From e23d4dc731adced94a673a4487caa50031d01458 Mon Sep 17 00:00:00 2001
From: SeanOMik <seanomik@gmail.com>
Date: Sun, 12 Nov 2023 15:07:52 -0500
Subject: [PATCH] Fix a possible bug

---
 src/render/light/mod.rs | 27 ++++++++++++++++++---------
 1 file changed, 18 insertions(+), 9 deletions(-)

diff --git a/src/render/light/mod.rs b/src/render/light/mod.rs
index 8f084d1..67de61c 100644
--- a/src/render/light/mod.rs
+++ b/src/render/light/mod.rs
@@ -16,8 +16,12 @@ pub struct LightBuffer<U: Default + bytemuck::Pod + bytemuck::Zeroable> {
     _phantom: PhantomData<U>,
     /// The max amount of light casters that could fit in this buffer.
     pub max_count: usize,
-    /// The current amount of light casters in this buffer.
-    pub current_count: usize,
+    /// The amount of light casters that are taking up space in the buffer.
+    /// 
+    /// This means that a light may be inactive in the buffer, by being replaced
+    /// with a default caster as to not affect lighting. Its easier this way than
+    /// to recreate the array and remove the gaps.
+    pub buffer_count: usize,
     /// The buffer index for a specific entity/caster.
     used_indexes: HashMap<edict::EntityId, usize>,
     /// Indexes that were being used but are no longer needed.
@@ -29,7 +33,7 @@ impl<U: Default + bytemuck::Pod + bytemuck::Zeroable> LightBuffer<U> {
         Self {
             _phantom: PhantomData::default(),
             max_count,
-            current_count: 0,
+            buffer_count: 0,
             used_indexes: HashMap::new(),
             dead_indexes: VecDeque::new(),
         }
@@ -52,8 +56,13 @@ impl<U: Default + bytemuck::Pod + bytemuck::Zeroable> LightBuffer<U> {
         let buffer_idx = match self.dead_indexes.pop_front() {
             Some(i) => i,
             None => {
-                let i = self.current_count;
-                self.current_count += 1;
+                let i = self.buffer_count;
+                self.buffer_count += 1;
+
+                // If this assert triggers, you are hitting trying to exceed
+                // the max amount of lights
+                assert!(self.buffer_count <= self.max_count);
+
                 i
             },
         };
@@ -75,7 +84,7 @@ impl<U: Default + bytemuck::Pod + bytemuck::Zeroable> LightBuffer<U> {
     pub fn remove_light(&mut self, lights_buffer: &mut [U; MAX_LIGHT_COUNT], entity: edict::EntityId) -> bool {
         if let Some(removed_idx) = self.used_indexes.remove(&entity) {
             self.dead_indexes.push_back(removed_idx);
-            self.current_count -= 1;
+            //self.current_count -= 1;
             lights_buffer[removed_idx] = U::default();
 
             true
@@ -99,7 +108,7 @@ impl LightUniformBuffers {
             &wgpu::BufferDescriptor {
                 label: Some("Lights Uniform buffer"),
                 usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
-                size: mem::size_of::<LightsUniform>() as u64,
+                size: (mem::size_of::<LightsUniform>() * MAX_LIGHT_COUNT) as u64,
                 mapped_at_creation: false,
             }
         );
@@ -129,7 +138,7 @@ impl LightUniformBuffers {
                             wgpu::BufferBinding {
                             buffer: &buffer,
                             offset: 0,
-                            size: Some(NonZeroU64::new(mem::size_of::<LightsUniform>() as u64).unwrap())
+                            size: None, // use the full buffer
                         }
                     )
                 }
@@ -158,7 +167,7 @@ impl LightUniformBuffers {
             }
         }
 
-        self.lights_uniform.point_light_count = self.point_lights.current_count as u32;
+        self.lights_uniform.point_light_count = self.point_lights.buffer_count as u32;
         queue.write_buffer(&self.buffer, 0, bytemuck::cast_slice(&[self.lights_uniform]));
     }
 }