Update multipass shader test

shaders/multipass-test/shader.slang

@@ -17,19 +17,18 @@ float gridMask(float2 uv)
 float4 buildMask(ShaderContext context)
 {
 	float mask = saturate(max(ringMask(context.uv), gridMask(context.uv)));
-	return float4(mask, context.uv.x, context.uv.y, 1.0);
+	return float4(context.sourceColor.rgb, mask);
 }
 
 float4 applyMask(ShaderContext context)
 {
 	float4 generated = sampleVideo(context.uv);
-	float mask = generated.r;
-	float2 encodedUv = generated.gb;
-	float checker = step(0.5, frac((encodedUv.x + encodedUv.y) * max(scale, 1.0)));
+	float mask = generated.a;
+	float checker = step(0.5, frac((context.uv.x + context.uv.y) * max(scale, 1.0)));
 	float3 testColor = lerp(float3(0.0, 0.75, 1.0), float3(1.0, 0.1, 0.85), checker);
-	float3 base = context.sourceColor.rgb * 0.35;
+	float3 base = generated.rgb;
 	float3 color = lerp(base, testColor, mask * saturate(intensity));
-	return float4(color, context.sourceColor.a);
+	return float4(color, 1.0);
 }
 
 float4 shadeVideo(ShaderContext context)