Distorted Android

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

// Copyright 2018 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.library.main;

import android.opengl.GLES30;

import java.nio.Buffer;

import java.nio.ByteBuffer;

import java.nio.ByteOrder;

import java.nio.FloatBuffer;

import java.nio.IntBuffer;

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

/**

 * Implements OpenGL buffer object such as GL_ARRAY_BUFFER or GL_TRANSFORM_FEEDBACK_BUFFER.

 * Main point: deal with Android lifecycle and recreate the buffer on loss of OpenGL context.

 * <p>

 * Not part of public API, do not document (public only because has to be used in Meshes)

 *

 * @y.exclude

 */

public class InternalBuffer extends InternalObject

  {

  private static final int DONE     = 0;

  private static final int RECREATE = 1;

  private static final int UPDATE   = 2;

  private int mStatus, mSize;

  private final int[] mIndex;

  private final int mTarget, mUsage;

  private Buffer mBuffer;

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

  public InternalBuffer(int target, int usage)

    {

    super(InternalObject.TYPE_USER, InternalObject.STORAGE_PRIVATE );

    mIndex  = new int[1];

    mTarget = target;

    mUsage  = usage;

    mBuffer = null;

    mSize   = 0;

    mStatus = RECREATE;

    }

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

// must be called from a thread holding OpenGL Context.

  public int createImmediatelyFloat(int size, float[] buffer)

    {

    if( (mStatus & RECREATE) != 0 )

      {

      mSize= size;

      if( buffer!=null )

        {

        FloatBuffer buf = ByteBuffer.allocateDirect(size).order(ByteOrder.nativeOrder()).asFloatBuffer();

        buf.put(buffer).position(0);

        mBuffer = buf;

        }

      else

        {

        mBuffer = null;

        }

      GLES30.glGenBuffers( 1, mIndex, 0);

      GLES30.glBindBuffer( mTarget, mIndex[0]);

      GLES30.glBufferData( mTarget, mSize, mBuffer, mUsage);

      GLES30.glBindBuffer( mTarget, 0);

      markWasCreatedImmediately();

      }

    else if( (mStatus & UPDATE) != 0 )

      {

      updateFloat(buffer);

      }

    mStatus = DONE;

    return mIndex[0];

    }

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

// must be called from a thread holding OpenGL Context.

  public int createImmediatelyInt(int size, int[] buffer)

    {

    if( (mStatus & RECREATE) != 0 )

      {

      mSize= size;

      if( buffer!=null )

        {

        IntBuffer buf = ByteBuffer.allocateDirect(size).order(ByteOrder.nativeOrder()).asIntBuffer();

        buf.put(buffer).position(0);

        mBuffer = buf;

        }

      else

        {

        mBuffer = null;

        }

      GLES30.glGenBuffers( 1, mIndex, 0);

      GLES30.glBindBuffer( mTarget,  mIndex[0]);

      GLES30.glBufferData( mTarget, mSize, mBuffer, mUsage);

      GLES30.glBindBuffer( mTarget,  0);

      markWasCreatedImmediately();

      }

    else if( (mStatus & UPDATE) != 0  )

      {

      updateInt(buffer);

      }

    mStatus = DONE;

    return mIndex[0];

    }

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

// buffer non-null!!

  public void updateFloat(float[] buffer)

    {

    ((FloatBuffer)mBuffer).put(buffer).position(0);

    GLES30.glBindBuffer( mTarget, mIndex[0]);

    GLES30.glBufferData( mTarget, mSize, mBuffer, mUsage);

    GLES30.glBindBuffer( mTarget, 0);

    mStatus &= (~UPDATE);

    }

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

// buffer non-null!!

  public void updateInt(int[] buffer)

    {

    ((IntBuffer)mBuffer).put(buffer).position(0);

    GLES30.glBindBuffer( mTarget, mIndex[0]);

    GLES30.glBufferData( mTarget, mSize, mBuffer, mUsage);

    GLES30.glBindBuffer( mTarget, 0);

    mStatus &= (~UPDATE);

    }

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

  public void invalidate()

    {

    mStatus |= UPDATE;

    }

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

// Intentionally empty, no need to do anything here since it will be done in createImmediatelyXXX().

// In fact, recreating a Mesh's mVBO1 here - rather than in createImmediatelyFloat - was the reason

// of the 'disappearing cube after the mesh has changed from nice to simple' bug. I don't quite

// understand why TBH.

  void create()

    {

    }

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

// must be called from a thread holding OpenGL Context

  void delete()

    {

    GLES30.glDeleteBuffers(1, mIndex, 0);

    mStatus |= RECREATE;

    removeFromDone();

    }

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

  public void recreate()

    {

    mStatus |= RECREATE;

    }

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

// debugging only

  String printDetails()

    {

    return getClass().getSimpleName();

    }

  }