Created
February 28, 2011 17:55
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<!DOCTYPE html> | |
<html lang="en"> | |
<head> | |
<script id="fragmentShader" type="x-shader/x-fragment"> | |
#ifdef GL_ES | |
precision highp float; | |
#endif | |
void main() { | |
gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0); | |
} | |
</script> | |
<script id="vertexShader" type="x-shader/x-vertex"> | |
uniform float pointSize; | |
attribute vec2 vPosition; | |
void main() { | |
gl_PointSize = pointSize; | |
gl_Position = vec4(vPosition, 0, 1); | |
} | |
</script> | |
</head> | |
<body> | |
<canvas id="canvas-out" width="512" height="512"></canvas> | |
<script> | |
var EXAMPLE_ONE = {}; | |
(function(APP) { | |
APP.gl = document.getElementById("canvas-out").getContext("experimental-webgl"); | |
APP.setupShaders = function () { | |
var fragmentShader = APP.gl.createShader(APP.gl.FRAGMENT_SHADER); | |
APP.gl.shaderSource(fragmentShader, | |
document.getElementById("fragmentShader").firstChild.nodeValue); | |
APP.gl.compileShader(fragmentShader); | |
var vertexShader = APP.gl.createShader(APP.gl.VERTEX_SHADER); | |
APP.gl.shaderSource(vertexShader, | |
document.getElementById("vertexShader").firstChild.nodeValue); | |
APP.gl.compileShader(vertexShader); | |
APP.shaderProgram = APP.gl.createProgram(); | |
APP.gl.attachShader(APP.shaderProgram, vertexShader); | |
APP.gl.attachShader(APP.shaderProgram, fragmentShader); | |
APP.gl.linkProgram(APP.shaderProgram); | |
APP.gl.useProgram(APP.shaderProgram); | |
APP.vPosition = APP.gl.getAttribLocation(APP.shaderProgram, "vPosition"); | |
APP.gl.enableVertexAttribArray(APP.vPosition); | |
}; | |
APP.serpenski = function (n) { | |
var vertices = [[-1,-1],[0,1],[1,-1]], | |
points = [], | |
j,k; | |
points.push([0.25,0.50]); | |
for (k = 1; k < n; k++) { | |
j = Math.floor(Math.random() * 3) % 3; | |
points.push([ | |
(points[k-1][0] + vertices[j][0]) / 2.0, | |
(points[k-1][1] + vertices[j][1]) / 2.0 | |
]); | |
} | |
return points; | |
}; | |
APP.flatten = function (m) { | |
var result = [],i,j; | |
for (i=0; i < m.length; i++) { | |
for (j=0; j < m[i].length; j++) { | |
result.push(m[i][j]); | |
} | |
} | |
return result; | |
}; | |
APP.createBuffers = function () { | |
var points = APP.serpenski(APP.N); | |
APP.elemSize = points[0].length; | |
APP.vertexPositionBuffer = APP.gl.createBuffer(); | |
APP.gl.bindBuffer(APP.gl.ARRAY_BUFFER, APP.vertexPositionBuffer); | |
APP.gl.bufferData(APP.gl.ARRAY_BUFFER, | |
new Float32Array(APP.flatten(points)), APP.gl.STATIC_DRAW); | |
}; | |
APP.setUniforms = function () { | |
APP.gl.uniform1f( | |
APP.gl.getUniformLocation(APP.shaderProgram, "pointSize"), 3.0); | |
}; | |
APP.setup = function () { | |
APP.N = 5000; | |
APP.setupShaders(); | |
APP.setUniforms(); | |
APP.createBuffers(); | |
APP.gl.clearColor(1, 1, 0, 1); | |
APP.gl.clearDepth(1); | |
APP.gl.enable(APP.gl.DEPTH_TEST); | |
APP.gl.enable(0x0B10); //#define GL_POINT_SMOOTH 0x0B10 | |
APP.gl.depthFunc(APP.gl.LEQUAL); | |
}; | |
APP.display = function () { | |
APP.gl.clear(APP.gl.COLOR_BUFFER_BIT | APP.gl.DEPTH_BUFFER_BIT); | |
APP.gl.bindBuffer(APP.gl.ARRAY_BUFFER, APP.vertexPositionBuffer); | |
APP.gl.vertexAttribPointer( | |
APP.vPosition, APP.elemSize, APP.gl.FLOAT, false, 0, 0); | |
APP.gl.drawArrays(APP.gl.POINTS, 0, APP.N); | |
}; | |
}(EXAMPLE_ONE)); | |
EXAMPLE_ONE.setup(); | |
(function loop() { | |
window.setTimeout(function() { | |
EXAMPLE_ONE.display(); | |
loop(); | |
}, 10); | |
}()); | |
</script> | |
</body> | |
</html> |
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