agb/template/src/main.rs

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// Games made using `agb` are no_std which means you don't have access to the standard
// rust library. This is because the game boy advance doesn't really have an operating
// system, so most of the content of the standard library doesn't apply.
//
// Provided you haven't disabled it, agb does provide an allocator, so it is possible
// to use both the `core` and the `alloc` built in crates.
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#![no_std]
// `agb` defines its own `main` function, so you must declare your game's main function
// using the #[agb::entry] proc macro. Failing to do so will cause failure in linking
// which won't be a particularly clear error message.
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#![no_main]
use agb::{display, syscall};
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// The main function must take 1 arguments and never return. The agb::entry decorator
// ensures that everything is in order. `agb` will call this after setting up the stack
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// and interrupt handlers correctly. It will also handle creating the `Gba` struct for you.
#[agb::entry]
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fn main(mut gba: agb::Gba) -> ! {
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let mut bitmap = gba.display.video.bitmap3();
for x in 0..display::WIDTH {
let y = syscall::sqrt(x << 6);
let y = (display::HEIGHT - y).clamp(0, display::HEIGHT - 1);
bitmap.draw_point(x, y, 0x001F);
}
loop {
syscall::halt();
}
}