]> git.sesse.net Git - nageru/commitdiff
Start working on interpolation code.
authorSteinar H. Gunderson <sgunderson@bigfoot.com>
Mon, 30 Jul 2018 16:08:23 +0000 (18:08 +0200)
committerSteinar H. Gunderson <sgunderson@bigfoot.com>
Mon, 30 Jul 2018 16:26:26 +0000 (18:26 +0200)
blend.frag [new file with mode: 0644]
flow.cpp
splat.frag [new file with mode: 0644]
splat.vert [new file with mode: 0644]

diff --git a/blend.frag b/blend.frag
new file mode 100644 (file)
index 0000000..154538e
--- /dev/null
@@ -0,0 +1,35 @@
+#version 450 core
+
+in vec2 tc;
+out vec4 rgba;
+
+uniform sampler2D image0_tex, image1_tex, flow_tex;
+uniform float alpha, flow_consistency_tolerance;
+
+void main()
+{
+       vec2 flow = texture(flow_tex, tc).xy;
+       vec4 I_0 = texture(image0_tex, tc - alpha * flow);
+       vec4 I_1 = texture(image1_tex, tc + (1.0f - alpha) * flow);
+
+       // Occlusion reasoning:
+
+       vec2 size = textureSize(image0_tex, 0);
+
+       // Follow the flow back to the initial point (where we sample I_0 from), then forward again.
+       // See how well we match the point we started at, which is out flow consistency.
+       float d0 = alpha * length(size * (texture(flow_tex, tc - alpha * flow).xy - flow));
+
+       // Same for d1.
+       float d1 = (1.0f - alpha) * length(size * (texture(flow_tex, tc + (1.0f - alpha) * flow).xy - flow));
+
+       if (max(d0, d1) < 3.0f) {  // Arbitrary constant, not all that tuned. The UW paper says 1.0 is fine for ground truth.
+               // Both are visible, so blend.
+               rgba = I_0 + alpha * (I_1 - I_0);
+       } else if (d0 < d1) {
+               rgba = I_0;
+       } else {
+               rgba = I_1;
+       }
+
+}
index 6bed6d7c9c659713760e62867b67500725532b87..ac9238759054939ee91345dda2206968691321ca 100644 (file)
--- a/flow.cpp
+++ b/flow.cpp
@@ -28,6 +28,8 @@
 
 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 = 5;
@@ -45,6 +47,7 @@ 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.
@@ -149,7 +152,12 @@ GLuint compile_shader(const string &shader_src, GLenum type)
        return obj;
 }
 
-GLuint load_texture(const char *filename, unsigned *width_ret, unsigned *height_ret)
+enum MipmapPolicy {
+       WITHOUT_MIPMAPS,
+       WITH_MIPMAPS
+};
+
+GLuint load_texture(const char *filename, unsigned *width_ret, unsigned *height_ret, MipmapPolicy mipmaps)
 {
        SDL_Surface *surf = IMG_Load(filename);
        if (surf == nullptr) {
@@ -178,11 +186,17 @@ GLuint load_texture(const char *filename, unsigned *width_ret, unsigned *height_
        }
        SDL_FreeSurface(rgb_surf);
 
+       int num_levels = (mipmaps == WITH_MIPMAPS) ? find_num_levels(width, height) : 1;
+
        GLuint tex;
        glCreateTextures(GL_TEXTURE_2D, 1, &tex);
-       glTextureStorage2D(tex, 1, GL_RGBA8, width, height);
+       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;
 
@@ -1069,9 +1083,14 @@ 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);
+       GLuint exec(GLuint tex0, GLuint tex1, ResizeStrategy resize_strategy);
 
        void release_texture(GLuint tex) {
                pool.release_texture(tex);
@@ -1129,7 +1148,7 @@ DISComputeFlow::DISComputeFlow(int width, int height)
        glClearTexImage(initial_flow_tex, 0, GL_RG, GL_FLOAT, nullptr);
 }
 
-GLuint DISComputeFlow::exec(GLuint tex0, GLuint tex1)
+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;
@@ -1298,7 +1317,7 @@ GLuint DISComputeFlow::exec(GLuint tex0, GLuint tex1)
        timers.print();
 
        // Scale up the flow to the final size (if needed).
-       if (finest_level == 0) {
+       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);
@@ -1308,6 +1327,217 @@ GLuint DISComputeFlow::exec(GLuint tex0, GLuint tex1)
        }
 }
 
+// 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.
+       glCreateVertexArrays(1, &splat_vao);
+       glBindVertexArray(splat_vao);
+       glBindBuffer(GL_ARRAY_BUFFER, vertex_vbo);
+
+       GLint position_attrib = glGetAttribLocation(splat_program, "position");
+       glEnableVertexArrayAttrib(splat_vao, position_attrib);
+       glVertexAttribPointer(position_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");
+}
+
+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 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 / 
+
+       glViewport(0, 0, level_width, level_height);
+       fbos.render_to(output_tex);
+       glBindVertexArray(blend_vao);
+       glUseProgram(blend_program);
+       glDisable(GL_BLEND);  // A bit ironic, perhaps.
+       glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+}
+
+class Interpolate {
+public:
+       Interpolate(int width, int height, int flow_level);
+
+       // 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);
+
+       void release_texture(GLuint tex) {
+               pool.release_texture(tex);
+       }
+
+private:
+       int width, height, flow_level;
+       TexturePool pool;
+       Splat splat;
+       Blend blend;
+};
+
+Interpolate::Interpolate(int width, int height, int flow_level)
+       : width(width), height(height), flow_level(flow_level) {}
+
+GLuint Interpolate::exec(GLuint tex0, GLuint tex1, GLuint forward_flow_tex, GLuint backward_flow_tex, GLuint width, GLuint height, float alpha)
+{
+       GPUTimers timers;
+
+       ScopedTimer total_timer("Total", &timers);
+
+       // 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 = 1000000.0f;
+               glClearTexImage(depth_tex, 0, GL_DEPTH_COMPONENT, GL_FLOAT, &infinity);
+       }
+
+       //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();
+
+       return output_tex;
+}
+
 GLuint TexturePool::get_texture(GLenum format, GLuint width, GLuint height)
 {
        for (Texture &tex : textures) {
@@ -1417,74 +1647,16 @@ void schedule_read(GLuint tex, GLuint width, GLuint height, const char *filename
        glBindBuffer(GL_PIXEL_PACK_BUFFER, 0);
 }
 
-int main(int argc, char **argv)
+void compute_flow_only(int argc, char **argv, int optind)
 {
-        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.
-       };
-
-       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;
-               default:
-                       fprintf(stderr, "Unknown option '%s'\n", argv[option_index]);
-                       exit(1);
-               };
-       }
-
-       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);
-       SDL_Window *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);
-
        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);
-       GLuint tex1 = load_texture(filename1, &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",
@@ -1494,24 +1666,12 @@ int main(int argc, char **argv)
 
        // Set up some PBOs to do asynchronous readback.
        GLuint pbos[5];
-        glCreateBuffers(5, pbos);
+       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]);
        }
 
-       // 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);
-
        int levels = find_num_levels(width1, height1);
        GLuint tex0_gray, tex1_gray;
        glCreateTextures(GL_TEXTURE_2D, 1, &tex0_gray);
@@ -1529,7 +1689,7 @@ int main(int argc, char **argv)
        glGenerateTextureMipmap(tex1_gray);
 
        DISComputeFlow compute_flow(width1, height1);
-       GLuint final_tex = compute_flow.exec(tex0_gray, tex1_gray);
+       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);
@@ -1542,7 +1702,7 @@ int main(int argc, char **argv)
                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);
+               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);
@@ -1552,7 +1712,7 @@ int main(int argc, char **argv)
                glGenerateTextureMipmap(tex0_gray);
                glDeleteTextures(1, &tex0);
 
-               GLuint tex1 = load_texture(filename1, &width, &height);
+               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);
@@ -1562,7 +1722,7 @@ int main(int argc, char **argv)
                glGenerateTextureMipmap(tex1_gray);
                glDeleteTextures(1, &tex1);
 
-               GLuint final_tex = compute_flow.exec(tex0_gray, tex1_gray);
+               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);
@@ -1574,3 +1734,161 @@ int main(int argc, char **argv)
                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);
+               };
+       }
+
+       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);
+       }
+}
diff --git a/splat.frag b/splat.frag
new file mode 100644 (file)
index 0000000..c06667b
--- /dev/null
@@ -0,0 +1,20 @@
+#version 450 core
+
+in vec2 image_pos;
+flat in vec2 flow, I_0_check_offset, I_1_check_offset;
+out vec2 out_flow;
+
+uniform sampler2D image0_tex, image1_tex;
+
+void main()
+{
+       out_flow = flow;
+
+       // TODO: Check if we are sampling out-of-image.
+       // TODO: See whether using intensity values gives equally good results
+       // as RGB, since the rest of our pipeline is intensity.
+       vec3 I_0 = texture(image0_tex, image_pos + I_0_check_offset).rgb;
+       vec3 I_1 = texture(image1_tex, image_pos + I_1_check_offset).rgb;
+       vec3 diff = abs(I_1 - I_0);
+       gl_FragDepth = diff.x + diff.y + diff.z;
+}
diff --git a/splat.vert b/splat.vert
new file mode 100644 (file)
index 0000000..4a1ecd7
--- /dev/null
@@ -0,0 +1,44 @@
+#version 450 core
+
+in vec2 position;
+out vec2 image_pos;
+flat out vec2 flow, I_0_check_offset, I_1_check_offset;
+
+uniform bool invert_flow;
+uniform vec2 splat_size;  // In 0..1 coordinates.
+uniform vec2 inv_flow_size;
+uniform float alpha;
+uniform sampler2D flow_tex;
+
+void main()
+{
+       int x = gl_InstanceID % textureSize(flow_tex, 0).x;
+       int y = gl_InstanceID / textureSize(flow_tex, 0).x;
+
+       // Find out where to splat this to.
+       // TODO: See if we can move some of these calculations into uniforms.
+       vec2 full_flow = texelFetch(flow_tex, ivec2(x, y), 0).xy;
+       float splat_alpha;
+       if (invert_flow) {
+               full_flow = -full_flow;
+               splat_alpha = 1.0f - alpha;
+       } else {
+               splat_alpha = alpha;
+       }
+       full_flow *= inv_flow_size;
+       
+       vec2 patch_center = (ivec2(x, y) + 0.5) / textureSize(flow_tex, 0) + full_flow * splat_alpha;
+       image_pos = patch_center + splat_size * (position - 0.5);
+
+       flow = full_flow;
+       I_0_check_offset = full_flow * -alpha;
+       I_1_check_offset = full_flow * (1.0f - alpha);
+
+       // The result of glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0) is:
+       //
+       //   2.000  0.000  0.000 -1.000
+       //   0.000  2.000  0.000 -1.000
+       //   0.000  0.000 -2.000 -1.000
+       //   0.000  0.000  0.000  1.000
+       gl_Position = vec4(2.0 * image_pos.x - 1.0, 2.0 * image_pos.y - 1.0, -1.0, 1.0);
+}