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<!DOCTYPE html>
<head>
<meta charset="utf-8"/>
<title>Ходене по ръба</title>
<script src="webgl-fmi.js"></script>
<script id="vshader" type="x-shader/x-vertex">
uniform mat4 uProjectionMatrix;
uniform mat4 uViewMatrix;
uniform mat4 uModelMatrix;
uniform mat4 uNormalMatrix; // матрица за нормалните вектори
uniform bool uUseNormalMatrix; // дали матрицата се подава отвън
uniform bool uUseAmbient;
uniform vec3 uAmbientColor;
uniform bool uUseDiffuse;
uniform vec3 uDiffuseColor;
uniform vec3 uLightDir;
attribute vec3 aXYZ;
attribute vec3 aColor;
attribute vec3 aNormal;
varying vec3 vColor;
void main ()
{
mat4 mvMatrix = uViewMatrix * uModelMatrix;
gl_Position = uProjectionMatrix * mvMatrix * vec4(aXYZ,1);
mat4 nMatrix = uUseNormalMatrix?uNormalMatrix:mvMatrix;
// околна светлина
if (uUseAmbient)
vColor = uAmbientColor*aColor;
else
vColor = aColor;
// дифузно отражение
if (uUseDiffuse)
{
vec3 light = normalize(-uLightDir);
vec3 normal = vec3(normalize(nMatrix*vec4(aNormal,0)));
vColor += aColor*uDiffuseColor*max(dot(normal,light),0.0);
}
}
</script>
<script id="fshader" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vColor;
void main( )
{
gl_FragColor = vec4(vColor,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");
glprog = getProgram("vshader","fshader");
aXYZ = gl.getAttribLocation(glprog,"aXYZ");
uProjectionMatrix = gl.getUniformLocation(glprog,"uProjectionMatrix");
uViewMatrix = gl.getUniformLocation(glprog,"uViewMatrix");
uModelMatrix = gl.getUniformLocation(glprog,"uModelMatrix");
uNormalMatrix = gl.getUniformLocation(glprog,"uNormalMatrix");
uUseNormalMatrix = gl.getUniformLocation(glprog,"uUseNormalMatrix");
aColor = gl.getAttribLocation(glprog,"aColor");
uAmbientColor = gl.getUniformLocation(glprog,"uAmbientColor");
uUseAmbient = gl.getUniformLocation(glprog,"uUseAmbient");
aNormal = gl.getAttribLocation(glprog,"aNormal");
uDiffuseColor = gl.getUniformLocation(glprog,"uDiffuseColor");
uUseDiffuse = gl.getUniformLocation(glprog,"uUseDiffuse");
uLightDir = gl.getUniformLocation(glprog,"uLightDir");
gl.enable(gl.DEPTH_TEST);
gl.clearColor(0.9,1,0.9,1);
identity();
perspective(30,gl.canvas.width/gl.canvas.height,1,40000);
gl.uniform1i(uUseNormalMatrix,false);
gl.uniform3f(uAmbientColor,0.5,0.5,0.5);
gl.uniform1i(uUseAmbient,true);
gl.uniform3f(uDiffuseColor,0.75,0.75,0.75);
gl.uniform1i(uUseDiffuse,true);
gl.uniform3f(uLightDir,0,0,-1);
// създаване на движещо се топче
ball = new Sphere([12,12,12],3);
ball.color = [0.2,0.4,0.7];
// създаване на ръбове на куб
var c = 12, e=0.5;
base = [];
// околни ръбове
base.push(new Cuboid([+c,+c,0],[e,e,c+c+e]));
base.push(new Cuboid([+c,-c,0],[e,e,c+c+e]));
base.push(new Cuboid([-c,+c,0],[e,e,c+c+e]));
base.push(new Cuboid([-c,-c,0],[e,e,c+c+e]));
// долни ръбове
base.push(new Cuboid([+c,0,-c],[e,c+c,e]));
base.push(new Cuboid([-c,0,-c],[e,c+c,e]));
base.push(new Cuboid([0,+c,-c],[c+c,e,e]));
base.push(new Cuboid([0,-c,-c],[c+c,e,e]));
// горни ръбове
base.push(new Cuboid([+c,0,+c],[e,c+c,e]));
base.push(new Cuboid([-c,0,+c],[e,c+c,e]));
base.push(new Cuboid([0,+c,+c],[c+c,e,e]));
base.push(new Cuboid([0,-c,+c],[c+c,e,e]));
}
function linearInterpolationForCuboid(p1, p2, per) {
return [
p1[0] * (1 - per) + p2[0] * per,
p1[1] * (1 - per) + p2[1] * per,
p1[2] * (1 - per) + p2[2] * per,
];
}
function linearCuboidInterpolation(cub, per) {
return linearInterpolation(per);
}
var frame = 0;
function drawFrame()
{
frame++;
gl.clear(gl.COLOR_BUFFER_BIT+gl.DEPTH_BUFFER_BIT);
lookAt([70*Math.cos(frame/300),70*Math.sin(frame/300),20], [0,0,-2], [0,0,1]);
// рисуване на куба
for (var i=0; i<12; i++)
base[i].draw();
// тук сложете код, който управлява движението
// на топчето по ръбовете, без връщане назад
ball.draw();
requestAnimationFrame(drawFrame);
}
</script>
</head>
<body onload="start()">
<h2>Ходене по ръба</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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