Rust game engine Piston触りかけ

Pistonはイイぞと聞いたので、少し触って見た。cargoによるビルドがとてもおされ。

extern crate piston_window;
use piston_window::*;

pub struct WinSize{pub width:u32,pub height:u32,}
pub struct CubeSize{pub width:f64,pub height:f64,}
pub struct Cube{pub x:f64,pub y:f64,}

fn main(){
    const BLUE:[f32;4]=[0.0,0.5,0.8,0.7];
    const GRAY:[f32;4]=[0.15,0.15,0.15,1.0];

    let init_window_size=WinSize{width:640,height:640};
    let cube_size=CubeSize{width:90.0,height:90.0};

    let mut cube_ptr=Cube{x:0.0,y:0.0};
    let mut cube_ptr1=Cube{x:(init_window_size.width as f64) - cube_size.width,y:0.0};

    let mut window:PistonWindow=WindowSettings::new("Test Window",[init_window_size.width,init_window_size.height])
        .exit_on_esc(true)
        .build()
        .unwrap_or_else(|e|{panic!("Failed :{}",e)});

    let window_size:Size=window.size();
    let mut arrive:bool=true;
    let mut arrive1:bool=true;

    while let Some(e)=window.next(){
        window.draw_2d(&e, |c,g|{
            clear(GRAY,g);
            rectangle(BLUE,[cube_ptr.x,cube_ptr.y,cube_size.width,cube_size.height],c.transform,g);
            if arrive && (cube_ptr.x != (window_size.width as f64) - cube_size.width || cube_ptr.y != (window_size.height as f64) - cube_size.height) {
                cube_ptr.x+=1.0;
                cube_ptr.y+=1.0;
                if cube_ptr.x == (window_size.width as f64) - cube_size.width || cube_ptr.y == (window_size.height as f64) - cube_size.height {
                    arrive=false;
                }
            }else{
                cube_ptr.x-=1.0;
                cube_ptr.y-=1.0;
                if cube_ptr.x == 0.0 || cube_ptr.y == 0.0 {
                    arrive=true;
                }
            }
        });

        window.draw_2d(&e, |c,g|{
            rectangle(BLUE,[cube_ptr1.x,cube_ptr1.y,cube_size.width,cube_size.height],c.transform,g);
            if arrive1 && (cube_ptr1.x != 0.0 || cube_ptr1.y != (window_size.height as f64) - cube_size.height) {
                cube_ptr1.x-=1.0;
                cube_ptr1.y+=1.0;
                if cube_ptr1.x == 0.0 || cube_ptr.y == (window_size.height as f64) - cube_size.height {
                    arrive1=false;
                }
            }else{
                cube_ptr1.x+=1.0;
                cube_ptr1.y-=1.0;
                if cube_ptr1.x == (window_size.width as f64) - cube_size.width || cube_ptr1.y == 0.0 {
                    arrive1=true;
                }
            }
        });
    }
}

何か久しぶりにPistonを使ってゲームでも作るのも良いかもしれない。asm.jsを使ってブラウザで動かしたりもできる様子。とてもオサレ。