演示
技术栈
本次使用了dat.gui.min.js
这个新库(就是在我文章里没有出现过的那么他们的功能有哪些呢?——可以百度搜搜)不想搜的话就听我简单絮叨两句吧。
dat.gui.min.js
就是能调节数据的功能框
使用起来也很简单例如建立一个对象
gui = {
lightY:30, //灯光y轴的位置
sphereX:0, //球的x轴的位置
sphereZ:0, //球的z轴的位置
cubeX:25, //立方体的x轴位置
cubeZ:-5 //立方体的z轴的位置
};
var datGui = new dat.GUI();
//将设置属性添加到gui当中,gui.add(对象,属性,最小值,最大值)
datGui.add(gui,"lightY",0,100);
datGui.add(gui,"sphereX",-30,30);
datGui.add(gui,"sphereZ",-30,30);
datGui.add(gui,"cubeX",0,60);
datGui.add(gui,"cubeZ",-30,30);
源码
js部分
window.addEventListener('load', function() {
var canvas = document.getElementById("animation"),
context = canvas.getContext("2d"),
width, height, resize,
gui = new dat.GUI(),
stats = new Stats(),
generatePoints,
settings = {
viewDistance: 100,
offsetFromCenter: 100,
margin: 20
},
points = [], limit = settings.offsetFromCenter, step = settings.margin, cp = {x:0,y:0,z:0};
function generateParticles() {
points = [];
limit = settings.offsetFromCenter;
step = settings.margin;
cp = {x:0,y:0,z:0};
for(var y = -limit; y < limit; y += step) {
for(var x = -limit; x < limit; x += step) {
for(var z = -limit; z < limit; z += step) {
var v = {x:x,y:y,z:z},
dx = (v.x - cp.x),
dy = (v.y - cp.y),
dz = (v.z - cp.z),
d = Math.sqrt(dx * dx + dy * dy + dz * dz),
zf = ~~(255 * (1 - (d / 150)));
if(zf < 0) zf = 0;
// generate a color based on the particle's position
v.c = {r: 255-zf, g: zf, b: zf, a: 240};
v.c.l = (v.c.r | (v.c.g << 8) | (v.c.b << 16) | (v.c.a << 24));
points.push(v);
}
}
}
}
var f1 = gui.addFolder('View'),
f2 = gui.addFolder('Particle placement');
f1.add(settings, 'viewDistance', -200, 600).step(10).name("Distance").listen().onChange(function() {
if(settings.viewDistance === 0) settings.viewDistance = -1;
});
f2.add(settings, 'offsetFromCenter', 100, 400).step(10).name("Offset from origin").onChange(generateParticles);
f2.add(settings, 'margin', 5, 40).step(5).name("Margin between").onChange(generateParticles);
f1.open();
f2.open();
gui.close();
stats.setMode(0); // FPS mode
// Place the statistics at the bottom right.
stats.domElement.style.position = 'absolute';
stats.domElement.style.right = '5px';
stats.domElement.style.bottom = '5px';
document.body.appendChild(stats.domElement);
resize = function() {
// resize the canvas
canvas.width = width = window.innerWidth;
canvas.height = height = window.innerHeight;
}; resize();
window.addEventListener('resize', resize);
window.addEventListener('mousewheel', function(event) {
if(event.wheelDeltaY < 0 || event.deltaY > 0) {
settings.viewDistance += 10;
} else {
settings.viewDistance -= 10;
}
if(settings.viewDistance == 0) settings.viewDistance = -1;
if(settings.viewDistance < -200) settings.viewDistance = -200;
if(settings.viewDistance > 600) settings.viewDistance = 600;
return event.preventDefault();
});
// generate cube
for(var y = -limit; y < limit; y += step) {
for(var x = -limit; x < limit; x += step) {
for(var z = -limit; z < limit; z += step) {
var v = {x:x,y:y,z:z},
dx = (v.x - cp.x), dy = (v.y - cp.y), dz = (v.z - cp.z),
d = Math.sqrt(dx * dx + dy * dy + dz * dz),
zf = ~~(255 * (1 - (d / 150)));
if(zf < 0) zf = 0;
// generate a color based on the particle's position
v.c = {r: 255-zf, g: zf, b: zf, a: 240};
v.c.l = (v.c.r | (v.c.g << 8) | (v.c.b << 16) | (v.c.a << 24));
points.push(v);
}
}
}
var fsin = Math.sin, fcos = Math.cos,
rotateY = 0.005, rotateX = 0.003, rotateZ = -0.001, // rotate
cosy = fcos(rotateY), siny = fsin(rotateY),
cosx = fcos(rotateX), sinx = fsin(rotateX),
cosz = fcos(rotateZ), sinz = fsin(rotateZ);
var i, c, d, dd, d32, cx, cy, cos, sin, x, y, scale, cpx, cpy, cps,
px, py, sy, sx, lx, ly, sl;
+(function render() {
stats.begin();
context.fillStyle = 'rgba(0, 0, 0, 0.6)';
context.fillRect(0, 0, width, height);
d = context.getImageData(0, 0, width, height);
dd = d.data;
d32 = new Uint32Array(dd.buffer); // create a 32-bit view for faster access
cx = width / 2;
cy = height / 2;
// further behind should be rendered first.
points.sort(function(a, b) {
return ((300 / ((a.z + settings.viewDistance) || 1)) - (300 / ((b.z + settings.viewDistance) || 1)));
})
for(i = 0; i < points.length; i += 1) {
c = points[i];
// calculate the cos and sin beforehand!
x = c.x, z = c.z, c.x = (x * cosy + z * siny), c.z = (x * -siny + z * cosy); // rotate y
z = c.z, y = c.y, c.y = (y * cosx + z * sinx), c.z = (y * -sinx + z * cosx); // rotate x
x = c.x, y = c.y, c.y = (y * cosz + x * sinz), c.x = (y * -sinz + x * cosz); // rotate z
scale = (300 / ((c.z + settings.viewDistance) || 1)), cpx = ~~(cx + c.x * scale), cpy = ~~(cy + c.y * scale), cps = scale;
sl = (2 * cps);
sy = cpy, sx = cpx, ly = ~~(sy + sl), lx = ~~(sx + sl);
if(sl > 0 && sl < 1000 && cpx >= -sl && cpy >= -sl && cpx < width && cpy < height) {
if(ly !== 0 && lx !== 0) {
for(py = sy; py < ly; py += 1) {
for(px = sx; px < lx; px += 1) {
if(px >= 0 && py >= 0 && px < width && py < height) {
d32[(py * width + px)] = c.c.l;
}
}
}
}
}
}
context.putImageData(d, 0, 0);
stats.end();
// for some reason, if I don't do this, GC doesn't come along and clean my stuff up...
// thus: memory leak, at 2.5g Chrome tells my tab to commit suicide.
// Google search: Google Chrome putImageData memory leak
// many results.
d = dd = d32 = null;
return setTimeout(function(){requestAnimFrame(render);},1);
}());
});
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