add an example using the keypad.

examples/keypad.rs

@@ -0,0 +1,74 @@
+#![no_std]
+#![no_main]
+
+use gba::prelude::*;
+
+#[panic_handler]
+#[allow(unused)]
+fn panic(info: &core::panic::PanicInfo) -> ! {
+  loop {
+    DISPCNT.read();
+  }
+}
+
+/// Performs a busy loop until VBlank starts.
+///
+/// This is very inefficient, and please keep following the lessons until we
+/// cover how interrupts work!
+pub fn spin_until_vblank() {
+  while VCOUNT.read() < 160 {}
+}
+
+/// Performs a busy loop until VDraw starts.
+///
+/// This is very inefficient, and please keep following the lessons until we
+/// cover how interrupts work!
+pub fn spin_until_vdraw() {
+  while VCOUNT.read() >= 160 {}
+}
+
+#[no_mangle]
+pub fn main() -> ! {
+  const SETTING: DisplayControl = DisplayControl::new().with_display_mode(3).with_display_bg2(true);
+  DISPCNT.write(SETTING);
+
+  const RED: Color = Color::from_rgb(31, 0, 0);
+  const GREEN: Color = Color::from_rgb(0, 31, 0);
+
+  let mut keys = Keys::new();
+
+  fn draw_square(x: usize, y: usize, color: Color) {
+    mode3::bitmap_xy(x, y).write(color);
+    mode3::bitmap_xy(x, y + 1).write(color);
+    mode3::bitmap_xy(x, y + 2).write(color);
+    mode3::bitmap_xy(x + 1, y).write(color);
+    mode3::bitmap_xy(x + 1, y + 1).write(color);
+    mode3::bitmap_xy(x + 1, y + 2).write(color);
+    mode3::bitmap_xy(x + 2, y).write(color);
+    mode3::bitmap_xy(x + 2, y + 1).write(color);
+    mode3::bitmap_xy(x + 2, y + 2).write(color);
+  }
+
+  loop {
+    // wait until we're into the vblank period
+    spin_until_vdraw();
+    spin_until_vblank();
+
+    draw_square(1, 1, if keys.l() { GREEN } else { RED });
+    draw_square(mode3::WIDTH - 4, 1, if keys.r() { GREEN } else { RED });
+    //
+    draw_square(mode3::WIDTH - 4, mode3::HEIGHT / 2, if keys.a() { GREEN } else { RED });
+    draw_square(mode3::WIDTH - 4 - 20, mode3::HEIGHT / 2 + 20, if keys.b() { GREEN } else { RED });
+    //
+    draw_square(mode3::WIDTH / 2 + 10, mode3::HEIGHT - 5, if keys.start() { GREEN } else { RED });
+    draw_square(mode3::WIDTH / 2 - 10, mode3::HEIGHT - 5, if keys.select() { GREEN } else { RED });
+    //
+    draw_square(30, mode3::HEIGHT / 2 - 20, if keys.up() { GREEN } else { RED });
+    draw_square(30, mode3::HEIGHT / 2 + 20, if keys.down() { GREEN } else { RED });
+    draw_square(10, mode3::HEIGHT / 2, if keys.left() { GREEN } else { RED });
+    draw_square(50, mode3::HEIGHT / 2, if keys.right() { GREEN } else { RED });
+
+    // read our keys for next frame
+    keys = KEYINPUT.read().into();
+  }
+}