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@MinaGabriel
Created November 17, 2020 16:03
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<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8"/>
<title>Translate a Triangle</title>
<body onload="main()">
<canvas id="webgl" width="400" height="400">
Please use a browser that supports "canvas"
</canvas>
</body>
<script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/webgl-utils.js"></script>
<script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/webgl-debug.js"></script>
<script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/cuon-utils.js"></script>
<script src="https://rawgit.com/huningxin/webglbook_examples/master/lib/cuon-matrix.js"></script>
<script type="text/javascript">
// MultiPoint.js (c) 2012 matsuda
// Vertex shader program
var VSHADER_SOURCE =
'attribute vec4 a_Position;\n' +
'uniform mat4 u_ModelMatrix;\n' +
'void main() {\n' +
' gl_Position = u_ModelMatrix * a_Position;\n' +
' gl_PointSize = 10.0;\n' +
'}\n';
// Fragment shader program
var FSHADER_SOURCE =
'void main() {\n' +
' gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);\n' +
'}\n';
function main() {
// Retrieve <canvas> element
var canvas = document.getElementById('webgl');
// Get the rendering context for WebGL
var gl = getWebGLContext(canvas);
if (!gl) {
console.log('Failed to get the rendering context for WebGL');
return;
}
// Initialize shaders
if (!initShaders(gl, VSHADER_SOURCE, FSHADER_SOURCE)) {
console.log('Failed to intialize shaders.');
return;
}
// Write the positions of vertices to a vertex shader
var n = initVertexBuffers(gl);
if (n < 0) {
console.log('Failed to set the positions of the vertices');
return;
}
// Specify the color for clearing <canvas>
gl.clearColor(0.0, 0.0, 0.0, 1.0);
var u_ModelMatrix = gl.getUniformLocation(gl.program, 'u_ModelMatrix');
if (!u_ModelMatrix) {
console.log('Failed to get the storage location of u_ModelMatrix');
return;
}
var modelMatrix = new Matrix4();
var x = 0.0, y = 0.0
var x_t = 0.005, y_t = 0.005, x_new= 0.0, y_new = 0.0
var tick = function () {
modelMatrix.translate(x_t, y_t, 0);
// This is important to init the canvas color
gl.clear(gl.COLOR_BUFFER_BIT);
gl.uniformMatrix4fv(u_ModelMatrix, false, modelMatrix.elements);
gl.drawArrays(gl.POINTS, 0, n);
//where x should go
x_new = x + get_random();
y_new = y + get_random();
if(x_new >= 0.9){
x_new = x_new - 0.1
}else if (x_new <= -0.9 ){
x_new = x_new + 0.1
}else if (y_new >= 0.9){
y_new = y_new - 0.9
}else if (y_new <= -0.9){
y_new = y_new + 0.1
}
x_t = x_new - x
y_t = y_new - y
x = x_new
y = y_new
requestAnimationFrame(tick, canvas)
};
tick();
}
function get_random(){
const options = [-0.1, 0, 0.1];
return options[Math.floor(Math.random() * (3))];
}
function initVertexBuffers(gl) {
var vertices = new Float32Array([
0.0, 0.0
]);
var n = 1; // The number of vertices
// Create a buffer object
var vertexBuffer = gl.createBuffer();
if (!vertexBuffer) {
console.log('Failed to create the buffer object');
return -1;
}
// Bind the buffer object to target
gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer);
// Write date into the buffer object
gl.bufferData(gl.ARRAY_BUFFER, vertices, gl.STATIC_DRAW);
var a_Position = gl.getAttribLocation(gl.program, 'a_Position');
if (a_Position < 0) {
console.log('Failed to get the storage location of a_Position');
return -1;
}
// Assign the buffer object to a_Position variable
gl.vertexAttribPointer(a_Position, 2, gl.FLOAT, false, 0, 0);
// Enable the assignment to a_Position variable
gl.enableVertexAttribArray(a_Position);
return n;
}
</script>
</head>
</html>
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