//! This example demonstrates how to generate a mesh. #![allow(clippy::bool_assert_comparison, clippy::useless_conversion)] use glam::{Vec2, Vec3}; type Face = [u32; 3]; #[derive(Debug)] struct Vertex { position: Vec3, normal: Vec3, tex_coord: Vec2, } struct Mesh { faces: Vec<Face>, vertices: Vec<Vertex>, } fn vertex(mesh: &Mesh, face: usize, vert: usize) -> &Vertex { let vs: &[u32; 3] = &mesh.faces[face]; &mesh.vertices[vs[vert] as usize] } impl bevy_mikktspace::Geometry for Mesh { fn num_faces(&self) -> usize { self.faces.len() } fn num_vertices_of_face(&self, _face: usize) -> usize { 3 } fn position(&self, face: usize, vert: usize) -> [f32; 3] { vertex(self, face, vert).position.into() } fn normal(&self, face: usize, vert: usize) -> [f32; 3] { vertex(self, face, vert).normal.into() } fn tex_coord(&self, face: usize, vert: usize) -> [f32; 2] { vertex(self, face, vert).tex_coord.into() } fn set_tangent_encoded(&mut self, tangent: [f32; 4], face: usize, vert: usize) { println!( "{face}-{vert}: v: {v:?}, vn: {vn:?}, vt: {vt:?}, vx: {vx:?}", face = face, vert = vert, v = vertex(self, face, vert).position, vn = vertex(self, face, vert).normal, vt = vertex(self, face, vert).tex_coord, vx = tangent, ); } } fn make_cube() -> Mesh { struct ControlPoint { uv: [f32; 2], dir: [f32; 3], } let mut faces = Vec::new(); let mut ctl_pts = Vec::new(); let mut vertices = Vec::new(); // +x plane { let base = ctl_pts.len() as u32; faces.push([base, base + 1, base + 4]); faces.push([base + 1, base + 2, base + 4]); faces.push([base + 2, base + 3, base + 4]); faces.push([base + 3, base, base + 4]); ctl_pts.push(ControlPoint { uv: [0.0, 0.0], dir: [1.0, -1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 1.0], dir: [1.0, -1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [1.0, 1.0], dir: [1.0, 1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [1.0, 0.0], dir: [1.0, 1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [0.5, 0.5], dir: [1.0, 0.0, 0.0], }); } // -x plane { let base = ctl_pts.len() as u32; faces.push([base, base + 1, base + 4]); faces.push([base + 1, base + 2, base + 4]); faces.push([base + 2, base + 3, base + 4]); faces.push([base + 3, base, base + 4]); ctl_pts.push(ControlPoint { uv: [1.0, 0.0], dir: [-1.0, 1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [1.0, 1.0], dir: [-1.0, 1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 1.0], dir: [-1.0, -1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 0.0], dir: [-1.0, -1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [0.5, 0.5], dir: [-1.0, 0.0, 0.0], }); } // +y plane { let base = ctl_pts.len() as u32; faces.push([base, base + 1, base + 4]); faces.push([base + 1, base + 2, base + 4]); faces.push([base + 2, base + 3, base + 4]); faces.push([base + 3, base, base + 4]); ctl_pts.push(ControlPoint { uv: [0.0, 0.0], dir: [1.0, 1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 1.0], dir: [1.0, 1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 1.0], dir: [-1.0, 1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 0.0], dir: [-1.0, 1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 0.5], dir: [0.0, 1.0, 0.0], }); } // -y plane { let base = ctl_pts.len() as u32; faces.push([base, base + 1, base + 4]); faces.push([base + 1, base + 2, base + 4]); faces.push([base + 2, base + 3, base + 4]); faces.push([base + 3, base, base + 4]); ctl_pts.push(ControlPoint { uv: [0.0, 0.0], dir: [-1.0, -1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 1.0], dir: [-1.0, -1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 1.0], dir: [1.0, -1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 0.0], dir: [1.0, -1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 0.5], dir: [0.0, -1.0, 0.0], }); } // +z plane { let base = ctl_pts.len() as u32; faces.push([base, base + 1, base + 4]); faces.push([base + 1, base + 2, base + 4]); faces.push([base + 2, base + 3, base + 4]); faces.push([base + 3, base, base + 4]); ctl_pts.push(ControlPoint { uv: [0.0, 0.0], dir: [-1.0, 1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 1.0], dir: [-1.0, -1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [1.0, 1.0], dir: [1.0, -1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [1.0, 0.0], dir: [1.0, 1.0, 1.0], }); ctl_pts.push(ControlPoint { uv: [0.5, 0.5], dir: [0.0, 0.0, 1.0], }); } // -z plane { let base = ctl_pts.len() as u32; faces.push([base, base + 1, base + 4]); faces.push([base + 1, base + 2, base + 4]); faces.push([base + 2, base + 3, base + 4]); faces.push([base + 3, base, base + 4]); ctl_pts.push(ControlPoint { uv: [1.0, 0.0], dir: [1.0, 1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [1.0, 1.0], dir: [1.0, -1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 1.0], dir: [-1.0, -1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [0.0, 0.0], dir: [-1.0, 1.0, -1.0], }); ctl_pts.push(ControlPoint { uv: [0.5, 0.5], dir: [0.0, 0.0, -1.0], }); } for pt in ctl_pts { let p: Vec3 = pt.dir.into(); let n: Vec3 = p.normalize(); let t: Vec2 = pt.uv.into(); vertices.push(Vertex { position: (p / 2.0).into(), normal: n.into(), tex_coord: t.into(), }); } Mesh { faces, vertices } } fn main() { let mut cube = make_cube(); let ret = bevy_mikktspace::generate_tangents(&mut cube); assert_eq!(true, ret); }