Add super simple animated tiles

agb/examples/animated_background.rs

@@ -0,0 +1,48 @@
+#![no_std]
+#![no_main]
+
+use agb::{
+    display::{
+        tiled::{TileFormat, TileSet, TileSetting},
+        Priority,
+    },
+    include_gfx,
+};
+
+include_gfx!("examples/water_tiles.toml");
+
+#[agb::entry]
+fn main(mut gba: agb::Gba) -> ! {
+    let (gfx, mut vram) = gba.display.video.tiled0();
+    let vblank = agb::interrupt::VBlank::get();
+
+    let tileset = TileSet::new(water_tiles::water_tiles.tiles, TileFormat::FourBpp);
+    let tileset_ref = vram.add_tileset(tileset);
+
+    vram.set_background_palettes(water_tiles::water_tiles.palettes);
+
+    let mut bg = gfx.background(Priority::P0);
+
+    for y in 0..20u16 {
+        for x in 0..30u16 {
+            bg.set_tile(
+                &mut vram,
+                (x, y).into(),
+                tileset_ref,
+                TileSetting::new(0, false, false, 0),
+            );
+        }
+    }
+
+    bg.commit();
+    bg.show();
+
+    let mut i = 0;
+    loop {
+        i = (i + 1) % 8;
+
+        vram.replace_tile(tileset_ref, 0, tileset_ref, i);
+
+        vblank.wait_for_vblank();
+    }
+}

agb/examples/water_tiles.toml

@@ -0,0 +1,5 @@
+version = "1.0"
+
+[image.water_tiles]
+filename = "water_tiles.png"
+tile_size = "8x8"

agb/src/display/tiled/vram_manager.rs

@@ -177,6 +177,45 @@ impl<'a> VRamManager<'a> {
         TileReference(NonNull::new(ptr as *mut _).unwrap())
     }
 
+    pub fn replace_tile(
+        &mut self,
+        source_tile_set_ref: TileSetReference,
+        source_tile: u16,
+        target_tile_set_ref: TileSetReference,
+        target_tile: u16,
+    ) {
+        if let Some(&reference) = self
+            .tile_set_to_vram
+            .get(&(source_tile_set_ref.id, source_tile))
+        {
+            let tile_slice = if let ArenaStorageItem::Data(data, generation) =
+                &self.tilesets[target_tile_set_ref.id as usize]
+            {
+                debug_assert_eq!(
+                    *generation, target_tile_set_ref.generation,
+                    "Stale tile data requested"
+                );
+
+                let tile_offset = (target_tile as usize) * data.format.tile_size();
+                &data.tiles[tile_offset..(tile_offset + data.format.tile_size())]
+            } else {
+                panic!("Target tile set ref must point to an existing tile set reference")
+            };
+
+            let tile_size_in_half_words = tile_slice.len() / 2;
+
+            let target_location = reference.0.as_ptr() as *mut _;
+
+            unsafe {
+                dma_copy16(
+                    tile_slice.as_ptr() as *const u16,
+                    target_location,
+                    tile_size_in_half_words,
+                )
+            };
+        }
+    }
+
     pub(crate) fn add_tile(&mut self, tile_set_ref: TileSetReference, tile: u16) -> TileIndex {
         let reference = self.tile_set_to_vram.get(&(tile_set_ref.id, tile));