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J_M

Where is the Project plane

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Hi all, I'm confused when setting up transforms in DirectX. I knew view transform is used to project a entity in world space into the camera space. My question is where is the project plane? when setting up the camera space. Thanks

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There's not a single projection plane, you have a 3D projection volume that's frustum-shaped. This volume has two planes that are perpendicular to the camera, typically referred to as the near clipping-plane and the far clipping-plane. Anything renderered must be between those two planes, and also between the other 4 planes that make up the frustum volume. The distance from the camera to those tow planes is usually specified as a parameter when creating the projection matrix, for example when using D3DXMatrixPerspectiveLH.

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Thanks, MJP.

Yes, using the near plane and far plane, we can set up the frustum. I think the next step is D3D will projet the objects including in the frustum to a 2d plane. And then objects on the 2D plane will be display on the screen. The 2D plane is the projection plane, am i right?

I'm wondering where is the 2D plane(projection plane). Does it on the camera position or near plane?

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The camera position is a point, and exists on an infinite number of possible planes. The nature of projection is also that it looks the same no matter where you place the projection 'plane' between you and the objects being rendered, so really there doesn't need to be such a plane. You just project straight to the screen space. But it may be helpful to consider the near clipping plane to be where you're projecting onto, since nothing closer than that will be projected.

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