Thread: pacman collision

In my pacman game my tiles and pacman are 32x32 and I move them by 32px. However, sometimes if pacman collides with a ghost, pacman's face becomes the ghost's face. Could having the Collision checking within my Input function be part of the problem?

I have asked this question on the Allegro.cc forum and they say that I should be using box bound collision instead of tile collision. Is this true?

without code or visual aid i cant say but it sound like your draw ordering.

I have included the code for my Input function and all functions releating to drawing to the screen.

Thank you all for your help.

Code:

void getInput(void)
{
	pacman.oldx = pacman.x;
	pacman.oldy = pacman.y;

	if(key[KEY_UP]  && pacman.y > 0)
	  {           // && level[pacman.y-1][pacman.x] != 1
		 pacman.y--;		        pacman.sprNum = PACMAN4_BMP;
		 pacman.direction = UP;
	  }
	else if(key[KEY_DOWN] && pacman.y < 14)
		{   // && level[pacman.y+1][pacman.x] != 1
			pacman.y++;
			pacman.sprNum = PACMAN1_BMP;
			pacman.direction = DOWN;
		}
	else if(key[KEY_LEFT] && pacman.x > 0)
		{  //  && level[pacman.y][pacman.x-1] != 1
		  pacman.x--;
		  pacman.sprNum = PACMAN3_BMP;
		  pacman.direction = LEFT;
		}
	else if(key[KEY_RIGHT]  && pacman.x < 19)
		{    //&& level[pacman.y][pacman.x+1] != 1
			pacman.x++;
			pacman.sprNum = PACMAN2_BMP;
     		pacman.direction = RIGHT;
		}

	else if(key[KEY_PRTSCR])
		{
			savescreen();
		}
   else if(key[KEY_M])
      {
         if(music == 1)
          { music = 0;
            midi_pause();
          }
         else
          { music = 1;
          midi_resume();
          }
      }
	else if(key[KEY_ESC])
		{
			gui_bg_color = 255;
			gui_fg_color = 0;
			play_sample(sound[SOUND5_WAV].dat,255,128,1000,FALSE);
			if(alert("Are you sure", "you want to", "Quit?","&Yes","&No",'y','n') == 1)
				quit = 1;
		}

   checkCollision();
   level[pacman.y][pacman.x] = 0;
   levelScent[pacman.oldy][pacman.oldx] = pacman.direction;
}

void drawscreen(void)
{
   int i;
	clear_to_color(buffer,0);
   acquire_screen();
	drawBackground();
 	drawLevel();
	masked_blit(graphic[pacman.sprNum].dat,buffer,0,0,pacman.x*32,pacman.y*32,32,32);

   for(i = 0; i < 3; i++)
   {
	blit(graphic[BGBLOCK_BMP].dat,buffer,0,0,ghosts[i].x*32,ghosts[i].y*32,32,32);
	masked_blit(graphic[ghosts[i].sprNum].dat,buffer,0,0,ghosts[i].x*32,ghosts[i].y*32,32,32); // blue ghost
   }

   //	textprintf(buffer,font,1,1,15,"x:%d y:%d dots:%d pacman.flee: %d",pacman.x,pacman.y, dots, pacman.flee);
//	textprintf(buffer,font,1,1,15,"super_pill_timer:%d pacman.flee: %d",super_pill_timer, pacman.flee);
	textprintf(buffer,font,1,1,15,"music:%d",music);
	textprintf(buffer,font,290,1,9,"Lives:%d",pacman.lives);
	textprintf(buffer,font,290,11,9,"Score:%d",pacman.score);
	textprintf(buffer,font,290,21,9,"Level:%d",levelNum);
	blit(buffer,screen,0,0,0,0,640,480);
   release_screen();
}
/*****************************************************************************/
void drawLevel(void)
{
	int i,j;
	for(i = 0; i < 20; i++)
	{
		for(j = 0; j < 15;j++)
		{
			switch(level[j][i])
			{
				case 1 :	blit(graphic[BLOCK_BMP].dat,buffer,0,0,i*32,j*32,32,32);
							break;
				case 3 : masked_blit(graphic[DOT_BMP].dat,buffer,0,0,i*32,j*32,32,32);
							break;
				case 4 : masked_blit(graphic[bonus.sprNum].dat,buffer,0,0,i*32,j*32,32,32);
							break;
				case 8 : masked_blit(graphic[BONUS4_BMP].dat,buffer,0,0,i*32,j*32,32,32);
							break;
			}
		}
	}
}
/*****************************************************************************/
void drawBackground(void)
{
	int i,j;
	for(i = 0; i < 20; i++)
	{
		for(j = 0; j < 15;j++)
		{
			if(level[j][i] != 1)
				blit(graphic[BGBLOCK_BMP].dat,buffer,0,0,i*32,j*32,32,32);

		}
	}
}

well, if you wan pacman always on top(ie he's visible even when he shares a space with the ghost) you should draw him after you draw the ghosts.

draw order like so

background:
level:
ghosts:
pacman:

is that what your lookin for?