Use trait for boll variants

[kaka/rust-sdl-test.git] / src / boll.rs

use sdl2::pixels::Color;
use sdl2::rect::Point;
use sdl2::rect::Rect;
use sdl2::render::Canvas;
use sdl2::video::Window;

use {SCREEN_HEIGHT, SCREEN_WIDTH};
use common::Point2D;

pub trait Boll {
    fn update(&mut self);
    fn draw(&mut self, canvas: &mut Canvas<Window>, size: u32);
}

pub struct SquareBoll {
    pub pos: Point2D<f64>,
    pub vel: Point2D<f64>,
}

impl Boll for SquareBoll {
    fn update(&mut self) {
        self.vel.y += 0.1;
        self.pos += self.vel;

        if self.pos.x < 0.0 {
            self.pos.x = -self.pos.x;
            self.vel.x = -self.vel.x;
        }
        if self.pos.x > SCREEN_WIDTH as f64 {
            self.pos.x = SCREEN_WIDTH as f64 - (self.pos.x - SCREEN_WIDTH as f64);
            self.vel.x = -self.vel.x;
        }
        if self.pos.y < 0.0 {
            self.pos.y = -self.pos.y;
            self.vel.y = -self.vel.y;
        }
        if self.pos.y > SCREEN_HEIGHT as f64 {
            self.pos.y = SCREEN_HEIGHT as f64 - (self.pos.y - SCREEN_HEIGHT as f64);
            self.vel.y = -self.vel.y;
        }
    }

    fn draw(&mut self, canvas: &mut Canvas<Window>, size: u32) {
        canvas.set_draw_color(Color::RGBA(
            255 - std::cmp::min(255, (self.vel.length() * 25.0) as u8),
            (255.0 * (self.pos.x / SCREEN_WIDTH as f64)) as u8,
            (255.0 * (self.pos.y / SCREEN_HEIGHT as f64)) as u8, 128
        ));
        let mut r = Rect::new(0, 0, size, size);
        r.center_on(Point::new(self.pos.x as i32, self.pos.y as i32));
        canvas.fill_rect(r).unwrap();
    }
}