bevy/src/lib.rs
2019-05-12 20:53:14 +02:00

74 lines
2.4 KiB
Rust

mod generated;
use nalgebra::{Point2, Point3, Vector3, Vector4};
/// The interface by which mikktspace interacts with your geometry.
pub trait Geometry {
/// Returns the number of faces.
fn num_faces(&self) -> usize;
/// Returns the number of vertices of a face.
fn num_vertices_of_face(&self, face: usize) -> usize;
/// Returns the position of a vertex.
fn position(&self, face: usize, vert: usize) -> Point3<f32>;
/// Returns the normal of a vertex.
fn normal(&self, face: usize, vert: usize) -> Vector3<f32>;
/// Returns the texture coordinate of a vertex.
fn tex_coord(&self, face: usize, vert: usize) -> Point2<f32>;
/// Sets a vertex' generated tangent.
fn set_tangent(
&mut self,
tangent: Vector3<f32>,
_bi_tangent: Vector3<f32>,
_f_mag_s: f32,
_f_mag_t: f32,
bi_tangent_preserves_orientation: bool,
face: usize,
vert: usize,
) {
let sign = if bi_tangent_preserves_orientation {
1.0
} else {
-1.0
};
self.set_tangent_encoded(tangent.insert_row(3, sign), face, vert);
}
/// Sets a vertex' generated tangent with the bi-tangent encoded as the W component in the
/// tangent. The W component marks if the bi-tangent is flipped. This will only be called if
/// `set_tangent` is not implemented.
fn set_tangent_encoded(&mut self, _tangent: Vector4<f32>, _face: usize, _vert: usize) {}
}
/// Default (recommended) Angular Threshold is 180 degrees, which means threshold disabled.
pub fn generate_tangents_default<I: Geometry>(geometry: &mut I) -> bool {
unsafe { generated::genTangSpace(geometry, 180.0) }
}
fn get_position<I: Geometry>(geometry: &mut I, index: usize) -> Vector3<f32> {
let (face, vert) = index_to_face_vert(index);
geometry.position(face, vert).coords
}
fn get_tex_coord<I: Geometry>(geometry: &mut I, index: usize) -> Vector3<f32> {
let (face, vert) = index_to_face_vert(index);
geometry.tex_coord(face, vert).coords.insert_row(2, 1.0)
}
fn get_normal<I: Geometry>(geometry: &mut I, index: usize) -> Vector3<f32> {
let (face, vert) = index_to_face_vert(index);
geometry.normal(face, vert)
}
fn index_to_face_vert(index: usize) -> (usize, usize) {
(index >> 2, index & 0x3)
}
fn face_vert_to_index(face: usize, vert: usize) -> usize {
face << 2 | vert & 0x3
}