From: gregorio AT jet DOT es (Grzegorz Adam Hankiewicz)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Extracting a pixel from an Allegro BITMAP
Date: Fri, 09 Jan 1998 12:57:38 GMT
Organization: Gogosoftware
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Message-ID: <34b61e19.6803419@news.jet.es>
References: <19980109085201 DOT DAA02949 AT ladder02 DOT news DOT aol DOT com>
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To: djgpp AT delorie DOT com
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>       a_pixel = double_buffer[(y<<8) + (y<<6) + (x>>2)];
>     - or -
>      double_buffer [(y<<8) + (y<<6) + (x>>2)] = a_pixel;
>
>   How can I do that with an Allegro BITMAP?

Try this:

a_pixel=bitmap->line[y][x];
or
bitmap->line[y][x]=a_pixel;

This only works if bitmap is a memory bitmap, not a svga screen or
something like that.

Read in the Allegro documentation the section "Direct access to video
memory" for more information about accessing the memory and bitmap
structures.

- Grzegorz Adam Hankiewicz - gregorio AT jet DOT es - http://web.jet.es/gregorio
- Gogosoftware - http://web.jet.es/gregorio/gogosoftware