From fca01e05f4dd056cff0b47d4ebf5edfd94605dde Mon Sep 17 00:00:00 2001
From: numzero <numzer0@yandex.ru>
Date: Sat, 14 Sep 2024 15:14:15 +0300
Subject: [PATCH] Extract mesh tracing into the lib crate

---
 src/bin/mesh/main.rs | 46 ++------------------------------------------
 src/lib.rs           |  1 +
 src/mesh_tracer.rs   | 40 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 44 deletions(-)

diff --git a/src/bin/mesh/main.rs b/src/bin/mesh/main.rs
index 37a8e45..50d78e8 100644
--- a/src/bin/mesh/main.rs
+++ b/src/bin/mesh/main.rs
@@ -1,5 +1,6 @@
 use glam::*;
-use refraction::mesh_loader::{load_mesh, Face};
+use refraction::mesh_loader::load_mesh;
+use refraction::mesh_tracer::{trace_to_mesh, Mesh};
 use show_image::{ImageInfo, ImageView, WindowOptions};
 use std::env;
 use std::error::Error;
@@ -59,44 +60,6 @@ fn ypr_to_mat(ypr: Vec3) -> Mat3 {
 	m_roll * m_pitch * m_yaw
 }
 
-type Mesh = [Face];
-
-struct TraceResult {
-	distance: f32,
-	normal: Vec3,
-}
-
-fn trace_to_mesh(mesh: &Mesh, base: Vec3, ray: Vec3) -> Option<TraceResult> {
-	let mut ret: Option<TraceResult> = None;
-	let mut dist = f32::INFINITY;
-	for f in mesh {
-		let fs = (0..3).map(|k| edge_dist(f.vertices[k], f.vertices[(k + 1) % 3], base, ray));
-		if fs.into_iter().all(|f| f >= 0.0) {
-			let m = mat3(
-				f.vertices[1] - f.vertices[0],
-				f.vertices[2] - f.vertices[0],
-				-ray,
-			);
-			let m = m.inverse();
-			let rel = m * (base - f.vertices[0]);
-			if rel.z > dist {
-				continue;
-			}
-			dist = rel.z;
-			ret = Some(TraceResult {
-				distance: rel.z,
-				normal: f.normal,
-			});
-		}
-	}
-	ret
-}
-
-struct Location {
-	pos: Vec3,
-	rot: Vec4,
-}
-
 fn render(mesh: &Mesh, camera: impl Fn(Vec2) -> (Vec3, Vec3)) -> Image {
 	let bkg = vec3(0.0, 0.0, 0.0);
 	let mut img = Image {
@@ -159,8 +122,3 @@ fn main() -> Result<(), Box<dyn Error>> {
 		}
 	}
 }
-
-fn edge_dist(a: Vec3, b: Vec3, base: Vec3, dir: Vec3) -> f32 {
-	// Note: given that the input is not arbitrary but comes from a cartesian product of certain (a, b) pairs and certain (base, dir) pairs, this can be optimized from Cnm to an+bm+cnm with c<C.
-	mat3(b - a, base - a, -dir).determinant()
-}
diff --git a/src/lib.rs b/src/lib.rs
index 9cbfea6..f8a2b53 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1 +1,2 @@
 pub mod mesh_loader;
+pub mod mesh_tracer;
diff --git a/src/mesh_tracer.rs b/src/mesh_tracer.rs
index e69de29..1053e41 100644
--- a/src/mesh_tracer.rs
+++ b/src/mesh_tracer.rs
@@ -0,0 +1,40 @@
+use crate::mesh_loader::Face;
+use glam::{mat3, Vec3};
+
+pub type Mesh = [Face];
+
+pub struct TraceResult {
+	pub distance: f32,
+	pub normal: Vec3,
+}
+
+pub fn trace_to_mesh(mesh: &Mesh, base: Vec3, ray: Vec3) -> Option<TraceResult> {
+	let mut ret: Option<TraceResult> = None;
+	let mut dist = f32::INFINITY;
+	for f in mesh {
+		let fs = (0..3).map(|k| edge_dist(f.vertices[k], f.vertices[(k + 1) % 3], base, ray));
+		if fs.into_iter().all(|f| f >= 0.0) {
+			let m = mat3(
+				f.vertices[1] - f.vertices[0],
+				f.vertices[2] - f.vertices[0],
+				-ray,
+			);
+			let m = m.inverse();
+			let rel = m * (base - f.vertices[0]);
+			if rel.z > dist {
+				continue;
+			}
+			dist = rel.z;
+			ret = Some(TraceResult {
+				distance: rel.z,
+				normal: f.normal,
+			});
+		}
+	}
+	ret
+}
+
+fn edge_dist(a: Vec3, b: Vec3, base: Vec3, dir: Vec3) -> f32 {
+	// Note: given that the input is not arbitrary but comes from a cartesian product of certain (a, b) pairs and certain (base, dir) pairs, this can be optimized from Cnm to an+bm+cnm with c<C.
+	mat3(b - a, base - a, -dir).determinant()
+}