Skip to content

Instantly share code, notes, and snippets.

@tonetheman
Created June 25, 2013 03:32
Show Gist options
  • Star 1 You must be signed in to star a gist
  • Fork 0 You must be signed in to fork a gist
  • Save tonetheman/5855719 to your computer and use it in GitHub Desktop.
Save tonetheman/5855719 to your computer and use it in GitHub Desktop.
javascript raytracer from typescript playground here http://www.typescriptlang.org/Playground/ this is the translated javascript that typescript pooped out
var Vector = (function () {
function Vector(x, y, z) {
this.x = x;
this.y = y;
this.z = z;
}
Vector.times = function (k, v) {
return new Vector(k * v.x, k * v.y, k * v.z);
};
Vector.minus = function (v1, v2) {
return new Vector(v1.x - v2.x, v1.y - v2.y, v1.z - v2.z);
};
Vector.plus = function (v1, v2) {
return new Vector(v1.x + v2.x, v1.y + v2.y, v1.z + v2.z);
};
Vector.dot = function (v1, v2) {
return v1.x * v2.x + v1.y * v2.y + v1.z * v2.z;
};
Vector.mag = function (v) {
return Math.sqrt(v.x * v.x + v.y * v.y + v.z * v.z);
};
Vector.norm = function (v) {
var mag = Vector.mag(v);
var div = (mag === 0) ? Infinity : 1.0 / mag;
return Vector.times(div, v);
};
Vector.cross = function (v1, v2) {
return new Vector(v1.y * v2.z - v1.z * v2.y, v1.z * v2.x - v1.x * v2.z, v1.x * v2.y - v1.y * v2.x);
};
return Vector;
})();
var Color = (function () {
function Color(r, g, b) {
this.r = r;
this.g = g;
this.b = b;
}
Color.scale = function (k, v) {
return new Color(k * v.r, k * v.g, k * v.b);
};
Color.plus = function (v1, v2) {
return new Color(v1.r + v2.r, v1.g + v2.g, v1.b + v2.b);
};
Color.times = function (v1, v2) {
return new Color(v1.r * v2.r, v1.g * v2.g, v1.b * v2.b);
};
Color.toDrawingColor = function (c) {
var legalize = function (d) {
return d > 1 ? 1 : d;
};
return {
r: Math.floor(legalize(c.r) * 255),
g: Math.floor(legalize(c.g) * 255),
b: Math.floor(legalize(c.b) * 255)
};
};
Color.white = new Color(1.0, 1.0, 1.0);
Color.grey = new Color(0.5, 0.5, 0.5);
Color.black = new Color(0.0, 0.0, 0.0);
Color.background = Color.black;
Color.defaultColor = Color.black;
return Color;
})();
var Camera = (function () {
function Camera(pos, lookAt) {
this.pos = pos;
var down = new Vector(0.0, -1.0, 0.0);
this.forward = Vector.norm(Vector.minus(lookAt, this.pos));
this.right = Vector.times(1.5, Vector.norm(Vector.cross(this.forward, down)));
this.up = Vector.times(1.5, Vector.norm(Vector.cross(this.forward, this.right)));
}
return Camera;
})();
var Sphere = (function () {
function Sphere(center, radius, surface) {
this.center = center;
this.surface = surface;
this.radius2 = radius * radius;
}
Sphere.prototype.normal = function (pos) {
return Vector.norm(Vector.minus(pos, this.center));
};
Sphere.prototype.intersect = function (ray) {
var eo = Vector.minus(this.center, ray.start);
var v = Vector.dot(eo, ray.dir);
var dist = 0;
if (v >= 0) {
var disc = this.radius2 - (Vector.dot(eo, eo) - v * v);
if (disc >= 0) {
dist = v - Math.sqrt(disc);
}
}
if (dist === 0) {
return null;
} else {
return { thing: this, ray: ray, dist: dist };
}
};
return Sphere;
})();
var Plane = (function () {
function Plane(norm, offset, surface) {
this.surface = surface;
this.normal = function (pos) {
return norm;
};
this.intersect = function (ray) {
var denom = Vector.dot(norm, ray.dir);
if (denom > 0) {
return null;
} else {
var dist = (Vector.dot(norm, ray.start) + offset) / (-denom);
return { thing: this, ray: ray, dist: dist };
}
};
}
return Plane;
})();
var Surfaces;
(function (Surfaces) {
Surfaces.shiny = {
diffuse: function (pos) {
return Color.white;
},
specular: function (pos) {
return Color.grey;
},
reflect: function (pos) {
return 0.7;
},
roughness: 250
};
Surfaces.checkerboard = {
diffuse: function (pos) {
if ((Math.floor(pos.z) + Math.floor(pos.x)) % 2 !== 0) {
return Color.white;
} else {
return Color.black;
}
},
specular: function (pos) {
return Color.white;
},
reflect: function (pos) {
if ((Math.floor(pos.z) + Math.floor(pos.x)) % 2 !== 0) {
return 0.1;
} else {
return 0.7;
}
},
roughness: 150
};
})(Surfaces || (Surfaces = {}));
var RayTracer = (function () {
function RayTracer() {
this.maxDepth = 5;
}
RayTracer.prototype.intersections = function (ray, scene) {
var closest = +Infinity;
var closestInter = undefined;
for (var i in scene.things) {
var inter = scene.things[i].intersect(ray);
if (inter != null && inter.dist < closest) {
closestInter = inter;
closest = inter.dist;
}
}
return closestInter;
};
RayTracer.prototype.testRay = function (ray, scene) {
var isect = this.intersections(ray, scene);
if (isect != null) {
return isect.dist;
} else {
return undefined;
}
};
RayTracer.prototype.traceRay = function (ray, scene, depth) {
var isect = this.intersections(ray, scene);
if (isect === undefined) {
return Color.background;
} else {
return this.shade(isect, scene, depth);
}
};
RayTracer.prototype.shade = function (isect, scene, depth) {
var d = isect.ray.dir;
var pos = Vector.plus(Vector.times(isect.dist, d), isect.ray.start);
var normal = isect.thing.normal(pos);
var reflectDir = Vector.minus(d, Vector.times(2, Vector.times(Vector.dot(normal, d), normal)));
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);
};
RayTracer.prototype.getReflectionColor = function (thing, pos, normal, rd, scene, depth) {
return Color.scale(thing.surface.reflect(pos), this.traceRay({ start: pos, dir: rd }, scene, depth + 1));
};
RayTracer.prototype.getNaturalColor = function (thing, pos, norm, rd, scene) {
var _this = this;
var addLight = function (col, light) {
var ldis = Vector.minus(light.pos, pos);
var livec = Vector.norm(ldis);
var neatIsect = _this.testRay({ start: pos, dir: livec }, scene);
var isInShadow = (neatIsect === undefined) ? false : (neatIsect <= Vector.mag(ldis));
if (isInShadow) {
return col;
} else {
var illum = Vector.dot(livec, norm);
var lcolor = (illum > 0) ? Color.scale(illum, light.color) : Color.defaultColor;
var specular = Vector.dot(livec, Vector.norm(rd));
var scolor = (specular > 0) ? Color.scale(Math.pow(specular, thing.surface.roughness), light.color) : Color.defaultColor;
return Color.plus(col, Color.plus(Color.times(thing.surface.diffuse(pos), lcolor), Color.times(thing.surface.specular(pos), scolor)));
}
};
return scene.lights.reduce(addLight, Color.defaultColor);
};
RayTracer.prototype.render = function (scene, ctx, screenWidth, screenHeight) {
var getPoint = function (x, y, camera) {
var recenterX = function (x) {
return (x - (screenWidth / 2.0)) / 2.0 / screenWidth;
};
var recenterY = function (y) {
return -(y - (screenHeight / 2.0)) / 2.0 / screenHeight;
};
return Vector.norm(Vector.plus(camera.forward, Vector.plus(Vector.times(recenterX(x), camera.right), Vector.times(recenterY(y), camera.up))));
};
for (var y = 0; y < screenHeight; y++) {
for (var x = 0; x < screenWidth; x++) {
var color = this.traceRay({ start: scene.camera.pos, dir: getPoint(x, y, scene.camera) }, scene, 0);
var c = Color.toDrawingColor(color);
ctx.fillStyle = "rgb(" + String(c.r) + ", " + String(c.g) + ", " + String(c.b) + ")";
ctx.fillRect(x, y, x + 1, y + 1);
}
}
};
return RayTracer;
})();
function defaultScene() {
return {
things: [
new Plane(new Vector(0.0, 1.0, 0.0), 0.0, Surfaces.checkerboard),
new Sphere(new Vector(0.0, 1.0, -0.25), 1.0, Surfaces.shiny),
new Sphere(new Vector(-1.0, 0.5, 1.5), 0.5, Surfaces.shiny)
],
lights: [
{ pos: new Vector(-2.0, 2.5, 0.0), color: new Color(0.49, 0.07, 0.07) },
{ pos: new Vector(1.5, 2.5, 1.5), color: new Color(0.07, 0.07, 0.49) },
{ pos: new Vector(1.5, 2.5, -1.5), color: new Color(0.07, 0.49, 0.071) },
{ pos: new Vector(0.0, 3.5, 0.0), color: new Color(0.21, 0.21, 0.35) }
],
camera: new Camera(new Vector(3.0, 2.0, 4.0), new Vector(-1.0, 0.5, 0.0))
};
}
function exec() {
var canv = document.createElement("canvas");
canv.width = 256;
canv.height = 256;
document.body.appendChild(canv);
var ctx = canv.getContext("2d");
var rayTracer = new RayTracer();
return rayTracer.render(defaultScene(), ctx, 256, 256);
}
exec();
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment