Function push_triangle

perro_source/core/perro_builtin_meshes/src/lib.rs:426–462

(
    vertices: &mut Vec<BuiltinMeshVertex>,
    indices: &mut Vec<u16>,
    a: [f32; 3],
    b: [f32; 3],
    c: [f32; 3],
)

}

fn push_triangle(
    vertices: &mut Vec<BuiltinMeshVertex>,
    indices: &mut Vec<u16>,
    a: [f32; 3],
    b: [f32; 3],
    c: [f32; 3],
) {
    let av = a;
    let mut bv = b;
    let mut cv = c;
    let mut normal = normalize3(cross3(sub3(bv, av), sub3(cv, av)));
    let centroid = scale3(add3(add3(av, bv), cv), 1.0 / 3.0);
    if dot3(normal, centroid) < 0.0 {
        std::mem::swap(&mut bv, &mut cv);
        normal = normalize3(cross3(sub3(bv, av), sub3(cv, av)));
    }
    let auv = project_uv(a, normal);
    let buv = project_uv(bv, normal);
    let cuv = project_uv(cv, normal);
    let base = vertices.len() as u16;
    vertices.push(BuiltinMeshVertex {
        pos: a,
        normal,
        uv: auv,
    });
    vertices.push(BuiltinMeshVertex {
        pos: bv,
        normal,
        uv: buv,
    });
    vertices.push(BuiltinMeshVertex {
        pos: cv,
        normal,
        uv: cuv,
    });
    indices.extend_from_slice(&[base, base + 1, base + 2]);
}

fn push_quad(
    vertices: &mut Vec<BuiltinMeshVertex>,