cedd0c5028
# Objective - Contributes to #15460 - Allows `bevy_mikktspace` to be used in `no_std` contexts. ## Solution - Added `std` (default) and `libm` features which control the inclusion of the standard library. To use `bevy_mikktspace` in `no_std` environments, enable the `libm` feature. ## Testing - CI - `cargo clippy -p bevy_mikktspace --target "x86_64-unknown-none" --no-default-features --features libm`
102 lines
3.2 KiB
Rust
102 lines
3.2 KiB
Rust
#![allow(
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unsafe_op_in_unsafe_fn,
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clippy::all,
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clippy::undocumented_unsafe_blocks,
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clippy::ptr_cast_constness,
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// FIXME(15321): solve CI failures, then replace with `#![expect()]`.
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missing_docs
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)]
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#![cfg_attr(docsrs, feature(doc_auto_cfg))]
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#![doc(
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html_logo_url = "https://bevyengine.org/assets/icon.png",
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html_favicon_url = "https://bevyengine.org/assets/icon.png"
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)]
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#![cfg_attr(not(feature = "std"), no_std)]
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extern crate alloc;
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use glam::{Vec2, Vec3};
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mod generated;
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/// The interface by which mikktspace interacts with your geometry.
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pub trait Geometry {
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/// Returns the number of faces.
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fn num_faces(&self) -> usize;
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/// Returns the number of vertices of a face.
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fn num_vertices_of_face(&self, face: usize) -> usize;
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/// Returns the position of a vertex.
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fn position(&self, face: usize, vert: usize) -> [f32; 3];
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/// Returns the normal of a vertex.
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fn normal(&self, face: usize, vert: usize) -> [f32; 3];
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/// Returns the texture coordinate of a vertex.
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fn tex_coord(&self, face: usize, vert: usize) -> [f32; 2];
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/// Sets the generated tangent for a vertex.
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/// Leave this function unimplemented if you are implementing
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/// `set_tangent_encoded`.
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fn set_tangent(
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&mut self,
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tangent: [f32; 3],
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_bi_tangent: [f32; 3],
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_f_mag_s: f32,
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_f_mag_t: f32,
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bi_tangent_preserves_orientation: bool,
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face: usize,
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vert: usize,
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) {
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let sign = if bi_tangent_preserves_orientation {
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1.0
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} else {
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-1.0
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};
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self.set_tangent_encoded([tangent[0], tangent[1], tangent[2], sign], face, vert);
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}
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/// Sets the generated tangent for a vertex with its bi-tangent encoded as the 'W' (4th)
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/// component in the tangent. The 'W' component marks if the bi-tangent is flipped. This
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/// is called by the default implementation of `set_tangent`; therefore, this function will
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/// not be called by the crate unless `set_tangent` is unimplemented.
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fn set_tangent_encoded(&mut self, _tangent: [f32; 4], _face: usize, _vert: usize) {}
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}
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/// Generates tangents for the input geometry.
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///
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/// # Errors
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///
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/// Returns `false` if the geometry is unsuitable for tangent generation including,
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/// but not limited to, lack of vertices.
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#[allow(unsafe_code)]
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pub fn generate_tangents<I: Geometry>(geometry: &mut I) -> bool {
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unsafe { generated::genTangSpace(geometry, 180.0) }
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}
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fn get_position<I: Geometry>(geometry: &mut I, index: usize) -> Vec3 {
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let (face, vert) = index_to_face_vert(index);
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geometry.position(face, vert).into()
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}
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fn get_tex_coord<I: Geometry>(geometry: &mut I, index: usize) -> Vec3 {
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let (face, vert) = index_to_face_vert(index);
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let tex_coord: Vec2 = geometry.tex_coord(face, vert).into();
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let val = tex_coord.extend(1.0);
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val
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}
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fn get_normal<I: Geometry>(geometry: &mut I, index: usize) -> Vec3 {
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let (face, vert) = index_to_face_vert(index);
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geometry.normal(face, vert).into()
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}
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fn index_to_face_vert(index: usize) -> (usize, usize) {
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(index >> 2, index & 0x3)
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}
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fn face_vert_to_index(face: usize, vert: usize) -> usize {
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face << 2 | vert & 0x3
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}
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