How can the gl_position be modified

[wddl]

Is your feature request related to a problem? Please describe.
I need to set gl_Position in the vertex shader, but in device domain cannot change z value through clipSpaceTransform matrix and only in device domain clipSpaceTransform can be set, how can the gl_position be modified?
refer to #7662 (comment)

Describe the solution you'd like
engine support modify gl_Position in vertex shader

Describe alternatives you've considered

OS and backend

[romainguy]

Sorry for the miscommunication earlier, clipSpaceTransform is the right parameter to use in device domain. You can see for yourself that it's a mat4 applied to the position written out to gl_Position.

[romainguy]

Note however that we do the following:

#if defined(VERTEX_DOMAIN_DEVICE)
// GL convention to inverted DX convention (must happen after clipSpaceTransform)
position.z = position.z * -0.5 + 0.5;
#endif

So when you expect a Z position in clip space at 0.0 it will actually be at 0.5 (in the domain 0..1).

[wddl]

@romainguy thank you very much！
I understand！