On Jul 17, 4:07=A0am, "Ron Francis" <ronfran...@[EMAIL PROTECTED]
> wrote:
>
> 1: I need to implement shadows. Without going into detail, at the moment
=
I
> create a volume shadow from each triangle and use a stencil buffer to
> display it.
> Is there a similar technique in OGL? (This has it's own problems when
> rendering fog because the stencil is right at the front of the viewing
> frustum, but at least I get ray traced shadows.)
>
As a basic rule, anything with hardware acceleration in Direct3D
should also be in OpenGL. You don't say how you're doing shadows
but OpenGL definitely has stencil.
> 3. I also need to render an off-centre window. In DX, I can do it with
th=
e
> function D3DXMatrixPerspectiveOffCenterLH( );
> It would be similar to rendering only a subsection of a scene. The
camera
> would be at (0,0,0) and aiming along the z axis, but the window would
onl=
y
> render a section off to the left or right. Is this possible?
>
glFrustum() does this, or just copy/paste the code from
the docs for D3DXMatrixPerspectiveOffCenterLH( ) and
use those values.
> I have more concerns, but these are the major ones.
> Please let me know if there is a more appropriate newsgroup.
Question 2 would be better in comp.graphics.algorithms
> Any advice will be much appreciated.
Assuming you're using C++: First of all, separate out your
rendering code and create an abstract wrapper class to
encapsulate the functions.
Implement the class in Direct3D, and later OpenGL. That
way you can switch between them.
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