gistfile1.rs

use std::os;

#[allow(unused_variables)]
fn main() {
  let width     = 2u8;
  let height    = 3u8;
  let size      = 4u8;

  let pitch = width * size;
  let (mut x_offset, mut y_offset) = (0u8, 0u8);

  let chunk = match os::MemoryMap::new((width * height * size) as uint, &[
    os::MapOption::MapReadable,
    os::MapOption::MapWritable
  ]) {
    Ok(chunk) => chunk,
    Err(msg) => panic!("{}", msg)
  };
  let base = chunk.ptr as *mut u32;
    for y in range(0u8, height) {
      for x in range(0u8, width) {
        let red: u8 = 0u8;
        let green: u8 = y + y_offset;
        let blue: u8 = x + x_offset;
        *base.offset_mut(y * height + width) = (green << 8) | blue;
      }
  };
}

gistfile2.c

internal void
RenderWeirdGradient(int BlueOffset, int GreenOffset)
{    
    int Width = BitmapWidth;
    int Height = BitmapHeight;

    int Pitch = Width*BytesPerPixel;
    uint8 *Row = (uint8 *)BitmapMemory;    
    for(int Y = 0;
        Y < BitmapHeight;
        ++Y)
    {
        uint32 *Pixel = (uint32 *)Row;
        for(int X = 0;
            X < BitmapWidth;
            ++X)
        {
            uint8 Blue = (X + BlueOffset);
            uint8 Green = (Y + GreenOffset);
            
            *Pixel++ = ((Green << 8) | Blue);
        }

        Row += Pitch;
    }
}