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<html>
<head>
<title>Learning WebGL &mdash; lesson 10</title>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
<script type="text/javascript" src="glMatrix-0.9.5.min.js"></script>
<script type="text/javascript" src="webgl-utils.js"></script>
<script id="shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec2 vTextureCoord;
uniform sampler2D uSampler;
void main(void) {
gl_FragColor = texture2D(uSampler, vec2(vTextureCoord.s, vTextureCoord.t));
}
</script>
<script id="shader-vs" type="x-shader/x-vertex">
attribute vec3 aVertexPosition;
attribute vec2 aTextureCoord;
uniform mat4 uMVMatrix;
uniform mat4 uPMatrix;
varying vec2 vTextureCoord;
void main(void) {
gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0);
vTextureCoord = aTextureCoord;
}
</script>
<script type="text/javascript">
var gl;
function initGL(canvas) {
try {
gl = canvas.getContext("experimental-webgl");
gl.viewportWidth = canvas.width;
gl.viewportHeight = canvas.height;
} catch (e) {
}
if (!gl) {
alert("Could not initialise WebGL, sorry :-(");
}
}
function getShader(gl, id) {
var shaderScript = document.getElementById(id);
if (!shaderScript) {
return null;
}
var str = "";
var k = shaderScript.firstChild;
while (k) {
if (k.nodeType == 3) {
str += k.textContent;
}
k = k.nextSibling;
}
var shader;
if (shaderScript.type == "x-shader/x-fragment") {
shader = gl.createShader(gl.FRAGMENT_SHADER);
} else if (shaderScript.type == "x-shader/x-vertex") {
shader = gl.createShader(gl.VERTEX_SHADER);
} else {
return null;
}
gl.shaderSource(shader, str);
gl.compileShader(shader);
if (!gl.getShaderParameter(shader, gl.COMPILE_STATUS)) {
alert(gl.getShaderInfoLog(shader));
return null;
}
return shader;
}
var shaderProgram;
function initShaders() {
var fragmentShader = getShader(gl, "shader-fs");
var vertexShader = getShader(gl, "shader-vs");
shaderProgram = gl.createProgram();
gl.attachShader(shaderProgram, vertexShader);
gl.attachShader(shaderProgram, fragmentShader);
gl.linkProgram(shaderProgram);
if (!gl.getProgramParameter(shaderProgram, gl.LINK_STATUS)) {
alert("Could not initialise shaders");
}
gl.useProgram(shaderProgram);
shaderProgram.vertexPositionAttribute = gl.getAttribLocation(shaderProgram, "aVertexPosition");
gl.enableVertexAttribArray(shaderProgram.vertexPositionAttribute);
shaderProgram.textureCoordAttribute = gl.getAttribLocation(shaderProgram, "aTextureCoord");
gl.enableVertexAttribArray(shaderProgram.textureCoordAttribute);
shaderProgram.pMatrixUniform = gl.getUniformLocation(shaderProgram, "uPMatrix");
shaderProgram.mvMatrixUniform = gl.getUniformLocation(shaderProgram, "uMVMatrix");
shaderProgram.samplerUniform = gl.getUniformLocation(shaderProgram, "uSampler");
}
function handleLoadedTexture(texture) {
gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL, true);
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, texture.image);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
gl.bindTexture(gl.TEXTURE_2D, null);
}
var mudTexture;
function initTexture() {
mudTexture = gl.createTexture();
mudTexture.image = new Image();
mudTexture.image.onload = function () {
handleLoadedTexture(mudTexture)
}
mudTexture.image.src = "mud.gif";
}
var mvMatrix = mat4.create();
var mvMatrixStack = [];
var pMatrix = mat4.create();
function mvPushMatrix() {
var copy = mat4.create();
mat4.set(mvMatrix, copy);
mvMatrixStack.push(copy);
}
function mvPopMatrix() {
if (mvMatrixStack.length == 0) {
throw "Invalid popMatrix!";
}
mvMatrix = mvMatrixStack.pop();
}
function setMatrixUniforms() {
gl.uniformMatrix4fv(shaderProgram.pMatrixUniform, false, pMatrix);
gl.uniformMatrix4fv(shaderProgram.mvMatrixUniform, false, mvMatrix);
}
function degToRad(degrees) {
return degrees * Math.PI / 180;
}
var currentlyPressedKeys = {};
function handleKeyDown(event) {
currentlyPressedKeys[event.keyCode] = true;
}
function handleKeyUp(event) {
currentlyPressedKeys[event.keyCode] = false;
}
var pitch = 0;
var pitchRate = 0;
var yaw = 0;
var yawRate = 0;
var xPos = 0;
var yPos = 0.4;
var zPos = 0;
var speed = 0;
function handleKeys() {
if (currentlyPressedKeys[33]) {
// Page Up
pitchRate = 0.1;
} else if (currentlyPressedKeys[34]) {
// Page Down
pitchRate = -0.1;
} else {
pitchRate = 0;
}
if (currentlyPressedKeys[37] || currentlyPressedKeys[65]) {
// Left cursor key or A
yawRate = 0.1;
} else if (currentlyPressedKeys[39] || currentlyPressedKeys[68]) {
// Right cursor key or D
yawRate = -0.1;
} else {
yawRate = 0;
}
if (currentlyPressedKeys[38] || currentlyPressedKeys[87]) {
// Up cursor key or W
speed = 0.003;
} else if (currentlyPressedKeys[40] || currentlyPressedKeys[83]) {
// Down cursor key
speed = -0.003;
} else {
speed = 0;
}
}
var worldVertexPositionBuffer = null;
var worldVertexTextureCoordBuffer = null;
function handleLoadedWorld(data) {
var lines = data.split("\n");
var vertexCount = 0;
var vertexPositions = [];
var vertexTextureCoords = [];
for (var i in lines) {
var vals = lines[i].replace(/^\s+/, "").split(/\s+/);
if (vals.length == 5 && vals[0] != "//") {
// It is a line describing a vertex; get X, Y and Z first
vertexPositions.push(parseFloat(vals[0]));
vertexPositions.push(parseFloat(vals[1]));
vertexPositions.push(parseFloat(vals[2]));
// And then the texture coords
vertexTextureCoords.push(parseFloat(vals[3]));
vertexTextureCoords.push(parseFloat(vals[4]));
vertexCount += 1;
}
}
worldVertexPositionBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, worldVertexPositionBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertexPositions), gl.STATIC_DRAW);
worldVertexPositionBuffer.itemSize = 3;
worldVertexPositionBuffer.numItems = vertexCount;
worldVertexTextureCoordBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, worldVertexTextureCoordBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertexTextureCoords), gl.STATIC_DRAW);
worldVertexTextureCoordBuffer.itemSize = 2;
worldVertexTextureCoordBuffer.numItems = vertexCount;
document.getElementById("loadingtext").textContent = "";
}
function loadWorld() {
var request = new XMLHttpRequest();
request.open("GET", "world.txt");
request.onreadystatechange = function () {
if (request.readyState == 4) {
handleLoadedWorld(request.responseText);
}
}
request.send();
}
function drawScene() {
gl.viewport(0, 0, gl.viewportWidth, gl.viewportHeight);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
if (worldVertexTextureCoordBuffer == null || worldVertexPositionBuffer == null) {
return;
}
mat4.perspective(45, gl.viewportWidth / gl.viewportHeight, 0.1, 100.0, pMatrix);
mat4.identity(mvMatrix);
mat4.rotate(mvMatrix, degToRad(-pitch), [1, 0, 0]);
mat4.rotate(mvMatrix, degToRad(-yaw), [0, 1, 0]);
mat4.translate(mvMatrix, [-xPos, -yPos, -zPos]);
gl.activeTexture(gl.TEXTURE0);
gl.bindTexture(gl.TEXTURE_2D, mudTexture);
gl.uniform1i(shaderProgram.samplerUniform, 0);
gl.bindBuffer(gl.ARRAY_BUFFER, worldVertexTextureCoordBuffer);
gl.vertexAttribPointer(shaderProgram.textureCoordAttribute, worldVertexTextureCoordBuffer.itemSize, gl.FLOAT, false, 0, 0);
gl.bindBuffer(gl.ARRAY_BUFFER, worldVertexPositionBuffer);
gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute, worldVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);
setMatrixUniforms();
gl.drawArrays(gl.TRIANGLES, 0, worldVertexPositionBuffer.numItems);
}
var lastTime = 0;
// Used to make us "jog" up and down as we move forward.
var joggingAngle = 0;
function animate() {
var timeNow = new Date().getTime();
if (lastTime != 0) {
var elapsed = timeNow - lastTime;
if (speed != 0) {
xPos -= Math.sin(degToRad(yaw)) * speed * elapsed;
zPos -= Math.cos(degToRad(yaw)) * speed * elapsed;
joggingAngle += elapsed * 0.6; // 0.6 "fiddle factor" - makes it feel more realistic :-)
yPos = Math.sin(degToRad(joggingAngle)) / 20 + 0.4
}
yaw += yawRate * elapsed;
pitch += pitchRate * elapsed;
}
lastTime = timeNow;
}
function tick() {
requestAnimFrame(tick);
handleKeys();
drawScene();
animate();
}
function webGLStart() {
var canvas = document.getElementById("lesson10-canvas");
initGL(canvas);
initShaders();
initTexture();
loadWorld();
gl.clearColor(0.0, 0.0, 0.0, 1.0);
gl.enable(gl.DEPTH_TEST);
document.onkeydown = handleKeyDown;
document.onkeyup = handleKeyUp;
tick();
}
</script>
<style type="text/css">
#loadingtext {
position:absolute;
top:250px;
left:150px;
font-size:2em;
color: white;
}
</style>
</head>
<body onload="webGLStart();">
<a href="http://learningwebgl.com/blog/?p=1067">&lt;&lt; Back to Lesson 10</a><br />
<canvas id="lesson10-canvas" style="border: none;" width="500" height="500"></canvas>
<div id="loadingtext">Loading world...</div>
<br/>
Use the cursor keys or WASD to run around, and <code>Page Up</code>/<code>Page Down</code> to
look up and down.
<br/>
<br/>
<a href="http://learningwebgl.com/blog/?p=1067">&lt;&lt; Back to Lesson 10</a>
</body>
</html>
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