pixels/examples/minimal-sdl2/main.rs
2019-11-19 19:58:21 -08:00

121 lines
3.3 KiB
Rust

#![deny(clippy::all)]
#![forbid(unsafe_code)]
#![cfg_attr(not(debug_assertions), windows_subsystem = "windows")]
use beryllium::*;
use pixels::{wgpu::Surface, Pixels, SurfaceTexture};
const WIDTH: u32 = 320;
const HEIGHT: u32 = 240;
const BOX_SIZE: i16 = 64;
/// Representation of the application state. In this example, a box will bounce around the screen.
struct World {
box_x: i16,
box_y: i16,
velocity_x: i16,
velocity_y: i16,
}
fn main() -> Result<(), String> {
env_logger::init();
let sdl = beryllium::init()?;
let window = sdl.create_window(
"Hello Pixels",
WINDOW_POSITION_CENTERED,
WINDOW_POSITION_CENTERED,
WIDTH as i32,
HEIGHT as i32,
WindowFlags::default(),
)?;
window.set_minimum_size(WIDTH as i32, HEIGHT as i32);
window.set_resizable(true);
let mut pixels = {
let surface = Surface::create(&window);
let surface_texture = SurfaceTexture::new(WIDTH, HEIGHT, surface);
Pixels::new(WIDTH, HEIGHT, surface_texture).map_err(|e| format!("{:?}", e))?
};
let mut world = World::new();
'game_loop: loop {
while let Some(event) = sdl.poll_event() {
match event {
// Close events
Event::Quit { .. } => break 'game_loop,
Event::Keyboard {
key_info:
KeyInfo {
keycode: Some(key), ..
},
..
} if key == Keycode::Escape => break 'game_loop,
// Resize the window
Event::WindowSizeChanged { width, height, .. } => {
pixels.resize(width as u32, height as u32)
}
_ => (),
}
}
// Update internal state
world.update();
// Draw the current frame
world.draw(pixels.get_frame());
pixels.render();
}
Ok(())
}
impl World {
/// Create a new `World` instance that can draw a moving box.
fn new() -> Self {
Self {
box_x: 24,
box_y: 16,
velocity_x: 1,
velocity_y: 1,
}
}
/// Update the `World` internal state; bounce the box around the screen.
fn update(&mut self) {
if self.box_x <= 0 || self.box_x + BOX_SIZE - 1 >= WIDTH as i16 {
self.velocity_x *= -1;
}
if self.box_y <= 0 || self.box_y + BOX_SIZE - 1 >= HEIGHT as i16 {
self.velocity_y *= -1;
}
self.box_x += self.velocity_x;
self.box_y += self.velocity_y;
}
/// Draw the `World` state to the frame buffer.
///
/// Assumes the default texture format: [`wgpu::TextureFormat::Rgba8UnormSrgb`]
fn draw(&self, frame: &mut [u8]) {
for (i, pixel) in frame.chunks_exact_mut(4).enumerate() {
let x = (i % WIDTH as usize) as i16;
let y = (i / WIDTH as usize) as i16;
let inside_the_box = x >= self.box_x
&& x < self.box_x + BOX_SIZE
&& y >= self.box_y
&& y < self.box_y + BOX_SIZE;
let rgba = if inside_the_box {
[0x5e, 0x48, 0xe8, 0xff]
} else {
[0x48, 0xb2, 0xe8, 0xff]
};
pixel.copy_from_slice(&rgba);
}
}
}