Message-Id: <3.0.32.19970805205511.0068719c@m1.261.telia.com>
Date: Tue, 05 Aug 1997 20:56:41 +0200
To: djgpp AT delorie DOT com
From: Daniel Mattsson <daniel DOT mattsson AT gavle DOT mail DOT telia DOT com>
Subject: Allegro Sprite Problem
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Hi everyone!

I'm a newbie at Allegro but i have a little problem.
I have made a little program with 4 buttons and you
push them an a sprite moves on the screen. You control
the movement by using the four buttons. The problem is 
that when i move around the sprite it leave line of itself
in strange places over the screen. For example when i move
it up suddenly a line from the sprite appears 20-30 pixels up...

I hope someone can help me.. This is the program, i apologize 
if it's too long.

/* Test.c */
#include <stdio.h>
#include <stdlib.h>
#include <allegro.h>
#include "gui_dat.h"

DATAFILE *gui_data;
BITMAP *tmp_bmp;
PALETTE *norm_pal;

BITMAP *player;
BITMAP *back_player;
int player_x = 200;
int player_y = 200;
int step = 4;


void redraw_player(int p_direct);
int left_button_proc(int msg, DIALOG *d, int c);
int right_button_proc(int msg, DIALOG *d, int c);
int up_button_proc(int msg, DIALOG *d, int c);
int down_button_proc(int msg, DIALOG *d, int c);

DIALOG the_dialog[] =
{
   /*(dialog proc)      (x)   (y)   (w)   (h)   (fg)  (bg)  (key) (flags)
(d1)  (d2)  (dp) */
   { left_button_proc,  100,  100,  20,   20,   34,    75,    0,    D_EXIT,
 0,    0,    "<" },
   { right_button_proc, 120,  100,  20,   20,   34,    75,    0,    D_EXIT,
 0,    0,    ">" },
   { up_button_proc,    110,   80,  20,   20,   34,    75,    0,    D_EXIT,
 0,    0,    "^" },
   { down_button_proc,  110,  120,  20,   20,   34,    75,    0,    D_EXIT,
 0,    0,    "v" },
   { NULL,                0,    0,   0,    0,   34,    75,    0,    0,
 0,    0,    NULL}

};

void redraw_player(int p_direct)
{
  if (p_direct != 0)
    blit(back_player, screen, 0, 0, player_x, player_y, player->w, player->h);

  if (p_direct == 8) player_y -= step;
  if (p_direct == 2) player_y += step;
  if (p_direct == 4) player_x -= step;
  if (p_direct == 6) player_x += step;

  blit(screen, back_player, player_x, player_y, 0, 0, player->w, player->h);

  draw_sprite(screen, player, player_x, player_y);
}


int left_button_proc(int msg, DIALOG *d, int c)
{
  int ret;
  ret = d_button_proc(msg, d, c);
  if (ret == D_CLOSE)
  {
    redraw_player(4);
    return D_REDRAW;
  }
  return ret;
}

int right_button_proc(int msg, DIALOG *d, int c)
{
  int ret;
  ret = d_button_proc(msg, d, c);
  if (ret == D_CLOSE)
  {
    redraw_player(6);
    return D_REDRAW;
  }
  return ret;

}

int up_button_proc(int msg, DIALOG *d, int c)
{
  int ret;
  ret = d_button_proc(msg, d, c);
  if (ret == D_CLOSE)
  {
    redraw_player(8);
    return D_REDRAW;
  }
  return ret;

}

int down_button_proc(int msg, DIALOG *d, int c)
{
  int ret;
  ret = d_button_proc(msg, d, c);
  if (ret == D_CLOSE)
  {
    redraw_player(2);
    return D_REDRAW;
  }
  return ret;

}

int main()
{
  allegro_init();
  install_keyboard();
  fade_out(3);
  install_mouse();
  install_timer();

  gui_data = load_datafile("gui.dat");
  norm_pal = (PALETTE *)gui_data[button_pal].dat;
  player = (BITMAP *)gui_data[normal_button].dat;
  back_player = create_bitmap(player->w, player->h);

  set_gfx_mode(GFX_AUTODETECT, 640, 480, 0, 0);
  set_pallete(*norm_pal);

  tmp_bmp = (BITMAP *)gui_data[background].dat;
  blit(tmp_bmp, screen, 0, 0, 0, 0, tmp_bmp->w, tmp_bmp->h);
  redraw_player(0);

  do_dialog(the_dialog, -1);

  readkey();
  return 0;

}