This crazy real time ambient occlusion

I saw this link on Aras' site to a demoscene that features real time ambient occlusion and a paper about it..

Heres the demo: http://www.youtube.com/watch?v=9AX8gNyrSWc

And paper: http://rgba.scenesp.org/iq/computer/articles/ssao/ssao.htm

As for how they generate the mesh in the demo I have no clue whatsoever but it looks awesome.

Anyway, now comes the inevitable question... Is this possible in unity? Seems like it should be not that hard. I did a little experiment and drew the depth of the scene on a cube in front of the camera.

I have some questions. Right now on LateUpdate I do a switcheroo of all the materials and the camera settings, then camera.Render();, then set everything back the way it was and place the RenderTexture on the cube.

How would one really approach this? It almost seems like it could be a full screen image effect. I tried at first to make a full screen pixel correct render texture but that didn't work, I got an error message when placing the render texture on the cube saying the dimensions were wrong or something, and I got garbage on the cube. Making it power of two using mipmaps fixed it.

From the screenshots I've seen it looks like it actually works, and the shader doesn't look extremely complex to make so this is exciting.

<excitement>

</excitement>

 

Reminds me of one of my favorite pieces...Gestalt... not realtime but uses similar fractal quaternion geometry.

Let me know Forest if you're getting fancy with realtime AO and quaternion fractal based race tracks... our race cars might need some modding to cope with this :wink:

Seriously though, any experiments on this front are very interesting.

Ethan

 

So you are saying with point 1 that simply encoding the depth into the render texture as the alpha channel or a color channel will not be precise enough? It seems one could also spread the depth out over a few channels to get more precision, but that just makes your depth shader and SSAO shader more complicated, right?

And point 3 I can understand, although I have never tested the limits of how long a fragment program can be. Is it a hard limit or specific to each card?

Maybe I shouldn't have been thinking about this so hard, cause now I'm really itching to try it out. I had some other ideas about how to improve it, like storing the "average depth" of each object in an unused channel in the render texture to help get rid of artifacts where you get a black line around things in the foreground.

(this problem seen in the bottom right project offset screenshot)

 

Its alive!

 

Awesome Yoggy.

I've been playing a bit with this too, the effect is too cool to stay away from. I already had the depthmap from my dof effect so I thought it would be easy. Haven't cracked it yet though. Good work

/Patrik

 

sweet yoggy - though what is causing the blotchy effect?

 

Ooh. The artifacts are actually rather pretty.

I'd guess he's not yet got to the "Second Trick" section here, which talks about banding:
http://rgba.scenesp.org/iq/computer/articles/ssao/ssao.htm

Cheers,
-Jon

 

Yeah I thought so too, jon. Looks like pencil shading sometimes

Its caused by depth buffer imprecision induced by the fact that I am only using 1 channel of a render texture to store the depth.

I am going to try to save up enough instructions to add noise too it too, which will probably help quite a bit. Then I've got to figure out the blur pass too.

Oh and patrik / anyone else who wants to have a look so far, heres a WIP package:

 

"The second trick"

 

just too cool - and I agree - the artifacts actually add to it, kill the CG ness by making it gritty, sorta like sharcoal - wonder if you can make it look like watercolor or clay too

 

Its coming along quite nicely, I added some interactivity to showcase it's realtimeness.

Just need to figure out the blur now.

http://yogware.bluegillstudios.com/SSAO/SSAO.html

Edit: The shader isn't working in the webplayer here.. Oh well, I need to sleep...

 

hi Yoggy

Just wanted to let you know its working in the webplayer here on my pc:
windows xp sp2
explorer 7
geforce 8800 gts 320mb
2 gb ram

Also; thats bloody amazing! I remember being in awe when I saw a demonstration of CryEngine2 that included realtime AO and now Unity has it too. Thats just soo cool!

Congrats on your smartness

 

Yoggy that is stunning. I also agree the rougher dotted artifacts really help get rid of that too clean computer generated look, but the web player is magnificant. I want one
A question which is way too early to ask - could this be applied to the terrain stuff so that trees and detail meshes look properly grounded?
Nice work
Boxy

 

Very cool Forest!

 

I download the SSAO.unityPackage and import this to a new scene, but I get blank screen when I run this!!

 

Amazing stuff, I really hope you continue the work and release an even more pulished version.

Just one question: it only works on Unity Pro, isn't it?

 

Really looking forward to updates on this .

I have a friend who runs a local games studio and he's working on a little xbla game and is using this kind of thing (AO is calculated in real time, while all his models etc mostly just have block colours on)

 

I get a blank screen when running it maximized, and non maximized it dosent seem to work :S

It does work in the webplayer tho on both my mac and pc.

When loading up the package in Unity I get the error "Cg in program "frag": error C6003: Arithmatic instruction limit of 64 exceeded; 70 arithmatic instructions needed to compile program at line 21."

 

Thats really cool.

To speed things up, couldn't you kinda bake any self AO or static AO?

Just an idea.

Keep it up.

Geoff

 

I see the same error here :?

<edit >
Tracing back through the error log, it seems the problem might be with munged line endings on the ScreenSpaceAO.js. Fixing that made the error go away.

However, I still too get only black after the thing starts. (Unity Pro here, too).

</edit>

really cool stuff though, wtg Yoggy -- just stumbled across this...

 

This seems like the way forward. Again, this is amazing.

 

Any news or updates on this Forest? Would love to see this developed further.

 

Bump. I would really like to see if we can get some sweet darkened scenes with this effect.

 

Same here. I tried to remove some iterations from the shader - errors disappeared, but there's no AO.

Does this only work on Unity Pro?

 

Updated version.

 

I've been hoping and asking for this for years...
I'd like to run the calculation once in the editor and cache the result.

Thanks!

 

Cgorgan: I think you'd be better off baking the AO for static objects in your scene into a texture map in your 3d graphics program, and use the AO shader for moving objects. :wink:

 

Hi,

I only get a black screen. Pressing the "c" switch key i can see the [normal] scene, then pressing "C" again i return to a black screen [no AO]. The aimer and all GUI objects are visible over the black scene.

This happens on Mac in Editor, WebPlayer and exported application.
I just try the WebPlayer on Windows : Crash at launch, IE or FF exits with no error.

Tests done with
MAC : Unity Pro 2.1.0f5 (16146) - MacIntel 10.4.11 RadeonX1600
WIN : XP pro SP2 - GeForce 8500 GT (IE Firefox [same result]) :wink:

Btw Forest this is an amazing work. Thanks

 

I'm not sure that would work. My impression was that it's a full-screen effect. Even if each X and O had its own self-occlusion map, it would still need to check each pixel of each X and O the image to see if it occluded something else... right? You'd basically be adding a bunch of textures to the render pipeline but not taking anything off of it, since each pixel needs to be calculated.

It would be like baking your lights to your scene via a script in Unity... and then not deleting these lights because you want to take advantage of bump-mapping on the baked object. Right? Unless I'm missing something... please correct me if I'm wrong!

 

I have no idea, i'm more artist than programmer but when watching the demo noticed that quite a lot of the realtime AO never changes so suggested it could be baked, ignored or something. As to the how...well thats for somebody else to work out

Geoff

 

the webplayer works fine on both systems here and fast as well

82FPS on my MacBookPro 8600M GT 256MB, OSX 10.5.6
280FPS on my Vista64 Desktop, core i7 920, GTX280

 

Yeah of course you can back it into the scene. But that would mean you would have to know your exact scene set up out side of unity. also you could not add prefabs to your scene or other objects and have the lighting match easily. I'd like to see it as an option. It would be really handy.

-Realtime
-first frame only
-baked in editor

 

I think the baking is also an issue when you come to having a bunch of moving items in the scene. This is definitely a work in progress but its very impressive nonetheless.

 

cool stuff indeed! (if i only could get it to work ) i also get a black screen when i hit C, so any suggestions to what the problem might be are very welcome!

btw. macbook pro/8600GT 512 / OSX 10.5.5

 

Are you using pro?

 

Yup! Please enlighten me anyone

 

If it helps, I see the same exact behavior here (also, line ending errors, and deprecated methods in MouseLook, as pre v2.0).

The textured version of this scene looks nice, would love to see it with this AO implementation!

Using Unity Pro on latest Macbook Pro (of this writing).

 

I'm having the same issue with the black screen (on a Macbook Pro).

 

You can't do this with SSAO at all.
As the name says, it is SCREEN SPACE Ambient Occlusion.
This means that it is calculated on SCREEN SPACE.
So just imagine that it is NOT calculated for the 50% of polygons that are on the side opposite to your point of view (to tell it short).
This said, if you want to bake lighting on your objects, once you are "trashing" lot of memory for static litghint, better do it for good and put in it radiosity, final gather, AO, ect.

 

Very cool!

We're not far from convincing approximations of physically accurate lighting in real time. For example, this renders at 15-20 fps (on the right hardware

http://graphics.cs.umass.edu/pubs/srt/

(watch the video, it's great)

 

You can do this with blender.

 

Hello everyone, A good start this is,
i've been interested in an ambient occlusion shader myself, for the record i'm an artist and not a programmer.

perhaps i can point you towards a direction you might want to consider as well, now visualy an ambient occlusion adds alot, and i consider it a must have in any creation. however you got a couple of things to consider here both performance wise and visual/control, lets say you got this level full of objects cmodels stuff all over, adding a realtime AO all over this will drasticly slow things down not to mention the shaders/lights that will be acting on top of all this, now if you had an engine like crysis this may not be a problem, but lets stay realistic here with the tools we've got and try to make the best out of them.. i suggest to focus on couple of things here, and those things are the moving object(s) in your scene , and ONLY the moving objects, this would be the characters lets say most of the time which are the center of the players attention.
have the entire other static objects baked with AO in a software like blender /max etc. which give you more control over the look, and even have your characters static mesh baked with AO as well, when you place your character in the engine along with the scene everything will match up with the exception of one thing, only major visible problem here is that the characters feet lets say do not interact with the floor AO wise , now the trick part comes in on how to get a second layer of AO or any other similar trick only the character in order for it to create that gap of an illusion of its interaction with the environment.

But then again this is only a suggestion if it makes life any easier for you, if you can get the whole thing working then thats great. and best of luck!

keep up the great work guys!

 

All it has to do is bake one frame for the entire scene. :]

Make it an editor plugin maybe?

 

adding this line:

Code (csharp):

1. #pragma target 3.0

to the ssao shader did the job... at least for me.

lars

Code (csharp):

1.  
2. Shader "SSAO" {
3. Properties {
4.     _MainTex ("Texture", 2D) = "white" { }
5.     _NoiseTex ("Texture", 2D) = "white" { }
6. }
7. SubShader {
8.     // First pass called with Material.SetPass(), draw opaque to clear the render texture
9.     Pass {
10.         CGPROGRAM
11.             #pragma target 3.0
12.             #pragma vertex vert
13.             #pragma fragment frag
14.             #pragma fragmentoption ARB_fog_exp2
15.             #pragma fragmentoption ARB_precision_hint_nicest
16.             #include "SSAO.cginc"
17.         ENDCG
18.     }
19.    
20.     // Called with Material.SetPass() for all passes after the first, multiply the result into the texture
21.     Pass {
22.         Blend DstColor Zero
23.         CGPROGRAM
24.         #pragma target 3.0
25.             #pragma vertex vert
26.             #pragma fragment frag
27.             #pragma fragmentoption ARB_fog_exp2
28.             #pragma fragmentoption ARB_precision_hint_nicest
29.             #include "SSAO.cginc"
30.         ENDCG
31.     }
32. }
33. Fallback "VertexLit"
34. }
35.  

 

Black Screen here too : Unity v2.5 Widows Vista Ultimate : Unity PRO

 

Got it working by following post about adding

#pragma target 3.0

to the SSAO shader

 

i'm having problems importing the package into unity. error says unity couldnt decompress the package.

and as per the posted code above, there's an ssao.cginc include file needed. where can i get this?

am i missing doing something.

 

a forest i think ur blend files are corrupted or something in this ssao package. my unity crashes every time it gets to bringing in the room.blend file. Also when i try to reopen the files after i have close down unity it freezes up unless i delete the blend files.