# JavaScript和html5实现的情人节3D玫瑰花

3D玫瑰花的实现代码如下：

<!DOCTYPE html>
<html>
<title>JavaScript和html53D玫瑰花（程序员的情人节礼物）</title>
<meta charset="utf-8">
<body>
<canvas id="c" height="500" width="500"></canvas>
<script>
var b = document.body;
var c = document.getElementsByTagName('canvas')[0];
var a = c.getContext('2d');
document.body.clientWidth;
</script>
<script>
// start of submission //
with(m = Math) C = cos, S = sin, P = pow, R = random;
c.width = c.height = f = 500;
h = -250;

function p(a, b, c) {
if(c > 60) return [S(a * 7) * (13 + 5 /
(.2 + P(b * 4, 4))) - S(b) * 50, b *
f + 50,625 + C(a * 7) * (13 + 5 /
(.2 + P(b * 4, 4))) + b * 400, a * 1 - b / 2, a];
A = a * 2 - 1;
B = b * 2 - 1;
if(A * A + B * B < 1) {
if(c > 37) {
n = (j = c & 1) ? 6 : 4;
o = .5 / (a + .01) + C(b * 125) * 3 - a * 300;
w = b * h;
return [o * C(n) + w * S(n) + j * 610 - 390, o *
S(n) - w * C(n) + 550 - j * 350, 1180 + C(B + A) *
99 - j * 300, .4 - a * .1 + P(1 - B * B, -h * 6)
* .15 - a * b * .4 + C(a + b) / 5 + P(C((o * (a + 1)+
(B > 0 ? w : -w)) / 25), 30)* .1 * (1 - B * B),
o / 1e3 + .7 - o * w * 3e-6]
}
if(c > 32) {
c = c * 1.16 - .15;
o = a * 45 - 20;
w = b * b * h;
z = o * S(c) + w * C(c) + 620;
return [o * C(c) - w * S(c), 28 + C(B * .5) * 99 -
b * b * b * 60 - z / 2 - h, z, (b * b * .3 +
P((1 - (A * A)), 7) * .15 + .3) * b, b * .7]
}
o = A * (2 - b) * (80 - c * 2);
w = 99 - C(A) * 120 - C(b) * (-h - c * 4.9) +
C(P(1 - b, 7)) * 50 + c * 2;
z = o * S(c) + w * C(c) + 700;
return [o * C(c) - w * S(c), B * 99 - C(P(b, 7)) *
50 - c / 3 - z / 1.35 + 450,z, (1 - b / 1.2) *
.9 + a * .1, P((1 - b), 20) / 4 + .05]
}
}
setInterval('for(i=0;i<1e4;i++)if(s=p(R(),R(),i%46/.74)){z=s[2];
x=~~(s[0]*f/z-h);y=~~(s[1]*f/z-h);if(!m[q=y*f+x]|m[q]>z)m[q]=z,
a.fillStyle="rgb("+~(s[3]*h)+","+~(s[4]*h)+","+~(s[3]*s[3]*-80)+")",
a.fillRect(x,y,1,1)}', 0)
// end of submission //
</script>
</body>
</html>

function surface(a, b) { // I'm using a and b as parameters ranging from 0 to 1.
return {
x: a*50,
y: b*50
};
// this surface will be a square of 50x50 units of size
}

var canvas = document.body.appendChild(document.createElement("canvas")),
context = canvas.getContext("2d"),
a, b, position;
// Now I'm going to sample the surface at .1 intervals for a and b parameters:
for (a = 0; a < 1; a += .1) {
for (b = 0; b < 1; b += .1) {
position = surface(a, b);
context.fillRect(position.x, position.y, 1, 1);
}
}

function surface(a, b) {
var x = a * 100,
y = b * 100,
x0 = 50,
y0 = 50;

if ((x - x0) * (x - x0) + (y - y0) * (y - y0) < radius * radius) {
// inside the circle
return {
x: x,
y: y
};
} else {
// outside the circle
return null;
}
}

if (position = surface(a, b)) {
context.fillRect(position.x, position.y, 1, 1);
}

function surface(a, b) {
// Circle using polar coordinates
var angle = a * Math.PI * 2,
x0 = 50,
y0 = 50;
return {
x: Math.cos(angle) * radius * b + x0,
y: Math.sin(angle) * radius * b + y0
};
}

function surface(a, b) {
var x = a * 100,
y = b * 100,
x0 = 50,
y0 = 50;

if ((x - x0) * (x - x0) + (y - y0) * (y - y0) < radius * radius) {
return {
x: x,
y: y * (1 + b) / 2 // deformation
};
} else {
return null;
}
}

function surface(a, b) {
var x = a * 100,
y = b * 100,
x0 = 50,
y0 = 50;
if ((x - x0) * (x - x0) + (y - y0) * (y - y0) < radius * radius) {
return {
x: x,
y: y * (1 + b) / 2,
r: 100 + Math.floor((1 - b) * 155), // this will add a gradient
g: 50,
b: 50
};
} else {
return null;
}
}
for (a = 0; a < 1; a += .01) {
for (b = 0; b < 1; b += .001) {
if (point = surface(a, b)) {
context.fillStyle = "rgb(" + point.r + "," + point.g + "," + point.b + ")";
context.fillRect(point.x, point.y, 1, 1);
}
}
}

3D曲面和透视投影

function surface(a, b) {
var angle = a * Math.PI * 2,
length = 400;
return {

//by subtracting length/2 I have centered the tube at (0, 0, 0)
z: b * length - length / 2,
r: 0,
g: Math.floor(b * 255),
b: 0
};
}

var pX, pY, // projected on canvas x and y coordinates
perspective = 350,
halfHeight = canvas.height / 2,
halfWidth = canvas.width / 2,
cameraZ = -700;
for (a = 0; a < 1; a += .001) {
for (b = 0; b < 1; b += .01) {
if (point = surface(a, b)) {
pX = (point.x * perspective) / (point.z - cameraZ) + halfWidth;
pY = (point.y * perspective) / (point.z - cameraZ) + halfHeight;
context.fillStyle = "rgb("+point.r+","+point.g+","+point.b+")";
context.fillRect(pX, pY, 1, 1);
}
}
}

z-buffer

z-buffer在计算机图形学中是一个相当普遍的技术，在为物件进行着色时，执行“隐藏面消除”工作，使隐藏物件背后的部分就不会被显示出来。

var zBuffer = [], zBufferIndex;
for (a = 0; a < 1; a += .001) {
for (b = 0; b < 1; b += .01) {
if (point = surface(a, b)) {
pX = Math.floor((point.x * perspective) / (point.z - cameraZ) + halfWidth);
pY = Math.floor((point.y * perspective) / (point.z - cameraZ) + halfHeight);
zBufferIndex = pY * canvas.width + pX;
if ((typeof zBuffer[zBufferIndex] === "undefined") ||
(point.z < zBuffer[zBufferIndex])) {
zBuffer[zBufferIndex] = point.z;
context.fillStyle = "rgb("+point.r+","+point.g+","+point.b+")";
context.fillRect(pX, pY, 1, 1);
}
}
}
}

function surface(a, b) {
var angle = a * Math.PI * 2,
length = 400,
z = b * length - length / 2,
yAxisRotationAngle = -.4, // in radians!
rotatedX = x * Math.cos(yAxisRotationAngle) + z * Math.sin(yAxisRotationAngle),
rotatedZ = x * -Math.sin(yAxisRotationAngle) + z * Math.cos(yAxisRotationAngle);
return {
x : rotatedX,
y : y,
z : rotatedZ,
r : 0,
g : Math.floor(b * 255),
b : 0
};
}

var i;
window.setInterval(function() {
for (i = 0; i < 10000; i++) {
if (point = surface(Math.random(), Math.random())) {
pX = Math.floor((point.x * perspective) / (point.z - cameraZ) + halfWidth);
pY = Math.floor((point.y * perspective) / (point.z - cameraZ) + halfHeight);
zBufferIndex = pY * canvas.width + pX;
if ((typeof zBuffer[zBufferIndex]==="undefined")||(point.z<zBuffer[zBufferIndex])){
zBuffer[zBufferIndex] = point.z;
context.fillStyle = "rgb("+point.r+ "," + point.g + "," +point.b + ")";
context.fillRect(pX, pY, 1, 1);
}
}
}
}, 0);