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