From afc497002353c9069df30c2e6f0700515305e8a8 Mon Sep 17 00:00:00 2001
From: numzero <numzer0@yandex.ru>
Date: Sat, 27 Apr 2024 19:28:01 +0300
Subject: [PATCH] Extract rendering into a function

---
 src/main.rs | 55 ++++++++++++++++++++++++++++-------------------------
 1 file changed, 29 insertions(+), 26 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index d745198..d267182 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -9,7 +9,7 @@ use std::io::Write;
 use rand::Rng;
 use glm::*;
 use show_image::{ImageInfo, ImageView, WindowOptions};
-use crate::mesh_loader::load_mesh;
+use crate::mesh_loader::{Face, load_mesh};
 
 const W: i32 = 320;
 const H: i32 = 240;
@@ -57,41 +57,20 @@ fn ypr_to_mat(ypr: Vec3) -> Mat3 {
 	m_roll * m_pitch * m_yaw
 }
 
-#[show_image::main]
-fn main() -> Result<(), Box<dyn Error>> {
-	let args: Vec<String> = env::args().collect();
-	let mesh = {
-		let f = File::open(&args[1])?;
-		let mut f = BufReader::new(f);
-		load_mesh(&mut f)?
-	};
+fn render(mesh: &[Face], camera: impl Fn(Vec2) -> (Vec3, Vec3)) -> Image {
 	let mut img = Image {
 		w: W,
 		h: H,
 		data: vec![0; (3 * W * H) as usize],
 	};
-	let m_view = ypr_to_mat(vec3(135.0 * PI / 180.0, -30.0 * PI / 180.0, 0.0f32));
-	let m_camera = transpose(&m_view);
 	let img_size = vec2(W as f32, H as f32);
 	for y in 0..H {
 		for x in 0..W {
-			let img_coords: Vec2 = vec2(x as f32, y as f32);
-
-			// perspective projection
+			let img_coords = vec2(x as f32, y as f32);
 			let off = (img_coords - img_size * 0.5) / img_size.y;
-			let base = vec3(0.0, 0.0, -40.0);
-			let ray = vec3(off.x, off.y, 2.0);
-
-			// orthographic projection
-			// let off = (img_coords - img_size * 0.5) / SCALE;
-			// let base = vec3(off.x, off.y, -10.0);
-			// let ray = vec3(0.0, 0.0, 1.0);
-
-			let base = m_camera * base;
-			let ray = m_camera * normalize(ray);
+			let (base, ray) = camera(off);
 			let mut dist = f32::INFINITY;
-
-			for f in &mesh {
+			for f in mesh {
 				let color = clamp(to_ivec3(f.normal * 120.0 + 128.0), ivec3(0, 0, 0), ivec3(255, 255, 255));
 				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) {
@@ -110,6 +89,30 @@ fn main() -> Result<(), Box<dyn Error>> {
 			}
 		}
 	}
+	img
+}
+
+#[show_image::main]
+fn main() -> Result<(), Box<dyn Error>> {
+	let args: Vec<String> = env::args().collect();
+	let mesh = {
+		let f = File::open(&args[1])?;
+		let mut f = BufReader::new(f);
+		load_mesh(&mut f)?
+	};
+	let m_view = ypr_to_mat(vec3(135.0 * PI / 180.0, -30.0 * PI / 180.0, 0.0f32));
+	let m_camera = transpose(&m_view);
+	let img = render(mesh.as_slice(), |off| {
+		// perspective projection
+		let base = vec3(0.0, 0.0, -40.0);
+		let ray = vec3(off.x, off.y, 2.0);
+
+		// orthographic projection
+		// let base = vec3(off.x, off.y, -10.0);
+		// let ray = vec3(0.0, 0.0, 1.0);
+
+		(m_camera * base, m_camera * ray)
+	});
 
 	let window = show_image::create_window("Raytracing", WindowOptions::default())?;
 	let image = ImageView::new(ImageInfo::rgb8(W as u32, H as u32), img.data());