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From: kevin@crash.cts.com (Kevin Hill)
Newsgroups: comp.sys.mac.programmer
Subject: This code is buggy and I don't know why, any help out there?
Message-ID: <8676@crash.cts.com>
Date: 19 Apr 91 08:39:53 GMT
Sender: root@crash.cts.com
Lines: 225


 This code seems to hang the computer after moving the image for several seconds

Could anyone help me out and point out any obvious bugs that my slow brain has missed?  Thanks.

Q
#include "rail.h"
#include <stdio.h>
#include <storage.h>
#include <math.h>
 
 
extern		long			(*track)[GYMAX];
extern		int			gx,gy,x1,y1;
extern		WindowPtr	thewind;
			ImagePtr		first_image;
			Handle		train_image;
 
 
set_facing(train)
	ImagePtr		train;
{
	int		i,j,x,y;
	
	i = 0;
	j = -1;
	
	x = train->where.left/32;
	y = train->where.top/32;
	
	i = train->facing;
	if (i == -1)
	{
		i++;
		while( (track[x][y] & (int)pow(2,i)) == 0)
		{
			i++;
			if (i== 8)
				ExitToShell();
		}
		j = i;
	}
	else
	{
		if ((i-1) == -1)
			if ( (track[x][y] & (int)pow(2,7)) != 0)
				j = 7;
		if ((i+1) == 8)
			if ( (track[x][y] & (int)pow(2,0)) != 0)
				j = 0;
		if ((i-1) != -1)		
			if ( (track[x][y] & (int)pow(2,i-1)) != 0)
				j = i -	1;
		if ( (track[x][y] & (int)pow(2,i)) != 0)
			j = i;
		if ((i+1) != 8)
			if ( (track[x][y] & (int)pow(2,i+1)) != 0)
				j = i + 1;
	}
	
	if (j == -1)
		return;
	else 
		i = j;
	
	if (i != train->facing)
	{
		train->facing = i;
		
		train->imap.baseAddr = (QDPtr)*train_image + (i * 32 * 6);
		train->imask.baseAddr = (QDPtr)*train_image + (96 + (i * 32 * 6));
	}
}
 
create_train()
{
	int			i = 0,x,y;
	ImagePtr	train,image_ptr = first_image;
	
	
	train = (ImagePtr)NewPtr(sizeof(Image));
	HLock(train);
	train->imap.rowBytes = 2;
	SetRect(&train->imap.bounds,0,0,16,16);
	train->imask.rowBytes = 2;
	SetRect(&train->imask.bounds,0,0,16,16);
	
	
	train_image = GetResource('SICN',130);
	HLock(train_image);
	
	if (train_image == NULL)
		ExitToShell();
	
	if (train == NULL)
		return;
	
	if (first_image == NULL)
		first_image = train;
	else
	{
		while(image_ptr->next != NULL)
			image_ptr = image_ptr->next;
		image_ptr->next = train;
		train->next = NULL;
	}
 
	train->type = Engine;
	
	if (track[gx][gy] == -1)
	{
		SysBeep(1);
		return;
	}
	
	SetRect(&train->where,(x1*32),(y1*32)+8,(x1*32)+16,(y1*32)+24);
	
	train->old.baseAddr = (QDPtr)NewPtr(32L);
	HLock(train->old.baseAddr);
	SetRect(&train->old.bounds,0,0,16,16);
	train->old.rowBytes = 2;
	
	train->facing = -1;
	set_facing(train);
 
	put_sicn(train);
}
 
 
put_sicn(image)
	ImagePtr		image;
{
	static	int	i = 1;
	
	if (i == 0)
		CopyBits(&image->old,&thewind->portBits,&image->old.bounds,
									&image->now,0,NULL);
	i = 0;
	
	
	CopyBits(&thewind->portBits,&image->old,
						&image->where,&image->old.bounds,0,NULL);
	CopyBits(&image->imask,&thewind->portBits,
						&image->imask.bounds,&image->where,srcBic,NULL);
	CopyBits(&image->imap,&thewind->portBits,
						&image->imap.bounds,&image->where,srcOr,NULL);
					
					
	SetRect(&image->now,image->where.left,image->where.top,
						image->where.right,image->where.bottom);
	
	move_image(image);
}
 
 
move_image(image)
	ImagePtr		image;
{
	Rect		box;
	
	
	SetRect(&image->where,image->now.left,image->now.top,
							image->now.right,image->now.bottom);
	
	box.top = (image->now.top/32) * 32;
	box.left = (image->now.left/32) * 32;
	box.bottom = (image->now.bottom/32) * 32;
	box.right = (image->now.right/32) * 32;
	
	box.top = image->now.top - box.top;
	box.left = image->now.left - box.left;
	box.bottom = image->now.bottom - box.bottom;
	box.right = image->now.right - box.right;
	
	if ((box.top == 8) && (box.left == 8))
		set_facing(image);
	
	switch(image->facing)
	{
		case 0:
			image->where.top--;
			image->where.bottom--;
			break;
		case 1:
			image->where.top--;
			image->where.right++;
			image->where.bottom--;
			image->where.left++;
			break;
		case 2:
			image->where.right++;
			image->where.left++;
			break;
		case 3:
			image->where.top++;
			image->where.left++;
			image->where.bottom++;
			image->where.right++;
			break;
		case 4:
			image->where.top++;
			image->where.bottom++;
			break;
		case 5:
			image->where.top++;
			image->where.left--;
			image->where.bottom++;
			image->where.right--;
			break;
		case 6:
			image->where.left--;
			image->where.right--;
			break;
		case 7:
			image->where.top--;
			image->where.left--;
			image->where.bottom--;
			image->where.right--;
			break;
		default:
		break;
	}
	
	put_sicn(image);
}