[SDL] SDL_LowerBlit

[walisser at mac.com]

On Sunday, June 9, 2002, at 07:57  AM, Niklas Pettersson wrote:

> What precausions must I take to use lowerblit?
>
> 1) regarding clipping?
> 2) regarding locked surfaces?
> ...
> ..
> n) ...

If you really want to know all the details, look at the code:

http://www.libsdl.org/cgi/cvsweb.cgi/SDL12/src/video/SDL_surface.c?rev=1.8&
content-type=text/x-cvsweb-markup

>
> All info is appreciated. Hm, maybe SDL should offer some way to bypass 
> clipping in a "nicer" way?

I can't think of a nicer way, aside from SDL_NO_CLIP passed to 
SDL_SetVideoMode(). Clipping is done by default because all of the 
blitting routines (for all the different pixel formats, and perhaps 
hardware blits) assume they have sane values, and don't check them out. 
This is why you're really screwed if you pass bad values to 
SDL_LowerBlit().