X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=flow.cpp;h=6a9d0eeb74ce551455e2392fb963e211759aaab3;hb=00bab4b054427daa31563486c3a98e0d9aa02b3f;hp=f4fbb74d67903c5ee1d422977b93636ae3026a79;hpb=804409c84346fc01270a388e099b8a99528ed0c6;p=nageru diff --git a/flow.cpp b/flow.cpp index f4fbb74..6a9d0ee 100644 --- a/flow.cpp +++ b/flow.cpp @@ -1,8 +1,5 @@ #define NO_SDL_GLEXT 1 -#define WIDTH 1280 -#define HEIGHT 720 - #include #include @@ -14,21 +11,69 @@ #include #include +#include #include +#include + +#include "util.h" #include +#include #include +#include +#include +#include #define BUFFER_OFFSET(i) ((char *)nullptr + (i)) using namespace std; +SDL_Window *window; + // 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. +// These are found through a simple grid search on some MPI-Sintel data, +// although the error (EPE) seems to be fairly insensitive to the precise values. +// Only the relative values matter, so we fix alpha (the smoothness constant) +// at unity and tweak the others. +float vr_alpha = 1.0f, vr_delta = 0.25f, vr_gamma = 0.25f; + +bool enable_timing = true; +bool enable_variational_refinement = true; // Just for debugging. +bool enable_interpolation = false; + +// Some global OpenGL objects. +// TODO: These should really be part of DISComputeFlow. +GLuint nearest_sampler, linear_sampler, zero_border_sampler; +GLuint vertex_vbo; + +// Structures for asynchronous readback. We assume everything is the same size (and GL_RG16F). +struct ReadInProgress { + GLuint pbo; + string filename0, filename1; + string flow_filename, ppm_filename; // Either may be empty for no write. +}; +stack spare_pbos; +deque reads_in_progress; + +int find_num_levels(int width, int height) +{ + int levels = 1; + for (int w = width, h = height; w > 1 || h > 1; ) { + w >>= 1; + h >>= 1; + ++levels; + } + return levels; +} + string read_file(const string &filename) { FILE *fp = fopen(filename.c_str(), "r"); @@ -107,49 +152,63 @@ GLuint compile_shader(const string &shader_src, GLenum type) return obj; } +enum MipmapPolicy { + WITHOUT_MIPMAPS, + WITH_MIPMAPS +}; -GLuint load_texture(const char *filename, unsigned width, unsigned height) +GLuint load_texture(const char *filename, unsigned *width_ret, unsigned *height_ret, MipmapPolicy mipmaps) { - 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 ourselves. + SDL_Surface *rgb_surf = SDL_ConvertSurfaceFormat(surf, SDL_PIXELFORMAT_RGBA32, /*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 * 4]); + + // 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]); + memcpy(pix.get() + y * width * 4, sptr + y2 * rgb_surf->pitch, width * 4); } + SDL_FreeSurface(rgb_surf); - int levels = 1; - for (int w = width, h = height; w > 1 || h > 1; ) { - w >>= 1; - h >>= 1; - ++levels; - } + int num_levels = (mipmaps == WITH_MIPMAPS) ? find_num_levels(width, height) : 1; GLuint tex; glCreateTextures(GL_TEXTURE_2D, 1, &tex); - glTextureStorage2D(tex, levels, GL_R8, width, height); - glTextureSubImage2D(tex, 0, 0, 0, width, height, GL_RED, GL_UNSIGNED_BYTE, pix.get()); - glGenerateTextureMipmap(tex); + glTextureStorage2D(tex, num_levels, GL_RGBA8, width, height); + glTextureSubImage2D(tex, 0, 0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, pix.get()); + + if (mipmaps == WITH_MIPMAPS) { + 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 +246,8 @@ 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; } @@ -199,190 +257,1638 @@ void bind_sampler(GLuint program, const char *uniform_name, GLuint texture_unit, glProgramUniform1i(program, location, texture_unit); } -int main(void) +// 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}}); + } + + void render_to(GLuint texture0, GLuint texture1, enable_if * = nullptr) { + render_to({{texture0, texture1}}); + } + + void render_to(GLuint texture0, GLuint texture1, GLuint texture2, enable_if * = nullptr) { + render_to({{texture0, texture1, texture2}}); + } + + void render_to(GLuint texture0, GLuint texture1, GLuint texture2, GLuint texture3, enable_if * = nullptr) { + render_to({{texture0, texture1, texture2, texture3}}); + } + +private: + // TODO: Delete these on destruction. + map, GLuint> fbos; +}; + +template +void PersistentFBOSet::render_to(const array &textures) { - if (SDL_Init(SDL_INIT_EVERYTHING) == -1) { - fprintf(stderr, "SDL_Init failed: %s\n", SDL_GetError()); - exit(1); + auto it = fbos.find(textures); + if (it != fbos.end()) { + glBindFramebuffer(GL_FRAMEBUFFER, it->second); + return; } - 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); + 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); - // Load pictures. - GLuint tex0 = load_texture("test1499.pgm", WIDTH, HEIGHT); - GLuint tex1 = load_texture("test1500.pgm", WIDTH, HEIGHT); + fbos[textures] = fbo; + glBindFramebuffer(GL_FRAMEBUFFER, fbo); +} + +// Convert RGB to grayscale, using Rec. 709 coefficients. +class GrayscaleConversion { +public: + GrayscaleConversion(); + void exec(GLint tex, GLint gray_tex, int width, int height); + +private: + PersistentFBOSet<1> fbos; + GLuint gray_vs_obj; + GLuint gray_fs_obj; + GLuint gray_program; + GLuint gray_vao; + + GLuint uniform_tex; +}; + +GrayscaleConversion::GrayscaleConversion() +{ + gray_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER); + gray_fs_obj = compile_shader(read_file("gray.frag"), GL_FRAGMENT_SHADER); + gray_program = link_program(gray_vs_obj, gray_fs_obj); + + // Set up the VAO containing all the required position/texcoord data. + glCreateVertexArrays(1, &gray_vao); + glBindVertexArray(gray_vao); + + GLint position_attrib = glGetAttribLocation(gray_program, "position"); + glEnableVertexArrayAttrib(gray_vao, position_attrib); + glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + + uniform_tex = glGetUniformLocation(gray_program, "tex"); +} + +void GrayscaleConversion::exec(GLint tex, GLint gray_tex, int width, int height) +{ + glUseProgram(gray_program); + bind_sampler(gray_program, uniform_tex, 0, tex, nearest_sampler); + + glViewport(0, 0, width, height); + fbos.render_to(gray_tex); + glBindVertexArray(gray_vao); + glUseProgram(gray_program); + glDisable(GL_BLEND); + glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +} + +// 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; + + GLuint uniform_tex; +}; + +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. + glCreateVertexArrays(1, &sobel_vao); + glBindVertexArray(sobel_vao); + + GLint position_attrib = glGetAttribLocation(sobel_program, "position"); + glEnableVertexArrayAttrib(sobel_vao, position_attrib); + glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + + uniform_tex = glGetUniformLocation(sobel_program, "tex"); +} + +void Sobel::exec(GLint tex0_view, GLint grad0_tex, int level_width, int level_height) +{ + glUseProgram(sobel_program); + bind_sampler(sobel_program, uniform_tex, 0, tex0_view, nearest_sampler); + + glViewport(0, 0, level_width, level_height); + 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. 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); + +private: + PersistentFBOSet<1> fbos; + + GLuint motion_vs_obj; + GLuint motion_fs_obj; + GLuint motion_search_program; + GLuint motion_search_vao; + + GLuint uniform_inv_image_size, uniform_inv_prev_level_size; + GLuint uniform_image0_tex, uniform_image1_tex, uniform_grad0_tex, uniform_flow_tex; +}; + +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. + glCreateVertexArrays(1, &motion_search_vao); + glBindVertexArray(motion_search_vao); + glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + + 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)); + + 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"); +} + +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, zero_border_sampler); + bind_sampler(motion_search_program, uniform_flow_tex, 3, flow_tex, linear_sampler); + + 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); + + glViewport(0, 0, width_patches, height_patches); + 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; + + GLuint 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_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, 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); + + 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); + 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; +}; + +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. + glCreateVertexArrays(1, &prewarp_vao); + glBindVertexArray(prewarp_vao); + glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + + GLint position_attrib = glGetAttribLocation(prewarp_program, "position"); + glEnableVertexArrayAttrib(prewarp_vao, position_attrib); + glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(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"); +} + +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); + + 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, zero_border_sampler); + bind_sampler(equations_program, uniform_smoothness_y_tex, 6, smoothness_y_tex, zero_border_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; + GLuint uniform_phase; +}; + +SOR::SOR() +{ + sor_vs_obj = compile_shader(read_file("sor.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"); + uniform_phase = glGetUniformLocation(sor_program, "phase"); +} + +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, zero_border_sampler); + bind_sampler(sor_program, uniform_smoothness_y_tex, 2, smoothness_y_tex, zero_border_sampler); + bind_sampler(sor_program, uniform_equation_tex, 3, equation_tex, nearest_sampler); + + // NOTE: We bind to the texture we are rendering from, but we never write any value + // that we read in the same shader pass (we call discard for red values when we compute + // black, and vice versa), and we have barriers between the passes, so we're fine + // as per the spec. + glViewport(0, 0, level_width, level_height); + glDisable(GL_BLEND); + glBindVertexArray(sor_vao); + fbos.render_to(diff_flow_tex); + + for (int i = 0; i < num_iterations; ++i) { + glProgramUniform1i(sor_program, uniform_phase, 0); + glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); + glTextureBarrier(); + glProgramUniform1i(sor_program, uniform_phase, 1); + 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); + + glViewport(0, 0, level_width, level_height); + glEnable(GL_BLEND); + glBlendFunc(GL_ONE, GL_ONE); + glBindVertexArray(add_flow_vao); + fbos.render_to(base_flow_tex); + + glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +} - // 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); +// 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); - 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: + 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) +{ + if (!enable_timing) { + return make_pair(0, 0); + } + + 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 (enable_timing && !ended) { + glQueryCounter(query.second, GL_TIMESTAMP); + ended = true; + } + } + +private: + GPUTimers *timers; + int level; + pair query; + bool ended = false; +}; + +class TexturePool { +public: + GLuint get_texture(GLenum format, GLuint width, GLuint height); + void release_texture(GLuint tex_num); + +private: + struct Texture { + GLuint tex_num; + GLenum format; + GLuint width, height; + bool in_use = false; + }; + vector textures; +}; + +class DISComputeFlow { +public: + DISComputeFlow(int width, int height); + + enum ResizeStrategy { + DO_NOT_RESIZE_FLOW, + RESIZE_FLOW_TO_FULL_SIZE + }; + + // Returns a texture that must be released with release_texture() + // after use. + GLuint exec(GLuint tex0, GLuint tex1, ResizeStrategy resize_strategy); + + void release_texture(GLuint tex) { + pool.release_texture(tex); + } + +private: + int width, height; + GLuint initial_flow_tex; + TexturePool pool; + + // 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; +}; + +DISComputeFlow::DISComputeFlow(int width, int height) + : width(width), height(height) +{ // 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 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); - 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); + // 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. + // Similarly, gradients are zero outside the border, since the edge is taken + // to be constant. + glCreateSamplers(1, &zero_border_sampler); + glSamplerParameteri(zero_border_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST); + glSamplerParameteri(zero_border_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST); + glSamplerParameteri(zero_border_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER); + glSamplerParameteri(zero_border_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER); + float zero[] = { 0.0f, 0.0f, 0.0f, 0.0f }; + glSamplerParameterfv(zero_border_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); +} - 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 DISComputeFlow::exec(GLuint tex0, GLuint tex1, ResizeStrategy resize_strategy) +{ + 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); + + // Make sure we have patches at least every Nth pixel, e.g. for width=9 + // and patch_spacing=3 (the default), we put out patch centers in + // x=0, x=3, x=6, x=9, which is four patches. The fragment shader will + // lock all the centers to integer coordinates if needed. + int width_patches = 1 + ceil(level_width / patch_spacing_pixels); + int height_patches = 1 + ceil(level_height / 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); + + // Create a new texture; we could be fancy and render use a multi-level + // texture, but meh. + GLuint grad0_tex = pool.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 = pool.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); + } + pool.release_texture(grad0_tex); + + // Densification. + + // Set up an output texture (initially zero). + GLuint dense_flow_tex = pool.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); + } + pool.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 = pool.get_texture(GL_R16F, level_width, level_height); + GLuint I_t_tex = pool.get_texture(GL_R16F, level_width, level_height); + GLuint base_flow_tex = pool.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); + } + pool.release_texture(dense_flow_tex); + glDeleteTextures(1, &tex0_view); + glDeleteTextures(1, &tex1_view); + + // 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 = pool.get_texture(GL_RG16F, level_width, level_height); + GLuint beta_0_tex = pool.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); + } + pool.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 = pool.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 = pool.get_texture(GL_R16F, level_width, level_height); + GLuint smoothness_y_tex = pool.get_texture(GL_R16F, level_width, level_height); + + // And finally for the equation set. See SetupEquations for + // the storage format. + GLuint equation_tex = pool.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); + } + } + + pool.release_texture(I_t_tex); + pool.release_texture(I_x_y_tex); + pool.release_texture(beta_0_tex); + pool.release_texture(smoothness_x_tex); + pool.release_texture(smoothness_y_tex); + pool.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. + // + // Disabling this doesn't save any time (although we could easily make it so that + // it is more efficient), but it helps debug the motion search. + if (enable_variational_refinement) { + ScopedTimer timer("Add differential flow", &varref_timer); + add_base_flow.exec(base_flow_tex, du_dv_tex, level_width, level_height); + } + pool.release_texture(du_dv_tex); + + if (prev_level_flow_tex != initial_flow_tex) { + pool.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 || resize_strategy == DO_NOT_RESIZE_FLOW) { + return prev_level_flow_tex; + } else { + GLuint final_tex = pool.get_texture(GL_RG16F, width, height); + resize_flow.exec(prev_level_flow_tex, final_tex, prev_level_width, prev_level_height, width, height); + pool.release_texture(prev_level_flow_tex); + return final_tex; + } +} + +// Forward-warp the flow half-way (or rather, by alpha). A non-zero “splatting” +// radius fills most of the holes. +class Splat { +public: + Splat(); + + // alpha is the time of the interpolated frame (0..1). + void exec(GLuint tex0, GLuint tex1, GLuint forward_flow_tex, GLuint backward_flow_tex, GLuint flow_tex, GLuint depth_tex, int width, int height, float alpha); + +private: + PersistentFBOSet<2> fbos; + + GLuint splat_vs_obj; + GLuint splat_fs_obj; + GLuint splat_program; + GLuint splat_vao; + + GLuint uniform_invert_flow, uniform_splat_size, uniform_alpha; + GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex; + GLuint uniform_inv_flow_size; +}; + +Splat::Splat() +{ + splat_vs_obj = compile_shader(read_file("splat.vert"), GL_VERTEX_SHADER); + splat_fs_obj = compile_shader(read_file("splat.frag"), GL_FRAGMENT_SHADER); + splat_program = link_program(splat_vs_obj, splat_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); + glCreateVertexArrays(1, &splat_vao); + glBindVertexArray(splat_vao); glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); - int position_attrib = glGetAttribLocation(sobel_program, "position"); - glEnableVertexArrayAttrib(sobel_vao, position_attrib); + GLint position_attrib = glGetAttribLocation(splat_program, "position"); + glEnableVertexArrayAttrib(splat_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_invert_flow = glGetUniformLocation(splat_program, "invert_flow"); + uniform_splat_size = glGetUniformLocation(splat_program, "splat_size"); + uniform_alpha = glGetUniformLocation(splat_program, "alpha"); + uniform_image0_tex = glGetUniformLocation(splat_program, "image0_tex"); + uniform_image1_tex = glGetUniformLocation(splat_program, "image1_tex"); + uniform_flow_tex = glGetUniformLocation(splat_program, "flow_tex"); + uniform_inv_flow_size = glGetUniformLocation(splat_program, "inv_flow_size"); +} - glBindBuffer(GL_ARRAY_BUFFER, 0); +void Splat::exec(GLuint tex0, GLuint tex1, GLuint forward_flow_tex, GLuint backward_flow_tex, GLuint flow_tex, GLuint depth_tex, int width, int height, float alpha) +{ + glUseProgram(splat_program); + + bind_sampler(splat_program, uniform_image0_tex, 0, tex0, linear_sampler); + bind_sampler(splat_program, uniform_image1_tex, 1, tex1, linear_sampler); + + // FIXME: This is set to 1.0 right now so not to trigger Haswell's “PMA stall”. + // Move to 2.0 later. + float splat_size = 1.0f; // 4x4 splat means 16x overdraw, 2x2 splat means 4x overdraw. + glProgramUniform2f(splat_program, uniform_splat_size, splat_size / width, splat_size / height); + glProgramUniform1f(splat_program, uniform_alpha, alpha); + glProgramUniform2f(splat_program, uniform_inv_flow_size, 1.0f / width, 1.0f / height); + + glViewport(0, 0, width, height); + glDisable(GL_BLEND); + glEnable(GL_DEPTH_TEST); + glDepthFunc(GL_LESS); // We store the difference between I_0 and I_1, where less difference is good. (Default 1.0 is effectively +inf, which always loses.) + glBindVertexArray(splat_vao); + + // FIXME: Get this into FBOSet, so we can reuse FBOs across frames. + GLuint fbo; + glCreateFramebuffers(1, &fbo); + glNamedFramebufferTexture(fbo, GL_COLOR_ATTACHMENT0, flow_tex, 0); + glNamedFramebufferTexture(fbo, GL_DEPTH_ATTACHMENT, depth_tex, 0); + glBindFramebuffer(GL_FRAMEBUFFER, fbo); + + // Do forward splatting. + bind_sampler(splat_program, uniform_flow_tex, 2, forward_flow_tex, nearest_sampler); + glProgramUniform1i(splat_program, uniform_invert_flow, 0); + glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width * height); + + // Do backward splatting. + bind_sampler(splat_program, uniform_flow_tex, 2, backward_flow_tex, nearest_sampler); + glProgramUniform1i(splat_program, uniform_invert_flow, 1); + glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width * height); + + glDisable(GL_DEPTH_TEST); + + glDeleteFramebuffers(1, &fbo); +} + +class Blend { +public: + Blend(); + void exec(GLuint tex0, GLuint tex1, GLuint flow_tex, GLuint output_tex, int width, int height, float alpha); + +private: + PersistentFBOSet<1> fbos; + GLuint blend_vs_obj; + GLuint blend_fs_obj; + GLuint blend_program; + GLuint blend_vao; + + GLuint uniform_image0_tex, uniform_image1_tex, uniform_flow_tex; + GLuint uniform_alpha, uniform_flow_consistency_tolerance; +}; + +Blend::Blend() +{ + blend_vs_obj = compile_shader(read_file("vs.vert"), GL_VERTEX_SHADER); + blend_fs_obj = compile_shader(read_file("blend.frag"), GL_FRAGMENT_SHADER); + blend_program = link_program(blend_vs_obj, blend_fs_obj); + + // Set up the VAO containing all the required position/texcoord data. + glCreateVertexArrays(1, &blend_vao); + glBindVertexArray(blend_vao); + + GLint position_attrib = glGetAttribLocation(blend_program, "position"); + glEnableVertexArrayAttrib(blend_vao, position_attrib); + glVertexAttribPointer(position_attrib, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0)); + + uniform_image0_tex = glGetUniformLocation(blend_program, "image0_tex"); + uniform_image1_tex = glGetUniformLocation(blend_program, "image1_tex"); + uniform_flow_tex = glGetUniformLocation(blend_program, "flow_tex"); + uniform_alpha = glGetUniformLocation(blend_program, "alpha"); + uniform_flow_consistency_tolerance = glGetUniformLocation(blend_program, "flow_consistency_tolerance"); +} + +void Blend::exec(GLuint tex0, GLuint tex1, GLuint flow_tex, GLuint output_tex, int level_width, int level_height, float alpha) +{ + glUseProgram(blend_program); + bind_sampler(blend_program, uniform_image0_tex, 0, tex0, linear_sampler); + bind_sampler(blend_program, uniform_image1_tex, 1, tex1, linear_sampler); + bind_sampler(blend_program, uniform_flow_tex, 2, flow_tex, linear_sampler); // May be upsampled. + glProgramUniform1f(blend_program, uniform_alpha, alpha); + //glProgramUniform1f(blend_program, uniform_flow_consistency_tolerance, 1.0f / - // Now finally draw. glViewport(0, 0, level_width, level_height); - glBindFramebuffer(GL_FRAMEBUFFER, grad0_fbo); - glUseProgram(sobel_program); + fbos.render_to(output_tex); + glBindVertexArray(blend_vao); + glUseProgram(blend_program); + glDisable(GL_BLEND); // A bit ironic, perhaps. glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +} - // Motion search to find the initial flow. +class Interpolate { +public: + Interpolate(int width, int height, int flow_level); - // 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); + // Returns a texture that must be released with release_texture() + // after use. tex0 and tex1 must be RGBA8 textures with mipmaps + // (unless flow_level == 0). + GLuint exec(GLuint tex0, GLuint tex1, GLuint forward_flow_tex, GLuint backward_flow_tex, GLuint width, GLuint height, float alpha); - // 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); + void release_texture(GLuint tex) { + pool.release_texture(tex); + } - GLuint flow_fbo; - glCreateFramebuffers(1, &flow_fbo); - glNamedFramebufferTexture(flow_fbo, GL_COLOR_ATTACHMENT0, flow_out_tex, 0); +private: + int width, height, flow_level; + TexturePool pool; + Splat splat; + Blend blend; +}; - glUseProgram(motion_search_program); +Interpolate::Interpolate(int width, int height, int flow_level) + : width(width), height(height), flow_level(flow_level) {} - 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 Interpolate::exec(GLuint tex0, GLuint tex1, GLuint forward_flow_tex, GLuint backward_flow_tex, GLuint width, GLuint height, float alpha) +{ + GPUTimers timers; - 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); + ScopedTimer total_timer("Total", &timers); -// printf("%d x %d patches on this level\n", width_patches, height_patches); + // Pick out the right level to test splatting results on. + GLuint tex0_view, tex1_view; + glGenTextures(1, &tex0_view); + glTextureView(tex0_view, GL_TEXTURE_2D, tex0, GL_RGBA8, flow_level, 1, 0, 1); + glGenTextures(1, &tex1_view); + glTextureView(tex1_view, GL_TEXTURE_2D, tex1, GL_RGBA8, flow_level, 1, 0, 1); + + int flow_width = width >> flow_level; + int flow_height = height >> flow_level; + + GLuint flow_tex = pool.get_texture(GL_RG16F, flow_width, flow_height); + GLuint depth_tex = pool.get_texture(GL_DEPTH_COMPONENT32F, flow_width, flow_height); // Used for ranking flows. + { + ScopedTimer timer("Clear", &total_timer); + glClearTexImage(flow_tex, 0, GL_RG, GL_FLOAT, nullptr); + float infinity = 1.0f; + glClearTexImage(depth_tex, 0, GL_DEPTH_COMPONENT, GL_FLOAT, &infinity); + } - // Set up the VAO containing all the required position/texcoord data. - GLuint motion_search_vao; - glCreateVertexArrays(1, &motion_search_vao); - glBindVertexArray(motion_search_vao); - glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo); + //SDL_GL_SwapWindow(window); + { + ScopedTimer timer("Splat", &total_timer); + splat.exec(tex0_view, tex1_view, forward_flow_tex, backward_flow_tex, flow_tex, depth_tex, flow_width, flow_height, alpha); + } + //SDL_GL_SwapWindow(window); + pool.release_texture(depth_tex); + glDeleteTextures(1, &tex0_view); + glDeleteTextures(1, &tex1_view); + + GLuint output_tex = pool.get_texture(GL_RGB8, width, height); + { + ScopedTimer timer("Blend", &total_timer); + blend.exec(tex0, tex1, flow_tex, output_tex, width, height, alpha); + } + total_timer.end(); + timers.print(); - 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)); + return output_tex; +} - 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)); +GLuint TexturePool::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; + } + } - glBindBuffer(GL_ARRAY_BUFFER, 0); + 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; +} - // And draw. - glViewport(0, 0, width_patches, height_patches); - glBindFramebuffer(GL_FRAMEBUFFER, flow_fbo); - glUseProgram(motion_search_program); - glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +void TexturePool::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); +} + +// OpenGL uses a bottom-left coordinate system, .flo files use a top-left coordinate system. +void flip_coordinate_system(float *dense_flow, unsigned width, unsigned height) +{ + for (unsigned i = 0; i < width * height; ++i) { + dense_flow[i * 2 + 1] = -dense_flow[i * 2 + 1]; + } +} + +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; + fwrite(&dense_flow[yy * width * 2], width * 2 * sizeof(float), 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]; + + uint8_t r, g, b; + flow2rgb(du, dv, &r, &g, &b); + putc(r, fp); + putc(g, fp); + putc(b, fp); + } + } + fclose(fp); +} + +void finish_one_read(GLuint width, GLuint height) +{ + assert(!reads_in_progress.empty()); + ReadInProgress read = reads_in_progress.front(); + reads_in_progress.pop_front(); + + unique_ptr flow(new float[width * height * 2]); + void *buf = glMapNamedBufferRange(read.pbo, 0, width * height * 2 * sizeof(float), GL_MAP_READ_BIT); // Blocks if the read isn't done yet. + memcpy(flow.get(), buf, width * height * 2 * sizeof(float)); + glUnmapNamedBuffer(read.pbo); + spare_pbos.push(read.pbo); + + flip_coordinate_system(flow.get(), width, height); + if (!read.flow_filename.empty()) { + write_flow(read.flow_filename.c_str(), flow.get(), width, height); + fprintf(stderr, "%s %s -> %s\n", read.filename0.c_str(), read.filename1.c_str(), read.flow_filename.c_str()); + } + if (!read.ppm_filename.empty()) { + write_ppm(read.ppm_filename.c_str(), flow.get(), width, height); + } +} + +void schedule_read(GLuint tex, GLuint width, GLuint height, const char *filename0, const char *filename1, const char *flow_filename, const char *ppm_filename) +{ + if (spare_pbos.empty()) { + finish_one_read(width, height); + } + assert(!spare_pbos.empty()); + reads_in_progress.emplace_back(ReadInProgress{ spare_pbos.top(), filename0, filename1, flow_filename, ppm_filename }); + glBindBuffer(GL_PIXEL_PACK_BUFFER, spare_pbos.top()); + spare_pbos.pop(); + glGetTextureImage(tex, 0, GL_RG, GL_FLOAT, width * height * 2 * sizeof(float), nullptr); + glBindBuffer(GL_PIXEL_PACK_BUFFER, 0); +} + +void compute_flow_only(int argc, char **argv, int optind) +{ + const char *filename0 = argc >= (optind + 1) ? argv[optind] : "test1499.png"; + const char *filename1 = argc >= (optind + 2) ? argv[optind + 1] : "test1500.png"; + const char *flow_filename = argc >= (optind + 3) ? argv[optind + 2] : "flow.flo"; + + // Load pictures. + unsigned width1, height1, width2, height2; + GLuint tex0 = load_texture(filename0, &width1, &height1, WITHOUT_MIPMAPS); + GLuint tex1 = load_texture(filename1, &width2, &height2, WITHOUT_MIPMAPS); + + if (width1 != width2 || height1 != height2) { + fprintf(stderr, "Image dimensions don't match (%dx%d versus %dx%d)\n", + width1, height1, width2, height2); + exit(1); + } + + // Set up some PBOs to do asynchronous readback. + GLuint pbos[5]; + glCreateBuffers(5, pbos); + for (int i = 0; i < 5; ++i) { + glNamedBufferData(pbos[i], width1 * height1 * 2 * sizeof(float), nullptr, GL_STREAM_READ); + spare_pbos.push(pbos[i]); + } + + int levels = find_num_levels(width1, height1); + GLuint tex0_gray, tex1_gray; + glCreateTextures(GL_TEXTURE_2D, 1, &tex0_gray); + glCreateTextures(GL_TEXTURE_2D, 1, &tex1_gray); + glTextureStorage2D(tex0_gray, levels, GL_R8, width1, height1); + glTextureStorage2D(tex1_gray, levels, GL_R8, width1, height1); + + GrayscaleConversion gray; + gray.exec(tex0, tex0_gray, width1, height1); + glDeleteTextures(1, &tex0); + glGenerateTextureMipmap(tex0_gray); + + gray.exec(tex1, tex1_gray, width1, height1); + glDeleteTextures(1, &tex1); + glGenerateTextureMipmap(tex1_gray); + + DISComputeFlow compute_flow(width1, height1); + GLuint final_tex = compute_flow.exec(tex0_gray, tex1_gray, DISComputeFlow::RESIZE_FLOW_TO_FULL_SIZE); + + schedule_read(final_tex, width1, height1, filename0, filename1, flow_filename, "flow.ppm"); + compute_flow.release_texture(final_tex); + + // See if there are more flows on the command line (ie., more than three arguments), + // and if so, process them. + int num_flows = (argc - optind) / 3; + for (int i = 1; i < num_flows; ++i) { + const char *filename0 = argv[optind + i * 3 + 0]; + const char *filename1 = argv[optind + i * 3 + 1]; + const char *flow_filename = argv[optind + i * 3 + 2]; + GLuint width, height; + GLuint tex0 = load_texture(filename0, &width, &height, WITHOUT_MIPMAPS); + if (width != width1 || height != height1) { + fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n", + filename0, width, height, width1, height1); + exit(1); + } + gray.exec(tex0, tex0_gray, width, height); + glGenerateTextureMipmap(tex0_gray); + glDeleteTextures(1, &tex0); + + GLuint tex1 = load_texture(filename1, &width, &height, WITHOUT_MIPMAPS); + if (width != width1 || height != height1) { + fprintf(stderr, "%s: Image dimensions don't match (%dx%d versus %dx%d)\n", + filename1, width, height, width1, height1); + exit(1); + } + gray.exec(tex1, tex1_gray, width, height); + glGenerateTextureMipmap(tex1_gray); + glDeleteTextures(1, &tex1); + + GLuint final_tex = compute_flow.exec(tex0_gray, tex1_gray, DISComputeFlow::RESIZE_FLOW_TO_FULL_SIZE); + + schedule_read(final_tex, width1, height1, filename0, filename1, flow_filename, ""); + compute_flow.release_texture(final_tex); + } + glDeleteTextures(1, &tex0_gray); + glDeleteTextures(1, &tex1_gray); + + while (!reads_in_progress.empty()) { + finish_one_read(width1, height1); + } +} + +// Interpolate images based on +// +// Herbst, Seitz, Baker: “Occlusion Reasoning for Temporal Interpolation +// Using Optical Flow” +// +// or at least a reasonable subset thereof. Unfinished. +void interpolate_image(int argc, char **argv, int optind) +{ + const char *filename0 = argc >= (optind + 1) ? argv[optind] : "test1499.png"; + const char *filename1 = argc >= (optind + 2) ? argv[optind + 1] : "test1500.png"; + //const char *out_filename = argc >= (optind + 3) ? argv[optind + 2] : "interpolated.png"; + + // Load pictures. + unsigned width1, height1, width2, height2; + GLuint tex0 = load_texture(filename0, &width1, &height1, WITH_MIPMAPS); + GLuint tex1 = load_texture(filename1, &width2, &height2, WITH_MIPMAPS); + + if (width1 != width2 || height1 != height2) { + fprintf(stderr, "Image dimensions don't match (%dx%d versus %dx%d)\n", + width1, height1, width2, height2); + exit(1); + } + + // Set up some PBOs to do asynchronous readback. + GLuint pbos[5]; + glCreateBuffers(5, pbos); + for (int i = 0; i < 5; ++i) { + glNamedBufferData(pbos[i], width1 * height1 * 2 * sizeof(float), nullptr, GL_STREAM_READ); + spare_pbos.push(pbos[i]); + } + + DISComputeFlow compute_flow(width1, height1); + GrayscaleConversion gray; + Interpolate interpolate(width1, height1, finest_level); + //Interpolate interpolate(width1, height1, 0); + + int levels = find_num_levels(width1, height1); + GLuint tex0_gray, tex1_gray; + glCreateTextures(GL_TEXTURE_2D, 1, &tex0_gray); + glCreateTextures(GL_TEXTURE_2D, 1, &tex1_gray); + glTextureStorage2D(tex0_gray, levels, GL_R8, width1, height1); + glTextureStorage2D(tex1_gray, levels, GL_R8, width1, height1); + + gray.exec(tex0, tex0_gray, width1, height1); + glGenerateTextureMipmap(tex0_gray); + + gray.exec(tex1, tex1_gray, width1, height1); + glGenerateTextureMipmap(tex1_gray); + + GLuint forward_flow_tex = compute_flow.exec(tex0_gray, tex1_gray, DISComputeFlow::DO_NOT_RESIZE_FLOW); + GLuint backward_flow_tex = compute_flow.exec(tex1_gray, tex0_gray, DISComputeFlow::DO_NOT_RESIZE_FLOW); + + for (int frameno = 1; frameno < 60; ++frameno) { + float alpha = frameno / 60.0f; + GLuint interpolated_tex = interpolate.exec(tex0, tex1, forward_flow_tex, backward_flow_tex, width1, height1, alpha); + + unique_ptr rgb(new uint8_t[width1 * height1 * 3]); + glGetTextureImage(interpolated_tex, 0, GL_RGB, GL_UNSIGNED_BYTE, width1 * height1 * 3, rgb.get()); + + char buf[256]; + snprintf(buf, sizeof(buf), "interp%04d.ppm", frameno); + FILE *fp = fopen(buf, "wb"); + fprintf(fp, "P6\n%d %d\n255\n", width1, height1); + for (unsigned y = 0; y < height1; ++y) { + unsigned y2 = height1 - 1 - y; + fwrite(rgb.get() + y2 * width1 * 3, width1 * 3, 1, fp); + } + fclose(fp); + } + + //schedule_read(interpolated_tex, width1, height1, filename0, filename1, "", "halfflow.ppm"); + //interpolate.release_texture(interpolated_tex); + //finish_one_read(width1, height1); +} + +int main(int argc, char **argv) +{ + static const option long_options[] = { + { "smoothness-relative-weight", required_argument, 0, 's' }, // alpha. + { "intensity-relative-weight", required_argument, 0, 'i' }, // delta. + { "gradient-relative-weight", required_argument, 0, 'g' }, // gamma. + { "disable-timing", no_argument, 0, 1000 }, + { "ignore-variational-refinement", no_argument, 0, 1001 }, // Still calculates it, just doesn't apply it. + { "interpolate", no_argument, 0, 1002 } + }; + + for ( ;; ) { + int option_index = 0; + int c = getopt_long(argc, argv, "s:i:g:", long_options, &option_index); + + if (c == -1) { + break; + } + switch (c) { + case 's': + vr_alpha = atof(optarg); + break; + case 'i': + vr_delta = atof(optarg); + break; + case 'g': + vr_gamma = atof(optarg); + break; + case 1000: + enable_timing = false; + break; + case 1001: + enable_variational_refinement = false; + break; + case 1002: + enable_interpolation = true; + break; + default: + fprintf(stderr, "Unknown option '%s'\n", argv[option_index]); + exit(1); + }; + } - fprintf(stderr, "err = %d\n", glGetError()); + 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); + window = SDL_CreateWindow("OpenGL window", + SDL_WINDOWPOS_UNDEFINED, + SDL_WINDOWPOS_UNDEFINED, + 64, 64, + SDL_WINDOW_OPENGL | SDL_WINDOW_HIDDEN); + SDL_GLContext context = SDL_GL_CreateContext(window); + assert(context != nullptr); + + // 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); + + if (enable_interpolation) { + interpolate_image(argc, argv, optind); + } else { + compute_flow_only(argc, argv, optind); + } }