Distorted Android

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// 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/>.                            //

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package org.distorted.library.main;

import android.opengl.GLES30;

import java.nio.ByteBuffer;

import java.nio.ByteOrder;

import java.nio.FloatBuffer;

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/**

 * 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 final int[] mIndex;

  private int mTarget, mSize, mUsage;

  private FloatBuffer mBuffer;

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  public InternalBuffer(int target, int usage)

    {

    super(InternalObject.TYPE_USER);

    mIndex  = new int[1];

    mTarget = target;

    mUsage  = usage;

    mBuffer = null;

    mSize   = 0;

    recreate();

    }

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

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

    {

    if( mIndex[0]<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();

      }

    return mIndex[0];

    }

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// buffer non-null!!

  public void update(float[] buffer)

    {

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

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

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

    GLES30.glBindBuffer( mTarget, 0);

    }

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  public void invalidate()

    {

    recreate();

    }

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// must be called from a thread holding OpenGL Context

  void create()

    {

    if( mIndex[0]<0 )

      {

      GLES30.glGenBuffers( 1, mIndex, 0);

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

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

      GLES30.glBindBuffer( mTarget, 0);

      }

    }

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// must be called from a thread holding OpenGL Context

  void delete()

    {

    if( mIndex[0]>=0 )

      {

      GLES30.glDeleteBuffers(1, mIndex, 0);

      mIndex[0] = -1;

      }

    }

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  void recreate()

    {

    mIndex[0] = -1;

    }

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// debugging only

  String printDetails()

    {

    return getClass().getSimpleName();

    }

  }