The Property "HlmsBaseProp::PsoClipDistance" is not working

[36yang]

System Information

• Ogre Version: ❔ ogre-next 3.0
• Operating System / Platform: ❔ win10
• RenderSystem: ❔ gl3+
• GPU: ❔ gtx960

Detailled description

I want to use the plane clipping function in OpenGL. I found that the HlmsBaseProp:: PsoClipDistance property in HlMS can be used, but it doesn't actually take effect after I set it. I also used the addClipPlane function in RenderSystem to add my clipping plane parameters, but none of them worked. Are these interfaces obsolete or will this function be implemented in future versions

Ogre.log

Callstack

[darksylinc]

I thought I had removed/deprecated addClipPlane() family of functions. Indeed they aren't functional right now, particularly because there wasn't a use case that could be used as a baseline to design the API.

There are various reasons to use clipping planes, and they are all different.

HlmsBaseProp::PsoClipDistance controls whether the shaders expect clip distance to be filled.

In OgreNext, this is used by Planar Reflections. But it can also be used by custom shader code in arbitrary ways, like Colibri does.

The effect you're looking for can be achieved with Hlms customization.
However OgreNext already has almost all of the code, it's just how to expose it via an API that's the problem:

When Camera::enableReflection is called the following Pbs code path will be triggered:

        if( isCameraReflected )
        {
            const Plane &reflPlane = cameras.renderingCamera->getReflectionPlane();
            *passBufferPtr++ = (float)reflPlane.normal.x;
            *passBufferPtr++ = (float)reflPlane.normal.y;
            *passBufferPtr++ = (float)reflPlane.normal.z;
            *passBufferPtr++ = (float)reflPlane.d;
        }

// AND...
        const Camera *camera = sceneManager->getCamerasInProgress().renderingCamera;
        if( camera && camera->isReflected() )
        {
            setProperty( kNoTid, HlmsBaseProp::PsoClipDistances, 1 );
            setProperty( kNoTid, HlmsBaseProp::GlobalClipPlanes, 1 );
            // some Android devices(e.g. Mali-G77, Google Pixel 7 Pro) do not support user clip planes
            if( !mRenderSystem->getCapabilities()->hasCapability( RSC_USER_CLIP_PLANES ) )
                setProperty( kNoTid, HlmsBaseProp::EmulateClipDistances, 1 );
        }

OgreNext should be able to support custom clip planes (not just when using reflections) with slight modifications to Ogre::Camera.