如何解决将渐变应用于BufferGeometry顶点
我有一个动画，它使用BufferGeometry创建一个粒子网格，然后使用Perlin噪波对其进行动画处理。一切都可以正常工作，但最后要做的是在网格上应用渐变。我已经尝试了所有发现的内容，但没有任何效果。我觉得使用ShaderMaterial是最好/最简单的解决方案，但是我发现的渐变代码无法正常工作，所以我想问一下实现此目的的最佳方法是什么，最好是如何做吧。
这里是指向代码笔的链接，因此您可以看到所有代码和示例。 https://codepen.io/JJGerrish/pen/oNxyJXX?editors=0010
这是我想要网格外观的示例。
我已经放弃了创建渐变着色器的尝试，因此欢迎您试用或提出更好的解决方案。
解决方法
您的问题是您正在使用uVu.y，但没有任何uv坐标，因此该值将始终为0。
您确定不想使用位置x值吗？
gl_FragColor = vec4(mix(color1,color2,smoothstep(-10.0,10.0,pos.x)),1.0);
（在下面的代码中进行平滑演示，请注意将pos变量从顶点发送到片段着色器）。
此外，为什么在着色器中而不是在JS中也不产生噪声？
//noise library
/*
* A speed-improved perlin and simplex noise algorithms for 2D.
*
* Based on example code by Stefan Gustavson (stegu@itn.liu.se).
* Optimisations by Peter Eastman (peastman@drizzle.stanford.edu).
* Better rank ordering method by Stefan Gustavson in 2012.
* Converted to Javascript by Joseph Gentle.
*
* Version 2012-03-09
*
* This code was placed in the public domain by its original author,* Stefan Gustavson. You may use it as you see fit,but
* attribution is appreciated.
*
*/
(function(global){
var module = global.noise = {};
function Grad(x,y,z) {
this.x = x; this.y = y; this.z = z;
}
Grad.prototype.dot2 = function(x,y) {
return this.x*x + this.y*y;
};
Grad.prototype.dot3 = function(x,z) {
return this.x*x + this.y*y + this.z*z;
};
var grad3 = [new Grad(1,1,0),new Grad(-1,new Grad(1,-1,1),-1),new Grad(0,-1)];
var p = [151,160,137,91,90,15,131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,190,6,148,247,120,234,75,26,197,62,94,252,219,203,117,35,11,32,57,177,33,88,237,149,56,87,174,20,125,136,171,168,68,175,74,165,71,134,139,48,27,166,77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,102,143,54,65,25,63,161,216,80,73,209,76,132,187,208,89,18,169,200,196,135,130,116,188,159,86,164,100,109,198,173,186,3,64,52,217,226,250,124,123,5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,223,183,170,213,119,248,152,2,44,154,163,70,221,153,101,155,167,43,172,9,129,22,39,253,19,98,108,110,79,113,224,232,178,185,112,104,218,246,97,228,251,34,242,193,238,210,144,12,191,179,162,241,81,51,145,235,249,14,239,107,49,192,214,31,181,199,106,157,184,84,204,176,115,121,50,45,127,4,150,254,138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180];
// To remove the need for index wrapping,double the permutation table length
var perm = new Array(512);
var gradP = new Array(512);
// This isn't a very good seeding function,but it works ok. It supports 2^16
// different seed values. Write something better if you need more seeds.
module.seed = function(seed) {
if(seed > 0 && seed < 1) {
// Scale the seed out
seed *= 65536;
}
seed = Math.floor(seed);
if(seed < 256) {
seed |= seed << 8;
}
for(var i = 0; i < 256; i++) {
var v;
if (i & 1) {
v = p[i] ^ (seed & 255);
} else {
v = p[i] ^ ((seed>>8) & 255);
}
perm[i] = perm[i + 256] = v;
gradP[i] = gradP[i + 256] = grad3[v % 12];
}
};
module.seed(0);
/*
for(var i=0; i<256; i++) {
perm[i] = perm[i + 256] = p[i];
gradP[i] = gradP[i + 256] = grad3[perm[i] % 12];
}*/
// Skewing and unskewing factors for 2,and 4 dimensions
var F2 = 0.5*(Math.sqrt(3)-1);
var G2 = (3-Math.sqrt(3))/6;
var F3 = 1/3;
var G3 = 1/6;
// 2D simplex noise
module.simplex2 = function(xin,yin) {
var n0,n1,n2; // Noise contributions from the three corners
// Skew the input space to determine which simplex cell we're in
var s = (xin+yin)*F2; // Hairy factor for 2D
var i = Math.floor(xin+s);
var j = Math.floor(yin+s);
var t = (i+j)*G2;
var x0 = xin-i+t; // The x,y distances from the cell origin,unskewed.
var y0 = yin-j+t;
// For the 2D case,the simplex shape is an equilateral triangle.
// Determine which simplex we are in.
var i1,j1; // Offsets for second (middle) corner of simplex in (i,j) coords
if(x0>y0) { // lower triangle,XY order: (0,0)->(1,1)
i1=1; j1=0;
} else { // upper triangle,YX order: (0,0)->(0,1)->(1,1)
i1=0; j1=1;
}
// A step of (1,0) in (i,j) means a step of (1-c,-c) in (x,y),and
// a step of (0,1) in (i,j) means a step of (-c,1-c) in (x,where
// c = (3-sqrt(3))/6
var x1 = x0 - i1 + G2; // Offsets for middle corner in (x,y) unskewed coords
var y1 = y0 - j1 + G2;
var x2 = x0 - 1 + 2 * G2; // Offsets for last corner in (x,y) unskewed coords
var y2 = y0 - 1 + 2 * G2;
// Work out the hashed gradient indices of the three simplex corners
i &= 255;
j &= 255;
var gi0 = gradP[i+perm[j]];
var gi1 = gradP[i+i1+perm[j+j1]];
var gi2 = gradP[i+1+perm[j+1]];
// Calculate the contribution from the three corners
var t0 = 0.5 - x0*x0-y0*y0;
if(t0<0) {
n0 = 0;
} else {
t0 *= t0;
n0 = t0 * t0 * gi0.dot2(x0,y0); // (x,y) of grad3 used for 2D gradient
}
var t1 = 0.5 - x1*x1-y1*y1;
if(t1<0) {
n1 = 0;
} else {
t1 *= t1;
n1 = t1 * t1 * gi1.dot2(x1,y1);
}
var t2 = 0.5 - x2*x2-y2*y2;
if(t2<0) {
n2 = 0;
} else {
t2 *= t2;
n2 = t2 * t2 * gi2.dot2(x2,y2);
}
// Add contributions from each corner to get the final noise value.
// The result is scaled to return values in the interval [-1,1].
return 70 * (n0 + n1 + n2);
};
// 3D simplex noise
module.simplex3 = function(xin,yin,zin) {
var n0,n2,n3; // Noise contributions from the four corners
// Skew the input space to determine which simplex cell we're in
var s = (xin+yin+zin)*F3; // Hairy factor for 2D
var i = Math.floor(xin+s);
var j = Math.floor(yin+s);
var k = Math.floor(zin+s);
var t = (i+j+k)*G3;
var x0 = xin-i+t; // The x,unskewed.
var y0 = yin-j+t;
var z0 = zin-k+t;
// For the 3D case,the simplex shape is a slightly irregular tetrahedron.
// Determine which simplex we are in.
var i1,j1,k1; // Offsets for second corner of simplex in (i,j,k) coords
var i2,j2,k2; // Offsets for third corner of simplex in (i,k) coords
if(x0 >= y0) {
if(y0 >= z0) { i1=1; j1=0; k1=0; i2=1; j2=1; k2=0; }
else if(x0 >= z0) { i1=1; j1=0; k1=0; i2=1; j2=0; k2=1; }
else { i1=0; j1=0; k1=1; i2=1; j2=0; k2=1; }
} else {
if(y0 < z0) { i1=0; j1=0; k1=1; i2=0; j2=1; k2=1; }
else if(x0 < z0) { i1=0; j1=1; k1=0; i2=0; j2=1; k2=1; }
else { i1=0; j1=1; k1=0; i2=1; j2=1; k2=0; }
}
// A step of (1,k) means a step of (1-c,-c,z),// a step of (0,k) means a step of (-c,1-c,where
// c = 1/6.
var x1 = x0 - i1 + G3; // Offsets for second corner
var y1 = y0 - j1 + G3;
var z1 = z0 - k1 + G3;
var x2 = x0 - i2 + 2 * G3; // Offsets for third corner
var y2 = y0 - j2 + 2 * G3;
var z2 = z0 - k2 + 2 * G3;
var x3 = x0 - 1 + 3 * G3; // Offsets for fourth corner
var y3 = y0 - 1 + 3 * G3;
var z3 = z0 - 1 + 3 * G3;
// Work out the hashed gradient indices of the four simplex corners
i &= 255;
j &= 255;
k &= 255;
var gi0 = gradP[i+ perm[j+ perm[k ]]];
var gi1 = gradP[i+i1+perm[j+j1+perm[k+k1]]];
var gi2 = gradP[i+i2+perm[j+j2+perm[k+k2]]];
var gi3 = gradP[i+ 1+perm[j+ 1+perm[k+ 1]]];
// Calculate the contribution from the four corners
var t0 = 0.6 - x0*x0 - y0*y0 - z0*z0;
if(t0<0) {
n0 = 0;
} else {
t0 *= t0;
n0 = t0 * t0 * gi0.dot3(x0,y0,z0); // (x,y) of grad3 used for 2D gradient
}
var t1 = 0.6 - x1*x1 - y1*y1 - z1*z1;
if(t1<0) {
n1 = 0;
} else {
t1 *= t1;
n1 = t1 * t1 * gi1.dot3(x1,y1,z1);
}
var t2 = 0.6 - x2*x2 - y2*y2 - z2*z2;
if(t2<0) {
n2 = 0;
} else {
t2 *= t2;
n2 = t2 * t2 * gi2.dot3(x2,y2,z2);
}
var t3 = 0.6 - x3*x3 - y3*y3 - z3*z3;
if(t3<0) {
n3 = 0;
} else {
t3 *= t3;
n3 = t3 * t3 * gi3.dot3(x3,y3,z3);
}
// Add contributions from each corner to get the final noise value.
// The result is scaled to return values in the interval [-1,1].
return 32 * (n0 + n1 + n2 + n3);
};
// ##### Perlin noise stuff
function fade(t) {
return t*t*t*(t*(t*6-15)+10);
}
function lerp(a,b,t) {
return (1-t)*a + t*b;
}
// 2D Perlin Noise
module.perlin2 = function(x,y) {
// Find unit grid cell containing point
var X = Math.floor(x),Y = Math.floor(y);
// Get relative xy coordinates of point within that cell
x = x - X; y = y - Y;
// Wrap the integer cells at 255 (smaller integer period can be introduced here)
X = X & 255; Y = Y & 255;
// Calculate noise contributions from each of the four corners
var n00 = gradP[X+perm[Y]].dot2(x,y);
var n01 = gradP[X+perm[Y+1]].dot2(x,y-1);
var n10 = gradP[X+1+perm[Y]].dot2(x-1,y);
var n11 = gradP[X+1+perm[Y+1]].dot2(x-1,y-1);
// Compute the fade curve value for x
var u = fade(x);
// Interpolate the four results
return lerp(
lerp(n00,n10,u),lerp(n01,n11,fade(y));
};
// 3D Perlin Noise
module.perlin3 = function(x,z) {
// Find unit grid cell containing point
var X = Math.floor(x),Y = Math.floor(y),Z = Math.floor(z);
// Get relative xyz coordinates of point within that cell
x = x - X; y = y - Y; z = z - Z;
// Wrap the integer cells at 255 (smaller integer period can be introduced here)
X = X & 255; Y = Y & 255; Z = Z & 255;
// Calculate noise contributions from each of the eight corners
var n000 = gradP[X+ perm[Y+ perm[Z ]]].dot3(x,z);
var n001 = gradP[X+ perm[Y+ perm[Z+1]]].dot3(x,z-1);
var n010 = gradP[X+ perm[Y+1+perm[Z ]]].dot3(x,y-1,z);
var n011 = gradP[X+ perm[Y+1+perm[Z+1]]].dot3(x,z-1);
var n100 = gradP[X+1+perm[Y+ perm[Z ]]].dot3(x-1,z);
var n101 = gradP[X+1+perm[Y+ perm[Z+1]]].dot3(x-1,z-1);
var n110 = gradP[X+1+perm[Y+1+perm[Z ]]].dot3(x-1,z);
var n111 = gradP[X+1+perm[Y+1+perm[Z+1]]].dot3(x-1,z-1);
// Compute the fade curve value for x,z
var u = fade(x);
var v = fade(y);
var w = fade(z);
// Interpolate
return lerp(
lerp(
lerp(n000,n100,lerp(n001,n101,w),lerp(
lerp(n010,n110,lerp(n011,n111,v);
};
})(this);
//effective animation code
var wWidth = window.innerWidth;
var wHeight = window.innerHeight;
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(75,wWidth / wHeight,0.01,1000);
camera.position.x = 0;
camera.position.y = 0; // 0
camera.position.z = 50; // 40
camera.lookAt(new THREE.Vector3(0,0));
var renderer = new THREE.WebGLRenderer({
alpha: true
});
renderer.setClearColor(0x000000,0);
document.getElementById('sec-graphical-intro').appendChild(renderer.domElement);
//Animation parameters
var rows = 50;
var cols = 100;
var separation = 1;
var perlinScale = 0.025;
var waveSpeed = 0.1;
var waveHeight = 8;
var FPS = 45;
var startTime = new Date().getTime();
var particles = 0;
var count = 0;
noise.seed(Math.random());
function createGeometry() {
var numParticles = cols * rows;
var positions = new Float32Array( numParticles * 3 );
var i = 0
var j = 0;
for ( var ix = 0; ix < cols; ix ++ ) {
for ( var iy = 0; iy < rows; iy ++ ) {
positions[i] = ix * separation - ( ( cols * separation ) / 2 ); // x
positions[i + 1] = 0; // y
positions[i + 2] = iy * separation - ( ( rows * separation ) / 2 ); // z
i += 3;
j ++;
}
}
var geometry = new THREE.BufferGeometry();
geometry.addAttribute( 'position',new THREE.BufferAttribute( positions,3 ) );
// geometry.dynamic = true;
// geometry.translate(-100,-25);
return geometry;
}
var geo = createGeometry();
var material = new THREE.ShaderMaterial( {
uniforms: {
"color1": {
type : "c",value: new THREE.Color(0x2753c9)
},"color2": {
type : "c",value: new THREE.Color(0x1dcdc0)
}
},vertexShader: `
varying vec2 vUv;
varying vec4 pos;
void main() {
vUv = uv;
gl_PointSize = 4.0;
pos = projectionMatrix * modelViewMatrix * vec4(position,1.0);
gl_Position = pos;
}
`,fragmentShader: `
uniform vec3 color1;
uniform vec3 color2;
varying vec2 vUv;
varying vec4 pos;
void main() {
if ( length( gl_PointCoord - vec2( 0.5,0.5 ) ) > 0.475 ) discard;
gl_FragColor = vec4(mix(color1,1.0);
}
`
});
particles = new THREE.Points(geo,material);
scene.add(particles);
function perlinAnimate() {
var curTime = new Date().getTime();
var positions = particles.geometry.attributes.position.array;
var i = 0
var j = 0;
for ( var ix = 0; ix < cols; ix ++ ) {
for ( var iy = 0; iy < rows; iy ++ ) {
pX = (ix * perlinScale) + ((curTime - startTime) / 1000) * waveSpeed;
pZ = (iy * perlinScale) + ((curTime - startTime) / 1000) * waveSpeed;
positions[ i + 1 ] = (noise.simplex2(pX,pZ)) * waveHeight;
i += 3;
}
}
particles.geometry.attributes.position.needsUpdate = true;
count += 0.1;
}
function render() {
renderer.render(scene,camera);
}
function animate() {
perlinAnimate();
render();
window.setTimeout(function() {
requestAnimationFrame(animate);
},1000 / FPS);
}
function refreshCanvasState() {
wWidth = window.innerWidth;
wHeight = window.innerHeight;
camera.aspect = wWidth / wHeight;
camera.updateProjectionMatrix();
renderer.setSize(wWidth,wHeight);
}
//EVENTS && INTERACTIONS
window.addEventListener('resize',refreshCanvasState,false);
animate();
refreshCanvasState();
addEvent(document,"keypress",function(e) {
e = e || window.event;
// use e.keyCode
console.log(e.keyCode);
});
function addEvent(element,eventName,callback) {
if (element.addEventListener) {
element.addEventListener(eventName,callback,false);
} else if (element.attachEvent) {
element.attachEvent("on" + eventName,callback);
} else {
element["on" + eventName] = callback;
}
}<head>
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/84/three.min.js"></script>
</head>
<body>
<section id="sec-graphical-intro"></section>
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