Deallocate atlas entries and remove padding

wgpu/src/image.rs

@@ -415,10 +415,10 @@ impl Pipeline {
 
     pub fn trim_cache(&mut self) {
         #[cfg(feature = "image")]
-        self.raster_cache.borrow_mut().trim();
+        self.raster_cache.borrow_mut().trim(&mut self.texture_atlas);
 
         #[cfg(feature = "svg")]
-        self.vector_cache.borrow_mut().trim();
+        self.vector_cache.borrow_mut().trim(&mut self.texture_atlas);
     }
 }
 
@@ -531,8 +531,8 @@ fn add_instance(
             (y as f32 + 0.5) / atlas::SIZE as f32,
         ],
         _size_in_atlas: [
-            (width as f32 - 0.5) / atlas::SIZE as f32,
-            (height as f32 - 0.5) / atlas::SIZE as f32,
+            (width as f32 - 1.0) / atlas::SIZE as f32,
+            (height as f32 - 1.0) / atlas::SIZE as f32,
         ],
         _layer: layer as u32,
     };

wgpu/src/image/raster.rs

@@ -95,10 +95,21 @@ impl Cache {
         }
     }
 
-    pub fn trim(&mut self) {
+    pub fn trim(&mut self, atlas: &mut Atlas) {
         let hits = &self.hits;
 
-        self.map.retain(|k, _| hits.contains(k));
+        self.map.retain(|k, memory| {
+            let retain = hits.contains(k);
+
+            if !retain {
+                if let Memory::Device(entry) = memory {
+                    atlas.remove(entry);
+                }
+            }
+
+            retain
+        });
+
         self.hits.clear();
     }
 

wgpu/src/image/vector.rs

@@ -130,12 +130,20 @@ impl Cache {
         }
     }
 
-    pub fn trim(&mut self) {
+    pub fn trim(&mut self, atlas: &mut Atlas) {
         let svg_hits = &self.svg_hits;
         let rasterized_hits = &self.rasterized_hits;
 
         self.svgs.retain(|k, _| svg_hits.contains(k));
-        self.rasterized.retain(|k, _| rasterized_hits.contains(k));
+        self.rasterized.retain(|k, entry| {
+            let retain = rasterized_hits.contains(k);
+
+            if !retain {
+                atlas.remove(entry);
+            }
+
+            retain
+        });
         self.svg_hits.clear();
         self.rasterized_hits.clear();
     }

wgpu/src/texture/atlas.rs

@@ -112,11 +112,47 @@ impl Atlas {
             }
         }
 
-        log::info!("Current atlas: {:?}", &self);
+        log::info!("Current atlas: {:?}", self);
 
         Some(entry)
     }
 
+    pub fn remove(&mut self, entry: &Entry) {
+        log::info!("Removing atlas entry: {:?}", entry);
+
+        match entry {
+            Entry::Contiguous(allocation) => {
+                self.deallocate(allocation);
+            }
+            Entry::Fragmented { fragments, .. } => {
+                for fragment in fragments {
+                    self.deallocate(&fragment.allocation);
+                }
+            }
+        }
+    }
+
+    fn deallocate(&mut self, allocation: &Allocation) {
+        log::info!("Deallocating atlas: {:?}", allocation);
+
+        match allocation {
+            Allocation::Full { layer } => {
+                self.layers[*layer] = Layer::Empty;
+            }
+            Allocation::Partial { layer, region } => {
+                let layer = &mut self.layers[*layer];
+
+                if let Layer::Busy(allocator) = layer {
+                    allocator.deallocate(region);
+
+                    if allocator.is_empty() {
+                        *layer = Layer::Empty;
+                    }
+                }
+            }
+        }
+    }
+
     fn allocate(&mut self, width: u32, height: u32) -> Option<Entry> {
         // Allocate one layer if texture fits perfectly
         if width == SIZE && height == SIZE {

wgpu/src/texture/atlas/allocator.rs

@@ -2,70 +2,54 @@ use guillotiere::{AtlasAllocator, Size};
 
 pub struct Allocator {
     raw: AtlasAllocator,
-    size: u32,
+    allocations: usize,
 }
 
 impl Allocator {
-    const PADDING: u32 = 1;
-
     pub fn new(size: u32) -> Allocator {
         let raw = AtlasAllocator::new(Size::new(size as i32, size as i32));
 
-        Allocator { raw, size }
+        Allocator {
+            raw,
+            allocations: 0,
+        }
     }
 
     pub fn allocate(&mut self, width: u32, height: u32) -> Option<Region> {
-        let padding = (
-            if width + Self::PADDING * 2 < self.size {
-                Self::PADDING
-            } else {
-                0
-            },
-            if height + Self::PADDING * 2 < self.size {
-                Self::PADDING
-            } else {
-                0
-            },
-        );
+        let allocation =
+            self.raw.allocate(Size::new(width as i32, height as i32))?;
 
-        let allocation = self.raw.allocate(Size::new(
-            (width + padding.0 * 2) as i32,
-            (height + padding.1 * 2) as i32,
-        ))?;
+        self.allocations += 1;
 
-        Some(Region {
-            allocation,
-            padding,
-        })
+        Some(Region { allocation })
     }
 
-    pub fn deallocate(&mut self, region: Region) {
+    pub fn deallocate(&mut self, region: &Region) {
         self.raw.deallocate(region.allocation.id);
+
+        self.allocations = self.allocations.saturating_sub(1);
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.allocations == 0
     }
 }
 
 pub struct Region {
     allocation: guillotiere::Allocation,
-    padding: (u32, u32),
 }
 
 impl Region {
     pub fn position(&self) -> (u32, u32) {
         let rectangle = &self.allocation.rectangle;
 
-        (
-            rectangle.min.x as u32 + self.padding.0,
-            rectangle.min.y as u32 + self.padding.1,
-        )
+        (rectangle.min.x as u32, rectangle.min.y as u32)
     }
 
     pub fn size(&self) -> (u32, u32) {
         let size = self.allocation.rectangle.size();
 
-        (
-            size.width as u32 - self.padding.0 * 2,
-            size.height as u32 - self.padding.1 * 2,
-        )
+        (size.width as u32, size.height as u32)
     }
 }
 
@@ -80,7 +64,6 @@ impl std::fmt::Debug for Region {
         f.debug_struct("Region")
             .field("id", &self.allocation.id)
             .field("rectangle", &self.allocation.rectangle)
-            .field("padding", &self.padding)
             .finish()
     }
 }