How to write in RenderBuffer

Hi,

I want to write a float buffer in texture. It's ok for pack value in RGBA and a other Channel ( five channel because the value is not in ]1,0] ) but have a bad accuracy.
i can too write bytes into color32 but in shader the binary operator are for shader model 4.
And finally i have too many texture for encode float.
The last way is write into a rendertexture; Rendertexture support Float value.

And i try that :

http://docs.unity3d.com/Documentati...aphics.SetRenderTarget.html?from=RenderBuffer

Code (csharp):

1.     m_Texture = new RenderTexture( aSizeUpperPow2X, aSizeUpperPow2Y, 0, RenderTextureFormat.ARGBHalf ) ;
2.     m_Texture.wrapMode = TextureWrapMode.Clamp ;
3.     m_Texture.filterMode = FilterMode.Point ;
4.    
5.     RenderTexture.active = m_Texture ;
6.     var aColorRenderBuffer : RenderBuffer; // = m_Texture.colorBuffer ;
7.     aColorRenderBuffer.m_RenderTexture = m_Texture ;
8.     aColorRenderBuffer.m_BufferPtr.IntPtr( aBuffer ) ;
9.    
10.     Graphics.SetRenderTarget( aColorRenderBuffer, m_Texture.depthBuffer ) ;
11.    
12.     RenderTexture.active = null ;
13.  

The errors :

Can i change the protection level ?

[Unity 3.5.5f3 pro]

 

I don't understand what you're trying to do on lines 7 and 8. Can you elaborate? Normally you'd just pass m_Texture.colorBuffer to SetRenderTarget, or just pass m_Texture as the only argument to get the same effect.

 

I want to write my buffer in m_Texture.

I understand that :

First step : set the current RenderTexture

Code (csharp):

1.  
2.  RenderTexture.active = m_Texture ;
3.  

Second step : create a renderbuffer

Code (csharp):

1.  
2.  var aColorRenderBuffer : RenderBuffer;
3.  

Third step : fill the renderbuffer

Code (csharp):

1.  
2.     aColorRenderBuffer.m_RenderTexture = m_Texture ;
3.  
4.     aColorRenderBuffer.m_BufferPtr.IntPtr( aBuffer ) ;
5.  

fourth step : Draw in the current texture/m_Texture manually ( http://docs.unity3d.com/Documentation/ScriptReference/Graphics.SetRenderTarget.html )

Code (csharp):

1.  
2.     Graphics.SetRenderTarget( aColorRenderBuffer, m_Texture.depthBuffer ) ;
3.  

fifth step : Turn off the current RenderTexture

Code (csharp):

1.  
2.    RenderTexture.active = null ;
3.  

 

Is the third step trying to get the colorBuffer to point to different backing storage (aBuffer)? Why? Just pass your m_Texture to Graphics.SetRenderTarget, then do your rendering, and finally read the data out using m_Texture.colorBuffer.

If you really want to break through the protection and rewrite the private members then you can do it using reflection, but I doubt it will help as colorBuffer is probably just a read-only C# view of the underlying C++ model. You can make the view point to the wrong bit of memory, but the rendering doesn't use it anyway, that all happens in the C++ code and won't care where the C# view is pointing.

 

Thanks gfoot.

Now I have no idea for fill texture 2D RGBA_FLOAT...

 

So if you're using immediate mode to issue your rendering, you should be able to just do:

Code (csharp):

1.  
2. Graphics.SetRenderTarget(m_Texture);
3. GL.Clear(...whatever...);
4. // draw stuff
5.  
6. // later on, when the rendering is all done
7. RenderTarget.active = m_Texture;
8. m_2DTexture.ReadPixels(new Rect(0, 0, width, height), 0, 0);
9. RenderTagret.active = null;
10.  

This is just a sketch, a lot depends on what you're rendering (immediate mode, full screen quad, or selected meshes from a manually-controlled camera). I also don't know how much latency you should expect before being able to lock the render target for reading.

And of course there's a conversion taking place here if your render target is using half precision. I don't know what the cost is, nor whether it can be mitigated by matching the texture format to the render target format. Presumably ReadPixels is a GPU operation...

I haven't seen any really good documentation on what any of these functions do, though, nor examples of different types of off-screen rendering. Most of what I know has been figured out by experimentation and by reading other forum or answers posts... not the best way.

 

Sorry gfoot, my explains are bad ( my english too ) but i want that :
I read a file -> i extrat the float data -> convert to a Bufferfloat -> convert to a TextureFloat -> and finally the Cg shader use the float data from the texture.

I have the same conclusion. If i want to write some floatting point values in rendertexture, i should have draw a 3D reprensentation....and it's too ....

Conclusion :
You can't fill the RenderTexture's data with your buffers. You can use Texture2D.SetPixels with texture2D but there are no RGBA_FLOAT, RGBA_HALF..... )

Oneaday i use five channels for pack my floatting data in texture2D.... it's not perfect but it's only way in Unity.

[PS : For unity devs : your Encode/Uncode Float RGBA functions from UnityCG.cginc are wrong.... there 256 values in a channel and not 255. You can test ... divide by 256.0 it's more accuracy ]

 

Ah, I see, you're doing it the other way around. Yes, it sucks but it looks like you can't store floating point data in a Texture2D at present.