🚀 go-pugleaf

In article <1992Aug26.152939.4449@uxa.ecn.bgu.edu>, mucds@uxa.ecn.bgu.edu (Corey D. Stinson) writes:
|> 	Could someone help me with a problem.  I have a small sprite
|> (bitmapped) and when animating, instead of re-drawing the picture over
|> and over to repesent the rotation stages I would like to develop some
|> algorithm to rotate the image.

Rotating the bitmap is easy. Apply a 2x2 rotational transformation
of sin/cos the angle you want to rotate by.

|> And suggestions on one that would not degrade the image

That's the tough part. The rotation is gives you floating point
results (between) pixels. When you integerize, it'll get a little
blocky. If you're really keen on getting good results you'll have
to clean it up (esp. the edges). Convolve the image with a Laplacian
mask (3x3 would be (0,1,0),(1,-5,1),(0,1,0)) to smooth it.
These are simple to apply, and give reasonable results.

Bryan