clean up the code a bit more, address comments in #173

Author: devsh

71_RayTracingPipeline/app_resources/common.hlsl

@@ -53,6 +53,11 @@ struct Material
     {
         return alpha < 1.0;
     }
+
+    bool alphaTest(const float32_t xi) NBL_CONST_MEMBER_FUNC
+    {
+        return xi > alpha;
+    }
 };
 
 struct MaterialPacked
@@ -67,6 +72,11 @@ struct MaterialPacked
     {
         return alpha != MAX_UNORM_10;
     }
+
+    bool alphaTest(const uint32_t xi) NBL_CONST_MEMBER_FUNC
+    {
+        return (xi>>22) > alpha;
+    }
 };
 
 struct SProceduralGeomInfo
@@ -198,14 +208,6 @@ struct MaterialId
 struct [raypayload] PrimaryPayload
 {
     using generator_t = nbl::hlsl::random::Pcg;
-/* bugged out by https://github.com/microsoft/DirectXShaderCompiler/issues/6464
-    bool nextDiscard(const float32_t alpha)
-    {
-        const uint32_t bitpattern = pcg();
-        const float32_t xi = (float32_t(bitpattern)+0.5f)/float32_t(0xFFFFFFFF);
-        return xi > alpha;
-    }
-*/
 
     float32_t3  worldNormal : read(caller) : write(closesthit);
     float32_t   rayDistance : read(caller) : write(closesthit, miss);
@@ -335,12 +337,9 @@ float32_t3 fetchVertexNormal(int instID, int primID, STriangleGeomInfo geom, flo
         case OT_ICOSPHERE:
         default:
         {
-                n0 = normalize(vk::RawBufferLoad <
-                float3 > (normalVertexBufferAddress + i0 * vertexStride));
-                n1 = normalize(vk::RawBufferLoad <
-                float3 > (normalVertexBufferAddress + i1 * vertexStride));
-                n2 = normalize(vk::RawBufferLoad <
-                float3 > (normalVertexBufferAddress + i2 * vertexStride));
+                n0 = vk::RawBufferLoad < float3 > (normalVertexBufferAddress + i0 * vertexStride);
+                n1 = vk::RawBufferLoad < float3 > (normalVertexBufferAddress + i1 * vertexStride);
+                n2 = vk::RawBufferLoad < float3 > (normalVertexBufferAddress + i2 * vertexStride);
             }
     }
 

71_RayTracingPipeline/app_resources/raytrace.rahit.hlsl

@@ -8,9 +8,7 @@ void main(inout PrimaryPayload payload, in BuiltInTriangleIntersectionAttributes
     const int instID = InstanceID();
     const STriangleGeomInfo geom = vk::RawBufferLoad < STriangleGeomInfo > (pc.triangleGeomInfoBuffer + instID * sizeof(STriangleGeomInfo));
 
-    // Should have been a method of the payload but https://github.com/microsoft/DirectXShaderCompiler/issues/6464 stops it
-    // alpha is quantized to 10 bits
-    const uint32_t bitpattern = payload.pcg()>>22;
-    if (bitpattern > geom.material.alpha)
+    const uint32_t bitpattern = payload.pcg();
+    if (geom.material.alphaTest(bitpattern))
         IgnoreHit();
 }

71_RayTracingPipeline/app_resources/raytrace.rgen.hlsl

@@ -65,6 +65,12 @@ void main()
         }
 
         const float32_t3 worldPosition = pc.camPos + (camDirection * rayDistance);
+
+        // make sure to call with least live state
+        RayLight cLight;
+        cLight.inHitPosition = worldPosition;
+        CallShader(pc.light.type, cLight);
+
         const float32_t3 worldNormal = payload.worldNormal;
 
         Material material;
@@ -80,9 +86,6 @@ void main()
             const MaterialPacked materialPacked = vk::RawBufferLoad<MaterialPacked>(pc.triangleGeomInfoBuffer + materialId.getMaterialIndex() * sizeof(STriangleGeomInfo));
             material = nbl::hlsl::_static_cast<Material>(materialPacked);
         }
-        RayLight cLight;
-        cLight.inHitPosition = worldPosition;
-        CallShader(pc.light.type, cLight);
 
         float32_t attenuation = 1;
 

71_RayTracingPipeline/app_resources/raytrace.rint.hlsl

@@ -18,14 +18,8 @@ float32_t hitSphere(SProceduralGeomInfo s, Ray r)
     float32_t c = dot(oc, oc) - s.radius * s.radius;
     float32_t discriminant = b * b - 4 * a * c;
 
-    if (discriminant < 0)
-    {
-        return -1.0;
-    }
-    else
-    {
-        return (-b - sqrt(discriminant)) / (2.0 * a);
-    }
+    // return whatever, if the discriminant is negative, it will produce a NaN, and NaN will compare false
+    return (-b - sqrt(discriminant)) / (2.0 * a);
 }
 
 [shader("intersection")]