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);
}
}
}
/// <summary>
/// This is the main RayTrace controller algorithm, the core of the RayTracer
/// recursive method setup
/// this does the actual tracing of the ray and determines the color of each pixel
/// supports:
/// - ambient lighting
/// - diffuse lighting
/// - Gloss lighting
/// - shadows
/// - reflections
/// </summary>
/// <param name="info"></param>
/// <param name="ray"></param>
/// <param name="scene"></param>
/// <param name="depth"></param>
/// <returns></returns>
private Color RayTrace(IntersectInfo info, Ray ray, Scene scene, int depth)
{
// calculate ambient light
Color color = info.Color * scene.Background.Ambience;
double shininess = Math.Pow(10, info.Element.Material.Gloss + 1);
foreach (Light light in scene.Lights)
{
// calculate diffuse lighting
Vector v = (light.Position - info.Position).Normalize();
if (RenderDiffuse)
{
double L = v.Dot(info.Normal);
if (L > 0.0f)
{
color += info.Color * light.Color * L;
}
}
// this is the max depth of raytracing.
// increasing depth will calculate more accurate color, however it will
// also take longer (exponentially)
if (depth < 3)
{
// calculate reflection ray
if (RenderReflection && info.Element.Material.Reflection > 0)
{
Ray reflectionray = GetReflectionRay(info.Position, info.Normal, ray.Direction);
IntersectInfo refl = TestIntersection(reflectionray, scene, info.Element);
if (refl.IsHit && refl.Distance > 0)
{
// recursive call, this makes reflections expensive
refl.Color = RayTrace(refl, reflectionray, scene, depth + 1);
}
else // does not reflect an object, then reflect background color
{
refl.Color = scene.Background.Color;
}
color = color.Blend(refl.Color, info.Element.Material.Reflection);
}
//calculate refraction ray
if (RenderRefraction && info.Element.Material.Transparency > 0)
{
Ray refractionray = GetRefractionRay(info.Position, info.Normal, ray.Direction, info.Element.Material.Refraction);
IntersectInfo refr = info.Element.Intersect(refractionray);
if (refr.IsHit)
{
//refractionray = new Ray(refr.Position, ray.Direction);
refractionray = GetRefractionRay(refr.Position, refr.Normal, refractionray.Direction, refr.Element.Material.Refraction);
refr = TestIntersection(refractionray, scene, info.Element);
if (refr.IsHit && refr.Distance > 0)
{
// recursive call, this makes refractions expensive
refr.Color = RayTrace(refr, refractionray, scene, depth + 1);
}
else
{
refr.Color = scene.Background.Color;
}
}
else
{
refr.Color = scene.Background.Color;
}
color = color.Blend(refr.Color, info.Element.Material.Transparency);
}
}
IntersectInfo shadow = new IntersectInfo();
if (RenderShadow)
{
// calculate shadow, create ray from intersection point to light
Ray shadowray = new Ray(info.Position, v);
// find any element in between intersection point and light
shadow = TestIntersection(shadowray, scene, info.Element);
if (shadow.IsHit && shadow.Element != info.Element)
{
// only cast shadow if the found interesection is another
// element than the current element
color *= 0.5 + 0.5 * Math.Pow(shadow.Element.Material.Transparency, 0.5); // Math.Pow(.5, shadow.HitCount);
}
}
// only show highlights if it is not in the shadow of another object
if (RenderHighlights && !shadow.IsHit && info.Element.Material.Gloss > 0)
{
// only show Gloss light if it is not in a shadow of another element.
// calculate Gloss lighting (Phong)
Vector Lv = (info.Element.Position - light.Position).Normalize();
Vector E = (scene.Camera.Position - info.Element.Position).Normalize();
Vector H = (E - Lv).Normalize();
double Glossweight = 0.0;
Glossweight = Math.Pow(Math.Max(info.Normal.Dot(H), 0), shininess);
color += light.Color * (Glossweight);
}
}
// normalize the color
color.Limit();
return(color);
}