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 expect. 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
