remove some code duplication for sphere vs. tile overlap

remove some code duplication for sphere vs. tile overlap

Assets/ScriptableRenderLoop/fptl/LightingConvexHullUtils.hlsl

 	return float4(vN, -dot(vN,p0));
 }
 
+bool DoesSphereOverlapTile(float3 dir, float halfTileSizeAtZDistOne, float3 sphCen, float sphRadiusIn)
+{
+	float3 V = dir;		// ray direction down center of tile (does not need to be normalized).
+
+#if 1
+	float3 maxZdir = float3(-sphCen.z*sphCen.x, -sphCen.z*sphCen.y, sphCen.x*sphCen.x + sphCen.y*sphCen.y);		// cross(sphCen,cross(Zaxis,sphCen))
+	float len = length(maxZdir);
+	float scalarProj = len>0.0001 ? (maxZdir.z/len) : len;	// since len>=(maxZdir.z/len) we can use len as an approximate value when len<=epsilon
+	float offs = scalarProj*sphRadiusIn;
+#else
+	float offs = sphRadiusIn;		// more false positives due to larger radius but works too
+#endif
+
+	// enlarge sphere so it overlaps the center of the tile assuming it overlaps the tile to begin with.
+#ifdef LEFT_HAND_COORDINATES
+	float sphRadius = sphRadiusIn + (sphCen.z+offs)*halfTileSizeAtZDistOne;
+#else
+	float sphRadius = sphRadiusIn - (sphCen.z-offs)*halfTileSizeAtZDistOne;
+#endif
+		
+	float a = dot(V,V);
+	float CdotV = dot(sphCen,V);
+	float c = dot(sphCen,sphCen) - sphRadius*sphRadius;
+
+	float fDescDivFour = CdotV*CdotV - a*c;
+
+	return c<0 || (fDescDivFour>0 && CdotV>0);		// if ray hits bounding sphere
+}
+
 
 
 #endif

Assets/ScriptableRenderLoop/fptl/lightlistbuild-bigtile.compute

 	}
 }
 
-
-
-
 #ifdef PERFORM_SPHERICAL_INTERSECTION_TESTS
 void SphericalIntersectionTests(uint threadID, int iNrCoarseLights, float2 screenCoordinate)
 {
 #endif
 
 	float onePixDiagDist = GetOnePixDiagWorldDistAtDepthOne();
-	float worldDistAtDepthOne = 32*onePixDiagDist;		// scale by half a tile
+	float halfTileSizeAtZDistOne = 32*onePixDiagDist;		// scale by half a tile
-
-	int iNrVisib = 0;
-		const float3 center = lgtDat.center.xyz;
-		float fRad = lgtDat.radius;
-
-#if 1
-		float3 maxZdir = float3(-center.z*center.x, -center.z*center.y, center.x*center.x + center.y*center.y);		// cross(center,cross(Zaxis,center))
-		float len = length(maxZdir);
-		float scalarProj = len>0.0001 ? (maxZdir.z/len) : len;	// since len>=(maxZdir.z/len) we can use len as an approximate value when len<=epsilon
-		float fOffs = scalarProj*fRad;
-#else
-		float fOffs = fRad;		// more false positives due to larger radius but works too
-#endif
-
-#ifdef LEFT_HAND_COORDINATES
-		fRad = fRad + (center.z+fOffs)*worldDistAtDepthOne;
-#else
-		fRad = fRad - (center.z-fOffs)*worldDistAtDepthOne;
-#endif
-		
-		float a = dot(V,V);
-		float CdotV = dot(center,V);
-		float c = dot(center,center) - fRad*fRad;
-
-		float fDescDivFour = CdotV*CdotV - a*c;
-		if(!(c<0 || (fDescDivFour>0 && CdotV>0)))		// if ray misses bounding sphere
+		if( !DoesSphereOverlapTile(V, halfTileSizeAtZDistOne, lgtDat.center.xyz, lgtDat.radius) )
 			lightsListLDS[l]=0xffffffff;
 	}
 

Assets/ScriptableRenderLoop/fptl/lightlistbuild-clustered.compute

 #endif
 
 	float onePixDiagDist = GetOnePixDiagWorldDistAtDepthOne();
-	float worldDistAtDepthOne = 8*onePixDiagDist;		// scale by half a tile
+	float halfTileSizeAtZDistOne = 8*onePixDiagDist;		// scale by half a tile
 	
 
 	int iNrVisib = 0;
-	
-		const float3 center = lgtDat.center.xyz;
-		float fRad = lgtDat.radius;
-#if 1
-		float3 maxZdir = float3(-center.z*center.x, -center.z*center.y, center.x*center.x + center.y*center.y);		// cross(center,cross(Zaxis,center))
-		float len = length(maxZdir);
-		float scalarProj = len>0.0001 ? (maxZdir.z/len) : len;	// since len>=(maxZdir.z/len) we can use len as an approximate value when len<=epsilon
-		float fOffs = scalarProj*fRad;
-#else
-		float fOffs = fRad;		// more false positives due to larger radius but works too
-#endif
-
-#ifdef LEFT_HAND_COORDINATES
-		fRad = fRad + (center.z+fOffs)*worldDistAtDepthOne;
-#else
-		fRad = fRad - (center.z-fOffs)*worldDistAtDepthOne;
-#endif
-		
-		float a = dot(V,V);
-		float CdotV = dot(center,V);
-		float c = dot(center,center) - fRad*fRad;
-
-		float fDescDivFour = CdotV*CdotV - a*c;
-		if(!(c<0 || (fDescDivFour>0 && CdotV>0)))		// if ray misses bounding sphere
+		if( !DoesSphereOverlapTile(V, halfTileSizeAtZDistOne, lgtDat.center.xyz, lgtDat.radius) )
 			coarseList[l]=0xffffffff;
 	}
 

Assets/ScriptableRenderLoop/fptl/lightlistbuild.compute

 #include "..\common\ShaderBase.h"
 #include "LightDefinitions.cs.hlsl"
 
+#include "LightingConvexHullUtils.hlsl"
+
+
 #define FINE_PRUNING_ENABLED
 #define PERFORM_SPHERICAL_INTERSECTION_TESTS
 
 #endif
 
 	float onePixDiagDist = GetOnePixDiagWorldDistAtDepthOne();
-	float worldDistAtDepthOne = 8*onePixDiagDist;		// scale by half a tile
+	float halfTileSizeAtZDistOne = 8*onePixDiagDist;		// scale by half a tile
 	
 
 	int iNrVisib = 0;
 	
-		const float3 center = lightData.center.xyz;
-		float fRad = lightData.radius;
-
-#if 1
-		float3 maxZdir = float3(-center.z*center.x, -center.z*center.y, center.x*center.x + center.y*center.y);		// cross(center,cross(Zaxis,center))
-		float len = length(maxZdir);
-		float scalarProj = len>0.0001 ? (maxZdir.z/len) : len;	// since len>=(maxZdir.z/len) we can use len as an approximate value when len<=epsilon
-		float fOffs = scalarProj*fRad;
-#else
-		float fOffs = fRad;		// more false positives due to larger radius but works too
-#endif
-
-#ifdef LEFT_HAND_COORDINATES
-		fRad = fRad + (center.z+fOffs)*worldDistAtDepthOne;
-#else
-		fRad = fRad - (center.z-fOffs)*worldDistAtDepthOne;
-#endif
-		
-		float a = dot(V,V);
-		float CdotV = dot(center,V);
-		float c = dot(center,center) - fRad*fRad;
-
-		float fDescDivFour = CdotV*CdotV - a*c;
-		if(c<0 || (fDescDivFour>0 && CdotV>0))		// if ray hit bounding sphere
+		if( DoesSphereOverlapTile(V, halfTileSizeAtZDistOne, lightData.center.xyz, lightData.radius) )
 		{
 			unsigned int uIndex;
 			InterlockedAdd(lightOffsSph, 1, uIndex);