使用 Three.js 创建边缘模糊效果，使用自定义着色器实现图像边缘的渐变透明效果。

precision highp float;
precision highp int;
uniform mat4 modelViewMatrix;
uniform mat4 projectionMatrix;
attribute vec3 position;
attribute vec2 uv;
varying vec2 vUv;
void main() {
    vUv = uv;
    gl_Position = projectionMatrix * modelViewMatrix * vec4(position, 1.0);
}

precision highp float;
precision highp int;

uniform float edge;
uniform float opacity;
uniform sampler2D map;
varying vec2 vUv;

void main(){
    float edgeMin = edge;
    float edgeMax = 1.0 - edge;

    gl_FragColor = texture2D(map, vUv);

    if(vUv.x < edgeMin){
        if(vUv.y < edgeMin){
            gl_FragColor.a = (min(vUv.x / edgeMin, vUv.y / edgeMin)) * opacity;
        }
        else if(vUv.y >= edgeMin && vUv.y <= edgeMax){
            gl_FragColor.a = (vUv.x / edgeMin) * opacity;
        }
        else if(vUv.y > edgeMax){
            gl_FragColor.a = (min(vUv.x / edgeMin, 1.0 - ((vUv.y - edgeMax) / edgeMin))) * opacity;
        }
    }
    else if(vUv.x >= edgeMin && vUv.x <= edgeMax){
        if(vUv.y < edgeMin){
            gl_FragColor.a = (vUv.y / edgeMin) * opacity;
        }
        else if(vUv.y >= edgeMin && vUv.y <= edgeMax){
            gl_FragColor.a = 1.0 * opacity;
        }
        else if(vUv.y > edgeMax){
            gl_FragColor.a = (1.0 - ((vUv.y - edgeMax) / edgeMin)) * opacity;
        }
    }
    else if(vUv.x > edgeMax){
        float xNormal = 1.0 - ((vUv.x - edgeMax) / edgeMin);
        
        if(vUv.y < edgeMin){
            gl_FragColor.a = (min(vUv.y / edgeMin, xNormal)) * opacity;
        }
        else if(vUv.y >= edgeMin && vUv.y <= edgeMax){
            gl_FragColor.a = (xNormal) * opacity;
        }
        else if(vUv.y > edgeMax){
            gl_FragColor.a = (min(xNormal, 1.0 - ((vUv.y - edgeMax) / edgeMin))) * opacity;
        }
    }
}

const material = new THREE.RawShaderMaterial({
    uniforms: UniformsUtils.clone({
        map: { type: "t", value: null },
        edge: { type: "float", value: 0.1 },
        opacity: { type: "float", value: 1 },
    }),
    transparent: true,
    opacity: 1,
    alphaTest: 1,
    depthTest: true,
    vertexShader: vertexShader,
    fragmentShader: fragmentShader,
});