Faster sine/cosine?

[Musashimaru]

Isn't there a faster way to calculate sine/cosine?

After I included about 60 sine/cosine functions per frame my framerate went down by about 1000(!)%

[kedaman]

It's because they use your math processor. You need to setup a trignonometry table by declaring arrays and store the trig functions results in them. Then use these arrays instead of vb's trignonometry functions.

[ravcam]

Wouldn't this limit presision depending on how far the function is caried out in the array... if he wants to stay acurate to say 5 or 6 decimal places the vbTrig functions might be the most practical way. ( I think... but I have been wrong in the past)

[kedaman]

If you don't have memory problems you can make your table as huge as you want, it depends on what you're doing, you said your having frame rates, i guess youre working on a 3d-engine, i had the same problem solved it this way.

[Paul282]

I remember once writing a program to rotate a 3d matrixed box. I just threw in a heap of constants because they compile to just their values.

A better way would be to calculate a whole heap of trigs on form load and write them to an array, then just call them.

Instead of X=Cos(45) (the function)

you have X = MyCos(45) (the array)

where the index was written with the cos of that number

It also means you can work directly in degrees and not radians.

Dim MyCos(360) as single
I = 45
MyCos(I) = COS(I) '(*180/pi) or whatever it is to convert from radians.

so MyCos(i) = 0.70711

Sorry for the math, it's early and I can't be bothered working it out exaclty, you get the idea

[Musashimaru]

The (co)sine table will do fine. I think I won't need much more than 1 value/degree.

Thank you for your replies!

-Musashimaru

[Paul282]

Is that MusashiMaru as in the Hawaian Sumo Wrestler?

[Musashimaru]

O yeah!

btw. It's only a nick. I'n not (shock!) the real Musashimaru :-)