Question

我正在尝试将天空盒分配给播放器相机。当相机移动时（天空箱随之移动），纹理会变得拉长。如何摆脱这个？

代码：

var textureCube = THREE.ImageUtils.loadTextureCube( urls );
textureCube.format = THREE.RGBFormat;
var shader = THREE.ShaderUtils.lib[ "cube" ];
shader.uniforms[ "tCube" ].value = textureCube;

cubematerial = new THREE.ShaderMaterial({
    fragmentShader: shader.fragmentShader,
    vertexShader: shader.vertexShader,
    uniforms: shader.uniforms,
    depthWrite: false,
    side: THREE.BackSide
});
skyBox = new THREE.Mesh(new THREE.CubeGeometry(1000,1000,1000), cubematerial);
camera.add(skyBox);

Answer 1

因此，在深入研究Three.js示例之后，我找到了一种方法。 http://learningthreejs.com/blog/2011/08/15/lets-do-a-sky/已过时。示例中使用的方法是使用固定摄像头将天空盒添加到第二个场景中，并渲染两个场景。请查看webgl_materials_cars.html示例。

另外，因为我使用分配给角色的第三人称相机，我必须从角色相机到天空盒相机进行世界旋转。这可以在渲染时完成：

function render(){
<...>
    skyboxCamera.rotation.setEulerFromRotationMatrix( new THREE.Matrix4().extractRotation( camera.matrixWorld ), skyboxCamera.eulerOrder );
    renderer.render(skyboxScene, skyboxCamera);
    renderer.render(scene, camera);
<...>
}

Answer 2

我知道这是一个封闭的问题，但我想为未来的寻求者提供一个不需要额外场景的替代方案：

首先阅读并阅读本教程：http://learningthreejs.com/blog/2011/08/15/lets-do-a-sky/

现在创建以下着色器（我将其添加到three.js ShaderLib中，但如果您不想用三个源代码添加它，请将其添加到外部）：

'skybox': {

uniforms: { "tCube": { type: "t", value: null },
            "tFlip": { type: "f", value: -1 } },

vertexShader: [

    "varying vec3 vWorldPosition;",

    THREE.ShaderChunk[ "logdepthbuf_pars_vertex" ],

    "void main() {",

    "   vec4 worldPosition = modelMatrix * vec4( position, 1.0 );",
    "   vWorldPosition = worldPosition.xyz;",

    "   gl_Position = projectionMatrix * modelViewMatrix * vec4( position + cameraPosition, 1.0 );",

        THREE.ShaderChunk[ "logdepthbuf_vertex" ],

    "}"

].join("\n"),

fragmentShader: [

    "uniform samplerCube tCube;",
    "uniform float tFlip;",

    "varying vec3 vWorldPosition;",

    THREE.ShaderChunk[ "logdepthbuf_pars_fragment" ],

    "void main() {",

    "   gl_FragColor = textureCube( tCube, vec3( tFlip * vWorldPosition.x, vWorldPosition.yz ) );",

        THREE.ShaderChunk[ "logdepthbuf_fragment" ],

    "}"

].join("\n")

}，

像这样创建你的天空盒：

    // urls is a list of textures to use
var cubemap = THREE.ImageUtils.loadTextureCube(urls); 
cubemap.format = THREE.RGBFormat; 

var shader = THREE.ShaderLib['skybox']; // init the skybox shader we created above
shader.uniforms['tCube'].value = cubemap; // apply textures to shader

// create shader material
var skyBoxMaterial = new THREE.ShaderMaterial( {
  fragmentShader: shader.fragmentShader,
  vertexShader: shader.vertexShader,
  uniforms: shader.uniforms,
  depthWrite: false,
  side: THREE.BackSide
});

// create skybox mesh
var skybox = new THREE.Mesh(
  new THREE.CubeGeometry(1000, 1000, 1000),
  skyBoxMaterial
);

        // THIS IS IMPORTANT! or the skybox will get culled after you move the camera too far..
skybox.frustumCulled = false;

three.js skybox分配给相机

2 个答案: