PDA

View Full Version : Calculate Normals for a irregular object



soblue
02-03-2002, 03:45 PM
I draw an object with about 150 faces.
and all of them is not regularly facing towards the viewer.

so... if I am going to enable lighting...
I have to set the normals for each face...
Is there any clever ways to get the normals?

Thanks.

john
02-03-2002, 05:25 PM
But, you make the normals? It's just yet another description of your object.

You could equally be asking;
- how do I know where I want to put my verticies?
- how do I know how to colour my verticies?
- how do I know how to define texture coordinates?

you KNOW hwo to define them because you know what it is that you want to draw. You know the normals of your vertex presumedly because _YOU_ know evertyhing about that point sample (where it is, what colour it is, how it's textured, and the surface normal at that point).

Having said that, tho', the cross product of the two vectors will give you an orthogonal vector.

cheers,
John