chicken object added

examples/chicken.rs

@@ -2,19 +2,33 @@
 #![feature(start)]
 
 extern crate gba;
+use core::convert::{Into, TryInto};
+use gba::{
+    display::{object::ObjectStandard, tiled0, HEIGHT, WIDTH},
+    number::Num,
+};
 
-use gba::display::tiled0;
+struct Character {
+    object: ObjectStandard,
+    position: Vector2D,
+    velocity: Vector2D,
+}
 
 struct Vector2D {
     x: i32,
     y: i32,
 }
 
+fn frame_ranger(count: u32, start: u32, end: u32, delay: u32) -> u32 {
+    ((count / delay) % (end + 1 - start)) + start
+}
+
 #[start]
 fn main(_argc: isize, _argv: *const *const u8) -> isize {
     let mut gba = gba::Gba::new();
     let mut gfx = gba.display.video.tiled0();
     let vblank = gba.display.vblank.get();
+    let mut input = gba::input::ButtonController::new();
 
     gfx.set_sprite_palette(&CHICKEN_PALETTE);
     gfx.set_sprite_tilemap(&CHICKEN_TILES);
@@ -33,8 +47,75 @@ fn main(_argc: isize, _argv: *const *const u8) -> isize {
     gfx.background_0.set_screen_base_block(1);
     gfx.copy_to_map(1, &MAP_MAP);
 
+    let mut object = gfx.object;
+
+    object.enable();
+    unsafe { object.clear_objects() };
+    let mut chicken = Character {
+        object: object.get_object(0),
+        position: Vector2D {
+            x: 20 << 8,
+            y: 20 << 8,
+        },
+        velocity: Vector2D { x: 0, y: 0 },
+    };
+
+    chicken.object.set_tile_id(0);
+    chicken
+        .object
+        .set_x((chicken.position.x >> 8).try_into().unwrap());
+    chicken
+        .object
+        .set_y((chicken.position.y >> 8).try_into().unwrap());
+    chicken.object.commit();
+
+    let acceleration = 1 << 8;
+    let mut frame_count = 0;
+
     loop {
         vblank.wait_for_VBlank();
+        frame_count += 1;
+
+        input.update();
+
+        // Horizontal movement
+        chicken.velocity.x += (input.x_tri() as i32) * acceleration;
+        chicken.velocity.x = 10 * chicken.velocity.x / 16;
+
+        // Update position based on velocity
+        chicken.position.x += chicken.velocity.x;
+        chicken.position.y += chicken.velocity.y;
+
+        // Ensure the chicken remains within bounds
+        chicken.position.x = chicken.position.x.clamp(0, (WIDTH - 8) << 8);
+        chicken.position.y = chicken.position.y.clamp(0, (HEIGHT - 8) << 8);
+
+        // Update direction the chicken is facing
+        if chicken.velocity.x > 1 {
+            chicken.object.set_hflip(false);
+        } else if chicken.velocity.x < -1 {
+            chicken.object.set_hflip(true);
+        }
+
+        // Update the frame of the chicken
+        if (chicken.velocity.x != 0) {
+            chicken
+                .object
+                .set_tile_id(frame_ranger(frame_count, 1, 3, 10));
+        } else {
+            chicken.object.set_tile_id(0);
+        }
+
+        // Update the position of the chicken
+        chicken
+            .object
+            .set_x((chicken.position.x >> 8).try_into().unwrap());
+        chicken
+            .object
+            .set_y((chicken.position.y >> 8).try_into().unwrap());
+
+        // Commit the chicken to vram
+        chicken.object.commit();
     }
 }
 

src/display/object.rs

@@ -1,12 +1,134 @@
-#[non_exhaustive]
-pub struct Object {}
+use super::DISPLAY_CONTROL;
 
-impl Object {
-    pub(crate) fn new() -> Self {
-        Object {}
+const OBJECT_MEMORY_STANDARD: *mut [ObjectAttributeStandard; 128] = 0x0700_0000 as *mut [_; 128];
+
+#[non_exhaustive]
+pub struct ObjectControl {}
+
+#[non_exhaustive]
+pub struct ObjectStandard {
+    attributes: ObjectAttributeStandard,
+    id: usize,
+}
+
+pub enum Mode {
+    Normal = 0,
+    Affline = 1,
+    Hidden = 2,
+    AfflineDouble = 3,
+}
+
+impl ObjectStandard {
+    pub fn commit(&self) {
+        unsafe {
+            (&mut (*OBJECT_MEMORY_STANDARD)[self.id] as *mut ObjectAttributeStandard)
+                .write_volatile(self.attributes)
+        }
     }
 
-    pub fn enable(&mut self) {}
-
-    pub fn disable(&mut self) {}
+    pub fn set_x(&mut self, x: u8) {
+        self.attributes.set_x(x)
+    }
+    pub fn set_y(&mut self, y: u8) {
+        self.attributes.set_y(y)
+    }
+    pub fn set_tile_id(&mut self, id: u32) {
+        self.attributes.set_tile_id(id)
+    }
+    pub fn set_hflip(&mut self, hflip: bool) {
+        self.attributes.set_hflip(hflip)
+    }
+}
+
+#[repr(packed)]
+#[derive(Clone, Copy)]
+pub struct ObjectAttributeStandard {
+    low: u32,
+    high: u32,
+}
+
+impl ObjectAttributeStandard {
+    pub fn set_hflip(&mut self, hflip: bool) {
+        let mask = (1 << 0xC) << 16;
+        let attr = self.low;
+        let attr = attr & !mask;
+        if hflip {
+            self.low = attr | mask
+        } else {
+            self.low = attr
+        }
+    }
+
+    pub fn set_x(&mut self, x: u8) {
+        let mask = ((1 << 8) - 1) << 16;
+        let attr1 = self.low;
+        let attr_without_x = attr1 & !mask;
+        let attr_with_new_x = attr_without_x | ((x as u32) << 16);
+        self.low = attr_with_new_x;
+    }
+
+    pub fn set_y(&mut self, y: u8) {
+        let mask = (1 << 8) - 1;
+        let attr0 = self.low;
+        let attr_without_y = attr0 & !mask;
+        let attr_with_new_y = attr_without_y | y as u32;
+        self.low = attr_with_new_y;
+    }
+
+    pub fn set_tile_id(&mut self, id: u32) {
+        let mask = (1 << 9) - 1;
+        assert!(id <= mask, "tile id is greater than 9 bits");
+        let attr = self.high;
+        let attr = attr & !mask;
+        let attr = attr | id;
+        self.high = attr;
+    }
+
+    pub fn set_mode(&mut self, mode: Mode) {
+        let mask = 0b11 << 0x8;
+        self.low = (self.low & !mask) | ((mode as u32) << 0x8);
+    }
+}
+
+impl ObjectAttributeStandard {
+    fn new() -> Self {
+        ObjectAttributeStandard { low: 0, high: 0 }
+    }
+}
+
+impl ObjectControl {
+    pub(crate) fn new() -> Self {
+        ObjectControl {}
+    }
+
+    /// # Safety
+    /// Temporary
+    pub unsafe fn clear_objects(&mut self) {
+        let mut o = ObjectAttributeStandard::new();
+        o.set_mode(Mode::Hidden);
+        for index in 0..(*OBJECT_MEMORY_STANDARD).len() {
+            (&mut (*OBJECT_MEMORY_STANDARD)[index] as *mut ObjectAttributeStandard)
+                .write_volatile(o);
+        }
+    }
+
+    pub fn enable(&mut self) {
+        let disp = DISPLAY_CONTROL.get();
+        let disp = disp | (1 << 0x0C);
+        DISPLAY_CONTROL.set(disp);
+    }
+
+    pub fn disable(&mut self) {
+        let disp = DISPLAY_CONTROL.get();
+        let disp = disp & !(1 << 0x0C);
+        DISPLAY_CONTROL.set(disp);
+    }
+
+    pub fn get_object(&self, id: usize) -> ObjectStandard {
+        assert!(id < 128, "object id must be less than 128");
+        ObjectStandard {
+            attributes: ObjectAttributeStandard::new(),
+            id,
+        }
+    }
 }

src/display/tiled0.rs

@@ -3,7 +3,7 @@ use core::convert::TryInto;
 use crate::memory_mapped::MemoryMapped1DArray;
 
 use super::{
-    object::Object, set_graphics_mode, set_graphics_settings, DisplayMode, GraphicsSettings,
+    object::ObjectControl, set_graphics_mode, set_graphics_settings, DisplayMode, GraphicsSettings,
     DISPLAY_CONTROL,
 };
 
@@ -102,7 +102,7 @@ pub struct Tiled0 {
     pub background_1: Background,
     pub background_2: Background,
     pub background_3: Background,
-    pub object: Object,
+    pub object: ObjectControl,
 }
 
 impl Tiled0 {
@@ -114,7 +114,7 @@ impl Tiled0 {
             background_1: Background { layer: 1 },
             background_2: Background { layer: 2 },
             background_3: Background { layer: 3 },
-            object: Object::new(),
+            object: ObjectControl::new(),
         }
     }