Fixup

src/render/draw_atmosphere.js

@@ -64,13 +64,6 @@ function drawAtmosphere(painter: Painter) {
         skyColor.a
     ];
     const spaceColor = fog.properties.get('space-color');
-    const spaceColorUnpremultiplied = [
-        spaceColor.a === 0.0 ? 0 : spaceColor.r / spaceColor.a,
-        spaceColor.a === 0.0 ? 0 : spaceColor.g / spaceColor.a,
-        spaceColor.a === 0.0 ? 0 : spaceColor.b / spaceColor.a,
-        spaceColor.a
-    ];
-
     const temporalOffset = (painter.frameCounter / 1000.0) % 1;
     const latlon = [
         degToRad(transform._center.lat) / (Math.PI * 0.5),
@@ -90,7 +83,7 @@ function drawAtmosphere(painter: Painter) {
         fog.properties.get('horizon-blend'),
         fogColorUnpremultiplied,
         skyColorUnpremultiplied,
-        spaceColorUnpremultiplied,
+        [spaceColor.r, spaceColor.g, spaceColor.b, spaceColor.a],
         latlon,
         starIntensity,
         temporalOffset);

src/shaders/atmosphere.fragment.glsl

@@ -61,16 +61,14 @@ void main() {
     vec3 c1 = mix(c0, color_stop_0, alpha_0);
     vec3 c2 = mix(c0, c1, t);
     vec3 c3 = mix(color_stop_2, c2, t);
-
-    vec3 color = c2 * t + c3 * (1.0 - t);
+    vec3 c  = mix(c3, c2, t);
 
     // Blend alphas
     float a0 = mix(alpha_2, 1.0, alpha_1);
     float a1 = mix(a0, 1.0, alpha_0);
     float a2 = mix(a0, a1, t);
     float a3 = mix(alpha_2, a2, t);
-
-    float composited_alpha = a2 * t + a3 * (1.0 - t);
+    float a  = mix(a3, a2, t);
 
     vec2 uv = (gl_FragCoord.xy / u_viewport) * (2.0 - 1.0);
     vec3 D = vec3(uv + vec2(-u_latlon.y, -u_latlon.x), 1.0);
@@ -89,10 +87,10 @@ void main() {
     star_field *= (1.0 - pow(t, 0.25 + (1.0 - u_sky_color.a) * 0.75));
 
     // Additive star field
-    color = color + star_field * alpha_2;
+    c = c + star_field * alpha_2;
 
     // Dither
-    color = dither(color, gl_FragCoord.xy + u_temporal_offset);
+    c = dither(c, gl_FragCoord.xy + u_temporal_offset);
 
-    gl_FragColor = vec4(color, composited_alpha);
+    gl_FragColor = vec4(c, a);
 }