Vector3 CalculateSurfaceNormal(Vector3 p)
{
float H = 0.001f;
float dx = DensityFunctions.Density_Func(p + new Vector3(H, 0.0f, 0.0f)) - DensityFunctions.Density_Func(p - new Vector3(H, 0.0f, 0.0f));
float dy = DensityFunctions.Density_Func(p + new Vector3(0.0f, H, 0.0f)) - DensityFunctions.Density_Func(p - new Vector3(0.0f, H, 0.0f));
float dz = DensityFunctions.Density_Func(p + new Vector3(0.0f, 0.0f, H)) - DensityFunctions.Density_Func(p - new Vector3(0.0f, 0.0f, H));
return(Vector3.Normalize(new Vector3(dx, dy, dz)));
}
Vector3 ApproximateZeroCrossingPosition(Vector3 p0, Vector3 p1)
{
// approximate the zero crossing by finding the min value along the edge
float minValue = 100000.0f;
float t = 0.0f;
float currentT = 0.0f;
int steps = 8;
float increment = 1.0f / (float)steps;
while (currentT <= 1.0f)
{
Vector3 p = p0 + ((p1 - p0) * currentT);
float density = Mathf.Abs(DensityFunctions.Density_Func(p));
if (density < minValue)
{
minValue = density;
t = currentT;
}
currentT += increment;
}
return(p0 + ((p1 - p0) * t));
}