public static Vector4 IntegrateOverQuad(this ScatteringProfile profile, Vector3 receiverPosition, PositionedQuad quad)
{
int nearestIdx = quad.FindClosestCorner(receiverPosition);
SubQuad orientedSubQuad = SubQuad.MakeRotatedWhole(nearestIdx);
return(IntegrateOverSubQuad(profile, receiverPosition, quad, orientedSubQuad));
}
private static Vector4 IntegrateOverSubQuad(ScatteringProfile profile, Vector3 receiverPosition, PositionedQuad root, SubQuad subQuad)
{
var quad = subQuad.AsPositionedQuad(root);
double area = quad.Area;
//this assume that P0 is the closest point to the receiver
double closestDistance = Vector3.Distance(receiverPosition, quad.P0);
double maximumContribution = profile.CalculateMaximumContribution(closestDistance, area);
if (maximumContribution < SubdivisionThreshold)
{
double distance = Vector3.Distance(receiverPosition, quad.Center);
return(subQuad.CenterWeight * (float)(area * profile.CalculateDiffuseReflectance(distance)));
}
else
{
Vector4 total = Vector4.Zero;
foreach (SubQuad subSubQuad in subQuad.Split())
{
total += IntegrateOverSubQuad(profile, receiverPosition, root, subSubQuad);
}
return(total);
}
}
