- _ProjectionParams.x

I want to figure out what _ProjectionParams.x means. The doc said:

But, what is a flipped projection matrix? I tried to use a filpped camera with the script in Unity - Scripting API: MonoBehaviour.OnPreCull()

but the _ProjectionParams.x is still equal to 1.0, not -1.0.

So, when will _ProjectionParams.x be -1.0?

- unity_CameraInvProjection

The projection matrix of perspective camera is not invertible in math, because its determinant is zero. So why there is a matrix called invert projection? How to use it?

- unity_CameraWorldClipPlanes[6]

The doc said:

How does float4 define the equation? What does xyzw mean?

- unity_CameraProjection

Is it equal to UNITY_MATRIX_P?

- unity_OrthoParams

The doc said:

But I think y is equal to the size of Camera component, which is half size of height of the frustum. Right?