I have come across BufferGeometryUtils in the example directory of three.js, which allows for converting existing geometries to buffer geometry without the need to refactor all my code for performance improvement. I am wondering how I can declare this function in three.d.ts file.
/**
* @author spite / http://www.clicktorelease.com/
* @author mrdoob / http://mrdoob.com/
*/
THREE.BufferGeometryUtils = {
fromGeometry: function geometryToBufferGeometry( geometry, settings ) {
if ( geometry instanceof THREE.BufferGeometry ) {
return geometry;
}
settings = settings || { 'vertexColors': THREE.NoColors };
var vertices = geometry.vertices;
var faces = geometry.faces;
var faceVertexUvs = geometry.faceVertexUvs;
var vertexColors = settings.vertexColors;
var hasFaceVertexUv = faceVertexUvs[ 0 ].length > 0;
var bufferGeometry = new THREE.BufferGeometry();
bufferGeometry.attributes = {
position: {
itemSize: 3,
array: new Float32Array( faces.length * 3 * 3 )
},
normal: {
itemSize: 3,
array: new Float32Array( faces.length * 3 * 3 )
}
}
var positions = bufferGeometry.attributes.position.array;
var normals = bufferGeometry.attributes.normal.array;
if ( vertexColors !== THREE.NoColors ) {
bufferGeometry.attributes.color = {
itemSize: 3,
array: new Float32Array( faces.length * 3 * 3 )
};
var colors = bufferGeometry.attributes.color.array;
}
if ( hasFaceVertexUv === true ) {
bufferGeometry.attributes.uv = {
itemSize: 2,
array: new Float32Array( faces.length * 3 * 2 )
};
var uvs = bufferGeometry.attributes.uv.array;
}
var i2 = 0, i3 = 0;
for ( var i = 0; i < faces.length; i ++ ) {
var face = faces[ i ];
var a = vertices[ face.a ];
var b = vertices[ face.b ];
var c = vertices[ face.c ];
positions[ i3 ] = a.x;
positions[ i3 + 1 ] = a.y;
positions[ i3 + 2 ] = a.z;
positions[ i3 + 3 ] = b.x;
positions[ i3 + 4 ] = b.y;
positions[ i3 + 5 ] = b.z;
positions[ i3 + 6 ] = c.x;
positions[ i3 + 7 ] = c.y;
positions[ i3 + 8 ] = c.z;
var na = face.vertexNormals[ 0 ];
var nb = face.vertexNormals[ 1 ];
var nc = face.vertexNormals[ 2 ];
normals[ i3 ] = na.x;
normals[ i3 + 1 ] = na.y;
normals[ i3 + 2 ] = na.z;
normals[ i3 + 3 ] = nb.x;
normals[ i3 + 4 ] = nb.y;
normals[ i3 + 5 ] = nb.z;
normals[ i3 + 6 ] = nc.x;
normals[ i3 + 7 ] = nc.y;
normals[ i3 + 8 ] = nc.z;
if ( vertexColors === THREE.FaceColors ) {
var fc = face.color;
colors[ i3 ] = fc.r;
colors[ i3 + 1 ] = fc.g;
colors[ i3 + 2 ] = fc.b;
colors[ i3 + 3 ] = fc.r;
colors[ i3 + 4 ] = fc.g;
colors[ i3 + 5 ] = fc.b;
colors[ i3 + 6 ] = fc.r;
colors[ i3 + 7 ] = fc.g;
colors[ i3 + 8 ] = fc.b;
} else if ( vertexColors === THREE.VertexColors ) {
var vca = face.vertexColors[ 0 ];
var vcb = face.vertexColors[ 1 ];
var vcc = face.vertexColors[ 2 ];
colors[ i3 ] = vca.r;
colors[ i3 + 1 ] = vca.g;
colors[ i3 + 2 ] = vca.b;
colors[ i3 + 3 ] = vcb.r;
colors[ i3 + 4 ] = vcb.g;
colors[ i3 + 5 ] = vcb.b;
colors[ i3 + 6 ] = vcc.r;
colors[ i3 + 7 ] = vcc.g;
colors[ i3 + 8 ] = vcc.b;
}
if ( hasFaceVertexUv === true ) {
var uva = faceVertexUvs[ 0 ][ i ][ 0 ];
var uvb = faceVertexUvs[ 0 ][ i ][ 1 ];
var uvc = faceVertexUvs[ 0 ][ i ][ 2 ];
uvs[ i2 ] = uva.x;
uvs[ i2 + 1 ] = uva.y;
uvs[ i2 + 2 ] = uvb.x;
uvs[ i2 + 3 ] = uvb.y;
uvs[ i2 + 4 ] = uvc.x;
uvs[ i2 + 5 ] = uvc.y;
}
i3 += 9;
i2 += 6;
}
bufferGeometry.computeBoundingSphere();
return bufferGeometry;
}
}