What about just scaling the base color bitmap on screen, and apply a detail-bitmap on it with the shader? Just a black tga with transparent parts that form the details on the (plain colored) block.

Currently playing too much with the noise-landscape generator .

Edit: I went for the cheap approach: put up a window element in a panel, apply one detail-tile tga bitmap to it, and resize the window to full screen. The detailed tile is automatically tiled over the screen. Insta-tiles. This also makes cubes from the sky though, not sure if I like that. Will try the shader approach too soon. Thanks for the shader snippet and all suggestions .