Re: [cc65] TGI preview

From: Anthony Lawther <>
Date: 2009-11-20 02:20:30
On 20/11/2009, at 8:40 AM, Ullrich von Bassewitz wrote

> The limits cannot be given as definite values, because a formula like
>   tgi_clip_y1 += (tgi_xmax - tgi_clip_x1) * tgi_clip_dy / tgi_clip_dx
> is calculated. So larger X values are acceptable if the Y values  
> are small and
> vice versa. But possible coordinates are definitely much larger  
> than +/- 2^10.
> My estimate is that anything up to 2^14 is safe. In my case I had  
> generated a
> value near 2^15 because of the error.
> What I don't like is the idea that the routine just hangs for these  
> values.

Would it make sense for the line clipper to return the extreme legal  
value in the event of overflow?

This will allow execution to continue and any output affected by this  
should give the programmer an idea where to look to fix it.


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Received on Fri Nov 20 02:20:55 2009

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