From a0bfa246ec15d9a132e13945314afed4b7eef309 Mon Sep 17 00:00:00 2001
From: numzero <numzer0@yandex.ru>
Date: Sun, 22 Sep 2024 23:54:35 +0300
Subject: [PATCH] Change the coordinate system

---
 src/bin/wireframe/main.rs | 35 ++++++++++++++++++++++++-----------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/src/bin/wireframe/main.rs b/src/bin/wireframe/main.rs
index 526aea2..5c74778 100644
--- a/src/bin/wireframe/main.rs
+++ b/src/bin/wireframe/main.rs
@@ -18,6 +18,11 @@ use winit::{
 
 mod scene;
 
+// The coordinate system:
+// * X: forward
+// * Y: left
+// * Z: up
+
 #[derive(Copy, Clone)]
 struct Vertex {
 	position: [f32; 3],
@@ -114,9 +119,9 @@ fn main() {
 
 	let scene = prepare_scene(&display);
 
-	let rot = Quat::from_euler(glam::EulerRot::YXZ, std::f32::consts::FRAC_PI_4, 0., 0.);
+	let rot = Quat::from_euler(glam::EulerRot::ZYX, std::f32::consts::FRAC_PI_4, 0., 0.);
 	let mut cur_pos = vec2(0., 0.);
-	let mut cam_pos = rot * vec3(0., 1., -4.);
+	let mut cam_pos = rot * vec3(-200., 0., 50.);
 	let mut cam_rot = DragCtl::new(rot);
 
 	let mut t1 = Instant::now();
@@ -141,25 +146,33 @@ fn main() {
 						let ctl_down =
 							keys_pressed.contains(&PhysicalKey::Code(KeyCode::ShiftLeft));
 						[
-							(ctl_left, vec3(-1., 0., 0.)),
-							(ctl_right, vec3(1., 0., 0.)),
-							(ctl_fwd, vec3(0., 0., 1.)),
-							(ctl_bwd, vec3(0., 0., -1.)),
-							(ctl_up, vec3(0., 1., 0.)),
-							(ctl_down, vec3(0., -1., 0.)),
+							(ctl_left, vec3(0., 1., 0.)),
+							(ctl_right, vec3(0., -1., 0.)),
+							(ctl_fwd, vec3(1., 0., 0.)),
+							(ctl_bwd, vec3(-1., 0., 0.)),
+							(ctl_up, vec3(0., 0., 1.)),
+							(ctl_down, vec3(0., 0., -1.)),
 						]
 						.into_iter()
 						.filter_map(|(ctl, dir)| ctl.then_some(dir))
 						.sum()
 					};
-					cam_pos += 5. * dt * (cam_rot.state() * v);
+					cam_pos += 100. * dt * (cam_rot.state() * v);
 
 					let size = window.inner_size();
 					let size = vec2(size.width as f32, size.height as f32).normalize()
 						* std::f32::consts::SQRT_2;
 					let proj = make_proj_matrix(vec3(size.x, size.y, 2.), (0.125, 1024.125));
 
-					let view = Mat4::from_quat(cam_rot.state().inverse())
+					let my_to_gl = mat4(
+						vec4(0., 0., 1., 0.),
+						vec4(-1., 0., 0., 0.),
+						vec4(0., 1., 0., 0.),
+						vec4(0., 0., 0., 1.),
+					);
+
+					let view = my_to_gl
+						* Mat4::from_quat(cam_rot.state().inverse())
 						* Mat4::from_translation(-cam_pos);
 
 					let mut target = display.draw();
@@ -213,7 +226,7 @@ fn main() {
 					cur_pos = vec2(position.x as f32, position.y as f32) / size.length();
 					cam_rot.on_move(cur_pos, |init, off| {
 						window.request_redraw();
-						init * Quat::from_euler(glam::EulerRot::YXZ, -2. * off.x, -2. * off.y, 0.)
+						init * Quat::from_euler(glam::EulerRot::ZYX, 2. * off.x, -2. * off.y, 0.)
 					});
 				}