From def2ebb3df0e4aee106e8ec242c994c7bcdd429f Mon Sep 17 00:00:00 2001
From: Micha White <botahamec@outlook.com>
Date: Sun, 25 Sep 2022 22:55:35 -0400
Subject: Code simplification + fixed bug

---
 src/camera.rs   | 43 +++++++++++++++++++++++++++----------------
 src/renderer.rs |  2 +-
 2 files changed, 28 insertions(+), 17 deletions(-)

(limited to 'src')

diff --git a/src/camera.rs b/src/camera.rs
index 2eb1730..b594b0f 100644
--- a/src/camera.rs
+++ b/src/camera.rs
@@ -1,4 +1,4 @@
-use cgmath::{Matrix4, Vector3};
+use cgmath::{Matrix4, Vector2};
 
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct Camera {
@@ -46,10 +46,20 @@ impl Camera {
 
 	/// Set the position of the camera
 	pub fn set_position(&mut self, x: f32, y: f32) {
+		debug_assert!(
+			x <= 1000.0 && y <= 1000.0,
+			"The x-position of the camera is ({}, {}), which is too large. \
+			Please keep both the x and y positions below 1000 units. \
+			Otherwise, everything will look crazy. \
+			For an explanation, see https://www.youtube.com/watch?v=Q2OGwnRik24",
+			x,
+			y
+		);
+
 		self.position = (x, y);
 	}
 
-	/// Set the aspect ratio of the camera
+	/// Set the zoom of the camera
 	pub fn set_zoom(&mut self, zoom: f32) {
 		self.zoom = zoom;
 	}
@@ -60,36 +70,37 @@ impl Camera {
 	}
 
 	#[allow(clippy::wrong_self_convention)]
-	pub(crate) fn to_matrix(&mut self) -> [[f32; 4]; 4] {
-		let cos_theta = self.rotation.cos();
-		let sin_theta = self.rotation.sin();
+	pub(crate) fn to_matrix(&mut self) -> CameraUniform {
+		let cos = self.rotation.cos();
+		let sin = self.rotation.sin();
 
-		let x_axis = Vector3::new(cos_theta, -sin_theta, 0.0);
-		let y_axis = Vector3::new(sin_theta, cos_theta, 0.0);
-		let z_axis = Vector3::new(0.0, 0.0, 1.0);
+		let x_axis = Vector2::new(cos, -sin);
+		let y_axis = Vector2::new(sin, cos);
 
-		let eye = Vector3::new(self.position.0, self.position.1, 0.0);
+		let eye = Vector2::new(self.position.0, self.position.1);
 		let x_dot = -cgmath::dot(x_axis, eye);
 		let y_dot = -cgmath::dot(y_axis, eye);
-		let z_dot = -cgmath::dot(z_axis, eye);
 
 		#[rustfmt::skip]
 		let view_matrix = Matrix4::new(
-			x_axis.x, y_axis.x, z_axis.x, 0.0,
-			x_axis.y, y_axis.y, z_axis.y, 0.0,
-			x_axis.x, y_axis.y, z_axis.z, 0.0,
-			x_dot, y_dot, z_dot, 1.0
+			x_axis.x, y_axis.x, 0.0, 0.0,
+			x_axis.y, y_axis.y, 0.0, 0.0,
+			0.0, 0.0, 1.0, 0.0,
+			x_dot, y_dot, 0.0, 1.0
 		);
 
 		#[rustfmt::skip]
 		// TODO implement more scaling coordinate systems
 		let projection_matrix = Matrix4::new(
-			self.inverse_aspect_ratio, 0.0, 0.0, 0.0,
+			self.inverse_aspect_ratio * self.zoom, 0.0, 0.0, 0.0,
 			0.0, self.zoom, 0.0, 0.0,
 			0.0, 0.0, 0.0, 0.0,
 			0.0, 0.0, 0.0, 1.0
 		);
 
-		(projection_matrix * view_matrix).into()
+		self.rotation += 0.01;
+
+		let transform = projection_matrix * view_matrix;
+		transform.into()
 	}
 }
diff --git a/src/renderer.rs b/src/renderer.rs
index 5820f1c..4ac521f 100644
--- a/src/renderer.rs
+++ b/src/renderer.rs
@@ -74,7 +74,7 @@ impl Renderer {
 
 		let adapter = adapter.or_else(|| {
 			instance
-				.enumerate_adapters(wgpu::Backends::all())
+				.enumerate_adapters(wgpu::Backends::PRIMARY)
 				.find(|adapter| !surface.get_supported_formats(adapter).is_empty())
 		});
 
-- 
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