Merge pull request #101 from corwinkuiper/sane-backgrounds

Sane backgrounds

agb/examples/chicken.rs

@@ -3,7 +3,7 @@
 
 extern crate agb;
 use agb::{
-    display::{object::ObjectStandard, HEIGHT, WIDTH},
+    display::{background::Map, object::ObjectStandard, HEIGHT, WIDTH},
     input::Button,
 };
 use core::convert::TryInto;
@@ -48,18 +48,19 @@ fn main() -> ! {
     let vblank = agb::interrupt::VBlank::get();
     let mut input = agb::input::ButtonController::new();
 
-    gfx.set_sprite_palette_raw(&CHICKEN_PALETTE);
-    gfx.set_sprite_tilemap(&CHICKEN_TILES);
-
     gfx.set_background_palette_raw(&MAP_PALETTE);
     gfx.set_background_tilemap(0, &MAP_TILES);
 
-    let mut background = gfx.get_background().unwrap();
+    let mut background = gfx.get_regular().unwrap();
-    background.draw_full_map(&MAP_MAP, (32_u32, 32_u32).into(), 0);
+    background.set_map(Map::new(&MAP_MAP, (32_u32, 32_u32).into(), 0));
     background.show();
+    background.commit();
 
     let mut object = gba.display.object.get();
 
+    object.set_sprite_palette_raw(&CHICKEN_PALETTE);
+    object.set_sprite_tilemap(&CHICKEN_TILES);
+
     object.enable();
     let mut chicken = Character {
         object: object.get_object_standard(),

agb/src/display/background.rs

@@ -0,0 +1,401 @@
+use core::ops::Index;
+
+use crate::{
+    memory_mapped::{MemoryMapped, MemoryMapped1DArray},
+    number::{Rect, Vector2D},
+};
+
+use super::{
+    palette16, set_graphics_mode, set_graphics_settings, DisplayMode, GraphicsSettings, Priority,
+    DISPLAY_CONTROL,
+};
+
+const PALETTE_BACKGROUND: MemoryMapped1DArray<u16, 256> =
+    unsafe { MemoryMapped1DArray::new(0x0500_0000) };
+
+const TILE_BACKGROUND: MemoryMapped1DArray<u32, { 2048 * 8 }> =
+    unsafe { MemoryMapped1DArray::new(0x06000000) };
+
+const MAP: *mut [[[u16; 32]; 32]; 32] = 0x0600_0000 as *mut _;
+
+pub enum ColourMode {
+    FourBitPerPixel = 0,
+    EightBitPerPixel = 1,
+}
+
+#[derive(Clone, Copy)]
+pub enum BackgroundSize {
+    S32x32 = 0,
+    S64x32 = 1,
+    S32x64 = 2,
+    S64x64 = 3,
+}
+
+#[derive(PartialEq, Eq, Clone, Copy)]
+enum Mutability {
+    Immutable,
+    Mutable,
+}
+
+struct MapStorage<'a> {
+    s: *const [u16],
+    mutability: Mutability,
+    _phantom: core::marker::PhantomData<&'a ()>,
+}
+
+impl<'a> Index<usize> for MapStorage<'a> {
+    type Output = u16;
+    fn index(&self, index: usize) -> &Self::Output {
+        &self.get()[index]
+    }
+}
+
+impl<'a> MapStorage<'a> {
+    fn new(store: &[u16]) -> MapStorage {
+        MapStorage {
+            s: store as *const _,
+            mutability: Mutability::Immutable,
+            _phantom: core::marker::PhantomData,
+        }
+    }
+    fn new_mutable(store: &mut [u16]) -> MapStorage {
+        MapStorage {
+            s: store as *const _,
+            mutability: Mutability::Mutable,
+            _phantom: core::marker::PhantomData,
+        }
+    }
+    fn get(&self) -> &[u16] {
+        unsafe { &*self.s }
+    }
+    fn get_mut(&mut self) -> &mut [u16] {
+        assert!(
+            self.mutability == Mutability::Mutable,
+            "backing storage must be mutable in order to get internal storage mutably"
+        );
+        unsafe { &mut *(self.s as *mut _) }
+    }
+}
+
+/// The map background is the method of drawing game maps to the screen. It
+/// automatically handles copying the correct portion of a provided map to the
+/// assigned block depending on given coordinates.
+pub struct BackgroundRegular<'a> {
+    background: u8,
+    block: u8,
+    commited_position: Vector2D<i32>,
+    shadowed_position: Vector2D<i32>,
+    poisoned: bool,
+    shadowed_register: u16,
+    copy_size: Vector2D<u16>,
+    background_size: BackgroundSize,
+    map: Option<Map<'a>>,
+}
+
+pub struct Map<'a> {
+    store: MapStorage<'a>,
+    pub dimensions: Vector2D<u32>,
+    pub default: u16,
+}
+
+impl<'a> Map<'a> {
+    pub fn new(map: &[u16], dimensions: Vector2D<u32>, default: u16) -> Map {
+        Map {
+            store: MapStorage::new(map),
+            dimensions,
+            default,
+        }
+    }
+    pub fn new_mutable(map: &mut [u16], dimensions: Vector2D<u32>, default: u16) -> Map {
+        Map {
+            store: MapStorage::new_mutable(map),
+            dimensions,
+            default,
+        }
+    }
+    fn get_position(&self, x: i32, y: i32) -> u16 {
+        if x < 0 || x as u32 >= self.dimensions.x || y < 0 || y as u32 >= self.dimensions.y {
+            self.default
+        } else {
+            self.store[y as usize * self.dimensions.x as usize + x as usize]
+        }
+    }
+    pub fn get_store(&self) -> &[u16] {
+        self.store.get()
+    }
+    pub fn get_mutable_store(&mut self) -> &mut [u16] {
+        self.store.get_mut()
+    }
+}
+
+impl<'a> BackgroundRegular<'a> {
+    unsafe fn new(background: u8, block: u8, size: BackgroundSize) -> BackgroundRegular<'a> {
+        let mut b = BackgroundRegular {
+            background,
+            block,
+            commited_position: (0, 0).into(),
+            shadowed_position: (0, 0).into(),
+            shadowed_register: 0,
+            copy_size: (30_u16, 20_u16).into(),
+            background_size: size,
+            poisoned: true,
+            map: None,
+        };
+        b.set_block(block);
+        b.set_colour_mode(ColourMode::FourBitPerPixel);
+        b.set_background_size(size);
+        b
+    }
+
+    /// Sets the background to be shown on screen. Requires the background to
+    /// have a map enabled otherwise a panic is caused.
+    pub fn show(&mut self) {
+        assert!(self.map.is_some());
+        let mode = DISPLAY_CONTROL.get();
+        let new_mode = mode | (1 << (self.background + 0x08));
+        DISPLAY_CONTROL.set(new_mode);
+    }
+
+    /// Hides the background, nothing from this background is rendered to screen.
+    pub fn hide(&mut self) {
+        let mode = DISPLAY_CONTROL.get();
+        let new_mode = mode & !(1 << (self.background + 0x08));
+        DISPLAY_CONTROL.set(new_mode);
+    }
+
+    unsafe fn set_shadowed_register_bits(&mut self, value: u16, length: u16, shift: u16) {
+        let mask = !(((1 << length) - 1) << shift);
+        let new = (self.shadowed_register & mask) | (value << shift);
+        self.shadowed_register = new;
+    }
+
+    unsafe fn get_register(&self) -> MemoryMapped<u16> {
+        MemoryMapped::new(0x0400_0008 + 2 * self.background as usize)
+    }
+
+    unsafe fn set_block(&mut self, block: u8) {
+        self.set_shadowed_register_bits(block as u16, 5, 0x8);
+    }
+
+    unsafe fn set_colour_mode(&mut self, mode: ColourMode) {
+        self.set_shadowed_register_bits(mode as u16, 0x1, 0x7);
+    }
+
+    pub fn set_priority(&mut self, p: Priority) {
+        unsafe { self.set_shadowed_register_bits(p as u16, 0x2, 0x0) };
+    }
+
+    unsafe fn set_background_size(&mut self, size: BackgroundSize) {
+        self.set_shadowed_register_bits(size as u16, 0x2, 0xE);
+    }
+
+    unsafe fn set_position_x_register(&self, x: u16) {
+        *((0x0400_0010 + 4 * self.background as usize) as *mut u16) = x
+    }
+    unsafe fn set_position_y_register(&self, y: u16) {
+        *((0x0400_0012 + 4 * self.background as usize) as *mut u16) = y
+    }
+
+    pub fn set_position(&mut self, position: Vector2D<i32>) {
+        self.shadowed_position = position;
+    }
+
+    pub fn get_map(&mut self) -> Option<&mut Map<'a>> {
+        self.poisoned = true;
+        self.map.as_mut()
+    }
+
+    pub fn set_map(&mut self, map: Map<'a>) {
+        self.poisoned = true;
+        self.map = Some(map);
+    }
+
+    pub fn commit(&mut self) {
+        // commit shadowed register
+        unsafe { self.get_register().set(self.shadowed_register) };
+
+        let commited_screen = Rect::new(self.commited_position, self.copy_size.change_base());
+        let shadowed_screen = Rect::new(self.shadowed_position, self.copy_size.change_base());
+
+        if self.poisoned || !shadowed_screen.touches(commited_screen) {
+            let positions_to_be_updated = Rect::new(
+                self.shadowed_position / 8 - (1, 1).into(),
+                self.copy_size.change_base() + (1, 1).into(),
+            )
+            .iter();
+
+            if let Some(map) = &self.map {
+                for (x, y) in positions_to_be_updated {
+                    unsafe {
+                        (&mut (*MAP)[self.block as usize][y.rem_euclid(32) as usize]
+                            [x.rem_euclid(32) as usize] as *mut u16)
+                            .write_volatile(map.get_position(x, y));
+                    }
+                }
+            }
+        } else {
+            let commited_block = self.commited_position / 8;
+            let shadowed_block = self.shadowed_position / 8;
+
+            let top_bottom_rect: Rect<i32> = {
+                let top_bottom_height = commited_block.y - shadowed_block.y;
+                let new_y = if top_bottom_height < 0 {
+                    commited_block.y + self.copy_size.y as i32
+                } else {
+                    shadowed_block.y
+                };
+                Rect::new(
+                    (shadowed_block.x, new_y).into(),
+                    (30, top_bottom_height.abs()).into(),
+                )
+            };
+
+            let left_right_rect: Rect<i32> = {
+                let left_right_width = commited_block.x - shadowed_block.x;
+                let new_x = if left_right_width < 0 {
+                    commited_block.x + self.copy_size.x as i32
+                } else {
+                    shadowed_block.x
+                };
+                Rect::new(
+                    (new_x, shadowed_block.y).into(),
+                    (left_right_width.abs(), 20).into(),
+                )
+            };
+
+            if let Some(map) = &self.map {
+                for (x, y) in top_bottom_rect.iter().chain(left_right_rect.iter()) {
+                    unsafe {
+                        (&mut (*MAP)[self.block as usize][y.rem_euclid(32) as usize]
+                            [x.rem_euclid(32) as usize] as *mut u16)
+                            .write_volatile(map.get_position(x, y));
+                    }
+                }
+            }
+        };
+
+        // update commited position
+
+        self.commited_position = self.shadowed_position;
+
+        self.poisoned = false;
+
+        // update position in registers
+
+        unsafe {
+            self.set_position_x_register((self.commited_position.x % (32 * 8)) as u16);
+            self.set_position_y_register((self.commited_position.y % (32 * 8)) as u16);
+        }
+    }
+}
+
+fn decide_background_mode(num_regular: u8, num_affine: u8) -> Option<DisplayMode> {
+    if num_affine == 0 && num_regular <= 4 {
+        Some(DisplayMode::Tiled0)
+    } else if num_affine == 1 && num_regular <= 2 {
+        Some(DisplayMode::Tiled1)
+    } else if num_affine == 2 && num_regular == 0 {
+        Some(DisplayMode::Tiled2)
+    } else {
+        None
+    }
+}
+
+pub struct BackgroundDistributor {
+    used_blocks: u32,
+    num_regular: u8,
+    num_affine: u8,
+}
+
+impl<'b> BackgroundDistributor {
+    pub(crate) unsafe fn new() -> Self {
+        set_graphics_settings(GraphicsSettings::empty() | GraphicsSettings::SPRITE1_D);
+        set_graphics_mode(DisplayMode::Tiled0);
+        BackgroundDistributor {
+            used_blocks: 0,
+            num_regular: 0,
+            num_affine: 0,
+        }
+    }
+
+    fn set_background_tilemap_entry(&mut self, index: u32, data: u32) {
+        TILE_BACKGROUND.set(index as usize, data);
+    }
+
+    /// Copies raw palettes to the background palette without any checks.
+    pub fn set_background_palette_raw(&mut self, palette: &[u16]) {
+        for (index, &colour) in palette.iter().enumerate() {
+            PALETTE_BACKGROUND.set(index, colour);
+        }
+    }
+
+    fn set_background_palette(&mut self, pal_index: u8, palette: &palette16::Palette16) {
+        for (colour_index, &colour) in palette.colours.iter().enumerate() {
+            PALETTE_BACKGROUND.set(pal_index as usize * 16 + colour_index, colour);
+        }
+    }
+
+    /// Copies palettes to the background palettes without any checks.
+    pub fn set_background_palettes(&mut self, palettes: &[palette16::Palette16]) {
+        for (palette_index, entry) in palettes.iter().enumerate() {
+            self.set_background_palette(palette_index as u8, entry)
+        }
+    }
+
+    /// Gets a map background if possible and assigns an unused block to it.
+    pub fn get_regular(&mut self) -> Result<BackgroundRegular<'b>, &'static str> {
+        let new_mode = decide_background_mode(self.num_regular + 1, self.num_affine)
+            .ok_or("there is no mode compatible with the requested backgrounds")?;
+
+        unsafe { set_graphics_mode(new_mode) };
+
+        if !self.used_blocks == 0 {
+            return Err("all blocks are used");
+        }
+
+        let mut availiable_block = u8::MAX;
+
+        for i in 0..32 {
+            if (1 << i) & self.used_blocks == 0 {
+                availiable_block = i;
+                break;
+            }
+        }
+
+        assert!(
+            availiable_block != u8::MAX,
+            "should be able to find a block"
+        );
+
+        self.used_blocks |= 1 << availiable_block;
+
+        let background = self.num_regular;
+        self.num_regular += 1;
+        Ok(unsafe { BackgroundRegular::new(background, availiable_block, BackgroundSize::S32x32) })
+    }
+
+    /// Copies tiles to tilemap starting at the starting tile. Cannot overwrite
+    /// blocks that are already written to, panic is caused if this is attempted.
+    pub fn set_background_tilemap(&mut self, start_tile: u32, tiles: &[u32]) {
+        let u32_per_block = 512;
+
+        let start_block = (start_tile * 8) / u32_per_block;
+        // round up rather than down
+        let end_block = (start_tile * 8 + tiles.len() as u32 + u32_per_block - 1) / u32_per_block;
+
+        let blocks_to_use: u32 = ((1 << (end_block - start_block)) - 1) << start_block;
+
+        assert!(
+            self.used_blocks & blocks_to_use == 0,
+            "blocks {} to {} should be unused for this copy to succeed",
+            start_block,
+            end_block
+        );
+
+        self.used_blocks |= blocks_to_use;
+
+        for (index, &tile) in tiles.iter().enumerate() {
+            self.set_background_tilemap_entry(start_tile * 8 + index as u32, tile)
+        }
+    }
+}

agb/src/display/example_logo.rs

@@ -1,12 +1,13 @@
-use crate::display::tiled0::Tiled0;
+use crate::display::background::BackgroundDistributor;
 
 crate::include_gfx!("gfx/agb_logo.toml");
 
-pub fn display_logo(gfx: &mut Tiled0) {
+pub fn display_logo(gfx: &mut BackgroundDistributor) {
+    use super::background::Map;
     gfx.set_background_palettes(agb_logo::test_logo.palettes);
     gfx.set_background_tilemap(0, agb_logo::test_logo.tiles);
 
-    let mut back = gfx.get_background().unwrap();
+    let mut back = gfx.get_regular().unwrap();
 
     let mut entries: [u16; 30 * 20] = [0; 30 * 20];
     for tile_id in 0..(30 * 20) {
@@ -14,8 +15,9 @@ pub fn display_logo(gfx: &mut Tiled0) {
         entries[tile_id as usize] = tile_id | (palette_entry << 12);
     }
 
-    back.draw_full_map(&entries, (30_u32, 20_u32).into(), 0);
+    back.set_map(Map::new(&entries, (30_u32, 20_u32).into(), 0));
     back.show();
+    back.commit();
 }
 
 #[test_case]

agb/src/display/mod.rs

@@ -5,6 +5,8 @@ use video::Video;
 
 use self::object::ObjectControl;
 
+/// Graphics mode 0. Four regular backgrounds.
+pub mod background;
 /// Graphics mode 3. Bitmap mode that provides a 16-bit colour framebuffer.
 pub mod bitmap3;
 /// Graphics mode 4. Bitmap 4 provides two 8-bit paletted framebuffers with page switching.
@@ -17,8 +19,6 @@ pub mod object;
 pub mod palette16;
 /// Data produced by agb-image-converter
 pub mod tile_data;
-/// Graphics mode 0. Four regular backgrounds.
-pub mod tiled0;
 /// Giving out graphics mode.
 pub mod video;
 

agb/src/display/object.rs

@@ -1,12 +1,16 @@
 use core::cell::RefCell;
 
-use super::{Priority, DISPLAY_CONTROL};
+use super::{palette16, Priority, DISPLAY_CONTROL};
 use crate::bitarray::Bitarray;
 use crate::memory_mapped::MemoryMapped1DArray;
 use crate::number::Vector2D;
 
 const OBJECT_ATTRIBUTE_MEMORY: MemoryMapped1DArray<u16, 512> =
     unsafe { MemoryMapped1DArray::new(0x0700_0000) };
+const PALETTE_SPRITE: MemoryMapped1DArray<u16, 256> =
+    unsafe { MemoryMapped1DArray::new(0x0500_0200) };
+const TILE_SPRITE: MemoryMapped1DArray<u32, { 512 * 8 }> =
+    unsafe { MemoryMapped1DArray::new(0x06010000) };
 
 /// Handles distributing objects and matricies along with operations that effect all objects.
 pub struct ObjectControl {
@@ -311,6 +315,39 @@ impl ObjectControl {
         }
     }
 
+    fn set_sprite_tilemap_entry(&self, index: usize, data: u32) {
+        TILE_SPRITE.set(index, data);
+    }
+
+    /// Copies raw palettes to the background palette without any checks.
+    pub fn set_sprite_palette_raw(&self, colour: &[u16]) {
+        for (index, &entry) in colour.iter().enumerate() {
+            self.set_sprite_palette_entry(index, entry)
+        }
+    }
+    fn set_sprite_palette_entry(&self, index: usize, colour: u16) {
+        PALETTE_SPRITE.set(index, colour)
+    }
+
+    fn set_sprite_palette(&self, pal_index: u8, palette: &palette16::Palette16) {
+        for (colour_index, &colour) in palette.colours.iter().enumerate() {
+            PALETTE_SPRITE.set(pal_index as usize * 16 + colour_index, colour);
+        }
+    }
+
+    pub fn set_sprite_palettes(&self, palettes: &[palette16::Palette16]) {
+        for (palette_index, entry) in palettes.iter().enumerate() {
+            self.set_sprite_palette(palette_index as u8, entry)
+        }
+    }
+
+    /// Copies tiles to the sprite tilemap without any checks.
+    pub fn set_sprite_tilemap(&self, tiles: &[u32]) {
+        for (index, &tile) in tiles.iter().enumerate() {
+            self.set_sprite_tilemap_entry(index, tile)
+        }
+    }
+
     /// Enable objects on the GBA.
     pub fn enable(&mut self) {
         let disp = DISPLAY_CONTROL.get();

agb/src/display/tiled0.rs

@@ -1,430 +0,0 @@
-use core::{convert::TryInto, ops::Deref};
-
-use crate::{
-    memory_mapped::MemoryMapped1DArray,
-    number::{Rect, Vector2D},
-};
-
-use super::{
-    palette16, set_graphics_mode, set_graphics_settings, DisplayMode, GraphicsSettings, Priority,
-    DISPLAY_CONTROL,
-};
-
-const PALETTE_BACKGROUND: MemoryMapped1DArray<u16, 256> =
-    unsafe { MemoryMapped1DArray::new(0x0500_0000) };
-const PALETTE_SPRITE: MemoryMapped1DArray<u16, 256> =
-    unsafe { MemoryMapped1DArray::new(0x0500_0200) };
-
-const TILE_BACKGROUND: MemoryMapped1DArray<u32, { 2048 * 8 }> =
-    unsafe { MemoryMapped1DArray::new(0x06000000) };
-const TILE_SPRITE: MemoryMapped1DArray<u32, { 512 * 8 }> =
-    unsafe { MemoryMapped1DArray::new(0x06010000) };
-
-const MAP: *mut [[[u16; 32]; 32]; 32] = 0x0600_0000 as *mut _;
-
-pub enum ColourMode {
-    FourBitPerPixel = 0,
-    EightBitPerPixel = 1,
-}
-
-pub enum BackgroundSize {
-    S32x32 = 0,
-    S64x32 = 1,
-    S32x64 = 2,
-    S64x64 = 3,
-}
-
-#[non_exhaustive]
-/// The map background is the method of drawing game maps to the screen. It
-/// automatically handles copying the correct portion of a provided map to the
-/// assigned block depending on given coordinates.
-pub struct Background {
-    background: u8,
-    block: u8,
-    pos_x: i32,
-    pos_y: i32,
-}
-
-impl Background {
-    unsafe fn new(layer: u8, block: u8) -> Background {
-        let mut background = Background {
-            background: layer,
-            block,
-            pos_x: 0,
-            pos_y: 0,
-        };
-        background.set_colour_mode(ColourMode::FourBitPerPixel);
-        background.set_background_size(BackgroundSize::S32x32);
-        background.set_block(block);
-        background
-    }
-}
-
-impl Background {
-    /// Sets the background to be shown on screen. Requires the background to
-    /// have a map enabled otherwise a panic is caused.
-    pub fn show(&mut self) {
-        let mode = DISPLAY_CONTROL.get();
-        let new_mode = mode | (1 << (self.background + 0x08));
-        DISPLAY_CONTROL.set(new_mode);
-    }
-
-    /// Hides the background, nothing from this background is rendered to screen.
-    pub fn hide(&mut self) {
-        let mode = DISPLAY_CONTROL.get();
-        let new_mode = mode & !(1 << (self.background + 0x08));
-        DISPLAY_CONTROL.set(new_mode);
-    }
-
-    unsafe fn get_register(&mut self) -> *mut u16 {
-        (0x0400_0008 + 2 * self.background as usize) as *mut u16
-    }
-
-    unsafe fn set_block(&mut self, block: u8) {
-        self.set_bits(0x08, 5, block as u16)
-    }
-
-    unsafe fn set_bits(&mut self, start: u16, num_bits: u16, bits: u16) {
-        let reg = self.get_register();
-        let control = reg.read_volatile();
-        let mask = !(((1 << num_bits) - 1) << start);
-        let new_control = (control & mask) | ((bits as u16) << start);
-        reg.write_volatile(new_control);
-    }
-
-    /// Sets priority of the background layer. Backgrounds with higher priority
-    /// are drawn (above/below) backgrounds with lower priority.
-    pub fn set_priority(&mut self, p: Priority) {
-        unsafe { self.set_bits(0, 2, p as u16) }
-    }
-
-    fn set_colour_mode(&mut self, mode: ColourMode) {
-        unsafe { self.set_bits(0x07, 1, mode as u16) }
-    }
-
-    fn set_background_size(&mut self, size: BackgroundSize) {
-        unsafe { self.set_bits(0x0E, 2, size as u16) }
-    }
-
-    fn map_get<T>(&self, map: &T, dim_x: u32, dim_y: u32, x: i32, y: i32, default: u16) -> u16
-    where
-        T: Deref<Target = [u16]>,
-    {
-        if x >= dim_x as i32 || x < 0 || y >= dim_y as i32 || y < 0 {
-            default
-        } else {
-            map[(dim_x as i32 * y + x) as usize]
-        }
-    }
-
-    fn set_x(&self, x: u16) {
-        unsafe { ((0x0400_0010 + 4 * self.background as usize) as *mut u16).write_volatile(x) }
-    }
-    fn set_y(&self, y: u16) {
-        unsafe { ((0x0400_0012 + 4 * self.background as usize) as *mut u16).write_volatile(y) }
-    }
-
-    /// Forces the portion of the map in current view to be copied to the map
-    /// block assigned to this background. This is currently unnecesary to call.
-    /// Setting position already updates the drawn map, and changing map forces
-    /// an update.
-    pub fn draw_full_map(&mut self, map: &[u16], dimensions: Vector2D<u32>, default: u16) {
-        let area: Rect<i32> = Rect {
-            position: Vector2D::new(-1, -1),
-            size: Vector2D::new(32, 22),
-        };
-        self.draw_area(map, dimensions, area, default);
-    }
-
-    /// Forces a specific area of the screen to be drawn, taking into account any positonal offsets.
-    pub fn draw_area(&self, map: &[u16], dimensions: Vector2D<u32>, area: Rect<i32>, default: u16) {
-        self.draw_area_mapped(
-            &map,
-            dimensions.x,
-            dimensions.y,
-            area.position.x,
-            area.position.y,
-            area.size.x,
-            area.size.y,
-            default,
-        );
-    }
-
-    #[allow(clippy::too_many_arguments)]
-    fn draw_area_mapped<T>(
-        &self,
-        map: &T,
-        dim_x: u32,
-        dim_y: u32,
-        left: i32,
-        top: i32,
-        width: i32,
-        height: i32,
-        default: u16,
-    ) where
-        T: Deref<Target = [u16]>,
-    {
-        let x_map_space = self.pos_x / 8;
-        let y_map_space = self.pos_y / 8;
-
-        let x_block_space = x_map_space % 32;
-        let y_block_space = y_map_space % 32;
-
-        for x in left..(left + width) {
-            for y in top..(top + height) {
-                unsafe {
-                    (&mut (*MAP)[self.block as usize][(y_block_space + y).rem_euclid(32) as usize]
-                        [(x_block_space + x).rem_euclid(32) as usize]
-                        as *mut u16)
-                        .write_volatile(self.map_get(
-                            map,
-                            dim_x,
-                            dim_y,
-                            x_map_space + x,
-                            y_map_space + y,
-                            default,
-                        ))
-                };
-            }
-        }
-    }
-
-    pub fn set_offset(&mut self, position: Vector2D<u32>) {
-        self.set_x(position.x as u16);
-        self.set_y(position.y as u16);
-    }
-
-    /// Sets the position of the map to be shown on screen. This automatically
-    /// manages copying the correct portion to the map block and moving the map
-    /// registers.
-    pub fn set_position(
-        &mut self,
-        map: &[u16],
-        dimensions: Vector2D<u32>,
-        position: Vector2D<i32>,
-        default: u16,
-    ) {
-        self.set_position_mapped(
-            &map,
-            dimensions.x,
-            dimensions.y,
-            position.x,
-            position.y,
-            default,
-        );
-    }
-
-    fn set_position_mapped<T>(
-        &mut self,
-        map: &T,
-        dim_x: u32,
-        dim_y: u32,
-        x: i32,
-        y: i32,
-        default: u16,
-    ) where
-        T: Deref<Target = [u16]>,
-    {
-        let x_map_space = x / 8;
-        let y_map_space = y / 8;
-
-        let prev_x_map_space = self.pos_x / 8;
-        let prev_y_map_space = self.pos_y / 8;
-
-        let x_difference = x_map_space - prev_x_map_space;
-        let y_difference = y_map_space - prev_y_map_space;
-
-        let x_block_space = x_map_space % 32;
-        let y_block_space = y_map_space % 32;
-
-        self.pos_x = x;
-        self.pos_y = y;
-
-        // don't fancily handle if we've moved more than one tile, just copy the whole new map
-        if x_difference.abs() > 1 || y_difference.abs() > 1 {
-            self.draw_area_mapped(map, dim_x, dim_y, -1, -1, 32, 22, default);
-        } else {
-            if x_difference != 0 {
-                let x_offset = match x_difference {
-                    -1 => -1,
-                    1 => 30,
-                    _ => unreachable!(),
-                };
-                for y in -1..21 {
-                    unsafe {
-                        (&mut (*MAP)[self.block as usize]
-                            [(y_block_space + y).rem_euclid(32) as usize]
-                            [(x_block_space + x_offset).rem_euclid(32) as usize]
-                            as *mut u16)
-                            .write_volatile(self.map_get(
-                                map,
-                                dim_x,
-                                dim_y,
-                                x_map_space + x_offset,
-                                y_map_space + y,
-                                default,
-                            ))
-                    };
-                }
-            }
-            if y_difference != 0 {
-                let y_offset = match y_difference {
-                    -1 => -1,
-                    1 => 20,
-                    _ => unreachable!(),
-                };
-                for x in -1..31 {
-                    unsafe {
-                        (&mut (*MAP)[self.block as usize]
-                            [(y_block_space + y_offset).rem_euclid(32) as usize]
-                            [(x_block_space + x).rem_euclid(32) as usize]
-                            as *mut u16)
-                            .write_volatile(self.map_get(
-                                map,
-                                dim_x,
-                                dim_y,
-                                x_map_space + x,
-                                y_map_space + y_offset,
-                                default,
-                            ))
-                    };
-                }
-            }
-        }
-
-        let x_remainder = x % (32 * 8);
-        let y_remainder = y % (32 * 8);
-
-        self.set_x(x_remainder as u16);
-        self.set_y(y_remainder as u16);
-    }
-}
-
-#[non_exhaustive]
-pub struct Tiled0 {
-    used_blocks: u32,
-    num_backgrounds: u8,
-}
-
-impl Tiled0 {
-    pub(crate) unsafe fn new() -> Self {
-        set_graphics_settings(GraphicsSettings::empty() | GraphicsSettings::SPRITE1_D);
-        set_graphics_mode(DisplayMode::Tiled0);
-        Tiled0 {
-            used_blocks: 0,
-            num_backgrounds: 0,
-        }
-    }
-
-    fn set_sprite_palette_entry(&mut self, index: u8, colour: u16) {
-        PALETTE_SPRITE.set(index as usize, colour)
-    }
-    fn set_sprite_tilemap_entry(&mut self, index: u32, data: u32) {
-        TILE_SPRITE.set(index as usize, data);
-    }
-
-    fn set_background_tilemap_entry(&mut self, index: u32, data: u32) {
-        TILE_BACKGROUND.set(index as usize, data);
-    }
-
-    /// Copies raw palettes to the background palette without any checks.
-    pub fn set_sprite_palette_raw(&mut self, colour: &[u16]) {
-        for (index, &entry) in colour.iter().enumerate() {
-            self.set_sprite_palette_entry(index.try_into().unwrap(), entry)
-        }
-    }
-    fn set_sprite_palette(&mut self, pal_index: u8, palette: &palette16::Palette16) {
-        for (colour_index, &colour) in palette.colours.iter().enumerate() {
-            PALETTE_SPRITE.set(pal_index as usize * 16 + colour_index, colour);
-        }
-    }
-
-    pub fn set_sprite_palettes(&mut self, palettes: &[palette16::Palette16]) {
-        for (palette_index, entry) in palettes.iter().enumerate() {
-            self.set_sprite_palette(palette_index as u8, entry)
-        }
-    }
-
-    /// Copies raw palettes to the background palette without any checks.
-    pub fn set_background_palette_raw(&mut self, palette: &[u16]) {
-        for (index, &colour) in palette.iter().enumerate() {
-            PALETTE_BACKGROUND.set(index, colour);
-        }
-    }
-
-    fn set_background_palette(&mut self, pal_index: u8, palette: &palette16::Palette16) {
-        for (colour_index, &colour) in palette.colours.iter().enumerate() {
-            PALETTE_BACKGROUND.set(pal_index as usize * 16 + colour_index, colour);
-        }
-    }
-
-    /// Copies palettes to the background palettes without any checks.
-    pub fn set_background_palettes(&mut self, palettes: &[palette16::Palette16]) {
-        for (palette_index, entry) in palettes.iter().enumerate() {
-            self.set_background_palette(palette_index as u8, entry)
-        }
-    }
-
-    /// Copies tiles to the sprite tilemap without any checks.
-    pub fn set_sprite_tilemap(&mut self, tiles: &[u32]) {
-        for (index, &tile) in tiles.iter().enumerate() {
-            self.set_sprite_tilemap_entry(index as u32, tile)
-        }
-    }
-
-    /// Gets a map background if possible and assigns an unused block to it.
-    pub fn get_background(&mut self) -> Result<Background, &'static str> {
-        if self.num_backgrounds >= 4 {
-            return Err("too many backgrounds created, maximum is 4");
-        }
-
-        if !self.used_blocks == 0 {
-            return Err("all blocks are used");
-        }
-
-        let mut availiable_block = u8::MAX;
-
-        for i in 0..32 {
-            if (1 << i) & self.used_blocks == 0 {
-                availiable_block = i;
-                break;
-            }
-        }
-
-        assert!(
-            availiable_block != u8::MAX,
-            "should be able to find a block"
-        );
-
-        self.used_blocks |= 1 << availiable_block;
-
-        let background = self.num_backgrounds;
-        self.num_backgrounds = background + 1;
-        Ok(unsafe { Background::new(background, availiable_block) })
-    }
-
-    /// Copies tiles to tilemap starting at the starting tile. Cannot overwrite
-    /// blocks that are already written to, panic is caused if this is attempted.
-    pub fn set_background_tilemap(&mut self, start_tile: u32, tiles: &[u32]) {
-        let u32_per_block = 512;
-
-        let start_block = (start_tile * 8) / u32_per_block;
-        // round up rather than down
-        let end_block = (start_tile * 8 + tiles.len() as u32 + u32_per_block - 1) / u32_per_block;
-
-        let blocks_to_use: u32 = ((1 << (end_block - start_block)) - 1) << start_block;
-
-        assert!(
-            self.used_blocks & blocks_to_use == 0,
-            "blocks {} to {} should be unused for this copy to succeed",
-            start_block,
-            end_block
-        );
-
-        self.used_blocks |= blocks_to_use;
-
-        for (index, &tile) in tiles.iter().enumerate() {
-            self.set_background_tilemap_entry(start_tile * 8 + index as u32, tile)
-        }
-    }
-}

agb/src/display/video.rs

@@ -1,4 +1,4 @@
-use super::{bitmap3::Bitmap3, bitmap4::Bitmap4, tiled0::Tiled0};
+use super::{background::BackgroundDistributor, bitmap3::Bitmap3, bitmap4::Bitmap4};
 
 #[non_exhaustive]
 pub struct Video {}
@@ -14,7 +14,7 @@ impl Video {
         unsafe { Bitmap4::new() }
     }
 
-    pub fn tiled0(&mut self) -> Tiled0 {
+    pub fn tiled0(&mut self) -> BackgroundDistributor {
-        unsafe { Tiled0::new() }
+        unsafe { BackgroundDistributor::new() }
     }
 }

agb/src/number.rs

@@ -648,6 +648,83 @@ impl<T: Number> Rect<T> {
     pub fn new(position: Vector2D<T>, size: Vector2D<T>) -> Self {
         Rect { position, size }
     }
+
+    pub fn contains_point(&self, point: Vector2D<T>) -> bool {
+        point.x > self.position.x
+            && point.x < self.position.x + self.size.x
+            && point.y > self.position.y
+            && point.y < self.position.y + self.size.y
+    }
+
+    pub fn touches(self, other: Rect<T>) -> bool {
+        self.position.x < other.position.x + other.size.x
+            && self.position.x + self.size.x > other.position.x
+            && self.position.y < other.position.y + other.size.y
+            && self.position.y + self.size.y > self.position.y
+    }
+
+    pub fn overlapping_rect(&self, other: Rect<T>) -> Rect<T> {
+        fn max<E: Number>(x: E, y: E) -> E {
+            if x > y {
+                x
+            } else {
+                y
+            }
+        }
+        fn min<E: Number>(x: E, y: E) -> E {
+            if x > y {
+                y
+            } else {
+                x
+            }
+        }
+
+        let top_left: Vector2D<T> = (
+            max(self.position.x, other.position.x),
+            max(self.position.y, other.position.y),
+        )
+            .into();
+        let bottom_right: Vector2D<T> = (
+            min(
+                self.position.x + self.size.x,
+                other.position.x + other.size.x,
+            ),
+            min(
+                self.position.y + self.size.y,
+                other.position.y + other.size.y,
+            ),
+        )
+            .into();
+
+        Rect::new(top_left, bottom_right - top_left)
+    }
+}
+
+impl<T: FixedWidthUnsignedInteger> Rect<T> {
+    pub fn iter(self) -> impl Iterator<Item = (T, T)> {
+        let mut current_x = self.position.x;
+        let mut current_y = self.position.y;
+        let mut is_done = false;
+        core::iter::from_fn(move || {
+            if is_done {
+                None
+            } else {
+                let (old_x, old_y) = (current_x, current_y);
+
+                current_x = current_x + T::one();
+                if current_x > self.position.x + self.size.x {
+                    current_x = self.position.x;
+                    current_y = current_y + T::one();
+                }
+
+                if current_y > self.position.y + self.size.y {
+                    is_done = true;
+                }
+
+                Some((old_x, old_y))
+            }
+        })
+    }
 }
 
 impl<T: Number> Vector2D<T> {