mapping lighting area with camera view area

OpenGL
1

Hi

How can I map a lighting area between my camera viewing are? I want to know which part of object will be seeing.

Thanks in advance

W

2

Hi wohrlof,

Could you expand a bit on your question? I’m guessing that people are a little puzzled by it.

Then again, maybe it’s just me.

3

Hi Graham

OK I want to define zone which are based on visual cue positions, camera positions and lighting conditions. Therefore I need to map my lighting zone with my camera. So I have few questions:
1-How can I find lighting zones in my scene?
2-How can I get the view volume of a camera?
3-How can I map the two to get my result?

I have tried to use the depth buffer but as I worked with Coin3d I have few problem to get a good result.

Thanks

W

4

It’s not clear to me what you mean by “lighting zone.” Do you mean the 3D view volume of a spot-light? Or maybe you mean all the pieces that remain after subtracting the world from it.

I’ll assume you mean some combination of the two, that you want to intersect a 3D light volume of some kind with the camera view volume. One way to do this is to create polyhedrons from the respective frustra, then perform an intersection. The plane equations of each frustum you should already have, since they’re required to define those volumes in the first place. The intersection itself can be performed by clipping the light volume(s) to the camera frustum’s positive half-spaces.

By the way, I had to Google for Coin3D. For 1800 euros, that must be one whale of a tool.

5

Ok I have use google to translate bu lighting zone I mean the enlightened parts of the scenes.
I want to get all these positions.
Coin3D is the free version of Open Inventor.

Thanks

W