ExplorerCanvas Example 1
/*
ExplorerCanvas
Copyright 2006 Google Inc.
-------------------------------------------------------------------------------
DESCRIPTION
Firefox, Safari and Opera 9 support the canvas tag to allow 2D command-based
drawing operations. ExplorerCanvas brings the same functionality to Internet
Explorer; web developers only need to include a single script tag in their
existing canvas webpages to enable this support.
Google Open Source:
Developers:
Emil A Eklund
Erik Arvidsson
Glen Murphy
*/
// Copyright 2006 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Known Issues:
//
// * Patterns are not implemented.
// * Radial gradient are not implemented. The VML version of these look very
// different from the canvas one.
// * Clipping paths are not implemented.
// * Coordsize. The width and height attribute have higher priority than the
// width and height style values which isn't correct.
// * Painting mode isn't implemented.
// * Canvas width/height should is using content-box by default. IE in
// Quirks mode will draw the canvas using border-box. Either change your
// doctype to HTML5
// (http://www.whatwg.org/specs/web-apps/current-work/#the-doctype)
// or use Box Sizing Behavior from WebFX
// (http://webfx.eae.net/dhtml/boxsizing/boxsizing.html)
// * Optimize. There is always room for speed improvements.
// only add this code if we do not already have a canvas implementation
if (!window.CanvasRenderingContext2D) {
(function () {
// alias some functions to make (compiled) code shorter
var m = Math;
var mr = m.round;
var ms = m.sin;
var mc = m.cos;
// this is used for sub pixel precision
var Z = 10;
var Z2 = Z / 2;
var G_vmlCanvasManager_ = {
init: function (opt_doc) {
var doc = opt_doc || document;
if (/MSIE/.test(navigator.userAgent) && !window.opera) {
var self = this;
doc.attachEvent("onreadystatechange", function () {
self.init_(doc);
});
}
},
init_: function (doc) {
if (doc.readyState == "complete") {
// create xmlns
if (!doc.namespaces["g_vml_"]) {
doc.namespaces.add("g_vml_", "urn:schemas-microsoft-com:vml");
}
// setup default css
var ss = doc.createStyleSheet();
ss.cssText = "canvas{display:inline-block;overflow:hidden;" +
// default size is 300x150 in Gecko and Opera
"text-align:left;width:300px;height:150px}" +
"g_vml_\\:*{behavior:url(#default#VML)}";
// find all canvas elements
var els = doc.getElementsByTagName("canvas");
for (var i = 0; i < els.length; i++) {
if (!els[i].getContext) {
this.initElement(els[i]);
}
}
}
},
fixElement_: function (el) {
// in IE before version 5.5 we would need to add HTML: to the tag name
// but we do not care about IE before version 6
var outerHTML = el.outerHTML;
var newEl = el.ownerDocument.createElement(outerHTML);
// if the tag is still open IE has created the children as siblings and
// it has also created a tag with the name "/FOO"
if (outerHTML.slice(-2) != "/>") {
var tagName = "/" + el.tagName;
var ns;
// remove content
while ((ns = el.nextSibling) && ns.tagName != tagName) {
ns.removeNode();
}
// remove the incorrect closing tag
if (ns) {
ns.removeNode();
}
}
el.parentNode.replaceChild(newEl, el);
return newEl;
},
/**
* Public initializes a canvas element so that it can be used as canvas
* element from now on. This is called automatically before the page is
* loaded but if you are creating elements using createElement you need to
* make sure this is called on the element.
* @param {HTMLElement} el The canvas element to initialize.
* @return {HTMLElement} the element that was created.
*/
initElement: function (el) {
el = this.fixElement_(el);
el.getContext = function () {
if (this.context_) {
return this.context_;
}
return this.context_ = new CanvasRenderingContext2D_(this);
};
// do not use inline function because that will leak memory
el.attachEvent('onpropertychange', onPropertyChange);
el.attachEvent('onresize', onResize);
var attrs = el.attributes;
if (attrs.width && attrs.width.specified) {
// TODO: use runtimeStyle and coordsize
// el.getContext().setWidth_(attrs.width.nodeValue);
el.style.width = attrs.width.nodeValue + "px";
} else {
el.width = el.clientWidth;
}
if (attrs.height && attrs.height.specified) {
// TODO: use runtimeStyle and coordsize
// el.getContext().setHeight_(attrs.height.nodeValue);
el.style.height = attrs.height.nodeValue + "px";
} else {
el.height = el.clientHeight;
}
//el.getContext().setCoordsize_()
return el;
}
};
function onPropertyChange(e) {
var el = e.srcElement;
switch (e.propertyName) {
case 'width':
el.style.width = el.attributes.width.nodeValue + "px";
el.getContext().clearRect();
break;
case 'height':
el.style.height = el.attributes.height.nodeValue + "px";
el.getContext().clearRect();
break;
}
}
function onResize(e) {
var el = e.srcElement;
if (el.firstChild) {
el.firstChild.style.width = el.clientWidth + 'px';
el.firstChild.style.height = el.clientHeight + 'px';
}
}
G_vmlCanvasManager_.init();
// precompute "00" to "FF"
var dec2hex = [];
for (var i = 0; i < 16; i++) {
for (var j = 0; j < 16; j++) {
dec2hex[i * 16 + j] = i.toString(16) + j.toString(16);
}
}
function createMatrixIdentity() {
return [
[1, 0, 0],
[0, 1, 0],
[0, 0, 1]
];
}
function matrixMultiply(m1, m2) {
var result = createMatrixIdentity();
for (var x = 0; x < 3; x++) {
for (var y = 0; y < 3; y++) {
var sum = 0;
for (var z = 0; z < 3; z++) {
sum += m1[x][z] * m2[z][y];
}
result[x][y] = sum;
}
}
return result;
}
function copyState(o1, o2) {
o2.fillStyle = o1.fillStyle;
o2.lineCap = o1.lineCap;
o2.lineJoin = o1.lineJoin;
o2.lineWidth = o1.lineWidth;
o2.miterLimit = o1.miterLimit;
o2.shadowBlur = o1.shadowBlur;
o2.shadowColor = o1.shadowColor;
o2.shadowOffsetX = o1.shadowOffsetX;
o2.shadowOffsetY = o1.shadowOffsetY;
o2.strokeStyle = o1.strokeStyle;
o2.arcScaleX_ = o1.arcScaleX_;
o2.arcScaleY_ = o1.arcScaleY_;
}
function processStyle(styleString) {
var str, alpha = 1;
styleString = String(styleString);
if (styleString.substring(0, 3) == "rgb") {
var start = styleString.indexOf("(", 3);
var end = styleString.indexOf(")", start + 1);
var guts = styleString.substring(start + 1, end).split(",");
str = "#";
for (var i = 0; i < 3; i++) {
str += dec2hex[Number(guts[i])];
}
if ((guts.length == 4) && (styleString.substr(3, 1) == "a")) {
alpha = guts[3];
}
} else {
str = styleString;
}
return [str, alpha];
}
function processLineCap(lineCap) {
switch (lineCap) {
case "butt":
return "flat";
case "round":
return "round";
case "square":
default:
return "square";
}
}
/**
* This class implements CanvasRenderingContext2D interface as described by
* the WHATWG.
* @param {HTMLElement} surfaceElement The element that the 2D context should
* be associated with
*/
function CanvasRenderingContext2D_(surfaceElement) {
this.m_ = createMatrixIdentity();
this.mStack_ = [];
this.aStack_ = [];
this.currentPath_ = [];
// Canvas context properties
this.strokeStyle = "#000";
this.fillStyle = "#000";
this.lineWidth = 1;
this.lineJoin = "miter";
this.lineCap = "butt";
this.miterLimit = Z * 1;
this.globalAlpha = 1;
this.canvas = surfaceElement;
var el = surfaceElement.ownerDocument.createElement('div');
el.style.width = surfaceElement.clientWidth + 'px';
el.style.height = surfaceElement.clientHeight + 'px';
el.style.overflow = 'hidden';
el.style.position = 'absolute';
surfaceElement.appendChild(el);
this.element_ = el;
this.arcScaleX_ = 1;
this.arcScaleY_ = 1;
};
var contextPrototype = CanvasRenderingContext2D_.prototype;
contextPrototype.clearRect = function() {
this.element_.innerHTML = "";
this.currentPath_ = [];
};
contextPrototype.beginPath = function() {
// TODO: Branch current matrix so that save/restore has no effect
// as per safari docs.
this.currentPath_ = [];
};
contextPrototype.moveTo = function(aX, aY) {
this.currentPath_.push({type: "moveTo", x: aX, y: aY});
this.currentX_ = aX;
this.currentY_ = aY;
};
contextPrototype.lineTo = function(aX, aY) {
this.currentPath_.push({type: "lineTo", x: aX, y: aY});
this.currentX_ = aX;
this.currentY_ = aY;
};
contextPrototype.bezierCurveTo = function(aCP1x, aCP1y,
aCP2x, aCP2y,
aX, aY) {
this.currentPath_.push({type: "bezierCurveTo",
cp1x: aCP1x,
cp1y: aCP1y,
cp2x: aCP2x,
cp2y: aCP2y,
x: aX,
y: aY});
this.currentX_ = aX;
this.currentY_ = aY;
};
contextPrototype.quadraticCurveTo = function(aCPx, aCPy, aX, aY) {
// the following is lifted almost directly from
// http://developer.mozilla.org/en/docs/Canvas_tutorial:Drawing_shapes
var cp1x = this.currentX_ + 2.0 / 3.0 * (aCPx - this.currentX_);
var cp1y = this.currentY_ + 2.0 / 3.0 * (aCPy - this.currentY_);
var cp2x = cp1x + (aX - this.currentX_) / 3.0;
var cp2y = cp1y + (aY - this.currentY_) / 3.0;
this.bezierCurveTo(cp1x, cp1y, cp2x, cp2y, aX, aY);
};
contextPrototype.arc = function(aX, aY, aRadius,
aStartAngle, aEndAngle, aClockwise) {
aRadius *= Z;
var arcType = aClockwise ? "at" : "wa";
var xStart = aX + (mc(aStartAngle) * aRadius) - Z2;
var yStart = aY + (ms(aStartAngle) * aRadius) - Z2;
var xEnd = aX + (mc(aEndAngle) * aRadius) - Z2;
var yEnd = aY + (ms(aEndAngle) * aRadius) - Z2;
// IE won't render arches drawn counter clockwise if xStart == xEnd.
if (xStart == xEnd && !aClockwise) {
xStart += 0.125; // Offset xStart by 1/80 of a pixel. Use something
// that can be represented in binary
}
this.currentPath_.push({type: arcType,
x: aX,
y: aY,
radius: aRadius,
xStart: xStart,
yStart: yStart,
xEnd: xEnd,
yEnd: yEnd});
};
contextPrototype.rect = function(aX, aY, aWidth, aHeight) {
this.moveTo(aX, aY);
this.lineTo(aX + aWidth, aY);
this.lineTo(aX + aWidth, aY + aHeight);
this.lineTo(aX, aY + aHeight);
this.closePath();
};
contextPrototype.strokeRect = function(aX, aY, aWidth, aHeight) {
// Will destroy any existing path (same as FF behaviour)
this.beginPath();
this.moveTo(aX, aY);
this.lineTo(aX + aWidth, aY);
this.lineTo(aX + aWidth, aY + aHeight);
this.lineTo(aX, aY + aHeight);
this.closePath();
this.stroke();
};
contextPrototype.fillRect = function(aX, aY, aWidth, aHeight) {
// Will destroy any existing path (same as FF behaviour)
this.beginPath();
this.moveTo(aX, aY);
this.lineTo(aX + aWidth, aY);
this.lineTo(aX + aWidth, aY + aHeight);
this.lineTo(aX, aY + aHeight);
this.closePath();
this.fill();
};
contextPrototype.createLinearGradient = function(aX0, aY0, aX1, aY1) {
var gradient = new CanvasGradient_("gradient");
return gradient;
};
contextPrototype.createRadialGradient = function(aX0, aY0,
aR0, aX1,
aY1, aR1) {
var gradient = new CanvasGradient_("gradientradial");
gradient.radius1_ = aR0;
gradient.radius2_ = aR1;
gradient.focus_.x = aX0;
gradient.focus_.y = aY0;
return gradient;
};
contextPrototype.drawImage = function (image, var_args) {
var dx, dy, dw, dh, sx, sy, sw, sh;
// to find the original width we overide the width and height
var oldRuntimeWidth = image.runtimeStyle.width;
var oldRuntimeHeight = image.runtimeStyle.height;
image.runtimeStyle.width = 'auto';
image.runtimeStyle.height = 'auto';
// get the original size
var w = image.width;
var h = image.height;
// and remove overides
image.runtimeStyle.width = oldRuntimeWidth;
image.runtimeStyle.height = oldRuntimeHeight;
if (arguments.length == 3) {
dx = arguments[1];
dy = arguments[2];
sx = sy = 0;
sw = dw = w;
sh = dh = h;
} else if (arguments.length == 5) {
dx = arguments[1];
dy = arguments[2];
dw = arguments[3];
dh = arguments[4];
sx = sy = 0;
sw = w;
sh = h;
} else if (arguments.length == 9) {
sx = arguments[1];
sy = arguments[2];
sw = arguments[3];
sh = arguments[4];
dx = arguments[5];
dy = arguments[6];
dw = arguments[7];
dh = arguments[8];
} else {
throw "Invalid number of arguments";
}
var d = this.getCoords_(dx, dy);
var w2 = sw / 2;
var h2 = sh / 2;
var vmlStr = [];
var W = 10;
var H = 10;
// For some reason that I've now forgotten, using divs didn't work
vmlStr.push(' ' coordsize="', Z * W, ',', Z * H, '"',
' coordorigin="0,0"' ,
' style="width:', W, ';height:', H, ';position:absolute;');
// If filters are necessary (rotation exists), create them
// filters are bog-slow, so only create them if abbsolutely necessary
// The following check doesn't account for skews (which don't exist
// in the canvas spec (yet) anyway.
if (this.m_[0][0] != 1 || this.m_[0][1]) {
var filter = [];
// Note the 12/21 reversal
filter.push("M11='", this.m_[0][0], "',",
"M12='", this.m_[1][0], "',",
"M21='", this.m_[0][1], "',",
"M22='", this.m_[1][1], "',",
"Dx='", mr(d.x / Z), "',",
"Dy='", mr(d.y / Z), "'");
// Bounding box calculation (need to minimize displayed area so that
// filters don't waste time on unused pixels.
var max = d;
var c2 = this.getCoords_(dx + dw, dy);
var c3 = this.getCoords_(dx, dy + dh);
var c4 = this.getCoords_(dx + dw, dy + dh);
max.x = Math.max(max.x, c2.x, c3.x, c4.x);
max.y = Math.max(max.y, c2.y, c3.y, c4.y);
vmlStr.push("padding:0 ", mr(max.x / Z), "px ", mr(max.y / Z),
"px 0;filter:progid:DXImageTransform.Microsoft.Matrix(",
filter.join(""), ", sizingmethod='clip');")
} else {
vmlStr.push("top:", mr(d.y / Z), "px;left:", mr(d.x / Z), "px;")
}
vmlStr.push(' ">' ,
' ' style="width:', Z * dw, ';',
' height:', Z * dh, ';"',
' cropleft="', sx / w, '"',
' croptop="', sy / h, '"',
' cropright="', (w - sx - sw) / w, '"',
' cropbottom="', (h - sy - sh) / h, '"',
' />',
'');
this.element_.insertAdjacentHTML("BeforeEnd",
vmlStr.join(""));
};
contextPrototype.stroke = function(aFill) {
var lineStr = [];
var lineOpen = false;
var a = processStyle(aFill ? this.fillStyle : this.strokeStyle);
var color = a[0];
var opacity = a[1] * this.globalAlpha;
var W = 10;
var H = 10;
lineStr.push(' ' fillcolor="', color, '"',
' filled="', Boolean(aFill), '"',
' style="position:absolute;width:', W, ';height:', H, ';"',
' coordorigin="0 0" coordsize="', Z * W, ' ', Z * H, '"',
' stroked="', !aFill, '"',
' strokeweight="', this.lineWidth, '"',
' strokecolor="', color, '"',
' path="');
var newSeq = false;
var min = {x: null, y: null};
var max = {x: null, y: null};
for (var i = 0; i < this.currentPath_.length; i++) {
var p = this.currentPath_[i];
if (p.type == "moveTo") {
lineStr.push(" m ");
var c = this.getCoords_(p.x, p.y);
lineStr.push(mr(c.x), ",", mr(c.y));
} else if (p.type == "lineTo") {
lineStr.push(" l ");
var c = this.getCoords_(p.x, p.y);
lineStr.push(mr(c.x), ",", mr(c.y));
} else if (p.type == "close") {
lineStr.push(" x ");
} else if (p.type == "bezierCurveTo") {
lineStr.push(" c ");
var c = this.getCoords_(p.x, p.y);
var c1 = this.getCoords_(p.cp1x, p.cp1y);
var c2 = this.getCoords_(p.cp2x, p.cp2y);
lineStr.push(mr(c1.x), ",", mr(c1.y), ",",
mr(c2.x), ",", mr(c2.y), ",",
mr(c.x), ",", mr(c.y));
} else if (p.type == "at" || p.type == "wa") {
lineStr.push(" ", p.type, " ");
var c = this.getCoords_(p.x, p.y);
var cStart = this.getCoords_(p.xStart, p.yStart);
var cEnd = this.getCoords_(p.xEnd, p.yEnd);
lineStr.push(mr(c.x - this.arcScaleX_ * p.radius), ",",
mr(c.y - this.arcScaleY_ * p.radius), " ",
mr(c.x + this.arcScaleX_ * p.radius), ",",
mr(c.y + this.arcScaleY_ * p.radius), " ",
mr(cStart.x), ",", mr(cStart.y), " ",
mr(cEnd.x), ",", mr(cEnd.y));
}
// TODO: Following is broken for curves due to
// move to proper paths.
// Figure out dimensions so we can do gradient fills
// properly
if(c) {
if (min.x == null || c.x < min.x) {
min.x = c.x;
}
if (max.x == null || c.x > max.x) {
max.x = c.x;
}
if (min.y == null || c.y < min.y) {
min.y = c.y;
}
if (max.y == null || c.y > max.y) {
max.y = c.y;
}
}
}
lineStr.push(' ">');
if (typeof this.fillStyle == "object") {
var focus = {x: "50%", y: "50%"};
var width = (max.x - min.x);
var height = (max.y - min.y);
var dimension = (width > height) ? width : height;
focus.x = mr((this.fillStyle.focus_.x / width) * 100 + 50) + "%";
focus.y = mr((this.fillStyle.focus_.y / height) * 100 + 50) + "%";
var colors = [];
// inside radius (%)
if (this.fillStyle.type_ == "gradientradial") {
var inside = (this.fillStyle.radius1_ / dimension * 100);
// percentage that outside radius exceeds inside radius
var expansion = (this.fillStyle.radius2_ / dimension * 100) - inside;
} else {
var inside = 0;
var expansion = 100;
}
var insidecolor = {offset: null, color: null};
var outsidecolor = {offset: null, color: null};
// We need to sort 'colors' by percentage, from 0 > 100 otherwise ie
// won't interpret it correctly
this.fillStyle.colors_.sort(function (cs1, cs2) {
return cs1.offset - cs2.offset;
});
for (var i = 0; i < this.fillStyle.colors_.length; i++) {
var fs = this.fillStyle.colors_[i];
colors.push( (fs.offset * expansion) + inside, "% ", fs.color, ",");
if (fs.offset > insidecolor.offset || insidecolor.offset == null) {
insidecolor.offset = fs.offset;
insidecolor.color = fs.color;
}
if (fs.offset < outsidecolor.offset || outsidecolor.offset == null) {
outsidecolor.offset = fs.offset;
outsidecolor.color = fs.color;
}
}
colors.pop();
lineStr.push(' ' color="', outsidecolor.color, '"',
' color2="', insidecolor.color, '"',
' type="', this.fillStyle.type_, '"',
' focusposition="', focus.x, ', ', focus.y, '"',
' colors="', colors.join(""), '"',
' opacity="', opacity, '" />');
} else if (aFill) {
lineStr.push('');
} else {
lineStr.push(
' ' opacity="', opacity,'"',
' joinstyle="', this.lineJoin, '"',
' miterlimit="', this.miterLimit, '"',
' endcap="', processLineCap(this.lineCap) ,'"',
' weight="', this.lineWidth, 'px"',
' color="', color,'" />'
);
}
lineStr.push("");
this.element_.insertAdjacentHTML("beforeEnd", lineStr.join(""));
this.currentPath_ = [];
};
contextPrototype.fill = function() {
this.stroke(true);
}
contextPrototype.closePath = function() {
this.currentPath_.push({type: "close"});
};
/**
* @private
*/
contextPrototype.getCoords_ = function(aX, aY) {
return {
x: Z * (aX * this.m_[0][0] + aY * this.m_[1][0] + this.m_[2][0]) - Z2,
y: Z * (aX * this.m_[0][1] + aY * this.m_[1][1] + this.m_[2][1]) - Z2
}
};
contextPrototype.save = function() {
var o = {};
copyState(this, o);
this.aStack_.push(o);
this.mStack_.push(this.m_);
this.m_ = matrixMultiply(createMatrixIdentity(), this.m_);
};
contextPrototype.restore = function() {
copyState(this.aStack_.pop(), this);
this.m_ = this.mStack_.pop();
};
contextPrototype.translate = function(aX, aY) {
var m1 = [
[1, 0, 0],
[0, 1, 0],
[aX, aY, 1]
];
this.m_ = matrixMultiply(m1, this.m_);
};
contextPrototype.rotate = function(aRot) {
var c = mc(aRot);
var s = ms(aRot);
var m1 = [
[c, s, 0],
[-s, c, 0],
[0, 0, 1]
];
this.m_ = matrixMultiply(m1, this.m_);
};
contextPrototype.scale = function(aX, aY) {
this.arcScaleX_ *= aX;
this.arcScaleY_ *= aY;
var m1 = [
[aX, 0, 0],
[0, aY, 0],
[0, 0, 1]
];
this.m_ = matrixMultiply(m1, this.m_);
};
/******** STUBS ********/
contextPrototype.clip = function() {
// TODO: Implement
};
contextPrototype.arcTo = function() {
// TODO: Implement
};
contextPrototype.createPattern = function() {
return new CanvasPattern_;
};
// Gradient / Pattern Stubs
function CanvasGradient_(aType) {
this.type_ = aType;
this.radius1_ = 0;
this.radius2_ = 0;
this.colors_ = [];
this.focus_ = {x: 0, y: 0};
}
CanvasGradient_.prototype.addColorStop = function(aOffset, aColor) {
aColor = processStyle(aColor);
this.colors_.push({offset: 1-aOffset, color: aColor});
};
function CanvasPattern_() {}
// set up externs
G_vmlCanvasManager = G_vmlCanvasManager_;
CanvasRenderingContext2D = CanvasRenderingContext2D_;
CanvasGradient = CanvasGradient_;
CanvasPattern = CanvasPattern_;
})();
} // if
/* -------------------------------------------------------------------- */
var canvas, ctx;
var canvasWidth, halfCanvasWidth;
var canvasHeight, halfCanvasHeight;
var space; // 3D Engine
var scene; // 3D Scene
/* -------------------------------------------------------------------- */
/**
* Space is a simple 3D system.
*
* Y+ = up
* Z+ = into screen
* X+ = right
*/
function Space() {
this.m = this.createMatrixIdentity();
this.mStack = [];
}
Space.prototype.createMatrixIdentity = function() {
return [
[1, 0, 0, 0],
[0, 1, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 1]
];
}
/**
* Multiplies two 4x4 matricies together.
*/
Space.prototype.matrixMultiply = function(m1, m2) {
var result = this.createMatrixIdentity();
var width = m1[0].length;
var height = m1.length;
if (width != m2.length) {
// error
}
for (var x = 0; x < width; x++) {
for (var y = 0; y < height; y++) {
var sum = 0;
for (var z = 0; z < width; z++) {
sum += m1[y][z] * m2[z][x];
}
result[y][x] = sum;
}
}
return result;
}
/**
* Transforms a coordinate using the current transformation
* matrix, then flattens it using the projection matrix.
*/
Space.prototype.flatten = function(point) {
var p = [[point.x, point.y, point.z, 1]];
var pm = this.matrixMultiply(p, this.m);
point.tx = pm[0][0];
point.ty = pm[0][1];
point.tz = pm[0][2];
// lazy projection
point.fx = halfCanvasWidth + (canvasWidth * point.tx / point.tz);
point.fy = halfCanvasHeight -(canvasWidth * point.ty / point.tz);
}
/**
* Translate (move) the current transformation matrix
*/
Space.prototype.translate = function(x, y, z) {
var m = [
[1, 0, 0, 0],
[0, 1, 0, 0],
[0, 0, 1, 0],
[x, y, z, 1]
];
this.m = this.matrixMultiply(m, this.m);
}
/**
* Rotate the current transformation matrix. Rotations are
* world-oriented, and occur in y,x,z order.
*/
Space.prototype.rotate = function(x, y, z) {
if (y) {
var cosY = Math.cos(y);
var sinY = Math.sin(y);
var rotY = [
[cosY, 0, sinY, 0],
[0, 1, 0, 0],
[-sinY, 0, cosY, 0],
[0, 0, 0, 1]
];
this.m = this.matrixMultiply(this.m, rotY);
}
if (x) {
var cosX = Math.cos(x);
var sinX = Math.sin(x);
var rotX = [
[1, 0, 0, 0],
[0, cosX, -sinX, 0],
[0, sinX, cosX,0],
[0, 0, 0, 1]
];
this.m = this.matrixMultiply(this.m, rotX);
}
if (z) {
var cosZ = Math.cos(z);
var sinZ = Math.sin(z);
var rotZ = [
[cosZ, -sinZ, 0, 0],
[sinZ, cosZ, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 1]
];
this.m = this.matrixMultiply(this.m, rotZ);
}
}
/**
* Pushes the current transformation onto the stack
*/
Space.prototype.push = function() {
this.mStack.push(this.m);
this.m = [
[this.m[0][0], this.m[0][1], this.m[0][2], this.m[0][3]],
[this.m[1][0], this.m[1][1], this.m[1][2], this.m[1][3]],
[this.m[2][0], this.m[2][1], this.m[2][2], this.m[2][3]],
[this.m[3][0], this.m[3][1], this.m[3][2], this.m[3][3]]
];
}
/**
* Pops the end off the transformation stack
*/
Space.prototype.pop = function() {
this.m = this.mStack.pop();
}
/* -------------------------------------------------------------------- */
/**
* A 3d coordinate
*/
function Point(x, y, z) {
this.x = x;
this.y = y;
this.z = z;
// Relative to camera coordinates
this.tx;
this.ty;
this.tz;
// Flattened coordinates
this.fx;
this.fy;
}
/**
* A Shape is made up of polygons
*/
function Shape() {
this.points = [];
this.polygons = [];
}
/**
* Draws the shape
*/
Shape.prototype.draw = function(drawlist) {
for (var i = 0; i< this.points.length; i++) {
space.flatten(this.points[i]);
}
for (var i = 0; i< this.polygons.length; i++) {
var poly = this.polygons[i]; // convenience
space.flatten(poly.origin);
// lazy backface culling
if (poly.normal && this.backface) {
space.flatten(poly.normal);
var originDist = Math.pow(poly.origin.tx, 2)
+ Math.pow(poly.origin.ty, 2)
+ Math.pow(poly.origin.tz, 2);
var normalDist = Math.pow(poly.normal.tx, 2)
+ Math.pow(poly.normal.ty, 2)
+ Math.pow(poly.normal.tz, 2);
if(originDist > normalDist) {
drawlist.push(poly);
}
} else {
drawlist.push(poly);
}
}
}
/**
* A polygon is a connection of points in the shape object. You
* should probably try to make them coplanar.
*/
function Polygon(points, normal, backface, type, color) {
this.points = points;
this.origin = new Point(0, 0, 0);
for(var i = 0; i < this.points.length; i++) {
this.origin.x += this.points[i].x;
this.origin.y += this.points[i].y;
this.origin.z += this.points[i].z;
}
this.origin.x /= this.points.length;
this.origin.y /= this.points.length;
this.origin.z /= this.points.length;
if (normal) {
this.normal = new Point(this.origin.x + normal.x,
this.origin.y + normal.y,
this.origin.z + normal.z);
} else {
this.normal = null;
}
this.backface = backface;
this.type = type;
this.color = color;
}
Polygon.SOLID = 0;
Polygon.WIRE = 1;
/**
* Draws the polygon. Assumes that the points have already been
* flattened.
*/
Polygon.prototype.draw = function() {
ctx.beginPath();
ctx.moveTo(this.points[0].fx, this.points[0].fy);
for(var i = 0; i < this.points.length; i++) {
ctx.lineTo(this.points[i].fx, this.points[i].fy);
}
ctx.closePath();
var color = this.color;
/*
// Do lighting here
lightvector = Math.abs(this.normal.x + this.normal.y);
if(lightvector > 1) {
lightvector = 1;
}
color[0] = (color[0] * lightvector).toString();
color[1] = (color[1] * lightvector).toString();
color[2] = (color[2] * lightvector).toString();
*/
if (color.length > 3) {
var style = ["rgba(",
color[0], ",",
color[1], ",",
color[2], ",",
color[3], ")"].join("");
} else {
var style = ["rgb(",
color[0], ",",
color[1], ",",
color[2], ")"].join("");
}
if (this.type == Polygon.SOLID) {
ctx.fillStyle = style;
ctx.fill();
} else if (this.type == Polygon.WIRE) {
ctx.strokeStyle = style;
ctx.stroke();
}
}
/* -------------------------------------------------------------------- */
/**
* Scene describes the 3D environment
*/
function Scene() {
this.shapes = {};
this.camera = new Point(0, 0, 0);
this.cameraTarget = new Point(0, 0, 0);
this.cameraRotation = 0;
this.drawlist = [];
}
/**
* Draw the world
*/
Scene.prototype.draw = function() {
space.push();
// Camera transformation
space.translate(
-this.camera.x,
-this.camera.y,
-this.camera.z
);
// Camera rotation
var xdiff = this.cameraTarget.x - this.camera.x;
var ydiff = this.cameraTarget.y - this.camera.y;
var zdiff = this.cameraTarget.z - this.camera.z;
var xzdist = Math.sqrt(Math.pow(xdiff, 2) + Math.pow(zdiff, 2));
var xrot = -Math.atan2(ydiff, xzdist); // up/down rotation
var yrot = Math.atan2(xdiff, zdiff); // left/right rotation
space.rotate(xrot, yrot, this.cameraRotation);
// Drawing
this.drawlist = [];
for(var i in this.shapes) {
this.shapes[i].draw(this.drawlist);
}
// Depth sorting (warning: this is only enough to drive this demo - feel
// free to contribute a better system).
this.drawlist.sort(function (poly1, poly2) {
return poly2.origin.tz - poly1.origin.tz;
});
for (var i = 0; i < this.drawlist.length; i++) {
this.drawlist[i].draw();
}
space.pop();
}
/* -------------------------------------------------------------------- */
var count = 0;
function loop() {
ctx.clearRect(0, 0, canvasWidth, canvasHeight);
scene.camera.x = 70*Math.sin(count);
scene.camera.y = 70;
scene.camera.z = 70*Math.cos(count);
scene.cameraRotation = count / 10;
count += 0.01;
scene.draw();
}
function load() {
// Init drawing system
canvas = document.getElementById("cv");
ctx = canvas.getContext("2d");
canvasWidth = canvas.width;
canvasHeight = canvas.height;
halfCanvasWidth = canvasWidth * 0.5;
halfCanvasHeight = canvasHeight * 0.5;
// Init 3D components
space = new Space();
scene = new Scene();
// Create a box shape and add it to the scene
scene.shapes['box'] = new Shape();
var p = scene.shapes['box'].points; // for convenience
p[0] = new Point(-10, -10, -10); // left bottom front
p[1] = new Point(10, -10, -10); // right bottom front
p[2] = new Point(10, 10, -10); // right top front
p[3] = new Point(-10, 10, -10); // left top front
p[4] = new Point(-10, -10, 10); // left bottom back
p[5] = new Point(10, -10, 10); // right bottom back
p[6] = new Point(10, 10, 10); // right top back
p[7] = new Point(-10, 10, 10); // left top back
// Back
scene.shapes['box'].polygons.push(new Polygon(
[ p[0], p[1], p[2], p[3] ],
new Point(0, 0, -1),
true /* double-sided */,
Polygon.SOLID,
[255, 0, 0]
));
// Front
scene.shapes['box'].polygons.push(new Polygon(
[ p[4], p[5], p[6], p[7] ],
new Point(0, 0, 1),
true /* double-sided */,
Polygon.SOLID,
[0, 0, 255]
));
// Top
scene.shapes['box'].polygons.push(new Polygon(
[ p[2], p[3], p[7], p[6] ],
new Point(0, 1, 0),
false /* single-sided */,
Polygon.WIRE,
[0, 255, 0]
));
// Transparent Top
scene.shapes['box'].polygons.push(new Polygon(
[ p[2], p[3], p[7], p[6] ],
new Point(0, 1, 0),
false /* single-sided */,
Polygon.SOLID,
[0, 255, 0, 0.4]
));
// Left
scene.shapes['box'].polygons.push(new Polygon(
[ p[0], p[4], p[7], p[3] ],
new Point(-1, 0, 0),
true /* double-sided */,
Polygon.SOLID,
[255, 255, 0]
));
// Right
scene.shapes['box'].polygons.push(new Polygon(
[ p[1], p[5], p[6], p[2] ],
new Point(1, 0, 0),
true /* double-sided */,
Polygon.SOLID,
[0, 255, 255]
));
// Create a floor shape and add it to the scene
scene.shapes['floor'] = new Shape();
var p = scene.shapes['floor'].points; // for convenience
p[0] = new Point(-40, -10, -40);
p[1] = new Point(-40, -10, 40);
p[2] = new Point( 40, -10, 40);
p[3] = new Point( 40, -10, -40);
// Floor
scene.shapes['floor'].polygons.push(new Polygon(
[ p[0], p[1], p[2], p[3] ],
new Point(0, 1, 0),
false /* single-sided */,
Polygon.SOLID,
[45, 45, 45]
));
setInterval('loop()', 20);
}
/* -------------------------------------------------------------------- */