Add a gc step in commit

agb/examples/animated_background.rs

@@ -33,7 +33,7 @@ fn main(mut gba: agb::Gba) -> ! {
         }
     }
 
-    bg.commit();
+    bg.commit(&mut vram);
     bg.show();
 
     let mut i = 0;

agb/examples/chicken.rs

@@ -67,7 +67,7 @@ fn main(mut gba: agb::Gba) -> ! {
     }
 
     background.show();
-    background.commit();
+    background.commit(&mut vram);
 
     let object = gba.display.object.get();
 

agb/examples/dynamic_tiles.rs

@@ -41,7 +41,7 @@ fn main(mut gba: agb::Gba) -> ! {
         }
     }
 
-    bg.commit();
+    bg.commit(&mut vram);
     bg.show();
 
     loop {

agb/examples/text_render.rs

@@ -44,20 +44,20 @@ fn main(mut gba: agb::Gba) -> ! {
 
     writer.commit();
 
-    bg.commit();
+    bg.commit(&mut vram);
     bg.show();
 
     let mut frame = 0;
 
     loop {
-        vblank.wait_for_vblank();
-
         let mut writer = FONT.render_text((4u16, 0u16).into(), 1, 2, &mut bg, &mut vram);
 
         writeln!(&mut writer, "Frame {}", frame).unwrap();
         writer.commit();
-        bg.commit();
 
         frame += 1;
+
+        vblank.wait_for_vblank();
+        bg.commit(&mut vram);
     }
 }

agb/src/display/example_logo.rs

@@ -18,7 +18,7 @@ pub fn display_logo(map: &mut RegularMap, vram: &mut VRamManager) {
         }
     }
 
-    map.commit();
+    map.commit(vram);
     map.show();
 }
 #[cfg(test)]

agb/src/display/font.rs

@@ -242,7 +242,7 @@ mod tests {
 
         writer.commit();
 
-        bg.commit();
+        bg.commit(&mut vram);
         bg.show();
 
         crate::test_runner::assert_image_output("examples/font/font-test-output.png");

agb/src/display/tiled/infinite_scrolled_map.rs

@@ -206,8 +206,8 @@ impl<'a> InfiniteScrolledMap<'a> {
         self.map.hide();
     }
 
-    pub fn commit(&mut self) {
-        self.map.commit();
+    pub fn commit(&mut self, vram: &mut VRamManager) {
+        self.map.commit(vram);
     }
 
     pub fn clear(&mut self, vram: &mut VRamManager) {

agb/src/display/tiled/map.rs

@@ -92,13 +92,15 @@ impl RegularMap {
         DISPLAY_CONTROL.set(new_mode);
     }
 
-    pub fn commit(&mut self) {
+    pub fn commit(&mut self, vram: &mut VRamManager) {
         let new_bg_control_value = (self.priority as u16) | ((self.screenblock as u16) << 8);
 
         self.bg_control_register().set(new_bg_control_value);
         self.bg_h_offset().set(self.x_scroll);
         self.bg_v_offset().set(self.y_scroll);
 
+        vram.gc();
+
         if !self.tiles_dirty {
             return;
         }

agb/src/display/tiled/vram_manager.rs

@@ -158,6 +158,8 @@ impl DynamicTile<'_> {
 pub struct VRamManager {
     tile_set_to_vram: HashMap<TileInTileSetReference, TileReference>,
     reference_counts: Vec<TileReferenceCount>,
+
+    indices_to_gc: Vec<TileIndex>,
 }
 
 impl VRamManager {
@@ -168,6 +170,7 @@ impl VRamManager {
         Self {
             tile_set_to_vram,
             reference_counts: Default::default(),
+            indices_to_gc: Default::default(),
         }
     }
 
@@ -270,18 +273,26 @@ impl VRamManager {
             return;
         }
 
-        let tile_reference = Self::reference_from_index(tile_index);
-        unsafe {
-            TILE_ALLOCATOR.dealloc_no_normalise(tile_reference.0.cast().as_ptr(), TILE_LAYOUT);
+        self.indices_to_gc.push(tile_index);
+    }
+
+    pub(crate) fn gc(&mut self) {
+        for tile_index in self.indices_to_gc.drain(..) {
+            let index = tile_index.index() as usize;
+
+            let tile_reference = Self::reference_from_index(tile_index);
+            unsafe {
+                TILE_ALLOCATOR.dealloc_no_normalise(tile_reference.0.cast().as_ptr(), TILE_LAYOUT);
+            }
+
+            let tile_ref = self.reference_counts[index]
+                .tile_in_tile_set
+                .as_ref()
+                .unwrap();
+
+            self.tile_set_to_vram.remove(tile_ref);
+            self.reference_counts[index].clear();
         }
-
-        let tile_ref = self.reference_counts[index]
-            .tile_in_tile_set
-            .as_ref()
-            .unwrap();
-
-        self.tile_set_to_vram.remove(tile_ref);
-        self.reference_counts[index].clear();
     }
 
     pub fn replace_tile(