changes to splatting params precompute for the last time

Author: keptsecret

include/nbl/builtin/hlsl/rwmc/CascadeAccumulator.hlsl

@@ -82,7 +82,7 @@ struct CascadeAccumulator
 
         // handle super bright sample case
         if (cascade > CascadeCount - 1)
-            lowerCascadeWeight = exp2(splattingParameters.log2Start + splattingParameters.log2Base * (CascadeCount - 1) - log2Luma);
+            lowerCascadeWeight = splattingParameters.lastCascadeLuma / luma;
 
         accumulation.addSampleIntoCascadeEntry(_sample, lowerCascadeIndex, lowerCascadeWeight, higherCascadeWeight, sampleCount);
     }

include/nbl/builtin/hlsl/rwmc/SplattingParameters.hlsl

@@ -15,18 +15,18 @@ struct SplattingParameters
 {
     using scalar_t = float;
 
-    static SplattingParameters create(const scalar_t base, const scalar_t start)
+    static SplattingParameters create(const scalar_t base, const scalar_t start, const uint32_t cascadeCount)
     {
         SplattingParameters retval;
-        retval.log2Base = hlsl::log2(base);
-        retval.log2Start = hlsl::log2(start);
-        retval.rcpLog2Base = scalar_t(1.0) / retval.log2Base;
-        retval.baseRootOfStart = retval.log2Start * retval.rcpLog2Base;
+        const scalar_t log2Base = hlsl::log2(base);
+        const scalar_t log2Start = hlsl::log2(start);
+        retval.lastCascadeLuma = hlsl::exp2(log2Start + log2Base * (cascadeCount - 1));
+        retval.rcpLog2Base = scalar_t(1.0) / log2Base;
+        retval.baseRootOfStart = log2Start * retval.rcpLog2Base;
         return retval;
     }
 
-    scalar_t log2Base;
-    scalar_t log2Start;
+    scalar_t lastCascadeLuma;
     scalar_t baseRootOfStart;
     scalar_t rcpLog2Base;
 };