fix linear-sRGB color mismatch

src/lib.rs

@@ -18,7 +18,7 @@ pub struct RedrawArgs {
 impl Default for RedrawArgs {
 	fn default() -> Self {
 		Self {
-			background: vec4(0.05, 0.20, 0.85, 1.00),
+			background: vec4(0.25, 0.49, 0.93, 1.00),
 			cam_yaw: std::f32::consts::FRAC_PI_4,
 			cam_pitch: std::f32::consts::FRAC_PI_6,
 			cam_distance: 3.,
@@ -71,6 +71,31 @@ fn cube(a: f32, b: f32) -> render::mesh::CpuMeshIndexed {
 	mesh
 }
 
+fn srgb_to_linear(color: Vec3) -> Vec3 {
+	color.map(|x| {
+		if x > 0.04045 {
+			((x + 0.055) / 1.055).powf(2.4)
+		} else {
+			x / 12.92
+		}
+	})
+}
+
+fn srgba_to_linear(color: Vec4) -> Vec4 {
+	let alpha = color.w;
+	let color = srgb_to_linear(vec3(color.x, color.y, color.z));
+	vec4(color.x, color.y, color.z, alpha)
+}
+
+fn color_to_wgpu(color: Vec4) -> wgpu::Color {
+	wgpu::Color {
+		r: color.x.into(),
+		g: color.y.into(),
+		b: color.z.into(),
+		a: color.w.into(),
+	}
+}
+
 impl Core {
 	pub fn new(gpu: Gpu, pixel_size: UVec2) -> Self {
 		let Gpu {
@@ -133,12 +158,7 @@ impl Core {
 				depth_slice: None,
 				resolve_target: None,
 				ops: wgpu::Operations {
-					load: wgpu::LoadOp::Clear(wgpu::Color {
-						r: args.background.x.into(),
-						g: args.background.y.into(),
-						b: args.background.z.into(),
-						a: args.background.w.into(),
-					}),
+					load: wgpu::LoadOp::Clear(color_to_wgpu(srgba_to_linear(args.background))),
 					store: wgpu::StoreOp::Store,
 				},
 			})],

ui/src/main_window.ui

@@ -168,8 +168,8 @@
        <property name="color">
         <color>
          <red>0</red>
-         <green>32</green>
-         <blue>60</blue>
+         <green>99</green>
+         <blue>133</blue>
         </color>
        </property>
       </widget>