<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport"
content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Title</title>
<style>
body {
margin: 0;
}
#canvas {
margin: 0;
display: block;
}
</style>
</head>
<body onload="main()">
<canvas id="canvas" height="800" width="1200"></canvas>
</body>
<script src="/lib/webgl-utils.js"></script>
<script src="/lib/webgl-debug.js"></script>
<script src="/lib/cuon-utils.js"></script>
<script src="/lib/cuon-matrix.js"></script>
<script>
//顶点着色器
var vertexShaderSource = "" +
"attribute vec4 a_Position;\n" +
"attribute vec2 a_TextCoord;\n" +
"uniform mat4 u_MvpMatrix;\n" +
"varying vec2 v_TexCoord;\n" +
"void main(){\n" +
" gl_Position = u_MvpMatrix * a_Position;\n" +
" v_TexCoord = a_TextCoord;\n" +
"}\n";
//片元着色器
var fragmentShaderSource = "" +
"#ifdef GL_ES\n" +
"precision mediump float;\n" +
"#endif\n" +
"uniform sampler2D u_Sampler;\n" +
"varying vec2 v_TexCoord;\n" +
"void main(){\n" +
" gl_FragColor = texture2D(u_Sampler,v_TexCoord);\n" +
"}\n";
function main() {
var canvas = document.getElementById("canvas");
setCss();
window.onresize = function () {
setCss();
};
function setCss() {
canvas.height = window.innerHeight;
canvas.width = window.innerWidth;
canvas.style.width = canvas.width+"px";
canvas.style.height = canvas.height+"px";
}
var gl = getWebGLContext(canvas);
//初始化着色器
initShaders(gl, vertexShaderSource, fragmentShaderSource);
gl.clearColor(0.0, 0.0, 0.0, 1.0);
gl.enable(gl.DEPTH_TEST);
var u_MvpMatrix = gl.getUniformLocation(gl.program, "u_MvpMatrix");
if (!u_MvpMatrix) {
console.log("无法获取变量相关的存储位置");
return;
}
//获取需要绘制图形的次数
var n = initVertexBuffers(gl);
if (n < 0) {
console.log("创建缓冲区失败");
return;
}
//定义一个保存现在角度的数组[x,y,z]
var currentAngle = [0.0,0.0,10.0];
//添加交互的方法
initEventHandlers(canvas,currentAngle);
//将纹理存入着色器
if(!initTextures(gl)){
console.log("无法获取到纹理");
return;
}
//设置一个定时绘制的函数
var tick = function() { // Start drawing
draw(gl, n, u_MvpMatrix,currentAngle);
requestAnimationFrame(tick);
};
tick();
}
function initEventHandlers(canvas, currentAngle) {
//添加拖拽事件
canvas.onmousedown = function (e) {
var downX = e.clientX;
var downY = e.clientY;
var factorX = 0.3;
var factorY = 0.2;
var beforeAngle = [];
beforeAngle[0] = currentAngle[0];
beforeAngle[1] = currentAngle[1];
beforeAngle[2] = currentAngle[2];
document.onmousemove = function (e) {
var moveX = e.clientX;
var moveY = e.clientY;
var x = factorX * (moveX - downX);
var y = factorY * (moveY - downY);
currentAngle[0] = Math.max(Math.min(beforeAngle[0] + y, 90.0), -90.0);
currentAngle[1] = beforeAngle[1] + x;
};
document.onmouseup = function () {
document.onmousemove = null;
document.onmouseup = null;
}
};
function wheel(e) {
console.log(e);
if (e.wheelDelta) {
//除了firfox浏览器，别的浏览器的处理
changeZ(-e.wheelDelta / 120, e);
} else if (e.detail) {
//firefox浏览器的测试
if (e.detail === -3) {
changeZ(-1, e);
} else if (e.detail === 3) {
changeZ(1, e);
} else {
console.log("鼠标滚轮事件改了？", e);
}
}
}
function changeZ(index) {
console.log(currentAngle[2]);
currentAngle[2] = Math.max(Math.min(currentAngle[2] += index/5,20.0),1.0);
}
//添加鼠标滚轮事件
canvas.addEventListener("mousewheel",wheel);
canvas.addEventListener("DOMMouseScroll",wheel);//兼容火狐
}
function initVertexBuffers(gl) {
// Create a cube
// v6----- v5
// /| /|
// v1------v0|
// | | | |
// | |v7---|-|v4
// |/ |/
// v2------v3
var vertices = new Float32Array([ // Vertex coordinates
1.0, 1.0, 1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0, 1.0, // v0-v1-v2-v3 front
1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0, // v0-v3-v4-v5 right
1.0, 1.0, 1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, 1.0, // v0-v5-v6-v1 up
-1.0, 1.0, 1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, 1.0, // v1-v6-v7-v2 left
-1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, 1.0, -1.0, -1.0, 1.0, // v7-v4-v3-v2 down
1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, -1.0 // v4-v7-v6-v5 back
]);
var texCoords = new Float32Array([ // Texture coordinates
1.0, 1.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, // v0-v1-v2-v3 front
0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 1.0, 1.0, // v0-v3-v4-v5 right
1.0, 0.0, 1.0, 1.0, 0.0, 1.0, 0.0, 0.0, // v0-v5-v6-v1 up
1.0, 1.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, // v1-v6-v7-v2 left
0.0, 0.0, 1.0, 0.0, 1.0, 1.0, 0.0, 1.0, // v7-v4-v3-v2 down
0.0, 0.0, 1.0, 0.0, 1.0, 1.0, 0.0, 1.0 // v4-v7-v6-v5 back
]);
// Indices of the vertices
var indices = new Uint8Array([
0, 1, 2, 0, 2, 3, // front
4, 5, 6, 4, 6, 7, // right
8, 9, 10, 8, 10, 11, // up
12, 13, 14, 12, 14, 15, // left
16, 17, 18, 16, 18, 19, // down
20, 21, 22, 20, 22, 23 // back
]);
//上面的立方的顶点坐标，纹理坐标和索引都是偷的教程上面的
//将顶点和纹理坐标都存储到缓冲区
if (!initArrayBuffer(gl, vertices, 3, gl.FLOAT, "a_Position")) {
return -1;
}
if (!initArrayBuffer(gl, texCoords, 2, gl.FLOAT, "a_TextCoord")) {
return -1;
}
//处理下标
var indexBuffer = gl.createBuffer();
if (!indexBuffer) {
console.log("无法创建缓冲区");
return -1;
}
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indices, gl.STATIC_DRAW);
return indices.length;
}
function initArrayBuffer(gl, data, num, type, attribute) {
var buffer = gl.createBuffer();
if (!buffer) {
console.log("无法创建缓冲区对象");
return;
}
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, data, gl.STATIC_DRAW);
var a_attribute = gl.getAttribLocation(gl.program, attribute);
if (a_attribute < 0) {
console.log("无法获取" + attribute + "变量的存储位置");
return false;
}
gl.vertexAttribPointer(a_attribute, num, type, false, 0, 0);
gl.enableVertexAttribArray(a_attribute);
return true;
}
function initTextures(gl) {
var texture = gl.createTexture();
if(!texture){
console.log("无法创建纹理对象");
return false;
}
var u_Sampler = gl.getUniformLocation(gl.program, "u_Sampler");
if(!u_Sampler){
console.log("无法获取到变量的存储位置");
return false;
}
var image = new Image();
image.onload = function () {
loadTexture(gl,texture,u_Sampler,image);
};
image.src = "/lib/resources/sky_cloud.jpg";
return true;
}
/* 设置纹理相关信息供WebGL使用，并进行绘制*/
function loadTexture(gl,texture,u_Sampler,image) {
//对纹理图像进行y轴反转
gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL,1);
//开启0号纹理单元
gl.activeTexture(gl.TEXTURE0);
//向target绑定纹理对象
gl.bindTexture(gl.TEXTURE_2D,texture);
//配置纹理参数
gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_MIN_FILTER,gl.LINEAR);
//配置纹理图像
gl.texImage2D(gl.TEXTURE_2D,0,gl.RGB,gl.RGB,gl.UNSIGNED_BYTE,image);
//将0号纹理传递给着色器
gl.uniform1i(u_Sampler,0);
}
function draw(gl, n, u_MvpMatrix,currentAngle) {
//设置视点位置
var viewProjectionMatrix = new Matrix4();
viewProjectionMatrix.setPerspective(30.0, canvas.width / canvas.height, 1.0, 100.0);
//console.log(30.0, canvas.width / canvas.height, 1.0, 100.0);
viewProjectionMatrix.lookAt(0.0, 0.0, currentAngle[2], 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
var mvpMatrix = new Matrix4();
mvpMatrix.set(viewProjectionMatrix);
mvpMatrix.rotate(currentAngle[0], 1.0, 0.0, 0.0);
mvpMatrix.rotate(currentAngle[1], 0.0, 1.0, 0.0);
gl.uniformMatrix4fv(u_MvpMatrix, false, mvpMatrix.elements);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
gl.drawElements(gl.TRIANGLES, n, gl.UNSIGNED_BYTE, 0);
}
</script>
</html> 一个人的力量不如两个人的，两个人的力量不如一群人的。欢迎加入大家庭一起共同学习，共同进步。