commit 664a0e455c85ae80ea270f5fabe39a416f6614cd
Author: Leszek Koltunski <leszek@koltunski.pl>
Date:   Wed Apr 11 23:56:49 2018 +0100

    New app checking Order Independent Transparency.

diff --git a/src/main/AndroidManifest.xml b/src/main/AndroidManifest.xml
index 849c8c2..ae762fb 100644
--- a/src/main/AndroidManifest.xml
+++ b/src/main/AndroidManifest.xml
@@ -46,6 +46,7 @@
         <activity android:name=".blur.BlurActivity"/>
         <activity android:name=".multiblur.MultiblurActivity"/>
         <activity android:name=".triblur.TriblurActivity"/>
+        <activity android:name=".transparency.TransparencyActivity"/>
         <activity android:name=".postprocesstree.PostprocessTreeActivity"/>
         <activity android:name=".stencil.StencilActivity"/>
         <activity android:name=".glow.GlowActivity"/>
diff --git a/src/main/java/org/distorted/examples/TableOfContents.java b/src/main/java/org/distorted/examples/TableOfContents.java
index e7741eb..45f477d 100644
--- a/src/main/java/org/distorted/examples/TableOfContents.java
+++ b/src/main/java/org/distorted/examples/TableOfContents.java
@@ -64,6 +64,7 @@ import org.distorted.examples.mirror.MirrorActivity;
 import org.distorted.examples.blur.BlurActivity;
 import org.distorted.examples.multiblur.MultiblurActivity;
 import org.distorted.examples.triblur.TriblurActivity;
+import org.distorted.examples.transparency.TransparencyActivity;
 import org.distorted.examples.postprocesstree.PostprocessTreeActivity;
 import org.distorted.examples.stencil.StencilActivity;
 import org.distorted.examples.glow.GlowActivity;
@@ -360,6 +361,15 @@ public class TableOfContents extends ListActivity
       activityMapping.put(i++, TriblurActivity.class);
    }
 
+   {
+      final Map<String, Object> item = new HashMap<>();
+      item.put(ITEM_IMAGE, R.drawable.icon_example_transparency);
+      item.put(ITEM_TITLE, (i+1)+". "+getText(R.string.example_transparency));
+      item.put(ITEM_SUBTITLE, getText(R.string.example_transparency_subtitle));
+      data.add(item);
+      activityMapping.put(i++, TransparencyActivity.class);
+   }
+
    {
       final Map<String, Object> item = new HashMap<>();
       item.put(ITEM_IMAGE, R.drawable.icon_example_postprocesstree);
diff --git a/src/main/java/org/distorted/examples/transparency/TransparencyActivity.java b/src/main/java/org/distorted/examples/transparency/TransparencyActivity.java
new file mode 100644
index 0000000..d8cedf4
--- /dev/null
+++ b/src/main/java/org/distorted/examples/transparency/TransparencyActivity.java
@@ -0,0 +1,153 @@
+///////////////////////////////////////////////////////////////////////////////////////////////////
+// Copyright 2016 Leszek Koltunski                                                               //
+//                                                                                               //
+// This file is part of Distorted.                                                               //
+//                                                                                               //
+// Distorted is free software: you can redistribute it and/or modify                             //
+// it under the terms of the GNU General Public License as published by                          //
+// the Free Software Foundation, either version 2 of the License, or                             //
+// (at your option) any later version.                                                           //
+//                                                                                               //
+// Distorted is distributed in the hope that it will be useful,                                  //
+// but WITHOUT ANY WARRANTY; without even the implied warranty of                                //
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                                 //
+// GNU General Public License for more details.                                                  //
+//                                                                                               //
+// You should have received a copy of the GNU General Public License                             //
+// along with Distorted.  If not, see <http://www.gnu.org/licenses/>.                            //
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+package org.distorted.examples.transparency;
+
+import android.app.Activity;
+import android.opengl.GLSurfaceView;
+import android.os.Bundle;
+import android.view.View;
+import android.widget.SeekBar;
+
+import org.distorted.examples.R;
+import org.distorted.library.main.Distorted;
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+public class TransparencyActivity extends Activity implements SeekBar.OnSeekBarChangeListener
+{
+    private int mRenderFirst;
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    @Override
+    protected void onCreate(Bundle savedState) 
+      {
+      super.onCreate(savedState);
+      setContentView(R.layout.transparencylayout);
+
+      SeekBar barRed    = (SeekBar)findViewById(R.id.transparencySeekRed);
+      SeekBar barYellow = (SeekBar)findViewById(R.id.transparencySeekYellow);
+
+      barRed.setOnSeekBarChangeListener(this);
+      barYellow.setOnSeekBarChangeListener(this);
+
+      if( savedState==null )
+        {
+        barRed.setProgress(50);
+        barYellow.setProgress(50);
+        privateRenderFirst(0);
+        }
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+    
+    @Override
+    protected void onPause() 
+      {
+      GLSurfaceView view = (GLSurfaceView) this.findViewById(R.id.transparencySurfaceView);
+      view.onPause();
+      Distorted.onPause();
+      super.onPause();
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+    
+    @Override
+    protected void onResume() 
+      {
+      super.onResume();
+      GLSurfaceView view = (GLSurfaceView) this.findViewById(R.id.transparencySurfaceView);
+      view.onResume();
+      }
+    
+///////////////////////////////////////////////////////////////////////////////////////////////////
+    
+    @Override
+    protected void onDestroy() 
+      {
+      Distorted.onDestroy();  
+      super.onDestroy();
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    @Override
+    public void onSaveInstanceState(Bundle savedInstanceState)
+      {
+      super.onSaveInstanceState(savedInstanceState);
+      savedInstanceState.putInt("render", mRenderFirst);
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    @Override
+    public void onRestoreInstanceState(Bundle savedInstanceState)
+      {
+      super.onRestoreInstanceState(savedInstanceState);
+
+      mRenderFirst= savedInstanceState.getInt("render");
+      privateRenderFirst(mRenderFirst);
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    public void onProgressChanged(SeekBar bar, int progress, boolean fromUser)
+      {
+      switch (bar.getId())
+        {
+        case R.id.transparencySeekRed:    TransparencySurfaceView view0 = (TransparencySurfaceView) this.findViewById(R.id.transparencySurfaceView);
+                                          view0.getRenderer().setTransparency(0, (float)progress/100 );
+                                          break;
+        case R.id.transparencySeekYellow: TransparencySurfaceView view1 = (TransparencySurfaceView) this.findViewById(R.id.transparencySurfaceView);
+                                          view1.getRenderer().setTransparency(1, (float)progress/100 );
+                                          break;
+        }
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    public void onStartTrackingTouch(SeekBar bar) { }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    public void onStopTrackingTouch(SeekBar bar)  { }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    public void renderFirst(View v)
+      {
+      switch(v.getId())
+        {
+        case R.id.transparencyRed   : privateRenderFirst(0); break;
+        case R.id.transparencyYellow: privateRenderFirst(1); break;
+        }
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    private void privateRenderFirst(int index)
+      {
+      TransparencySurfaceView view = (TransparencySurfaceView) this.findViewById(R.id.transparencySurfaceView);
+      TransparencyRenderer renderer= view.getRenderer();
+
+      renderer.setRenderFirst(index);
+      mRenderFirst = index;
+      }
+}
diff --git a/src/main/java/org/distorted/examples/transparency/TransparencyRenderer.java b/src/main/java/org/distorted/examples/transparency/TransparencyRenderer.java
new file mode 100644
index 0000000..aab6a78
--- /dev/null
+++ b/src/main/java/org/distorted/examples/transparency/TransparencyRenderer.java
@@ -0,0 +1,200 @@
+///////////////////////////////////////////////////////////////////////////////////////////////////
+// Copyright 2016 Leszek Koltunski                                                               //
+//                                                                                               //
+// This file is part of Distorted.                                                               //
+//                                                                                               //
+// Distorted is free software: you can redistribute it and/or modify                             //
+// it under the terms of the GNU General Public License as published by                          //
+// the Free Software Foundation, either version 2 of the License, or                             //
+// (at your option) any later version.                                                           //
+//                                                                                               //
+// Distorted is distributed in the hope that it will be useful,                                  //
+// but WITHOUT ANY WARRANTY; without even the implied warranty of                                //
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                                 //
+// GNU General Public License for more details.                                                  //
+//                                                                                               //
+// You should have received a copy of the GNU General Public License                             //
+// along with Distorted.  If not, see <http://www.gnu.org/licenses/>.                            //
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+package org.distorted.examples.transparency;
+
+import android.opengl.GLSurfaceView;
+
+import org.distorted.library.effect.FragmentEffectAlpha;
+import org.distorted.library.effect.MatrixEffectMove;
+import org.distorted.library.effect.MatrixEffectQuaternion;
+import org.distorted.library.effect.MatrixEffectScale;
+import org.distorted.library.effect.PostprocessEffectBlur;
+import org.distorted.library.main.Distorted;
+import org.distorted.library.main.DistortedEffects;
+import org.distorted.library.main.DistortedNode;
+import org.distorted.library.main.DistortedScreen;
+import org.distorted.library.main.DistortedTexture;
+import org.distorted.library.main.MeshFlat;
+import org.distorted.library.type.Static1D;
+import org.distorted.library.type.Static3D;
+import org.distorted.library.type.Static4D;
+
+import javax.microedition.khronos.egl.EGLConfig;
+import javax.microedition.khronos.opengles.GL10;
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+class TransparencyRenderer implements GLSurfaceView.Renderer
+{
+    private static final int NUM = 4; // 4 ints (x,y,z, argb) each describe 1 object below
+
+    private static final int[] OBJECTS =
+        {
+         +9, -10, +2, 0xffff0000,
+         -9, +10, -2, 0xffffff00
+        };
+
+    private static final int NUM_OBJECTS = OBJECTS.length/NUM;
+    private static final int OBJ_SIZE    = 100;
+
+    private GLSurfaceView mView;
+    private DistortedNode[] mNode;
+    private DistortedTexture[] mTex;
+    private Static3D[]  mMoveVector;
+    private Static1D[]  mAlphaVector;
+    private DistortedScreen mScreen;
+    private Static3D mMove, mScale, mCenter;
+
+    Static4D mQuat1, mQuat2;
+    int mScreenMin;
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    TransparencyRenderer(GLSurfaceView v)
+      {
+      mView = v;
+
+      MeshFlat mesh = new MeshFlat(1,1);
+
+      mQuat1 = new Static4D(0,0,0,1);  // unity
+      mQuat2 = new Static4D(0,0,0,1);  // quaternions
+
+      mScreen = new DistortedScreen();
+      mScreen.glClearColor(1.0f,1.0f,1.0f,1.0f);
+
+      mMoveVector   = new Static3D[NUM_OBJECTS];
+      mAlphaVector  = new Static1D[NUM_OBJECTS];
+      mNode         = new DistortedNode[NUM_OBJECTS];
+      mTex          = new DistortedTexture[NUM_OBJECTS];
+
+      FragmentEffectAlpha[] alpha= new FragmentEffectAlpha[NUM_OBJECTS];
+      DistortedEffects[] effects = new DistortedEffects[NUM_OBJECTS];
+
+      mMove  = new Static3D(0,0,0);
+      mScale = new Static3D(1.0f,1.0f,1.0f);
+      mCenter= new Static3D(0,0,0);
+
+      MatrixEffectMove moveEffect        = new MatrixEffectMove(mMove);
+      MatrixEffectScale scaleEffect      = new MatrixEffectScale(mScale);
+      MatrixEffectQuaternion quatEffect1 = new MatrixEffectQuaternion(mQuat1, mCenter);
+      MatrixEffectQuaternion quatEffect2 = new MatrixEffectQuaternion(mQuat2, mCenter);
+
+      PostprocessEffectBlur blur = new PostprocessEffectBlur(new Static1D(0));
+
+      for(int i=0; i<NUM_OBJECTS; i++)
+        {
+        mTex[i]           = new DistortedTexture(OBJ_SIZE,OBJ_SIZE);
+        mMoveVector[i]   = new Static3D(0,0,0);
+        mAlphaVector[i]  = new Static1D(0.5f);
+        alpha[i]         = new FragmentEffectAlpha(mAlphaVector[i]);
+        effects[i]       = new DistortedEffects();
+
+        //effects[i].apply(blur);
+        effects[i].apply(alpha[i]);
+        effects[i].apply(moveEffect);
+        effects[i].apply(scaleEffect);
+        effects[i].apply(quatEffect1);
+        effects[i].apply(quatEffect2);
+        effects[i].apply(new MatrixEffectMove(mMoveVector[i]));
+
+        mNode[i] = new DistortedNode(mTex[i], effects[i], mesh );
+        mScreen.attach(mNode[i]);
+        }
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    void setTransparency(int object, float level)
+      {
+      if( object>=0 && object<NUM_OBJECTS) mAlphaVector[object].set(level);
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+// no better way to attach mNode[object] as the first child than detaching all and reattaching back...
+
+    void setRenderFirst(int object)
+      {
+      if( object>=0 && object<NUM_OBJECTS)
+        {
+        for(int i=0; i<NUM_OBJECTS; i++)
+          {
+          mScreen.detach(mNode[i]);
+          }
+
+        mScreen.attach(mNode[object]);
+
+        for(int i=0; i<NUM_OBJECTS; i++)
+          {
+          if( i!=object )
+            mScreen.attach(mNode[i]);
+          }
+        }
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    public void onDrawFrame(GL10 glUnused) 
+      {
+      mScreen.render(System.currentTimeMillis());
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+    
+    public void onSurfaceCreated(GL10 glUnused, EGLConfig config) 
+      {
+      for(int i=0; i<NUM_OBJECTS; i++)
+        {
+        mTex[i].setColor(OBJECTS[NUM * i + 3]);
+        }
+
+      PostprocessEffectBlur.enable();
+      FragmentEffectAlpha.enable();
+
+      try
+        {
+        Distorted.onCreate(mView.getContext());
+        }
+      catch(Exception ex)
+        {
+        android.util.Log.e("Transparency", ex.getMessage() );
+        }
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    public void onSurfaceChanged(GL10 glUnused, int width, int height)
+      {
+      mScreenMin = width<height ? width:height;
+
+      float factor = 0.70f*mScreenMin/OBJ_SIZE;
+      mScale.set(factor,factor,factor);
+      mCenter.set((float)OBJ_SIZE/2, (float)OBJ_SIZE/2, -(float)OBJ_SIZE/2 );
+      mMove.set( (width -factor*OBJ_SIZE)/2 ,(height-factor*OBJ_SIZE)/2 ,0);
+
+      float size= 0.02f*OBJ_SIZE;
+
+      for(int i=0; i<NUM_OBJECTS; i++)
+        {
+        mMoveVector[i].set(size*OBJECTS[NUM*i], size*OBJECTS[NUM*i+1], size*OBJECTS[NUM*i+2]);
+        }
+
+      mScreen.resize(width, height);
+      }
+}
diff --git a/src/main/java/org/distorted/examples/transparency/TransparencySurfaceView.java b/src/main/java/org/distorted/examples/transparency/TransparencySurfaceView.java
new file mode 100644
index 0000000..82ce6c3
--- /dev/null
+++ b/src/main/java/org/distorted/examples/transparency/TransparencySurfaceView.java
@@ -0,0 +1,139 @@
+///////////////////////////////////////////////////////////////////////////////////////////////////
+// Copyright 2016 Leszek Koltunski                                                               //
+//                                                                                               //
+// This file is part of Distorted.                                                               //
+//                                                                                               //
+// Distorted is free software: you can redistribute it and/or modify                             //
+// it under the terms of the GNU General Public License as published by                          //
+// the Free Software Foundation, either version 2 of the License, or                             //
+// (at your option) any later version.                                                           //
+//                                                                                               //
+// Distorted is distributed in the hope that it will be useful,                                  //
+// but WITHOUT ANY WARRANTY; without even the implied warranty of                                //
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                                 //
+// GNU General Public License for more details.                                                  //
+//                                                                                               //
+// You should have received a copy of the GNU General Public License                             //
+// along with Distorted.  If not, see <http://www.gnu.org/licenses/>.                            //
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+package org.distorted.examples.transparency;
+
+import android.app.ActivityManager;
+import android.content.Context;
+import android.content.pm.ConfigurationInfo;
+import android.opengl.GLSurfaceView;
+import android.util.AttributeSet;
+import android.view.MotionEvent;
+import android.widget.Toast;
+
+import org.distorted.examples.R;
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+class TransparencySurfaceView extends GLSurfaceView
+{
+    private int mX, mY;
+    private TransparencyRenderer mRenderer;
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    public TransparencySurfaceView(Context context, AttributeSet attrs)
+      {
+      super(context, attrs);
+
+      mX = -1;
+      mY = -1;
+
+      if(!isInEditMode())
+        {
+        mRenderer = new TransparencyRenderer(this);
+        final ActivityManager activityManager     = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
+        final ConfigurationInfo configurationInfo = activityManager.getDeviceConfigurationInfo();
+        setEGLContextClientVersion( (configurationInfo.reqGlEsVersion>>16) >= 3 ? 3:2 );
+        setRenderer(mRenderer);
+        Toast.makeText(context, R.string.example_rotate_toast , Toast.LENGTH_SHORT).show();
+        }
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+
+    public TransparencyRenderer getRenderer()
+      {
+      return mRenderer;
+      }
+
+///////////////////////////////////////////////////////////////////////////////////////////////////
+    
+    @Override public boolean onTouchEvent(MotionEvent event) 
+      {
+      int action = event.getAction();
+      int x = (int)event.getX();
+      int y = (int)event.getY();
+           
+      switch(action)
+         {
+         case MotionEvent.ACTION_DOWN: mX = x;
+                                       mY = y;
+                                       break;
+                                       
+         case MotionEvent.ACTION_MOVE: if( mX>=0 && mY>= 0 )
+                                         {
+                                         float px = mY-y;
+                                         float py = mX-x;
+                                         float pz = 0;
+                                         float plen = (float)Math.sqrt(px*px + py*py + pz*pz);
+                                         
+                                         if( plen>0 )
+                                           {
+                                           px /= plen;
+                                           py /= plen;
+                                           pz /= plen;
+
+                                           float cosA = (float)Math.cos(plen*3.14f/mRenderer.mScreenMin);
+                                           float sinA = (float)Math.sqrt(1-cosA*cosA);
+                                         
+                                           mRenderer.mQuat1.set(px*sinA, py*sinA, pz*sinA, cosA);
+                                           }
+                                         }                             
+                                       break;
+                                       
+         case MotionEvent.ACTION_UP  : mX = -1;
+                                       mY = -1;
+        	                           
+                                       float qx = mRenderer.mQuat1.get1();
+                                       float qy = mRenderer.mQuat1.get2();
+                                       float qz = mRenderer.mQuat1.get3();
+                                       float qw = mRenderer.mQuat1.get4();
+
+                                       float rx = mRenderer.mQuat2.get1();
+                                       float ry = mRenderer.mQuat2.get2();
+                                       float rz = mRenderer.mQuat2.get3();
+                                       float rw = mRenderer.mQuat2.get4();
+
+                                       // This is quaternion multiplication. (tx,ty,tz,tw)
+                                       // is now equal to (qx,qy,qz,qw)*(rx,ry,rz,rw)
+                                       float tx = rw*qx - rz*qy + ry*qz + rx*qw;
+                                       float ty = rw*qy + rz*qx + ry*qw - rx*qz;
+                                       float tz = rw*qz + rz*qw - ry*qx + rx*qy;
+                                       float tw = rw*qw - rz*qz - ry*qy - rx*qx;
+
+                                       // The point of this is so that there are always
+                                       // exactly 2 quaternions: Quat1 representing the rotation
+                                       // accumulating only since the last screen touch, and Quat2
+                                       // which remembers the combined effect of all previous
+                                       // swipes.
+                                       // We cannot be accumulating an ever-growing list of quaternions
+                                       // and add a new one every time user swipes the screen - there
+                                       // is a limited number of slots in the EffectQueueMatrix!
+                                       mRenderer.mQuat1.set(0f, 0f, 0f, 1f);
+                                       mRenderer.mQuat2.set(tx, ty, tz, tw);
+                                       
+                                       break;
+         }
+             
+      return true;
+      }
+         
+}
+
diff --git a/src/main/res/layout/transparencylayout.xml b/src/main/res/layout/transparencylayout.xml
new file mode 100644
index 0000000..ae0a0b0
--- /dev/null
+++ b/src/main/res/layout/transparencylayout.xml
@@ -0,0 +1,77 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="fill_parent"
+    android:layout_height="fill_parent"
+    android:orientation="vertical" >
+
+    <org.distorted.examples.transparency.TransparencySurfaceView
+        android:id="@+id/transparencySurfaceView"
+        android:layout_width="fill_parent"
+        android:layout_height="0dp"
+        android:layout_weight="1" />
+
+    <LinearLayout
+        android:id="@+id/linearLayout1"
+        android:layout_width="fill_parent"
+        android:layout_height="100dp"
+        android:orientation="horizontal">
+
+        <LinearLayout
+            android:id="@+id/linearLayout2"
+            android:layout_width="wrap_content"
+            android:layout_height="fill_parent"
+            android:orientation="vertical"
+            android:layout_weight="0.1">
+
+            <RadioGroup
+                android:id="@+id/transparencyRadioGroup"
+                android:layout_width="fill_parent"
+                android:layout_height="fill_parent"
+                android:orientation="vertical">
+
+                <RadioButton
+                    android:id="@+id/transparencyRed"
+                    android:layout_width="fill_parent"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:background="@color/red"
+                    android:onClick="renderFirst"
+                    android:checked="true"
+                    android:textSize="14sp"/>
+
+                <RadioButton
+                    android:id="@+id/transparencyYellow"
+                    android:layout_width="fill_parent"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:background="@color/yellow"
+                    android:onClick="renderFirst"
+                    android:textSize="14sp"/>
+            </RadioGroup>
+        </LinearLayout>
+
+        <LinearLayout
+            android:id="@+id/linearLayout3"
+            android:layout_width="wrap_content"
+            android:layout_height="fill_parent"
+            android:orientation="vertical"
+            android:layout_weight="0.9">
+
+            <SeekBar
+                android:id="@+id/transparencySeekRed"
+                android:background="@color/red"
+                android:layout_height="50dp"
+                android:layout_width="fill_parent"
+                android:paddingLeft="10dp"
+                android:paddingRight="10dp" />
+            <SeekBar
+                android:id="@+id/transparencySeekYellow"
+                android:background="@color/yellow"
+                android:layout_height="50dp"
+                android:layout_width="fill_parent"
+                android:paddingLeft="10dp"
+                android:paddingRight="10dp" />
+
+        </LinearLayout>
+    </LinearLayout>
+</LinearLayout>
\ No newline at end of file
diff --git a/src/main/res/values/strings.xml b/src/main/res/values/strings.xml
index b48db72..ec44b14 100644
--- a/src/main/res/values/strings.xml
+++ b/src/main/res/values/strings.xml
@@ -159,6 +159,8 @@
     <string name="example_triblur_subtitle">Three different, blurred, obstructing objects.</string>
     <string name="example_postprocesstree">Postprocess Tree</string>
     <string name="example_postprocesstree_subtitle">Three layers of postprocessed surfaces.</string>
+    <string name="example_transparency">Transparency</string>
+    <string name="example_transparency_subtitle">Order Independent Transparency.</string>
     <string name="example_stencil">Stencil Buffer</string>
     <string name="example_stencil_subtitle">Implement the classic stencil example from https://open.gl/depthstencils</string>
     <string name="example_glow">Glowing Leaf</string>