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75 lines
2.8 KiB
Rust
75 lines
2.8 KiB
Rust
// Games made using `agb` are no_std which means you don't have access to the standard
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// rust library. This is because the game boy advance doesn't really have an operating
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// system, so most of the content of the standard library doesn't apply.
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//
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// Provided you haven't disabled it, agb does provide an allocator, so it is possible
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// to use both the `core` and the `alloc` built in crates.
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#![no_std]
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// `agb` defines its own `main` function, so you must declare your game's main function
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// using the #[agb::entry] proc macro. Failing to do so will cause failure in linking
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// which won't be a particularly clear error message.
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#![no_main]
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use agb::{
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display::object::{Graphics, Tag},
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include_aseprite,
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};
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// Import the sprites in to this constant. This holds the sprite
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// and palette data in a way that is manageable by agb.
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const GRAPHICS: &Graphics = include_aseprite!("gfx/sprites.aseprite");
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// We define some easy ways of referencing the sprites
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#[allow(dead_code)]
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const PADDLE_END: &Tag = GRAPHICS.tags().get("Paddle End");
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#[allow(dead_code)]
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const PADDLE_MID: &Tag = GRAPHICS.tags().get("Paddle Mid");
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const BALL: &Tag = GRAPHICS.tags().get("Ball");
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// The main function must take 0 arguments and never return. The agb::entry decorator
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// ensures that everything is in order. `agb` will call this after setting up the stack
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// and interrupt handlers correctly.
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#[agb::entry]
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fn main(mut gba: agb::Gba) -> ! {
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// Get the OAM manager
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let object = gba.display.object.get();
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// Create an object with the ball sprite
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let mut ball = object.object_sprite(BALL.sprite(0));
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// Place this at some point on the screen, (50, 50) for example
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ball.set_x(50).set_y(50).show();
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// Now commit the object controller so this change is reflected on the screen,
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// this should normally be done in vblank but it'll work just fine here for now
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object.commit();
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let mut ball_x = 50;
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let mut ball_y = 50;
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let mut x_velocity = 1;
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let mut y_velocity = 1;
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loop {
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// This will calculate the new position and enforce the position
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// of the ball remains within the screen
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ball_x = (ball_x + x_velocity).clamp(0, agb::display::WIDTH - 16);
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ball_y = (ball_y + y_velocity).clamp(0, agb::display::HEIGHT - 16);
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// We check if the ball reaches the edge of the screen and reverse it's direction
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if ball_x == 0 || ball_x == agb::display::WIDTH - 16 {
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x_velocity = -x_velocity;
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}
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if ball_y == 0 || ball_y == agb::display::HEIGHT - 16 {
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y_velocity = -y_velocity;
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}
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// Set the position of the ball to match our new calculated position
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ball.set_x(ball_x as u16).set_y(ball_y as u16);
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// Wait for vblank, then commit the objects to the screen
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agb::display::busy_wait_for_vblank();
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object.commit();
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}
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}
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