Final BxDF changes, drafts of Spherical Shape Sampling, RWMC and PAth Tracing

include/nbl/builtin/hlsl/cpp_compat/impl/intrinsics_impl.hlsl

@@ -968,8 +968,19 @@ struct mix_helper<T, T NBL_PARTIAL_REQ_BOT(VECTOR_SPECIALIZATION_CONCEPT && !imp
 	}
 };
 
-template<typename T, typename U> NBL_PARTIAL_REQ_TOP((concepts::Vectorial<T> || concepts::Scalar<T>) && concepts::Boolean<U> && !impl::MixCallingBuiltins<T, U>)
-struct mix_helper<T, U NBL_PARTIAL_REQ_BOT((concepts::Vectorial<T> || concepts::Scalar<T>) && concepts::Boolean<U> && !impl::MixCallingBuiltins<T, U>) >
+namespace impl
+{
+template<typename T, typename U>
+NBL_BOOL_CONCEPT MixCallingSelect =
+#ifdef __HLSL_VERSION
+spirv::SelectIsCallable<T, U>;
+#else
+concepts::Boolean<U> && (concepts::Scalar<U> || (concepts::Vector<T> && vector_traits<T>::Dimension==vector_traits<U>::Dimension)) && !MixCallingBuiltins<T, U>;
+#endif
+}
+
+template<typename T, typename U> NBL_PARTIAL_REQ_TOP(impl::MixCallingSelect<T, U>)
+struct mix_helper<T, U NBL_PARTIAL_REQ_BOT(impl::MixCallingSelect<T, U>) >
 {
 	using return_t = T;
 	static return_t __call(NBL_CONST_REF_ARG(T) x, NBL_CONST_REF_ARG(T) y, NBL_CONST_REF_ARG(U) a)

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

@@ -69,12 +69,9 @@ struct CascadeAccumulator
     // most of this code is stolen from https://cg.ivd.kit.edu/publications/2018/rwmc/tool/split.cpp
     void addSample(uint32_t sampleCount, input_sample_type _sample)
     {
-        const float32_t2 unpackedParams = hlsl::unpackHalf2x16(splattingParameters.packedLog2);
-        const cascade_layer_scalar_type log2Start = unpackedParams[0];
-        const cascade_layer_scalar_type log2Base = unpackedParams[1];
         const cascade_layer_scalar_type luma = getLuma(_sample);
         const cascade_layer_scalar_type log2Luma = log2<cascade_layer_scalar_type>(luma);
-        const cascade_layer_scalar_type cascade = log2Luma * 1.f / log2Base - log2Start / log2Base;
+        const cascade_layer_scalar_type cascade = log2Luma * splattingParameters.rcpLog2Base - splattingParameters.baseRootOfStart;
         const cascade_layer_scalar_type clampedCascade = clamp(cascade, 0, CascadeCount - 1);
         // c<=0 -> 0, c>=Count-1 -> Count-1 
         uint32_t lowerCascadeIndex = floor<cascade_layer_scalar_type>(cascade);
@@ -85,7 +82,11 @@ struct CascadeAccumulator
 
         // handle super bright sample case
         if (cascade > CascadeCount - 1)
+        {
+            const cascade_layer_scalar_type log2Base = cascade_layer_scalar_type(1.0) / splattingParameters.rcpLog2Base;
+            const cascade_layer_scalar_type log2Start = splattingParameters.baseRootOfStart * log2Base;
             lowerCascadeWeight = exp2(log2Start + log2Base * (CascadeCount - 1) - log2Luma);
+        }
 
         accumulation.addSampleIntoCascadeEntry(_sample, lowerCascadeIndex, lowerCascadeWeight, higherCascadeWeight, sampleCount);
     }

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

@@ -2,6 +2,7 @@
 #define _NBL_BUILTIN_HLSL_RWMC_SPLATTING_PARAMETERS_HLSL_INCLUDED_
 
 #include "nbl/builtin/hlsl/cpp_compat.hlsl"
+#include "nbl/builtin/hlsl/tgmath.hlsl"
 
 namespace nbl
 {
@@ -12,10 +13,18 @@ namespace rwmc
 
 struct SplattingParameters
 {
-    // float16_t log2Start; 0
-    // float16_t log2Base; 1
-    // pack as Half2x16
-    int32_t packedLog2;
+    using scalar_t = float;
+
+    static SplattingParameters create(const scalar_t base, const scalar_t start)
+    {
+        SplattingParameters retval;
+        retval.rcpLog2Base = scalar_t(1.0) / hlsl::log2(base);
+        retval.baseRootOfStart = hlsl::log2(start) * retval.rcpLog2Base;
+        return retval;
+    }
+
+    scalar_t baseRootOfStart;
+    scalar_t rcpLog2Base;
 };
 
 }

include/nbl/builtin/hlsl/rwmc/resolve.hlsl

@@ -48,8 +48,6 @@ struct ResolveAccessorAdaptor
 	using output_type = vector<OutputScalar, 4>;
 	NBL_CONSTEXPR int32_t image_dimension = 2;
 
-	RWTexture2DArray<float32_t4> cascade;
-
 	float32_t calcLuma(NBL_REF_ARG(float32_t3) col)
 	{
 		return hlsl::dot<float32_t3>(colorspace::scRGB::ToXYZ()[1], col);

include/nbl/builtin/hlsl/shapes/spherical_triangle.hlsl

@@ -102,29 +102,6 @@ struct SphericalTriangle
     vector3_type csc_sides;
 };
 
-namespace util
-{
-  // Use this convetion e_i = v_{i+2}-v_{i+1}. vertex index is modulo by 3.
-  template <typename float_t>
-  vector<float_t, 3> compInternalAngle(const vector<float_t, 3> e0, vector<float_t, 3> e1, const vector<float_t, 3> e2)
-  {
-    // Calculate this triangle's weight for each of its three m_vertices
-    // start by calculating the lengths of its sides
-    const float_t a = hlsl::dot(e0, e0);
-    const float_t asqrt = hlsl::sqrt(a);
-    const float_t b = hlsl::dot(e1, e1);
-    const float_t bsqrt = hlsl::sqrt(b);
-    const float_t c = hlsl::dot(e2, e2);
-    const float_t csqrt = hlsl::sqrt(c);
-
-    const float_t angle0 = hlsl::acos((b + c - a) / (2.f * bsqrt * csqrt));
-    const float_t angle1 = hlsl::acos((-b + c + a) / (2.f * asqrt * csqrt));
-    const float_t angle2 = hlsl::numbers::pi<float_t> - (angle0 + angle1);
-    // use them to find the angle at each vertex
-    return vector<float_t, 3>(angle0, angle1, angle2);
-  }
-}
-
 }
 }
 }

include/nbl/builtin/hlsl/shapes/triangle.hlsl

@@ -0,0 +1,46 @@
+// Copyright (C) 2018-2025 - DevSH Graphics Programming Sp. z O.O.
+// This file is part of the "Nabla Engine".
+// For conditions of distribution and use, see copyright notice in nabla.h
+
+#ifndef _NBL_BUILTIN_HLSL_SHAPES_TRIANGLE_INCLUDED_
+#define _NBL_BUILTIN_HLSL_SHAPES_TRIANGLE_INCLUDED_
+
+#include <nbl/builtin/hlsl/cpp_compat.hlsl>
+#include <nbl/builtin/hlsl/tgmath.hlsl>
+#include <nbl/builtin/hlsl/numbers.hlsl>
+
+namespace nbl
+{
+namespace hlsl
+{
+namespace shapes
+{
+
+namespace util
+{
+    // Use this convetion e_i = v_{i+2}-v_{i+1}. vertex index is modulo by 3.
+    template <typename float_t>
+    vector<float_t, 3> anglesFromTriangleEdge(const vector<float_t, 3> e0, vector<float_t, 3> e1, const vector<float_t, 3> e2)
+    {
+        // Calculate this triangle's weight for each of its three m_vertices
+        // start by calculating the lengths of its sides
+        const float_t a = hlsl::dot(e0, e0);
+        const float_t asqrt = hlsl::sqrt(a);
+        const float_t b = hlsl::dot(e1, e1);
+        const float_t bsqrt = hlsl::sqrt(b);
+        const float_t c = hlsl::dot(e2, e2);
+        const float_t csqrt = hlsl::sqrt(c);
+
+        const float_t angle0 = hlsl::acos((b + c - a) / (2.f * bsqrt * csqrt));
+        const float_t angle1 = hlsl::acos((-b + c + a) / (2.f * asqrt * csqrt));
+        const float_t angle2 = hlsl::numbers::pi<float_t> - (angle0 + angle1);
+        // use them to find the angle at each vertex
+        return vector<float_t, 3>(angle0, angle1, angle2);
+    }
+}
+
+}
+}
+}
+
+#endif

src/nbl/asset/utils/CSmoothNormalGenerator.cpp

@@ -5,7 +5,7 @@
 #include "CSmoothNormalGenerator.h"
 
 #include "nbl/core/declarations.h"
-#include "nbl/builtin/hlsl/shapes/spherical_triangle.hlsl"
+#include "nbl/builtin/hlsl/shapes/triangle.hlsl"
 
 #include <algorithm>
 
@@ -58,7 +58,7 @@ CSmoothNormalGenerator::VertexHashMap CSmoothNormalGenerator::setupData(const as
 		const auto faceNormal = normalize(cross(v1 - v0, v2 - v0));
 
 		//set data for m_vertices
-		const auto angleWages = hlsl::shapes::util::compInternalAngle(v2 - v1, v0 - v2, v1 - v2);
+		const auto angleWages = hlsl::shapes::util::anglesFromTriangleEdge(v2 - v1, v0 - v2, v1 - v2);
 
 		vertices.add({ i,	0,	faceNormal * angleWages.x, v0});
 		vertices.add({ i + 1,	0,	faceNormal * angleWages.y,v1});

src/nbl/builtin/CMakeLists.txt

@@ -253,6 +253,7 @@ LIST_BUILTIN_RESOURCE(NBL_RESOURCES_TO_EMBED "hlsl/shapes/circle.hlsl")
 LIST_BUILTIN_RESOURCE(NBL_RESOURCES_TO_EMBED "hlsl/shapes/ellipse.hlsl")
 LIST_BUILTIN_RESOURCE(NBL_RESOURCES_TO_EMBED "hlsl/shapes/line.hlsl")
 LIST_BUILTIN_RESOURCE(NBL_RESOURCES_TO_EMBED "hlsl/shapes/beziers.hlsl")
+LIST_BUILTIN_RESOURCE(NBL_RESOURCES_TO_EMBED "hlsl/shapes/triangle.hlsl")
 LIST_BUILTIN_RESOURCE(NBL_RESOURCES_TO_EMBED "hlsl/shapes/spherical_triangle.hlsl")
 LIST_BUILTIN_RESOURCE(NBL_RESOURCES_TO_EMBED "hlsl/shapes/spherical_rectangle.hlsl")
 LIST_BUILTIN_RESOURCE(NBL_RESOURCES_TO_EMBED "hlsl/shapes/aabb.hlsl")