Replaces every pixel with a part of the texture set by
The texture used must be power of 2 and must also be 8 times higher than it is wide (an aspect ratio of 1:8) in order to function.
The shader replaces every pixel with a part of the texture depending on its brightness. Dark areas will use the upper parts of the texture and brighter parts the lower parts of the texture.
The size of the texturing on the x axis
The size of the texturing on the y axis