效果：
模拟时钟效果。
代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="./绘制一个点/glMatrix.min.js"></script>
<script>
let vertexstring = `
attribute vec4 a_position;
uniform mat4 u_formMatrix;
void main(void){
gl_Position =u_formMatrix * a_position;
}
`;
let fragmentstring = `
precision mediump float;
void main(void){
gl_FragColor =vec4(1.0,1.0,0.0,1.0);
}
`;
var projMat4 = mat4.create();
var webgl;
var uniformTexture = 0;
var uniformTexture1 = 0;
var uniformAnim = 0;
var count = 0;
function webglStart() {
init();
tick();
}
function tick() {
window.setTimeout(tick, 1000);
initBuffer1();
initBuffer2();
initBuffer3();
count = count +1;
};
function init() {
initWebgl();
initShader();
}
function initWebgl() {
let webglDiv = document.getElementById('myCanvas');
webgl = webglDiv.getContext("webgl");
webgl.viewport(0, 0, webglDiv.clientWidth, webglDiv.clientHeight);
//mat4.ortho(0, webglDiv.clientWidth, webglDiv.clientHeight, 0, -1.0, 1.0, projMat4)
}
function initShader() {
let vsshader = webgl.createShader(webgl.VERTEX_SHADER);
let fsshader = webgl.createShader(webgl.FRAGMENT_SHADER);
webgl.shaderSource(vsshader, vertexstring);
webgl.shaderSource(fsshader, fragmentstring);
webgl.compileShader(vsshader);
webgl.compileShader(fsshader);
if (!webgl.getShaderParameter(vsshader, webgl.COMPILE_STATUS)) {
var err = webgl.getShaderInfoLog(vsshader);
alert(err);
return;
}
if (!webgl.getShaderParameter(fsshader, webgl.COMPILE_STATUS)) {
var err = webgl.getShaderInfoLog(fsshader);
alert(err);
return;
}
let program = webgl.createProgram();
webgl.attachShader(program, vsshader);
webgl.attachShader(program, fsshader)
webgl.linkProgram(program);
webgl.useProgram(program);
webgl.program = program
}
function initBuffer1() {
let modelView = mat4.create();
mat4.identity(modelView);
mat4.scale(modelView, [1, 1, 1]);
//一分钟 转0.5度
// (Math.PI/180) (0.5/60) *count
let angle = -Math.PI/1800 *count *5/60;
mat4.rotate(modelView,angle,[0,0,1])
let arr = [
0, 0, 0, 1,
0, 0.05, 0, 1,
0.3, 0, 0, 1,
0.3, 0, 0, 1,
0, 0.05, 0, 1,
0.3, 0.05, 0, 1
]
let pointPosition = new Float32Array(arr);
let aPsotion = webgl.getAttribLocation(webgl.program, "a_position");
let triangleBuffer = webgl.createBuffer();
webgl.bindBuffer(webgl.ARRAY_BUFFER, triangleBuffer);
webgl.bufferData(webgl.ARRAY_BUFFER, pointPosition, webgl.STATIC_DRAW);
webgl.enableVertexAttribArray(aPsotion);
webgl.vertexAttribPointer(aPsotion, 4, webgl.FLOAT, false, 4 * 4, 0);
let uniformMatrix = webgl.getUniformLocation(webgl.program, "u_formMatrix");
webgl.uniformMatrix4fv(uniformMatrix, false, modelView)
webgl.clearColor(0.0, 1.0, 0.0, 1.0);
webgl.clear(webgl.COLOR_BUFFER_BIT | webgl.DEPTH_BUFFER_BIT);
webgl.enable(webgl.DEPTH_TEST);
webgl.drawArrays(webgl.TRIANGLES, 0, 6);
}
function initBuffer2() {
let modelView1 = mat4.create();
mat4.identity(modelView1);
mat4.scale(modelView1, [1, 1, 1]);
let angle = -Math.PI/1800 *count;
mat4.rotate(modelView1,angle,[0,0,1])
let arr = [
0, 0, 0, 1,
0, 0.05, 0, 1,
0.4, 0, 0, 1,
0.4, 0, 0, 1,
0, 0.05, 0, 1,
0.4, 0.05, 0, 1
]
let pointPosition = new Float32Array(arr);
let aPsotion = webgl.getAttribLocation(webgl.program, "a_position");
let triangleBuffer = webgl.createBuffer();
webgl.bindBuffer(webgl.ARRAY_BUFFER, triangleBuffer);
webgl.bufferData(webgl.ARRAY_BUFFER, pointPosition, webgl.STATIC_DRAW);
webgl.enableVertexAttribArray(aPsotion);
webgl.vertexAttribPointer(aPsotion, 4, webgl.FLOAT, false, 4 * 4, 0);
let uniformMatrix = webgl.getUniformLocation(webgl.program, "u_formMatrix");
webgl.uniformMatrix4fv(uniformMatrix, false, modelView1)
webgl.drawArrays(webgl.TRIANGLES, 0, 6);
}
function initBuffer3() {
let modelView1 = mat4.create();
mat4.identity(modelView1);
mat4.scale(modelView1, [1, 1, 1]);
let angle = -Math.PI/30 *count;
mat4.rotate(modelView1,angle,[0,0,1])
let arr = [
0, 0, 0, 1,
0, 0.05, 0, 1,
0.8, 0, 0, 1,
0.8, 0, 0, 1,
0, 0.05, 0, 1,
0.8, 0.05, 0, 1
]
let pointPosition = new Float32Array(arr);
let aPsotion = webgl.getAttribLocation(webgl.program, "a_position");
let triangleBuffer = webgl.createBuffer();
webgl.bindBuffer(webgl.ARRAY_BUFFER, triangleBuffer);
webgl.bufferData(webgl.ARRAY_BUFFER, pointPosition, webgl.STATIC_DRAW);
webgl.enableVertexAttribArray(aPsotion);
webgl.vertexAttribPointer(aPsotion, 4, webgl.FLOAT, false, 4 * 4, 0);
let uniformMatrix = webgl.getUniformLocation(webgl.program, "u_formMatrix");
webgl.uniformMatrix4fv(uniformMatrix, false, modelView1)
webgl.drawArrays(webgl.TRIANGLES, 0, 6);
}
function draw() {
// //纹理变动
// uniformAnim = webgl.getUniformLocation(webgl.program, "anim");
// webgl.uniform1f(uniformAnim, count);
// webgl.drawArrays(webgl.TRIANGLES, 0, 6);
}
window.requestAnimFrame = (function () {
return window.requestAnimationFrame ||
window.webkitRequestAnimationFrame ||
window.mozRequestAnimationFrame ||
window.oRequestAnimationFrame ||
window.msRequestAnimationFrame ||
function (callback, element) {
};
})();
</script>
</head>
<body onload="webglStart()">
<canvas id='myCanvas' width="1024" height='768'></canvas>
</body>
</html>
