private Color GetNaturalColor(SceneObject thing, Vector pos, Vector norm, Vector rd, Scene scene)
{
Color ret = Color.Make(0, 0, 0);
foreach (Light light in scene.Lights)
{
Vector ldis = Vector.Minus(light.Pos, pos);
Vector livec = Vector.Norm(ldis);
double neatIsect = TestRay(new Ray()
{
Start = pos, Dir = livec
}, scene);
bool isInShadow = !((neatIsect > Vector.Mag(ldis)) || (neatIsect == 0));
if (!isInShadow)
{
double illum = Vector.Dot(livec, norm);
Color lcolor = illum > 0 ? Color.Times(illum, light.Color) : Color.Make(0, 0, 0);
double specular = Vector.Dot(livec, Vector.Norm(rd));
Color scolor = specular > 0 ? Color.Times(Math.Pow(specular, thing.Surface.Roughness), light.Color) : Color.Make(0, 0, 0);
ret = Color.Plus(ret, Color.Plus(Color.Times(thing.Surface.Diffuse(pos), lcolor),
Color.Times(thing.Surface.Specular(pos), scolor)));
}
}
return(ret);
}
private Color Shade(ISect isect, Scene scene, int depth)
{
var d = isect.Ray.Dir;
var pos = Vector.Plus(Vector.Times(isect.Dist, isect.Ray.Dir), isect.Ray.Start);
var normal = isect.Thing.Normal(pos);
var reflectDir = Vector.Minus(d, Vector.Times(2 * Vector.Dot(normal, d), normal));
Color ret = Color.DefaultColor;
ret = Color.Plus(ret, GetNaturalColor(isect.Thing, pos, normal, reflectDir, scene));
if (depth >= MaxDepth)
{
return(Color.Plus(ret, Color.Make(.5, .5, .5)));
}
return(Color.Plus(ret, GetReflectionColor(isect.Thing, Vector.Plus(pos, Vector.Times(.001, reflectDir)), normal, reflectDir, scene, depth)));
}
internal void Render(Scene scene)
{
var pixelsQuery =
from y in Enumerable.Range(0, screenHeight)
let recenterY = -(y - (screenHeight / 2.0)) / (2.0 * screenHeight)
select from x in Enumerable.Range(0, screenWidth)
let recenterX = (x - (screenWidth / 2.0)) / (2.0 * screenWidth)
let point =
Vector.Norm(Vector.Plus(scene.Camera.Forward,
Vector.Plus(Vector.Times(recenterX, scene.Camera.Right),
Vector.Times(recenterY, scene.Camera.Up))))
let ray = new Ray()
{
Start = scene.Camera.Pos, Dir = point
}
let computeTraceRay = (Func <Func <TraceRayArgs, Color>, Func <TraceRayArgs, Color> >)
(f => traceRayArgs =>
(from isect in
from thing in traceRayArgs.Scene.Things
select thing.Intersect(traceRayArgs.Ray)
where isect != null
orderby isect.Dist
let d = isect.Ray.Dir
let pos = Vector.Plus(Vector.Times(isect.Dist, isect.Ray.Dir), isect.Ray.Start)
let normal = isect.Thing.Normal(pos)
let reflectDir = Vector.Minus(d, Vector.Times(2 * Vector.Dot(normal, d), normal))
let naturalColors =
from light in traceRayArgs.Scene.Lights
let ldis = Vector.Minus(light.Pos, pos)
let livec = Vector.Norm(ldis)
let testRay = new Ray()
{
Start = pos, Dir = livec
}
let testIsects = from inter in
from thing in traceRayArgs.Scene.Things
select thing.Intersect(testRay)
where inter != null
orderby inter.Dist
select inter
let testIsect = testIsects.FirstOrDefault()
let neatIsect = testIsect == null ? 0 : testIsect.Dist
let isInShadow = !((neatIsect > Vector.Mag(ldis)) || (neatIsect == 0))
where !isInShadow
let illum = Vector.Dot(livec, normal)
let lcolor = illum > 0 ? Color.Times(illum, light.Color) : Color.Make(0, 0, 0)
let specular = Vector.Dot(livec, Vector.Norm(reflectDir))
let scolor = specular > 0
? Color.Times(Math.Pow(specular, isect.Thing.Surface.Roughness),
light.Color)
: Color.Make(0, 0, 0)
select Color.Plus(Color.Times(isect.Thing.Surface.Diffuse(pos), lcolor),
Color.Times(isect.Thing.Surface.Specular(pos), scolor))
let reflectPos = Vector.Plus(pos, Vector.Times(.001, reflectDir))
let reflectColor = traceRayArgs.Depth >= MaxDepth
? Color.Make(.5, .5, .5)
: Color.Times(isect.Thing.Surface.Reflect(reflectPos),
f(new TraceRayArgs(new Ray()
{
Start = reflectPos,
Dir = reflectDir
},
traceRayArgs.Scene,
traceRayArgs.Depth + 1)))
select naturalColors.Aggregate(reflectColor,
(color, natColor) => Color.Plus(color, natColor))
).DefaultIfEmpty(Color.Background).First())
let traceRay = Y(computeTraceRay)
select new { X = x, Y = y, Color = traceRay(new TraceRayArgs(ray, scene, 0)) };
foreach (var row in pixelsQuery)
{
foreach (var pixel in row)
{
setPixel(pixel.X, pixel.Y, pixel.Color);
}
}
}