/**
 * Copyright 2010 JogAmp Community. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 *    1. Redistributions of source code must retain the above copyright notice, this list of
 *       conditions and the following disclaimer.
 *
 *    2. Redistributions in binary form must reproduce the above copyright notice, this list
 *       of conditions and the following disclaimer in the documentation and/or other materials
 *       provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY JogAmp Community ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL JogAmp Community OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * The views and conclusions contained in the software and documentation are those of the
 * authors and should not be interpreted as representing official policies, either expressed
 * or implied, of JogAmp Community.
 */

package com.jogamp.opengl.util;

import java.nio.Buffer;
import java.nio.ByteBuffer;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;
import java.nio.ShortBuffer;

import javax.media.opengl.GL;
import javax.media.opengl.GL2ES2;
import javax.media.opengl.GLArrayData;
import javax.media.opengl.GLBufferStorage;
import javax.media.opengl.GLException;
import javax.media.opengl.fixedfunc.GLPointerFuncUtil;

import com.jogamp.common.nio.Buffers;

import jogamp.opengl.util.GLArrayHandler;
import jogamp.opengl.util.GLArrayHandlerInterleaved;
import jogamp.opengl.util.GLDataArrayHandler;
import jogamp.opengl.util.GLFixedArrayHandler;
import jogamp.opengl.util.GLFixedArrayHandlerFlat;
import jogamp.opengl.util.glsl.GLSLArrayHandler;
import jogamp.opengl.util.glsl.GLSLArrayHandlerFlat;
import jogamp.opengl.util.glsl.GLSLArrayHandlerInterleaved;


public class GLArrayDataServer extends GLArrayDataClient implements GLArrayDataEditable {

  //
  // lifetime matters
  //

  /**
   * Create a VBO, using a predefined fixed function array index
   * and starting with a given Buffer object incl it's stride
   *
   * On profiles GL2 and ES1 the fixed function pipeline behavior is as expected.
   * On profile ES2 the fixed function emulation will transform these calls to
   * EnableVertexAttribArray and VertexAttribPointer calls,
   * and a predefined vertex attribute variable name will be chosen.
   *
   * The default name mapping will be used,
   * see {@link GLPointerFuncUtil#getPredefinedArrayIndexName(int)}.
   *
   * @param index The GL array index
   * @param compsPerElement component count per element
   * @param dataType The component's OpenGL data type
   * @param normalized Whether the data shall be normalized
   * @param stride in bytes from one element to the other. If zero, compsPerElement * compSizeInBytes
   * @param buffer the user define data
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   *
   * @see javax.media.opengl.GLContext#getPredefinedArrayIndexName(int)
   */
  public static GLArrayDataServer createFixed(int index, int compsPerElement, int dataType, boolean normalized, int stride,
                                              Buffer buffer, int vboUsage)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLFixedArrayHandler(ads);
    ads.init(null, index, compsPerElement, dataType, normalized, stride, buffer, buffer.limit(), 0 /* mappedElementCount */, false,
             glArrayHandler, 0, 0, vboUsage, GL.GL_ARRAY_BUFFER, false);
    return ads;
  }

  /**
   * Create a VBO, using a predefined fixed function array index
   * and starting with a new created Buffer object with initialElementCount size
   *
   * On profiles GL2 and ES1 the fixed function pipeline behavior is as expected.
   * On profile ES2 the fixed function emulation will transform these calls to
   * EnableVertexAttribArray and VertexAttribPointer calls,
   * and a predefined vertex attribute variable name will be chosen.
   *
   * The default name mapping will be used,
   * see {@link GLPointerFuncUtil#getPredefinedArrayIndexName(int)}.
   *
   * @param index The GL array index
   * @param compsPerElement component count per element
   * @param dataType The component's OpenGL data type
   * @param normalized Whether the data shall be normalized
   * @param initialElementCount
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   *
   * @see javax.media.opengl.GLContext#getPredefinedArrayIndexName(int)
   */
  public static GLArrayDataServer createFixed(int index, int compsPerElement, int dataType, boolean normalized, int initialElementCount,
                                              int vboUsage)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLFixedArrayHandler(ads);
    ads.init(null, index, compsPerElement, dataType, normalized, 0, null, initialElementCount, 0 /* mappedElementCount */, false,
             glArrayHandler, 0, 0, vboUsage, GL.GL_ARRAY_BUFFER, false);
    return ads;
  }

  /**
   * Create a VBO, using a custom GLSL array attribute name
   * and starting with a new created Buffer object with initialElementCount size
   * @param name  The custom name for the GL attribute
   * @param compsPerElement component count per element
   * @param dataType The component's OpenGL data type
   * @param normalized Whether the data shall be normalized
   * @param initialElementCount
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   */
  public static GLArrayDataServer createGLSL(String name, int compsPerElement,
                                             int dataType, boolean normalized, int initialElementCount, int vboUsage)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLSLArrayHandler(ads);
    ads.init(name, -1, compsPerElement, dataType, normalized, 0, null, initialElementCount,
             0 /* mappedElementCount */, true, glArrayHandler, 0, 0, vboUsage, GL.GL_ARRAY_BUFFER, true);
    return ads;
  }

  /**
   * Create a VBO, using a custom GLSL array attribute name
   * intended for GPU buffer storage mapping, see {@link GLBufferStorage}, via {@link #mapStorage(GL, int)} and {@link #mapStorage(GL, long, long, int)}.
   * @param name  The custom name for the GL attribute
   * @param compsPerElement component count per element
   * @param dataType The component's OpenGL data type
   * @param normalized Whether the data shall be normalized
   * @param mappedElementCount
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   */
  public static GLArrayDataServer createGLSLMapped(String name, int compsPerElement,
                                                   int dataType, boolean normalized, int mappedElementCount, int vboUsage)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLSLArrayHandler(ads);
    ads.init(name, -1, compsPerElement, dataType, normalized, 0, null, 0 /* initialElementCount */,
             mappedElementCount, true, glArrayHandler, 0, 0, vboUsage, GL.GL_ARRAY_BUFFER, true);
    ads.seal(true);
    return ads;
  }

  /**
   * Create a VBO, using a custom GLSL array attribute name
   * and starting with a given Buffer object incl it's stride
   * @param name  The custom name for the GL attribute
   * @param compsPerElement component count per element
   * @param dataType The component's OpenGL data type
   * @param normalized Whether the data shall be normalized
   * @param stride in bytes from one element to the other. If zero, compsPerElement * compSizeInBytes
   * @param buffer the user define data
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   */
  public static GLArrayDataServer createGLSL(String name, int compsPerElement,
                                             int dataType, boolean normalized, int stride, Buffer buffer,
                                             int vboUsage)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLSLArrayHandler(ads);
    ads.init(name, -1, compsPerElement, dataType, normalized, stride, buffer, buffer.limit(), 0 /* mappedElementCount */, true,
             glArrayHandler, 0, 0, vboUsage, GL.GL_ARRAY_BUFFER, true);
    return ads;
  }

  /**
   * Create a VBO data object for any target w/o render pipeline association, ie {@link GL#GL_ELEMENT_ARRAY_BUFFER}.
   *
   * Hence no index, name for a fixed function pipeline nor vertex attribute is given.
   *
   * @param compsPerElement component count per element
   * @param dataType The component's OpenGL data type
   * @param stride in bytes from one element to the other. If zero, compsPerElement * compSizeInBytes
   * @param buffer the user define data
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   * @param vboTarget {@link GL#GL_ELEMENT_ARRAY_BUFFER}, ..
   * {@link GL#glGenBuffers(int, int[], int)
   */
  public static GLArrayDataServer createData(int compsPerElement, int dataType, int stride,
                                             Buffer buffer, int vboUsage, int vboTarget)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLDataArrayHandler(ads);
    ads.init(null, -1, compsPerElement, dataType, false, stride, buffer, buffer.limit(), 0 /* mappedElementCount */, false,
             glArrayHandler, 0, 0, vboUsage, vboTarget, false);
    return ads;
  }

  /**
   * Create a VBO data object for any target w/o render pipeline association, ie {@link GL#GL_ELEMENT_ARRAY_BUFFER}.
   *
   * Hence no index, name for a fixed function pipeline nor vertex attribute is given.
   *
   * @param compsPerElement component count per element
   * @param dataType The component's OpenGL data type
   * @param initialElementCount
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   * @param vboTarget {@link GL#GL_ELEMENT_ARRAY_BUFFER}, ..
   */
  public static GLArrayDataServer createData(int compsPerElement, int dataType, int initialElementCount,
                                             int vboUsage, int vboTarget)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLDataArrayHandler(ads);
    ads.init(null, -1, compsPerElement, dataType, false, 0, null, initialElementCount, 0 /* mappedElementCount */, false,
             glArrayHandler, 0, 0, vboUsage, vboTarget, false);
    return ads;
  }

  /**
   * Create a VBO data object for any target w/o render pipeline association, i.e. {@link GL#GL_ELEMENT_ARRAY_BUFFER},
   * intended for GPU buffer storage mapping, see {@link GLBufferStorage}, via {@link #mapStorage(GL, int)} and {@link #mapStorage(GL, long, long, int)}.
   * <p>
   * No index, name for a fixed function pipeline nor vertex attribute is given.
   * </p>
   *
   * @param compsPerElement component count per element
   * @param dataType The component's OpenGL data type
   * @param initialElementCount
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   * @param vboTarget {@link GL#GL_ELEMENT_ARRAY_BUFFER}, ..
   */
  public static GLArrayDataServer createDataMapped(int compsPerElement, int dataType, int mappedElementCount,
                                                   int vboUsage, int vboTarget)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLDataArrayHandler(ads);
    ads.init(null, -1, compsPerElement, dataType, false, 0, null, 0 /* initialElementCount */, mappedElementCount, false,
             glArrayHandler, 0, 0, vboUsage, vboTarget, false);
    return ads;
  }

  /**
   * Create a VBO for fixed function interleaved array data
   * starting with a new created Buffer object with initialElementCount size.
   * <p>User needs to <i>configure</i> the interleaved segments via {@link #addFixedSubArray(int, int, int)}.</p>
   *
   * @param compsPerElement The total number of all interleaved components per element.
   * @param dataType The component's OpenGL data type
   * @param normalized Whether the data shall be normalized
   * @param initialElementCount The initial number of all interleaved elements
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   */
  public static GLArrayDataServer createFixedInterleaved(int compsPerElement, int dataType, boolean normalized, int initialElementCount,
                                              int vboUsage)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLArrayHandlerInterleaved(ads);
    ads.init(GLPointerFuncUtil.mgl_InterleaveArray, -1, compsPerElement, dataType, false, 0, null, initialElementCount, 0 /* mappedElementCount */, false,
             glArrayHandler, 0, 0, vboUsage, GL.GL_ARRAY_BUFFER, false);
    return ads;
  }

  /**
   * Create a VBO for fixed function interleaved array data
   * intended for GPU buffer storage mapping, see {@link GLBufferStorage}, via {@link #mapStorage(GL, int)} and {@link #mapStorage(GL, long, long, int)}.
   * <p>User needs to <i>configure</i> the interleaved segments via {@link #addFixedSubArray(int, int, int)}.</p>
   *
   * @param compsPerElement The total number of all interleaved components per element.
   * @param dataType The component's OpenGL data type
   * @param normalized Whether the data shall be normalized
   * @param mappedElementCount The total number of all interleaved elements
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   */
  public static GLArrayDataServer createFixedInterleavedMapped(int compsPerElement, int dataType, boolean normalized, int mappedElementCount,
                                                               int vboUsage)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLArrayHandlerInterleaved(ads);
    ads.init(GLPointerFuncUtil.mgl_InterleaveArray, -1, compsPerElement, dataType, false, 0, null, 0 /* initialElementCount */, mappedElementCount, false,
             glArrayHandler, 0, 0, vboUsage, GL.GL_ARRAY_BUFFER, false);
    ads.seal(true);
    return ads;
  }

  /**
   * Create a VBO for fixed function interleaved array data
   * starting with a given Buffer object incl it's stride
   * <p>User needs to <i>configure</i> the interleaved segments via {@link #addFixedSubArray(int, int, int)}.</p>
   *
   * @param compsPerElement The total number of all interleaved components per element.
   * @param dataType The component's OpenGL data type
   * @param normalized Whether the data shall be normalized
   * @param stride in bytes from one element of a sub-array to the other. If zero, compsPerElement * compSizeInBytes
   * @param buffer The user define data of all interleaved elements
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   */
  public static GLArrayDataServer createFixedInterleaved(int compsPerElement, int dataType, boolean normalized, int stride, Buffer buffer,
                                              int vboUsage)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLArrayHandlerInterleaved(ads);
    ads.init(GLPointerFuncUtil.mgl_InterleaveArray, -1, compsPerElement, dataType, normalized, stride, buffer, buffer.limit(), 0 /* mappedElementCount */, false,
             glArrayHandler, 0, 0, vboUsage, GL.GL_ARRAY_BUFFER, false);
    return ads;
  }

  /**
   * Configure a segment of this fixed function interleaved array (see {@link #createFixedInterleaved(int, int, boolean, int, int)}).
   * <p>
   * This method may be called several times as long the sum of interleaved components does not
   * exceed the total component count of the created interleaved array.</p>
   * <p>
   * The memory of the the interleaved array is being used.</p>
   * <p>
   * Must be called before using the array, eg: {@link #seal(boolean)}, {@link #putf(float)}, .. </p>
   *
   * @param index The GL array index, maybe -1 if vboTarget is {@link GL#GL_ELEMENT_ARRAY_BUFFER}
   * @param comps This interleaved array segment's component count per element
   * @param vboTarget {@link GL#GL_ARRAY_BUFFER} or {@link GL#GL_ELEMENT_ARRAY_BUFFER}
   */
  public GLArrayData addFixedSubArray(int index, int comps, int vboTarget) {
      if(interleavedOffset >= getComponentCount() * getComponentSizeInBytes()) {
          final int iOffC = interleavedOffset / getComponentSizeInBytes();
          throw new GLException("Interleaved offset > total components ("+iOffC+" > "+getComponentCount()+")");
      }
      if(usesGLSL) {
          throw new GLException("buffer uses GLSL");
      }
      final int subStrideB = ( 0 == getStride() ) ? getComponentCount() * getComponentSizeInBytes() : getStride();
      final GLArrayDataWrapper ad;
      if( 0 < mappedElementCount ) {
          ad = GLArrayDataWrapper.createFixed(
                  index, comps, getComponentType(),
                  getNormalized(), subStrideB, mappedElementCount,
                  getVBOName(), interleavedOffset, getVBOUsage(), vboTarget);
      } else {
          ad = GLArrayDataWrapper.createFixed(
                  index, comps, getComponentType(),
                  getNormalized(), subStrideB, getBuffer(),
                  getVBOName(), interleavedOffset, getVBOUsage(), vboTarget);
      }
      ad.setVBOEnabled(isVBO());
      interleavedOffset += comps * getComponentSizeInBytes();
      if(GL.GL_ARRAY_BUFFER == vboTarget) {
          glArrayHandler.addSubHandler(new GLFixedArrayHandlerFlat(ad));
      }
      return ad;
  }

  /**
   * Create a VBO for GLSL interleaved array data
   * starting with a new created Buffer object with initialElementCount size.
   * <p>User needs to <i>configure</i> the interleaved segments via {@link #addGLSLSubArray(int, int, int)}.</p>
   *
   * @param compsPerElement The total number of all interleaved components per element.
   * @param dataType The component's OpenGL data type
   * @param normalized Whether the data shall be normalized
   * @param initialElementCount The initial number of all interleaved elements
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   */
  public static GLArrayDataServer createGLSLInterleaved(int compsPerElement, int dataType, boolean normalized, int initialElementCount,
                                                        int vboUsage)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLSLArrayHandlerInterleaved(ads);
    ads.init(GLPointerFuncUtil.mgl_InterleaveArray, -1, compsPerElement, dataType, normalized, 0, null, initialElementCount, 0 /* mappedElementCount */, false,
             glArrayHandler, 0, 0, vboUsage, GL.GL_ARRAY_BUFFER, true);
    return ads;
  }

  /**
   * Create a VBO for GLSL interleaved array data
   * intended for GPU buffer storage mapping, see {@link GLBufferStorage}, via {@link #mapStorage(GL, int)} and {@link #mapStorage(GL, long, long, int)}.
   * <p>User needs to <i>configure</i> the interleaved segments via {@link #addGLSLSubArray(int, int, int)}.</p>
   *
   * @param compsPerElement The total number of all interleaved components per element.
   * @param dataType The component's OpenGL data type
   * @param normalized Whether the data shall be normalized
   * @param mappedElementCount The total number of all interleaved elements
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   */
  public static GLArrayDataServer createGLSLInterleavedMapped(int compsPerElement, int dataType, boolean normalized, int mappedElementCount, int vboUsage)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLSLArrayHandlerInterleaved(ads);
    ads.init(GLPointerFuncUtil.mgl_InterleaveArray, -1, compsPerElement, dataType, normalized, 0, null, 0 /* initialElementCount */, mappedElementCount, false,
             glArrayHandler, 0, 0, vboUsage, GL.GL_ARRAY_BUFFER, true);
    ads.seal(true);
    return ads;
  }

  /**
   * Create a VBO for GLSL interleaved array data
   * starting with a given Buffer object incl it's stride
   * <p>User needs to <i>configure</i> the interleaved segments via {@link #addGLSLSubArray(int, int, int)}.</p>
   *
   * @param compsPerElement The total number of all interleaved components per element.
   * @param dataType The component's OpenGL data type
   * @param normalized Whether the data shall be normalized
   * @param stride in bytes from one element of a sub-array to the other. If zero, compsPerElement * compSizeInBytes
   * @param buffer The user define data of all interleaved elements
   * @param vboUsage {@link GL2ES2#GL_STREAM_DRAW}, {@link GL#GL_STATIC_DRAW} or {@link GL#GL_DYNAMIC_DRAW}
   */
  public static GLArrayDataServer createGLSLInterleaved(int compsPerElement, int dataType, boolean normalized, int stride, Buffer buffer,
                                                        int vboUsage)
    throws GLException
  {
    GLArrayDataServer ads = new GLArrayDataServer();
    GLArrayHandler glArrayHandler = new GLSLArrayHandlerInterleaved(ads);
    ads.init(GLPointerFuncUtil.mgl_InterleaveArray, -1, compsPerElement, dataType, normalized, stride, buffer, buffer.limit(), 0 /* mappedElementCount */, false,
             glArrayHandler, 0, 0, vboUsage, GL.GL_ARRAY_BUFFER, true);
    return ads;
  }

  /**
   * Configure a segment of this GLSL interleaved array (see {@link #createGLSLInterleaved(int, int, boolean, int, int)}).
   * <p>
   * This method may be called several times as long the sum of interleaved components does not
   * exceed the total component count of the created interleaved array.</p>
   * <p>
   * The memory of the the interleaved array is being used.</p>
   * <p>
   * Must be called before using the array, eg: {@link #seal(boolean)}, {@link #putf(float)}, .. </p>
   * @param name  The custom name for the GL attribute, maybe null if vboTarget is {@link GL#GL_ELEMENT_ARRAY_BUFFER}
   * @param comps This interleaved array segment's component count per element
   * @param vboTarget {@link GL#GL_ARRAY_BUFFER} or {@link GL#GL_ELEMENT_ARRAY_BUFFER}
   */
  public GLArrayData addGLSLSubArray(String name, int comps, int vboTarget) {
      if(interleavedOffset >= getComponentCount() * getComponentSizeInBytes()) {
          final int iOffC = interleavedOffset / getComponentSizeInBytes();
          throw new GLException("Interleaved offset > total components ("+iOffC+" > "+getComponentCount()+")");
      }
      if(!usesGLSL) {
          throw new GLException("buffer uses fixed function");
      }
      final int subStrideB = ( 0 == getStride() ) ? getComponentCount() * getComponentSizeInBytes() : getStride();
      final GLArrayDataWrapper ad;
      if( 0 < mappedElementCount ) {
          ad = GLArrayDataWrapper.createGLSL(
                  name, comps, getComponentType(),
                  getNormalized(), subStrideB, mappedElementCount,
                  getVBOName(), interleavedOffset, getVBOUsage(), vboTarget);
      } else {
          ad = GLArrayDataWrapper.createGLSL(
                  name, comps, getComponentType(),
                  getNormalized(), subStrideB, getBuffer(),
                  getVBOName(), interleavedOffset, getVBOUsage(), vboTarget);
      }
      ad.setVBOEnabled(isVBO());
      interleavedOffset += comps * getComponentSizeInBytes();
      if(GL.GL_ARRAY_BUFFER == vboTarget) {
          glArrayHandler.addSubHandler(new GLSLArrayHandlerFlat(ad));
      }
      return ad;
  }

  public final void setInterleavedOffset(int interleavedOffset) {
    this.interleavedOffset = interleavedOffset;
  }

  public final int getInterleavedOffset() {
    return interleavedOffset;
  }

  //
  // Data matters GLArrayData
  //

  //
  // Data and GL state modification ..
  //

  @Override
  public void destroy(GL gl) {
    // super.destroy(gl):
    // - GLArrayDataClient.destroy(gl): disables & clears client-side buffer
    //   - GLArrayDataWrapper.destroy(gl) (clears all values 'vboName' ..)
    int _vboName = vboName;
    super.destroy(gl);
    if(_vboName!=0) {
        final int[] tmp = new int[] { _vboName } ;
        gl.glDeleteBuffers(1, tmp, 0);
        vboName = 0;
    }
  }

  //
  // data matters
  //

  /**
   * Convenient way do disable the VBO behavior and
   * switch to client side data one
   * Only possible if buffer is defined.
   */
  @Override
  public void setVBOEnabled(boolean vboUsage) {
    checkSeal(false);
    super.setVBOEnabled(vboUsage);
  }

  public GLBufferStorage mapStorage(GL gl, int access) {
      if( null != this.getBuffer() ) {
          throw new IllegalStateException("user buffer not null");
      }
      if( null != mappedStorage ) {
          throw new IllegalStateException("already mapped: "+mappedStorage);
      }
      checkSeal(true);
      bindBuffer(gl, true);
      gl.glBufferData(getVBOTarget(), getSizeInBytes(), null, getVBOUsage());
      final GLBufferStorage storage = gl.mapBuffer(getVBOTarget(), access);
      setMappedBuffer(storage);
      bindBuffer(gl, false);
      seal(false);
      rewind();
      return storage;
  }
  public GLBufferStorage mapStorage(GL gl, long offset, long length, int access) {
      if( null != this.getBuffer() ) {
          throw new IllegalStateException("user buffer not null");
      }
      if( null != mappedStorage ) {
          throw new IllegalStateException("already mapped: "+mappedStorage);
      }
      checkSeal(true);
      bindBuffer(gl, true);
      gl.glBufferData(getVBOTarget(), getSizeInBytes(), null, getVBOUsage());
      final GLBufferStorage storage = gl.mapBufferRange(getVBOTarget(), offset, length, access);
      setMappedBuffer(storage);
      bindBuffer(gl, false);
      seal(false);
      rewind();
      return storage;
  }
  private final void setMappedBuffer(GLBufferStorage storage) {
      mappedStorage = storage;
      final ByteBuffer bb = storage.getMappedBuffer();
      if(componentClazz==ByteBuffer.class) {
          buffer = bb;
      } else if(componentClazz==ShortBuffer.class) {
          buffer = bb.asShortBuffer();
      } else if(componentClazz==IntBuffer.class) {
          buffer = bb.asIntBuffer();
      } else if(componentClazz==FloatBuffer.class) {
          buffer = bb.asFloatBuffer();
      } else {
          throw new GLException("Given Buffer Class not supported: "+componentClazz+":\n\t"+this);
      }
  }

  public void unmapStorage(GL gl) {
      if( null == mappedStorage ) {
          throw new IllegalStateException("not mapped");
      }
      mappedStorage = null;
      buffer = null;
      seal(true);
      bindBuffer(gl, true);
      gl.glUnmapBuffer(getVBOTarget());
      bindBuffer(gl, false);
  }

  @Override
  public String toString() {
    return "GLArrayDataServer["+name+
                       ", index "+index+
                       ", location "+location+
                       ", isVertexAttribute "+isVertexAttribute+
                       ", usesGLSL "+usesGLSL+
                       ", usesShaderState "+(null!=shaderState)+
                       ", dataType 0x"+Integer.toHexString(componentType)+
                       ", bufferClazz "+componentClazz+
                       ", elements "+getElementCount()+
                       ", components "+componentsPerElement+
                       ", stride "+strideB+"b "+strideL+"c"+
                       ", initialElementCount "+initialElementCount+
                       ", mappedElementCount "+mappedElementCount+
                       ", mappedStorage "+mappedStorage+
                       ", vboEnabled "+vboEnabled+
                       ", vboName "+vboName+
                       ", vboUsage 0x"+Integer.toHexString(vboUsage)+
                       ", vboTarget 0x"+Integer.toHexString(vboTarget)+
                       ", vboOffset "+vboOffset+
                       ", sealed "+sealed+
                       ", bufferEnabled "+bufferEnabled+
                       ", bufferWritten "+bufferWritten+
                       ", buffer "+buffer+
                       ", alive "+alive+
                       "]";
  }

  //
  // non public matters ..
  //

  @Override
  protected void init(String name, int index, int comps, int dataType, boolean normalized,
                      int stride, Buffer data, int initialElementCount, int mappedElementCount,
                      boolean isVertexAttribute,
                      GLArrayHandler glArrayHandler, int vboName, long vboOffset, int vboUsage, int vboTarget, boolean usesGLSL)
    throws GLException
  {
    super.init(name, index, comps, dataType, normalized, stride, data, initialElementCount, mappedElementCount, isVertexAttribute,
               glArrayHandler, vboName, vboOffset, vboUsage, vboTarget, usesGLSL);

    vboEnabled=true;
  }

  @Override
  protected void init_vbo(GL gl) {
    super.init_vbo(gl);
    if(vboEnabled && vboName==0) {
        int[] tmp = new int[1];
        gl.glGenBuffers(1, tmp, 0);
        vboName = tmp[0];
        if(0 < interleavedOffset) {
            glArrayHandler.setSubArrayVBOName(vboName);
        }
    }
  }

  protected GLArrayDataServer() { }

  /**
   * Copy Constructor
   * <p>
   * Buffer is {@link Buffers#slice(Buffer) sliced}, i.e. sharing content but using own state.
   * </p>
   * <p>
   * All other values are simply copied.
   * </p>
   */
  public GLArrayDataServer(GLArrayDataServer src) {
    super(src);
    this.interleavedOffset = src.interleavedOffset;
    this.mappedStorage = src.mappedStorage;
  }

  private int interleavedOffset = 0;
  private GLBufferStorage mappedStorage = null;
}

