PNG images loaded in example tutorials like glod-game do not have their alpha channels premultiplied

[Yttruire]

This results in e.g. glod game tutorial, which uses transparent PNG images to render PNG images incorrectly. See issue here. When this branch has been merged into Shards, the tutorials should be updated to premultiply the alpha channels of the PNG images loaded so that learners do not encounter this issue.

For glod-game, there are 2 ways to achieve the required fix by changing load-texture.

Method 1:

(defshards load-texture [name]
  (LoadImage name :PremultiplyAlpha true)
  (GFX.Texture))

Method 2:

(defshards load-texture [name]
  (LoadImage name) (PremultiplyAlpha)
  (GFX.Texture))

The crucial point is to add the respective parameter to LoadImage when loading PNG images, or to add the PremultiplyAlpha shard after loading the PNG image