ThreeJS Shader的效果样例光影墙、扩散面(四)
cnblogs 2024-09-14 08:11:00 阅读 66
一、实现一个光影墙
1.根据自定义坐标点，输出一个光影墙
/**
* 添加光影墙
*/
function addLightWall() {
const geometry = new THREE.BufferGeometry();
const vertices = new Float32Array([
5, 0, 2,
3, 0, 5,
-2, 0, 5,
-4, 0, 2,
-4, 5, 2,
-2, 5, 5,
3, 5, 5,
5, 5, 2
]);
const indices = new Uint16Array([
0, 1, 7,
1, 6, 7,
1, 2, 6,
2, 5, 6,
2, 3, 5,
3, 4, 5
])
geometry.setAttribute('position', new THREE.BufferAttribute(vertices, 3));
geometry.setIndex(new THREE.BufferAttribute(indices, 1));
geometry.setAttribute('aHeight', new THREE.BufferAttribute(new Float32Array(new Array(geometry.getAttribute('position').count).fill(5.0)), 1));
const uniforms = {
uTime: { value: 0.01 },
};
setShader(geometry, vertex, frag, [0, 2.5, 0], uniforms)
}
function setShader(geometry, vertexShader, fragmentShader, position = [0, 0, 0], uniforms = {}, isLine = false) {
material = new THREE.ShaderMaterial({
vertexShader: vertexShader,
fragmentShader: fragmentShader,
side: THREE.DoubleSide,
uniforms: uniforms,
transparent: true,
// blending: THREE.AdditiveBlending, // 多个元素的颜色相互叠加，颜色可能会变亮，会叠加setClearColor设置的背景色
});
material.depthTest = true;
material.depthWrite = false;
let planeMesh = new THREE.Mesh(geometry, material);
if (isLine) {
planeMesh = new THREE.Points(geometry, material);
}
planeMesh.position.x = position[0];
planeMesh.position.y = position[1];
planeMesh.position.z = position[2];
scene.add(planeMesh);
}
自定义坐标
2.圆柱体的光影墙
/**
* 添加光影墙
*/
function addLightWall() {
const geometry = new THREE.CylinderGeometry(3, 3, 5.0, 32, 32, true);
geometry.setAttribute('aHeight', new THREE.BufferAttribute(new Float32Array(new Array(geometry.getAttribute('position').count).fill(5.0)), 1));
// 生成一个渐变色的光影墙
const vertex = `
varying vec3 vPosition;
varying vec2 vUv;
varying float vHeight;
attribute float aHeight;
void main() {
vHeight = aHeight;
vUv = uv;
vPosition = position;
gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
}
`;
const frag = `
varying vec3 vPosition;
varying vec2 vUv;
varying float vHeight;
void main() {
float d = (vHeight - distance(vPosition, vec3(vPosition.x, -2.5, vPosition.z))) / vHeight;
gl_FragColor = vec4(0.0, 1.0, 1.0, d);
}
`;
const uniforms = {
uTime: { value: 0.01 },
};
setShader(geometry, vertex, frag, [0, 2.5, 0], uniforms)
}
function setShader(geometry, vertexShader, fragmentShader, position = [0, 0, 0], uniforms = {}, isLine = false) {
material = new THREE.ShaderMaterial({
vertexShader: vertexShader,
fragmentShader: fragmentShader,
side: THREE.DoubleSide,
uniforms: uniforms,
transparent: true,
// blending: THREE.AdditiveBlending, // 多个元素的颜色相互叠加，颜色可能会变亮，会叠加setClearColor设置的背景色
});
material.depthTest = true;
material.depthWrite = false;
let planeMesh = new THREE.Mesh(geometry, material);
if (isLine) {
planeMesh = new THREE.Points(geometry, material);
}
planeMesh.position.x = position[0];
planeMesh.position.y = position[1];
planeMesh.position.z = position[2];
scene.add(planeMesh);
}
圆柱体光影墙
3.为圆柱体添加可移动的线圈
/**
* 添加光影墙
*/
function addLightWall() {
const geometry = new THREE.CylinderGeometry(3, 3, 5.0, 32, 32, true);
geometry.setAttribute('aHeight', new THREE.BufferAttribute(new Float32Array(new Array(geometry.getAttribute('position').count).fill(5.0)), 1));
// 生成一个可以向上移动的墙体线
const vertex = `
varying vec3 vPosition;
varying vec2 vUv;
varying float vHeight;
attribute float aHeight;
void main() {
vHeight = aHeight;
vUv = uv;
vPosition = position;
gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
}
`;
const frag = `
uniform float uTime;
varying vec3 vPosition;
varying vec2 vUv;
varying float vHeight;
void main() {
float dis = distance(vPosition, vec3(vPosition.x, -2.5, vPosition.z));
float highlightPos = mod(uTime * 5.0, vHeight) - 2.5;
float highlightDis = distance(vec3(vPosition.x, highlightPos, vPosition.z), vec3(vPosition.x, -2.5, vPosition.z));
float highlightOpa = (vHeight - highlightDis) / vHeight;
float opacity = (vHeight - dis) / vHeight;
if (abs(dis - highlightDis) < 0.05) {
gl_FragColor = vec4(0.04, 0.95, 0.95, highlightOpa + 0.2);
} else {
gl_FragColor = vec4(0.0, 1.0, 1.0, opacity);
}
}
`;
const uniforms = {
uTime: { value: 0.01 },
};
setShader(geometry, vertex, frag, [0, 2.5, 0], uniforms)
}
function setShader(geometry, vertexShader, fragmentShader, position = [0, 0, 0], uniforms = {}, isLine = false) {
material = new THREE.ShaderMaterial({
vertexShader: vertexShader,
fragmentShader: fragmentShader,
side: THREE.DoubleSide,
uniforms: uniforms,
transparent: true,
// blending: THREE.AdditiveBlending, // 多个元素的颜色相互叠加，颜色可能会变亮，会叠加setClearColor设置的背景色
});
material.depthTest = true;
material.depthWrite = false;
let planeMesh = new THREE.Mesh(geometry, material);
if (isLine) {
planeMesh = new THREE.Points(geometry, material);
}
planeMesh.position.x = position[0];
planeMesh.position.y = position[1];
planeMesh.position.z = position[2];
scene.add(planeMesh);
}
移动线圈光影墙
二、实现一个渐变色的波纹圆圈
1.实现一个固定的渐变色圆圈
原理：
1)UV点的范围是[0, 1]，所以各个像素点距离圆心的距离范围是0~0.5，如果乘以2刚好是透明度的范围(0~1)，这样就可以实现一个简单的渐变圆
2)假设厚度为t，那么颜色的透明度的范围是[1, 1-t]，而我们实际需要的是[1, 0]，可以用图二来表示两个线性关系，可以得到两个方程式
方程式1：y = -x + 1;
方程式2：y = -t + 1;
现在我们知道方程式二中的y的值(像素点到中心的距离distance),通过解方程式就可以得到方程式1中所对应的透明度的值为(distance - 1) /t + 1；
/**
* 添加一个扩散面
*/
function addDiffuseCircle() {
const geometry = new THREE.CircleGeometry(3, 48);
// 绘制一个渐变圈宽度可控的圆弧
const vertex = `
varying vec2 vUv;
void main() {
vUv = uv;
gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
}
`;
const frag = `
uniform float uTime;
uniform float uThickness;
varying vec2 vUv;
void main() {
// 使用UV坐标计算各个点到中心点的距离，需要减0.5，将圆心移动到(0.5, 0.5)的位置，半径为0.5，透明度范围为0~1，所以需要乘以2
float distance = length(vUv - 0.5) * 2.0;
float opacity = (distance - 1.0) / uThickness + 1.0;
gl_FragColor = vec4(0.0, 1.0, 1.0, opacity);
}
`;
const uniforms = {
uThickness: { value: 0.8, range: [0, 1] }, // 渐变色的厚度
uSpeed: { value: 0.5, range: [0, 5] },
uTime: { value: 0.01 },
};
setGui(uniforms);
setShader(geometry, vertex, frag, [0,0,0], uniforms);
}
function setShader(geometry, vertexShader, fragmentShader, position = [0, 0, 0], uniforms = {}, isLine = false) {
material = new THREE.ShaderMaterial({
vertexShader: vertexShader,
fragmentShader: fragmentShader,
side: THREE.DoubleSide,
uniforms: uniforms,
transparent: true,
// blending: THREE.AdditiveBlending, // 多个元素的颜色相互叠加，颜色可能会变亮，会叠加setClearColor设置的背景色
});
material.depthTest = true;
material.depthWrite = false;
let planeMesh = new THREE.Mesh(geometry, material);
if (isLine) {
planeMesh = new THREE.Points(geometry, material);
}
planeMesh.position.x = position[0];
planeMesh.position.y = position[1];
planeMesh.position.z = position[2];
planeMesh.rotateX(Math.PI / 2);
scene.add(planeMesh);
}
厚度可变的渐变圆
2.半径自动缩放的渐变圆
/**
* 添加一个扩散面
*/
function addDiffuseCircle() {
const geometry = new THREE.CircleGeometry(3, 48);
// 创建一个大小可控的渐变圆弧
const vertex = `
varying vec2 vUv;
void main() {
vUv = uv;
gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
}
`;
const frag = `
uniform float uTime;
uniform float uThickness;
uniform float uSpeed;
varying vec2 vUv;
void main() {
// 使用UV坐标计算各个点到中心点的距离，需要减0.5，将圆心移动到(0.5, 0.5)的位置，半径为0.5，透明度范围为0~1，所以需要乘以2
// 假设从内像外开始扩散，距离和时间关系是 最内部: 距离0，时间0；最外部：距离1，时间1，如果用1-时间的话，
// 所以此时1-时间+距离和样例1中的透明度相同
float timeDis = fract(uTime * uSpeed);
float distance = length(vUv - 0.5) * 2.0;
if (timeDis < distance) {
gl_FragColor = vec4(0.0, 0.0, 1.0, 0.0);
} else {
float opacity = (1.0 - timeDis + distance - 1.0) / uThickness + 1.0;
gl_FragColor = vec4(0.0, 1.0, 1.0, opacity);
}
}
`;
const uniforms = {
uThickness: { value: 0.8, range: [0, 1] }, // 渐变色的厚度
uSpeed: { value: 0.5, range: [0, 5] },
uTime: { value: 0.01 },
};
setShader(geometry, vertex, frag, [0,0,0], uniforms);
}
function setShader(geometry, vertexShader, fragmentShader, position = [0, 0, 0], uniforms = {}, isLine = false) {
material = new THREE.ShaderMaterial({
vertexShader: vertexShader,
fragmentShader: fragmentShader,
side: THREE.DoubleSide,
uniforms: uniforms,
transparent: true,
// blending: THREE.AdditiveBlending, // 多个元素的颜色相互叠加，颜色可能会变亮，会叠加setClearColor设置的背景色
});
material.depthTest = true;
material.depthWrite = false;
let planeMesh = new THREE.Mesh(geometry, material);
if (isLine) {
planeMesh = new THREE.Points(geometry, material);
}
planeMesh.position.x = position[0];
planeMesh.position.y = position[1];
planeMesh.position.z = position[2];
planeMesh.rotateX(Math.PI / 2);
scene.add(planeMesh);
}
自动缩放的渐变圆
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