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| 1 | +class Vector { |
| 2 | + |
| 3 | + constructor(public x: number, public y: number, public z: number) { } |
| 4 | + |
| 5 | + static times(k: number, v: Vector) { |
| 6 | + return new Vector(k * v.x, k * v.y, k * v.z); |
| 7 | + } |
| 8 | + |
| 9 | + static minus(v1: Vector, v2: Vector) { |
| 10 | + return new Vector(v1.x - v2.x, v1.y - v2.y, v1.z - v2.z); |
| 11 | + } |
| 12 | + |
| 13 | + static plus(v1: Vector, v2: Vector) { |
| 14 | + return new Vector(v1.x + v2.x, v1.y + v2.y, v1.z + v2.z); |
| 15 | + } |
| 16 | + |
| 17 | + static dot(v1: Vector, v2: Vector) { |
| 18 | + return v1.x * v2.x + v1.y * v2.y + v1.z * v2.z; |
| 19 | + } |
| 20 | + |
| 21 | + static mag(v: Vector) { |
| 22 | + return Math.sqrt(v.x * v.x + v.y * v.y + v.z * v.z); |
| 23 | + } |
| 24 | + |
| 25 | + static norm(v: Vector) { |
| 26 | + var mag = Vector.mag(v); |
| 27 | + var div = (mag === 0) ? Infinity : 1.0 / mag; |
| 28 | + return Vector.times(div, v); |
| 29 | + } |
| 30 | + |
| 31 | + static cross(v1: Vector, v2: Vector) { |
| 32 | + return new Vector(v1.y * v2.z - v1.z * v2.y, |
| 33 | + v1.z * v2.x - v1.x * v2.z, |
| 34 | + v1.x * v2.y - v1.y * v2.x); |
| 35 | + } |
| 36 | + |
| 37 | +} |
| 38 | + |
| 39 | +class Color { |
| 40 | + |
| 41 | + constructor(public r: number, public g: number, public b: number) { } |
| 42 | + |
| 43 | + static scale(k: number, v: Color) { |
| 44 | + return new Color(k * v.r, k * v.g, k * v.b); |
| 45 | + } |
| 46 | + |
| 47 | + static plus(v1: Color, v2: Color) { |
| 48 | + return new Color(v1.r + v2.r, v1.g + v2.g, v1.b + v2.b); |
| 49 | + } |
| 50 | + |
| 51 | + static times(v1: Color, v2: Color) { |
| 52 | + return new Color(v1.r * v2.r, v1.g * v2.g, v1.b * v2.b); |
| 53 | + } |
| 54 | + |
| 55 | + static white = new Color(1.0, 1.0, 1.0); |
| 56 | + static grey = new Color(0.5, 0.5, 0.5); |
| 57 | + static black = new Color(0.0, 0.0, 0.0); |
| 58 | + static background = Color.black; |
| 59 | + static defaultColor = Color.black; |
| 60 | + |
| 61 | + static toDrawingColor(c: Color) { |
| 62 | + var legalize = d => d > 1 ? 1 : d; |
| 63 | + return { |
| 64 | + r: Math.floor(legalize(c.r) * 255), |
| 65 | + g: Math.floor(legalize(c.g) * 255), |
| 66 | + b: Math.floor(legalize(c.b) * 255) |
| 67 | + } |
| 68 | + } |
| 69 | + |
| 70 | +} |
| 71 | + |
| 72 | +class Camera { |
| 73 | + |
| 74 | + forward: Vector; |
| 75 | + right: Vector; |
| 76 | + up: Vector; |
| 77 | + |
| 78 | + constructor(public pos: Vector, lookAt: Vector) { |
| 79 | + var down = new Vector(0.0, -1.0, 0.0); |
| 80 | + this.forward = Vector.norm(Vector.minus(lookAt, this.pos)); |
| 81 | + this.right = Vector.times(1.5, Vector.norm(Vector.cross(this.forward, down))); |
| 82 | + this.up = Vector.times(1.5, Vector.norm(Vector.cross(this.forward, this.right))); |
| 83 | + } |
| 84 | + |
| 85 | +} |
| 86 | + |
| 87 | +interface Ray { |
| 88 | + start: Vector; |
| 89 | + dir: Vector; |
| 90 | +} |
| 91 | + |
| 92 | +interface Intersection { |
| 93 | + thing: Thing; |
| 94 | + ray: Ray; |
| 95 | + dist: number; |
| 96 | +} |
| 97 | + |
| 98 | +interface Surface { |
| 99 | + diffuse: (pos: Vector) => Color; |
| 100 | + specular: (pos: Vector) => Color; |
| 101 | + reflect: (pos: Vector) => number; |
| 102 | + roughness: number; |
| 103 | +} |
| 104 | + |
| 105 | +interface Thing { |
| 106 | + intersect: (ray: Ray) => Intersection; |
| 107 | + normal: (pos: Vector) => Vector; |
| 108 | + surface: Surface; |
| 109 | +} |
| 110 | + |
| 111 | +interface Light { |
| 112 | + pos: Vector; |
| 113 | + color: Color; |
| 114 | +} |
| 115 | + |
| 116 | +interface Scene { |
| 117 | + things: Thing[]; |
| 118 | + lights: Light[]; |
| 119 | + camera: Camera; |
| 120 | +} |
| 121 | + |
| 122 | +class Sphere implements Thing { |
| 123 | + |
| 124 | + radius2: number; |
| 125 | + |
| 126 | + constructor(public center: Vector, radius: number, public surface: Surface) { |
| 127 | + this.radius2 = radius * radius; |
| 128 | + } |
| 129 | + |
| 130 | + normal(pos: Vector): Vector { |
| 131 | + return Vector.norm(Vector.minus(pos, this.center)); |
| 132 | + } |
| 133 | + |
| 134 | + intersect(ray: Ray) { |
| 135 | + var eo = Vector.minus(this.center, ray.start); |
| 136 | + var v = Vector.dot(eo, ray.dir); |
| 137 | + var dist = 0; |
| 138 | + if (v >= 0) { |
| 139 | + var disc = this.radius2 - (Vector.dot(eo, eo) - v * v); |
| 140 | + if (disc >= 0) { |
| 141 | + dist = v - Math.sqrt(disc); |
| 142 | + } |
| 143 | + } |
| 144 | + if (dist === 0) { |
| 145 | + return null; |
| 146 | + } else { |
| 147 | + return { thing: this, ray: ray, dist: dist }; |
| 148 | + } |
| 149 | + } |
| 150 | + |
| 151 | +} |
| 152 | + |
| 153 | +class Plane implements Thing { |
| 154 | + |
| 155 | + normal: (pos: Vector) => Vector; |
| 156 | + intersect: (ray: Ray) => Intersection; |
| 157 | + |
| 158 | + constructor(norm: Vector, offset: number, public surface: Surface) { |
| 159 | + this.normal = function(pos: Vector) { return norm; } |
| 160 | + this.intersect = function(ray: Ray): Intersection { |
| 161 | + var denom = Vector.dot(norm, ray.dir); |
| 162 | + if (denom > 0) { |
| 163 | + return null; |
| 164 | + } else { |
| 165 | + var dist = (Vector.dot(norm, ray.start) + offset) / (-denom); |
| 166 | + return { thing: this, ray: ray, dist: dist }; |
| 167 | + } |
| 168 | + } |
| 169 | + } |
| 170 | + |
| 171 | +} |
| 172 | + |
| 173 | +module Surfaces { |
| 174 | + |
| 175 | + export var shiny: Surface = { |
| 176 | + diffuse: function(pos) { return Color.white; }, |
| 177 | + specular: function(pos) { return Color.grey; }, |
| 178 | + reflect: function(pos) { return 0.7; }, |
| 179 | + roughness: 250 |
| 180 | + } |
| 181 | + |
| 182 | + export var checkerboard: Surface = { |
| 183 | + diffuse: function(pos) { |
| 184 | + if ((Math.floor(pos.z) + Math.floor(pos.x)) % 2 !== 0) { |
| 185 | + return Color.white; |
| 186 | + } else { |
| 187 | + return Color.black; |
| 188 | + } |
| 189 | + }, |
| 190 | + specular: function(pos) { return Color.white; }, |
| 191 | + reflect: function(pos) { |
| 192 | + if ((Math.floor(pos.z) + Math.floor(pos.x)) % 2 !== 0) { |
| 193 | + return 0.1; |
| 194 | + } else { |
| 195 | + return 0.7; |
| 196 | + } |
| 197 | + }, |
| 198 | + roughness: 150 |
| 199 | + } |
| 200 | + |
| 201 | +} |
| 202 | + |
| 203 | + |
| 204 | +class RayTracer { |
| 205 | + |
| 206 | + private maxDepth = 5; |
| 207 | + |
| 208 | + private intersections(ray: Ray, scene: Scene) { |
| 209 | + var closest = +Infinity; |
| 210 | + var closestInter: Intersection = undefined; |
| 211 | + for (var i in scene.things) { |
| 212 | + var inter = scene.things[i].intersect(ray); |
| 213 | + if (inter != null && inter.dist < closest) { |
| 214 | + closestInter = inter; |
| 215 | + closest = inter.dist; |
| 216 | + } |
| 217 | + } |
| 218 | + return closestInter; |
| 219 | + } |
| 220 | + |
| 221 | + private testRay(ray: Ray, scene: Scene) { |
| 222 | + var isect = this.intersections(ray, scene); |
| 223 | + if (isect != null) { |
| 224 | + return isect.dist; |
| 225 | + } else { |
| 226 | + return undefined; |
| 227 | + } |
| 228 | + } |
| 229 | + |
| 230 | + private traceRay(ray: Ray, scene: Scene, depth: number): Color { |
| 231 | + var isect = this.intersections(ray, scene); |
| 232 | + if (isect === undefined) { |
| 233 | + return Color.background; |
| 234 | + } else { |
| 235 | + return this.shade(isect, scene, depth); |
| 236 | + } |
| 237 | + } |
| 238 | + |
| 239 | + private shade(isect: Intersection, scene: Scene, depth: number) { |
| 240 | + var d = isect.ray.dir; |
| 241 | + var pos = Vector.plus(Vector.times(isect.dist, d), isect.ray.start); |
| 242 | + var normal = isect.thing.normal(pos); |
| 243 | + var reflectDir = Vector.minus(d, Vector.times(2, Vector.times(Vector.dot(normal, d), normal))); |
| 244 | + var naturalColor = Color.plus(Color.background, |
| 245 | + this.getNaturalColor(isect.thing, pos, normal, reflectDir, scene)); |
| 246 | + var reflectedColor = (depth >= this.maxDepth) ? Color.grey : this.getReflectionColor(isect.thing, pos, normal, reflectDir, scene, depth); |
| 247 | + return Color.plus(naturalColor, reflectedColor); |
| 248 | + } |
| 249 | + |
| 250 | + private getReflectionColor(thing: Thing, pos: Vector, normal: Vector, rd: Vector, scene: Scene, depth: number) { |
| 251 | + return Color.scale(thing.surface.reflect(pos), this.traceRay({ start: pos, dir: rd }, scene, depth + 1)); |
| 252 | + } |
| 253 | + |
| 254 | + private getNaturalColor(thing: Thing, pos: Vector, norm: Vector, rd: Vector, scene: Scene) { |
| 255 | + var addLight = (col, light) => { |
| 256 | + var ldis = Vector.minus(light.pos, pos); |
| 257 | + var livec = Vector.norm(ldis); |
| 258 | + var neatIsect = this.testRay({ start: pos, dir: livec }, scene); |
| 259 | + var isInShadow = (neatIsect === undefined) ? false : (neatIsect <= Vector.mag(ldis)); |
| 260 | + if (isInShadow) { |
| 261 | + return col; |
| 262 | + } else { |
| 263 | + var illum = Vector.dot(livec, norm); |
| 264 | + var lcolor = (illum > 0) ? Color.scale(illum, light.color) |
| 265 | + : Color.defaultColor; |
| 266 | + var specular = Vector.dot(livec, Vector.norm(rd)); |
| 267 | + var scolor = (specular > 0) ? Color.scale(Math.pow(specular, thing.surface.roughness), light.color) |
| 268 | + : Color.defaultColor; |
| 269 | + return Color.plus(col, Color.plus(Color.times(thing.surface.diffuse(pos), lcolor), |
| 270 | + Color.times(thing.surface.specular(pos), scolor))); |
| 271 | + } |
| 272 | + } |
| 273 | + return scene.lights.reduce(addLight, Color.defaultColor); |
| 274 | + } |
| 275 | + |
| 276 | + render(scene, ctx, screenWidth, screenHeight) { |
| 277 | + var getPoint = (x, y, camera) => { |
| 278 | + var recenterX = x => (x - (screenWidth / 2.0)) / 2.0 / screenWidth; |
| 279 | + var recenterY = y => -(y - (screenHeight / 2.0)) / 2.0 / screenHeight; |
| 280 | + return Vector.norm(Vector.plus(camera.forward, Vector.plus(Vector.times(recenterX(x), camera.right), Vector.times(recenterY(y), camera.up)))); |
| 281 | + } |
| 282 | + for (var y = 0; y < screenHeight; y++) { |
| 283 | + for (var x = 0; x < screenWidth; x++) { |
| 284 | + var color = this.traceRay({ start: scene.camera.pos, dir: getPoint(x, y, scene.camera) }, scene, 0); |
| 285 | + var c = Color.toDrawingColor(color); |
| 286 | + ctx.fillStyle = "rgb(" + String(c.r) + ", " + String(c.g) + ", " + String(c.b) + ")"; |
| 287 | + ctx.fillRect(x, y, x + 1, y + 1); |
| 288 | + } |
| 289 | + } |
| 290 | + } |
| 291 | + |
| 292 | +} |
| 293 | + |
| 294 | + |
| 295 | +function defaultScene(): Scene { |
| 296 | + return { |
| 297 | + things: [new Plane(new Vector(0.0, 1.0, 0.0), 0.0, Surfaces.checkerboard), |
| 298 | + new Sphere(new Vector(0.0, 1.0, -0.25), 1.0, Surfaces.shiny), |
| 299 | + new Sphere(new Vector(-1.0, 0.5, 1.5), 0.5, Surfaces.shiny)], |
| 300 | + lights: [{ pos: new Vector(-2.0, 2.5, 0.0), color: new Color(0.49, 0.07, 0.07) }, |
| 301 | + { pos: new Vector(1.5, 2.5, 1.5), color: new Color(0.07, 0.07, 0.49) }, |
| 302 | + { pos: new Vector(1.5, 2.5, -1.5), color: new Color(0.07, 0.49, 0.071) }, |
| 303 | + { pos: new Vector(0.0, 3.5, 0.0), color: new Color(0.21, 0.21, 0.35) }], |
| 304 | + camera: new Camera(new Vector(3.0, 2.0, 4.0), new Vector(-1.0, 0.5, 0.0)) |
| 305 | + }; |
| 306 | +} |
| 307 | + |
| 308 | +function exec() { |
| 309 | + var canv = document.createElement("canvas"); |
| 310 | + canv.width = 256; |
| 311 | + canv.height = 256; |
| 312 | + document.body.appendChild(canv); |
| 313 | + var ctx = canv.getContext("2d"); |
| 314 | + var rayTracer = new RayTracer(); |
| 315 | + return rayTracer.render(defaultScene(), ctx, 256, 256); |
| 316 | +} |
| 317 | + |
| 318 | +exec(); |
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