Do not use native trig function in sun baking

(because of poor precision)
sergcpp · Jun 18, 2024 · fa2e151 · fa2e151
1 parent ca8fd6d
commit fa2e151
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Showing 8 changed files with 36 additions and 19 deletions.
diff --git a/internal/RendererGPU_kernels.h b/internal/RendererGPU_kernels.h
@@ -862,6 +862,8 @@ inline void Ray::NS::Renderer::kernel_ShadeSky(CommandBuffer cmd_buf, const pass
             memcpy(uniform_params.light_dir, l.dir.dir, 3 * sizeof(float));
             uniform_params.light_dir[3] = l.dir.angle;
             memcpy(uniform_params.light_col, l.col, 3 * sizeof(float));
+            memcpy(uniform_params.light_col_point, l.col, 3 * sizeof(float));
+            uniform_params.light_col[3] = cosf(l.dir.angle);
             if (l.dir.angle != 0.0f) {
                 const float radius = tanf(l.dir.angle);
                 uniform_params.light_col[0] *= (PI * radius * radius);
@@ -881,6 +883,8 @@ inline void Ray::NS::Renderer::kernel_ShadeSky(CommandBuffer cmd_buf, const pass
         memcpy(uniform_params.light_dir, value_ptr(light_dir), 3 * sizeof(float));
         uniform_params.light_dir[3] = 0.0f;
         memcpy(uniform_params.light_col, value_ptr(light_col), 3 * sizeof(float));
+        memcpy(uniform_params.light_col_point, value_ptr(light_col), 3 * sizeof(float));
+        uniform_params.light_col[3] = 0.0f;
 
         DispatchComputeIndirect(cmd_buf, pi_shade_sky_, indir_args, indir_args_index * sizeof(DispatchIndirectCommand),
                                 bindings, &uniform_params, sizeof(uniform_params), ctx_->default_descr_alloc(),

diff --git a/internal/SceneGPU.h b/internal/SceneGPU.h
@@ -1598,6 +1598,14 @@ inline void Ray::NS::Scene::Rebuild_SWRT_TLAS_nolock() {
     tlas_root_node_ = bvh_nodes[0];
 }
 
+//#define DUMP_SKY_ENV
+#ifdef DUMP_SKY_ENV
+extern "C" {
+int SaveEXR(const float *data, int width, int height, int components, const int save_as_fp16, const char *outfilename,
+            const char **err);
+}
+#endif
+
 inline std::vector<Ray::color_rgba8_t> Ray::NS::Scene::CalcSkyEnvTexture(const atmosphere_params_t &params,
                                                                          const int res[2], const light_t lights[],
                                                                          Span<const uint32_t> dir_lights) {
@@ -1651,6 +1659,8 @@ inline std::vector<Ray::color_rgba8_t> Ray::NS::Scene::CalcSkyEnvTexture(const a
                 memcpy(uniform_params.light_dir, l.dir.dir, 3 * sizeof(float));
                 uniform_params.light_dir[3] = l.dir.angle;
                 memcpy(uniform_params.light_col, l.col, 3 * sizeof(float));
+                memcpy(uniform_params.light_col_point, l.col, 3 * sizeof(float));
+                uniform_params.light_col[3] = cosf(l.dir.angle);
                 if (l.dir.angle != 0.0f) {
                     const float radius = tanf(l.dir.angle);
                     uniform_params.light_col[0] *= (PI * radius * radius);
@@ -1669,6 +1679,8 @@ inline std::vector<Ray::color_rgba8_t> Ray::NS::Scene::CalcSkyEnvTexture(const a
             memcpy(uniform_params.light_dir, value_ptr(light_dir), 3 * sizeof(float));
             uniform_params.light_dir[3] = 0.0f;
             memcpy(uniform_params.light_col, value_ptr(light_col), 3 * sizeof(float));
+            memcpy(uniform_params.light_col_point, value_ptr(light_col), 3 * sizeof(float));
+            uniform_params.light_col[3] = 0.0f;
 
             DispatchCompute(cmd_buf, pi_bake_sky_, grp_count, bindings, &uniform_params, sizeof(uniform_params),
                             ctx_->default_descr_alloc(), ctx_->log());
@@ -1690,6 +1702,10 @@ inline std::vector<Ray::color_rgba8_t> Ray::NS::Scene::CalcSkyEnvTexture(const a
     std::vector<color_rgba8_t> rgbe_pixels(res[0] * res[1]);
 
     const float *f32_data = reinterpret_cast<const float *>(temp_readback_buf.Map());
+#ifdef DUMP_SKY_ENV
+    const char *err = nullptr;
+    SaveEXR(f32_data, res[0], res[1], 4, 0, "sky.exr", &err);
+#endif
     for (int i = 0; i < res[0] * res[1]; ++i) {
         Ref::fvec4 color(&f32_data[4 * i]);
         color = rgb_to_rgbe(color);

diff --git a/internal/shaders/output/bake_sky.comp.cso.inl b/internal/shaders/output/bake_sky.comp.cso.inl
diff --git a/internal/shaders/output/bake_sky.comp.spv.inl b/internal/shaders/output/bake_sky.comp.spv.inl
diff --git a/internal/shaders/output/shade_sky.comp.cso.inl b/internal/shaders/output/shade_sky.comp.cso.inl
diff --git a/internal/shaders/output/shade_sky.comp.spv.inl b/internal/shaders/output/shade_sky.comp.spv.inl
diff --git a/internal/shaders/shade_sky.comp.glsl b/internal/shaders/shade_sky.comp.glsl
@@ -616,13 +616,9 @@ vec3 IntegrateScattering(vec3 ray_start, const vec3 ray_dir, float ray_length, u
     // Sun disk (bake directional light into the texture)
     //
     if (g_params.light_dir.w > 0.0 && planet_intersection.x < 0.0 && light_brightness > 0.0) {
-        const float cos_theta = cos(g_params.light_dir.w);
-        vec3 sun_disk = total_transmittance * smoothstep(cos_theta - SKY_SUN_BLEND_VAL, cos_theta + SKY_SUN_BLEND_VAL, costh);
-        // 'de-multiply' by disk area (to get original brightness)
-        const float radius = tan(g_params.light_dir.w);
-        sun_disk /= (PI * radius * radius);
-
-        total_radiance += sun_disk * g_params.light_col.xyz;
+        const float cos_theta = g_params.light_col.w;
+        const vec3 sun_disk = total_transmittance * smoothstep(cos_theta - SKY_SUN_BLEND_VAL, cos_theta + SKY_SUN_BLEND_VAL, costh);
+        total_radiance += sun_disk * g_params.light_col_point.xyz;
     }
 
     //

diff --git a/internal/shaders/shade_sky_interface.h b/internal/shaders/shade_sky_interface.h
@@ -8,6 +8,7 @@ INTERFACE_START(ShadeSky)
 struct Params {
     vec4 light_dir;
     vec4 light_col;
+    vec4 light_col_point;
     vec4 env_col;
     vec4 back_col;
     //