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<!DOCTYPE html>
<head>
<meta charset="utf-8"/>
<title>Плочки по сфера</title>
<script src="webgl-fmi.js"></script>
<script id="vshader" type="x-shader/x-vertex">
uniform mat4 uProjectionMatrix;
uniform mat4 uViewMatrix;
uniform mat4 uModelMatrix;
attribute vec3 aXYZ;
void main ()
{
gl_Position = uProjectionMatrix * uViewMatrix * uModelMatrix * vec4(aXYZ,1);
}
</script>
<script id="fshader" type="x-shader/x-fragment">
precision mediump float;
uniform vec3 uColor;
void main( )
{
gl_FragColor = vec4(uColor,1);
}
</script>
<script>
// рисуване на случайна плочка на случайно място по
// сфера, без да се ползва мащабиране със scale()
function plate(radius)
{
identity();
xRotate(random(0, 360));
yRotate(random(0, 360));
zRotate(random(0, 360));
translate([0, 0, radius]);
useMatrix();
gl.drawArrays(gl.LINE_LOOP,0,4);
gl.drawArrays(gl.LINE_LOOP,4,4);
gl.drawArrays(gl.LINES,8,8);
}
function start( )
{
gl = getContext("picasso");
glprog = getProgram("vshader","fshader");
aXYZ = gl.getAttribLocation(glprog,"aXYZ");
uColor = gl.getUniformLocation(glprog,"uColor");
uProjectionMatrix = gl.getUniformLocation(glprog,"uProjectionMatrix");
uViewMatrix = gl.getUniformLocation(glprog,"uViewMatrix");
uModelMatrix = gl.getUniformLocation(glprog,"uModelMatrix");
gl.clearColor(1,1,1,1);
gl.clear(gl.COLOR_BUFFER_BIT);
var proj = perspMatrix(30,gl.canvas.width/gl.canvas.height,1,40000);
gl.uniformMatrix4fv(uProjectionMatrix,false,proj);
// гледане към сферата
// [25, 0, 0]
var view = viewMatrix([20, 1, 1], [0,0,0], [0,0,1]);
gl.uniformMatrix4fv(uViewMatrix,false,view);
// паралелепипед 1x1x0.5
var data = [ 0.5,-0.5,0.125, // предна стена
0.5,0.5,0.125,
-0.5,0.5,0.125,
-0.5,-0.5,0.125,
0.5,-0.5,-0.125, // задна стена
0.5,0.5,-0.125,
-0.5,0.5,-0.125,
-0.5,-0.5,-0.125,
0.5,-0.5,0.125, // десни хоризонтални ръбове
0.5,-0.5,-0.125,
0.5,0.5,0.125,
0.5,0.5,-0.125,
-0.5,0.5,0.125, // леви хоризонтални ръбове
-0.5,0.5,-0.125,
-0.5,-0.5,0.125,
-0.5,-0.5,-0.125
];
var buf = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER,buf);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(data), gl.STATIC_DRAW);
gl.enableVertexAttribArray(aXYZ);
gl.vertexAttribPointer(aXYZ,3,gl.FLOAT,false,0,0);
// оранжеви плочки
gl.uniform3f(uColor,1,0.5,0);
// 200 случайни плочки
identity();
for( var i=0; i<200; i++ ) plate(4);
identity();
useMatrix();
data = [ 0, 0, 0, 1, 0, 0, // red
0, 0, 0, 0, 1, 0, // green
0, 0, 0, 0, 0, 1,];// blue
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(data), gl.STATIC_DRAW);
gl.uniform3f(uColor, 1, 0, 0);
gl.drawArrays(gl.LINES, 0, 2);
gl.uniform3f(uColor, 0, 1, 0);
gl.drawArrays(gl.LINES, 2, 2);
gl.uniform3f(uColor, 0, 0, 1);
gl.drawArrays(gl.LINES, 4, 2);
}
</script>
</head>
<body onload="start()">
<h2>Плочки по сфера</h2>
<noscript>
Искаме JavaScript, но няма!
</noscript>
<canvas id="picasso" width="600" height="400" style="border: solid;">
Искаме canvas, но няма!
</canvas>
</body>
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