可以在three.js几何图形中使用Vector4吗？

Question

I'm currently getting to know the three.js library. The coordinates that are stored in a mesh's geometry are tuples (x,y,z). However, when doing affine transformations behind the scenes, the graphics card uses tuples (x,y,z,w) and encodes the transformations as 4x4-matrices.

Can I store vertices explicitly as tuples (x,y,z,w) in three.js?

I don't want the value of w to always be 1. (Yes, this is a slightly strange request, and I'm fully aware that (x,y,z,w) can always be rescaled so as to make w=1. However, the application that I have in mind requires that I store my vertices as 4-tuples and that I can set all 4 coordinates.)

I don't feel like digging into raw WebGL if I can use three.js.

Answer 1

I think you should be able to just do this...

var positions = new THREE.Float32Attribute( triangles * 3, 4 );
var geometry = new THREE.BufferGeometry();
geometry.addAttribute( 'position', positions );

positions.array will then be an array like [ x, y, z, w, x, y, z, w, ... ]

r67+