javascript - .points 不透明度/大小在三个.js 中
问题描述
我回来回答关于.points 的第二个问题。这次想知道如何将不透明度从 0 更改为 1,然后在距发射器的特定像素距离内更改。
var particleCount = 14,
particles = new THREE.Geometry(),
pMaterial = new THREE.PointsMaterial({
map: new THREE.TextureLoader().load("x.png"),
blending: THREE.multiplyBlending,
flatShading: true,
size: 40,
transparent: true,
depthTest: true,
sizeAttenuation: true,
opacity: 1
});
var particleSystem;
我的主要困惑是,即使我给了它透明度,我也无法更改我为发射器所做的更新组合中的值。
function update() {
//particleSystem.rotation.y += 0.01;
pCount = particleCount;
while (pCount--) {
particle = particles.vertices[pCount];
(这是一堆验证点所在的位置)
particleSystem.geometry.verticesNeedUpdate = true;
particleSystem.rotation.y += (Math.random()*0.001)
}
渲染循环:
renderer.setAnimationLoop(() => {
update();
composer.render(scene, camera);
});
我想让它淡出并且不在场景中出现 20 个左右像素然后淡入。但我不完全确定如何更改不透明度,因为particle.opacity += 0.1 不起作用。
编辑:我也不确定大小,因为我想用它做类似的事情,但从 20 到 40,我可能会根据它的 Y 坐标来确定它。反正; 我也不确定如何逐渐改变它。
抱歉,如果这是一个明显的答案,重复的问题以及我得到的任何帮助。我所看到的任何替代方法都在我不理解的替代结构中,或者在我不知道如何放入我想要的东西的数组中。
(提前致谢)
解决方案
问题是不透明度和大小是THREE.PointsMaterial
. 如果品脱应该有不同的大小,那么在一个中包含不同顶点的列表是不够的THREE.Points
。必须有一个THREE.Points
带有不同HREE.PointsMaterial
s的不同列表。
创建一个THREE.Points
包含不同材料的列表:
var texture = new THREE.TextureLoader().load( "..." );
var particleSystemCount = 14;
var particleSystems = [];
for (var i = 0; i < particleSystemCount; ++ i) {
var geometry = new THREE.Geometry();
var pMaterial = new THREE.PointsMaterial({
size: 20,
map: texture,
blending: THREE.AdditiveBlending,
transparent: true,
depthTest: false,
sizeAttenuation: true,
opacity: 0
});
// ...
var points = new THREE.Points(geometry, pMaterial);
scene.add(points);
particleSystems.push(points);
}
所以在update
不透明度和大小可以单独改变:
function update() {
for (var i = 0; i < particleSystems.length; ++ i) {
var points = particleSystems[i];
var material = points.material;
var particle = points.geometry.vertices[0];
// ....
if ( material.size < 40 )
material.size += 0.5;
if ( material.opacity < 1 )
material.opacity += 0.01;
// ....
}
}
var canvas_w = window.innerWidth, canvas_h = window.innerHeight;
var scene = new THREE.Scene();
var camera = new THREE.PerspectiveCamera(60, canvas_w/canvas_h, 1, 1000);
camera.position.set(0, 0, 400);
var renderer = new THREE.WebGLRenderer();
renderer.setSize(canvas_w, window.innerHeight);
document.body.appendChild(renderer.domElement);
window.onresize = function() {
canvas_w = window.innerWidth, canvas_h = window.innerHeight;
renderer.setSize(canvas_w, canvas_h);
camera.aspect = canvas_w/canvas_h;
camera.updateProjectionMatrix();
}
var texture = new THREE.TextureLoader().load("https://threejs.org/examples/textures/sprites/circle.png");
var particleSystemCount = 14;
var particleSystems = [];
for (var i = 0; i < particleSystemCount; ++ i) {
var geometry = new THREE.Geometry();
var pMaterial = new THREE.PointsMaterial({
size: 20,
map: texture,
blending: THREE.AdditiveBlending,
transparent: true,
depthTest: false,
sizeAttenuation: true,
opacity: 0
});
var px = (Math.random() - 0.5) * 100;
var py = (Math.random() - 0.5) * 100 + 200;
var pz = (Math.random() - 0.5) * 100;
var particle = new THREE.Vector3(px, py, pz);
particle.velocity = new THREE.Vector3(0, 0, 0);
geometry.vertices.push(particle);
var points = new THREE.Points(geometry, pMaterial);
scene.add(points);
particleSystems.push(points);
}
function update() {
for (var i = 0; i < particleSystems.length; ++ i) {
var points = particleSystems[i];
var material = points.material;
var particle = points.geometry.vertices[0];
if (particle.y < -200) {
particle.x = (Math.random() - 0.5) * 100;
particle.y = (Math.random() - 0.5) * 100 + 200;
particle.z = (Math.random() - 0.5) * 100;
particle.velocity.y = 0;
material.size = 20;
material.opacity = 0;
}
particle.velocity.y -= Math.random() * .1;
particle.add(particle.velocity);
if ( material.size < 40 )
material.size += 0.25;
if ( material.opacity < 1 )
material.opacity += 0.01;
points.geometry.verticesNeedUpdate = true;
points.rotation.y += (Math.random()*0.001)
}
}
renderer.setAnimationLoop(() => {
update();
renderer.render(scene, camera);
});
body { overflow: hidden; margin: 0; }
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/99/three.min.js"></script>
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