Distorted Android

import java.util.HashMap;

import java.util.LinkedList;

/**

 * Keep all objects created in a static LinkedList. The point: we need to be able to mark

 * Objects for deletion, and delete all marked Objects later at a convenient time (that's

 * because we can only delete from a thread that holds the OpenGL context so here we provide a

 * framework where one is able to mark for deletion at any time and actual deletion takes place

 * on the next render).

*/

abstract class DistortedSurface

  {

  static final int FAILED_TO_CREATE = 1;

  static final int NOT_CREATED_YET  = 2;

  static final int DONT_CREATE      = 3;

  static final int CREATED          = 4;

  static final int TYPE_USER = 0;

  static final int TYPE_TREE = 1;

  static final int TYPE_SYST = 2;

  private static final int JOB_CREATE = 0;

  private static final int JOB_DELETE = 1;

  private class Job

    {

    DistortedSurface surface;

    int action;

    Job(DistortedSurface s, int a)

      {

      surface = s;

      action  = a;

      }

    }

  private static boolean mToDo = false;

  private static LinkedList<DistortedSurface> mDoneList = new LinkedList<>();

  private static HashMap<Long,Job> mToDoMap = new HashMap<>();

  private static long mNextClientID = 0;

  private static long mNextSystemID = 0;

  private long mID;

  private int mType;

///////////////////////////////////////////////////////////////////////////////////////////////////

  abstract void create();

  abstract void delete();

  abstract void recreate();

///////////////////////////////////////////////////////////////////////////////////////////////////

// must be called from a thread holding OpenGL Context

  static synchronized boolean toDo()

    {

    if( mToDo )

      {

      Job job;

      DistortedSurface surface;

      for(Long key: mToDoMap.keySet())

        {

        job = mToDoMap.get(key);

        surface = job.surface;

        //android.util.Log.d("SURFACE", "  ---> need to "+(job.action==JOB_CREATE ? "create":"delete")+" surfaceID="+surface.getID() );

        if( job.action==JOB_CREATE )

          {

          surface.create();

          mDoneList.add(surface);

          }

        else if( job.action==JOB_DELETE )

          {

          surface.delete();

          }

        }

      mToDoMap.clear();

      mToDo = false;

      return true;

      }

    return false;

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  static synchronized void onPause()

    {

    DistortedSurface surface;

    int num = mDoneList.size();

    for(int i=0; i<num; i++)

      {

      surface = mDoneList.removeFirst();

      mToDoMap.put(surface.getID(), surface.new Job(surface,JOB_CREATE) );

      surface.recreate();

      }

    mToDo = true;

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  static synchronized void onDestroy()

    {

    mToDoMap.clear();

    mDoneList.clear();

    mToDo = true;

    mNextClientID = 0;

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  @SuppressWarnings("unused")

  static void debugLists()

    {

    android.util.Log.e("Surface", "Done list:");

    DistortedSurface surface;

    int num = mDoneList.size();

    for(int i=0; i<num; i++)

      {

      surface = mDoneList.get(i);

      surface.print(i, "");

      }

    android.util.Log.e("Surface", "ToDo list:");

    Job job;

    int i=0;

    for(Long key: mToDoMap.keySet())

      {

      job = mToDoMap.get(key);

      job.surface.print(i++, job.action==JOB_CREATE ? " create":" delete");

      }

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  private void print(int i, String extra)

    {

    String str;

    if( this instanceof DistortedFramebuffer ) str = (i+": Framebuffer ");

    else if( this instanceof DistortedTexture) str = (i+": Texture     ");

    else if( this instanceof DistortedScreen ) str = (i+": Screen      ");

    else                                       str = (i+": UNKNOWN     ");

    str += ("("+getWidth()+","+getHeight()+") surfaceID:"+getID());

    switch(mType)

      {

      case TYPE_SYST: str+=" SYSTEM"; break;

      case TYPE_USER: str+=" USER"  ; break;

      case TYPE_TREE: str+=" TREE"  ; break;

      default       : str+=" ERROR??";

      }

    android.util.Log.e("Surface", str+extra);

    }

    mID           = type==TYPE_SYST ? --mNextSystemID : ++mNextClientID;

    mType         = type;

    if( create!=DONT_CREATE )

      {

      mToDoMap.put(mID, new Job(this,JOB_CREATE) );

      mToDo = true;

      }

  synchronized void markForCreation()

    mDoneList.remove(this);

    mToDoMap.put(mID, new Job(this,JOB_CREATE) );

    mToDo = true;

/**

 * Mark the underlying OpenGL object for deletion. Actual deletion will take place on the next render.

 */

  synchronized public void markForDeletion()

    {

    mDoneList.remove(this);

    mToDoMap.put(mID, new Job(this,JOB_DELETE) );

    mToDo = true;

    }

////////////////////////////////////////////////////////////////////////////////////////////////////

/**

 * Return unique ID of this Surface.

 */

  public long getID()

    {

    return mID;

    }

///////////////////////////////////////////////////////////////////////////////////////////////////

  }