checking object's visibility

Original Post

Nov 20, 2004 at 12:20 PM

I want check if my object is visible on my viewport. I.e, if my camera looks at object, my function returns true etc.

Nov 20, 2004 at 2:17 PM

Try reading throuhg these two papers to get a gist of what has to happen:
Frustum Culling
Geometry Culling in 3D Engines

If you're having trouble with collision-detection, try this page:
3D Object Intersection

MikeyO

Nov 21, 2004 at 11:55 AM

If the object is just a point, then you can check it really easily with something like:

Vector3 projected = Vector3.Project(occPosition, viewPort, Projection, View, World);if(((projected.X > viewPort.Width) || (projected.X < 0)) || ((projected.Y > viewPort.Height) || (projected.Y < 0))) //Offscreen test 1	return;Vector3 forward = Vector3.Scale(Vector3.Normalize(Vector3.Unproject(centerScreen, viewPort, Projection, View, World)), 20);if(Vector3.Subtract(forward, occPosition).Length() < Vector3.Subtract(Vector3.Multiply(forward, -1), occPosition).Length())//Offscreen test 2	return;//Draw object here @ occPosition vector

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