From db48a786ac8c033c6d6d4b4f9cf65dac03ecefa8 Mon Sep 17 00:00:00 2001
From: numzero <numzer0@yandex.ru>
Date: Mon, 30 Dec 2024 03:02:04 +0300
Subject: [PATCH] Move camera!

---
 src/bin/minitracer/main.rs | 29 ++++++++++++++++++++---------
 1 file changed, 20 insertions(+), 9 deletions(-)

diff --git a/src/bin/minitracer/main.rs b/src/bin/minitracer/main.rs
index 8bc2d86..9ae0074 100644
--- a/src/bin/minitracer/main.rs
+++ b/src/bin/minitracer/main.rs
@@ -1,6 +1,6 @@
 use std::error::Error;
 
-use glam::{uvec2, vec2, vec3};
+use glam::{mat3, uvec2, vec2, vec3, Vec3};
 use image::ImageReader;
 use present::Presenter;
 use trace::{Tracer, TracerData, TracerEnv, Vertex};
@@ -16,17 +16,22 @@ mod trace;
 
 pub use trace::Sphere;
 
-fn make_viewport(w: u32, h: u32) -> [Vertex; 4] {
+fn make_viewport(eye: Vec3, w: u32, h: u32) -> [Vertex; 4] {
 	let size = uvec2(w, h).as_vec2();
 	let size = size.normalize();
-	let (w, h) = (size.x, size.y);
-	let r = 1.0f32;
+	let (w, h, d) = (size.x, size.y, 1.);
 	let screen_coord = [vec2(-1., -1.), vec2(1., -1.), vec2(-1., 1.), vec2(1., 1.)];
-	let eye = vec3(-r, 0., 0.);
-	let world_coord = [vec3(0., -w, -h), vec3(0., w, -h), vec3(0., -w, h), vec3(0., w, h)];
+
+	let up = Vec3::Z;
+	let fwd = -eye.normalize();
+	let right = eye.cross(up).normalize();
+	let up = eye.cross(right).normalize();
+	let m = mat3(fwd, right, up);
+
+	let world_coord = [vec3(d, -w, -h), vec3(d, w, -h), vec3(d, -w, h), vec3(d, w, h)];
 	[0, 1, 2, 3].map(|k| Vertex {
 		eye,
-		world: world_coord[k],
+		world: eye + m * (world_coord[k]),
 		screen: screen_coord[k],
 	})
 }
@@ -49,11 +54,16 @@ fn main() {
 	let output_format = wgpu::TextureFormat::Bgra8UnormSrgb;
 	let hdr_format = wgpu::TextureFormat::Rgba16Float;
 	let mut tracer = Tracer::new(&device, hdr_format);
+	let mut rng = rand_pcg::Pcg32::new(42, 0);
 	let sphere_params: Vec<_> = {
-		let mut rng = rand_pcg::Pcg32::new(42, 0);
 		let distr = anim::distr();
 		(0..N_SPHERES).map(|_| distr(&mut rng)).collect()
 	};
+	let camera_params = {
+		let mut p = anim::distr()(&mut rng);
+		p.frequencies *= 0.1;
+		p
+	};
 	let tracer_env = TracerEnv::new(&device, &tracer, &envmap);
 
 	let presenter = Presenter::new(&device, output_format);
@@ -80,7 +90,6 @@ fn main() {
 							desired_maximum_frame_latency: 2,
 						},
 					);
-					tracer.set_view(&queue, &make_viewport(physical_size.width, physical_size.height));
 					surface_configured = true;
 				}
 				WindowEvent::RedrawRequested => {
@@ -122,6 +131,8 @@ fn main() {
 						for _ in 0..RAYS_PER_PIXEL {
 							frame += 1;
 							let time = frame as f32 / (60. * RAYS_PER_PIXEL as f32);
+							let camera_pos = camera_params.to_sphere(time).center;
+							tracer.set_view(&queue, &make_viewport(camera_pos, size.width, size.height));
 							let spheres: Vec<_> = sphere_params.iter().map(|p| p.to_sphere(time)).collect();
 							let data = TracerData::new(&device, &tracer, &spheres);
 							tracer.render(