Horde3D

I want to be able to write to the depth buffer and have it act as if I where rendering a normal object. However I wish for it not to look at the depth buffer when actually rendering the objects.

I want to do this so as I can render particles and use deferred shading, I know that it would be possible to do this using two pass's of my particle system. One with the depth testing on and one with it off, but I feel that this is very wasteful and hope there is a method which could allow me to do it in a single pass.

If there is a better method of rendering particles and other translucent objects with deferred shading I would like to know.

Thank you

I don't quite understand your question there - you want to write to the depth buffer, but turn off depth testing? That isn't hard, but it doesn't sound quite like what you are asking. Also beware that particles will appear that should be behind other objects.

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Tristam MacDonald - [swiftcoding]

From what I understand of what he's upto at the moment... basically he wants to use it like a temporary buffer and write information to it, but only read it from another buffer, rather than the screen.

Not sure if that makes it sound much clearer, hehe

You can attach a depth buffer to a render target, and then bind it as a texture during another pipeline stage, certainly - I do this for atmosphere rendering.

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Tristam MacDonald - [swiftcoding]

As swiftcoder already states it's no problem to use a depth buffer as render target. I have already done this for an ssao test some months ago.

Yes I have the same render target being used, it is just that it takes two pass's for both the graphical data and depth data to be used as when you set writeDepth="true" this also results in it using the depth buffering when rendering.


is what my pipeline looks like at present, the TRANSLUCENT context is the same as from the examples and the TRANSLUCENT_DEPTH simply does nothing in the fragment shader but has writeDepth="true". This render context then gets combined with the screen buffer using a fragment shader to test its depth values against the GBUFFER. This works but seems wasteful having to 'render' all the particles twice

I am pretty sure that that gives no advantage over rendering once, with depth writes on. Why exactly do you not want depth testing enabled when rendering the particles? That said, there should be a way to turn off just the depth test, but I don't know a horde option for it offhand.

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Tristam MacDonald - [swiftcoding]

I want depth testing turned on when rendering them over the rest of the scene so as the particles behind walls, floors etc will not be rendered but those in front will but will also take into account alpha blending

So you want to turn depth writes off when rendering the blend? Is it really necessary? If you leave depth writes on, you have the depth buffer filled out for your next pass. You may have a few artifacts due to incorrect ordering, but it is probably worth taking a look to see how obvious they are.

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Tristam MacDonald - [swiftcoding]

Lachlan, I still don't quite understand what eactly you want to do. But one thing I'm aware of that is still missing is a shader param to configure the depth test (not mask).