Re: SDL surface blit & flip

On Fri, 2010-10-01 at 17:42 +0200, Rouven Raudzus wrote: 
> Hello,

Hello Rouven,

> some time ago i contacted you for some perl sdl talk. atm i got some
> time to get into sdl, i'm getting forward tho.

Cool. Have a look at the SDL_Manual we are working on.
http://sdlperl.ath.cx/releases/SDL_Manual.pdf

We have several additions to SDLx::* now that make using SDL easier.

> now i got some question. how do i most effectively blit stuff on screen?
> 
> blitting a 320x240 px part out of a 1024x768 px image to the dest
> surface with 40 fps tooks like 40% cpu on an atom 1,6ghz. isnt that too
> much?

If you have an SDLx::App or SDLx::Surface you can do
SDLx::Surface->blit(SDLx::Surface, [x,y,w,h]);

> 
> first i create the screen surface with SDL::Video::set_video_mode, then
> i load the image with SDL::Image::load and put 320x240 px of it to
> screen surface with blit_surface. then i update screen with
> SDL::Video::flip. how to make it more cpu effective?
> 
SDLx::App->new( w=> 320, h=> 240) # will make the screen.
my $image = SDLx::Surface->new( image => "Image.bmp" ); #will do the
image
then $image->blit( $app );

Also using flags => SDL_HWSURFACE | SDL_DOUBLEBUF  in
SDLx::App->new( ...) will make flip() faster then update(). Also
surfaces that have a size of 2^n are best for blitting. Finally using 
8bpp PNG index for images are the fastest.


> i'm working on a package to create graphical menus, popups, etc in perl
> sdl using xml files to define them. may i help perl-sdl development by
> creating modules?

Absolutely! Have a look at Allegro too. It has GUI using SDL and it has
a perl module (although it might be old now).

> with friendly regards,
> rouven raudzus

Kartik Thakore 

-- 
Kartik Thakore <[email protected]>