From:	"Matt Kris" <jdkris AT NOPOOPalpha DOT delta DOT edu>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Sprite help...
Date:	Mon, 12 Jan 1998 22:49:05 -0500
Organization:	Delta College
Lines:	130
Message-ID:	<69eoci$6gk@alpha.delta.edu>
NNTP-Posting-Host:	pm090-01.dialip.mich.net
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Howdy....

Could someone out there help me out and convert this code so that it uses
Allegro and load a 10x10 bitmap from a file.  Right now it defines all of
its own functions and doesn't load the bitmap from a file. Thanks alot.

#include <sys/nearptr.h>
#include <go32.h> /* for _dos_ds */
#include <dos.h>
#include <stdlib.h>
#define GRAPHICS        0x013
#define TEXT            0x03
char *video_buffer = (char *)0xa0000;
typedef struct sprite_type {
 unsigned x, y;                  /* location */
 unsigned x_vel, y_vel;          /* velocity */
 char width, height;             /* dimensions */
 char num_frames;                /* number of frames */
 char cur_frame;                 /* current frame */
 char *background, **frame;
} sprite;
void Set_Video_Mode(int mode)
{
 union REGS regs;
 regs.x.ax = mode;
 int86(0x10, &regs, &regs);
}
void plot_pixel(short int x, short int y, char color)
{
 video_buffer[(y << 8) + (y << 6) + x] = color;
}
void bit_blt(int x, int y, char *bitmap)
{
 int yindex, offset = (y << 8) + (y << 6) + x;
 char width = bitmap[0], height = bitmap[1];
 bitmap += 2; /* skip the first two bytes */
 for (yindex = 0; yindex < height; yindex++) {
  memcpy((char *)video_buffer+offset,bitmap,width);
  offset += 320; /* next line of video buffer */
  bitmap += width; /* next line of bitmap */
 }
}
void reverse_bit_blt(int x, int y, char *bitmap)
{
 int yindex, offset = (y << 8) + (y << 6) + x;
 char width = bitmap[0], height = bitmap[1];
 bitmap += 2; /* skip the first two bytes */
 for (yindex = 0; yindex < height; yindex++) {
  memcpy(bitmap,(char *)video_buffer+offset,width);
  offset += 320; /* next line of video buffer */
  bitmap += width; /* next line of bitmap */
 }
}
void transparent_bit_blt(int x, int y, char *buffer)
{
 int xindex, yindex, offset = (y << 8) + (y << 6) + x;
 char width = buffer[0], height = buffer[1];
 buffer += 2; /* skip the first two bytes */
 for (yindex = 0; yindex < height; yindex++) {
  for (xindex = 0; xindex < width; xindex++) {
   if (buffer[xindex]) {
    video_buffer[offset+xindex] = buffer[xindex];
   }
  }
  offset += 320; /* next line of video buffer */
  buffer += width; /* next line of bitmap */
 }
}
void draw_sprite(sprite *sprite)
{
 sprite->x += sprite->x_vel; sprite->y += sprite->y_vel;
 reverse_bit_blt(sprite->x,sprite->y,sprite->background);
 transparent_bit_blt(sprite->x,sprite->y,sprite->frame[sprite->cur_frame]);
}
void erase_sprite(sprite *sprite)
{
 bit_blt(sprite->x,sprite->y,sprite->background);
}
char bitmap[102] = {
 10,10,                          /* width and height of block */
 15,15,15,15,15,15,15,15,15,15,  /* strip 1 */
 15,15,00,00,00,00,00,00,15,15,
 15,00,15,00,00,00,00,15,00,15,
 15,00,00,15,00,00,15,00,00,15,
 15,00,00,00,15,15,00,00,00,15,
 15,00,00,00,15,15,00,00,00,15,
 15,00,00,15,00,00,15,00,00,15,
 15,00,15,00,00,00,00,15,00,15,
 15,15,00,00,00,00,00,00,15,15,
 15,15,15,15,15,15,15,15,15,15   /* strip 10 */
};
int main(void)
{
 unsigned count;
 sprite sprite;
 __djgpp_nearptr_enable();
      video_buffer += __djgpp_conventional_base;
 Set_Video_Mode(GRAPHICS);
 sprite.x = 160;
      sprite.y = 100;
 sprite.x_vel = 1;
      sprite.y_vel = 1;
 sprite.width = 10;
      sprite.height = 10;
 sprite.num_frames = 1;
 sprite.cur_frame = 0;
 sprite.background = (char *)malloc(sprite.width*sprite.height+2);
 sprite.background[0] = 10; sprite.background[1] = 10;
 sprite.frame = (char **)malloc(sizeof(char *)*sprite.num_frames);
 sprite.frame[0] = (char *)&bitmap;
 for(count = 0; count < 32000; count++) {
                plot_pixel(rand() % 320, rand() % 200, rand() % 256);
 }
 while(!kbhit())
      {
         if((sprite.x > 309) || (sprite.x < 1))
            sprite.x_vel = -sprite.x_vel;
         if((sprite.y > 189) || (sprite.y < 1))
            sprite.y_vel = -sprite.y_vel;
    draw_sprite(&sprite);
    delay(10);
    erase_sprite(&sprite);
 }
 Set_Video_Mode(TEXT);
 __djgpp_nearptr_disable();
      exit(0);
}

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