diff --git a/src/render/colormap.wgsl b/src/render/colormap.wgsl
index e2af29d..0e7db5b 100644
--- a/src/render/colormap.wgsl
+++ b/src/render/colormap.wgsl
@@ -14,9 +14,10 @@ struct Varying {
 
 @group(0) @binding(0) var<uniform> look: LookParams;
 
-fn colormap(light: f32) -> vec3f {
-	let brightness = 3. * (1. - 1. / (1. + light));
-	return vec3(brightness, brightness - 1., brightness - 2.);
+fn colormap(light: vec3f) -> vec3f {
+	let avg = dot(light, vec3f(1. / 3.));
+	let scale = 1. / (1. + avg);
+	return scale * light;
 }
 
 @vertex
@@ -28,5 +29,5 @@ fn on_vertex(in: Vertex) -> Varying {
 
 @fragment
 fn on_fragment(in: Varying) -> @location(0) vec4f {
-	return vec4f(colormap(in.color.x), 1.0);
+	return vec4f(colormap(in.color.rgb), in.color.a);
 }