X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=flow.cpp;h=9bae425004d359345b9ee84f827055e4443cbcd9;hb=24c21cf229d7e273ecc0e7ad0dc93bcb9fe466e3;hp=3100c50a601c6c5fa6259785c6ee68d4ff667721;hpb=7fd9c180ab8e99c8bc542e347a99ca565f393742;p=nageru diff --git a/flow.cpp b/flow.cpp index 3100c50..9bae425 100644 --- a/flow.cpp +++ b/flow.cpp @@ -1,5 +1,5 @@ #define NO_SDL_GLEXT 1 - + #define WIDTH 1280 #define HEIGHT 720 @@ -15,6 +15,9 @@ #include #include +#include + +#include "util.h" #include #include @@ -25,10 +28,14 @@ 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; +// Some global OpenGL objects. +GLuint nearest_sampler, linear_sampler; +GLuint vertex_vbo; + string read_file(const string &filename) { FILE *fp = fopen(filename.c_str(), "r"); @@ -185,7 +192,331 @@ GLuint fill_vertex_attribute(GLuint vao, GLuint glsl_program_num, const string & glBindBuffer(GL_ARRAY_BUFFER, 0); return vbo; -} +} + +void bind_sampler(GLuint program, GLint location, GLuint texture_unit, GLuint tex, GLuint sampler) +{ + if (location == -1) { + return; + } + + glBindTextureUnit(texture_unit, tex); + glBindSampler(texture_unit, sampler); + glProgramUniform1i(program, location, texture_unit); +} + +// 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: + GLuint sobel_vs_obj; + GLuint sobel_fs_obj; + GLuint sobel_program; + GLuint sobel_vao; + + 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. + 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); + glBindTextureUnit(0, tex0_view); + glBindSampler(0, nearest_sampler); + glProgramUniform1i(sobel_program, uniform_tex, 0); + + GLuint grad0_fbo; // TODO: cleanup + glCreateFramebuffers(1, &grad0_fbo); + glNamedFramebufferTexture(grad0_fbo, GL_COLOR_ATTACHMENT0, grad0_tex, 0); + + glViewport(0, 0, level_width, level_height); + glBindFramebuffer(GL_FRAMEBUFFER, grad0_fbo); + 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 width_patches, int height_patches); + +private: + GLuint motion_vs_obj; + GLuint motion_fs_obj; + GLuint motion_search_program; + GLuint motion_search_vao; + + GLuint uniform_image_size, uniform_inv_image_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_image_size = glGetUniformLocation(motion_search_program, "image_size"); + uniform_inv_image_size = glGetUniformLocation(motion_search_program, "inv_image_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 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); + + GLuint flow_fbo; // TODO: cleanup + glCreateFramebuffers(1, &flow_fbo); + glNamedFramebufferTexture(flow_fbo, GL_COLOR_ATTACHMENT0, flow_out_tex, 0); + + glViewport(0, 0, width_patches, height_patches); + glBindFramebuffer(GL_FRAMEBUFFER, flow_fbo); + 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: + GLuint densify_vs_obj; + GLuint densify_fs_obj; + GLuint densify_program; + GLuint densify_vao; + + 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, 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, 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, uniform_patch_spacing, + patch_spacing_x / level_width, + patch_spacing_y / level_height); + + GLuint dense_flow_fbo; // TODO: cleanup + glCreateFramebuffers(1, &dense_flow_fbo); + glNamedFramebufferTexture(dense_flow_fbo, GL_COLOR_ATTACHMENT0, dense_flow_tex, 0); + + glViewport(0, 0, level_width, level_height); + glEnable(GL_BLEND); + glBlendFunc(GL_ONE, GL_ONE); + glBindVertexArray(densify_vao); + glBindFramebuffer(GL_FRAMEBUFFER, dense_flow_fbo); + 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. +// +// See variational_refinement.txt for more information. +class Prewarp { +public: + Prewarp(); + void exec(GLuint tex0_view, GLuint tex1_view, GLuint flow_tex, GLuint I_tex, GLuint I_t_tex, int level_width, int level_height); + +private: + 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, 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); + + GLuint prewarp_fbo; // TODO: cleanup + glCreateFramebuffers(1, &prewarp_fbo); + GLenum bufs[] = { GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1 }; + glNamedFramebufferDrawBuffers(prewarp_fbo, 2, bufs); + glNamedFramebufferTexture(prewarp_fbo, GL_COLOR_ATTACHMENT0, I_tex, 0); + glNamedFramebufferTexture(prewarp_fbo, GL_COLOR_ATTACHMENT1, I_t_tex, 0); + + glViewport(0, 0, level_width, level_height); + glDisable(GL_BLEND); + glBindVertexArray(prewarp_vao); + glBindFramebuffer(GL_FRAMEBUFFER, prewarp_fbo); + 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 +class Derivatives { +public: + Derivatives(); + void exec(GLuint input_tex, GLuint output_tex, int level_width, int level_height); + +private: + 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 output_tex, int level_width, int level_height) +{ + glUseProgram(derivatives_program); + + bind_sampler(derivatives_program, uniform_tex, 0, input_tex, nearest_sampler); + + GLuint derivatives_fbo; // TODO: cleanup + glCreateFramebuffers(1, &derivatives_fbo); + glNamedFramebufferTexture(derivatives_fbo, GL_COLOR_ATTACHMENT0, output_tex, 0); + + glViewport(0, 0, level_width, level_height); + glDisable(GL_BLEND); + glBindVertexArray(derivatives_vao); + glBindFramebuffer(GL_FRAMEBUFFER, derivatives_fbo); + glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); +} int main(void) { @@ -214,84 +545,162 @@ int main(void) GLuint tex0 = load_texture("test1499.pgm", WIDTH, HEIGHT); GLuint tex1 = load_texture("test1500.pgm", WIDTH, HEIGHT); - // Load shaders. - GLuint motion_vs_obj = compile_shader(read_file("vs.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); - - 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); - - // Coarsest level. - int level_width = WIDTH >> coarsest_level; - int level_height = HEIGHT >> coarsest_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); - - // 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 grad_tex; - glCreateTextures(GL_TEXTURE_2D, 1, &grad_tex); - glTextureStorage2D(grad_tex, 1, GL_RG16F, level_width, level_height); - - GLuint grad_fbo; - glCreateFramebuffers(1, &grad_fbo); - glNamedFramebufferTexture(grad_fbo, GL_COLOR_ATTACHMENT0, grad_tex, 0); + // 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); - glUseProgram(sobel_program); - glBindTextureUnit(0, tex0); - 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); + 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); - // 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); - int 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)); - - glBindBuffer(GL_ARRAY_BUFFER, 0); - - // Now finally draw. - glViewport(0, 0, level_width, level_height); - glBindFramebuffer(GL_FRAMEBUFFER, grad_fbo); - glUseProgram(sobel_program); - glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); - glUseProgram(0); - glBindFramebuffer(GL_FRAMEBUFFER, 0); - glBindVertexArray(0); - - GLuint flow_tex; - glCreateTextures(GL_TEXTURE_2D, 1, &flow_tex); - glTextureStorage2D(flow_tex, 1, GL_RG16F, width_patches, height_patches); + // Initial flow is zero, 1x1. + GLuint initial_flow_tex; + glCreateTextures(GL_TEXTURE_2D, 1, &initial_flow_tex); + glTextureStorage2D(initial_flow_tex, 1, GL_RGB32F, 1, 1); + + GLuint prev_level_flow_tex = initial_flow_tex; + + Sobel sobel; + MotionSearch motion_search; + Densify densify; + Prewarp prewarp; + Derivatives derivatives; + + GLuint query; + glGenQueries(1, &query); + glBeginQuery(GL_TIME_ELAPSED, query); + + for (int level = coarsest_level; level >= int(finest_level); --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. + // 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; + glCreateTextures(GL_TEXTURE_2D, 1, &grad0_tex); + glTextureStorage2D(grad0_tex, 1, GL_RG16F, level_width, level_height); + + // Find the derivative. + 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; + glCreateTextures(GL_TEXTURE_2D, 1, &flow_out_tex); + glTextureStorage2D(flow_out_tex, 1, GL_RGB16F, width_patches, height_patches); + + // And draw. + motion_search.exec(tex0_view, tex1_view, grad0_tex, prev_level_flow_tex, flow_out_tex, level_width, level_height, width_patches, height_patches); + + // Densification. + + // Set up an output texture (initially zero). + GLuint dense_flow_tex; + glCreateTextures(GL_TEXTURE_2D, 1, &dense_flow_tex); + glTextureStorage2D(dense_flow_tex, 1, GL_RGB16F, level_width, level_height); + + // And draw. + densify.exec(tex0_view, tex1_view, flow_out_tex, dense_flow_tex, level_width, level_height, width_patches, height_patches); + + // Everything below here in the loop belongs to variational refinement. + // It is not done yet. + + // Prewarping; create I and I_t. + GLuint I_tex, I_t_tex; + glCreateTextures(GL_TEXTURE_2D, 1, &I_tex); + glCreateTextures(GL_TEXTURE_2D, 1, &I_t_tex); + glTextureStorage2D(I_tex, 1, GL_R16F, level_width, level_height); + glTextureStorage2D(I_t_tex, 1, GL_R16F, level_width, level_height); + prewarp.exec(tex0_view, tex1_view, dense_flow_tex, I_tex, I_t_tex, level_width, level_height); + + // Derivatives of the images. 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.) + + // Calculate I_x and I_y. + GLuint I_x_y_tex; + glCreateTextures(GL_TEXTURE_2D, 1, &I_x_y_tex); + glTextureStorage2D(I_x_y_tex, 1, GL_RG16F, level_width, level_height); + derivatives.exec(I_tex, I_x_y_tex, level_width, level_height); + + prev_level_flow_tex = dense_flow_tex; + } + glEndQuery(GL_TIME_ELAPSED); + + GLint available; + do { + glGetQueryObjectiv(query, GL_QUERY_RESULT_AVAILABLE, &available); + usleep(1000); + } while (!available); + GLuint64 time_elapsed; + glGetQueryObjectui64v(query, GL_QUERY_RESULT, &time_elapsed); + fprintf(stderr, "GPU time used = %.1f ms\n", time_elapsed / 1e6); + + int level_width = WIDTH >> finest_level; + int level_height = HEIGHT >> finest_level; + unique_ptr dense_flow(new float[level_width * level_height * 3]); + glGetTextureImage(prev_level_flow_tex, 0, GL_RGB, GL_FLOAT, level_width * level_height * 3 * sizeof(float), dense_flow.get()); + + FILE *fp = fopen("flow.ppm", "wb"); + FILE *flowfp = fopen("flow.flo", "wb"); + fprintf(fp, "P6\n%d %d\n255\n", level_width, level_height); + fprintf(flowfp, "FEIH"); + fwrite(&level_width, 4, 1, flowfp); + fwrite(&level_height, 4, 1, flowfp); + for (unsigned y = 0; y < unsigned(level_height); ++y) { + int yy = level_height - y - 1; + for (unsigned x = 0; x < unsigned(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 = (du / w) * level_width; + dv = (-dv / w) * level_height; + + fwrite(&du, 4, 1, flowfp); + fwrite(&dv, 4, 1, flowfp); + + uint8_t r, g, b; + flow2rgb(du, dv, &r, &g, &b); + putc(r, fp); + putc(g, fp); + putc(b, fp); + } + } + fclose(fp); + fclose(flowfp); -// printf("%d x %d patches on this level\n", width_patches, height_patches); + fprintf(stderr, "err = %d\n", glGetError()); }