[SDL] Fwd: How to retain RGBA when copying an SDL Surface

Dominique Louis Dominique at SavageSoftware.com.au
Tue Jul 23 11:25:01 PDT 2002


Thanks Joel,
   We will add that to our FAQ.


Dominique.

Joel Chen wrote:
> Double check your code that creates the new surface and 
> make sure you turn off SRCALPHA on the original. 
> ie. SDL_SetAlpha( surf, 0, 0 )
> 
> 
> 
> 
>>-----Original Message-----
>>From: Dominique Louis [mailto:Dominique at SavageSoftware.com.au] 
>>Sent: Monday, July 22, 2002 2:31 PM
>>To: sdl at libsdl.org
>>Subject: [SDL] Fwd: How to retain RGBA when copying an SDL Surface
>>
>>
>>One of the JEDI-SDL members has the following question...
>>
>>Any C code would be helpfull.
>>
>>-------- Original Message --------
>>Hi,
>>   I have an RGBA Surface created using IMG_Load (works great) NOW I 
>>create a NEW RGBA Surface using SDL_CreateRGBSurface (with all the 
>>parameters from the first Surface).
>>The problem is HOW do I copy the image WITH the A to the new created 
>>Surface ?
>>If I'll use SDL_BlitSurface I won't get the RGBA I'll get only RGB.
>>
>> >From the SDL:
>>"
>>RGBA->RGBA:
>>       SDL_SRCALPHA set:
>>    alpha-blend (using the source alpha channel) the RGB values;
>>    leave destination alpha untouched. [Note: is this correct?]
>>    SDL_SRCCOLORKEY ignored.
>>       SDL_SRCALPHA not set:
>>    copy all of RGBA to the destination.
>>    if SDL_SRCCOLORKEY set, only copy the pixels matching the
>>    RGB values of the source colour key, ignoring alpha in the
>>    comparison.
>>"
>>(so for the Note, its correct :/ )
>>
>>Please let me know,
>>Ariel.
>>
>>
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>>
>>-- 
>>
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http://www.DelphiGamer.com := for all your Object Pascal game 
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