarsest_level = 5; +constexpr unsigned finest_level = 1; constexpr unsigned patch_size_pixels = 12; +// Weighting constants for the different parts of the variational refinement. +// These don't correspond 1:1 to the values given in the DIS paper, +// since we have different normalizations and ranges in some cases. +float vr_gamma = 10.0f, vr_delta = 5.0f, vr_alpha = 10.0f; + +// Some global OpenGL objects. +// TODO: These should really be part of DISComputeFlow. +GLuint nearest_sampler, linear_sampler, smoothness_sampler; +GLuint vertex_vbo; + string read_file(const string &filename) { FILE *fp = fopen(filename.c_str(), "r"); @@ -107,26 +120,41 @@ GLuint compile_shader(const string &shader_src, GLenum type) return obj; } - -GLuint load_texture(const char *filename, unsigned width, unsigned height) +GLuint load_texture(const char *filename, unsigned *width_ret, unsigned *height_ret) { - FILE *fp = fopen(filename, "rb"); - if (fp == nullptr) { - perror(filename); + SDL_Surface *surf = IMG_Load(filename); + if (surf == nullptr) { + fprintf(stderr, "IMG_Load(%s): %s\n", filename, IMG_GetError()); exit(1); } - unique_ptr pix(new uint8_t[width * height]); - if (fread(pix.get(), width * height, 1, fp) != 1) { - fprintf(stderr, "Short read from %s\n", filename); + + // For whatever reason, SDL doesn't support converting to YUV surfaces + // nor grayscale, so we'll do it (slowly) ourselves. + SDL_Surface *rgb_surf = SDL_ConvertSurfaceFormat(surf, SDL_PIXELFORMAT_RGBA8888, /*flags=*/0); + if (rgb_surf == nullptr) { + fprintf(stderr, "SDL_ConvertSurfaceFormat(%s): %s\n", filename, SDL_GetError()); exit(1); } - fclose(fp); - // Convert to bottom-left origin. - for (unsigned y = 0; y < height / 2; ++y) { + SDL_FreeSurface(surf); + + unsigned width = rgb_surf->w, height = rgb_surf->h; + const uint8_t *sptr = (uint8_t *)rgb_surf->pixels; + unique_ptr pix(new uint8_t[width * height]); + + // Extract the Y component, and convert to bottom-left origin. + for (unsigned y = 0; y < height; ++y) { unsigned y2 = height - 1 - y; - swap_ranges(&pix[y * width], &pix[y * width + width], &pix[y2 * width]); + for (unsigned x = 0; x < width; ++x) { + uint8_t r = sptr[(y2 * width + x) * 4 + 3]; + uint8_t g = sptr[(y2 * width + x) * 4 + 2]; + uint8_t b = sptr[(y2 * width + x) * 4 + 1]; + + // Rec. 709. + pix[y * width + x] = lrintf(r * 0.2126f + g * 0.7152f + b * 0.0722f); + } } + SDL_FreeSurface(rgb_surf); int levels = 1; for (int w = width, h = height; w > 1 || h > 1; ) { @@ -141,15 +169,18 @@ GLuint load_texture(const char *filename, unsigned width, unsigned height) glTextureSubImage2D(tex, 0, 0, 0, width, height, GL_RED, GL_UNSIGNED_BYTE, pix.get()); glGenerateTextureMipmap(tex); + *width_ret = width; + *height_ret = height; + return tex; } GLuint link_program(GLuint vs_obj, GLuint fs_obj) { - GLuint program = glCreateProgram(); - glAttachShader(program, vs_obj); - glAttachShader(program, fs_obj); - glLinkProgram(program); + GLuint program = glCreateProgram(); + glAttachShader(program, vs_obj); + glAttachShader(program, fs_obj); + glLinkProgram(program); GLint success; glGetProgramiv(program, GL_LINK_STATUS, &success); if (success == GL_FALSE) { @@ -187,9 +218,8 @@ GLuint fill_vertex_attribute(GLuint vao, GLuint glsl_program_num, const string & return vbo; } -void bind_sampler(GLuint program, const char *uniform_name, GLuint texture_unit, GLuint tex, GLuint sampler) +void bind_sampler(GLuint program, GLint location, GLuint texture_unit, GLuint tex, GLuint sampler) { - GLint location = glGetUniformLocation(program, uniform_name); if (location == -1) { return; } @@ -199,302 +229,1168 @@ void bind_sampler(GLuint program, const char *uniform_name, GLuint texture_unit, glProgramUniform1i(program, location, texture_unit); } -int main(void) -{ - if (SDL_Init(SDL_INIT_EVERYTHING) == -1) { - fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError()); - exit(1); +// A class that caches FBOs that render to a given set of textures. +// It never frees anything, so it is only suitable for rendering to +// the same (small) set of textures over and over again. +template +class PersistentFBOSet { +public: + void render_to(const array &textures); + + // Convenience wrappers. + void render_to(GLuint texture0, enable_if * = nullptr) { + render_to({{texture0}}); } - SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8); - SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0); - SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0); - SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1); - SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE); - SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4); - SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 5); - // SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG); - SDL_Window *window = SDL_CreateWindow("OpenGL window", - SDL_WINDOWPOS_UNDEFINED, - SDL_WINDOWPOS_UNDEFINED, - 64, 64, - SDL_WINDOW_OPENGL); - SDL_GLContext context = SDL_GL_CreateContext(window); - assert(context != nullptr); + void render_to(GLuint texture0, GLuint texture1, enable_if * = nullptr) { + render_to({{texture0, texture1}}); + } - // Load pictures. - GLuint tex0 = load_texture("test1499.pgm", WIDTH, HEIGHT); - GLuint tex1 = load_texture("test1500.pgm", WIDTH, HEIGHT); + void render_to(GLuint texture0, GLuint texture1, GLuint texture2, enable_if * = nullptr) { + render_to({{texture0, texture1, texture2}}); + } - // Load shaders. - GLuint motion_vs_obj = compile_shader(read_file("motion_search.vert"), GL_VERTEX_SHADER); - GLuint motion_fs_obj = compile_shader(read_file("motion_search.frag"), GL_FRAGMENT_SHADER); - GLuint motion_search_program = link_program(motion_vs_obj, motion_fs_obj); + void render_to(GLuint texture0, GLuint texture1, GLuint texture2, GLuint texture3, enable_if * = nullptr) { + render_to({{texture0, texture1, texture2, texture3}}); + } - GLuint sobel_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER); - GLuint sobel_fs_obj = compile_shader(read_file("sobel.frag"), GL_FRAGMENT_SHADER); - GLuint sobel_program = link_program(sobel_vs_obj, sobel_fs_obj); +private: + // TODO: Delete these on destruction. + map, GLuint> fbos; +}; - GLuint densify_vs_obj = compile_shader(read_file("densify.vert"), GL_VERTEX_SHADER); - GLuint densify_fs_obj = compile_shader(read_file("densify.frag"), GL_FRAGMENT_SHADER); - GLuint densify_program = link_program(densify_vs_obj, densify_fs_obj); +template +void PersistentFBOSet::render_to(const array &textures) +{ + auto it = fbos.find(textures); + if (it != fbos.end()) { + glBindFramebuffer(GL_FRAMEBUFFER, it->second); + return; + } - // Make some samplers. - GLuint nearest_sampler; - glCreateSamplers(1, &nearest_sampler); - glSamplerParameteri(nearest_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST); - glSamplerParameteri(nearest_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST); - glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); - glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); + GLuint fbo; + glCreateFramebuffers(1, &fbo); + GLenum bufs[num_elements]; + for (size_t i = 0; i < num_elements; ++i) { + glNamedFramebufferTexture(fbo, GL_COLOR_ATTACHMENT0 + i, textures[i], 0); + bufs[i] = GL_COLOR_ATTACHMENT0 + i; + } + glNamedFramebufferDrawBuffers(fbo, num_elements, bufs); - GLuint linear_sampler; - glCreateSamplers(1, &linear_sampler); - glSamplerParameteri(linear_sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR); - glSamplerParameteri(linear_sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR); - glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); - glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); + fbos[textures] = fbo; + glBindFramebuffer(GL_FRAMEBUFFER, fbo); +} - GLuint mipmap_sampler; - glCreateSamplers(1, &mipmap_sampler); - glSamplerParameteri(mipmap_sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST); - glSamplerParameteri(mipmap_sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR); - glSamplerParameteri(mipmap_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); - glSamplerParameteri(mipmap_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); - - // Coarsest level. - int level = coarsest_level; - int level_width = WIDTH >> level; - int level_height = HEIGHT >> level; - float patch_spacing_pixels = patch_size_pixels * (1.0f - patch_overlap_ratio); - int width_patches = 1 + lrintf((level_width - patch_size_pixels) / patch_spacing_pixels); - int height_patches = 1 + lrintf((level_height - patch_size_pixels) / patch_spacing_pixels); - - // Make sure we always read from the correct level; the chosen - // mipmapping could otherwise be rather unpredictable, especially - // during motion search. - GLuint tex0_view, tex1_view; - glGenTextures(1, &tex0_view); - glTextureView(tex0_view, GL_TEXTURE_2D, tex0, GL_R8, level, 1, 0, 1); - glGenTextures(1, &tex1_view); - glTextureView(tex1_view, GL_TEXTURE_2D, tex1, GL_R8, level, 1, 0, 1); - - // Compute gradients in every point, used for the motion search. - // The DIS paper doesn't actually mention how these are computed, - // but seemingly, a 3x3 Sobel operator is used here (at least in - // later versions of the code), while a [1 -8 0 8 -1] kernel is - // used for all the derivatives in the variational refinement part - // (which borrows code from DeepFlow). This is inconsistent, - // but I guess we're better off with staying with the original - // decisions until we actually know having different ones would be better. - - // Create a new texture; we could be fancy and render use a multi-level - // texture, but meh. - GLuint grad0_tex; - glCreateTextures(GL_TEXTURE_2D, 1, &grad0_tex); - glTextureStorage2D(grad0_tex, 1, GL_RG16F, level_width, level_height); - - GLuint grad0_fbo; - glCreateFramebuffers(1, &grad0_fbo); - glNamedFramebufferTexture(grad0_fbo, GL_COLOR_ATTACHMENT0, grad0_tex, 0); +// Compute gradients in every point, used for the motion search. +// The DIS paper doesn't actually mention how these are computed, +// but seemingly, a 3x3 Sobel operator is used here (at least in +// later versions of the code), while a [1 -8 0 8 -1] kernel is +// used for all the derivatives in the variational refinement part +// (which borrows code from DeepFlow). This is inconsistent, +// but I guess we're better off with staying with the original +// decisions until we actually know having different ones would be better. +class Sobel { +public: + Sobel(); + void exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height); + +private: + PersistentFBOSet<1> fbos; + GLuint sobel_vs_obj; + GLuint sobel_fs_obj; + GLuint sobel_program; + GLuint sobel_vao; - glUseProgram(sobel_program); - glBindTextureUnit(0, tex0_view); - glBindSampler(0, nearest_sampler); - glProgramUniform1i(sobel_program, glGetUniformLocation(sobel_program, "tex"), 0); - glProgramUniform1f(sobel_program, glGetUniformLocation(sobel_program, "inv_width"), 1.0f / level_width); - glProgramUniform1f(sobel_program, glGetUniformLocation(sobel_program, "inv_height"), 1.0f / level_height); + GLuint uniform_tex, uniform_image_size; +}; + +Sobel::Sobel() +{ + sobel_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER); + sobel_fs_obj = compile_shader(read_file("sobel.frag"), GL_FRAGMENT_SHADER); + sobel_program = link_program(sobel_vs_obj, sobel_fs_obj); // Set up the VAO containing all the required position/texcoord data. - GLuint sobel_vao; - glCreateVertexArrays(1, &sobel_vao); - glBindVertexArray(sobel_vao); - float vertices[] = { - 0.0f, 1.0f, - 0.0f, 0.0f, - 1.0f, 1.0f, - 1.0f, 0.0f, - }; - GLuint vertex_vbo; - glCreateBuffers(1, &vertex_vbo); - glNamedBufferData(vertex_vbo, sizeof(vertices), vertices, GL_STATIC_DRAW); - glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + glCreateVertexArrays(1, &sobel_vao); + glBindVertexArray(sobel_vao); - int position_attrib = glGetAttribLocation(sobel_program, "position"); + GLint position_attrib = glGetAttribLocation(sobel_program, "position"); glEnableVertexArrayAttrib(sobel_vao, position_attrib); glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); - int texcoord_attrib = glGetAttribLocation(sobel_program, "texcoord"); - glEnableVertexArrayAttrib(sobel_vao, texcoord_attrib); - glVertexAttribPointer(texcoord_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + uniform_tex = glGetUniformLocation(sobel_program, "tex"); +} - glBindBuffer(GL_ARRAY_BUFFER, 0); +void Sobel::exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height) +{ + glUseProgram(sobel_program); + glBindTextureUnit(0, tex0_view); + glBindSampler(0, nearest_sampler); + glProgramUniform1i(sobel_program, uniform_tex, 0); - // Now finally draw. glViewport(0, 0, level_width, level_height); - glBindFramebuffer(GL_FRAMEBUFFER, grad0_fbo); + fbos.render_to(grad0_tex); + glBindVertexArray(sobel_vao); glUseProgram(sobel_program); glDisable(GL_BLEND); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +} - // Motion search to find the initial flow. - - // Create a flow texture, initialized to zero. - GLuint flow_tex; - glCreateTextures(GL_TEXTURE_2D, 1, &flow_tex); - glTextureStorage2D(flow_tex, 1, GL_RG16F, width_patches, height_patches); - - // And an output flow texture. (Well, we could have used texture barriers, - // but I don't feel lucky today.) - GLuint flow_out_tex; - glCreateTextures(GL_TEXTURE_2D, 1, &flow_out_tex); - glTextureStorage2D(flow_out_tex, 1, GL_RG16F, width_patches, height_patches); - - GLuint flow_fbo; - glCreateFramebuffers(1, &flow_fbo); - glNamedFramebufferTexture(flow_fbo, GL_COLOR_ATTACHMENT0, flow_out_tex, 0); +// Motion search to find the initial flow. See motion_search.frag for documentation. +class MotionSearch { +public: + MotionSearch(); + 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); - glUseProgram(motion_search_program); +private: + PersistentFBOSet<1> fbos; - bind_sampler(motion_search_program, "image0_tex", 0, tex0_view, nearest_sampler); - bind_sampler(motion_search_program, "image1_tex", 1, tex1_view, linear_sampler); - bind_sampler(motion_search_program, "grad0_tex", 2, grad0_tex, nearest_sampler); - bind_sampler(motion_search_program, "flow_tex", 3, flow_tex, nearest_sampler); + GLuint motion_vs_obj; + GLuint motion_fs_obj; + GLuint motion_search_program; + GLuint motion_search_vao; - glProgramUniform1f(motion_search_program, glGetUniformLocation(motion_search_program, "image_width"), level_width); - glProgramUniform1f(motion_search_program, glGetUniformLocation(motion_search_program, "image_height"), level_height); - glProgramUniform1f(motion_search_program, glGetUniformLocation(motion_search_program, "inv_image_width"), 1.0f / level_width); - glProgramUniform1f(motion_search_program, glGetUniformLocation(motion_search_program, "inv_image_height"), 1.0f / level_height); + GLuint uniform_image_size, uniform_inv_image_size, uniform_inv_prev_level_size; + GLuint uniform_image0_tex, uniform_image1_tex, uniform_grad0_tex, uniform_flow_tex; +}; -// printf("%d x %d patches on this level\n", width_patches, height_patches); +MotionSearch::MotionSearch() +{ + motion_vs_obj = compile_shader(read_file("motion_search.vert"), GL_VERTEX_SHADER); + motion_fs_obj = compile_shader(read_file("motion_search.frag"), GL_FRAGMENT_SHADER); + motion_search_program = link_program(motion_vs_obj, motion_fs_obj); // Set up the VAO containing all the required position/texcoord data. - GLuint motion_search_vao; - glCreateVertexArrays(1, &motion_search_vao); - glBindVertexArray(motion_search_vao); + glCreateVertexArrays(1, &motion_search_vao); + glBindVertexArray(motion_search_vao); glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); - position_attrib = glGetAttribLocation(motion_search_program, "position"); + GLint position_attrib = glGetAttribLocation(motion_search_program, "position"); glEnableVertexArrayAttrib(motion_search_vao, position_attrib); glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); - texcoord_attrib = glGetAttribLocation(motion_search_program, "texcoord"); - glEnableVertexArrayAttrib(motion_search_vao, texcoord_attrib); - glVertexAttribPointer(texcoord_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + uniform_image_size = glGetUniformLocation(motion_search_program, "image_size"); + uniform_inv_image_size = glGetUniformLocation(motion_search_program, "inv_image_size"); + uniform_inv_prev_level_size = glGetUniformLocation(motion_search_program, "inv_prev_level_size"); + uniform_image0_tex = glGetUniformLocation(motion_search_program, "image0_tex"); + uniform_image1_tex = glGetUniformLocation(motion_search_program, "image1_tex"); + uniform_grad0_tex = glGetUniformLocation(motion_search_program, "grad0_tex"); + uniform_flow_tex = glGetUniformLocation(motion_search_program, "flow_tex"); +} - glBindBuffer(GL_ARRAY_BUFFER, 0); +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) +{ + glUseProgram(motion_search_program); + + bind_sampler(motion_search_program, uniform_image0_tex, 0, tex0_view, nearest_sampler); + bind_sampler(motion_search_program, uniform_image1_tex, 1, tex1_view, linear_sampler); + bind_sampler(motion_search_program, uniform_grad0_tex, 2, grad0_tex, nearest_sampler); + bind_sampler(motion_search_program, uniform_flow_tex, 3, flow_tex, linear_sampler); + + glProgramUniform2f(motion_search_program, uniform_image_size, level_width, level_height); + glProgramUniform2f(motion_search_program, uniform_inv_image_size, 1.0f / level_width, 1.0f / level_height); + glProgramUniform2f(motion_search_program, uniform_inv_prev_level_size, 1.0f / prev_level_width, 1.0f / prev_level_height); - // And draw. glViewport(0, 0, width_patches, height_patches); - glBindFramebuffer(GL_FRAMEBUFFER, flow_fbo); + fbos.render_to(flow_out_tex); + glBindVertexArray(motion_search_vao); glUseProgram(motion_search_program); glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +} + +// Do “densification”, ie., upsampling of the flow patches to the flow field +// (the same size as the image at this level). We draw one quad per patch +// over its entire covered area (using instancing in the vertex shader), +// and then weight the contributions in the pixel shader by post-warp difference. +// This is equation (3) in the paper. +// +// We accumulate the flow vectors in the R/G channels (for u/v) and the total +// weight in the B channel. Dividing R and G by B gives the normalized values. +class Densify { +public: + Densify(); + 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); + +private: + PersistentFBOSet<1> fbos; + + GLuint densify_vs_obj; + GLuint densify_fs_obj; + GLuint densify_program; + GLuint densify_vao; - // Do “densification”, ie., upsampling of the flow patches to the flow field - // (the same size as the image at this level). We draw one quad per patch - // over its entire covered area (using instancing in the vertex shader), - // and then weight the contributions in the pixel shader by post-warp difference. - // This is equation (3) in the paper. - // - // We accumulate the flow vectors in the R/G channels (for u/v) and the total - // weight in the B channel. Dividing R and G by B gives the normalized values. - - // Set up an output texture. - GLuint dense_flow_tex; - glCreateTextures(GL_TEXTURE_2D, 1, &dense_flow_tex); - //glTextureStorage2D(dense_flow_tex, 1, GL_RGB16F, level_width, level_height); - glTextureStorage2D(dense_flow_tex, 1, GL_RGBA32F, level_width, level_height); - - GLuint dense_flow_fbo; - glCreateFramebuffers(1, &dense_flow_fbo); - glNamedFramebufferTexture(dense_flow_fbo, GL_COLOR_ATTACHMENT0, dense_flow_tex, 0); + GLuint uniform_width_patches, uniform_patch_size, uniform_patch_spacing; + GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex; +}; +Densify::Densify() +{ + densify_vs_obj = compile_shader(read_file("densify.vert"), GL_VERTEX_SHADER); + densify_fs_obj = compile_shader(read_file("densify.frag"), GL_FRAGMENT_SHADER); + densify_program = link_program(densify_vs_obj, densify_fs_obj); + + // Set up the VAO containing all the required position/texcoord data. + glCreateVertexArrays(1, &densify_vao); + glBindVertexArray(densify_vao); + glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + + GLint position_attrib = glGetAttribLocation(densify_program, "position"); + glEnableVertexArrayAttrib(densify_vao, position_attrib); + glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + + uniform_width_patches = glGetUniformLocation(densify_program, "width_patches"); + uniform_patch_size = glGetUniformLocation(densify_program, "patch_size"); + uniform_patch_spacing = glGetUniformLocation(densify_program, "patch_spacing"); + uniform_image0_tex = glGetUniformLocation(densify_program, "image0_tex"); + uniform_image1_tex = glGetUniformLocation(densify_program, "image1_tex"); + uniform_flow_tex = glGetUniformLocation(densify_program, "flow_tex"); +} + +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) +{ glUseProgram(densify_program); - bind_sampler(densify_program, "image0_tex", 0, tex0_view, nearest_sampler); - bind_sampler(densify_program, "image1_tex", 1, tex1_view, linear_sampler); - bind_sampler(densify_program, "flow_tex", 2, flow_out_tex, nearest_sampler); + bind_sampler(densify_program, uniform_image0_tex, 0, tex0_view, nearest_sampler); + bind_sampler(densify_program, uniform_image1_tex, 1, tex1_view, linear_sampler); + bind_sampler(densify_program, uniform_flow_tex, 2, flow_tex, nearest_sampler); - glProgramUniform1i(densify_program, glGetUniformLocation(densify_program, "width_patches"), width_patches); - glProgramUniform2f(densify_program, glGetUniformLocation(densify_program, "patch_size"), + glProgramUniform1i(densify_program, uniform_width_patches, width_patches); + glProgramUniform2f(densify_program, uniform_patch_size, float(patch_size_pixels) / level_width, float(patch_size_pixels) / level_height); float patch_spacing_x = float(level_width - patch_size_pixels) / (width_patches - 1); float patch_spacing_y = float(level_height - patch_size_pixels) / (height_patches - 1); - glProgramUniform2f(densify_program, glGetUniformLocation(densify_program, "patch_spacing"), + if (width_patches == 1) patch_spacing_x = 0.0f; // Avoid infinities. + if (height_patches == 1) patch_spacing_y = 0.0f; + glProgramUniform2f(densify_program, uniform_patch_spacing, patch_spacing_x / level_width, patch_spacing_y / level_height); + glViewport(0, 0, level_width, level_height); + glEnable(GL_BLEND); + glBlendFunc(GL_ONE, GL_ONE); + glBindVertexArray(densify_vao); + fbos.render_to(dense_flow_tex); + glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width_patches * height_patches); +} + +// Warp I_1 to I_w, and then compute the mean (I) and difference (I_t) of +// I_0 and I_w. The prewarping is what enables us to solve the variational +// flow for du,dv instead of u,v. +// +// Also calculates the normalized flow, ie. divides by z (this is needed because +// Densify works by additive blending) and multiplies by the image size. +// +// See variational_refinement.txt for more information. +class Prewarp { +public: + Prewarp(); + 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); + +private: + PersistentFBOSet<3> fbos; + + GLuint prewarp_vs_obj; + GLuint prewarp_fs_obj; + GLuint prewarp_program; + GLuint prewarp_vao; + + GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex; + GLuint uniform_image_size; +}; + +Prewarp::Prewarp() +{ + prewarp_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER); + prewarp_fs_obj = compile_shader(read_file("prewarp.frag"), GL_FRAGMENT_SHADER); + prewarp_program = link_program(prewarp_vs_obj, prewarp_fs_obj); + // Set up the VAO containing all the required position/texcoord data. - GLuint densify_vao; - glCreateVertexArrays(1, &densify_vao); - glBindVertexArray(densify_vao); + glCreateVertexArrays(1, &prewarp_vao); + glBindVertexArray(prewarp_vao); glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); - position_attrib = glGetAttribLocation(densify_program, "position"); - glEnableVertexArrayAttrib(densify_vao, position_attrib); + GLint position_attrib = glGetAttribLocation(prewarp_program, "position"); + glEnableVertexArrayAttrib(prewarp_vao, position_attrib); glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); - glBindBuffer(GL_ARRAY_BUFFER, 0); + uniform_image0_tex = glGetUniformLocation(prewarp_program, "image0_tex"); + uniform_image1_tex = glGetUniformLocation(prewarp_program, "image1_tex"); + uniform_flow_tex = glGetUniformLocation(prewarp_program, "flow_tex"); + + uniform_image_size = glGetUniformLocation(prewarp_program, "image_size"); +} + +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) +{ + glUseProgram(prewarp_program); + + bind_sampler(prewarp_program, uniform_image0_tex, 0, tex0_view, nearest_sampler); + bind_sampler(prewarp_program, uniform_image1_tex, 1, tex1_view, linear_sampler); + bind_sampler(prewarp_program, uniform_flow_tex, 2, flow_tex, nearest_sampler); + + glProgramUniform2f(prewarp_program, uniform_image_size, level_width, level_height); + + glViewport(0, 0, level_width, level_height); + glDisable(GL_BLEND); + glBindVertexArray(prewarp_vao); + fbos.render_to(I_tex, I_t_tex, normalized_flow_tex); + glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +} + +// From I, calculate the partial derivatives I_x and I_y. We use a four-tap +// central difference filter, since apparently, that's tradition (I haven't +// measured quality versus a more normal 0.5 (I[x+1] - I[x-1]).) +// The coefficients come from +// +// https://en.wikipedia.org/wiki/Finite_difference_coefficient +// +// Also computes β_0, since it depends only on I_x and I_y. +class Derivatives { +public: + Derivatives(); + void exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, int level_width, int level_height); + +private: + PersistentFBOSet<2> fbos; + + GLuint derivatives_vs_obj; + GLuint derivatives_fs_obj; + GLuint derivatives_program; + GLuint derivatives_vao; + + GLuint uniform_tex; +}; + +Derivatives::Derivatives() +{ + derivatives_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER); + derivatives_fs_obj = compile_shader(read_file("derivatives.frag"), GL_FRAGMENT_SHADER); + derivatives_program = link_program(derivatives_vs_obj, derivatives_fs_obj); + + // Set up the VAO containing all the required position/texcoord data. + glCreateVertexArrays(1, &derivatives_vao); + glBindVertexArray(derivatives_vao); + glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + + GLint position_attrib = glGetAttribLocation(derivatives_program, "position"); + glEnableVertexArrayAttrib(derivatives_vao, position_attrib); + glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + + uniform_tex = glGetUniformLocation(derivatives_program, "tex"); +} + +void Derivatives::exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, int level_width, int level_height) +{ + glUseProgram(derivatives_program); + + bind_sampler(derivatives_program, uniform_tex, 0, input_tex, nearest_sampler); + + glViewport(0, 0, level_width, level_height); + glDisable(GL_BLEND); + glBindVertexArray(derivatives_vao); + fbos.render_to(I_x_y_tex, beta_0_tex); + glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +} + +// Calculate the smoothness constraints between neighboring pixels; +// s_x(x,y) stores smoothness between pixel (x,y) and (x+1,y), +// and s_y(x,y) stores between (x,y) and (x,y+1). We'll sample with +// border color (0,0) later, so that there's zero diffusion out of +// the border. +// +// See variational_refinement.txt for more information. +class ComputeSmoothness { +public: + ComputeSmoothness(); + void exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height); + +private: + PersistentFBOSet<2> fbos; + + GLuint smoothness_vs_obj; + GLuint smoothness_fs_obj; + GLuint smoothness_program; + GLuint smoothness_vao; + + GLuint uniform_flow_tex, uniform_diff_flow_tex; + GLuint uniform_alpha; +}; + +ComputeSmoothness::ComputeSmoothness() +{ + smoothness_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER); + smoothness_fs_obj = compile_shader(read_file("smoothness.frag"), GL_FRAGMENT_SHADER); + smoothness_program = link_program(smoothness_vs_obj, smoothness_fs_obj); + + // Set up the VAO containing all the required position/texcoord data. + glCreateVertexArrays(1, &smoothness_vao); + glBindVertexArray(smoothness_vao); + glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + + GLint position_attrib = glGetAttribLocation(smoothness_program, "position"); + glEnableVertexArrayAttrib(smoothness_vao, position_attrib); + glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + + uniform_flow_tex = glGetUniformLocation(smoothness_program, "flow_tex"); + uniform_diff_flow_tex = glGetUniformLocation(smoothness_program, "diff_flow_tex"); + uniform_alpha = glGetUniformLocation(smoothness_program, "alpha"); +} + +void ComputeSmoothness::exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height) +{ + glUseProgram(smoothness_program); + + bind_sampler(smoothness_program, uniform_flow_tex, 0, flow_tex, nearest_sampler); + bind_sampler(smoothness_program, uniform_diff_flow_tex, 1, diff_flow_tex, nearest_sampler); + glProgramUniform1f(smoothness_program, uniform_alpha, vr_alpha); + + glViewport(0, 0, level_width, level_height); + + glDisable(GL_BLEND); + glBindVertexArray(smoothness_vao); + fbos.render_to(smoothness_x_tex, smoothness_y_tex); + glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); + + // Make sure the smoothness on the right and upper borders is zero. + // We could have done this by making (W-1)xH and Wx(H-1) textures instead + // (we're sampling smoothness with all-zero border color), but we'd + // have to adjust the sampling coordinates, which is annoying. + glClearTexSubImage(smoothness_x_tex, 0, level_width - 1, 0, 0, 1, level_height, 1, GL_RED, GL_FLOAT, nullptr); + glClearTexSubImage(smoothness_y_tex, 0, 0, level_height - 1, 0, level_width, 1, 1, GL_RED, GL_FLOAT, nullptr); +} + +// Set up the equations set (two equations in two unknowns, per pixel). +// We store five floats; the three non-redundant elements of the 2x2 matrix (A) +// as 32-bit floats, and the two elements on the right-hand side (b) as 16-bit +// floats. (Actually, we store the inverse of the diagonal elements, because +// we only ever need to divide by them.) This fits into four u32 values; +// R, G, B for the matrix (the last element is symmetric) and A for the two b values. +// All the values of the energy term (E_I, E_G, E_S), except the smoothness +// terms that depend on other pixels, are calculated in one pass. +// +// See variational_refinement.txt for more information. +class SetupEquations { +public: + SetupEquations(); + 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); + +private: + PersistentFBOSet<1> fbos; + + GLuint equations_vs_obj; + GLuint equations_fs_obj; + GLuint equations_program; + GLuint equations_vao; + + GLuint uniform_I_x_y_tex, uniform_I_t_tex; + GLuint uniform_diff_flow_tex, uniform_base_flow_tex; + GLuint uniform_beta_0_tex; + GLuint uniform_smoothness_x_tex, uniform_smoothness_y_tex; + GLuint uniform_gamma, uniform_delta; +}; + +SetupEquations::SetupEquations() +{ + equations_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER); + equations_fs_obj = compile_shader(read_file("equations.frag"), GL_FRAGMENT_SHADER); + equations_program = link_program(equations_vs_obj, equations_fs_obj); + + // Set up the VAO containing all the required position/texcoord data. + glCreateVertexArrays(1, &equations_vao); + glBindVertexArray(equations_vao); + glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + + GLint position_attrib = glGetAttribLocation(equations_program, "position"); + glEnableVertexArrayAttrib(equations_vao, position_attrib); + glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + + uniform_I_x_y_tex = glGetUniformLocation(equations_program, "I_x_y_tex"); + uniform_I_t_tex = glGetUniformLocation(equations_program, "I_t_tex"); + uniform_diff_flow_tex = glGetUniformLocation(equations_program, "diff_flow_tex"); + uniform_base_flow_tex = glGetUniformLocation(equations_program, "base_flow_tex"); + uniform_beta_0_tex = glGetUniformLocation(equations_program, "beta_0_tex"); + uniform_smoothness_x_tex = glGetUniformLocation(equations_program, "smoothness_x_tex"); + uniform_smoothness_y_tex = glGetUniformLocation(equations_program, "smoothness_y_tex"); + uniform_gamma = glGetUniformLocation(equations_program, "gamma"); + uniform_delta = glGetUniformLocation(equations_program, "delta"); +} + +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) +{ + glUseProgram(equations_program); + + bind_sampler(equations_program, uniform_I_x_y_tex, 0, I_x_y_tex, nearest_sampler); + bind_sampler(equations_program, uniform_I_t_tex, 1, I_t_tex, nearest_sampler); + bind_sampler(equations_program, uniform_diff_flow_tex, 2, diff_flow_tex, nearest_sampler); + bind_sampler(equations_program, uniform_base_flow_tex, 3, base_flow_tex, nearest_sampler); + bind_sampler(equations_program, uniform_beta_0_tex, 4, beta_0_tex, nearest_sampler); + bind_sampler(equations_program, uniform_smoothness_x_tex, 5, smoothness_x_tex, smoothness_sampler); + bind_sampler(equations_program, uniform_smoothness_y_tex, 6, smoothness_y_tex, smoothness_sampler); + glProgramUniform1f(equations_program, uniform_delta, vr_delta); + glProgramUniform1f(equations_program, uniform_gamma, vr_gamma); + + glViewport(0, 0, level_width, level_height); + glDisable(GL_BLEND); + glBindVertexArray(equations_vao); + fbos.render_to(equation_tex); + glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +} + +// Actually solve the equation sets made by SetupEquations, by means of +// successive over-relaxation (SOR). +// +// See variational_refinement.txt for more information. +class SOR { +public: + SOR(); + 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); + +private: + PersistentFBOSet<1> fbos; + + GLuint sor_vs_obj; + GLuint sor_fs_obj; + GLuint sor_program; + GLuint sor_vao; + + GLuint uniform_diff_flow_tex; + GLuint uniform_equation_tex; + GLuint uniform_smoothness_x_tex, uniform_smoothness_y_tex; +}; + +SOR::SOR() +{ + sor_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER); + sor_fs_obj = compile_shader(read_file("sor.frag"), GL_FRAGMENT_SHADER); + sor_program = link_program(sor_vs_obj, sor_fs_obj); + + // Set up the VAO containing all the required position/texcoord data. + glCreateVertexArrays(1, &sor_vao); + glBindVertexArray(sor_vao); + glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + + GLint position_attrib = glGetAttribLocation(sor_program, "position"); + glEnableVertexArrayAttrib(sor_vao, position_attrib); + glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + + uniform_diff_flow_tex = glGetUniformLocation(sor_program, "diff_flow_tex"); + uniform_equation_tex = glGetUniformLocation(sor_program, "equation_tex"); + uniform_smoothness_x_tex = glGetUniformLocation(sor_program, "smoothness_x_tex"); + uniform_smoothness_y_tex = glGetUniformLocation(sor_program, "smoothness_y_tex"); +} + +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) +{ + glUseProgram(sor_program); + + bind_sampler(sor_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler); + bind_sampler(sor_program, uniform_smoothness_x_tex, 1, smoothness_x_tex, smoothness_sampler); + bind_sampler(sor_program, uniform_smoothness_y_tex, 2, smoothness_y_tex, smoothness_sampler); + bind_sampler(sor_program, uniform_equation_tex, 3, equation_tex, nearest_sampler); + + glViewport(0, 0, level_width, level_height); + glDisable(GL_BLEND); + glBindVertexArray(sor_vao); + fbos.render_to(diff_flow_tex); // NOTE: Bind to same as we render from! + + for (int i = 0; i < num_iterations; ++i) { + glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); + if (i != num_iterations - 1) { + glTextureBarrier(); + } + } +} + +// Simply add the differential flow found by the variational refinement to the base flow. +// The output is in base_flow_tex; we don't need to make a new texture. +class AddBaseFlow { +public: + AddBaseFlow(); + void exec(GLuint base_flow_tex, GLuint diff_flow_tex, int level_width, int level_height); + +private: + PersistentFBOSet<1> fbos; + + GLuint add_flow_vs_obj; + GLuint add_flow_fs_obj; + GLuint add_flow_program; + GLuint add_flow_vao; + + GLuint uniform_diff_flow_tex; +}; + +AddBaseFlow::AddBaseFlow() +{ + add_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER); + add_flow_fs_obj = compile_shader(read_file("add_base_flow.frag"), GL_FRAGMENT_SHADER); + add_flow_program = link_program(add_flow_vs_obj, add_flow_fs_obj); + + // Set up the VAO containing all the required position/texcoord data. + glCreateVertexArrays(1, &add_flow_vao); + glBindVertexArray(add_flow_vao); + glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + + GLint position_attrib = glGetAttribLocation(add_flow_program, "position"); + glEnableVertexArrayAttrib(add_flow_vao, position_attrib); + glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + + uniform_diff_flow_tex = glGetUniformLocation(add_flow_program, "diff_flow_tex"); +} + +void AddBaseFlow::exec(GLuint base_flow_tex, GLuint diff_flow_tex, int level_width, int level_height) +{ + glUseProgram(add_flow_program); + + bind_sampler(add_flow_program, uniform_diff_flow_tex, 0, diff_flow_tex, nearest_sampler); - // And draw. glViewport(0, 0, level_width, level_height); glEnable(GL_BLEND); glBlendFunc(GL_ONE, GL_ONE); - glBindFramebuffer(GL_FRAMEBUFFER, dense_flow_fbo); - glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width_patches * height_patches); + glBindVertexArray(add_flow_vao); + fbos.render_to(base_flow_tex); + + glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +} + +// Take a copy of the flow, bilinearly interpolated and scaled up. +class ResizeFlow { +public: + ResizeFlow(); + void exec(GLuint in_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height); + +private: + PersistentFBOSet<1> fbos; + + GLuint resize_flow_vs_obj; + GLuint resize_flow_fs_obj; + GLuint resize_flow_program; + GLuint resize_flow_vao; + + GLuint uniform_flow_tex; + GLuint uniform_scale_factor; +}; + +ResizeFlow::ResizeFlow() +{ + resize_flow_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER); + resize_flow_fs_obj = compile_shader(read_file("resize_flow.frag"), GL_FRAGMENT_SHADER); + resize_flow_program = link_program(resize_flow_vs_obj, resize_flow_fs_obj); + + // Set up the VAO containing all the required position/texcoord data. + glCreateVertexArrays(1, &resize_flow_vao); + glBindVertexArray(resize_flow_vao); + glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + + GLint position_attrib = glGetAttribLocation(resize_flow_program, "position"); + glEnableVertexArrayAttrib(resize_flow_vao, position_attrib); + glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + + uniform_flow_tex = glGetUniformLocation(resize_flow_program, "flow_tex"); + uniform_scale_factor = glGetUniformLocation(resize_flow_program, "scale_factor"); +} + +void ResizeFlow::exec(GLuint flow_tex, GLuint out_tex, int input_width, int input_height, int output_width, int output_height) +{ + glUseProgram(resize_flow_program); + + bind_sampler(resize_flow_program, uniform_flow_tex, 0, flow_tex, nearest_sampler); + + glProgramUniform2f(resize_flow_program, uniform_scale_factor, float(output_width) / input_width, float(output_height) / input_height); + + glViewport(0, 0, output_width, output_height); + glDisable(GL_BLEND); + glBindVertexArray(resize_flow_vao); + fbos.render_to(out_tex); + + glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +} + +class GPUTimers { +public: + void print(); + pair begin_timer(const string &name, int level); + +private: + struct Timer { + string name; + int level; + pair query; + }; + vector timers; +}; + +pair GPUTimers::begin_timer(const string &name, int level) +{ + GLuint queries[2]; + glGenQueries(2, queries); + glQueryCounter(queries[0], GL_TIMESTAMP); + + Timer timer; + timer.name = name; + timer.level = level; + timer.query.first = queries[0]; + timer.query.second = queries[1]; + timers.push_back(timer); + return timer.query; +} + +void GPUTimers::print() +{ + for (const Timer &timer : timers) { + // NOTE: This makes the CPU wait for the GPU. + GLuint64 time_start, time_end; + glGetQueryObjectui64v(timer.query.first, GL_QUERY_RESULT, &time_start); + glGetQueryObjectui64v(timer.query.second, GL_QUERY_RESULT, &time_end); + //fprintf(stderr, "GPU time used = %.1f ms\n", time_elapsed / 1e6); + for (int i = 0; i < timer.level * 2; ++i) { + fprintf(stderr, " "); + } + fprintf(stderr, "%-30s %4.1f ms\n", timer.name.c_str(), GLint64(time_end - time_start) / 1e6); + } +} + +// A simple RAII class for timing until the end of the scope. +class ScopedTimer { +public: + ScopedTimer(const string &name, GPUTimers *timers) + : timers(timers), level(0) + { + query = timers->begin_timer(name, level); + } + + ScopedTimer(const string &name, ScopedTimer *parent_timer) + : timers(parent_timer->timers), + level(parent_timer->level + 1) + { + query = timers->begin_timer(name, level); + } + + ~ScopedTimer() + { + end(); + } + + void end() + { + if (!ended) { + glQueryCounter(query.second, GL_TIMESTAMP); + ended = true; + } + } + +private: + GPUTimers *timers; + int level; + pair query; + bool ended = false; +}; + +class DISComputeFlow { +public: + DISComputeFlow(int width, int height); + + // Returns a texture that must be released with release_texture() + // after use. + GLuint exec(GLuint tex0, GLuint tex1); + void release_texture(GLuint tex); + +private: + int width, height; + GLuint initial_flow_tex; + + // The various passes. + Sobel sobel; + MotionSearch motion_search; + Densify densify; + Prewarp prewarp; + Derivatives derivatives; + ComputeSmoothness compute_smoothness; + SetupEquations setup_equations; + SOR sor; + AddBaseFlow add_base_flow; + ResizeFlow resize_flow; + + struct Texture { + GLuint tex_num; + GLenum format; + GLuint width, height; + bool in_use = false; + }; + vector textures; + + GLuint get_texture(GLenum format, GLuint width, GLuint height); +}; + +DISComputeFlow::DISComputeFlow(int width, int height) + : width(width), height(height) +{ + // Make some samplers. + glCreateSamplers(1, &nearest_sampler); + glSamplerParameteri(nearest_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST); + glSamplerParameteri(nearest_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST); + glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); + glSamplerParameteri(nearest_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); + + glCreateSamplers(1, &linear_sampler); + glSamplerParameteri(linear_sampler, GL_TEXTURE_MIN_FILTER, GL_LINEAR); + glSamplerParameteri(linear_sampler, GL_TEXTURE_MAG_FILTER, GL_LINEAR); + glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); + glSamplerParameteri(linear_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); + + // The smoothness is sampled so that once we get to a smoothness involving + // a value outside the border, the diffusivity between the two becomes zero. + glCreateSamplers(1, &smoothness_sampler); + glSamplerParameteri(smoothness_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST); + glSamplerParameteri(smoothness_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST); + glSamplerParameteri(smoothness_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER); + glSamplerParameteri(smoothness_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER); + float zero[] = { 0.0f, 0.0f, 0.0f, 0.0f }; + glSamplerParameterfv(smoothness_sampler, GL_TEXTURE_BORDER_COLOR, zero); + + // Initial flow is zero, 1x1. + glCreateTextures(GL_TEXTURE_2D, 1, &initial_flow_tex); + glTextureStorage2D(initial_flow_tex, 1, GL_RG16F, 1, 1); + glClearTexImage(initial_flow_tex, 0, GL_RG, GL_FLOAT, nullptr); +} - // TODO: Variational refinement. - - unique_ptr dense_flow(new float[level_width * level_height * 3]); - glGetTextureImage(dense_flow_tex, 0, GL_RGB, GL_FLOAT, level_width * level_height * 3 * sizeof(float), dense_flow.get()); - - FILE *fp = fopen("flow.ppm", "wb"); - fprintf(fp, "P6\n%d %d\n255\n", level_width, level_height); - for (unsigned y = 0; y < level_height; ++y) { - int yy = level_height - y - 1; - for (unsigned x = 0; x < level_width; ++x) { - float du = dense_flow[(yy * level_width + x) * 3 + 0]; - float dv = dense_flow[(yy * level_width + x) * 3 + 1]; - float w = dense_flow[(yy * level_width + x) * 3 + 2]; - - du /= w; - dv /= w; - - float angle = atan2(dv * level_width, du * level_height); - float magnitude = min(hypot(du * level_width, dv * level_height) / 20.0, 1.0); - - // HSV to RGB (from Wikipedia). Saturation is 1. - float c = magnitude; - float h = (angle + M_PI) * 6.0 / (2.0 * M_PI); - float X = c * (1.0 - fabs(fmod(h, 2.0) - 1.0)); - float r = 0.0f, g = 0.0f, b = 0.0f; - if (h < 1.0f) { - r = c; g = X; - } else if (h < 2.0f) { - r = X; g = c; - } else if (h < 3.0f) { - g = c; b = X; - } else if (h < 4.0f) { - g = X; b = c; - } else if (h < 5.0f) { - r = X; b = c; - } else if (h < 6.0f) { - r = c; b = X; - } else { - // h is NaN, so black is fine. +GLuint DISComputeFlow::exec(GLuint tex0, GLuint tex1) +{ + for (const Texture &tex : textures) { + assert(!tex.in_use); + } + + int prev_level_width = 1, prev_level_height = 1; + GLuint prev_level_flow_tex = initial_flow_tex; + + GPUTimers timers; + + ScopedTimer total_timer("Total", &timers); + for (int level = coarsest_level; level >= int(finest_level); --level) { + char timer_name[256]; + snprintf(timer_name, sizeof(timer_name), "Level %d", level); + ScopedTimer level_timer(timer_name, &total_timer); + + int level_width = width >> level; + int level_height = height >> level; + float patch_spacing_pixels = patch_size_pixels * (1.0f - patch_overlap_ratio); + int width_patches = 1 + lrintf((level_width - patch_size_pixels) / patch_spacing_pixels); + int height_patches = 1 + lrintf((level_height - patch_size_pixels) / patch_spacing_pixels); + + // Make sure we always read from the correct level; the chosen + // mipmapping could otherwise be rather unpredictable, especially + // during motion search. + // TODO: create these beforehand, and stop leaking them. + GLuint tex0_view, tex1_view; + glGenTextures(1, &tex0_view); + glTextureView(tex0_view, GL_TEXTURE_2D, tex0, GL_R8, level, 1, 0, 1); + glGenTextures(1, &tex1_view); + glTextureView(tex1_view, GL_TEXTURE_2D, tex1, GL_R8, level, 1, 0, 1); + + // Create a new texture; we could be fancy and render use a multi-level + // texture, but meh. + GLuint grad0_tex = get_texture(GL_RG16F, level_width, level_height); + + // Find the derivative. + { + ScopedTimer timer("Sobel", &level_timer); + sobel.exec(tex0_view, grad0_tex, level_width, level_height); + } + + // Motion search to find the initial flow. We use the flow from the previous + // level (sampled bilinearly; no fancy tricks) as a guide, then search from there. + + // Create an output flow texture. + GLuint flow_out_tex = get_texture(GL_RGB16F, width_patches, height_patches); + + // And draw. + { + ScopedTimer timer("Motion search", &level_timer); + 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); + } + release_texture(grad0_tex); + + // Densification. + + // Set up an output texture (initially zero). + GLuint dense_flow_tex = get_texture(GL_RGB16F, level_width, level_height); + glClearTexImage(dense_flow_tex, 0, GL_RGB, GL_FLOAT, nullptr); + + // And draw. + { + ScopedTimer timer("Densification", &level_timer); + densify.exec(tex0_view, tex1_view, flow_out_tex, dense_flow_tex, level_width, level_height, width_patches, height_patches); + } + release_texture(flow_out_tex); + + // Everything below here in the loop belongs to variational refinement. + ScopedTimer varref_timer("Variational refinement", &level_timer); + + // Prewarping; create I and I_t, and a normalized base flow (so we don't + // have to normalize it over and over again, and also save some bandwidth). + // + // During the entire rest of the variational refinement, flow will be measured + // in pixels, not 0..1 normalized OpenGL texture coordinates. + // This is because variational refinement depends so heavily on derivatives, + // which are measured in intensity levels per pixel. + GLuint I_tex = get_texture(GL_R16F, level_width, level_height); + GLuint I_t_tex = get_texture(GL_R16F, level_width, level_height); + GLuint base_flow_tex = get_texture(GL_RG16F, level_width, level_height); + { + ScopedTimer timer("Prewarping", &varref_timer); + prewarp.exec(tex0_view, tex1_view, dense_flow_tex, I_tex, I_t_tex, base_flow_tex, level_width, level_height); + } + release_texture(dense_flow_tex); + + // Calculate I_x and I_y. We're only calculating first derivatives; + // the others will be taken on-the-fly in order to sample from fewer + // textures overall, since sampling from the L1 cache is cheap. + // (TODO: Verify that this is indeed faster than making separate + // double-derivative textures.) + GLuint I_x_y_tex = get_texture(GL_RG16F, level_width, level_height); + GLuint beta_0_tex = get_texture(GL_R16F, level_width, level_height); + { + ScopedTimer timer("First derivatives", &varref_timer); + derivatives.exec(I_tex, I_x_y_tex, beta_0_tex, level_width, level_height); + } + release_texture(I_tex); + + // We need somewhere to store du and dv (the flow increment, relative + // to the non-refined base flow u0 and v0). It starts at zero. + GLuint du_dv_tex = get_texture(GL_RG16F, level_width, level_height); + glClearTexImage(du_dv_tex, 0, GL_RG, GL_FLOAT, nullptr); + + // And for smoothness. + GLuint smoothness_x_tex = get_texture(GL_R16F, level_width, level_height); + GLuint smoothness_y_tex = get_texture(GL_R16F, level_width, level_height); + + // And finally for the equation set. See SetupEquations for + // the storage format. + GLuint equation_tex = get_texture(GL_RGBA32UI, level_width, level_height); + + for (int outer_idx = 0; outer_idx < level + 1; ++outer_idx) { + // Calculate the smoothness terms between the neighboring pixels, + // both in x and y direction. + { + ScopedTimer timer("Compute smoothness", &varref_timer); + compute_smoothness.exec(base_flow_tex, du_dv_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height); + } + + // Set up the 2x2 equation system for each pixel. + { + ScopedTimer timer("Set up equations", &varref_timer); + 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); + } + + // Run a few SOR (or quasi-SOR, since we're not really Jacobi) iterations. + // Note that these are to/from the same texture. + { + ScopedTimer timer("SOR", &varref_timer); + sor.exec(du_dv_tex, equation_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height, 5); } - float m = magnitude - c; - r += m; g += m; b += m; - r = max(min(r, 1.0f), 0.0f); - g = max(min(g, 1.0f), 0.0f); - b = max(min(b, 1.0f), 0.0f); - putc(lrintf(r * 255.0f), fp); - putc(lrintf(g * 255.0f), fp); - putc(lrintf(b * 255.0f), fp); + } + + release_texture(I_t_tex); + release_texture(I_x_y_tex); + release_texture(beta_0_tex); + release_texture(smoothness_x_tex); + release_texture(smoothness_y_tex); + release_texture(equation_tex); + + // Add the differential flow found by the variational refinement to the base flow, + // giving the final flow estimate for this level. + // The output is in diff_flow_tex; we don't need to make a new texture. + // You can comment out this part if you wish to test disabling of the variational refinement. + { + ScopedTimer timer("Add differential flow", &varref_timer); + add_base_flow.exec(base_flow_tex, du_dv_tex, level_width, level_height); + } + release_texture(du_dv_tex); + + if (prev_level_flow_tex != initial_flow_tex) { + release_texture(prev_level_flow_tex); + } + prev_level_flow_tex = base_flow_tex; + prev_level_width = level_width; + prev_level_height = level_height; + } + total_timer.end(); + + timers.print(); + + // Scale up the flow to the final size (if needed). + if (finest_level == 0) { + return prev_level_flow_tex; + } else { + GLuint final_tex = get_texture(GL_RG16F, width, height); + resize_flow.exec(prev_level_flow_tex, final_tex, prev_level_width, prev_level_height, width, height); + release_texture(prev_level_flow_tex); + return final_tex; + } +} + +GLuint DISComputeFlow::get_texture(GLenum format, GLuint width, GLuint height) +{ + for (Texture &tex : textures) { + if (!tex.in_use && tex.format == format && + tex.width == width && tex.height == height) { + tex.in_use = true; + return tex.tex_num; + } + } + + Texture tex; + glCreateTextures(GL_TEXTURE_2D, 1, &tex.tex_num); + glTextureStorage2D(tex.tex_num, 1, format, width, height); + tex.format = format; + tex.width = width; + tex.height = height; + tex.in_use = true; + textures.push_back(tex); + return tex.tex_num; +} + +void DISComputeFlow::release_texture(GLuint tex_num) +{ + for (Texture &tex : textures) { + if (tex.tex_num == tex_num) { + assert(tex.in_use); + tex.in_use = false; + return; + } + } + assert(false); +} + +void write_flow(const char *filename, const float *dense_flow, unsigned width, unsigned height) +{ + FILE *flowfp = fopen(filename, "wb"); + fprintf(flowfp, "FEIH"); + fwrite(&width, 4, 1, flowfp); + fwrite(&height, 4, 1, flowfp); + for (unsigned y = 0; y < height; ++y) { + int yy = height - y - 1; + for (unsigned x = 0; x < unsigned(width); ++x) { + float du = dense_flow[(yy * width + x) * 2 + 0]; + float dv = dense_flow[(yy * width + x) * 2 + 1]; + + dv = -dv; + + fwrite(&du, 4, 1, flowfp); + fwrite(&dv, 4, 1, flowfp); + } + } + fclose(flowfp); +} + +void write_ppm(const char *filename, const float *dense_flow, unsigned width, unsigned height) +{ + FILE *fp = fopen(filename, "wb"); + fprintf(fp, "P6\n%d %d\n255\n", width, height); + for (unsigned y = 0; y < unsigned(height); ++y) { + int yy = height - y - 1; + for (unsigned x = 0; x < unsigned(width); ++x) { + float du = dense_flow[(yy * width + x) * 2 + 0]; + float dv = dense_flow[(yy * width + x) * 2 + 1]; + + dv = -dv; + + uint8_t r, g, b; + flow2rgb(du, dv, &r, &g, &b); + putc(r, fp); + putc(g, fp); + putc(b, fp); } } fclose(fp); +} + +int main(int argc, char **argv) +{ + static const option long_options[] = { + { "alpha", required_argument, 0, 'a' }, + { "delta", required_argument, 0, 'd' }, + { "gamma", required_argument, 0, 'g' } + }; + + for ( ;; ) { + int option_index = 0; + int c = getopt_long(argc, argv, "a:d:g:", long_options, &option_index); + + if (c == -1) { + break; + } + switch (c) { + case 'a': + vr_alpha = atof(optarg); + break; + case 'd': + vr_delta = atof(optarg); + break; + case 'g': + vr_gamma = atof(optarg); + break; + default: + fprintf(stderr, "Unknown option '%s'\n", argv[option_index]); + exit(1); + }; + } + + if (SDL_Init(SDL_INIT_EVERYTHING) == -1) { + fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError()); + exit(1); + } + SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8); + SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0); + SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0); + SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1); + + SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE); + SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 4); + SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 5); + // SDL_GL_SetAttribute(SDL_GL_CONTEXT_FLAGS, SDL_GL_CONTEXT_DEBUG_FLAG); + SDL_Window *window = SDL_CreateWindow("OpenGL window", + SDL_WINDOWPOS_UNDEFINED, + SDL_WINDOWPOS_UNDEFINED, + 64, 64, + SDL_WINDOW_OPENGL); + SDL_GLContext context = SDL_GL_CreateContext(window); + assert(context != nullptr); + + // Load pictures. + unsigned width1, height1, width2, height2; + GLuint tex0 = load_texture(argc >= (optind + 1) ? argv[optind] : "test1499.png", &width1, &height1); + GLuint tex1 = load_texture(argc >= (optind + 2) ? argv[optind + 1] : "test1500.png", &width2, &height2); + + if (width1 != width2 || height1 != height2) { + fprintf(stderr, "Image dimensions don't match (%dx%d versus %dx%d)\n", + width1, height1, width2, height2); + exit(1); + } + + // FIXME: Should be part of DISComputeFlow (but needs to be initialized + // before all the render passes). + float vertices[] = { + 0.0f, 1.0f, + 0.0f, 0.0f, + 1.0f, 1.0f, + 1.0f, 0.0f, + }; + glCreateBuffers(1, &vertex_vbo); + glNamedBufferData(vertex_vbo, sizeof(vertices), vertices, GL_STATIC_DRAW); + glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + + DISComputeFlow compute_flow(width1, height1); + GLuint final_tex = compute_flow.exec(tex0, tex1); + + unique_ptr dense_flow(new float[width1 * height1 * 2]); + glGetTextureImage(final_tex, 0, GL_RG, GL_FLOAT, width1 * height1 * 2 * sizeof(float), dense_flow.get()); + + compute_flow.release_texture(final_tex); + + write_flow("flow.flo", dense_flow.get(), width1, height1); + write_ppm("flow.ppm", dense_flow.get(), width1, height1); fprintf(stderr, "err = %d\n", glGetError()); }