Expand transform buffers when they're full

src/render/renderer.rs

@@ -57,12 +57,16 @@ struct TransformBufferIndices {
 }
 
 struct TransformBuffers {
+    //transform_layout: wgpu::BindGroupLayout,
     /// A vector storing the EntityId and 
     just_updated: HashMap<EntityId, TransformBufferIndices>,
     not_updated: HashMap<EntityId, TransformBufferIndices>,
     dead_indices: VecDeque<TransformBufferIndices>,
     next_indices: TransformBufferIndices,
-    buffer_bindgroups: Vec<(wgpu::Buffer, wgpu::BindGroup)>,
+    /// (transform count, buffer, bindgroup)
+    buffer_bindgroups: Vec<(usize, wgpu::Buffer, wgpu::BindGroup)>,
+    /// The max amount of transforms in a buffer
+    max_transform_count: usize,
 }
 
 impl TransformBuffers {
@@ -72,25 +76,31 @@ impl TransformBuffers {
             .expect("Use 'insert_entity' for new entities");
         self.just_updated.insert(entity, indices);
 
-        let (buffer, _) = self.buffer_bindgroups.get(indices.buffer_index).unwrap();
+        let (_, buffer, _) = self.buffer_bindgroups.get(indices.buffer_index).unwrap();
         queue.write_buffer(buffer, indices.transform_index as u64 * limits.min_uniform_buffer_offset_alignment as u64, bytemuck::bytes_of(&transform));
     }
 
     /// Insert a new entity into the buffer, returns where it was stored.
     fn insert_entity(&mut self, queue: &wgpu::Queue, limits: &Limits, entity: EntityId, transform: glam::Mat4) -> TransformBufferIndices {
         // get a dead index, or create a new one
-        let indices = if let Some(index) = self.dead_indices.pop_front() {
-            index
+        let (indices, buffer) = if let Some(index) = self.dead_indices.pop_front() {
+            let (_, buffer, _) = self.buffer_bindgroups.get(index.buffer_index).unwrap();
+            (index, &*buffer)
         } else {
-            // TODO: Create new buffer if this one is full
             let indices = &mut self.next_indices;
-            let new = indices.clone();
+            let this_idx = indices.clone();
+            let (count, buffer, _) = self.buffer_bindgroups.get_mut(indices.buffer_index).unwrap();
+
+            if count.clone() >= self.max_transform_count {
+                panic!("Transform buffer is filled and 'next_indices' was not incremented! Was a new buffer created?");
+            }
+
+            *count += 1;
             indices.transform_index += 1;
 
-            new
+            (this_idx, &*buffer)
         };
-
-        let (buffer, _) = self.buffer_bindgroups.get(indices.buffer_index).unwrap();
+        
         queue.write_buffer(buffer, Self::get_offset_for(limits, indices), bytemuck::bytes_of(&transform));
 
         self.just_updated.insert(entity, indices);
@@ -112,6 +122,15 @@ impl TransformBuffers {
     fn get_offset_for(limits: &Limits, indices: TransformBufferIndices) -> u64 {
         indices.transform_index as u64 * limits.min_uniform_buffer_offset_alignment as u64
     }
+
+    /// Returns whether or not the transform buffers should be expanded
+    fn should_expand(&self) -> bool {
+        if let Some(( count, _, _ )) = self.buffer_bindgroups.last() {
+            count.clone() >= self.max_transform_count
+        } else {
+            true
+        }
+    }
 }
 
 pub struct BasicRenderer {
@@ -280,7 +299,8 @@ impl BasicRenderer {
         // create create the transform buffer storage
         //let transforms = AVec::new(render_limits.min_uniform_buffer_offset_alignment as usize);
         let transform_buffers = TransformBuffers {
-            buffer_bindgroups: vec![( transform_buffer, transform_bind_group )],
+            max_transform_count: (render_limits.max_uniform_buffer_binding_size / mem::size_of::<glam::Mat4>() as u32) as usize,
+            buffer_bindgroups: vec![( 0, transform_buffer, transform_bind_group )],
             just_updated: HashMap::new(),
             not_updated: HashMap::new(),
             dead_indices: VecDeque::new(),
@@ -438,6 +458,42 @@ impl BasicRenderer {
             transform_index: transform_indices
         }
     }
+
+    fn expand_transform_buffers(&mut self) -> TransformBufferIndices {
+        let buffers = &mut self.transform_buffers;
+
+        let transform_buffer = self.device.create_buffer(
+            &wgpu::BufferDescriptor {
+                label: Some(&format!("Transform Buffer {}", buffers.buffer_bindgroups.len())),
+                usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
+                size: self.render_limits.max_uniform_buffer_binding_size as u64,
+                mapped_at_creation: false,
+            }
+        );
+
+        let stride = self.render_limits.min_uniform_buffer_offset_alignment as usize + mem::size_of::<glam::Mat4>();
+        let transform_bind_group = self.device.create_bind_group(&wgpu::BindGroupDescriptor {
+            layout: &self.transform_bind_group_layout,
+            entries: &[
+                wgpu::BindGroupEntry {
+                    binding: 0,
+                    resource: wgpu::BindingResource::Buffer(
+                            wgpu::BufferBinding {
+                            buffer: &transform_buffer,
+                            offset: 0,
+                            size: Some(NonZeroU64::new(stride as u64).unwrap())
+                        }
+                    )
+                }
+            ],
+            label: Some("transform_bind_group"),
+        });
+
+        let indices = TransformBufferIndices { buffer_index: buffers.buffer_bindgroups.len(), transform_index: 0 };
+        buffers.buffer_bindgroups.push(( 0, transform_buffer, transform_bind_group ));
+        buffers.next_indices = indices;
+        indices
+    }
 }
 
 impl Renderer for BasicRenderer {
@@ -448,15 +504,25 @@ impl Renderer for BasicRenderer {
             let job = RenderJob::new(model.mesh.clone(), model.material.clone(), entity, transform.transform, None);
             self.render_jobs.push_back(job);
 
-            if self.buffer_storage.get(&entity).is_none() {
+            if self.buffer_storage.get(&entity).is_none() { // TODO: Delete dead entites from buffer_storage
+                // check if the transform buffers need to be expanded
+                if self.transform_buffers.should_expand() {
+                    self.expand_transform_buffers();
+                }
+
+                // insert transform into buffers
                 let indices = self.transform_buffers.insert_entity(&self.queue, &self.render_limits,
                     entity, transform.transform.calculate_mat4());
 
+                // create the mesh's buffers
                 let buffers = self.create_model_buffers(model, indices);
                 self.buffer_storage.insert(entity, buffers);
             } else {
+                // update entity transforms
                 self.transform_buffers.update_entity(&self.queue, &self.render_limits,
                     entity, transform.transform.calculate_mat4());
+
+                // TODO: Update model buffers in storage
             }
         }
 
@@ -512,7 +578,7 @@ impl Renderer for BasicRenderer {
 
                     // Get the bindgroup for job's transform and bind to it using an offset.
                     let transform_indices = buffers.transform_index;
-                    let (_, bindgroup) = self.transform_buffers.buffer_bindgroups.get(transform_indices.buffer_index).unwrap();
+                    let (_, _, bindgroup) = self.transform_buffers.buffer_bindgroups.get(transform_indices.buffer_index).unwrap();
                     let offset = TransformBuffers::get_offset_for(&self.render_limits, transform_indices);
                     render_pass.set_bind_group(1, bindgroup, &[ offset as u32, ]);