private Color traceRay(Ray ray, Scene scene, int depth)
{
var isect = this.intersections(ray, scene);
if (isect == null)
{
return Color.background;
}
else
{
return this.shade(isect, scene, depth);
}
}
private float? testRay(Ray ray, Scene scene)
{
var isect = this.intersections(ray, scene);
if (isect != null)
{
return isect.dist;
}
else
{
return null;
}
}
private Intersection intersections(Ray ray, Scene scene)
{
float closest = float.MaxValue;
Intersection closestInter = null;
foreach (var thing in scene.things)
{
var inter = thing.intersect(ray);
if (inter != null)
{
if (inter.dist < closest)
{
closestInter = inter;
closest = inter.dist;
}
}
}
return closestInter;
}
private Color shade(Intersection isect, Scene scene, int depth)
{
var d = isect.ray.Direction;
var pos = (isect.dist * d) + isect.ray.Position;
var normal = isect.thing.normal(pos);
var reflectDir = d - ((normal * Vector3.Dot(normal, d)) * 2.0f);
var naturalColor = Color.plus(Color.background,
this.getNaturalColor(isect.thing, pos, normal, reflectDir, scene));
var reflectedColor = (depth >= this.maxDepth) ? Color.grey : this.getReflectionColor(isect.thing, pos, normal, reflectDir, scene, depth);
return Color.plus(naturalColor, reflectedColor);
}
public void render(Scene scene, Device device, int screenWidth, int screenHeight)
{
var output = new System.Drawing.Color[screenWidth, screenHeight];
Parallel.ForEach(Enumerable.Range(0, screenHeight), (y) =>
{
Parallel.ForEach(Enumerable.Range(0, screenWidth), (x) =>
{
var color = this.traceRay(new Ray { Position = scene.camera.pos, Direction = getPoint(screenWidth, screenHeight, x, y, scene.camera) }, scene, 0);
var c = Color.toDrawingColor(color);
output[x, y] = c;
});
});
for (int x = 0; x < screenWidth; x++)
{
for (int y = 0; y < screenHeight; y++)
{
device.DrawPixel(x, y, output[x, y]);
}
}
}
private Color getNaturalColor(Object3D thing, Vector3 pos, Vector3 norm, Vector3 rd, Scene scene)
{
List<Color> colors = new List<Color>();
foreach (var light in scene.lights)
{
var ldis = light.pos - pos;
var livec = Vector3.Normalize(ldis);
var neatIsect = this.testRay(new Ray { Position = pos, Direction = livec }, scene);
var isInShadow = (neatIsect == null) ? false : neatIsect.Value <= ldis.Length();
if (isInShadow)
{
colors.Add(Color.defaultColor);
}
else
{
var illum = Vector3.Dot(livec, norm);
var lcolor = (illum > 0) ? Color.scale(illum, light.color) : Color.defaultColor;
var specular = Vector3.Dot(livec, Vector3.Normalize(rd));
var scolor = (specular > 0) ? Color.scale((float)System.Math.Pow(specular, thing.surface.roughness), light.color) : Color.defaultColor;
var outc = Color.plus(Color.defaultColor, Color.plus(Color.times(thing.surface.diffuse(pos), lcolor), Color.times(thing.surface.specular(pos), scolor)));
colors.Add(outc);
}
}
var cl = new Color(0, 0, 0);
foreach (var c in colors)
{
cl.r += c.r;
cl.g += c.g;
cl.b += c.b;
}
return cl;
}
private Color getReflectionColor(Object3D thing, Vector3 pos, Vector3 normal, Vector3 rd, Scene scene, int depth)
{
var n = thing.surface.reflect(pos);
var c = this.traceRay(new Ray { Position = pos, Direction = rd }, scene, depth + 1);
return Color.scale(thing.surface.reflect(pos), c);
}
