84 lines
2.6 KiB
HLSL
84 lines
2.6 KiB
HLSL
#ifndef GEO_UTILITIES_H
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#define GEO_UTILITIES_H
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#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Common.hlsl"
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#include "Packages/com.unity.render-pipelines.core/ShaderLibrary/Packing.hlsl"
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struct CylinderBound
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{
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float3 center;
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float3 axis;
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float halfHeight;
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float capRadius;
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};
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struct SphereBound
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{
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float3 center;
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float radius;
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};
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float CompleteSinCos(float sinOrCos)
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{
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return sqrt(max(1.0f - sinOrCos*sinOrCos, 0.0f));
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}
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float2 ProjectedHalfLengths(CylinderBound cylinder, float3 planeNormal)
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{
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float absCosTheta = abs(dot(planeNormal, cylinder.axis));
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float sinTheta = CompleteSinCos(absCosTheta);
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float h = cylinder.halfHeight;
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float r = cylinder.capRadius;
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float halfLengthAlongNormal = absCosTheta * h + sinTheta * r;
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float halfLengthInPlane = max(sinTheta * h + absCosTheta * r, r); // ellipse, so use max of two axis lengths
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return float2(halfLengthInPlane, halfLengthAlongNormal);
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}
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struct BoundingObjectData
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{
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float3 frontCenterPosRWS;
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float2 centerPosNDC;
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float2 radialPosNDC;
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};
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BoundingObjectData CalculateBoundingObjectData(SphereBound boundingSphere,
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float4x4 viewProjMatrix,
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float4 viewOriginWorldSpace,
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float4 radialDirWorldSpace,
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float4 facingDirWorldSpace)
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{
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const float3 centerPosRWS = boundingSphere.center - viewOriginWorldSpace.xyz;
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const float3 radialVec = abs(boundingSphere.radius) * radialDirWorldSpace.xyz;
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const float3 facingVec = abs(boundingSphere.radius) * facingDirWorldSpace.xyz;
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BoundingObjectData data;
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data.centerPosNDC = ComputeNormalizedDeviceCoordinates(centerPosRWS, viewProjMatrix);
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data.radialPosNDC = ComputeNormalizedDeviceCoordinates(centerPosRWS + radialVec, viewProjMatrix);
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data.frontCenterPosRWS = centerPosRWS + facingVec;
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return data;
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}
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BoundingObjectData CalculateBoundingObjectData(CylinderBound cylinderBound,
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float4x4 viewProjMatrix,
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float4 viewOriginWorldSpace,
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float4 radialDirWorldSpace,
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float4 facingDirWorldSpace)
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{
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const float3 centerPosRWS = cylinderBound.center - viewOriginWorldSpace.xyz;
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const float2 halfLengths = ProjectedHalfLengths(cylinderBound, facingDirWorldSpace.xyz);
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const float3 radialVec = halfLengths.x * radialDirWorldSpace.xyz;
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BoundingObjectData data;
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data.centerPosNDC = ComputeNormalizedDeviceCoordinates(centerPosRWS, viewProjMatrix);
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data.radialPosNDC = ComputeNormalizedDeviceCoordinates(centerPosRWS + radialVec, viewProjMatrix);
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data.frontCenterPosRWS = centerPosRWS + halfLengths.y * facingDirWorldSpace.xyz;
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return data;
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}
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#endif
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