#include <assert.h>
#include <stdio.h>
+#include <unistd.h>
#include "util.h"
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;
+ GLuint uniform_inv_image_size;
+};
+
+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");
+ uniform_inv_image_size = glGetUniformLocation(derivatives_program, "inv_image_size");
+}
+
+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);
+ glProgramUniform2f(derivatives_program, uniform_inv_image_size, 1.0f / level_width, 1.0f / level_height);
+
+ 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)
{
if (SDL_Init(SDL_INIT_EVERYTHING) == -1) {
Sobel sobel;
MotionSearch motion_search;
Densify densify;
+ Prewarp prewarp;
+ Derivatives derivatives;
GLuint query;
glGenQueries(1, &query);
// And draw.
densify.exec(tex0_view, tex1_view, flow_out_tex, dense_flow_tex, level_width, level_height, width_patches, height_patches);
- // TODO: Variational refinement.
+ // 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;
}
GLint available;
do {
glGetQueryObjectiv(query, GL_QUERY_RESULT_AVAILABLE, &available);
+ usleep(1000);
} while (!available);
GLuint64 time_elapsed;
glGetQueryObjectui64v(query, GL_QUERY_RESULT, &time_elapsed);
projects / nageru / blobdiff