> Having trouble here .. Im making a polygon filler, and I'm having trouble
> scanning the sides of it. I started coding optimized right at the
begining, but
> as probelms started to surface, i did it as simple as possible, using
real's and
> all, but it still wont work. So, I guess I'm doing something
fundamentally
> wrong. The rutine is included here.. Its supposed to be able to draw
lines with
> only one X pixel for every Y line. This -should- be simple.. argh!

> I'd appreciate a fix for it, preforably -with- an explenaiton :)

> -------- CUT --------

> Procedure SwapInt(var a,b:Integer);
> Var C : Integer;
> Begin
>      c:=a;
>      a:=b;
>      b:=c;
> End;

> Procedure ScanLine(x1,y1,x2,y2,c:Integer);
> Var Step  : Real;
>     Xcount: Real;
>     Teller: Integer;
> Begin
>      If Y1=Y2 then Exit;
>      If Y2<Y1 then
>      Begin
>       SwapInt(Y1,Y2);
>       SwapInt(X1,X2);
>      End;
>      Step:=(X2-X1)/(Y2-Y1);
>      XCount:=Step;
>      For Teller:=Y1+1 to Y2 do
>      Begin
>       Mem[$a000:Round(XCount)+Teller*320]:=C;
>       XCount:=XCount+Step;
>      End;
> End;

>> Procedure SwapInt(var a,b:Integer);
>> Var C : Integer;
>> Begin
>>      c:=a;
>>      a:=b;
>>      b:=c;
>> End;

>> Procedure ScanLine(x1,y1,x2,y2,c:Integer);
>> Var Step  : Real;
>>     Xcount: Real;
>>     Teller: Integer;
>> Begin
>>      If Y1=Y2 then Exit;
>>      If Y2<Y1 then
>>      Begin
>>       SwapInt(Y1,Y2);
>>       SwapInt(X1,X2);
>>      End;
>>      Step:=(X2-X1)/(Y2-Y1);
>>      XCount:=Step;
>>      For Teller:=Y1+1 to Y2 do
>>      Begin
>>       Mem[$a000:Round(XCount)+Teller*320]:=C;
>>       XCount:=XCount+Step;
>>      End;
>> End;

>Why are you starting xcount at step? Also use fixed point arithmetic.

> >> Ramiro:
> > >Why are you starting xcount at step? Also use fixed point arithmetic.
> [...]
> > Kim Robert Blix:
> > then it should become obvious that it doesnt work. What do you mean by
> Fixed
> > point arithmetic" btw?

>         Fixed point math is another way of doing floating point arithmethic
> operations using INTEGERS (!). That's it.
>         Why would we want to use Integers instead of a Real variable? Because
> working with Reals is s-l-o-w, because Reals are 6-bytes long while
> integers are 2-bytes long (thought they don't have the same decimal
> accuracy) and sometimes you need the most speed possible. Fixed point math
> can be applyied to other types, not only integers.

>                                                 Jaguar/Negative Edge

> >> Ramiro:
> > >Why are you starting xcount at step? Also use fixed point arithmetic.
> [...]
> > Kim Robert Blix:
> > then it should become obvious that it doesnt work. What do you mean by
> Fixed
> > point arithmetic" btw?

>         Fixed point math is another way of doing floating point arithmethic
> operations using INTEGERS (!). That's it.
>         Why would we want to use Integers instead of a Real variable? Because
> working with Reals is s-l-o-w, because Reals are 6-bytes long while
> integers are 2-bytes long (thought they don't have the same decimal
> accuracy) and sometimes you need the most speed possible. Fixed point math
> can be applyied to other types, not only integers.

>                                                 Jaguar/Negative EdgeHow do you implement fixed point math without lossing the

> >> Ramiro:
> > >Why are you starting xcount at step? Also use fixed point arithmetic.
> [...]
> > Kim Robert Blix:
> > then it should become obvious that it doesnt work. What do you mean by
> Fixed
> > point arithmetic" btw?

>         Fixed point math is another way of doing floating point arithmethic
> operations using INTEGERS (!). That's it.
>         Why would we want to use Integers instead of a Real variable? Because
> working with Reals is s-l-o-w, because Reals are 6-bytes long while
> integers are 2-bytes long (thought they don't have the same decimal
> accuracy) and sometimes you need the most speed possible. Fixed point math
> can be applyied to other types, not only integers.

>                                                 Jaguar/Negative EdgeHow do you implement fixed point math without lossing the

> oh dear.  Someone has never heard of the pentium processor and it's
> fpu.  Nowadays you can run off a floating point calculation faster
> than an integer calculation, (and after that, you can start pipelining
> calculations and make then *really* fast).

>    Fixed point math is another way of doing floating point arithmethic
>operations using INTEGERS (!). That's it.

> Matt Parkins wrote:

> > >working with Reals is s-l-o-w, because Reals are 6-bytes long while
> > >integers are 2-bytes long

> > oh dear.  Someone has never heard of the pentium processor and it's
> > fpu.  Nowadays you can run off a floating point calculation faster
> > than an integer calculation,

> Are 6-byte reals handled by the FPU? I don't know. I would make a test
> program, but I'm sure someone here already knows the answer.

>> Are 6-byte reals handled by the FPU? I don't know. I would make a test
>> program, but I'm sure someone here already knows the answer.

>Buried somewhere in the BP/TP manuals is a comment that all fpu
>operations are done as extendeds.