[SDL] Best way to rotate a sprite?

Daniel Phillips phillips at arcor.de
Tue Jan 28 17:34:01 PST 2003

On Tuesday 28 January 2003 23:30, Sami Näätänen wrote:
> On Tuesday 28 January 2003 22:54, Sami Näätänen wrote:
> In fact the above thing doesn't work correctly, because the C standard
> defines the %-operator as mathematically correct reminder operation.
> So the  -1 % 32 = -1, but we want it to be 31.

Niggle time:

You meant to say the C standard defines the % operator as the mathematically
*incorrect* remainder, otherwise known as truncation towards zero, and 
formally defined as discarding any fractional part of the result.  This is 
purely for efficiency - mathematically it's offensive, but unfortunately we 
can't go back in time and add the few extra transistors it would have taken 
to do the job properly in the early CPUs.



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