#define NO_SDL_GLEXT 1
-#define WIDTH 1280
-#define HEIGHT 720
-
#include <epoxy/gl.h>
#include <SDL2/SDL.h>
#include <SDL2/SDL_video.h>
#include <assert.h>
+#include <getopt.h>
#include <stdio.h>
+#include <unistd.h>
+
+#include "util.h"
#include <algorithm>
+#include <deque>
#include <memory>
+#include <map>
+#include <stack>
+#include <vector>
#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<GLuint> spare_pbos;
+deque<ReadInProgress> 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");
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<uint8_t[]> 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<uint8_t[]> 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) {
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;
}
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<size_t num_elements>
+class PersistentFBOSet {
+public:
+ void render_to(const array<GLuint, num_elements> &textures);
+
+ // Convenience wrappers.
+ void render_to(GLuint texture0, enable_if<num_elements == 1> * = nullptr) {
+ render_to({{texture0}});
+ }
+
+ void render_to(GLuint texture0, GLuint texture1, enable_if<num_elements == 2> * = nullptr) {
+ render_to({{texture0, texture1}});
+ }
+
+ void render_to(GLuint texture0, GLuint texture1, GLuint texture2, enable_if<num_elements == 3> * = nullptr) {
+ render_to({{texture0, texture1, texture2}});
+ }
+
+ void render_to(GLuint texture0, GLuint texture1, GLuint texture2, GLuint texture3, enable_if<num_elements == 4> * = nullptr) {
+ render_to({{texture0, texture1, texture2, texture3}});
+ }
+
+private:
+ // TODO: Delete these on destruction.
+ map<array<GLuint, num_elements>, GLuint> fbos;
+};
+
+template<size_t num_elements>
+void PersistentFBOSet<num_elements>::render_to(const array<GLuint, num_elements> &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<GLuint, GLuint> begin_timer(const string &name, int level);
+
+private:
+ struct Timer {
+ string name;
+ int level;
+ pair<GLuint, GLuint> query;
+ };
+ vector<Timer> timers;
+};
+
+pair<GLuint, GLuint> 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<GLuint, GLuint> 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<Texture> 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<float[]> 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<uint8_t[]> 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);
+ }
}
projects / nageru / blobdiff