Date: Sat, 28 Mar 1998 10:39:26 -0800 (PST)
Message-Id: <199803281839.KAA16475@adit.ap.net>
Mime-Version: 1.0
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To: * benz <benz AT primary DOT net>, djgpp AT delorie DOT com
From: Nate Eldredge <eldredge AT ap DOT net>
Subject: Re: Allegro and 16-bit color
Precedence: bulk

At 02:17  3/26/1998 -0600, * benz wrote:
>I have been trying for some time now to get Allegro to work in 16-bit
>color mode.  For some reason it never works...  What I am trying to do
>is to load some 256 color pictures (with differenet palettes) and then
>display them on a 16-bit screen.  I get no errors or warnings when I
>compile, but when I run the exe I either get a solid color filling the
>screen or a SIGSEGV error.  When I symify the SIGSEGV error, it says the
>problem is in the blit (_blit+1025 to be exact) function.  My exact
>source is below and I would really appreciate some help on what I might
>be doing wrong -- I just can't figure it out :(
>
>
>/*                    Source                    */
>#include <allegro.h>
>
>main()
>{
>   BITMAP *bmp1;
>   BITMAP *bmp2;
>   PALETTE pal1;
>   PALETTE pal2;
>
>   allegro_init();
>   set_gfx_mode(GFX_AUTODETECT, 640, 480, 0, 0);
>   set_color_depth(16);
>
>   set_color_conversion(COLORCONV_NONE);
>   bmp1 = load_bitmap("heroPc1.bmp", pal1);
>   bmp2 = load_bitmap("test1.bmp", pal2);

Check to make sure these calls succeed. Should they fail, they'll return
NULL, which will crash in `blit'. Also make sure the bitmaps really are as
large as the size you blit.

>
>   set_palette(pal1);
>   blit(bmp1, screen, 0, 0, 0, 0, 99, 99);
>   set_palette(pal2);
>   blit(bmp2, screen, 0, 0, 0, 125, 399, 187);
>
>   readkey();
>   destroy_bitmap(bmp1);
>   destroy_bitmap(bmp2);
>   set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
>}

Nate Eldredge
eldredge AT ap DOT net