From d4b61dd34b06119e87c8932ab7718d432dbc6a4f Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Wed, 22 May 2024 20:39:26 +0200
Subject: feat(engine): add point light attenuation

---
 engine/src/lighting.rs     | 23 +++++++++++++++++++++++
 engine/src/renderer/mod.rs | 21 +++++++++++++++++++++
 2 files changed, 44 insertions(+)

(limited to 'engine/src')

diff --git a/engine/src/lighting.rs b/engine/src/lighting.rs
index bfc2d9b..ffa2645 100644
--- a/engine/src/lighting.rs
+++ b/engine/src/lighting.rs
@@ -11,6 +11,7 @@ pub struct PointLight
 {
     pub diffuse: Color<f32>,
     pub specular: Color<f32>,
+    pub attenuation_params: AttenuationParams,
 }
 }
 
@@ -29,6 +30,7 @@ impl Default for PointLight
         Self {
             diffuse: Color { red: 0.5, green: 0.5, blue: 0.5 },
             specular: Color { red: 1.0, green: 1.0, blue: 1.0 },
+            attenuation_params: AttenuationParams::default(),
         }
     }
 }
@@ -41,6 +43,27 @@ impl Default for PointLightBuilder
     }
 }
 
+/// Parameters for light [attenuation](https://en.wikipedia.org/wiki/Attenuation).
+#[derive(Debug, Clone)]
+pub struct AttenuationParams
+{
+    pub constant: f32,
+    pub linear: f32,
+    pub quadratic: f32,
+}
+
+impl Default for AttenuationParams
+{
+    fn default() -> Self
+    {
+        Self {
+            constant: 1.0,
+            linear: 0.0,
+            quadratic: 0.0,
+        }
+    }
+}
+
 builder! {
 /// Global light properties.
 #[builder(name = GlobalLightBuilder, derives = (Debug, Clone, Default))]
diff --git a/engine/src/renderer/mod.rs b/engine/src/renderer/mod.rs
index e736165..ad587b5 100644
--- a/engine/src/renderer/mod.rs
+++ b/engine/src/renderer/mod.rs
@@ -389,6 +389,27 @@ fn apply_light(
             .into(),
     );
 
+    gl_shader_program.set_uniform_1fv(
+        cstr!("light.constant"),
+        point_light.map_or(1.0, |(light_source, _)| {
+            light_source.attenuation_params.constant
+        }),
+    );
+
+    gl_shader_program.set_uniform_1fv(
+        cstr!("light.linear"),
+        point_light.map_or(0.0, |(light_source, _)| {
+            light_source.attenuation_params.linear
+        }),
+    );
+
+    gl_shader_program.set_uniform_1fv(
+        cstr!("light.quadratic"),
+        point_light.map_or(0.0, |(light_source, _)| {
+            light_source.attenuation_params.quadratic
+        }),
+    );
+
     gl_shader_program.set_uniform_vec_3fv(
         cstr!("material.ambient"),
         &if material_flags.use_ambient_color {
-- 
cgit v1.2.3-18-g5258