pub fn generate_grid_indices(nu: u32, nv: u32) -> Vec<u32>Expand description
Generate triangle indices for a nu × nv grid of vertices (row-major layout).
Each quad [i, j] → 2 triangles: [tl, bl, tr] and [tr, bl, br]
where tl = i*nv + j, tr = i*nv + j+1, bl = (i+1)*nv + j, br = (i+1)*nv + j+1.
Total index count = 6 * (nu - 1) * (nv - 1).