javascript - 使用 ShaderMaterial 复制 MeshLambertMaterial 忽略纹理

Question

我注意到 THREE.js 在内部使用着色器来创建核心 Material “例如 MeshLambertMaterial”，因此我决定将 Lambert 着色器从 Three.js 代码复制到一个新的着色器中并在其上构建。

这是我得到的代码(忠实地从 Three.js r66 复制而来)

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 Material 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，灯光和阴影似乎有效但未加载纹理贴图，以解决这个问题我仔细研究了代码，并通过在 Material 定义之后立即向我的代码中添加这个丑陋的“hack”来设法加载 map

material.map = true;

现在纹理已加载并显示，但纹理坐标看起来乱七八糟，着色器似乎忽略了我提供的重复值，而不是重复。

为什么我需要那个 hack 来处理我的纹理，我该怎么做才能获得正确的纹理重复？

Answer 1

three.js 旨在易于使用，不易修改。这在未来可能会改变......

您需要像这样设置material.defines:

var defines = {};

defines[ "USE_MAP" ] = "";. 

然后在 Material 构造函数中指定defines。

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 );

three.js r.66