public VolumeFalloffEngineData ConvertToEngineData()
{
VolumeFalloffEngineData data = new VolumeFalloffEngineData();
data.weight = weight;
// Clamp to avoid NaNs.
float3 fadePositive = this.fadePositive;
float3 fadeNegative = this.fadeNegative;
data.rcpFaceFadePos.x = (fadePositive.x < 1e-5f) ? float.MaxValue : (1.0f / fadePositive.x);
data.rcpFaceFadePos.y = (fadePositive.y < 1e-5f) ? float.MaxValue : (1.0f / fadePositive.y);
data.rcpFaceFadePos.z = (fadePositive.z < 1e-5f) ? float.MaxValue : (1.0f / fadePositive.z);
data.rcpFaceFadeNeg.y = (fadeNegative.x < 1e-5f) ? float.MaxValue : (1.0f / fadeNegative.x);
data.rcpFaceFadeNeg.x = (fadeNegative.y < 1e-5f) ? float.MaxValue : (1.0f / fadeNegative.y);
data.rcpFaceFadeNeg.z = (fadeNegative.z < 1e-5f) ? float.MaxValue : (1.0f / fadeNegative.z);
float distFadeLen = Mathf.Max(0.00001526f, distanceFadeEnd - distanceFadeStart);
data.rcpDistFadeLen = 1.0f / distFadeLen;
data.endTimesRcpDistFadeLen = distanceFadeEnd * data.rcpDistFadeLen;
return(data);
}
public static float Evaluate(ref VolumeFalloffEngineData falloff, ref OrientedBBox obb, float3 positionWS, float distanceWS)
{
float3x3 obbFrame = new float3x3(obb.right, obb.up, math.cross(obb.up, obb.right));
float3 obbExtents = new float3(obb.extentX, obb.extentY, obb.extentZ);
float3 samplePositionBS = math.mul(obbFrame, positionWS - obb.center);
float3 samplePositionBCS = samplePositionBS / obbExtents;
bool isInsideVolume = math.max(math.abs(samplePositionBCS.x), math.max(math.abs(samplePositionBCS.y), math.abs(samplePositionBCS.z))) < 1.0f;
if (!isInsideVolume)
{
return(0.0f);
}
float3 samplePositionBNDC = samplePositionBCS * 0.5f + 0.5f;
float volumeWeight = VolumeFalloff.ComputeVolumeFalloffWeight(
samplePositionBNDC,
distanceWS,
falloff.rcpFaceFadePos,
falloff.rcpFaceFadeNeg,
falloff.rcpDistFadeLen,
falloff.endTimesRcpDistFadeLen
);
volumeWeight *= falloff.weight;
return(volumeWeight);
}
