Textures mix up... blurX and then blurY?

DerWoDaSo · July 28, 2009, 7:33pm

Hey!

I want to blur a rendered image. Somehow it works and somehow not. Here is what (I think) I do:

Blur the image from the camera horizontal (with the first pass of a shader).
Blur the result of 1. vertical (with the second pass of a shader).
return the result to a rendertexture.

But the result seems to be…

returns a black image (??)
returns a vertical blurred image from the camera (ignore input from 1.)

A few minutes ago I suddenly had a normal map from the mesh the camera is rendering in the resulting texture? Somehow the textures seem to mix up…

The C# code:

void OnRenderImage(RenderTexture source, RenderTexture dest)
{
    RenderTexture blurUBuffer = RenderTexture.GetTemporary(512, 512, 0);
    RenderTexture blurVBuffer = RenderTexture.GetTemporary(512, 512, 0);
	
	//blur horizontal
    blurDirectional(source, blurUBuffer, true); 
    
    //blur vertical
    blurDirectional(blurUBuffer, blurVBuffer, false);

    ImageEffects.Blit(blurVBuffer, dest);

    blurUBuffer.Release();
    blurVBuffer.Release();
}

private void blurDirectional(RenderTexture blurSource, RenderTexture blurDest, bool direction)
{
    RenderTexture.active = blurDest;

    float offset = 1.0f / (float)blurSource.width;
    
    GL.PushMatrix();
    GL.LoadOrtho();

    //first pass: horizontal blur
    //second pass: vertical blur
    blurMaterial.SetPass(direction ? 0 : 1);
    
    blurMaterial.SetFloat("_Offset", offset);
    blurMaterial.SetTexture("_SourceTex", blurSource);

    RenderQuad();
    
    GL.PopMatrix();
}

private void RenderQuad()
{
    GL.Begin(GL.QUADS);
    GL.TexCoord2(0.0f, 0.0f); GL.Vertex3(-1.0f, -1.0f, 0.1f);
    GL.TexCoord2(1.0f, 0.0f); GL.Vertex3(1.0f, -1.0f, 0.1f);
    GL.TexCoord2(1.0f, 1.0f); GL.Vertex3(1.0f, 1.0f, 0.1f);
    GL.TexCoord2(0.0f, 1.0f); GL.Vertex3(-1.0f, 1.0f, 0.1f);
    GL.End(); 
}

Any major mistake here?

The blur shader basically only gets 5 weighted samples in one direction (one in each pass) and returns the sum.

Is it correct, that for a RenderTexture I need a texRECT sampler and for a normal Texture2D a tex2D sampler?

DerWoDaSo · July 31, 2009, 4:23pm

Nobody any idea? What could be the reason that if I render an effect twice, it works only once (but there perfectly).

Even if I use a shader that just passes one sample of the input texture.

  blurDirectional(blurUBuffer, blurVBuffer, false); //works fine
  blurDirectional(blurVBuffer, blurUBuffer, false); // mixes up textures, renders black textures,...

It drives me crazy… [/code]

DerWoDaSo · August 5, 2009, 2:51pm

Ok… here is a small demo which demonstrates my problem:

http://www.janbubenik.de/da/demos/renderTextureDemo.html

The scene consists of a sphere (turning), 2 directional lights and a camera with the following script:

using UnityEngine;
using System.Collections;

public class TestRenderToTexture : MonoBehaviour {

    public int size = 512;

    public int iterations = 1;

    private string debugString = "";
    private bool releaseTemp = true;

    private static string myMatString =
@"Shader ""SSS/testCopyShader"" {
	SubShader {
		Pass {
			ZTest Always Cull Off ZWrite Off Fog { Mode Off }
			SetTexture [__RenderTex] {constantColor (0.8,0.8,1,1) combine texture * constant}
		}
	}
	Fallback off
}";

    protected Material myMaterial = null;
    protected Material getMaterial
    {
        get
        {
            if (myMaterial == null)
            {
                myMaterial = new Material(myMatString);
                myMaterial.hideFlags = HideFlags.HideAndDontSave;
                myMaterial.shader.hideFlags = HideFlags.HideAndDontSave;
            }
            return myMaterial;
        }
    }

    void OnRenderImage(RenderTexture source, RenderTexture dest)
    {
        debugString = "";
        
        if (iterations > 0)
        {
            RenderTexture tempBuffer1 = RenderTexture.GetTemporary(size, size, 0);
            RenderTexture tempBuffer2 = RenderTexture.GetTemporary(size, size, 0);
            debugString += "-> GetTemporary temp1  temp2\n";

            bool oddEven = true;

            copyTexture(source, tempBuffer1);
            debugString += "copy(source, temp1)\n";

            for (int i = 0; i < iterations-1; i++)
            {
                if (oddEven)
                {
                    copyTexture(tempBuffer1, tempBuffer2);
                    debugString += "copy(temp1, temp2)\n";
                }
                else
                {
                    copyTexture(tempBuffer2, tempBuffer1);
                    debugString += "copy(temp2, temp1)\n";
                }
                oddEven = !oddEven;
            }

            if (oddEven)
            {
                copyTexture(tempBuffer1, dest);
                debugString += "copy(temp1, dest)\n";
            }
            else
            {
                copyTexture(tempBuffer2, dest);
                debugString += "copy(temp2, dest)\n";
            }

            if (releaseTemp)
            {
                tempBuffer1.Release();
                tempBuffer2.Release();
                debugString += "-> Release temp1  temp2\n";
            }

            if (iterations > 10)
            {
                int start = 122;
                int end = 238;
                if (!releaseTemp)
                    end -= 3;
                debugString = debugString.Remove(start, debugString.Length - end);
                debugString = debugString.Insert(start, "\n[...]\n");
            }
        }
        else
        {
            copyTexture(source, dest);
            debugString += "\ncopy(source, dest)\n\n";
        }
    }
    
    private void copyTexture(RenderTexture source, RenderTexture dest)
    {
        RenderTexture.active = dest;

        GL.PushMatrix();
        GL.LoadOrtho();

        getMaterial.SetPass(0);

        source.SetGlobalShaderProperty("__RenderTex");

        RenderQuad();

        GL.PopMatrix();
    }

    private void RenderQuad()
    {
        GL.Begin(GL.QUADS);
        GL.TexCoord2(0.0f, 0.0f); GL.Vertex3(0.0f, 0.0f, 0.1f);
        GL.TexCoord2(1.0f, 0.0f); GL.Vertex3(1.0f, 0.0f, 0.1f);
        GL.TexCoord2(1.0f, 1.0f); GL.Vertex3(1.0f, 1.0f, 0.1f);
        GL.TexCoord2(0.0f, 1.0f); GL.Vertex3(0.0f, 1.0f, 0.1f);
        GL.End();
    }

    void OnGUI()
    {
        GUI.Label(new Rect(5, 5, 200, 200), debugString);
        GUI.Label(new Rect(45, Screen.height - 30, 80, 25), "iterations: " + iterations.ToString());
        if (GUI.Button(new Rect(5, Screen.height - 30, 30, 25), "+"))
        {
            iterations++;
            if (iterations > 100)
                iterations = 100;
        }
        if (GUI.Button(new Rect(125, Screen.height - 30, 30, 25), "-"))
        {
            iterations--;
            if (iterations < 0)
                iterations = 0;
        }
        if (GUI.Button(new Rect(165, Screen.height - 30, 100, 25), "release: " + releaseTemp.ToString()))
            releaseTemp = !releaseTemp;
    }
}

anon_28479189 · August 5, 2009, 7:41pm

in your blur code isnt any texture offset niether in shader or in texture coord generation.

and that is why you simply copy texture pixel by pixel all passes.

DerWoDaSo · August 5, 2009, 8:42pm

Oh, sorry… I should have mentioned, that I do this on purpose.

I removed the blur itself, because I already get the error when simply copying the texture (like you said). I am trying to simplify the whole thing to track down the problem.

If you open that link you will see a ball spinning around. If you click on “+” at the bottem-left you will increase the iteration-steps. With “Release” turned on, every second iteration-step will display the base texture of the sphere… and I really don’t know why!

DerWoDaSo · August 6, 2009, 11:53am

Alright… I got it. The error was right here:

GL.PushMatrix();
GL.LoadOrtho();
[..]
source.SetGlobalShaderProperty("__RenderTex");

You can’t set the ShaderProperty after these GL commands.

This way it works:

[..]
source.SetGlobalShaderProperty("__RenderTex");

GL.PushMatrix();
GL.LoadOrtho();

the_gnoblin · August 6, 2009, 12:09pm

I suppose writing _RenderTex instead of __RenderTex won’t do much difference?

Also I think it is better to blur image in horizontal direction, then blur original image in vertical direction and then combine the two results.

DerWoDaSo · August 6, 2009, 12:30pm

__RenderTex or _RenderTex doesn’t make a difference.

But you have to blur the horizontal blured image vertical (not the original one).

This would be the difference:

182881--6493--$blur_707.jpg

DerWoDaSo · August 8, 2009, 10:26am

Here’s the result so far… on the left without diffuse texture and on the right with diffuseTex multiplied.

The skin still needs a lot of tweaking. The blue edges in the left image can be removed with a proper gamma correction. At the moment I am working on that.

Not an easy topic… sRGB textures aren’t supported, right? Floating point RTs neither… too bad.

anon_47180401 · December 30, 2009, 5:24pm

Hello DerWoDaSo,

I tested your blur and the result I get is just a blue image. The more iterations I do the blued I see the image. Is that normal? What could I change to see a blurred result instead of a change of color?

DerWoDaSo · December 31, 2009, 10:10am

Hey Babur, the problem is, there is no “blur shader” in here at the moment… I used a simple replacement for debugging and to demonstrate the problem.

@"Shader ""SSS/testCopyShader"" {
   SubShader {
      Pass {
         ZTest Always Cull Off ZWrite Off Fog { Mode Off }
         SetTexture [__RenderTex] {constantColor (0.8,0.8,1,1) combine texture * constant}
      }
   }
}

You need a shader that performs a separable gaussian blur. But I don’t have the code here right now… sorry. I will try to update my blog soon with some code examples, but I am pretty busy right now.

anon_47180401 · December 31, 2009, 10:14am

Oooups ok thanks anyway It seems that the Wii does not support shaders anyway so I would need to do this on script. I don’t know if there are any tools to modify texture pixels directly from script. I will have to investigate :roll:

DerWoDaSo · December 31, 2009, 10:32am

Oh… well, I don’t think that’s possible. You CAN read pixel values from script (see Script Reference - GetPixel), but it will be SLLOOOOOW.

anon_47180401 · December 31, 2009, 10:37am

Damn! I was having a look at that right now… but I don’t get why this function should be slow… a texture is a simple 2D array… or am I wrong?

llde_chris · January 5, 2010, 2:04am

A texture is just a 2D array… that gets written to and read from the graphics card.

Reading the texture out of the graphics card is slow.

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