Three.js - Adding texture to custom geometry

Question

I'm working on applying a simple material with a texture map to a custom mesh. I couldn't find any examples that I could understand, so I made this fiddle to demonstrate what I'm trying to achieve.

/// MATERIAL
var texture = new THREE.TextureLoader().load( "https://raw.githubusercontent.com/mrdoob/three.js/master/examples/textures/crate.gif" );
var material = new THREE.MeshBasicMaterial( { 
    map: texture,
  side: THREE.DoubleSide
} );

// TRIANGLE
var geometry2 = new THREE.Geometry();
var v1 = new THREE.Vector3(0,200,0);
var v2 = new THREE.Vector3(0,0,-100);
var v3 = new THREE.Vector3(0,0,100);
geometry2.vertices.push(v1);
geometry2.vertices.push(v2);
geometry2.vertices.push(v3);
geometry2.faces.push( new THREE.Face3( 0, 1, 2 ) );
meshCustom = new THREE.Mesh(geometry2, material);
scene.add(meshCustom);

// CUBE
var geometry = new THREE.BoxBufferGeometry( 100, 100, 100 );
mesh = new THREE.Mesh( geometry, material );
scene.add( mesh );

https://jsfiddle.net/benaloney/L7js807k/8/

I just want the triangle to have the same texture as the cube, I understand there needs to be UV coordinates on the mesh for this to work, but am unsure of how to implement this.

Answer 1

The texture on the triangle looks weird though... Just in case, adapting the UVs to your actual object might help :

Your updated fiddle

Here's how :

//texture
    var texture2 = new THREE.TextureLoader().load( "https://raw.githubusercontent.com/mrdoob/three.js/master/examples/textures/crate.gif" );


//material
    var material2 = new THREE.MeshBasicMaterial( { 
        map: texture2,
      side: THREE.DoubleSide
    } );

  // TRIANGLE
    var geometry2 = new THREE.Geometry();
    var v1 = new THREE.Vector3(0,200,0);
    var v2 = new THREE.Vector3(0,0,-100);
    var v3 = new THREE.Vector3(0,0,100);
    geometry2.vertices.push(v1);
    geometry2.vertices.push(v2);
    geometry2.vertices.push(v3);
    geometry2.faces.push( new THREE.Face3( 0, 1, 2 ) );

//manually setting your UVs
    geometry2.faceVertexUvs[0].push([
            new THREE.Vector2(0,0),        //play with these values
            new THREE.Vector2(0.5,0),
            new THREE.Vector2(0.5,0.5)
        ]);

//updating the uvs
    geometry2.uvsNeedUpdate = true;

Answer 2

Got it working, so I did need UV coordinates on the Geometry. Thanks to this other question:

https://stackoverflow.com/a/27317936/2419584

I added this function and passed the geometry through it.

function assignUVs(geometry) {
    geometry.faceVertexUvs[0] = [];
    geometry.faces.forEach(function(face) {
        var components = ['x', 'y', 'z'].sort(function(a, b) {
            return Math.abs(face.normal[a]) > Math.abs(face.normal[b]);
        });

        var v1 = geometry.vertices[face.a];
        var v2 = geometry.vertices[face.b];
        var v3 = geometry.vertices[face.c];

        geometry.faceVertexUvs[0].push([
            new THREE.Vector2(v1[components[0]], v1[components[1]]),
            new THREE.Vector2(v2[components[0]], v2[components[1]]),
            new THREE.Vector2(v3[components[0]], v3[components[1]])
        ]);

    });
    geometry.uvsNeedUpdate = true;
}

This automatically generates the UV coords, from the geometry, this then allows textures with images to show up on custom geometries.

Here is my updated working jsfiddle.

https://jsfiddle.net/benaloney/L7js807k/9/