private void GenerateRays(int _RaysCount, RendererManaged.StructuredBuffer <RendererManaged.float3> _Target)
{
_RaysCount = Math.Min(MAX_THREADS, _RaysCount);
// Half-Life 2 basis
RendererManaged.float3[] HL2Basis = new RendererManaged.float3[] {
new RendererManaged.float3((float)Math.Sqrt(2.0 / 3.0), 0.0f, (float)Math.Sqrt(1.0 / 3.0)),
new RendererManaged.float3(-(float)Math.Sqrt(1.0 / 6.0), (float)Math.Sqrt(1.0 / 2.0), (float)Math.Sqrt(1.0 / 3.0)),
new RendererManaged.float3(-(float)Math.Sqrt(1.0 / 6.0), -(float)Math.Sqrt(1.0 / 2.0), (float)Math.Sqrt(1.0 / 3.0))
};
float CenterTheta = (float)Math.Acos(HL2Basis[0].z);
float[] CenterPhi = new float[] {
(float)Math.Atan2(HL2Basis[0].y, HL2Basis[0].x),
(float)Math.Atan2(HL2Basis[1].y, HL2Basis[1].x),
(float)Math.Atan2(HL2Basis[2].y, HL2Basis[2].x),
};
for (int RayIndex = 0; RayIndex < _RaysCount; RayIndex++)
{
double Phi = (Math.PI / 3.0) * (2.0 * WMath.SimpleRNG.GetUniform() - 1.0);
// Stratified version
double Theta = (Math.Acos(Math.Sqrt((RayIndex + WMath.SimpleRNG.GetUniform()) / _RaysCount)));
// // Don't give a shit version (a.k.a. melonhead version)
// // double Theta = Math.Acos( Math.Sqrt(WMath.SimpleRNG.GetUniform() ) );
// double Theta = 0.5 * Math.PI * WMath.SimpleRNG.GetUniform();
Theta = Math.Min(0.499f * Math.PI, Theta);
double CosTheta = Math.Cos(Theta);
double SinTheta = Math.Sin(Theta);
double LengthFactor = 1.0 / SinTheta; // The ray is scaled so we ensure we always walk at least a texel in the texture
CosTheta *= LengthFactor;
SinTheta *= LengthFactor; // Yeah, yields 1... :)
_Target.m[0 * MAX_THREADS + RayIndex].Set((float)(Math.Cos(CenterPhi[0] + Phi) * SinTheta),
(float)(Math.Sin(CenterPhi[0] + Phi) * SinTheta),
(float)CosTheta);
_Target.m[1 * MAX_THREADS + RayIndex].Set((float)(Math.Cos(CenterPhi[1] + Phi) * SinTheta),
(float)(Math.Sin(CenterPhi[1] + Phi) * SinTheta),
(float)CosTheta);
_Target.m[2 * MAX_THREADS + RayIndex].Set((float)(Math.Cos(CenterPhi[2] + Phi) * SinTheta),
(float)(Math.Sin(CenterPhi[2] + Phi) * SinTheta),
(float)CosTheta);
}
_Target.Write();
}
private void GenerateRays(int _RaysCount, float _MaxConeAngle, RendererManaged.StructuredBuffer <RendererManaged.float3> _Target)
{
_RaysCount = Math.Min(MAX_THREADS, _RaysCount);
WMath.Hammersley hammersley = new WMath.Hammersley();
double[,] sequence = hammersley.BuildSequence(_RaysCount, 2);
WMath.Vector[] rays = hammersley.MapSequenceToSphere(sequence, 0.5f * _MaxConeAngle);
for (int RayIndex = 0; RayIndex < _RaysCount; RayIndex++)
{
WMath.Vector ray = rays[RayIndex];
// // Scale the ray so we ensure to always walk at least a texel in the texture
// float SinTheta = (float) Math.Sqrt( 1.0 - ray.y * ray.y );
// float LengthFactor = 1.0f / SinTheta;
// ray *= LengthFactor;
_Target.m[RayIndex].Set(ray.x, -ray.z, ray.y);
}
_Target.Write();
}