From: Shawn Hargreaves <Shawn AT talula DOT demon DOT co DOT uk>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Any Allegro users want to help?
Date: Mon, 30 Dec 1996 19:49:14 +0000
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Message-ID: <l$B64vA6yByyEw3a@talula.demon.co.uk>
References: <01bbf45d$777df560$932449c2 AT default>
NNTP-Posting-Host: talula.demon.co.uk
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To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

>Anyway, is there anyone who is feeling charitable enough to help me with a
>few Allegro basics? All I want to do is initiate a graphics mode (basic VGA
>will do, but I'd prefer to have the option), write filled triangles to a
>virtual RAM buffer, and copy this buffer to the video ram. Just a few

Try this. Compile with something along the lines of:
        gcc foobar.c -o foobar.exe -lalleg

---- cut here, foobar.c ----

#include "allegro.h"

int main()
{
   /* current object position */
   int x = 100, y = 100;

   /* an offscreen buffer for drawing the image */
   BITMAP *buffer;

   /* initialise Allegro and select a 640x480 video mode */
   allegro_init(); 
   install_keyboard(); 
   set_gfx_mode(GFX_AUTODETECT, 640, 480, 0, 0);
   set_palette(desktop_palette);

   /* create the offscreen buffer */
   buffer = create_bitmap(SCREEN_W, SCREEN_H);

   /* repeat until ESC is pressed */
   while (!key[KEY_ESC]) {
      /* clear the offscreen buffer */
      clear(buffer);

      /* draw a triangle onto it */
      triangle(buffer, x, y, x+20, y, x, y+20, 255);

      /* synchronise with retrace, then copy buffer to the screen */
      vsync();
      blit(buffer, screen, 0, 0, 0, 0, SCREEN_W, SCREEN_H);

      /* use arrow keys to move the triangle around */
      if (key[KEY_LEFT])
         x--;

      if (key[KEY_RIGHT])
         x++;

      if (key[KEY_UP])
         y--;

      if (key[KEY_DOWN])
         y++;
   } 

   /* shutdown and free the buffer memory */
   destroy_bitmap(buffer);
   allegro_exit();

   return 0;
}

---- end of foobar.c ----

Hope that helps...

/*
 *  Shawn Hargreaves - shawn AT talula DOT demon DOT co DOT uk - http://www.talula.demon.co.uk/
 *  Ghoti: 'gh' as in 'enough', 'o' as in 'women', and 'ti' as in 'nation'.
 */