Three.js自定义shader实现离相机越近越透明效果

const customShader = new THREE.ShaderMaterial({
    uniforms: {},
    defines: { nearDis: 0.3 },
    transparent: true,
    side: THREE.DoubleSide,
    vertexShader: `
    varying vec2 vUv;
    varying float opacity;

    void main() {
        vUv = uv;
        float dis = distance(position,cameraPosition);
        opacity = 1.0;
        if(dis < nearDis){
            opacity = dis / nearDis;
        }
       
        vec4 viewPosition = modelViewMatrix * vec4(position, 1.0);
        gl_Position = projectionMatrix * viewPosition;
    }
    `,
    fragmentShader: `
    varying vec2 vUv;
    varying float opacity;

    void main() {

        vec3 color = vec3(vUv.y,vUv.y,1.);

        gl_FragColor = vec4(color, opacity);
    }

    `,
});

const plane = new THREE.Mesh(
        new THREE.PlaneGeometry(1, 1, 100, 100),
        // new THREE.BoxGeometry(1, 1, 1, 10, 10, 10),
        customShader
        // material
    );

const plane = new THREE.Mesh(
     // new THREE.PlaneGeometry(1, 1, 200, 200),
     new THREE.BoxGeometry(1, 1, 1, 10, 10, 10),
     stripeShader
     // material
 );
 helper.add(plane);
 
/**
 * 离相机进的点 条纹展示
 */
const stripeShader = new THREE.ShaderMaterial({
    uniforms: {},
    defines: { nearDis: 1.01 },
    side: THREE.DoubleSide,
    vertexShader: `
    varying vec2 vUv;
    varying vec3 vPos;
    varying float opacity;

    void main() {
        vUv = uv;
        vPos = position;
        float dis = distance(position,cameraPosition);
        opacity = 1.0;
        if(dis < nearDis){
            opacity = 0.;
        }

        vec4 viewPosition = modelViewMatrix * vec4(position, 1.0);
        gl_Position = projectionMatrix * viewPosition;
    }
    `,
    fragmentShader: `
    varying vec2 vUv;
    varying vec3 vPos;
    varying float opacity;

    void main() {

        vec3 color = vec3(vUv.y,vUv.y,1.);

        if(opacity != 1.){
            if(mod(floor(vPos.y /  0.01),2.0) == 0.0){
                discard;
            }
        }

        

        gl_FragColor = vec4(color, 1.);
    }

    `,
});