]> git.sesse.net Git - nageru/blobdiff - flow.cpp
Fix an issue where we would lose >1 ms for computing flow on NVIDIA, due to lack...
[nageru] / flow.cpp
index bb0c096ae82be72cc9d7eb2154ff4ff357d0a78b..d914d688fa550cdcaf2ad0341992547018c81ffd 100644 (file)
--- a/flow.cpp
+++ b/flow.cpp
@@ -268,19 +268,19 @@ public:
        void render_to(const array<GLuint, num_elements> &textures);
 
        // Convenience wrappers.
-       void render_to(GLuint texture0, enable_if<num_elements == 1> * = nullptr) {
+       void render_to(GLuint texture0) {
                render_to({{texture0}});
        }
 
-       void render_to(GLuint texture0, GLuint texture1, enable_if<num_elements == 2> * = nullptr) {
+       void render_to(GLuint texture0, GLuint texture1) {
                render_to({{texture0, texture1}});
        }
 
-       void render_to(GLuint texture0, GLuint texture1, GLuint texture2, enable_if<num_elements == 3> * = nullptr) {
+       void render_to(GLuint texture0, GLuint texture1, GLuint texture2) {
                render_to({{texture0, texture1, texture2}});
        }
 
-       void render_to(GLuint texture0, GLuint texture1, GLuint texture2, GLuint texture3, enable_if<num_elements == 4> * = nullptr) {
+       void render_to(GLuint texture0, GLuint texture1, GLuint texture2, GLuint texture3) {
                render_to({{texture0, texture1, texture2, texture3}});
        }
 
@@ -311,6 +311,59 @@ void PersistentFBOSet<num_elements>::render_to(const array<GLuint, num_elements>
        glBindFramebuffer(GL_FRAMEBUFFER, fbo);
 }
 
+// Same, but with a depth texture.
+template<size_t num_elements>
+class PersistentFBOSetWithDepth {
+public:
+       void render_to(GLuint depth_tex, const array<GLuint, num_elements> &textures);
+
+       // Convenience wrappers.
+       void render_to(GLuint depth_tex, GLuint texture0) {
+               render_to(depth_tex, {{texture0}});
+       }
+
+       void render_to(GLuint depth_tex, GLuint texture0, GLuint texture1) {
+               render_to(depth_tex, {{texture0, texture1}});
+       }
+
+       void render_to(GLuint depth_tex, GLuint texture0, GLuint texture1, GLuint texture2) {
+               render_to(depth_tex, {{texture0, texture1, texture2}});
+       }
+
+       void render_to(GLuint depth_tex, GLuint texture0, GLuint texture1, GLuint texture2, GLuint texture3) {
+               render_to(depth_tex, {{texture0, texture1, texture2, texture3}});
+       }
+
+private:
+       // TODO: Delete these on destruction.
+       map<pair<GLuint, array<GLuint, num_elements>>, GLuint> fbos;
+};
+
+template<size_t num_elements>
+void PersistentFBOSetWithDepth<num_elements>::render_to(GLuint depth_tex, const array<GLuint, num_elements> &textures)
+{
+       auto key = make_pair(depth_tex, textures);
+
+       auto it = fbos.find(key);
+       if (it != fbos.end()) {
+               glBindFramebuffer(GL_FRAMEBUFFER, it->second);
+               return;
+       }
+
+       GLuint fbo;
+       glCreateFramebuffers(1, &fbo);
+       GLenum bufs[num_elements];
+       glNamedFramebufferTexture(fbo, GL_DEPTH_ATTACHMENT, depth_tex, 0);
+       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);
+
+       fbos[key] = fbo;
+       glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+}
+
 // Convert RGB to grayscale, using Rec. 709 coefficients.
 class GrayscaleConversion {
 public:
@@ -533,6 +586,8 @@ void Densify::exec(GLuint tex0_view, GLuint tex1_view, GLuint flow_tex, GLuint d
        glBlendFunc(GL_ONE, GL_ONE);
        glBindVertexArray(densify_vao);
        fbos.render_to(dense_flow_tex);
+       glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+       glClear(GL_COLOR_BUFFER_BIT);
        glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width_patches * height_patches);
 }
 
@@ -660,7 +715,7 @@ void Derivatives::exec(GLuint input_tex, GLuint I_x_y_tex, GLuint beta_0_tex, in
 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);
+       void exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height, bool zero_diff_flow);
 
 private:
        PersistentFBOSet<2> fbos;
@@ -671,7 +726,7 @@ private:
        GLuint smoothness_vao;
 
        GLuint uniform_flow_tex, uniform_diff_flow_tex;
-       GLuint uniform_alpha;
+       GLuint uniform_alpha, uniform_zero_diff_flow;
 };
 
 ComputeSmoothness::ComputeSmoothness()
@@ -692,15 +747,17 @@ ComputeSmoothness::ComputeSmoothness()
        uniform_flow_tex = glGetUniformLocation(smoothness_program, "flow_tex");
        uniform_diff_flow_tex = glGetUniformLocation(smoothness_program, "diff_flow_tex");
        uniform_alpha = glGetUniformLocation(smoothness_program, "alpha");
+       uniform_zero_diff_flow = glGetUniformLocation(smoothness_program, "zero_diff_flow");
 }
 
-void ComputeSmoothness::exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height)
+void ComputeSmoothness::exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoothness_x_tex, GLuint smoothness_y_tex, int level_width, int level_height, bool zero_diff_flow)
 {
        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);
+       glProgramUniform1i(smoothness_program, uniform_zero_diff_flow, zero_diff_flow);
 
        glViewport(0, 0, level_width, level_height);
 
@@ -730,7 +787,7 @@ void ComputeSmoothness::exec(GLuint flow_tex, GLuint diff_flow_tex, GLuint smoot
 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);
+       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, bool zero_diff_flow);
 
 private:
        PersistentFBOSet<1> fbos;
@@ -744,7 +801,7 @@ private:
        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;
+       GLuint uniform_gamma, uniform_delta, uniform_zero_diff_flow;
 };
 
 SetupEquations::SetupEquations()
@@ -771,9 +828,10 @@ SetupEquations::SetupEquations()
        uniform_smoothness_y_tex = glGetUniformLocation(equations_program, "smoothness_y_tex");
        uniform_gamma = glGetUniformLocation(equations_program, "gamma");
        uniform_delta = glGetUniformLocation(equations_program, "delta");
+       uniform_zero_diff_flow = glGetUniformLocation(equations_program, "zero_diff_flow");
 }
 
-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)
+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, bool zero_diff_flow)
 {
        glUseProgram(equations_program);
 
@@ -786,6 +844,7 @@ void SetupEquations::exec(GLuint I_x_y_tex, GLuint I_t_tex, GLuint diff_flow_tex
        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);
+       glProgramUniform1i(equations_program, uniform_zero_diff_flow, zero_diff_flow);
 
        glViewport(0, 0, level_width, level_height);
        glDisable(GL_BLEND);
@@ -801,7 +860,7 @@ void SetupEquations::exec(GLuint I_x_y_tex, GLuint I_t_tex, GLuint diff_flow_tex
 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, ScopedTimer *sor_timer);
+       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, bool zero_diff_flow, ScopedTimer *sor_timer);
 
 private:
        PersistentFBOSet<1> fbos;
@@ -814,7 +873,7 @@ private:
        GLuint uniform_diff_flow_tex;
        GLuint uniform_equation_tex;
        GLuint uniform_smoothness_x_tex, uniform_smoothness_y_tex;
-       GLuint uniform_phase;
+       GLuint uniform_phase, uniform_zero_diff_flow;
 };
 
 SOR::SOR()
@@ -837,9 +896,10 @@ SOR::SOR()
        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");
+       uniform_zero_diff_flow = glGetUniformLocation(sor_program, "zero_diff_flow");
 }
 
-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, ScopedTimer *sor_timer)
+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, bool zero_diff_flow, ScopedTimer *sor_timer)
 {
        glUseProgram(sor_program);
 
@@ -848,6 +908,8 @@ void SOR::exec(GLuint diff_flow_tex, GLuint equation_tex, GLuint smoothness_x_te
        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);
 
+       glProgramUniform1i(sor_program, uniform_zero_diff_flow, zero_diff_flow);
+
        // 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
@@ -866,6 +928,10 @@ void SOR::exec(GLuint diff_flow_tex, GLuint equation_tex, GLuint smoothness_x_te
                }
                {
                        ScopedTimer timer("Black pass", sor_timer);
+                       if (zero_diff_flow && i == 0) {
+                               // Not zero anymore.
+                               glProgramUniform1i(sor_program, uniform_zero_diff_flow, 0);
+                       }
                        glProgramUniform1i(sor_program, uniform_phase, 1);
                        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
                        if (i != num_iterations - 1) {
@@ -1121,9 +1187,8 @@ GLuint DISComputeFlow::exec(GLuint tex0, GLuint tex1, ResizeStrategy resize_stra
 
                // Densification.
 
-               // Set up an output texture (initially zero).
+               // Set up an output texture (cleared in Densify).
                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.
                {
@@ -1167,9 +1232,9 @@ GLuint DISComputeFlow::exec(GLuint tex0, GLuint tex1, ResizeStrategy resize_stra
                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.
+               // to the non-refined base flow u0 and v0). It's initially garbage,
+               // but not read until we've written something sane to it.
                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);
@@ -1184,20 +1249,20 @@ GLuint DISComputeFlow::exec(GLuint tex0, GLuint tex1, ResizeStrategy resize_stra
                        // 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);
+                               compute_smoothness.exec(base_flow_tex, du_dv_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height, outer_idx == 0);
                        }
 
                        // 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);
+                               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, outer_idx == 0);
                        }
 
                        // 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, &timer);
+                               sor.exec(du_dv_tex, equation_tex, smoothness_x_tex, smoothness_y_tex, level_width, level_height, 5, outer_idx == 0, &timer);
                        }
                }
 
@@ -1252,7 +1317,7 @@ public:
        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;
+       PersistentFBOSetWithDepth<1> fbos;
 
        GLuint splat_vs_obj;
        GLuint splat_fs_obj;
@@ -1310,12 +1375,13 @@ void Splat::exec(GLuint tex0, GLuint tex1, GLuint forward_flow_tex, GLuint backw
        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);
+       fbos.render_to(depth_tex, flow_tex);
+
+       // Evidently NVIDIA doesn't use fast clears for glClearTexImage, so clear now that
+       // we've got it bound.
+       glClearColor(1000.0f, 1000.0f, 0.0f, 1.0f);  // Invalid flow.
+       glClearDepth(1.0f);  // Effectively infinity.
+       glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
        // Do forward splatting.
        bind_sampler(splat_program, uniform_flow_tex, 2, forward_flow_tex, nearest_sampler);
@@ -1328,8 +1394,6 @@ void Splat::exec(GLuint tex0, GLuint tex1, GLuint forward_flow_tex, GLuint backw
        glDrawArraysInstanced(GL_TRIANGLE_STRIP, 0, 4, width * height);
 
        glDisable(GL_DEPTH_TEST);
-
-       glDeleteFramebuffers(1, &fbo);
 }
 
 // Doing good and fast hole-filling on a GPU is nontrivial. We choose an option
@@ -1355,7 +1419,7 @@ public:
        void exec(GLuint flow_tex, GLuint depth_tex, GLuint temp_tex[3], int width, int height);
 
 private:
-       PersistentFBOSet<2> fbos;
+       PersistentFBOSetWithDepth<1> fbos;
 
        GLuint fill_vs_obj;
        GLuint fill_fs_obj;
@@ -1400,12 +1464,7 @@ void HoleFill::exec(GLuint flow_tex, GLuint depth_tex, GLuint temp_tex[3], int w
        glDepthFunc(GL_LESS);  // Only update the values > 0.999f (ie., only invalid pixels).
        glBindVertexArray(fill_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);  // NOTE: Reading and writing to the same texture.
-       glNamedFramebufferTexture(fbo, GL_DEPTH_ATTACHMENT, depth_tex, 0);
-       glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+       fbos.render_to(depth_tex, flow_tex);  // NOTE: Reading and writing to the same texture.
 
        // Fill holes from the left, by shifting 1, 2, 4, 8, etc. pixels to the right.
        for (int offs = 1; offs < width; offs *= 2) {
@@ -1443,8 +1502,6 @@ void HoleFill::exec(GLuint flow_tex, GLuint depth_tex, GLuint temp_tex[3], int w
        }
 
        glDisable(GL_DEPTH_TEST);
-
-       glDeleteFramebuffers(1, &fbo);
 }
 
 // Blend the four directions from HoleFill into one pixel, so that single-pixel
@@ -1456,7 +1513,7 @@ public:
        void exec(GLuint flow_tex, GLuint depth_tex, GLuint temp_tex[3], int width, int height);
 
 private:
-       PersistentFBOSet<2> fbos;
+       PersistentFBOSetWithDepth<1> fbos;
 
        GLuint blend_vs_obj;
        GLuint blend_fs_obj;
@@ -1508,18 +1565,11 @@ void HoleBlend::exec(GLuint flow_tex, GLuint depth_tex, GLuint temp_tex[3], int
        glDepthFunc(GL_LEQUAL);  // Skip over all of the pixels that were never holes to begin with.
        glBindVertexArray(blend_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);  // NOTE: Reading and writing to the same texture.
-       glNamedFramebufferTexture(fbo, GL_DEPTH_ATTACHMENT, depth_tex, 0);
-       glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+       fbos.render_to(depth_tex, flow_tex);  // NOTE: Reading and writing to the same texture.
 
        glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
 
        glDisable(GL_DEPTH_TEST);
-
-       glDeleteFramebuffers(1, &fbo);
 }
 
 class Blend {
@@ -1619,13 +1669,6 @@ GLuint Interpolate::exec(GLuint tex0, GLuint tex1, GLuint forward_flow_tex, GLui
 
        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);
-               float invalid_flow[] = { 1000.0f, 1000.0f };
-               glClearTexImage(flow_tex, 0, GL_RG, GL_FLOAT, invalid_flow);
-               float infinity = 1.0f;
-               glClearTexImage(depth_tex, 0, GL_DEPTH_COMPONENT, GL_FLOAT, &infinity);
-       }
 
        {
                ScopedTimer timer("Splat", &total_timer);