// Tracks glBegin/glEnd calls to determine whether it is legal to
// query Vertex Buffer Object state
private boolean inBeginEndPair;

/* FIXME: refactor dependence on Java 2D / JOGL bridge

// Tracks creation and destruction of server-side OpenGL objects when
// the Java2D/OpenGL pipeline is enabled and it is using frame buffer
// objects (FBOs) to do its rendering
private GLObjectTracker tracker;

public void setObjectTracker(GLObjectTracker tracker) {
  this.tracker = tracker;
}

*/

public GL2ES12Impl(GLProfile glp, GLContextImpl context) {
  this._context = context; 
  this.bufferSizeTracker  = context.getBufferSizeTracker();
  this.bufferStateTracker = context.getBufferStateTracker();
  this.glStateTracker     = context.getGLStateTracker();
  this.isGL2ES2 = glp.isGL2ES2();
  this.glProfile = glp;
}

private boolean isGL2ES2;

public boolean isFunctionAvailable(String glFunctionName) {
  return _context.isFunctionAvailable(glFunctionName);
}

public boolean isExtensionAvailable(String glExtensionName) {
  return _context.isExtensionAvailable(glExtensionName);
}

public Object getExtension(String extensionName) {
  // At this point we don't expose any extensions using this mechanism
  return null;
}

/** Returns the context this GL object is associated with for better
    error checking by DebugGL. */
public GLContext getContext() {
  return _context;
}

private GLContextImpl _context;

public void setSwapInterval(int interval) {
  _context.setSwapInterval(interval);
}

public int getSwapInterval() {
  return _context.getSwapInterval();
}

public Object getPlatformGLExtensions() {
  return _context.getPlatformGLExtensions();
}

//
// Helpers for ensuring the correct amount of texture data
//

/** Returns the number of bytes required to fill in the appropriate
    texture. This is computed as closely as possible based on the
    pixel pack or unpack parameters. The logic in this routine is
    based on code in the SGI OpenGL sample implementation. */

private int imageSizeInBytes(int format, int type, int w, int h, int d,
                             boolean pack) {
  int elements = 0;
  int esize = 0;
  
  if (w < 0) return 0;
  if (h < 0) return 0;
  if (d < 0) return 0;
  switch (format) {
  case GL_STENCIL_INDEX:
    elements = 1;
    break;
  case GL_ALPHA:
  case GL_LUMINANCE:
  case GL_DEPTH_COMPONENT:
    elements = 1;
    break;
  case GL_LUMINANCE_ALPHA:
    elements = 2;
    break;
  case GL_RGB:
    elements = 3;
    break;
  case GL_RGBA:
    elements = 4;
    break;
  /* FIXME ?? 
   case GL_HILO_NV:
    elements = 2;
    break; */
  default:
    return 0;
  }
  switch (type) {
  case GL_BYTE:
  case GL_UNSIGNED_BYTE:
    esize = 1;
    break;
  case GL_SHORT:
  case GL_UNSIGNED_SHORT:
    esize = 2;
    break;
  case GL_UNSIGNED_SHORT_5_6_5:
  case GL_UNSIGNED_SHORT_4_4_4_4:
  case GL_UNSIGNED_SHORT_5_5_5_1:
    esize = 2;
    elements = 1;
    break;
  case GL_INT:
  case GL_UNSIGNED_INT:
  case GL_FLOAT:
    esize = 4;
    break;
  default:
    return 0;
  }
  return imageSizeInBytes(elements * esize, w, h, d, pack);
}

private GLBufferSizeTracker  bufferSizeTracker;
private GLBufferStateTracker bufferStateTracker;
private GLStateTracker       glStateTracker;

private boolean bufferObjectExtensionsInitialized = false;
private boolean haveGL15;
private boolean haveGL21;
private boolean haveARBVertexBufferObject;

private void initBufferObjectExtensionChecks() {
  if (bufferObjectExtensionsInitialized)
    return;
  bufferObjectExtensionsInitialized = true;
  haveGL15                  = isExtensionAvailable("GL_VERSION_1_5");
  haveGL21                  = isExtensionAvailable("GL_VERSION_2_1");
  haveARBVertexBufferObject = isExtensionAvailable("GL_ARB_vertex_buffer_object");
}

private boolean checkBufferObject(boolean extension1,
                                  boolean extension2,
                                  boolean extension3,
                                  boolean enabled,
                                  int state,
                                  String kind, boolean throwException) {
  if (inBeginEndPair) {
    throw new GLException("May not call this between glBegin and glEnd");
  }
  boolean avail = (extension1 || extension2 || extension3);
  if (!avail) {
    if (!enabled)
      return true;
    if(throwException) {
        throw new GLException("Required extensions not available to call this function");
    }
    return false;
  }
  int buffer = bufferStateTracker.getBoundBufferObject(state, this);
  if (enabled) {
    if (buffer == 0) {
      if(throwException) {
          throw new GLException(kind + " must be enabled to call this method");
      }
      return false;
    }
  } else {
    if (buffer != 0) {
      if(throwException) {
          throw new GLException(kind + " must be disabled to call this method");
      }
      return false;
    }
  }
  return true;
}  

private boolean checkArrayVBODisabled(boolean throwException) { 
  initBufferObjectExtensionChecks();
  return checkBufferObject(haveGL15,
                    haveARBVertexBufferObject,
                    false,
                    false,
                    GL.GL_ARRAY_BUFFER,
                    "array vertex_buffer_object", throwException);
}

private boolean checkArrayVBOEnabled(boolean throwException) { 
  initBufferObjectExtensionChecks();
  return checkBufferObject(haveGL15,
                    haveARBVertexBufferObject,
                    false,
                    true,
                    GL.GL_ARRAY_BUFFER,
                    "array vertex_buffer_object", throwException);
}

private boolean checkElementVBODisabled(boolean throwException) { 
  initBufferObjectExtensionChecks();
  return checkBufferObject(haveGL15,
                    haveARBVertexBufferObject,
                    false,
                    false,
                    GL.GL_ELEMENT_ARRAY_BUFFER,
                    "element vertex_buffer_object", throwException);
}

private boolean checkElementVBOEnabled(boolean throwException) { 
  initBufferObjectExtensionChecks();
  return checkBufferObject(haveGL15,
                    haveARBVertexBufferObject,
                    false,
                    true,
                    GL.GL_ELEMENT_ARRAY_BUFFER,
                    "element vertex_buffer_object", throwException);
}

private boolean checkUnpackPBODisabled(boolean throwException) { 
  // PBO n/a for ES 1.1 or ES 2.0
  return true;
}

private boolean checkUnpackPBOEnabled(boolean throwException) { 
  // PBO n/a for ES 1.1 or ES 2.0
  return false;
}

private boolean checkPackPBODisabled(boolean throwException) { 
  // PBO n/a for ES 1.1 or ES 2.0
  return true;
}

private boolean checkPackPBOEnabled(boolean throwException) { 
  // PBO n/a for ES 1.1 or ES 2.0
  return false;
}

// Attempt to return the same ByteBuffer object from glMapBuffer if
// the vertex buffer object's base address and size haven't changed
private static class ARBVBOKey {
  private long addr;
  private int  capacity;

  ARBVBOKey(long addr, int capacity) {
    this.addr = addr;
    this.capacity = capacity;
  }

  public int hashCode() {
    return (int) addr;
  }

  public boolean equals(Object o) {
    if ((o == null) || (!(o instanceof ARBVBOKey))) {
      return false;
    }

    ARBVBOKey other = (ARBVBOKey) o;
    return ((addr == other.addr) && (capacity == other.capacity));
  }
}

private Map/*<ARBVBOKey, ByteBuffer>*/ arbVBOCache = new HashMap();

/** Entry point to C language function: <br> <code> LPVOID glMapBuffer(GLenum target, GLenum access); </code>    */
public java.nio.ByteBuffer glMapBuffer(int target, int access) {
  final long __addr_ = ((GL2ES12ProcAddressTable)_context.getGLProcAddressTable())._addressof_glMapBuffer;
  if (__addr_ == 0) {
    throw new GLException("Method \"glMapBuffer\" not available");
  }
  int sz = bufferSizeTracker.getBufferSize(bufferStateTracker,
                                           target,
                                           this);
  long addr;
  addr = dispatch_glMapBuffer(target, access, __addr_);
  if (addr == 0 || sz == 0) {
    return null;
  }
  ARBVBOKey key = new ARBVBOKey(addr, sz);
  ByteBuffer _res = (ByteBuffer) arbVBOCache.get(key);
  if (_res == null) {
    _res = newDirectByteBuffer(addr, sz);
    InternalBufferUtil.nativeOrder(_res);
    arbVBOCache.put(key, _res);
  }
  _res.position(0);
  return _res;
}

/** Encapsulates function pointer for OpenGL function <br>: <code> LPVOID glMapBuffer(GLenum target, GLenum access); </code>    */
native private long dispatch_glMapBuffer(int target, int access, long glProcAddress);

native private ByteBuffer newDirectByteBuffer(long addr, int capacity);

  /** Dummy implementation for the ES 2.0 function: <br> <code> void {@native glShaderBinary}(GLint n, const GLuint *  shaders, GLenum binaryformat, const void *  binary, GLint length); </code>  <br> Always throws a GLException!  */
  public void glShaderBinary(int n, java.nio.IntBuffer shaders, int binaryformat, java.nio.Buffer binary, int length) {
    throw new GLException("Method \"glShaderBinary\" not available");
  }

  /** Dummy implementation for the ES 2.0 function: <br> <code> void {@native glShaderBinary}(GLint n, const GLuint *  shaders, GLenum binaryformat, const void *  binary, GLint length); </code>  <br> Always throws a GLException!  */
  public void glShaderBinary(int n, int[] shaders, int shaders_offset, int binaryformat, java.nio.Buffer binary, int length) {
    throw new GLException("Method \"glShaderBinary\" not available");
  }

  public void glReleaseShaderCompiler() {
    // nothing to do 
  }

    public void glVertexPointer(GLArrayData array) {
      if(array.getComponentNumber()==0) return;
      if(array.isVBO()) {
          glVertexPointer(array.getComponentNumber(), array.getComponentType(), array.getStride(), array.getOffset());
      } else {
          glVertexPointer(array.getComponentNumber(), array.getComponentType(), array.getStride(), array.getBuffer());
      }
    }
    public void glColorPointer(GLArrayData array) {
      if(array.getComponentNumber()==0) return;
      if(array.isVBO()) {
          glColorPointer(array.getComponentNumber(), array.getComponentType(), array.getStride(), array.getOffset());
      } else {
          glColorPointer(array.getComponentNumber(), array.getComponentType(), array.getStride(), array.getBuffer());
      }

    }
    public void glNormalPointer(GLArrayData array) {
      if(array.getComponentNumber()==0) return;
      if(array.getComponentNumber()!=3) {
        throw new GLException("Only 3 components per normal allowed");
      }
      if(array.isVBO()) {
          glNormalPointer(array.getComponentType(), array.getStride(), array.getOffset());
      } else {
          glNormalPointer(array.getComponentType(), array.getStride(), array.getBuffer());
      }
    }
    public void glTexCoordPointer(GLArrayData array) {
      if(array.getComponentNumber()==0) return;
      if(array.isVBO()) {
          glTexCoordPointer(array.getComponentNumber(), array.getComponentType(), array.getStride(), array.getOffset());
      } else {
          glTexCoordPointer(array.getComponentNumber(), array.getComponentType(), array.getStride(), array.getBuffer());
      }
    }