floor reflection in game engine

gamenoob

Hi,
I am trying to make a floor reflective. My implementation will be like the snapshot.



You can see the reflection on floor. How do I make a cube map to achieve scene like that? I mean where my camera will be and other additional things. Is this scene even achievable with cube map? I have never implement such thing before:(. Could anyone help me in this regards?

ZacD

A cube map is not ideal for a reflective floor, what game engine are you using?

gamenoob

I am using unity free version. How could I manage reflection then? It is not realtime reflection. I mean,the player and other moving stuff will not be seen on reflection. From the license note,I guess realtime reflection is not supported on free version. I can not afford pro version now. I have maya however.

pior

The old school trick is to simply flip the whole scene down, and set the floor plane to be as transparent as the desired amount of reflection

It's dirty and dumb but it sure works !

ZacD

A really cheap and old school way to do it is to duplicate and invert the geometry, and make the ground ground semi transparent, I've seen this used on mobile games as well. I'm not sure what reflection tools unity has, I have not used it much, but this unity demo uses the technique I was talking about for the water reflections http://u3d.as/content/unity-technologies/penelope-complete-project/1qZ


EDIT: Damn pior beat me to it, I was busy finding a image to use as an example, but that unity scene should work just as well, if not better, to showing how well it works.

gamenoob

hmm,thats a good trick,pior. Thanks. Though I am not sure about performance hit as we are doubling the whole scene. combining the flipped meshes as one, could drop drawcall I guess. But texture will be blurry as we are combining all mesh as one. However,nice trick.I will try it.


However,I thought of another. importing the whole scene with "external lightmapper tool" into maya,then adding a skybox on maya, then render cubemap on maya. Then we pick the rendered cubemap on hdr or exr format and convert it into six image by some program. Then we create a cubemap on unity with those six images.Then,we can apply a reflection shader on unity and apply the created cubemap. how about this idea? Will it even work?

Xoliul

Cubemap won't work at all man. Cubemaps are reflections sources for a single point. They work for single objects, but not for a large flat surface like a floor

gamenoob

So,dynamic reflection and doubling geometry is the only solution for these type of reflections?

passerby

if your useing udk, and got dx11 running, you could use image based reflections, it takes a lot of manual setup but the results look great.


There is also the scene Capture reflect actor, which is meant for use on large flat objects.

just place the actor, scale it to the size of your floor, than create a 2d render target for it, than use that texture in your material.


here is a sample of the method holden made
[ame="http://www.youtube.com/watch?v=2XoheOgAfkg"]UDK Realtime Reflective Floor Material - YouTube[/ame]

gamenoob

I am using unity3d. I can not invest such time on switching game engine. I have to do it on unity free.

SimonT

I don't know if unity can handle this, but the reflections in Dead Space 3 were nice!

http://simonschreibt.blogspot.de/2013/03/dead-space-3-diffuse-reflections.html

o2car

Unless you have a static camera position, Mirrored Geo or some screen-space reflection is the way to go.

chriszuko

Google led me to this. Maybe this will help.

http://wiki.unity3d.com/index.php?title=MirrorReflection2

Brendan

chriszuko wrote: »

Google led me to this. Maybe this will help.

http://wiki.unity3d.com/index.php?title=MirrorReflection2

Requires Pro as it uses a rendertexture if I recall correctly.


Check out the shadowgun (I think) demo. For their rainy floor they had a cubemap reflection that was just sorta abstract highlights, but with a scrolling normal map and rain effects they could get away with it.

If that doesn't work, just mirror the geo. It's not that hard.

Eric Chadwick

You might check out box projected cubemap environment mapping
http://forum.unity3d.com/threads/113784-Has-any-one-experimented-with-Box-Projection-Correction-Environment-Mapping