public List <Ray> RaysForPixel(double px, double py)
{
var rays = new List <Ray>();
var inv = this.Camera.TransformInverse;
var origin = inv * new Point(0, 0, 0);
var pixelSize = this.Camera.PixelSize;
var halfWidth = this.Camera.HalfWidth;
var halfHeight = this.Camera.HalfHeight;
for (var i = 0; i < this.NumSamples; i++)
{
var xOffset = (px + 0.5);
var yOffset = (py + 0.5);
var rx = RandomGeneratorThreadSafe.NextDouble();
var ry = RandomGeneratorThreadSafe.NextDouble();
xOffset += (0.5 - rx);
yOffset += (0.5 - ry);
xOffset *= pixelSize;
yOffset *= pixelSize;
var worldX = halfWidth - xOffset;
var worldY = halfHeight - yOffset;
var pixel = inv * new Point(worldX, worldY, -1);
var direction = (pixel - origin).Normalize();
rays.Add(new Ray(origin, direction, RayType.Primary));
}
return(rays);
}
private Vector RandomInUnitDisk()
{
double r = Math.Sqrt(RandomGeneratorThreadSafe.NextDouble());
double theta = RandomGeneratorThreadSafe.NextDouble() * 2 * Math.PI;
double x = r * Math.Cos(theta);
double y = r * Math.Sin(theta);
return(new Vector(x, y, 0));
}