Start working on variational refinement.

[nageru] / flow.cpp

diff --git a/flow.cpp b/flow.cpp
index b46e0a10c74cff067b2a5c67675baece2adfe329..87cc06f1a510f7af39d21283d0cd4f53bf243bfc 100644 (file)
--- a/flow.cpp
+++ b/flow.cpp
@@ -404,6 +404,67 @@ void Densify::exec(GLuint tex0_view, GLuint tex1_view, GLuint flow_tex, GLuint d
        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);
+}
+
 int main(void)
 {
        if (SDL_Init(SDL_INIT_EVERYTHING) == -1) {
@@ -464,6 +525,7 @@ int main(void)
        Sobel sobel;
        MotionSearch motion_search;
        Densify densify;
+       Prewarp prewarp;
 
        GLuint query;
        glGenQueries(1, &query);
@@ -516,7 +578,16 @@ int main(void)
                // 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);
 
                prev_level_flow_tex = dense_flow_tex;
        }