# DX11 DX11 - Lighting - Does it affect the mesh?

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Hi guys! Again!

Lets imagine that I have a sample scene where I have a huge plane and a point light. Now I'm trying to figure out if the light is going to affect the plane.

I would Imagine that in this example I had to use sphere to plane collision, but Imagine that I had a more complicated mesh, like a building, what would I do there?

So the question is, how can I check weather that the point lights is going to affect a complex mesh on the CPU, real time?

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I would make 6 light "cameras" (like for cube map reflection) and cull (frustum, occlusion queries...) objects for each. But first normally  you cull from player view each light face.

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But just because the point light can see the mesh as a camera, doesn't mean that the light reaches the mesh

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Camera has a far clip plane (light range) so it doesn't reach mesh.

Edited by belfegor

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Mesh has a bounding sphere, light has a bounding sphere; do an intersection test -> if they intersect then the light effects it.

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Mesh has a bounding sphere, light has a bounding sphere; do an intersection test -> if they intersect then the light effects it.

That will not work for Directional Lights. Just wanted to give my two cents on it.

Edited by BornToCode

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Mesh has a bounding sphere, light has a bounding sphere; do an intersection test -> if they intersect then the light effects it.

That will not work for Directional Lights. Just wanted to give my two cents on it.

His only concern is just point lights at this moment. But if he would check for directional lights he can just use the camera's generated PVS frustum culling.

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