internal static System.Drawing.Color[,] Render(int screenWidth, int screenHeight, int numSamples, Scene scene)
{
System.Drawing.Color[,] pixels = new System.Drawing.Color[screenWidth, screenHeight];
Camera camera = scene.Camera;
F64 sx = F64.Ratio(1, 2 * screenWidth);
F64 ox = F64.Half * F64.FromInt(screenWidth);
F64 sy = -F64.Ratio(1, 2 * screenHeight);
F64 oy = F64.Half * F64.FromInt(screenHeight);
F32 ooNumSamples = F32.Ratio(1, numSamples);
//for (int y = 0; y < screenHeight; y++)
Parallel.For(0, screenHeight, y =>
{
Random rnd = new Random(y * 29827341 + 23427343);
for (int x = 0; x < screenWidth; x++)
{
Color accum = Color.Black;
for (int i = 0; i < numSamples; i++)
{
// rx, ry == random offset in range [-0.5, 0.5]
F64 rx = F64.FromRaw(rnd.Next()) * 2 - F64.Half;
F64 ry = F64.FromRaw(rnd.Next()) * 2 - F64.Half;
F64 xx = (F64.FromInt(x) + rx - ox) * sx;
F64 yy = (F64.FromInt(y) + ry - oy) * sy;
F64Vec3 rayDir = F64Vec3.Normalize(camera.Forward + xx * camera.Right + yy * camera.Up);
Color color = TraceRay(new Ray(camera.Pos, rayDir), scene, 0);
accum += color;
}
pixels[x, y] = (ooNumSamples * accum).ToDrawingColor();
}
});
return(pixels);
}
private static Color Shade(Ray ray, ISect isect, Scene scene, int depth)
{
var pos = isect.Pos;
var normal = isect.Normal;
var reflectDir = ray.Dir - 2 * F64Vec3.Dot(normal, ray.Dir) * normal;
Color ret = Color.Black;
Material material = isect.Material;
ret += GetNaturalColor(material, pos, normal, reflectDir, scene);
if (depth >= MaxDepth)
{
return(ret + new Color(F32.Half, F32.Half, F32.Half));
}
return(ret + GetReflectionColor(material, pos + F64.Ratio(1, 1000) * reflectDir, normal, reflectDir, scene, depth));
}