[A83] Re: Faster Multiplication

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[A83] Re: Faster Multiplication


Division is not so essential for 3D. It is usually only performed when
converting from real world to screen coordinates. The intensive portion of
3D is the matrix multiplications. Matrix multiplications require O(n^3)
multiplications. In 3D, rotation matrices are usually 4x4, although you can
get by with 3x3. Therefore to manipulate a point requires 27
multiplications. Now it is more easily seen why I wrote this fast
multiplication routine. Multiplication is also useful in line clipping,
another thing that shows up in 3D programs.

For 83, it should be noted that the table can be reduced to 768 bytes if you
trade off some of the speed.

-----Original Message-----
From: assembly-83-bounce@lists.ticalc.org
[mailto:assembly-83-bounce@lists.ticalc.org]On Behalf Of
Mike3465@aol.com
Sent: Thursday, May 31, 2001 1:58 PM
To: assembly-83@lists.ticalc.org
Subject: [A83] Re: Faster Multiplication



Well, if people could figure out better multiplication and division
functions(anyone know of one for division?) and install those on the
processors, we could boost the fps on games quite easily, because 3d is so
heavily multiplication and division.  For example, to get a 3d point into 2d
cordinates(lets forget about multiplication and scalling and what ever):
x = x*(screen width/2(i think thats what the value is))/z;
y = y*(ditto)/z;

see the reason that 3d is so slow? thats 2, maybe 3 multiplication and
division things to do(I think thats the general way to do it.)

But then we also have to get into the texture mapping and what ever.

But as it stands right now, they are trying to speed up the texture mapping,
light/shadows, and so on.  But anyways, I should also say that, the 83
programs are graphically lesser then most windows programs, but also,
windows
games probably use a level of alpha blending, which is a pain multiplication
ways, unless you use a rather large preset and what not.

But anyways, I'm just saying, that I personally go for speed and size,
favoring speed of course, but I never even seen anything like that.... Or
anything even remotly close.
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