[2.1] Light masks

[devxkh]

how can i exlude an item affected from a light?

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OgreItemPtr->setLightMask(0x0000001);
      light->setLightMask(0x000000001);

this doesn't work...

[dark_sylinc]

Yeah, setLightMask won't work with Forward+ (or Deferred if we had it) as this information is lost.

With Forward+ you can use two pass_scenes though, to achieve a similar result:

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pass_scene
{
    //Render objects and lights that have (mask & 0x00000001) != 0
    visibility_mask 0x00000001
}
pass_scene
{
    //Render objects and lights that have (mask & 0x00000001) != 0
    visibility_mask 0x00000002
    //Only work on a subset of RenderQueues to skip from processing a lot of items from the common RQs (assumes you put your Item in RQ ID 2)
    rq_first 2
    rq_first 3
}

It's not the same because you will be altering the order in which objects are rendered, but it will achieve what you're asking for.

[Feanor16]

if i understand, that's not possible anymore to change the mask into our code?

i tried with

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addWorkspace( SceneManager *sceneManager,
                                           const CompositorChannelVec &externalRenderTargets,
                                           Camera *defaultCam, IdString definitionName, bool bEnabled,
                                           int position=-1, const UavBufferPackedVec *uavBuffers=0,
                                           const ResourceLayoutMap* initialLayouts=0,
                                           const ResourceAccessMap* initialUavAccess=0,
                                           const Vector4 &vpOffsetScale = Vector4::ZERO,
                                           uint8 vpModifierMask=0x00, uint8 executionMask=0xFF );

editing executionMask when i build my workspace but it doesn't work

[dark_sylinc]

if i understand, that's not possible anymore to change the mask into our code?

I don't understand what you mean.

i tried with

Code: Select all

addWorkspace( SceneManager *sceneManager,
                                           const CompositorChannelVec &externalRenderTargets,
                                           Camera *defaultCam, IdString definitionName, bool bEnabled,
                                           int position=-1, const UavBufferPackedVec *uavBuffers=0,
                                           const ResourceLayoutMap* initialLayouts=0,
                                           const ResourceAccessMap* initialUavAccess=0,
                                           const Vector4 &vpOffsetScale = Vector4::ZERO,
                                           uint8 vpModifierMask=0x00, uint8 executionMask=0xFF );

editing executionMask when i build my workspace but it doesn't work

I don't know what execution masks have to do with this.

[Feanor16]

Sorry, bad explain. i was looking for use an equivalent of

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viewport->setVisibilityMask(visibility);

but like the lights, it doesn't works

[dark_sylinc]

Sorry, bad explain. i was looking for use an equivalent of

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viewport->setVisibilityMask(visibility);

but like the lights, it doesn't works

Hi! Don't change the viewport's visibility mask, as the compositor will override your changes. It's a sort of hard to remove remnant from 1.x.

Set the visibility mask to the render_scene pass either by script (use visibility_mask keyword) or by code (change CompositorPassSceneDef).

[rujialiu]

Yeah, setLightMask won't work with Forward+ (or Deferred if we had it) as this information is lost.

Is it a limitation of Forward+ in general, or just a limitation of current implementation? For example, can we put the lighting mask of objects into the material, and light masks of lights into the global light list, and then we can test it in the pixel shader? Rendering multiple scene passes seem to be troublesome if we have transparent object.

[dark_sylinc]

[quote="dark_sylinc"Is it a limitation of Forward+ in general, or just a limitation of current implementation? For example, can we put the lighting mask of objects into the material, and light masks of lights into the global light list, and then we can test it in the pixel shader? Rendering multiple scene passes seem to be troublesome if we have transparent object.

If you're asking if it can be done, yes... it can be done. But doing the mask comparison in the pixel shader will cost performance. If you really need it, then I guess I could implement it and have it globally disabled by default (to save performance to those who don't need the feature).

[rujialiu]

If you're asking if it can be done, yes... it can be done. But doing the mask comparison in the pixel shader will cost performance. If you really need it, then I guess I could implement it and have it globally disabled by default (to save performance to those who don't need the feature).

Please do it! We want it *desperately* And at least another user (the original author of this post) is also interested in it too.

Also, it's a feature supported in Ogre 1.x, so supporting it (even as an optional feature) will make upgraders happier.

BTW: I was trying to do something similar mentioned above (render two passes for different visibility masks), but failed. I don't know why, but even if I do this:

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render_scene
{
  overlay off
  visibility_mask 0x0
// shadows DefaultShadowNode
}

render_scene
{
  overlay off
// shadows DefaultShadowNode
}

The scene becomes very dark (well, not black because we have PCC and Irradiance Volumes enabled, but turning them off yield a completely black screen). Note that the shadow nodes are commented out. If I enable them, the scene will not be dark, but still can't achieve what I want.

However, if I do this as normal:

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render_scene
{
  overlay off
  shadows DefaultShadowNode
}

Everything's fine now.

I debugged a bit and found the viewport's visiblity mask is correctly set before each frustum cull, But it's too difficult to inspect what items/lights are culled, with watches in VS, and I didn't have time to inspect what data are sent to GPU by RenderDoc. I just feel that something screwed up

But if you can support lightmasks in Forward+, I don't have to bother this anymore in near future.

[dark_sylinc]

The scene becomes very dark (well, not black because we have PCC and Irradiance Volumes enabled, but turning them off yield a completely black screen). Note that the shadow nodes are commented out. If I enable them, the scene will not be dark, but still can't achieve what I want.

You've found a bug. Ogre is trying to reuse the culling results from the previous pass when it shouldn't.
I'll fix that one tomorrow along with adding per pixel shader visibility mask.

Edit: That bug is fixed.
Now I'm onto the fine granularity control.

[dark_sylinc]

Fine granularity got implemented for all RenderSystems.

It must be enabled via CMake variable OGRE_CONFIG_ENABLE_FINE_LIGHT_MASK_GRANULARITY to avoid penalizing other Ogre users for a feature they won't use. Once Ogre is compiled with that setting, it can be toggled via ForwardPlusBase::setFineLightMaskGranularity (which will be enabled by default).

Once enabled, Forward+ lights will only lit an object if the comparison "Light::getLightMask & MovableObject::getLightMask" returns non zero.

Normally it's a performance loss, but if the number of lights skipped via light mask has low divergence and covers a high number of pixels, it may improve performance. But most likely if you're using this feature you're more worried about aesthetics.
Though if coarse masking is enough for you, skipping lights via multiple scene passes and light_visibility_mask will be much faster. Note that coarse masking looks at getVisibilityFlags, while fine masking looks at getLightMask!

[rujialiu]

Fine granularity got implemented for all RenderSystems.

We've tried the fine granularity one. It works perfectly for us with both D3D11 and Metal. Thanks!