From: aho450s AT nic DOT smsu DOT edu (Tony O'Bryan)
Newsgroups: comp.os.msdos.djgpp
Subject: Allegro and SB05_DJ2 problem
Date: Sun, 02 Mar 1997 21:14:50 GMT
Organization: Southwest Missouri State University
Lines: 96
Message-ID: <3319eaa3.7656395@ursa.smsu.edu>
NNTP-Posting-Host: forseti.i175.smsu.edu
To: djgpp AT delorie DOT com
DJ-Gateway: from newsgroup comp.os.msdos.djgpp

I'm using the Sound Blaster Library by Joel H. Hunter, and have run into a
problem when using Allegro's graphics functions with it.  The MOD player built
into the Sound Blaster Library stops at random places within the MOD or starts
playing an extremely mangled version of the actual music.  It appears to be
caused by something Allegro does, since it works fine if I remove all the
Allegro calls.  I am using DJGPP 2.01, Allegro 2.2  and version 0.5 of the Sound
Blaster Library.  If anyone has experienced this problem, please let me know. 
Here is my offending code from a file called "credits.cc":

#include <conio.h>
#include <allegro.h>
#include <credits.h>
#include <data1.h>
#include <dialogue.h>
#include <main.h>
#include <sb_lib.h>
#include "keyb.h"

#define NUM_CREDITS             4

void RollTheCredits(void)
  {
  DATAFILE                    * GrabberFile;
  BITMAP                      * Bitmaps[NUM_CREDITS];
  BITMAP                      * WorkScreen;
  int                           Coords[][2] = { {0,500},
                                                {0,700},
                                                {0,900},
                                                {0,1100},
                                              };
  int                           NumVerticalPixels;
  int                           Count;
  int                           ScreenWidth = 640;
  int                           ScreenHeight = 480;
  sb_mod_file                 * Music;

  allegro_init();
  if ( (GrabberFile = load_datafile("data1.dat")) == NULL)
    ExitWithError("Can't load credits data file");
  Bitmaps[0] = (BITMAP *)GrabberFile[TITLE].dat;
  Bitmaps[1] = (BITMAP *)GrabberFile[COPYRIGHT].dat;
  Bitmaps[2] = (BITMAP *)GrabberFile[DESIGNER].dat,
  Bitmaps[3] = (BITMAP *)GrabberFile[ALLEGRO_CREDIT].dat;
  WorkScreen = create_bitmap(640,480);
  set_gfx_mode(GFX_AUTODETECT,640,480,0,0);
  set_pallete((RGB *)GrabberFile[CREDITS_COLORS].dat);

  if (sb_install_driver(8000) !=   SB_SUCCESS)
    ExitWithError("Can't install MOD player");
  if ( (Music = sb_load_mod_file("alienrad.mod")) == NULL)
    ExitWithError("Can't load MOD file");
  for (Count = 0;Count < NUM_CREDITS;Count++)
    Coords[Count][0] = (ScreenWidth - (*Bitmaps[Count]).w) / 2;
  sb_mod_play(Music);

  while (1)
    {
    if (!sb_mod_active)
      {
      sb_uninstall_driver();
      unload_datafile(GrabberFile);
      destroy_bitmap(WorkScreen);
      allegro_exit();
      return;
      }
    NumVerticalPixels = 0;
    while (Coords[NUM_CREDITS - 1][1] > -300)
      {
      clear(WorkScreen);
      for (Count = 0;Count < NUM_CREDITS;Count++)
        {

blit(Bitmaps[Count],WorkScreen,0,0,Coords[Count][0],Coords[Count][1],(*Bitmaps[Count]).w,(*Bitmaps[Count]).h);
        Coords[Count][1] -= 2;
        }
      NumVerticalPixels += 2;
      blit(WorkScreen,screen,0,0,0,0,ScreenWidth,ScreenHeight);
      if (kbhit() != 0)
        {
        if (getch() == ESCAPE)
          {
          sb_uninstall_driver();
          unload_datafile(GrabberFile);
          destroy_bitmap(WorkScreen);
          allegro_exit();
          return;
          }
        }
      }
    for (Count = 0;Count < NUM_CREDITS;Count++)
      Coords[Count][1] += NumVerticalPixels;
    }
  }