使用 ShaderMaterial 复制 MeshLambertMaterial 会忽略纹理

我注意到 THREE.js 在内部使用着色器来创建核心材质“例如 MeshLambertMaterial”，因此我决定将 Three.js 代码中的兰伯特着色器复制到新的着色器中并在其上进行构建。

这是我得到的代码（忠实地从 Three.js r66 复制）

THREE.MyShader = {

uniforms: THREE.UniformsUtils.merge( [
    THREE.UniformsLib[ "common" ],
    THREE.UniformsLib[ "fog" ],
    THREE.UniformsLib[ "lights" ],
    THREE.UniformsLib[ "shadowmap" ],
    {
        "ambient"  : { type: "c", value: new THREE.Color( 0xffffff ) },
        "emissive" : { type: "c", value: new THREE.Color( 0x000000 ) },
        "wrapRGB"  : { type: "v3", value: new THREE.Vector3( 1, 1, 1 ) }
    }
]),

vertexShader: [

    "#define LAMBERT",

    "varying vec3 vLightFront;",

    "#ifdef DOUBLE_SIDED",

        "varying vec3 vLightBack;",

    "#endif",

    THREE.ShaderChunk[ "map_pars_vertex" ],
    THREE.ShaderChunk[ "lightmap_pars_vertex" ],
    THREE.ShaderChunk[ "envmap_pars_vertex" ],
    THREE.ShaderChunk[ "lights_lambert_pars_vertex" ],
    THREE.ShaderChunk[ "color_pars_vertex" ],
    THREE.ShaderChunk[ "morphtarget_pars_vertex" ],
    THREE.ShaderChunk[ "skinning_pars_vertex" ],
    THREE.ShaderChunk[ "shadowmap_pars_vertex" ],

    "void main() {",

        THREE.ShaderChunk[ "map_vertex" ],
        THREE.ShaderChunk[ "lightmap_vertex" ],
        THREE.ShaderChunk[ "color_vertex" ],

        THREE.ShaderChunk[ "morphnormal_vertex" ],
        THREE.ShaderChunk[ "skinbase_vertex" ],
        THREE.ShaderChunk[ "skinnormal_vertex" ],
        THREE.ShaderChunk[ "defaultnormal_vertex" ],

        THREE.ShaderChunk[ "morphtarget_vertex" ],
        THREE.ShaderChunk[ "skinning_vertex" ],
        THREE.ShaderChunk[ "default_vertex" ],

        THREE.ShaderChunk[ "worldpos_vertex" ],
        THREE.ShaderChunk[ "envmap_vertex" ],
        THREE.ShaderChunk[ "lights_lambert_vertex" ],
        THREE.ShaderChunk[ "shadowmap_vertex" ],

    "}"

].join("\n"),

fragmentShader: [

    "uniform float opacity;",

    "varying vec3 vLightFront;",

    "#ifdef DOUBLE_SIDED",

        "varying vec3 vLightBack;",

    "#endif",

    THREE.ShaderChunk[ "color_pars_fragment" ],
    THREE.ShaderChunk[ "map_pars_fragment" ],
    THREE.ShaderChunk[ "lightmap_pars_fragment" ],
    THREE.ShaderChunk[ "envmap_pars_fragment" ],
    THREE.ShaderChunk[ "fog_pars_fragment" ],
    THREE.ShaderChunk[ "shadowmap_pars_fragment" ],
    THREE.ShaderChunk[ "specularmap_pars_fragment" ],



    "void main() {",

        "gl_FragColor = vec4( vec3 ( 1.0 ), opacity );",

        THREE.ShaderChunk[ "map_fragment" ],
        THREE.ShaderChunk[ "alphatest_fragment" ],
        THREE.ShaderChunk[ "specularmap_fragment" ],

        "#ifdef DOUBLE_SIDED",

            //"float isFront = float( gl_FrontFacing );",
            //"gl_FragColor.xyz *= isFront * vLightFront + ( 1.0 - isFront ) * vLightBack;",

            "if ( gl_FrontFacing )",
                "gl_FragColor.xyz *= vLightFront;",
            "else",
                "gl_FragColor.xyz *= vLightBack;",

        "#else",

            "gl_FragColor.xyz *= vLightFront;",

        "#endif",

        THREE.ShaderChunk[ "lightmap_fragment" ],
        THREE.ShaderChunk[ "color_fragment" ],
        THREE.ShaderChunk[ "envmap_fragment" ],
        THREE.ShaderChunk[ "shadowmap_fragment" ],

        THREE.ShaderChunk[ "linear_to_gamma_fragment" ],

        THREE.ShaderChunk[ "fog_fragment" ],

    "}"

].join("\n")

}

这是我用来设置制服和创建材质的代码。

var textureUsed = 'rock_1';
var texture = THREE.ImageUtils.loadTexture( texturePath + textureUsed + "/diffuse.png");
texture.wrapS   = THREE.RepeatWrapping;
texture.wrapT   = THREE.RepeatWrapping;
texture.repeat.x = 128;
texture.repeat.y = 128;
var shaderUniforms = THREE.UniformsUtils.clone( THREE.MyShader.uniforms );
shaderUniforms[ "map" ].value = texture;
var material =  new THREE.ShaderMaterial({
                    name: "TerrainShader",
                    uniforms    : shaderUniforms,
                    vertexShader: THREE.MyShader.vertexShader,
                    fragmentShader: THREE.MyShader.fragmentShader,
                    fog:false,
                    lights:true
                });

问题是，当我使用这些参数创建 MeshLambertMaterial 时，我得到了正确的照明和纹理重复，当我使用它创建 ShaderMaterial 时，灯光和阴影似乎正在工作，但纹理贴图未加载，要解决此问题，我深入研究代码并设法通过在材质定义之后将这个丑陋的“黑客”添加到我的代码中来加载地图

material.map = true;

现在纹理已加载并显示，但看起来纹理坐标被搞乱了，着色器似乎忽略了我提供的重复值，而不是重复。

为什么我需要这个技巧来处理我的纹理以及我可以做什么来获得正确的纹理重复？

Three.js 被设计为易于使用，而不是易于修改。这在未来可能会改变......

您需要设置material.defines像这样：

var defines = {};

defines[ "USE_MAP" ] = "";. 

然后指定defines在材质构造函数中。

var material =  new THREE.ShaderMaterial({
   name: "TerrainShader",
   defines     : defines,
   uniforms    : shaderUniforms,
   vertexShader: THREE.MyShader.vertexShader,
   fragmentShader: THREE.MyShader.fragmentShader,
   fog:false,
   lights:true
});

关于纹理重复，您需要将重复添加到您的制服中：

shaderUniforms[ "offsetRepeat" ].value.set( 0, 0, 2, 2 );

三.js r.66