/*
* Copyright (C) 2007 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of sourcecode must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE COMPUTER, INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
function createVector(x,y,z) {
return new Array(x,y,z);
}
function normalise(v) { var len = lengthVector(v);
return [v[0] / len, v[1] / len, v[2] / len];
}
function transformMatrix(self, v) { var vals = self; var x = vals[0] * v[0] + vals[1] * v[1] + vals[2] * v[2] + vals[3]; var y = vals[4] * v[0] + vals[5] * v[1] + vals[6] * v[2] + vals[7]; var z = vals[8] * v[0] + vals[9] * v[1] + vals[10] * v[2] + vals[11];
return [x, y, z];
}
function invertMatrix(self) { var temp = new Array(16); var tx = -self[3]; var ty = -self[7]; var tz = -self[11];
for (h = 0; h < 3; h++)
for (v = 0; v < 3; v++)
temp[h + v * 4] = self[v + h * 4];
for (i = 0; i < 11; i++)
self[i] = temp[i];
self[3] = tx * self[0] + ty * self[1] + tz * self[2];
self[7] = tx * self[4] + ty * self[5] + tz * self[6];
self[11] = tx * self[8] + ty * self[9] + tz * self[10];
return self;
}
// Triangle intersection using barycentric coord method
function Triangle(p1, p2, p3) { var edge1 = sub(p3, p1); var edge2 = sub(p2, p1); var normal = cross(edge1, edge2);
if (Math.abs(normal[0]) > Math.abs(normal[1]))
if (Math.abs(normal[0]) > Math.abs(normal[2]))
this.axis = 0;
else
this.axis = 2;
else
if (Math.abs(normal[1]) > Math.abs(normal[2]))
this.axis = 1;
else
this.axis = 2; varu = (this.axis + 1) % 3; var v = (this.axis + 2) % 3; var u1 = edge1[u]; var v1 = edge1[v];
Triangle.prototype.intersect = function(orig, dir, near, far) { varu = (this.axis + 1) % 3; var v = (this.axis + 2) % 3; var d = dir[this.axis] + this.nu * dir[u] + this.nv * dir[v]; var t = (this.nd - orig[this.axis] - this.nu * orig[u] - this.nv * orig[v]) / d;
if (t < near || t > far)
return null; var Pu = orig[u] + t * dir[u] - this.eu; var Pv = orig[v] + t * dir[v] - this.ev; var a2 = Pv * this.nu1 + Pu * this.nv1;
if (a2 < 0)
return null; var a3 = Pu * this.nu2 + Pv * this.nv2;
if (a3 < 0)
return null;
if ((a2 + a3) > 1)
return null;
return t;
}
function Scene(a_triangles) {
this.triangles = a_triangles;
this.lights = [];
this.ambient = [0,0,0];
this.background = [0.8,0.8,1];
} var zero = new Array(0,0,0);
Scene.prototype.intersect = function(origin, dir, near, far) { var closest = null;
for (i = 0; i < this.triangles.length; i++) { var triangle = this.triangles[i]; var d = triangle.intersect(origin, dir, near, far);
if (d == null || d > far || d < near)
continue;
far = d;
closest = triangle;
}
if (!closest)
return [this.background[0],this.background[1],this.background[2]];
var normal = closest.normal; var hit = add(origin, scale(dir, far));
if (dot(dir, normal) > 0)
normal = [-normal[0], -normal[1], -normal[2]];
var colour = null;
if (closest.shader) {
colour = closest.shader(closest, hit, dir);
} else {
colour = closest.material;
}
// do reflection var reflected = null;
if (colour.reflection > 0.001) { var reflection = addVector(scale(normal, -2*dot(dir, normal)), dir);
reflected = this.intersect(hit, reflection, 0.0001, 1000000);
if (colour.reflection >= 0.999999)
return reflected;
}
var l = [this.ambient[0], this.ambient[1], this.ambient[2]];
for (vari = 0; i < this.lights.length; i++) { var light = this.lights[i]; var toLight = sub(light, hit); var distance = lengthVector(toLight);
scaleVector(toLight, 1.0/distance);
distance -= 0.0001;
if (this.blocked(hit, toLight, distance))
continue; var nl = dot(normal, toLight);
if (nl > 0)
addVector(l, scale(light.colour, nl));
}
l = scalev(l, colour);
if (reflected) {
l = addVector(scaleVector(l, 1 - colour.reflection), scaleVector(reflected, colour.reflection));
}
return l;
}
Scene.prototype.blocked = function(O, D, far) { var near = 0.0001; var closest = null;
for (i = 0; i < this.triangles.length; i++) { var triangle = this.triangles[i]; var d = triangle.intersect(O, D, near, far);
if (d == null || d > far || d < near)
continue;
return true;
}
return false;
}
// this camera code is from notes i made ages ago, it is from *somewhere* -- i cannot remember where
// that somewhere is
function Camera(origin, lookat, up) { var zaxis = normaliseVector(subVector(lookat, origin)); var xaxis = normaliseVector(cross(up, zaxis)); var yaxis = normaliseVector(cross(xaxis, subVector([0,0,0], zaxis))); var m = new Array(16);
m[0] = xaxis[0]; m[1] = xaxis[1]; m[2] = xaxis[2];
m[4] = yaxis[0]; m[5] = yaxis[1]; m[6] = yaxis[2];
m[8] = zaxis[0]; m[9] = zaxis[1]; m[10] = zaxis[2];
invertMatrix(m);
m[3] = 0; m[7] = 0; m[11] = 0;
this.origin = origin;
this.directions = new Array(4);
this.directions[0] = normalise([-0.7, 0.7, 1]);
this.directions[1] = normalise([ 0.7, 0.7, 1]);
this.directions[2] = normalise([ 0.7, -0.7, 1]);
this.directions[3] = normalise([-0.7, -0.7, 1]);
this.directions[0] = transformMatrix(m, this.directions[0]);
this.directions[1] = transformMatrix(m, this.directions[1]);
this.directions[2] = transformMatrix(m, this.directions[2]);
this.directions[3] = transformMatrix(m, this.directions[3]);
}
function renderRows(camera, scene, pixels, width, height, starty, stopy) {
for (var y = starty; y < stopy; y++) { var rays = camera.generateRayPair(y / height);
for (var x = 0; x < width; x++) { var xp = x / width; var origin = addVector(scale(rays[0].origin, xp), scale(rays[1].origin, 1 - xp)); vardir = normaliseVector(addVector(scale(rays[0].dir, xp), scale(rays[1].dir, 1 - xp))); var l = scene.intersect(origin, dir);
pixels[y][x] = l;
}
}
}
var size = 30; var pixels = new Array();
for (var y = 0; y < size; y++) {
pixels[y] = new Array();
for (var x = 0; x < size; x++) {
pixels[y][x] = 0;
}
}
var _camera = new Camera(createVector(-40, 40, 40), createVector(0, 0, 0), createVector(0, 1, 0));
_camera.render(_scene, pixels, size, size);
return pixels;
}
function arrayToCanvasCommands(pixels)
{ vars = '<canvas id="renderCanvas" width="30px" height="30px"></canvas><scr' + 'ipt>\nvar pixels = ['; var size = 30;
for (var y = 0; y < size; y++) { s += "[";
for (var x = 0; x < size; x++) { s += "[" + pixels[y][x] + "],";
} s+= "],";
} s += '];\n var canvas = document.getElementById("renderCanvas").getContext("2d");\n\
\n\
\n\ var size = 30;\n\ canvas.fillStyle = "red";\n\ canvas.fillRect(0, 0, size, size);\n\ canvas.scale(1, -1);\n\ canvas.translate(0, -size);\n\
\n\
if (!canvas.setFillColor)\n\ canvas.setFillColor = function(r, g, b, a) {\n\
this.fillStyle = "rgb("+[Math.floor(r * 255), Math.floor(g * 255), Math.floor(b * 255)]+")";\n\
}\n\
\n\
for (var y = 0; y < size; y++) {\n\
for (var x = 0; x < size; x++) {\n\ var l = pixels[y][x];\n\ canvas.setFillColor(l[0], l[1], l[2], 1);\n\ canvas.fillRect(x, y, 1, 1);\n\
}\n\
}</scr' + 'ipt>';
Die Informationen auf dieser Webseite wurden
nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit,
noch Qualität der bereit gestellten Informationen zugesichert.
Bemerkung:
Die farbliche Syntaxdarstellung und die Messung sind noch experimentell.