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我试图在 three.js 中使用两个以上的贴图通道来为我的模型分配纹理。令我惊讶的是，three.js 中没有原生材质支持多组 uv。因此，我必须使用 ShaderMaterial 并编写自己的顶点/片段着色器才能访问多个贴图通道。

现在我确实设法让多通道 uvs 使用我写的一个简单代码：

<script id="vertex_shh" type="x-shader/x-vertex">

    //VERTEX SHADER//

        varying vec2 vUv;
        attribute vec2 uv2;
        varying vec2 vUv2;
        attribute vec2 uv3;
        varying vec2 vUv3;
        attribute vec2 uv4;
        varying vec2 vUv4;
        attribute vec2 uv5;
        varying vec2 vUv5;


        void main()
        {
            vUv = uv;
            vUv2 = uv2;
            vUv3 = uv3;
            vUv4 = uv4;
            vUv5 = uv5;                 

            vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );
            gl_Position = projectionMatrix * mvPosition;
        }

    // END //

    </script>       



    <script id="fragment_shh" type="x-shader/x-fragment">   

    //FRAGMENT SHADER//

        uniform sampler2D tCh1;
        uniform sampler2D tCh2;
        uniform sampler2D tCh3;
        uniform sampler2D tCh4;         
        uniform sampler2D tCh5;

        varying vec2 vUv;
        varying vec2 vUv2;
        varying vec2 vUv3;
        varying vec2 vUv4;
        varying vec2 vUv5;


        void main(void)
        {
            vec3 DiffuseComp;
            vec4 TexCh1 = texture2D(tCh1, vUv);
            vec4 TexCh2 = texture2D(tCh2, vUv2);
            vec4 TexCh3 = texture2D(tCh3, vUv3);
            vec4 TexCh4 = texture2D(tCh4, vUv4);
            vec4 TexCh5 = texture2D(tCh5, vUv5);

            DiffuseComp = ((TexCh1.rgb * (1.0 - TexCh4.rgb) + (TexCh2.rgb * TexCh4.rgb)) * (1.0 - TexCh5.rgb)) + (TexCh3.rgb * TexCh5.rgb);
            gl_FragColor= vec4(DiffuseComp, 1.0);   
        }

    // END //

        /* SHADER */
        var vertShader = document.getElementById('vertex_shh').innerHTML;
        var fragShader = document.getElementById('fragment_shh').innerHTML;

        var attributes = {};

        var uniforms = {
        tCh1: { type: "t", value: Textura1},
        tCh2: { type: "t", value: Textura2},
        tCh3: { type: "t", value: Textura3},
        tCh4: { type: "t", value: Textura4},
        tCh5: { type: "t", value: Textura5}
        };          


        /* MATERIAL */
        var multitexsh = new THREE.ShaderMaterial({
        uniforms: uniforms,
        attributes: attributes,
        vertexShader: vertShader,
        fragmentShader: fragShader
        });

然而，我的问题是我基本上需要一个具有此功能的着色器和 Phong 着色器的一些基本特性：照明（来自场景灯光）和镜面高光。我完全迷失在这里。我已经尝试寻找方法来将此功能添加到本机着色器或将上述功能从 phong 材质添加到我自己的着色器，但没有发现任何信息足以用我非常基本的编码技能做到这一点.. 任何人都可以进来帮帮我吗？

编辑：

感谢pailhead让它与 onBeforeCompile 一起工作。这是在 r89 上，更新代码如下：

        /* MANAGERS, LOADERS */
        var manager = new THREE.LoadingManager();
        var loader = new THREE.FBXLoader( manager );
        var textureLoader = new THREE.TextureLoader( manager );

        /*TEXTURE */
        var prodtex ='textures/testing/cubetex.jpg';
        var prodtex2 ='textures/testing/cube_blendmap.jpg';

        var Textura1 = textureLoader.load (prodtex);
        var Textura2 = textureLoader.load (prodtex);
        var Textura3 = textureLoader.load (prodtex2);

        /* MATERIAL */
        var MAT = new THREE.MeshPhongMaterial();
        MAT.map = Textura1;     

        /* MY SHADER CHANGES*/
        const uv2_chunkToReplaceVS = 'attribute vec2 uv2; varying vec2 vUv2; attribute vec2 uv3; varying vec2 vUv3;'
        const uv2_chunkToReplaceVSV = 'vUv2 = uv2; vUv3 = uv3;'
        const uv2_chunkToReplaceFS = 'uniform sampler2D tCh1; uniform sampler2D tCh2; uniform sampler2D tCh3; varying vec2 vUv2; varying vec2 vUv3;'
        const map_chunkToReplaceFSV = 'vec4 TexCh1 = texture2D(tCh1, vUv); vec4 TexCh2 = texture2D(tCh2, vUv2); vec4 TexCh3 = texture2D(tCh3, vUv3); vec4 texelColor = texture2D( map, vUv ); texelColor = mapTexelToLinear( texelColor ); TexCh1 = mapTexelToLinear( TexCh1 ); TexCh2 = mapTexelToLinear( TexCh2 ); TexCh2 = mapTexelToLinear( TexCh2 ); diffuseColor *= TexCh1 * (1.0 - TexCh3) + (TexCh2 * TexCh3);'

        MAT.onBeforeCompile = shader=>{
        shader.uniforms.tCh1= {type: "t", value: Textura1};
        shader.uniforms.tCh2= {type: "t", value: Textura2};
        shader.uniforms.tCh3= {type: "t", value: Textura3};

        shader.fragmentShader = shader.fragmentShader.replace('#include <map_fragment>', map_chunkToReplaceFSV);
        shader.vertexShader = shader.vertexShader.replace('#include <uv2_pars_vertex>', uv2_chunkToReplaceVS );
        shader.vertexShader = shader.vertexShader.replace('#include <uv2_vertex>', uv2_chunkToReplaceVSV );
        shader.fragmentShader = shader.fragmentShader.replace('#include <uv2_pars_fragment>', uv2_chunkToReplaceFS);
        };


        /* MODEL */
        loader.load( ('models/' + 'cube' + '.FBX'), function( object ) {
            //set material//
            object.traverse( function ( child ) {
                if ( child instanceof THREE.Mesh ) {
                    child.material = MAT;
                };
            } );                
            scene.add (object);
        });
4

1 回答 1

1

您可以使用材料的未记录功能，称为onBeforeCompile.

它是在三个解析着色器模板之前和编译着色器之前调用的回调。

模板可能如下所示

//someTemplate.vert

#include <common>
#include <some_pars_vertex>

void main(){
  #include <some_vertex>
  #include <another_vertex>

  gl_Position = projectionMatrix * foobar;
}

假设您要添加更多 uv 通道。你会在 GLSL 中创建一些片段/函数。这必须在全局范围内发生（上图void main(){...}）：

//myBeforeVoidMain.vert

attribute vec2 aUV2;
attribute vec2 aUV3;

varying vec2 vUv2;
varying vec2 vUv3;

然后这必须发生在主函数中：

//myUv.vert
vUv2 = aUV2;
vUv3 = aUV3;

您可以注入此代码，但在哪里以及如何注入？

如何：

const chunkToReplace = THREE.ShaderChunk.uv_pars_vertex

myMaterial = new THREE.MeshPhongMaterial()
myMaterial.onBeforeCompile( shader=>{
  shader.uniforms.myUniform = {value:foo} 
  shader.vertexShader = shader.vertexShader.replace( '#include <uv_pars_vertex>', chunkToReplace + myChunk )
})

在哪里：

您需要熟悉两者： https ://github.com/mrdoob/three.js/tree/dev/src/renderers/shaders/ShaderChunk https://github.com/mrdoob/three.js/tree/dev /src/renderers/shaders/ShaderLib

你需要考虑一下。可以注意到它<common>几乎存在于每个库的全局范围内。但是，因为它包含在 vert 和 frag 着色器中，所以不能在其中提及attribute，所以 frag 着色器将无法编译。

向顶点着色器添加属性、统一和变量的一个好块是uv_pars_vertex因为它也存在于几乎所有着色器中。

对于这个特殊问题，您还必须扩展片段着色器。再次将变量放置在 中uv_pars_fragment，然后您必须找到将使用这些 uv 通道的其余逻辑。

笔记：

将两个通道打包到一个属性中可能是个好主意：

attribute vec4 aUv23;

...
  vUv2 = aUv23.xy;
  vUv3 = aUv23.zw;
于 2018-01-24T00:13:53.093 回答