Texture?

models/spacecraft2.obj

@@ -1,6 +1,5 @@
 # Blender 3.6.5
 # www.blender.org
-mtllib spacecraft2.mtl
 o Cube
 v -1.000000 0.000000 3.000000
 v -2.000000 0.000000 2.000000
@@ -60,50 +59,68 @@ vn 0.3487 -0.9300 -0.1162
 vn -0.4444 -0.8889 -0.1111
 vn -0.3015 -0.9045 0.3015
 vn 0.2182 -0.4364 0.8729
-vt 0.000000 0.000000
+vt 0.342147 0.420195
+vt 0.509380 0.482116
+vt 0.342147 0.586861
+vt 0.513220 0.668431
+vt 0.680454 0.813685
+vt 0.000000 0.840390
+vt 0.684294 1.000000
+vt 0.855367 0.914903
+vt 0.855367 0.748236
+vt 0.684294 0.666667
+vt 0.594917 0.481234
+vt 0.680454 0.147018
+vt 0.769831 0.415785
+vt 0.769830 0.582451
+vt 0.513220 0.335097
+vt 0.000000 0.173723
+vt 0.684294 0.000000
+vt 0.855367 0.248236
+vt 0.855367 0.081569
+vt 0.684294 0.333333
 s 0
-usemtl Material
+f 8/1/1 18/2/1 16/3/1
-f 8/1/1 18/1/1 16/1/1
+f 16/3/2 18/2/2 15/4/2
-f 16/1/2 18/1/2 15/1/2
+f 18/2/3 19/5/3 15/4/3
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-f 20/1/9 18/1/9 17/1/9
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-f 1/1/7 9/1/7 20/1/7
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src/bin/textured/main.rs

@@ -0,0 +1,153 @@
+use glam::*;
+use refraction::mesh_loader::load_mesh;
+use refraction::mesh_tracer::{trace_to_mesh, Mesh};
+use show_image::event::{ElementState, VirtualKeyCode, WindowEvent};
+use show_image::{exit, ImageInfo, ImageView, WindowOptions};
+use std::env;
+use std::error::Error;
+use std::f32::consts::PI;
+use std::fs::File;
+use std::io::BufReader;
+use std::sync::atomic::{AtomicUsize, Ordering::Relaxed};
+
+const W: i32 = 320;
+const H: i32 = 240;
+
+#[derive(Copy, Clone)]
+struct Color(u8, u8, u8);
+
+struct Image {
+	w: i32,
+	h: i32,
+	data: Vec<u8>,
+}
+
+impl Image {
+	fn data(&self) -> &[u8] {
+		self.data.as_slice()
+	}
+
+	fn put_pixel(&mut self, x: i32, y: i32, color: Color) {
+		if x < 0 || x >= self.w || y < 0 || y > self.h {
+			return;
+		}
+		let index = 3 * (x + self.w * y) as usize;
+		self.data[index] = color.0;
+		self.data[index + 1] = color.1;
+		self.data[index + 2] = color.2;
+	}
+}
+
+fn ypr_to_mat(ypr: Vec3) -> Mat3 {
+	let Vec3 {
+		x: yaw,
+		y: pitch,
+		z: roll,
+	} = ypr;
+	let m_roll = mat3(
+		vec3(roll.cos(), roll.sin(), 0.0),
+		vec3(-roll.sin(), roll.cos(), 0.0),
+		vec3(0.0, 0.0, 1.0),
+	);
+	let m_yaw = mat3(
+		vec3(yaw.cos(), 0.0, yaw.sin()),
+		vec3(0.0, 1.0, 0.0),
+		vec3(-yaw.sin(), 0.0, yaw.cos()),
+	);
+	let m_pitch = mat3(
+		vec3(1.0, 0.0, 0.0),
+		vec3(0.0, pitch.cos(), -pitch.sin()),
+		vec3(0.0, pitch.sin(), pitch.cos()),
+	);
+	m_roll * m_pitch * m_yaw
+}
+
+fn render(mesh: &Mesh, camera: impl Fn(Vec2) -> (Vec3, Vec3)) -> Image {
+	let bkg = vec3(0.0, 0.0, 0.0);
+	let mut img = Image {
+		w: W,
+		h: H,
+		data: vec![0; (3 * W * H) as usize],
+	};
+	let img_size = vec2(W as f32, H as f32);
+	for y in 0..H {
+		for x in 0..W {
+			let img_coords = vec2(x as f32, y as f32);
+			let off = (img_coords - img_size * 0.5) / img_size.y;
+			let (base, ray) = camera(off);
+			let color = if let Some(r) = trace_to_mesh(mesh, base, ray.normalize()) {
+				// to_vec3(0.45) * dot(r.normal, normalize(vec3(-1.0, 1.0, -1.0))) + 0.50
+				vec3(r.tex_coords.x, r.tex_coords.y, 0.)
+			} else {
+				bkg
+			};
+			let color = (color * 255.0).as_ivec3().clamp(IVec3::splat(0), IVec3::splat(255));
+			img.put_pixel(x, y, Color(color.x as u8, color.y as u8, color.z as u8));
+		}
+	}
+	img
+}
+
+fn persp(dist: f32, off: Vec2) -> (Vec3, Vec3) {
+	(vec3(0., 0., -dist), vec3(off.x, off.y, dist))
+}
+
+fn ortho(dist: f32, off: Vec2) -> (Vec3, Vec3) {
+	(vec3(off.x, off.y, -dist), vec3(0., 0., 1.))
+}
+
+#[test]
+fn test_projs() {
+	fn check(f: fn(dist: f32, off: Vec2) -> (Vec3, Vec3), x: f32, y: f32, z: f32) {
+		let (base, ray) = f(z, vec2(x, y));
+		let at_dist = base + ray * (z / ray.z);
+		assert_eq!(at_dist, vec3(x, y, 0.));
+	}
+	check(persp, 1., 2., 3.);
+	check(ortho, 1., 2., 3.);
+	check(persp, 5., 3., 7.);
+	check(ortho, 9., 1., 8.);
+}
+
+// add_event_handler wants 'static + Send. Let it be so.
+static PROJ_INDEX: AtomicUsize = AtomicUsize::new(0);
+static PROJS: [fn(dist: f32, off: Vec2) -> (Vec3, Vec3); 2] = [persp, ortho];
+
+#[show_image::main]
+fn main() -> Result<(), Box<dyn Error>> {
+	let args: Vec<String> = env::args().collect();
+	if args.len() != 2 {
+		println!("Usage: {} path/to/model.obj", args[0]);
+		exit(1);
+	}
+	let mesh = {
+		let f = File::open(&args[1])?;
+		let mut f = BufReader::new(f);
+		load_mesh(&mut f)?
+	};
+	let window = show_image::create_window("Raytracing", WindowOptions::default())?;
+	window.add_event_handler(|_wnd, ev, _ctl| {
+		if let WindowEvent::KeyboardInput(ev) = ev {
+			if ev.input.state != ElementState::Pressed {
+				return;
+			}
+			if let Some(VirtualKeyCode::Tab) = ev.input.key_code {
+				PROJ_INDEX.store((PROJ_INDEX.load(Relaxed) + 1) % PROJS.len(), Relaxed);
+			}
+		}
+	})?;
+	loop {
+		for phi in 0..360 {
+			let proj = PROJS[PROJ_INDEX.load(Relaxed)];
+			let m_view = ypr_to_mat(vec3((135.0 + phi as f32) * PI / 180.0, -30.0 * PI / 180.0, 0.0f32));
+			let m_camera = m_view.transpose();
+			let img = render(mesh.as_slice(), |off| {
+				let (base, ray) = proj(40., 20. * off);
+				(m_camera * base, m_camera * ray)
+			});
+
+			let image = ImageView::new(ImageInfo::rgb8(W as u32, H as u32), img.data());
+			window.set_image("image", image)?;
+		}
+	}
+}

src/mesh_loader.rs

@@ -5,7 +5,7 @@ use std::io;
 struct ObjVertex {
 	vertex: usize,
 	normal: usize,
-	// tex_coord: usize,
+	tex_coord: usize,
 }
 
 #[derive(Copy, Clone, Debug)]
@@ -39,7 +39,7 @@ impl ObjMesh {
 		assert_eq!(tokens.len(), 3);
 		ObjVertex {
 			vertex: tokens[0],
-			// tex_coord: tokens[1],
+			tex_coord: tokens[1],
 			normal: tokens[2],
 		}
 	}
@@ -80,6 +80,7 @@ impl ObjMesh {
 			.iter()
 			.map(|face| Face {
 				vertices: face.vertices.map(|iv| self.vertices[iv.vertex]),
+				tex_coords: face.vertices.map(|iv| self.tex_coords[iv.tex_coord]),
 				normal: self.normals[face.vertices[0].normal],
 			})
 			.collect()
@@ -89,6 +90,7 @@ impl ObjMesh {
 #[derive(Copy, Clone, Debug)]
 pub struct Face {
 	pub vertices: [Vec3; 3],
+	pub tex_coords: [Vec2; 3],
 	pub normal: Vec3,
 }
 

src/mesh_tracer.rs

@@ -1,10 +1,11 @@
 use crate::mesh_loader::Face;
-use glam::{mat3, Vec3};
+use glam::{mat3, vec3, Vec2, Vec3};
 
 pub type Mesh = [Face];
 
 pub struct TraceResult {
 	pub distance: f32,
+	pub tex_coords: Vec2,
 	pub normal: Vec3,
 }
 
@@ -17,8 +18,10 @@ pub fn trace_to_mesh_all(mesh: &Mesh, base: Vec3, ray: Vec3) -> impl Iterator<It
 		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]);
+		let w = vec3(1. - rel.x - rel.y, rel.x, rel.y);
 		Some(TraceResult {
 			distance: rel.z,
+			tex_coords: w.x * f.tex_coords[0] + w.y * f.tex_coords[1] + w.z * f.tex_coords[2],
 			normal: f.normal,
 		})
 	})