finish up chicken demo

This commit is contained in:
Corwin Kuiper 2021-03-12 14:55:44 +00:00 committed by Corwin
parent bea753d81a
commit fbdb91e9e0

View file

@ -5,9 +5,17 @@ extern crate gba;
use core::convert::{Into, TryInto};
use gba::{
display::{object::ObjectStandard, tiled0, HEIGHT, WIDTH},
input::Button,
number::Num,
};
#[derive(PartialEq, Eq)]
enum State {
Ground,
Upwards,
Flapping,
}
struct Character {
object: ObjectStandard,
position: Vector2D,
@ -19,12 +27,23 @@ struct Vector2D {
y: i32,
}
fn tile_is_collidable(tile: u16) -> bool {
let masked = tile & 0b0000001111111111;
masked == 0 || masked == 4
}
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 map_as_grid: &[[u16; 32]; 32] = unsafe {
(&MAP_MAP as *const [u16; 1024] as *const [[u16; 32]; 32])
.as_ref()
.unwrap()
};
let mut gba = gba::Gba::new();
let mut gfx = gba.display.video.tiled0();
let vblank = gba.display.vblank.get();
@ -54,8 +73,8 @@ fn main(_argc: isize, _argv: *const *const u8) -> isize {
let mut chicken = Character {
object: unsafe { object.get_object(0) },
position: Vector2D {
x: 20 << 8,
y: 20 << 8,
x: (6 * 8) << 8,
y: ((7 * 8) - 4) << 8,
},
velocity: Vector2D { x: 0, y: 0 },
};
@ -69,9 +88,14 @@ fn main(_argc: isize, _argv: *const *const u8) -> isize {
.set_y((chicken.position.y >> 8).try_into().unwrap());
chicken.object.commit();
let acceleration = 1 << 8;
let acceleration = 1 << 4;
let gravity = 1 << 4;
let flapping_gravity = gravity / 3;
let jump_velocity = 1 << 9;
let mut frame_count = 0;
let terminal_velocity = (1 << 8) / 2;
loop {
vblank.wait_for_VBlank();
frame_count += 1;
@ -80,45 +104,133 @@ fn main(_argc: isize, _argv: *const *const u8) -> isize {
// Horizontal movement
chicken.velocity.x += (input.x_tri() as i32) * acceleration;
chicken.velocity.x = 10 * chicken.velocity.x / 16;
chicken.velocity.x = 61 * chicken.velocity.x / 64;
// Update position based on velocity
chicken.position.x += chicken.velocity.x;
chicken.position.y += chicken.velocity.y;
// Update position based on collision detection
let state = handle_collision(
&mut chicken,
map_as_grid,
gravity,
flapping_gravity,
terminal_velocity,
);
// 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);
// Jumping code
if state == State::Ground && input.is_just_pressed(Button::A) {
chicken.velocity.y = -jump_velocity;
}
// 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());
restrict_to_screen(&mut chicken);
update_chicken_object(&mut chicken, state, frame_count);
// Commit the chicken to vram
chicken.object.commit();
}
}
fn update_chicken_object(chicken: &mut Character, state: State, frame_count: u32) {
if chicken.velocity.x > 1 {
chicken.object.set_hflip(false);
} else if chicken.velocity.x < -1 {
chicken.object.set_hflip(true);
}
match (state) {
State::Ground => {
if chicken.velocity.x.abs() > 1 << 4 {
chicken
.object
.set_tile_id(frame_ranger(frame_count, 1, 3, 10));
} else {
chicken.object.set_tile_id(0);
}
}
State::Upwards => {}
State::Flapping => {
chicken
.object
.set_tile_id(frame_ranger(frame_count, 4, 5, 5));
}
}
let x: u8 = (chicken.position.x >> 8).try_into().unwrap();
let y: u8 = (chicken.position.y >> 8).try_into().unwrap();
chicken.object.set_x(x - 4);
chicken.object.set_y(y - 4);
}
fn restrict_to_screen(chicken: &mut Character) {
if chicken.position.x > (WIDTH - 8 + 4) << 8 {
chicken.velocity.x = 0;
chicken.position.x = (WIDTH - 8 + 4) << 8;
} else if chicken.position.x < 4 << 8 {
chicken.velocity.x = 0;
chicken.position.x = 4 << 8;
}
if chicken.position.y > (HEIGHT - 8 + 4) << 8 {
chicken.velocity.y = 0;
chicken.position.y = (HEIGHT - 8 + 4) << 8;
} else if chicken.position.y < 4 << 8 {
chicken.velocity.y = 0;
chicken.position.y = 4 << 8;
}
}
fn handle_collision(
chicken: &mut Character,
map_as_grid: &[[u16; 32]; 32],
gravity: i32,
flapping_gravity: i32,
terminal_velocity: i32,
) -> State {
let mut new_chicken_x = chicken.position.x + chicken.velocity.x;
let mut new_chicken_y = chicken.position.y + chicken.velocity.y;
let tile_x = ((new_chicken_x >> 8) / 8) as usize;
let tile_y = ((new_chicken_y >> 8) / 8) as usize;
let left = (((new_chicken_x >> 8) - 4) / 8) as usize;
let right = (((new_chicken_x >> 8) + 4) / 8) as usize;
let top = (((new_chicken_y >> 8) - 4) / 8) as usize;
let bottom = (((new_chicken_y >> 8) + 4) / 8) as usize;
if chicken.velocity.x < 0 && tile_is_collidable(map_as_grid[tile_y][left]) {
new_chicken_x = (((left + 1) * 8 + 4) << 8) as i32;
chicken.velocity.x = 0;
} else if chicken.velocity.x > 0 && tile_is_collidable(map_as_grid[tile_y][right]) {
new_chicken_x = ((right * 8 - 4) << 8) as i32;
chicken.velocity.x = 0;
}
if chicken.velocity.y < 0 && tile_is_collidable(map_as_grid[top][tile_x]) {
new_chicken_y = ((((top + 1) * 8 + 4) << 8) + 4) as i32;
chicken.velocity.y = 0;
} else if chicken.velocity.y > 0 && tile_is_collidable(map_as_grid[bottom][tile_x]) {
new_chicken_y = ((bottom * 8 - 4) << 8) as i32;
chicken.velocity.y = 0;
}
let mut air_animation = State::Ground;
if !tile_is_collidable(map_as_grid[bottom][tile_x]) {
if chicken.velocity.y < 0 {
air_animation = State::Upwards;
chicken.velocity.y += gravity;
} else {
air_animation = State::Flapping;
chicken.velocity.y += flapping_gravity;
if chicken.velocity.y > terminal_velocity {
chicken.velocity.y = terminal_velocity;
}
}
}
chicken.position.x = new_chicken_x;
chicken.position.y = new_chicken_y;
air_animation
}
// Below is the data for the sprites
static CHICKEN_TILES: [u32; 8 * 6] = [