fix: use premultiplied alpha blend state and account for sRGB transfo…

…rmation
mosure · Nov 27, 2023 · b99751f · b99751f
1 parent 46a9524
commit b99751f
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Showing 2 changed files with 14 additions and 13 deletions.
diff --git a/src/render/mod.rs b/src/render/mod.rs
@@ -482,18 +482,7 @@ impl SpecializedRenderPipeline for GaussianCloudPipeline {
                 entry_point: "fs_main".into(),
                 targets: vec![Some(ColorTargetState {
                     format: TextureFormat::Rgba8UnormSrgb,
-                    blend: Some(BlendState {
-                        color: BlendComponent {
-                            src_factor: BlendFactor::One,
-                            dst_factor: BlendFactor::OneMinusSrcAlpha,
-                            operation: BlendOperation::Add,
-                        },
-                        alpha: BlendComponent {
-                            src_factor: BlendFactor::Zero,
-                            dst_factor: BlendFactor::OneMinusSrcAlpha,
-                            operation: BlendOperation::Add,
-                        },
-                    }),
+                    blend: Some(BlendState::PREMULTIPLIED_ALPHA_BLENDING),
                     write_mask: ColorWrites::ALL,
                 })],
             }),

diff --git a/src/render/spherical_harmonics.wgsl b/src/render/spherical_harmonics.wgsl
@@ -20,6 +20,18 @@ const shc = array<f32, 16>(
     -0.5900435899266435,
 );
 
+fn srgb_to_linear(srgb_color: vec3<f32>) -> vec3<f32> {
+    var linear_color: vec3<f32>;
+    for (var i = 0u; i < 3u; i = i + 1u) {
+        if (srgb_color[i] <= 0.04045) {
+            linear_color[i] = srgb_color[i] / 12.92;
+        } else {
+            linear_color[i] = pow((srgb_color[i] + 0.055) / 1.055, 2.4);
+        }
+    }
+    return linear_color;
+}
+
 fn spherical_harmonics_lookup(
     ray_direction: vec3<f32>,
     sh: array<f32, #{MAX_SH_COEFF_COUNT}>,
@@ -47,5 +59,5 @@ fn spherical_harmonics_lookup(
     color += shc[14] * vec3<f32>(sh[42], sh[43], sh[44]) * ray_direction.z * (rds.x - rds.y);
     color += shc[15] * vec3<f32>(sh[45], sh[46], sh[47]) * ray_direction.x * (rds.x - 3.0 * rds.y);
 
-    return color;
+    return srgb_to_linear(color);
 }