Three JS Map Material causes WebGL Warning

问题

I'm trying to define a material to meshes I loaded in from OBJLoader through the following wrapper function:

function applyTexture(src){
    var texture = new THREE.Texture();
    var loader = new THREE.ImageLoader();
    loader.addEventListener( 'load', function ( event ) {
        texture.image = event.content;
        texture.needsUpdate = true;

        // find the meshes from the loaded OBJ and apply the texture to it.
        object.traverse( function ( child ) {
            if ( child instanceof THREE.Mesh ) {
                if(child.name.indexOf("Lens") < 0){
                    child.dynamic = true;

                   child.material = new THREE.MeshLambertMaterial( { color: 0xdddddd, shading: THREE.FlatShading, map : texture } );
                   // also tried:
                   //child.material = new THREE.MeshPhongMaterial( { color: 0x000000, specular: 0x666666, emissive: 0x000000, ambient: 0x000000, shininess: 10, shading: THREE.SmoothShading, map : texture} );
                   // and:
                   //child.material = new THREE.MeshBasicMaterial({map : texture});
                   child.material.map = texture; // won't throw the WebGL Warning, but won't show the texture either;
               } else {
                   // works just fine.
                   child.material = new THREE.MeshPhongMaterial( { color: 0x000000, specular: 0x666666, emissive: 0x000011, ambient: 0x000000, shininess: 10, shading: THREE.SmoothShading, opacity: 0.6, transparent: true } );
               }
            }
        });
    });
    loader.load( src );
}

When the texture has loaded and it's time to apply the material to the mesh, I start getting the following warning on the console:

.WebGLRenderingContext: GL ERROR :GL_INVALID_OPERATION : glDrawElements: attempt to access out of range vertices in attribute 0 

and the mesh itself disappears.

what am I doing wrong here?

UPDATE

As @WestLangley pointed on the comments: Never try to apply texture/materials after things have been rendered. Create the materials before rendering the object to the scene and then change them using:

obj.material.map = texture

回答1:

With WebGLRenderer, you can't switch from a material without a texture, to a material with a texture, after the mesh has been rendered once. This is because, without an initial texture, the geometry will not have the necessary baked-in WebGL UV buffers.

A work-around is to begin with a material having a simple white texture.

UPDATE: Alternatively, you can begin with a textureless material, and then set the following flags when a texture is added:

material.needsUpdate = true;
geometry.buffersNeedUpdate = true;
geometry.uvsNeedUpdate = true;

three.js r.58

回答2:

I also got this error while loading a scene from blender. For me the problem was fixed when unwrapping the uv's for each mesh i want to have a texture on.

来源：https://stackoverflow.com/questions/16531759/three-js-map-material-causes-webgl-warning