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teapot-simple-crosshatch.html
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teapot-simple-crosshatch.html
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<html>
<head>
<title>Crosshatch teapot</title>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
<script type="text/javascript" src="sylvester.js"></script>
<script type="text/javascript" src="glUtils.js"></script>
<script id="per-fragment-lighting-fs" type="x-shader/x-fragment">
#ifdef GL_ES
precision highp float;
#endif
varying vec4 vTransformedNormal;
varying vec4 vPosition;
uniform float uMaterialShininess;
uniform vec3 uAmbientColor;
uniform vec3 uPointLightingLocation;
uniform vec3 uPointLightingSpecularColor;
uniform vec3 uPointLightingDiffuseColor;
uniform sampler2D uSampler;
void main(void) {
vec3 lightWeighting;
vec3 lightDirection = normalize(uPointLightingLocation - vPosition.xyz);
vec3 normal = normalize(vTransformedNormal.xyz);
float specularLightWeighting = 0.0;
vec3 eyeDirection = normalize(-vPosition.xyz);
vec3 reflectionDirection = reflect(-lightDirection, normal);
specularLightWeighting = pow(max(dot(reflectionDirection, eyeDirection), 0.0), uMaterialShininess);
float diffuseLightWeighting = max(dot(normal, lightDirection), 0.0);
lightWeighting = uAmbientColor
+ uPointLightingSpecularColor * specularLightWeighting
+ uPointLightingDiffuseColor * diffuseLightWeighting;
gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
if (length(lightWeighting) < 1.00) {
if (mod(gl_FragCoord.x + gl_FragCoord.y, 10.0) == 0.0) {
gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
}
}
if (length(lightWeighting) < 0.75) {
if (mod(gl_FragCoord.x - gl_FragCoord.y, 10.0) == 0.0) {
gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
}
}
if (length(lightWeighting) < 0.50) {
if (mod(gl_FragCoord.x + gl_FragCoord.y - 5.0, 10.0) == 0.0) {
gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
}
}
if (length(lightWeighting) < 0.3465) {
if (mod(gl_FragCoord.x - gl_FragCoord.y - 5.0, 10.0) == 0.0) {
gl_FragColor = vec4(0.0, 0.0, 0.0, 1.0);
}
}
}
</script>
<script id="per-fragment-lighting-vs" type="x-shader/x-vertex">
attribute vec3 aVertexPosition;
attribute vec3 aVertexNormal;
uniform mat4 uMVMatrix;
uniform mat4 uPMatrix;
uniform mat4 uNMatrix;
varying vec4 vTransformedNormal;
varying vec4 vPosition;
void main(void) {
vPosition = uMVMatrix * vec4(aVertexPosition, 1.0);
gl_Position = uPMatrix * vPosition;
vTransformedNormal = uNMatrix * vec4(aVertexNormal, 1.0);
}
</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, "per-fragment-lighting-fs");
var vertexShader = getShader(gl, "per-fragment-lighting-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.vertexNormalAttribute = gl.getAttribLocation(shaderProgram, "aVertexNormal");
gl.enableVertexAttribArray(shaderProgram.vertexNormalAttribute);
shaderProgram.pMatrixUniform = gl.getUniformLocation(shaderProgram, "uPMatrix");
shaderProgram.mvMatrixUniform = gl.getUniformLocation(shaderProgram, "uMVMatrix");
shaderProgram.nMatrixUniform = gl.getUniformLocation(shaderProgram, "uNMatrix");
shaderProgram.samplerUniform = gl.getUniformLocation(shaderProgram, "uSampler");
shaderProgram.materialShininessUniform = gl.getUniformLocation(shaderProgram, "uMaterialShininess");
shaderProgram.ambientColorUniform = gl.getUniformLocation(shaderProgram, "uAmbientColor");
shaderProgram.pointLightingLocationUniform = gl.getUniformLocation(shaderProgram, "uPointLightingLocation");
shaderProgram.pointLightingSpecularColorUniform = gl.getUniformLocation(shaderProgram, "uPointLightingSpecularColor");
shaderProgram.pointLightingDiffuseColorUniform = gl.getUniformLocation(shaderProgram, "uPointLightingDiffuseColor");
}
var mvMatrix;
var mvMatrixStack = [];
function mvPushMatrix(m) {
if (m) {
mvMatrixStack.push(m.dup());
mvMatrix = m.dup();
} else {
mvMatrixStack.push(mvMatrix.dup());
}
}
function mvPopMatrix() {
if (mvMatrixStack.length == 0) {
throw "Invalid popMatrix!";
}
mvMatrix = mvMatrixStack.pop();
return mvMatrix;
}
function loadIdentity() {
mvMatrix = Matrix.I(4);
}
function multMatrix(m) {
mvMatrix = mvMatrix.x(m);
}
function mvTranslate(v) {
var m = Matrix.Translation($V([v[0], v[1], v[2]])).ensure4x4();
multMatrix(m);
}
function createRotationMatrix(angle, v) {
var arad = angle * Math.PI / 180.0;
return Matrix.Rotation(arad, $V([v[0], v[1], v[2]])).ensure4x4();
}
function mvRotate(angle, v) {
multMatrix(createRotationMatrix(angle, v));
}
var pMatrix;
function perspective(fovy, aspect, znear, zfar) {
pMatrix = makePerspective(fovy, aspect, znear, zfar);
}
function setMatrixUniforms() {
gl.uniformMatrix4fv(shaderProgram.pMatrixUniform, false, new Float32Array(pMatrix.flatten()));
gl.uniformMatrix4fv(shaderProgram.mvMatrixUniform, false, new Float32Array(mvMatrix.flatten()));
var normalMatrix = mvMatrix.inverse();
normalMatrix = normalMatrix.transpose();
gl.uniformMatrix4fv(shaderProgram.nMatrixUniform, false, new Float32Array(normalMatrix.flatten()));
}
var teapotVertexPositionBuffer;
var teapotVertexNormalBuffer;
var teapotVertexIndexBuffer;
function handleLoadedTeapot(teapotData) {
teapotVertexNormalBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, teapotVertexNormalBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(teapotData.vertexNormals), gl.STATIC_DRAW);
teapotVertexNormalBuffer.itemSize = 3;
teapotVertexNormalBuffer.numItems = teapotData.vertexNormals.length / 3;
teapotVertexPositionBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, teapotVertexPositionBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(teapotData.vertexPositions), gl.STATIC_DRAW);
teapotVertexPositionBuffer.itemSize = 3;
teapotVertexPositionBuffer.numItems = teapotData.vertexPositions.length / 3;
teapotVertexIndexBuffer = gl.createBuffer();
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, teapotVertexIndexBuffer);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array(teapotData.indices), gl.STREAM_DRAW);
teapotVertexIndexBuffer.itemSize = 1;
teapotVertexIndexBuffer.numItems = teapotData.indices.length;
document.getElementById("loadingtext").textContent = "";
}
function loadTeapot() {
var request = new XMLHttpRequest();
request.open("GET", "Teapot.json");
request.onreadystatechange = function() {
if (request.readyState == 4) {
handleLoadedTeapot(JSON.parse(request.responseText));
}
}
request.send();
}
var teapotAngle = 180;
function drawScene() {
gl.viewport(0, 0, gl.viewportWidth, gl.viewportHeight);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
if (teapotVertexPositionBuffer == null || teapotVertexNormalBuffer == null || teapotVertexIndexBuffer == null) {
return;
}
perspective(45, gl.viewportWidth / gl.viewportHeight, 0.1, 100.0);
var ambientIntensity = parseFloat(document.getElementById("ambientI").value);
gl.uniform3f(shaderProgram.ambientColorUniform, ambientIntensity, ambientIntensity, ambientIntensity);
gl.uniform3f(
shaderProgram.pointLightingLocationUniform,
parseFloat(document.getElementById("lightPositionX").value),
parseFloat(document.getElementById("lightPositionY").value),
parseFloat(document.getElementById("lightPositionZ").value)
);
var specularIntensity = parseFloat(document.getElementById("specularI").value);
gl.uniform3f(shaderProgram.pointLightingSpecularColorUniform, specularIntensity, specularIntensity, specularIntensity);
var diffuseIntensity = parseFloat(document.getElementById("diffuseI").value);
gl.uniform3f(shaderProgram.pointLightingDiffuseColorUniform, diffuseIntensity, diffuseIntensity, diffuseIntensity);
loadIdentity();
mvTranslate([0, 0, -40]);
mvRotate(23.4, [1, 0, -1]);
mvRotate(teapotAngle, [0, 1, 0]);
gl.uniform1f(shaderProgram.materialShininessUniform, parseFloat(document.getElementById("shininess").value));
gl.bindBuffer(gl.ARRAY_BUFFER, teapotVertexPositionBuffer);
gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute, teapotVertexPositionBuffer.itemSize, gl.FLOAT, false, 0, 0);
gl.bindBuffer(gl.ARRAY_BUFFER, teapotVertexNormalBuffer);
gl.vertexAttribPointer(shaderProgram.vertexNormalAttribute, teapotVertexNormalBuffer.itemSize, gl.FLOAT, false, 0, 0);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, teapotVertexIndexBuffer);
setMatrixUniforms();
gl.drawElements(gl.TRIANGLES, teapotVertexIndexBuffer.numItems, gl.UNSIGNED_SHORT, 0);
}
var lastTime = 0;
function animate() {
var timeNow = new Date().getTime();
if (lastTime != 0) {
var elapsed = timeNow - lastTime;
teapotAngle += 0.05 * elapsed;
}
lastTime = timeNow;
}
function tick() {
drawScene();
animate();
}
function webGLStart() {
var canvas = document.getElementById("teapot-canvas");
initGL(canvas);
initShaders();
loadTeapot();
gl.clearColor(1.0, 1.0, 1.0, 1.0);
gl.clearDepth(1.0);
gl.enable(gl.DEPTH_TEST);
gl.depthFunc(gl.LEQUAL);
setInterval(tick, 15);
}
</script>
<style type="text/css">
#loadingtext {
position:absolute;
top:250px;
left:150px;
font-size:2em;
color: white;
}
</style>
</head>
<body onload="webGLStart();">
<canvas id="teapot-canvas" style="border: none;" width="500" height="500"></canvas>
<div id="loadingtext">Loading world...</div>
<br/>
<br/>
<h2>Material:</h2>
<table style="border: 0; padding: 10px;">
<tr>
<td><b>Shininess:</b>
<td><input type="text" id="shininess" value="32.0" />
</tr>
</table>
<h2>Point light:</h2>
<table style="border: 0; padding: 10px;">
<tr>
<td><b>Location:</b>
<td>X: <input type="text" id="lightPositionX" value="-10.0" />
<td>Y: <input type="text" id="lightPositionY" value="4.0" />
<td>Z: <input type="text" id="lightPositionZ" value="-20.0" />
</tr>
<tr>
<td><b>Specular intensity:</b>
<td>R: <input type="text" id="specularI" value="0.8" />
</tr>
<tr>
<td><b>Diffuse intensity:</b>
<td>R: <input type="text" id="diffuseI" value="0.8" />
</tr>
</table>
<h2>Ambient light:</h2>
<table style="border: 0; padding: 10px;">
<tr>
<td><b>Intensity:</b>
<td>R: <input type="text" id="ambientI" value="0.2" />
</tr>
</table>
</body>
</html>