stencil write mask

[quicklyslow]

I find that the stencil write mask in DX(StencilWriteMask) and OpenGL(glStencilMask not called) are all set to 0xff in bgfx.

Is there any way I can change this stencil write mask?

In fact, I came across a problem because this stencil write mask. I want to implement a clipRect in clipRect UI, at most 8(each a stencil value bit) nested clipRects. The stencil value I set to each clipRect is 2^n(1, 2, 4...128), with the stencil write mask set to the same value, the value in stencil buffer after replace will be(1, 3, 7...255):

stencil value in buffer= (ref(2^n) & stencil write mask) | (stencil value in buffer now) & (~stencil write mask)

Then I will set stencil op to Equal to (1, 3, 7...255) and keep to do stencil test. That will be all right.

But I can't change the stencil write mask through bgfx(maybe I do not find it), so if the inner clipRect is smaller than the outer, there will be no problem with the stencil write mask being 0xff, I can test stencil by set stencil value to 2^n and Ref the same, but if the inner clipRect is bigger than the outer one, then the inner one will not be clip by the outer one.

I'm sorry that I don't know whether I express the problem clearly, and if there is something wrong, please forgive my ignorance about that.

[Andos]

Any news on this?

Practically all platforms support stencil write masks. How come BGFX doesn't? :-)

Metal: https://developer.apple.com/documentation/metal/mtlstencildescriptor/1462496-writemask Vulkan: https://www.khronos.org/registry/vulkan/specs/1.2-extensions/man/html/VkStencilOpState.html OpenGL: https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/glStencilMask.xhtml

[bkaradzic]

Any news on this?

No news.

Practically all platforms support stencil write masks. How come BGFX doesn't? :-)

It wasn't really requested hard by users.

[pollend]

I noticed it is in the opengl codebase but it was commented out any particular reason why this is the case? doesn't seem like it would be too much to support.