public Vector3d GetBackSurfaceSample(Vector2d sample)
{
//var sample2d = Sampler.UniformSampleDisk(sample);
var sample2d = Sampler.ConcentricSampleDisk(sample);
return(new Vector3d(ApertureRadius * sample2d));
}
private Vector3d GenerateSampleAtStop(Circle stop, Vector2d sample)
{
var sample2d = Sampler.ConcentricSampleDisk(sample);
return(new Vector3d(
stop.Radius * sample2d.X,
stop.Radius * sample2d.Y,
stop.Z));
}
private void GenerateLensSamplesTexture(int textureId, int tileSize, int sqrtSampleCount, int totalSampleCount, float lensApertureRadius)
{
GL.BindTexture(TextureTarget.Texture3D, textureId);
// size of a group of samples for a single pixel
int bands = 2;
int groupSize = bands * totalSampleCount;
int textureSize = groupSize * tileSize * tileSize;
Sampler sampler = new Sampler();
IntPtr texturePtr = Marshal.AllocHGlobal(Marshal.SizeOf(typeof(float)) * textureSize);
unsafe
{
int zStride = bands * tileSize * tileSize;
for (int y = 0; y < tileSize; y++)
{
for (int x = 0; x < tileSize; x++)
{
float *row = (float *)texturePtr + bands * (y * tileSize + x);
int index = 0;
// Z dimension, totalSampleCount times
foreach (Vector2d sample in
sampler.GenerateJitteredSamples(sqrtSampleCount))
{
Vector2d lensPos = lensApertureRadius *
//2 * (sample - new Vector2d(0.5, 0.5));
Sampler.ConcentricSampleDisk(sample);
row[index] = (float)lensPos.X;
row[index + 1] = (float)lensPos.Y;
index += zStride;
}
}
}
}
// TODO: could be an unsigned byte instead of a float
// TODO: two sample pair could be stored in one 4-channel value
GL.TexImage3D(TextureTarget.Texture3D, 0, PixelInternalFormat.Rg32f,
tileSize, tileSize, totalSampleCount, 0,
PixelFormat.Rg, PixelType.Float, texturePtr);
GL.TexParameter(TextureTarget.Texture3D, TextureParameterName.TextureMinFilter, (int)TextureMinFilter.Nearest);
GL.TexParameter(TextureTarget.Texture3D, TextureParameterName.TextureMagFilter, (int)TextureMagFilter.Nearest);
GL.TexParameter(TextureTarget.Texture3D, TextureParameterName.TextureWrapS, (int)TextureWrapMode.Repeat);
GL.TexParameter(TextureTarget.Texture3D, TextureParameterName.TextureWrapT, (int)TextureWrapMode.Repeat);
GL.TexParameter(TextureTarget.Texture3D, TextureParameterName.TextureWrapR, (int)TextureWrapMode.Clamp);
}
private static Func <Vector2d, Vector2d> GetConcentricDiskMapping()
{
return((squarePoint) => 0.5 * (Vector2d.One + Sampler.ConcentricSampleDisk(squarePoint)));
}
