Update background and foreground independentently

agb/src/display/background.rs

@@ -25,6 +25,18 @@ const TILE_BACKGROUND: MemoryMapped1DArray<u32, { 2048 * 8 }> =
 const PALETTE_BACKGROUND: MemoryMapped1DArray<u16, 256> =
     unsafe { MemoryMapped1DArray::new(0x0500_0000) };
 
+#[cfg(debug_assertions)]
+const unsafe fn debug_unreachable_unchecked() -> ! {
+    unreachable!();
+}
+
+#[cfg(not(debug_assertions))]
+const unsafe fn debug_unreachable_unchecked() -> ! {
+    use core::hint::unreachable_unchecked;
+
+    unreachable_unchecked();
+}
+
 #[derive(Clone, Copy, Debug)]
 pub enum TileFormat {
     FourBpp,
@@ -72,7 +84,7 @@ impl VRamState {
         if let VRamState::ReferenceCounted(count, _) = self {
             *count += 1;
         } else {
-            panic!("Corrupted vram state");
+            unsafe { debug_unreachable_unchecked() };
         }
     }
 
@@ -81,7 +93,7 @@ impl VRamState {
             *count -= 1;
             (*count, *tile_ref)
         } else {
-            panic!("Corrupted vram state");
+            unsafe { debug_unreachable_unchecked() };
         }
     }
 }
@@ -134,7 +146,7 @@ impl<'a> VRamManager<'a> {
                     self.tilesets[ptr] = tileset;
                     ptr
                 }
-                _ => panic!("Free pointer shouldn't point to valid data"),
+                _ => unsafe { debug_unreachable_unchecked() },
             }
         } else {
             self.tilesets.push(tileset);
@@ -149,7 +161,7 @@ impl<'a> VRamManager<'a> {
 
         match tileset {
             ArenaStorageItem::Data(_, generation) => {
-                assert_eq!(
+                debug_assert_eq!(
                     *generation, tile_set_ref.generation,
                     "Tileset generation must be the same when removing"
                 );
@@ -162,7 +174,7 @@ impl<'a> VRamManager<'a> {
 
                 self.free_pointer = Some(tile_set_ref.id as usize);
             }
-            _ => panic!("Already freed, probably a double free?"),
+            _ => unsafe { debug_unreachable_unchecked() },
         }
     }
 
@@ -182,7 +194,7 @@ impl<'a> VRamManager<'a> {
                         self.vram_free_pointer = Some(next_free as usize);
                     }
                 }
-                VRamState::ReferenceCounted(_, _) => panic!("Corrupted tile reference state"),
+                VRamState::ReferenceCounted(_, _) => unsafe { debug_unreachable_unchecked() },
             }
 
             self.references[ptr] = VRamState::ReferenceCounted(1, tile_ref);
@@ -196,7 +208,7 @@ impl<'a> VRamManager<'a> {
         let tile_slice = if let ArenaStorageItem::Data(data, generation) =
             &self.tilesets[tile_set_ref.id as usize]
         {
-            assert_eq!(
+            debug_assert_eq!(
                 *generation, tile_set_ref.generation,
                 "Stale tile data requested"
             );
@@ -204,7 +216,7 @@ impl<'a> VRamManager<'a> {
             let tile_offset = (tile as usize) * data.format.tile_size() / 4;
             &data.tiles[tile_offset..(tile_offset + data.format.tile_size() / 4)]
         } else {
-            panic!("Cannot find tile data at given reference");
+            unsafe { debug_unreachable_unchecked() };
         };
 
         let tile_size_in_words = TileFormat::FourBpp.tile_size() / 4;

examples/the-hat-chooses-the-wizard/Cargo.lock

@@ -25,6 +25,7 @@ dependencies = [
  "bare-metal",
  "bitflags",
  "hashbrown",
+ "rustc-hash",
 ]
 
 [[package]]
@@ -89,12 +90,6 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f8fe8f5a8a398345e52358e18ff07cc17a568fbca5c6f73873d3a62056309603"
 
-[[package]]
-name = "bare-metal"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f8fe8f5a8a398345e52358e18ff07cc17a568fbca5c6f73873d3a62056309603"
-
 [[package]]
 name = "bitflags"
 version = "1.3.2"
@@ -103,9 +98,9 @@ checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
 [[package]]
 name = "bytemuck"
-version = "1.7.3"
+version = "1.8.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "439989e6b8c38d1b6570a384ef1e49c8848128f5a97f3914baef02920842712f"
+checksum = "0e851ca7c24871e7336801608a4797d7376545b6928a10d32d75685687141ead"
 
 [[package]]
 name = "byteorder"
@@ -248,15 +243,15 @@ dependencies = [
 
 [[package]]
 name = "once_cell"
-version = "1.9.0"
+version = "1.10.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "da32515d9f6e6e489d7bc9d84c71b060db7247dc035bbe44eac88cf87486d8d5"
+checksum = "87f3e037eac156d1775da914196f0f37741a274155e34a0b7e427c35d2a2ecb9"
 
 [[package]]
 name = "png"
-version = "0.17.4"
+version = "0.17.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "02cd7d51cea7e2fa6bbcb8af5fbcad15b871451bfc2d20ed72dff2f4ae072a84"
+checksum = "dc38c0ad57efb786dd57b9864e5b18bae478c00c824dc55a38bbc9da95dde3ba"
 dependencies = [
  "bitflags",
  "crc32fast",
@@ -318,6 +313,12 @@ dependencies = [
  "getrandom",
 ]
 
+[[package]]
+name = "rustc-hash"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
+
 [[package]]
 name = "ryu"
 version = "1.0.9"

examples/the-hat-chooses-the-wizard/src/main.rs

@@ -285,8 +285,11 @@ impl<'a, 'b> Map<'a, 'b> {
         self.foreground.commit();
     }
 
-    pub fn init(&mut self, vram: &mut VRamManager) {
+    pub fn init_background(&mut self, vram: &mut VRamManager) {
         self.background.init(vram, self.position.floor());
+    }
+
+    pub fn init_foreground(&mut self, vram: &mut VRamManager) {
         self.foreground.init(vram, self.position.floor());
     }
 }
@@ -874,7 +877,13 @@ fn main(mut agb: agb::Gba) -> ! {
                 agb::input::ButtonController::new(),
             );
 
-            level.background.init(&mut vram);
+            level.background.init_background(&mut vram);
+            music_box.before_frame(&mut mixer);
+            mixer.frame();
+            vblank.wait_for_vblank();
+            mixer.after_vblank();
+
+            level.background.init_foreground(&mut vram);
 
             for _ in 0..60 {
                 music_box.before_frame(&mut mixer);