gst-libs/gst/gl/gstglbuffer.c - mtk-gst-plugins-bad-debian - Git at Google

 /*
  * GStreamer
  * Copyright (C) 2015 Matthew Waters <matthew@centricular.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library 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
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public
  * License along with this library; if not, write to the
  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */

 #ifdef HAVE_CONFIG_H
 #include "config.h"
 #endif

 #include <string.h>

 #include "gstglbuffer.h"
 #include "gstglutils.h"

 /**
  * SECTION:gstglbuffer
  * @short_description: memory subclass for GL buffers
  * @see_also: #GstMemory, #GstAllocator
  *
  * GstGLBuffer is a #GstMemory subclass providing support for the mapping of
  * GL buffers.
  *
  * Data is uploaded or downloaded from the GPU as is necessary.
  */

 /* Implementation notes:
  *
  * Currently does not take into account GLES2 differences (no mapbuffer)
  */

 #define USING_OPENGL(context) (gst_gl_context_check_gl_version (context, GST_GL_API_OPENGL, 1, 0))
 #define USING_OPENGL3(context) (gst_gl_context_check_gl_version (context, GST_GL_API_OPENGL3, 3, 1))
 #define USING_GLES(context) (gst_gl_context_check_gl_version (context, GST_GL_API_GLES, 1, 0))
 #define USING_GLES2(context) (gst_gl_context_check_gl_version (context, GST_GL_API_GLES2, 2, 0))
 #define USING_GLES3(context) (gst_gl_context_check_gl_version (context, GST_GL_API_GLES2, 3, 0))

 /* compatibility definitions... */
 #ifndef GL_MAP_READ_BIT
 #define GL_MAP_READ_BIT 0x0001
 #endif
 #ifndef GL_MAP_WRITE_BIT
 #define GL_MAP_WRITE_BIT 0x0002
 #endif
 #ifndef GL_COPY_READ_BUFFER
 #define GL_COPY_READ_BUFFER 0x8F36
 #endif
 #ifndef GL_COPY_WRITE_BUFFER
 #define GL_COPY_WRITE_BUFFER 0x8F37
 #endif

 GST_DEBUG_CATEGORY_STATIC (GST_CAT_GL_BUFFER);
 #define GST_CAT_DEFUALT GST_CAT_GL_BUFFER

 static GstAllocator *_gl_buffer_allocator;

 static gboolean
 _gl_buffer_create (GstGLBuffer * gl_mem, GError ** error)
 {
   const GstGLFuncs *gl = gl_mem->mem.context->gl_vtable;

   gl->GenBuffers (1, &gl_mem->id);
   gl->BindBuffer (gl_mem->target, gl_mem->id);
   gl->BufferData (gl_mem->target, gl_mem->mem.mem.maxsize, NULL,
       gl_mem->usage_hints);
   gl->BindBuffer (gl_mem->target, 0);

   return TRUE;
 }

 struct create_data
 {
   GstGLBuffer *mem;
   gboolean result;
 };

 static void
 _gl_buffer_init (GstGLBuffer * mem, GstAllocator * allocator,
     GstMemory * parent, GstGLContext * context, guint gl_target, guint gl_usage,
     GstAllocationParams * params, gsize size)
 {
   mem->target = gl_target;
   mem->usage_hints = gl_usage;

   gst_gl_base_memory_init ((GstGLBaseMemory *) mem, allocator, parent, context,
       params, size, NULL, NULL);

   GST_CAT_DEBUG (GST_CAT_GL_BUFFER, "new GL buffer memory:%p size:%"
       G_GSIZE_FORMAT, mem, mem->mem.mem.maxsize);
 }

 static GstGLBuffer *
 _gl_buffer_new (GstAllocator * allocator, GstMemory * parent,
     GstGLContext * context, guint gl_target, guint gl_usage,
     GstAllocationParams * params, gsize size)
 {
   GstGLBuffer *ret = g_new0 (GstGLBuffer, 1);
   _gl_buffer_init (ret, allocator, parent, context, gl_target, gl_usage,
       params, size);

   return ret;
 }

 static gpointer
 gst_gl_buffer_cpu_access (GstGLBuffer * mem, GstMapInfo * info, gsize size)
 {
   const GstGLFuncs *gl = mem->mem.context->gl_vtable;
   gpointer data, ret;

   if (!gst_gl_base_memory_alloc_data (GST_GL_BASE_MEMORY_CAST (mem)))
     return NULL;

   ret = mem->mem.data;

   GST_CAT_LOG (GST_CAT_GL_BUFFER, "mapping id %d size %" G_GSIZE_FORMAT,
       mem->id, size);

   /* The extra data pointer indirection/memcpy is needed for coherent across
    * concurrent map()'s in both GL and CPU */
   if (GST_MEMORY_FLAG_IS_SET (mem, GST_GL_BASE_MEMORY_TRANSFER_NEED_DOWNLOAD)
       && (info->flags & GST_MAP_GL) == 0 && (info->flags & GST_MAP_READ) != 0) {
     gl->BindBuffer (mem->target, mem->id);

     if (gl->MapBufferRange) {
       /* FIXME: optionally remove this with a flag and return the
        * glMapBufferRange pointer (requires
        * GL_ARB_buffer_storage/GL4/GL_COHERENT_BIT) */
       guint gl_map_flags = GL_MAP_READ_BIT;

       data = gl->MapBufferRange (mem->target, 0, size, gl_map_flags);

       if (data)
         memcpy (mem->mem.data, data, size);

       gl->UnmapBuffer (mem->target);
       ret = mem->mem.data;
     } else if (gl->GetBufferSubData) {
       gl->GetBufferSubData (mem->target, 0, size, mem->mem.data);
       ret = mem->mem.data;
     } else {
       ret = NULL;
     }
     gl->BindBuffer (mem->target, 0);
   }

   return ret;
 }

 static void
 gst_gl_buffer_upload_cpu_write (GstGLBuffer * mem, GstMapInfo * info,
     gsize size)
 {
   const GstGLFuncs *gl = mem->mem.context->gl_vtable;
   gpointer data;

   if (!mem->mem.data)
     /* no data pointer has been written */
     return;

   /* The extra data pointer indirection/memcpy is needed for coherent across
    * concurrent map()'s in both GL and CPU */
   /* FIXME: uploading potentially half-written data for libav pushing READWRITE
    * mapped buffers */
   if (GST_MEMORY_FLAG_IS_SET (mem, GST_GL_BASE_MEMORY_TRANSFER_NEED_UPLOAD)
       || (mem->mem.map_flags & GST_MAP_WRITE) != 0) {
     gl->BindBuffer (mem->target, mem->id);

     if (gl->MapBufferRange) {
       /* FIXME: optionally remove this with a flag and return the
        * glMapBufferRange pointer (requires
        * GL_ARB_buffer_storage/GL4/GL_COHERENT_BIT) */
       guint gl_map_flags = GL_MAP_WRITE_BIT;

       data = gl->MapBufferRange (mem->target, 0, size, gl_map_flags);

       if (data)
         memcpy (data, mem->mem.data, size);

       gl->UnmapBuffer (mem->target);
     } else if (gl->BufferSubData) {
       gl->BufferSubData (mem->target, 0, size, mem->mem.data);
     }
     gl->BindBuffer (mem->target, 0);
   }
 }

 static gpointer
 _gl_buffer_map (GstGLBuffer * mem, GstMapInfo * info, gsize size)
 {
   const GstGLFuncs *gl = mem->mem.context->gl_vtable;

   if ((info->flags & GST_MAP_GL) != 0) {
     if (info->flags & GST_MAP_READ) {
       gst_gl_buffer_upload_cpu_write (mem, info, size);
     }
     gl->BindBuffer (mem->target, mem->id);
     return &mem->id;
   } else {
     return gst_gl_buffer_cpu_access (mem, info, size);
   }

   return NULL;
 }

 static void
 _gl_buffer_unmap (GstGLBuffer * mem, GstMapInfo * info)
 {
   const GstGLFuncs *gl = mem->mem.context->gl_vtable;

   if ((info->flags & GST_MAP_GL) != 0) {
     gl->BindBuffer (mem->target, 0);
   }
   /* XXX: optimistically transfer data */
 }

 /**
  * gst_gl_buffer_copy_buffer_sub_data:
  * @src: the source #GstGLBuffer
  * @dest: the destination #GstGLBuffer
  * @offset: the offset to copy from @src
  * @size: the size to copy from @src
  *
  * Copies @src into @dest using glCopyBufferSubData().
  *
  * Returns: whether the copy operation succeeded
  *
  * Since: 1.8
  */
 static gboolean
 gst_gl_buffer_copy_buffer_sub_data (GstGLBuffer * src,
     GstGLBuffer * dest, gssize offset, gssize size)
 {
   const GstGLFuncs *gl = src->mem.context->gl_vtable;
   GstMapInfo sinfo, dinfo;

   if (!gl->CopyBufferSubData)
     /* This is GL(ES) 3.0+ only */
     return FALSE;

   if (!gst_memory_map ((GstMemory *) src, &sinfo, GST_MAP_READ | GST_MAP_GL)) {
     GST_CAT_WARNING (GST_CAT_GL_BUFFER,
         "failed to read map source memory %p", src);
     return FALSE;
   }

   if (!gst_memory_map ((GstMemory *) dest, &dinfo, GST_MAP_WRITE | GST_MAP_GL)) {
     GST_CAT_WARNING (GST_CAT_GL_BUFFER,
         "failed to write map destination memory %p", dest);
     gst_memory_unmap ((GstMemory *) src, &sinfo);
     return FALSE;
   }

   gl->BindBuffer (GL_COPY_READ_BUFFER, src->id);
   gl->BindBuffer (GL_COPY_WRITE_BUFFER, dest->id);
   gl->CopyBufferSubData (GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER,
       offset, 0, size);

   gst_memory_unmap ((GstMemory *) src, &sinfo);
   gst_memory_unmap ((GstMemory *) dest, &dinfo);

   return TRUE;
 }

 static GstGLBuffer *
 _gl_buffer_copy (GstGLBuffer * src, gssize offset, gssize size)
 {
   GstAllocator *allocator = src->mem.mem.allocator;
   GstAllocationParams params = { 0, src->mem.mem.align, 0, 0 };
   GstGLBuffer *dest = NULL;

   dest = _gl_buffer_new (allocator, NULL, src->mem.context,
       src->target, src->usage_hints, &params, src->mem.mem.maxsize);

   /* If not doing a full copy, then copy to sysmem, the 2D represention of the
    * texture would become wrong */
   if (GST_MEMORY_FLAG_IS_SET (src, GST_GL_BASE_MEMORY_TRANSFER_NEED_UPLOAD)) {
     if (!gst_gl_base_memory_memcpy (GST_GL_BASE_MEMORY_CAST (src),
             GST_GL_BASE_MEMORY_CAST (dest), offset, size)) {
       GST_CAT_WARNING (GST_CAT_GL_BUFFER, "Could not copy GL Buffer");
       gst_memory_unref (GST_MEMORY_CAST (dest));
       dest = NULL;
     }
   } else {
     if (!gst_gl_buffer_copy_buffer_sub_data (src, dest, offset, size)) {
       if (!gst_gl_base_memory_memcpy (GST_GL_BASE_MEMORY_CAST (src),
               GST_GL_BASE_MEMORY_CAST (dest), offset, size)) {
         GST_CAT_WARNING (GST_CAT_GL_BUFFER, "Could not copy GL Buffer");
         gst_memory_unref (GST_MEMORY_CAST (dest));
         dest = NULL;
       }
     }
   }

   return dest;
 }

 static GstMemory *
 _gl_buffer_alloc (GstAllocator * allocator, gsize size,
     GstAllocationParams * params)
 {
   g_critical ("Need to use gst_gl_base_memory_alloc() to allocate from "
       "this allocator");

   return NULL;
 }

 static void
 _gl_buffer_destroy (GstGLBuffer * mem)
 {
   const GstGLFuncs *gl = mem->mem.context->gl_vtable;

   gl->DeleteBuffers (1, &mem->id);
 }

 static void
 _gst_gl_buffer_allocation_params_copy_data (GstGLBufferAllocationParams * src,
     GstGLBufferAllocationParams * dest)
 {
   memset (dest, 0, sizeof (*dest));

   gst_gl_allocation_params_copy_data (&src->parent, &dest->parent);

   dest->gl_target = src->gl_target;
   dest->gl_usage = src->gl_usage;
 }

 static void
 _gst_gl_buffer_allocation_params_free_data (GstGLBufferAllocationParams *
     params)
 {
   gst_gl_allocation_params_free_data (&params->parent);
 }

 /**
  * gst_gl_buffer_allocation_params_new:
  * @context: a #GstGLContext
  * @alloc_size: the size in bytes to allocate
  * @alloc_params: (allow-none): the #GstAllocationParams for @tex_id
  * @gl_target: the OpenGL target to allocate
  * @gl_usage: the OpenGL usage hint to allocate with
  *
  * Returns: a new #GstGLBufferAllocationParams for allocating OpenGL buffer
  *          objects
  *
  * Since: 1.8
  */
 GstGLBufferAllocationParams *
 gst_gl_buffer_allocation_params_new (GstGLContext * context, gsize alloc_size,
     GstAllocationParams * alloc_params, guint gl_target, guint gl_usage)
 {
   GstGLBufferAllocationParams *params;

   g_return_val_if_fail (GST_IS_GL_CONTEXT (context), NULL);
   g_return_val_if_fail (alloc_size > 0, NULL);

   params = g_new0 (GstGLBufferAllocationParams, 1);

   if (!gst_gl_allocation_params_init (&params->parent, sizeof (*params),
           GST_GL_ALLOCATION_PARAMS_ALLOC_FLAG_BUFFER |
           GST_GL_ALLOCATION_PARAMS_ALLOC_FLAG_ALLOC,
           (GstGLAllocationParamsCopyFunc)
           _gst_gl_buffer_allocation_params_copy_data,
           (GstGLAllocationParamsFreeFunc)
           _gst_gl_buffer_allocation_params_free_data, context, alloc_size,
           alloc_params, NULL, 0, NULL, NULL)) {
     g_free (params);
     return NULL;
   }

   params->gl_target = gl_target;
   params->gl_usage = gl_usage;

   return params;
 }

 static GstGLBuffer *
 _gl_buffer_alloc_mem (GstGLBufferAllocator * allocator,
     GstGLBufferAllocationParams * params)
 {
   guint alloc_flags = params->parent.alloc_flags;

   g_return_val_if_fail (alloc_flags &
       GST_GL_ALLOCATION_PARAMS_ALLOC_FLAG_BUFFER, NULL);
   g_return_val_if_fail (alloc_flags & GST_GL_ALLOCATION_PARAMS_ALLOC_FLAG_ALLOC,
       NULL);

   return _gl_buffer_new (GST_ALLOCATOR (allocator), NULL,
       params->parent.context, params->gl_target, params->gl_usage,
       params->parent.alloc_params, params->parent.alloc_size);
 }

 G_DEFINE_TYPE (GstGLBufferAllocator, gst_gl_buffer_allocator,
     GST_TYPE_GL_BASE_MEMORY_ALLOCATOR);

 static void
 gst_gl_buffer_allocator_class_init (GstGLBufferAllocatorClass * klass)
 {
   GstAllocatorClass *allocator_class = (GstAllocatorClass *) klass;
   GstGLBaseMemoryAllocatorClass *gl_base;

   gl_base = (GstGLBaseMemoryAllocatorClass *) klass;

   gl_base->alloc = (GstGLBaseMemoryAllocatorAllocFunction) _gl_buffer_alloc_mem;
   gl_base->create = (GstGLBaseMemoryAllocatorCreateFunction) _gl_buffer_create;
   gl_base->map = (GstGLBaseMemoryAllocatorMapFunction) _gl_buffer_map;
   gl_base->unmap = (GstGLBaseMemoryAllocatorUnmapFunction) _gl_buffer_unmap;
   gl_base->copy = (GstGLBaseMemoryAllocatorCopyFunction) _gl_buffer_copy;
   gl_base->destroy =
       (GstGLBaseMemoryAllocatorDestroyFunction) _gl_buffer_destroy;

   allocator_class->alloc = _gl_buffer_alloc;
 }

 static void
 gst_gl_buffer_allocator_init (GstGLBufferAllocator * allocator)
 {
   GstAllocator *alloc = GST_ALLOCATOR_CAST (allocator);

   alloc->mem_type = GST_GL_BUFFER_ALLOCATOR_NAME;

   GST_OBJECT_FLAG_SET (allocator, GST_ALLOCATOR_FLAG_CUSTOM_ALLOC);
 }

 /**
  * gst_gl_buffer_init_once:
  *
  * Initializes the GL Buffer allocator. It is safe to call this function
  * multiple times.  This must be called before any other #GstGLBuffer operation.
  *
  * Since: 1.8
  */
 void
 gst_gl_buffer_init_once (void)
 {
   static volatile gsize _init = 0;

   if (g_once_init_enter (&_init)) {
     gst_gl_base_memory_init_once ();

     GST_DEBUG_CATEGORY_INIT (GST_CAT_GL_BUFFER, "glbuffer", 0, "OpenGL Buffer");

     _gl_buffer_allocator =
         g_object_new (gst_gl_buffer_allocator_get_type (), NULL);

     gst_allocator_register (GST_GL_BUFFER_ALLOCATOR_NAME,
         gst_object_ref (_gl_buffer_allocator));
     g_once_init_leave (&_init, 1);
   }
 }

 /**
  * gst_is_gl_buffer:
  * @mem:a #GstMemory
  *
  * Returns: whether the memory at @mem is a #GstGLBuffer
  *
  * Since: 1.8
  */
 gboolean
 gst_is_gl_buffer (GstMemory * mem)
 {
   return mem != NULL && mem->allocator != NULL &&
       g_type_is_a (G_OBJECT_TYPE (mem->allocator),
       GST_TYPE_GL_BUFFER_ALLOCATOR);
 }
	/*
	* GStreamer
	* Copyright (C) 2015 Matthew Waters <matthew@centricular.com>
	*
	* This library is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Library General Public
	* License as published by the Free Software Foundation; either
	* version 2 of the License, or (at your option) any later version.
	*
	* This library 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
	* Library General Public License for more details.
	*
	* You should have received a copy of the GNU Library General Public
	* License along with this library; if not, write to the
	* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
	* Boston, MA 02110-1301, USA.
	*/

	#ifdef HAVE_CONFIG_H
	#include "config.h"
	#endif

	#include <string.h>

	#include "gstglbuffer.h"
	#include "gstglutils.h"

	/**
	* SECTION:gstglbuffer
	* @short_description: memory subclass for GL buffers
	* @see_also: #GstMemory, #GstAllocator
	*
	* GstGLBuffer is a #GstMemory subclass providing support for the mapping of
	* GL buffers.
	*
	* Data is uploaded or downloaded from the GPU as is necessary.
	*/

	/* Implementation notes:
	*
	* Currently does not take into account GLES2 differences (no mapbuffer)
	*/

	#define USING_OPENGL(context) (gst_gl_context_check_gl_version (context, GST_GL_API_OPENGL, 1, 0))
	#define USING_OPENGL3(context) (gst_gl_context_check_gl_version (context, GST_GL_API_OPENGL3, 3, 1))
	#define USING_GLES(context) (gst_gl_context_check_gl_version (context, GST_GL_API_GLES, 1, 0))
	#define USING_GLES2(context) (gst_gl_context_check_gl_version (context, GST_GL_API_GLES2, 2, 0))
	#define USING_GLES3(context) (gst_gl_context_check_gl_version (context, GST_GL_API_GLES2, 3, 0))

	/* compatibility definitions... */
	#ifndef GL_MAP_READ_BIT
	#define GL_MAP_READ_BIT 0x0001
	#endif
	#ifndef GL_MAP_WRITE_BIT
	#define GL_MAP_WRITE_BIT 0x0002
	#endif
	#ifndef GL_COPY_READ_BUFFER
	#define GL_COPY_READ_BUFFER 0x8F36
	#endif
	#ifndef GL_COPY_WRITE_BUFFER
	#define GL_COPY_WRITE_BUFFER 0x8F37
	#endif

	GST_DEBUG_CATEGORY_STATIC (GST_CAT_GL_BUFFER);
	#define GST_CAT_DEFUALT GST_CAT_GL_BUFFER

	static GstAllocator *_gl_buffer_allocator;

	static gboolean
	_gl_buffer_create (GstGLBuffer * gl_mem, GError ** error)
	{
	const GstGLFuncs *gl = gl_mem->mem.context->gl_vtable;

	gl->GenBuffers (1, &gl_mem->id);
	gl->BindBuffer (gl_mem->target, gl_mem->id);
	gl->BufferData (gl_mem->target, gl_mem->mem.mem.maxsize, NULL,
	gl_mem->usage_hints);
	gl->BindBuffer (gl_mem->target, 0);

	return TRUE;
	}

	struct create_data
	{
	GstGLBuffer *mem;
	gboolean result;
	};

	static void
	_gl_buffer_init (GstGLBuffer * mem, GstAllocator * allocator,
	GstMemory * parent, GstGLContext * context, guint gl_target, guint gl_usage,
	GstAllocationParams * params, gsize size)
	{
	mem->target = gl_target;
	mem->usage_hints = gl_usage;

	gst_gl_base_memory_init ((GstGLBaseMemory *) mem, allocator, parent, context,
	params, size, NULL, NULL);

	GST_CAT_DEBUG (GST_CAT_GL_BUFFER, "new GL buffer memory:%p size:%"
	G_GSIZE_FORMAT, mem, mem->mem.mem.maxsize);
	}

	static GstGLBuffer *
	_gl_buffer_new (GstAllocator * allocator, GstMemory * parent,
	GstGLContext * context, guint gl_target, guint gl_usage,
	GstAllocationParams * params, gsize size)
	{
	GstGLBuffer *ret = g_new0 (GstGLBuffer, 1);
	_gl_buffer_init (ret, allocator, parent, context, gl_target, gl_usage,
	params, size);

	return ret;
	}

	static gpointer
	gst_gl_buffer_cpu_access (GstGLBuffer * mem, GstMapInfo * info, gsize size)
	{
	const GstGLFuncs *gl = mem->mem.context->gl_vtable;
	gpointer data, ret;

	if (!gst_gl_base_memory_alloc_data (GST_GL_BASE_MEMORY_CAST (mem)))
	return NULL;

	ret = mem->mem.data;

	GST_CAT_LOG (GST_CAT_GL_BUFFER, "mapping id %d size %" G_GSIZE_FORMAT,
	mem->id, size);

	/* The extra data pointer indirection/memcpy is needed for coherent across
	* concurrent map()'s in both GL and CPU */
	if (GST_MEMORY_FLAG_IS_SET (mem, GST_GL_BASE_MEMORY_TRANSFER_NEED_DOWNLOAD)
	&& (info->flags & GST_MAP_GL) == 0 && (info->flags & GST_MAP_READ) != 0) {
	gl->BindBuffer (mem->target, mem->id);

	if (gl->MapBufferRange) {
	/* FIXME: optionally remove this with a flag and return the
	* glMapBufferRange pointer (requires
	* GL_ARB_buffer_storage/GL4/GL_COHERENT_BIT) */
	guint gl_map_flags = GL_MAP_READ_BIT;

	data = gl->MapBufferRange (mem->target, 0, size, gl_map_flags);

	if (data)
	memcpy (mem->mem.data, data, size);

	gl->UnmapBuffer (mem->target);
	ret = mem->mem.data;
	} else if (gl->GetBufferSubData) {
	gl->GetBufferSubData (mem->target, 0, size, mem->mem.data);
	ret = mem->mem.data;
	} else {
	ret = NULL;
	}
	gl->BindBuffer (mem->target, 0);
	}

	return ret;
	}

	static void
	gst_gl_buffer_upload_cpu_write (GstGLBuffer * mem, GstMapInfo * info,
	gsize size)
	{
	const GstGLFuncs *gl = mem->mem.context->gl_vtable;
	gpointer data;

	if (!mem->mem.data)
	/* no data pointer has been written */
	return;

	/* The extra data pointer indirection/memcpy is needed for coherent across
	* concurrent map()'s in both GL and CPU */
	/* FIXME: uploading potentially half-written data for libav pushing READWRITE
	* mapped buffers */
	if (GST_MEMORY_FLAG_IS_SET (mem, GST_GL_BASE_MEMORY_TRANSFER_NEED_UPLOAD)
	\|\| (mem->mem.map_flags & GST_MAP_WRITE) != 0) {
	gl->BindBuffer (mem->target, mem->id);

	if (gl->MapBufferRange) {
	/* FIXME: optionally remove this with a flag and return the
	* glMapBufferRange pointer (requires
	* GL_ARB_buffer_storage/GL4/GL_COHERENT_BIT) */
	guint gl_map_flags = GL_MAP_WRITE_BIT;

	data = gl->MapBufferRange (mem->target, 0, size, gl_map_flags);

	if (data)
	memcpy (data, mem->mem.data, size);

	gl->UnmapBuffer (mem->target);
	} else if (gl->BufferSubData) {
	gl->BufferSubData (mem->target, 0, size, mem->mem.data);
	}
	gl->BindBuffer (mem->target, 0);
	}
	}

	static gpointer
	_gl_buffer_map (GstGLBuffer * mem, GstMapInfo * info, gsize size)
	{
	const GstGLFuncs *gl = mem->mem.context->gl_vtable;

	if ((info->flags & GST_MAP_GL) != 0) {
	if (info->flags & GST_MAP_READ) {
	gst_gl_buffer_upload_cpu_write (mem, info, size);
	}
	gl->BindBuffer (mem->target, mem->id);
	return &mem->id;
	} else {
	return gst_gl_buffer_cpu_access (mem, info, size);
	}

	return NULL;
	}

	static void
	_gl_buffer_unmap (GstGLBuffer * mem, GstMapInfo * info)
	{
	const GstGLFuncs *gl = mem->mem.context->gl_vtable;

	if ((info->flags & GST_MAP_GL) != 0) {
	gl->BindBuffer (mem->target, 0);
	}
	/* XXX: optimistically transfer data */
	}

	/**
	* gst_gl_buffer_copy_buffer_sub_data:
	* @src: the source #GstGLBuffer
	* @dest: the destination #GstGLBuffer
	* @offset: the offset to copy from @src
	* @size: the size to copy from @src
	*
	* Copies @src into @dest using glCopyBufferSubData().
	*
	* Returns: whether the copy operation succeeded
	*
	* Since: 1.8
	*/
	static gboolean
	gst_gl_buffer_copy_buffer_sub_data (GstGLBuffer * src,
	GstGLBuffer * dest, gssize offset, gssize size)
	{
	const GstGLFuncs *gl = src->mem.context->gl_vtable;
	GstMapInfo sinfo, dinfo;

	if (!gl->CopyBufferSubData)
	/* This is GL(ES) 3.0+ only */
	return FALSE;

	if (!gst_memory_map ((GstMemory *) src, &sinfo, GST_MAP_READ \| GST_MAP_GL)) {
	GST_CAT_WARNING (GST_CAT_GL_BUFFER,
	"failed to read map source memory %p", src);
	return FALSE;
	}

	if (!gst_memory_map ((GstMemory *) dest, &dinfo, GST_MAP_WRITE \| GST_MAP_GL)) {
	GST_CAT_WARNING (GST_CAT_GL_BUFFER,
	"failed to write map destination memory %p", dest);
	gst_memory_unmap ((GstMemory *) src, &sinfo);
	return FALSE;
	}

	gl->BindBuffer (GL_COPY_READ_BUFFER, src->id);
	gl->BindBuffer (GL_COPY_WRITE_BUFFER, dest->id);
	gl->CopyBufferSubData (GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER,
	offset, 0, size);

	gst_memory_unmap ((GstMemory *) src, &sinfo);
	gst_memory_unmap ((GstMemory *) dest, &dinfo);

	return TRUE;
	}

	static GstGLBuffer *
	_gl_buffer_copy (GstGLBuffer * src, gssize offset, gssize size)
	{
	GstAllocator *allocator = src->mem.mem.allocator;
	GstAllocationParams params = { 0, src->mem.mem.align, 0, 0 };
	GstGLBuffer *dest = NULL;

	dest = _gl_buffer_new (allocator, NULL, src->mem.context,
	src->target, src->usage_hints, &params, src->mem.mem.maxsize);

	/* If not doing a full copy, then copy to sysmem, the 2D represention of the
	* texture would become wrong */
	if (GST_MEMORY_FLAG_IS_SET (src, GST_GL_BASE_MEMORY_TRANSFER_NEED_UPLOAD)) {
	if (!gst_gl_base_memory_memcpy (GST_GL_BASE_MEMORY_CAST (src),
	GST_GL_BASE_MEMORY_CAST (dest), offset, size)) {
	GST_CAT_WARNING (GST_CAT_GL_BUFFER, "Could not copy GL Buffer");
	gst_memory_unref (GST_MEMORY_CAST (dest));
	dest = NULL;
	}
	} else {
	if (!gst_gl_buffer_copy_buffer_sub_data (src, dest, offset, size)) {
	if (!gst_gl_base_memory_memcpy (GST_GL_BASE_MEMORY_CAST (src),
	GST_GL_BASE_MEMORY_CAST (dest), offset, size)) {
	GST_CAT_WARNING (GST_CAT_GL_BUFFER, "Could not copy GL Buffer");
	gst_memory_unref (GST_MEMORY_CAST (dest));
	dest = NULL;
	}
	}
	}

	return dest;
	}

	static GstMemory *
	_gl_buffer_alloc (GstAllocator * allocator, gsize size,
	GstAllocationParams * params)
	{
	g_critical ("Need to use gst_gl_base_memory_alloc() to allocate from "
	"this allocator");

	return NULL;
	}

	static void
	_gl_buffer_destroy (GstGLBuffer * mem)
	{
	const GstGLFuncs *gl = mem->mem.context->gl_vtable;

	gl->DeleteBuffers (1, &mem->id);
	}

	static void
	_gst_gl_buffer_allocation_params_copy_data (GstGLBufferAllocationParams * src,
	GstGLBufferAllocationParams * dest)
	{
	memset (dest, 0, sizeof (*dest));

	gst_gl_allocation_params_copy_data (&src->parent, &dest->parent);

	dest->gl_target = src->gl_target;
	dest->gl_usage = src->gl_usage;
	}

	static void
	_gst_gl_buffer_allocation_params_free_data (GstGLBufferAllocationParams *
	params)
	{
	gst_gl_allocation_params_free_data (&params->parent);
	}

	/**
	* gst_gl_buffer_allocation_params_new:
	* @context: a #GstGLContext
	* @alloc_size: the size in bytes to allocate
	* @alloc_params: (allow-none): the #GstAllocationParams for @tex_id
	* @gl_target: the OpenGL target to allocate
	* @gl_usage: the OpenGL usage hint to allocate with
	*
	* Returns: a new #GstGLBufferAllocationParams for allocating OpenGL buffer
	* objects
	*
	* Since: 1.8
	*/
	GstGLBufferAllocationParams *
	gst_gl_buffer_allocation_params_new (GstGLContext * context, gsize alloc_size,
	GstAllocationParams * alloc_params, guint gl_target, guint gl_usage)
	{
	GstGLBufferAllocationParams *params;

	g_return_val_if_fail (GST_IS_GL_CONTEXT (context), NULL);
	g_return_val_if_fail (alloc_size > 0, NULL);

	params = g_new0 (GstGLBufferAllocationParams, 1);

	if (!gst_gl_allocation_params_init (&params->parent, sizeof (*params),
	GST_GL_ALLOCATION_PARAMS_ALLOC_FLAG_BUFFER \|
	GST_GL_ALLOCATION_PARAMS_ALLOC_FLAG_ALLOC,
	(GstGLAllocationParamsCopyFunc)
	_gst_gl_buffer_allocation_params_copy_data,
	(GstGLAllocationParamsFreeFunc)
	_gst_gl_buffer_allocation_params_free_data, context, alloc_size,
	alloc_params, NULL, 0, NULL, NULL)) {
	g_free (params);
	return NULL;
	}

	params->gl_target = gl_target;
	params->gl_usage = gl_usage;

	return params;
	}

	static GstGLBuffer *
	_gl_buffer_alloc_mem (GstGLBufferAllocator * allocator,
	GstGLBufferAllocationParams * params)
	{
	guint alloc_flags = params->parent.alloc_flags;

	g_return_val_if_fail (alloc_flags &
	GST_GL_ALLOCATION_PARAMS_ALLOC_FLAG_BUFFER, NULL);
	g_return_val_if_fail (alloc_flags & GST_GL_ALLOCATION_PARAMS_ALLOC_FLAG_ALLOC,
	NULL);

	return _gl_buffer_new (GST_ALLOCATOR (allocator), NULL,
	params->parent.context, params->gl_target, params->gl_usage,
	params->parent.alloc_params, params->parent.alloc_size);
	}

	G_DEFINE_TYPE (GstGLBufferAllocator, gst_gl_buffer_allocator,
	GST_TYPE_GL_BASE_MEMORY_ALLOCATOR);

	static void
	gst_gl_buffer_allocator_class_init (GstGLBufferAllocatorClass * klass)
	{
	GstAllocatorClass allocator_class = (GstAllocatorClass ) klass;
	GstGLBaseMemoryAllocatorClass *gl_base;

	gl_base = (GstGLBaseMemoryAllocatorClass *) klass;

	gl_base->alloc = (GstGLBaseMemoryAllocatorAllocFunction) _gl_buffer_alloc_mem;
	gl_base->create = (GstGLBaseMemoryAllocatorCreateFunction) _gl_buffer_create;
	gl_base->map = (GstGLBaseMemoryAllocatorMapFunction) _gl_buffer_map;
	gl_base->unmap = (GstGLBaseMemoryAllocatorUnmapFunction) _gl_buffer_unmap;
	gl_base->copy = (GstGLBaseMemoryAllocatorCopyFunction) _gl_buffer_copy;
	gl_base->destroy =
	(GstGLBaseMemoryAllocatorDestroyFunction) _gl_buffer_destroy;

	allocator_class->alloc = _gl_buffer_alloc;
	}

	static void
	gst_gl_buffer_allocator_init (GstGLBufferAllocator * allocator)
	{
	GstAllocator *alloc = GST_ALLOCATOR_CAST (allocator);

	alloc->mem_type = GST_GL_BUFFER_ALLOCATOR_NAME;

	GST_OBJECT_FLAG_SET (allocator, GST_ALLOCATOR_FLAG_CUSTOM_ALLOC);
	}

	/**
	* gst_gl_buffer_init_once:
	*
	* Initializes the GL Buffer allocator. It is safe to call this function
	* multiple times. This must be called before any other #GstGLBuffer operation.
	*
	* Since: 1.8
	*/
	void
	gst_gl_buffer_init_once (void)
	{
	static volatile gsize _init = 0;

	if (g_once_init_enter (&_init)) {
	gst_gl_base_memory_init_once ();

	GST_DEBUG_CATEGORY_INIT (GST_CAT_GL_BUFFER, "glbuffer", 0, "OpenGL Buffer");

	_gl_buffer_allocator =
	g_object_new (gst_gl_buffer_allocator_get_type (), NULL);

	gst_allocator_register (GST_GL_BUFFER_ALLOCATOR_NAME,
	gst_object_ref (_gl_buffer_allocator));
	g_once_init_leave (&_init, 1);
	}
	}

	/**
	* gst_is_gl_buffer:
	* @mem:a #GstMemory
	*
	* Returns: whether the memory at @mem is a #GstGLBuffer
	*
	* Since: 1.8
	*/
	gboolean
	gst_is_gl_buffer (GstMemory * mem)
	{
	return mem != NULL && mem->allocator != NULL &&
	g_type_is_a (G_OBJECT_TYPE (mem->allocator),
	GST_TYPE_GL_BUFFER_ALLOCATOR);
	}