64 lines
2.0 KiB
Rust
64 lines
2.0 KiB
Rust
use crate::types_defined::{Ray, Vec3};
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pub fn clamp(value: f32, low: f32, high: f32) -> f32 {
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if value < low {
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return low;
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}
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if value > high {
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return high;
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}
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return value;
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}
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pub fn near_zero(v: Vec3) -> bool {
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const EPSILON: f32 = 1e-4;
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v.x.abs() < EPSILON && v.y.abs() < EPSILON && v.z.abs() < EPSILON
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}
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pub fn reflect(v: Vec3, n: Vec3) -> Vec3 {
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v - ((2.0 * v.dot(n)) * n)
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}
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// v, normal, 折射率
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pub fn refract(uv: Vec3, n: Vec3, etai_over_etat: f32) -> Vec3 {
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// auto cos_theta = std::fmin(dot(-uv, n), 1.0);
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// vec3 r_out_perp = etai_over_etat * (uv + cos_theta*n);
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// vec3 r_out_parallel = -std::sqrt(std::fabs(1.0 - r_out_perp.length_squared())) * n;
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// return r_out_perp + r_out_parallel;
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let cos_theta = (-uv.dot(n)).min(1.0);
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let r_out_perp = etai_over_etat * (uv + cos_theta * n);
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let r_out_parallel = -(f32::sqrt(f32::abs(1.0 - r_out_perp.length()))) * n;
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r_out_perp + r_out_parallel
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// let v_normalized = v;
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// let n_normalized = n.normalize();
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// let cos_theta = f32::min(-v_normalized.dot(n_normalized), 1.0);
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// let sin_theta = (1.0 - cos_theta * cos_theta).sqrt();
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// // 检查是否全内反射（无法折射）
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// if etai_over_etat * sin_theta > 1.0 {
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// return reflect(v_normalized, n)
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// }
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// let r_out_perp = etai_over_etat * (v_normalized + cos_theta * n_normalized);
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// let discriminant = 1.0 - r_out_perp.length_squared();
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// // if discriminant < 0.0 {
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// // return -1.0 * v; // 全内反射，返回零向量（或改为反射）
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// // }
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// let r_out_parallel = -discriminant * n_normalized;
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// r_out_perp + r_out_parallel
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}
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pub fn is_front_face(r: &Ray, outward_normal: Vec3) -> bool {
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r.direction.dot(outward_normal) < 0.0
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}
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pub fn front_face_normal(r: &Ray, outward_normal: Vec3) -> Vec3 {
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if is_front_face(r, outward_normal) {
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outward_normal
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} else {
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-1. * outward_normal
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}
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} |