vanrijn/src/main.rs

111 lines
3.0 KiB
Rust

use sdl2::event::Event;
use sdl2::keyboard::Keycode;
use sdl2::pixels::PixelFormatEnum;
use sdl2::render::{Canvas, Texture};
use sdl2::Sdl;
use std::time::Duration;
struct OutputImage {
pixel_data: Vec<u8>,
width: u32,
height: u32,
channels: u32,
}
impl OutputImage {
fn new(width: u32, height: u32) -> OutputImage {
OutputImage {
width: width,
height: height,
channels: 3,
pixel_data: vec![0; (width * height * 3) as usize],
}
}
fn clear(&mut self) -> &mut OutputImage {
for byte in self.pixel_data.iter_mut() {
*byte = 0u8;
}
self
}
fn set_color(&mut self, row: u32, column: u32, red: u8, green: u8, blue: u8) {
assert!(row < self.height && column < self.width);
let index = ((row * self.width + column) * self.channels) as usize;
self.pixel_data[index] = red;
self.pixel_data[index + 1] = green;
self.pixel_data[index + 2] = blue;
}
fn update_texture(&self, texture: &mut Texture) {
texture
.update(
None,
self.pixel_data.as_slice(),
(self.width * self.channels) as usize,
)
.expect("Couldn't update texture.");
}
}
fn init_canvas(
image_width: u32,
image_height: u32,
) -> Result<(Sdl, Canvas<sdl2::video::Window>), Box<dyn std::error::Error>> {
let sdl_context = sdl2::init()?;
let video_subsystem = sdl_context.video()?;
let window = video_subsystem
.window("van Rijn", image_width as u32, image_height as u32)
.position_centered()
.build()?;
let canvas = window.into_canvas().build().unwrap();
Ok((sdl_context, canvas))
}
pub fn main() -> Result<(), Box<dyn std::error::Error>> {
let image_width = 1200;
let image_height = 900;
let (sdl_context, mut canvas) = init_canvas(image_width, image_height)?;
let texture_creator = canvas.texture_creator();
let mut rendered_image_texture = texture_creator.create_texture_streaming(
PixelFormatEnum::RGB24,
image_width as u32,
image_height as u32,
)?;
let mut output_image = OutputImage::new(image_width, image_height);
output_image.clear();
let mut event_pump = sdl_context.event_pump()?;
let mut i = 0;
'running: loop {
i = (i + 1) % 255;
for event in event_pump.poll_iter() {
match event {
Event::Quit { .. }
| Event::KeyDown {
keycode: Some(Keycode::Escape),
..
} => break 'running,
_ => {}
}
}
output_image.update_texture(&mut rendered_image_texture);
for row in 0..image_height {
for column in 0..image_width {
output_image.set_color(row, column, i, i, i);
}
}
canvas.copy(&rendered_image_texture, None, None)?;
canvas.present();
::std::thread::sleep(Duration::new(0, 1_000_000_000u32 / 60));
}
Ok(())
}