基本信息
源码名称：H5支持canvas(旋转效果)
源码大小：0.07M
文件格式：.zip
开发语言：js
更新时间：2019-03-19
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源码介绍
<!--
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.
-->
<html>
<head>
<title>ExplorerCanvas Example 1</title>
<!--[if IE]><script type="text/javascript" src="../excanvas.js"></script><![endif]-->
<script type="text/javascript">
/* -------------------------------------------------------------------- */
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);
}
/* -------------------------------------------------------------------- */
</script>
<style>
body {
background-color:black;
margin:50px;
text-align:center;
}
</style>
</head>
<body onload="load();">
<canvas id="cv" width="400" height="300"></canvas>
</body>
</html>