Re: A89: Run Down on some Things


[Prev][Next][Index][Thread]

Re: A89: Run Down on some Things




In a message dated 12/12/1998 10:10:58 PM Pacific Standard Time,
senoramor@yahoo.com writes:

> Ok.  I now understand that.  Thank you.  My next question is why do we
>  have masks?  Is there a special function they serve (remember I'm new
>  at this...)?

One of the sprite functions uses a mask to draw certain pixels in an image,
while not drawing the rest.  This is used because sprites are rectangular.
For example, if there was an image of an unfilled circle, you could use a mask
to draw the circle and the whitespace inside it, but not the rest of the
sprite which is not the circle.  If you had a filled square and you drew the
circle on the square like this, you would see a white circle in middle of the
square, but the rest of the square would still be there.

Daniel Imfeld