1/*
2 * Copyright (C) 2007 Apple Inc.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26function createVector(x,y,z) {
27    return new Array(x,y,z);
28}
29
30function sqrLengthVector(self) {
31    return self[0] * self[0] + self[1] * self[1] + self[2] * self[2];
32}
33
34function lengthVector(self) {
35    return Math.sqrt(self[0] * self[0] + self[1] * self[1] + self[2] * self[2]);
36}
37
38function addVector(self, v) {
39    self[0] += v[0];
40    self[1] += v[1];
41    self[2] += v[2];
42    return self;
43}
44
45function subVector(self, v) {
46    self[0] -= v[0];
47    self[1] -= v[1];
48    self[2] -= v[2];
49    return self;
50}
51
52function scaleVector(self, scale) {
53    self[0] *= scale;
54    self[1] *= scale;
55    self[2] *= scale;
56    return self;
57}
58
59function normaliseVector(self) {
60    var len = Math.sqrt(self[0] * self[0] + self[1] * self[1] + self[2] * self[2]);
61    self[0] /= len;
62    self[1] /= len;
63    self[2] /= len;
64    return self;
65}
66
67function add(v1, v2) {
68    return new Array(v1[0] + v2[0], v1[1] + v2[1], v1[2] + v2[2]);
69}
70
71function sub(v1, v2) {
72    return new Array(v1[0] - v2[0], v1[1] - v2[1], v1[2] - v2[2]);
73}
74
75function scalev(v1, v2) {
76    return new Array(v1[0] * v2[0], v1[1] * v2[1], v1[2] * v2[2]);
77}
78
79function dot(v1, v2) {
80    return v1[0] * v2[0] + v1[1] * v2[1] + v1[2] * v2[2];
81}
82
83function scale(v, scale) {
84    return [v[0] * scale, v[1] * scale, v[2] * scale];
85}
86
87function cross(v1, v2) {
88    return [v1[1] * v2[2] - v1[2] * v2[1],
89            v1[2] * v2[0] - v1[0] * v2[2],
90            v1[0] * v2[1] - v1[1] * v2[0]];
91
92}
93
94function normalise(v) {
95    var len = lengthVector(v);
96    return [v[0] / len, v[1] / len, v[2] / len];
97}
98
99function transformMatrix(self, v) {
100    var vals = self;
101    var x  = vals[0] * v[0] + vals[1] * v[1] + vals[2] * v[2] + vals[3];
102    var y  = vals[4] * v[0] + vals[5] * v[1] + vals[6] * v[2] + vals[7];
103    var z  = vals[8] * v[0] + vals[9] * v[1] + vals[10] * v[2] + vals[11];
104    return [x, y, z];
105}
106
107function invertMatrix(self) {
108    var temp = new Array(16);
109    var tx = -self[3];
110    var ty = -self[7];
111    var tz = -self[11];
112    for (h = 0; h < 3; h++)
113        for (v = 0; v < 3; v++)
114            temp[h + v * 4] = self[v + h * 4];
115    for (i = 0; i < 11; i++)
116        self[i] = temp[i];
117    self[3] = tx * self[0] + ty * self[1] + tz * self[2];
118    self[7] = tx * self[4] + ty * self[5] + tz * self[6];
119    self[11] = tx * self[8] + ty * self[9] + tz * self[10];
120    return self;
121}
122
123
124// Triangle intersection using barycentric coord method
125function Triangle(p1, p2, p3) {
126    var edge1 = sub(p3, p1);
127    var edge2 = sub(p2, p1);
128    var normal = cross(edge1, edge2);
129    if (Math.abs(normal[0]) > Math.abs(normal[1]))
130        if (Math.abs(normal[0]) > Math.abs(normal[2]))
131            this.axis = 0;
132        else
133            this.axis = 2;
134    else
135        if (Math.abs(normal[1]) > Math.abs(normal[2]))
136            this.axis = 1;
137        else
138            this.axis = 2;
139    var u = (this.axis + 1) % 3;
140    var v = (this.axis + 2) % 3;
141    var u1 = edge1[u];
142    var v1 = edge1[v];
143
144    var u2 = edge2[u];
145    var v2 = edge2[v];
146    this.normal = normalise(normal);
147    this.nu = normal[u] / normal[this.axis];
148    this.nv = normal[v] / normal[this.axis];
149    this.nd = dot(normal, p1) / normal[this.axis];
150    var det = u1 * v2 - v1 * u2;
151    this.eu = p1[u];
152    this.ev = p1[v];
153    this.nu1 = u1 / det;
154    this.nv1 = -v1 / det;
155    this.nu2 = v2 / det;
156    this.nv2 = -u2 / det;
157    this.material = [0.7, 0.7, 0.7];
158}
159
160Triangle.prototype.intersect = function(orig, dir, near, far) {
161    var u = (this.axis + 1) % 3;
162    var v = (this.axis + 2) % 3;
163    var d = dir[this.axis] + this.nu * dir[u] + this.nv * dir[v];
164    var t = (this.nd - orig[this.axis] - this.nu * orig[u] - this.nv * orig[v]) / d;
165    if (t < near || t > far)
166        return null;
167    var Pu = orig[u] + t * dir[u] - this.eu;
168    var Pv = orig[v] + t * dir[v] - this.ev;
169    var a2 = Pv * this.nu1 + Pu * this.nv1;
170    if (a2 < 0)
171        return null;
172    var a3 = Pu * this.nu2 + Pv * this.nv2;
173    if (a3 < 0)
174        return null;
175
176    if ((a2 + a3) > 1)
177        return null;
178    return t;
179}
180
181function Scene(a_triangles) {
182    this.triangles = a_triangles;
183    this.lights = [];
184    this.ambient = [0,0,0];
185    this.background = [0.8,0.8,1];
186}
187var zero = new Array(0,0,0);
188
189Scene.prototype.intersect = function(origin, dir, near, far) {
190    var closest = null;
191    for (i = 0; i < this.triangles.length; i++) {
192        var triangle = this.triangles[i];
193        var d = triangle.intersect(origin, dir, near, far);
194        if (d == null || d > far || d < near)
195            continue;
196        far = d;
197        closest = triangle;
198    }
199
200    if (!closest)
201        return [this.background[0],this.background[1],this.background[2]];
202
203    var normal = closest.normal;
204    var hit = add(origin, scale(dir, far));
205    if (dot(dir, normal) > 0)
206        normal = [-normal[0], -normal[1], -normal[2]];
207
208    var colour = null;
209    if (closest.shader) {
210        colour = closest.shader(closest, hit, dir);
211    } else {
212        colour = closest.material;
213    }
214
215    // do reflection
216    var reflected = null;
217    if (colour.reflection > 0.001) {
218        var reflection = addVector(scale(normal, -2*dot(dir, normal)), dir);
219        reflected = this.intersect(hit, reflection, 0.0001, 1000000);
220        if (colour.reflection >= 0.999999)
221            return reflected;
222    }
223
224    var l = [this.ambient[0], this.ambient[1], this.ambient[2]];
225    for (var i = 0; i < this.lights.length; i++) {
226        var light = this.lights[i];
227        var toLight = sub(light, hit);
228        var distance = lengthVector(toLight);
229        scaleVector(toLight, 1.0/distance);
230        distance -= 0.0001;
231        if (this.blocked(hit, toLight, distance))
232            continue;
233        var nl = dot(normal, toLight);
234        if (nl > 0)
235            addVector(l, scale(light.colour, nl));
236    }
237    l = scalev(l, colour);
238    if (reflected) {
239        l = addVector(scaleVector(l, 1 - colour.reflection), scaleVector(reflected, colour.reflection));
240    }
241    return l;
242}
243
244Scene.prototype.blocked = function(O, D, far) {
245    var near = 0.0001;
246    var closest = null;
247    for (i = 0; i < this.triangles.length; i++) {
248        var triangle = this.triangles[i];
249        var d = triangle.intersect(O, D, near, far);
250        if (d == null || d > far || d < near)
251            continue;
252        return true;
253    }
254
255    return false;
256}
257
258
259// this camera code is from notes i made ages ago, it is from *somewhere* -- i cannot remember where
260// that somewhere is
261function Camera(origin, lookat, up) {
262    var zaxis = normaliseVector(subVector(lookat, origin));
263    var xaxis = normaliseVector(cross(up, zaxis));
264    var yaxis = normaliseVector(cross(xaxis, subVector([0,0,0], zaxis)));
265    var m = new Array(16);
266    m[0] = xaxis[0]; m[1] = xaxis[1]; m[2] = xaxis[2];
267    m[4] = yaxis[0]; m[5] = yaxis[1]; m[6] = yaxis[2];
268    m[8] = zaxis[0]; m[9] = zaxis[1]; m[10] = zaxis[2];
269    invertMatrix(m);
270    m[3] = 0; m[7] = 0; m[11] = 0;
271    this.origin = origin;
272    this.directions = new Array(4);
273    this.directions[0] = normalise([-0.7,  0.7, 1]);
274    this.directions[1] = normalise([ 0.7,  0.7, 1]);
275    this.directions[2] = normalise([ 0.7, -0.7, 1]);
276    this.directions[3] = normalise([-0.7, -0.7, 1]);
277    this.directions[0] = transformMatrix(m, this.directions[0]);
278    this.directions[1] = transformMatrix(m, this.directions[1]);
279    this.directions[2] = transformMatrix(m, this.directions[2]);
280    this.directions[3] = transformMatrix(m, this.directions[3]);
281}
282
283Camera.prototype.generateRayPair = function(y) {
284    rays = new Array(new Object(), new Object());
285    rays[0].origin = this.origin;
286    rays[1].origin = this.origin;
287    rays[0].dir = addVector(scale(this.directions[0], y), scale(this.directions[3], 1 - y));
288    rays[1].dir = addVector(scale(this.directions[1], y), scale(this.directions[2], 1 - y));
289    return rays;
290}
291
292function renderRows(camera, scene, pixels, width, height, starty, stopy) {
293    for (var y = starty; y < stopy; y++) {
294        var rays = camera.generateRayPair(y / height);
295        for (var x = 0; x < width; x++) {
296            var xp = x / width;
297            var origin = addVector(scale(rays[0].origin, xp), scale(rays[1].origin, 1 - xp));
298            var dir = normaliseVector(addVector(scale(rays[0].dir, xp), scale(rays[1].dir, 1 - xp)));
299            var l = scene.intersect(origin, dir);
300            pixels[y][x] = l;
301        }
302    }
303}
304
305Camera.prototype.render = function(scene, pixels, width, height) {
306    var cam = this;
307    var row = 0;
308    renderRows(cam, scene, pixels, width, height, 0, height);
309}
310
311
312
313function raytraceScene()
314{
315    var startDate = new Date().getTime();
316    var numTriangles = 2 * 6;
317    var triangles = new Array();//numTriangles);
318    var tfl = createVector(-10,  10, -10);
319    var tfr = createVector( 10,  10, -10);
320    var tbl = createVector(-10,  10,  10);
321    var tbr = createVector( 10,  10,  10);
322    var bfl = createVector(-10, -10, -10);
323    var bfr = createVector( 10, -10, -10);
324    var bbl = createVector(-10, -10,  10);
325    var bbr = createVector( 10, -10,  10);
326
327    // cube!!!
328    // front
329    var i = 0;
330
331    triangles[i++] = new Triangle(tfl, tfr, bfr);
332    triangles[i++] = new Triangle(tfl, bfr, bfl);
333    // back
334    triangles[i++] = new Triangle(tbl, tbr, bbr);
335    triangles[i++] = new Triangle(tbl, bbr, bbl);
336    //        triangles[i-1].material = [0.7,0.2,0.2];
337    //            triangles[i-1].material.reflection = 0.8;
338    // left
339    triangles[i++] = new Triangle(tbl, tfl, bbl);
340    //            triangles[i-1].reflection = 0.6;
341    triangles[i++] = new Triangle(tfl, bfl, bbl);
342    //            triangles[i-1].reflection = 0.6;
343    // right
344    triangles[i++] = new Triangle(tbr, tfr, bbr);
345    triangles[i++] = new Triangle(tfr, bfr, bbr);
346    // top
347    triangles[i++] = new Triangle(tbl, tbr, tfr);
348    triangles[i++] = new Triangle(tbl, tfr, tfl);
349    // bottom
350    triangles[i++] = new Triangle(bbl, bbr, bfr);
351    triangles[i++] = new Triangle(bbl, bfr, bfl);
352
353    //Floor!!!!
354    var green = createVector(0.0, 0.4, 0.0);
355    var grey = createVector(0.4, 0.4, 0.4);
356    grey.reflection = 1.0;
357    var floorShader = function(tri, pos, view) {
358        var x = ((pos[0]/32) % 2 + 2) % 2;
359        var z = ((pos[2]/32 + 0.3) % 2 + 2) % 2;
360        if (x < 1 != z < 1) {
361            //in the real world we use the fresnel term...
362            //    var angle = 1-dot(view, tri.normal);
363            //   angle *= angle;
364            //  angle *= angle;
365            // angle *= angle;
366            //grey.reflection = angle;
367            return grey;
368        } else
369            return green;
370    }
371    var ffl = createVector(-1000, -30, -1000);
372    var ffr = createVector( 1000, -30, -1000);
373    var fbl = createVector(-1000, -30,  1000);
374    var fbr = createVector( 1000, -30,  1000);
375    triangles[i++] = new Triangle(fbl, fbr, ffr);
376    triangles[i-1].shader = floorShader;
377    triangles[i++] = new Triangle(fbl, ffr, ffl);
378    triangles[i-1].shader = floorShader;
379
380    var _scene = new Scene(triangles);
381    _scene.lights[0] = createVector(20, 38, -22);
382    _scene.lights[0].colour = createVector(0.7, 0.3, 0.3);
383    _scene.lights[1] = createVector(-23, 40, 17);
384    _scene.lights[1].colour = createVector(0.7, 0.3, 0.3);
385    _scene.lights[2] = createVector(23, 20, 17);
386    _scene.lights[2].colour = createVector(0.7, 0.7, 0.7);
387    _scene.ambient = createVector(0.1, 0.1, 0.1);
388    //  _scene.background = createVector(0.7, 0.7, 1.0);
389
390    var size = 30;
391    var pixels = new Array();
392    for (var y = 0; y < size; y++) {
393        pixels[y] = new Array();
394        for (var x = 0; x < size; x++) {
395            pixels[y][x] = 0;
396        }
397    }
398
399    var _camera = new Camera(createVector(-40, 40, 40), createVector(0, 0, 0), createVector(0, 1, 0));
400    _camera.render(_scene, pixels, size, size);
401
402    return pixels;
403}
404
405function arrayToCanvasCommands(pixels)
406{
407    var s = '<canvas id="renderCanvas" width="30px" height="30px"></canvas><scr' + 'ipt>\nvar pixels = [';
408    var size = 30;
409    for (var y = 0; y < size; y++) {
410        s += "[";
411        for (var x = 0; x < size; x++) {
412            s += "[" + pixels[y][x] + "],";
413        }
414        s+= "],";
415    }
416    s += '];\n    var canvas = document.getElementById("renderCanvas").getContext("2d");\n\
417\n\
418\n\
419    var size = 30;\n\
420    canvas.fillStyle = "red";\n\
421    canvas.fillRect(0, 0, size, size);\n\
422    canvas.scale(1, -1);\n\
423    canvas.translate(0, -size);\n\
424\n\
425    if (!canvas.setFillColor)\n\
426        canvas.setFillColor = function(r, g, b, a) {\n\
427            this.fillStyle = "rgb("+[Math.floor(r * 255), Math.floor(g * 255), Math.floor(b * 255)]+")";\n\
428    }\n\
429\n\
430for (var y = 0; y < size; y++) {\n\
431  for (var x = 0; x < size; x++) {\n\
432    var l = pixels[y][x];\n\
433    canvas.setFillColor(l[0], l[1], l[2], 1);\n\
434    canvas.fillRect(x, y, 1, 1);\n\
435  }\n\
436}</scr' + 'ipt>';
437
438    return s;
439}
440
441testOutput = arrayToCanvasCommands(raytraceScene());
442