Coordinates to Picture

coordToPicture takes a “Snake coordinate” and makes a squarePicture for it. We need to do some conversion here because the coordinate system of Gloss and the coordinates for the Snake game are not the same.

In the Gloss coordinate system (0,0) is the center of the screen. In the Snake coordinate system (0,0) represent the upper left square.

Translating the coordinate (0,0) should result in moving to position (-315,315) and then drawing a square. Below you see an example of the function in action, note that Polygon here is created by squarePicture.

*Main> coordToPicture (0,0)
Translate (-315.0) 315.0 (Polygon [(-4.0,-4.0),(-4.0,4.0),(4.0,4.0),(4.0,-4.0)])

Read more about the gloss library here: http://hackage.haskell.org/package/gloss

HINTS:

• make use of the functions translate,fromIntegral and squarePicture
• make use of the constants snake_scale, width and height