[SDL] Reading and writing Data to/from Surface

[Jan Pfeifer]

it's a cool example, but it's worth mentioning that it runs with 320x320 
(we've been considering 640x480x16 bits in the discussion). 

=)

jan

btw it would be nice to make it rotate countinously (different angles require 
extra shears ...) and get some average speed ...



> The program loads an image and pseudo-rotates it using combinations of
> horizontal and vertical shears (skews). Just move your mouse around to see
> it. On small rotations (only 2 skews) I get arount 45fps on P3/933. For
> rotations up to 90degrees (5 skews) it drops down to 30fps.
> The program will work only in 32bps (see lines 109 and 118, where the
> pointers should be cast depending on the pixeldepth), because I was too
> lazy to do it properly (you should make depth switch in the beginning of
> the function and repeat the loops with different casts; you don't want to
> make switch within the loop).
> Is it faster than yours ?
> Regards,
> 	Jacek