Hi Andreas,

Am 23.04.2012 09:53, schrieb Andreas Lund:
> Hi,
> Running Strawberry Perl on Win 7 x64 I have installed SDL and Alien::SDL from
> CPAN (selecting option 1) and I'm writing a twin stick shooter game for fun. I
> have three questions:
> 1) When rotating sprites using the ->rotation() method the sprites often get a
> line of "artifact noise" along one of the sides, usually the right and/or
> bottom edge of the original sprite. The effect is not constant and the
> original sprites are all 100% transparent at the edges so I believe the
> artifacts are introduced by the rotation algorithm. Or is it?
Do you have a screenshot? I just can think of problems when
anti-aliasing and transparency come together...
> 2) After experimenting with different sprite sizes, it seems that there's a
> limit somewhere. When attempting to load a sprite that's too large, I get a
> seemingly valid sprite object that just doesn't seem to render anything. Is
> there a known size limit to sprites or could this be a driver issue? Or am I
> overlooking something?
See http://sdl.perl.org/SDL-GFX-Rotozoom.html, I believe width+height
must be less than 16384.
> 3) How exactly does the 'alpha_key' property work? I tried setting it to the
> ubiquitous bright purple (FF00FF) but this just caused half my sprites to
> become completely invisible. When using PNG files with an alpha channel, using
> a key color seems pointless to me, which makes the POD example code somewhat
> confusing:
>     # spawning can include almost all of the above:
>     my $sprite = SDLx::Sprite->new(
>               image   => 'hero.png',   # or surface => SDL::Surface
>               rect    => SDL::Rect,    # or x => $x, y => $y
>               clip    => SDL::Rect,
>               alpha_key => SDL::Color, # or [$r, $g, $b]
>               alpha     => 1,
>               rotation  => 45, # degrees
>          );
Ya, alpha and blitting is not the easiest things as someone might think.
If you have a png file with alpha channel, and applying an alpha color
key to it should reset the alpha channel. At least that is what I would
You cant mix the alpha channel and alpha key.
> If anyone is interested in a sneak peek, here's the code:
> http://floyd.atc.no/Programming/Perl/IfItMoves/2012-04-23.zip
Will have a look then ;o)

Cheers, FROGGS
> Suggestions are welcome :-)
> --
> Andreas Lund (fl...@atc.no)
> Tel: +47 90077162
> #include <disclaimer.h>
> "Look at you hacker, panting and sweating as you run through my corridors.
> How can you challenge a perfect immortal machine?" -- SHODAN, System Shock

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