49 lines
1.2 KiB
Rust
49 lines
1.2 KiB
Rust
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use cgmath::{InnerSpace, Vector3};
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use super::ray::Ray;
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pub struct Triangle {
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pub points: [Vector3<f32>; 3],
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}
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impl Triangle {
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pub fn new(v0: Vector3<f32>, v1: Vector3<f32>, v2: Vector3<f32>) -> Triangle {
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Triangle {
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points: [v0, v1, v2],
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}
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}
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// source: https://www.scratchapixel.com/lessons/3d-basic-rendering/ray-tracing-rendering-a-triangle/moller-trumbore-ray-triangle-intersection
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pub fn intersect_mt(&self, ray: &Ray, t: &mut f32) -> bool {
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let v0v1 = self.points[1] - self.points[0];
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let v0v2 = self.points[2] - self.points[0];
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let pvec = ray.direction.cross(v0v2);
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let det = v0v1.dot(pvec);
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// ray and triangle are parallel if det is close to 0
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if det.abs() < 0.001 {
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return false;
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}
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let inv_det = 1.0 / det;
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let tvec = ray.origin - self.points[0];
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let u = tvec.dot(pvec) * inv_det;
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if u < 0.0 || u > 1.0 {
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return false;
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}
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let qvec = tvec.cross(v0v1);
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let v = ray.direction.dot(qvec) * inv_det;
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if v < 0.0 || u + v > 1.0 {
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return false;
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}
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*t = v0v2.dot(qvec) * inv_det;
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true
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}
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}
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