var material = new three.ShaderMaterial({ uniforms: { panorama: { value: new three.Texture(), }, resolution: { value: 2.0, }, transform: { value: new three.Matrix4(), }, zoom: { value: 10.0, }, opacity: { value: 1.0, }, }, vertexShader: "\nvarying vec2 vUv;\n\nvoid main() {\n vUv = uv;\n gl_Position = vec4( position, 1.0 );\n}", fragmentShader: "\nuniform sampler2D panorama;\nuniform float resolution;\nuniform mat4 transform;\nuniform float zoom;\nuniform float opacity;\n\nvarying vec2 vUv;\n\nconst float PI = 3.1415926535897932384626433832795;\n\nvoid main() {\n vec2 position = -1.0 + 2.0 * vUv;\n position *= vec2( zoom * resolution, zoom * 0.5 );\n\n float x2y2 = position.x * position.x + position.y * position.y;\n vec3 sphere_pnt = vec3( 2. * position, x2y2 - 1. ) / ( x2y2 + 1. );\n sphere_pnt = vec3( transform * vec4( sphere_pnt, 1.0 ) );\n\n vec2 sampleUV = vec2(\n 1.0 - (atan(sphere_pnt.y, sphere_pnt.x) / PI + 1.0) * 0.5,\n (asin(sphere_pnt.z) / PI + 0.5)\n );\n\n gl_FragColor = texture2D( panorama, sampleUV );\n gl_FragColor.a *= opacity;\n}", });

这段代码是用于创建一个three.js中的ShaderMaterial材质，该材质使用了自定义的顶点着色器和片元着色器。其中uniforms中定义了五个变量：panorama、resolution、transform、zoom、opacity，分别代表全景图、分辨率、变换矩阵、缩放比例和透明度。顶点着色器中将uv坐标传递给片元着色器。片元着色器中将uv坐标转换成全景图上的点位置，使用该位置对全景图进行采样，并将透明度乘以gl_FragColor的alpha通道。