Only sample analytic lights when they are present (#249)

pierremoreau · web-flow · commit 63c77d4313c2 · 2020-08-06T15:15:49.000-07:00
diff --git a/Source/RenderPasses/MinimalPathTracer/MinimalPathTracer.rt.slang b/Source/RenderPasses/MinimalPathTracer/MinimalPathTracer.rt.slang
@@ -209,6 +209,8 @@ float3 evalDirectAnalytic(const ShadingData sd, float3 rayOrigin, inout SampleGe
 {
     // Pick one of the analytic light sources randomly with equal probability.
     const uint lightCount = gScene.getLightCount();
+    if (lightCount == 0) return float3(0);
+
     const uint lightIndex = min(uint(sampleNext1D(sg) * lightCount), lightCount - 1);
     float invPdf = lightCount; // Light selection pdf = 1.0 / lightCount.
 

Original file line number	Diff line number	Diff line change
`@@ -209,6 +209,8 @@ float3 evalDirectAnalytic(const ShadingData sd, float3 rayOrigin, inout SampleGe`
`209`	`209`	`{`
`210`	`210`	`// Pick one of the analytic light sources randomly with equal probability.`
`211`	`211`	`const uint lightCount = gScene.getLightCount();`
	`212`	`+ if (lightCount == 0) return float3(0);`
	`213`	`+`
`212`	`214`	`const uint lightIndex = min(uint(sampleNext1D(sg) * lightCount), lightCount - 1);`
`213`	`215`	`float invPdf = lightCount; // Light selection pdf = 1.0 / lightCount.`
`214`	`216`