object detection | GameDev.net

Original Post

Oct 7, 2001 at 3:35 PM

Hi say you have a torch and you want it to shine only on the front face of a cube - how can this be achieved - so basically the cube or the torch could be moved in any orientation but the torch shines on front face of the cube when it detects it any ideas?? cheers

Null and Void

163

Null and Void

Oct 7, 2001 at 4:14 PM

Calculate the normal for the face and the torch, then use the dot product of those normals to get an angle depicting how closely they face one another. Then make the ''lightness'' a factor of how close the angle is to them facing each other.

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ogl

Author

ogl

Oct 8, 2001 at 5:23 AM

any sample code or demos where this is done?

cheers

wolfman8k

Oct 8, 2001 at 9:39 AM

Just use OpenGL''s lighting.

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