From 9778d9668f8b5d651aaed1f64414f7ed195d153d Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Mon, 15 Apr 2024 23:09:11 +0200
Subject: feat(engine): add projection options to camera component

---
 engine/src/camera.rs       |  3 +++
 engine/src/lib.rs          |  2 +-
 engine/src/projection.rs   | 56 +++++++++++++++++++++++++++++++++++++---------
 engine/src/renderer/mod.rs | 14 ++++++------
 4 files changed, 57 insertions(+), 18 deletions(-)

(limited to 'engine')

diff --git a/engine/src/camera.rs b/engine/src/camera.rs
index 5347e83..640c1f4 100644
--- a/engine/src/camera.rs
+++ b/engine/src/camera.rs
@@ -1,5 +1,6 @@
 use ecs::Component;
 
+use crate::projection::{Perspective, Projection};
 use crate::vector::Vec3;
 
 #[derive(Debug, Component)]
@@ -9,6 +10,7 @@ pub struct Camera
     pub target: Vec3<f32>,
     pub global_up: Vec3<f32>,
     pub current: bool,
+    pub projection: Projection,
 }
 
 impl Default for Camera
@@ -20,6 +22,7 @@ impl Default for Camera
             target: Vec3::default(),
             global_up: Vec3::UP,
             current: false,
+            projection: Projection::Perspective(Perspective::default()),
         }
     }
 }
diff --git a/engine/src/lib.rs b/engine/src/lib.rs
index f83d85b..b3f4aa1 100644
--- a/engine/src/lib.rs
+++ b/engine/src/lib.rs
@@ -18,7 +18,6 @@ use crate::event::{
 };
 
 mod opengl;
-mod projection;
 mod shader_preprocessor;
 
 pub mod camera;
@@ -30,6 +29,7 @@ pub mod lighting;
 pub mod material;
 pub mod math;
 pub mod mesh;
+pub mod projection;
 pub mod renderer;
 pub mod shader;
 pub mod texture;
diff --git a/engine/src/projection.rs b/engine/src/projection.rs
index d5186ba..aa84a9f 100644
--- a/engine/src/projection.rs
+++ b/engine/src/projection.rs
@@ -1,20 +1,56 @@
 use crate::matrix::Matrix;
 
-/// Creates a new perspective projection matrix.
-#[must_use]
-pub fn new_perspective(
-    fov_radians: f32,
+#[derive(Debug)]
+#[non_exhaustive]
+pub enum Projection
+{
+    Perspective(Perspective),
+}
+
+/// Perspective projection parameters.
+#[derive(Debug)]
+pub struct Perspective
+{
+    pub fov_radians: f32,
+    pub far: f32,
+    pub near: f32,
+}
+
+impl Default for Perspective
+{
+    fn default() -> Self
+    {
+        Self {
+            fov_radians: 80.0f32.to_radians(),
+            far: 100.0,
+            near: 0.1,
+        }
+    }
+}
+
+pub(crate) fn new_perspective_matrix(
+    perspective: &Perspective,
     aspect: f32,
-    far: f32,
-    near: f32,
 ) -> Matrix<f32, 4, 4>
 {
     let mut out = Matrix::new();
 
-    out.set_cell(0, 0, (1.0 / (fov_radians / 2.0).tan()) / aspect);
-    out.set_cell(1, 1, 1.0 / (fov_radians / 2.0).tan());
-    out.set_cell(2, 2, (near + far) / (near - far));
-    out.set_cell(2, 3, (2.0 * near * far) / (near - far));
+    out.set_cell(0, 0, (1.0 / (perspective.fov_radians / 2.0).tan()) / aspect);
+
+    out.set_cell(1, 1, 1.0 / (perspective.fov_radians / 2.0).tan());
+
+    out.set_cell(
+        2,
+        2,
+        (perspective.near + perspective.far) / (perspective.near - perspective.far),
+    );
+
+    out.set_cell(
+        2,
+        3,
+        (2.0 * perspective.near * perspective.far) / (perspective.near - perspective.far),
+    );
+
     out.set_cell(3, 2, -1.0);
 
     out
diff --git a/engine/src/renderer/mod.rs b/engine/src/renderer/mod.rs
index 617c60f..3052969 100644
--- a/engine/src/renderer/mod.rs
+++ b/engine/src/renderer/mod.rs
@@ -35,7 +35,7 @@ use crate::opengl::vertex_array::{
     VertexArray,
 };
 use crate::opengl::{clear_buffers, enable, BufferClearMask, Capability};
-use crate::projection::new_perspective;
+use crate::projection::{new_perspective_matrix, Projection};
 use crate::shader::Program as ShaderProgram;
 use crate::texture::{Id as TextureId, List as TextureMap, Texture};
 use crate::transform::Transform;
@@ -321,12 +321,12 @@ fn apply_transformation_matrices(
     gl_shader_program.set_uniform_matrix_4fv(cstr!("view"), &view);
 
     #[allow(clippy::cast_precision_loss)]
-    let projection = new_perspective(
-        80.0f32.to_radians(),
-        window_size.width as f32 / window_size.height as f32,
-        100.0,
-        0.1,
-    );
+    let projection = match &camera.projection {
+        Projection::Perspective(perspective) => new_perspective_matrix(
+            perspective,
+            window_size.width as f32 / window_size.height as f32,
+        ),
+    };
 
     gl_shader_program.set_uniform_matrix_4fv(cstr!("projection"), &projection);
 }
-- 
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