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<!DOCTYPE html>
<head>
<meta charset="utf-8"/>
<title>Търкалящ се куб</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">
void main( )
{
gl_FragColor = vec4(1,0,0,1);
}
</script>
<script>
function start( )
{
var canvas = document.getElementById("picasso");
canvas.addEventListener('webglcontextlost',function(event){event.preventDefault();},false);
canvas.addEventListener('webglcontextrestored',function(){init();},false);
init();
drawFrame();
}
function init()
{
gl = getContext("picasso",false);
glprog = getProgram("vshader","fshader");
aXYZ = gl.getAttribLocation(glprog,"aXYZ");
uProjectionMatrix = gl.getUniformLocation(glprog,"uProjectionMatrix");
uViewMatrix = gl.getUniformLocation(glprog,"uViewMatrix");
uModelMatrix = gl.getUniformLocation(glprog,"uModelMatrix");
gl.clearColor(1,1,1,1);
perspective(30,gl.canvas.width/gl.canvas.height,1,40000);
// куб 1x1x1
var data = [ 0.5,-0.5,0.5, // предна стена
0.5,0.5,0.5,
-0.5,0.5,0.5,
-0.5,-0.5,0.5,
0.5,-0.5,-0.5, // задна стена
0.5,0.5,-0.5,
-0.5,0.5,-0.5,
-0.5,-0.5,-0.5,
0.5,-0.5,0.5, // десни хоризонтални ръбове
0.5,-0.5,-0.5,
0.5,0.5,0.5,
0.5,0.5,-0.5,
-0.5,0.5,0.5, // леви хоризонтални ръбове
-0.5,0.5,-0.5,
-0.5,-0.5,0.5,
-0.5,-0.5,-0.5 ];
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);
}
var frame = 0;
function drawCube()
{
useMatrix();
gl.drawArrays(gl.LINE_LOOP,0,4);
gl.drawArrays(gl.LINE_LOOP,4,4);
gl.drawArrays(gl.LINES,8,8);
}
var angle=0;
var y=0;
var viewY=0;
var cubeY = 0;
function drawFrame()
{
frame++;
gl.clear(gl.COLOR_BUFFER_BIT);
lookAt([5,y,3], [0,y,0.5], [0,0,1]);
// главен куб
identity();
y+=0.01;
translate([0,cubeY,0]);
xRotate(angle);
translate([0, -0.5, 0.5]);
if (angle >= 89)
cubeY++;
angle = (angle + 0.9) % 90;
drawCube();
// пътека (рисува само частта около куба)
for (var v=-15; v<=15; v++)
{
identity();
scale([1.5,1,0.05]);
translate([0,v + Math.floor(y / 10) * 10,-0.5]);
drawCube();
}
requestAnimationFrame(drawFrame);
}
</script>
</head>
<body onload="start()">
<h2>Търкалящ се куб</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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