//------------------------------------------
// Pixel
//------------------------------------------
pub trait Pixel {
  fn to_u32(&self) -> u32;
}

impl Pixel for u32 {
  fn to_u32(&self) -> u32 {
    *self
  }
}

//------------------------------------------
// Rgb
//------------------------------------------
pub struct Rgb {
  r: u8,
  g: u8,
  b: u8
}
impl Rgb {
  pub fn new(r: u8, g: u8, b: u8) -> Rgb {
    Rgb {
      r: r,
      g: g,
      b: b
    }
  }
}
impl Pixel for Rgb {
  fn to_u32(&self) -> u32 {
    ((self.r as u32) << 24) +
    ((self.g as u32) << 16) +
    ((self.b as u32) << 8)
  }
}
//------------------------------------------
// Rgba
//------------------------------------------
pub struct Rgba {
  r: u8,
  g: u8,
  b: u8,
  a: u8
}
impl Rgba {
  pub fn new(r: u8, g: u8, b: u8, a: u8) -> Rgba {
    Rgba {
      r: r,
      g: g,
      b: b,
      a: a
    }
  }
}
impl Pixel for Rgba {
  fn to_u32(&self) -> u32 {
    ((self.r as u32) << 24) +
    ((self.g as u32) << 16) +
    ((self.b as u32) << 8)  +
      self.a as u32
  }
}
//------------------------------------------
// PixelBuffer
//------------------------------------------
pub struct PixelBuffer {
  pub _width    : usize,
  pub _height   : usize,
  pub _pixels   : Vec<u32>,
  pub _depth    : Vec<f32>,
  pub _stencil  : Vec<u8>
}
impl PixelBuffer {
  pub fn new(width: usize, height: usize) -> PixelBuffer {
    PixelBuffer {
      _width    : width,
      _height   : height,
      _pixels   : vec![0_u32; width * height],
      _depth    : vec![0_f32; width * height],
      _stencil  : vec![0_u8;  width * height]
    }
  }

  pub fn width(&self) -> usize {
    self._width
  }

  pub fn height(&self) -> usize {
    self._height
  }

  pub fn clear<P: Pixel> (&mut self, p: P) {
    for i in 0..self._pixels.len() {
      self._pixels[i] = p.to_u32()
    }
  }
  pub fn set<P: Pixel>(&mut self, x: usize, y: usize, p: P) {
    self._pixels[x + self._width * y] = p.to_u32();
  }
}