/*
 * GStreamer
 * Copyright (C) 2012-2014 Matthew Waters <ystree00@gmail.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 <stdio.h>

#include "gl.h"
#include "gstglupload.h"

#if GST_GL_HAVE_PLATFORM_EGL
#include "egl/gsteglimagememory.h"
#endif

/**
 * SECTION:gstglupload
 * @short_description: an object that uploads to GL textures
 * @see_also: #GstGLDownload, #GstGLMemory
 *
 * #GstGLUpload is an object that uploads data from system memory into GL textures.
 *
 * A #GstGLUpload can be created with gst_gl_upload_new()
 */

#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))

GST_DEBUG_CATEGORY_STATIC (gst_gl_upload_debug);
#define GST_CAT_DEFAULT gst_gl_upload_debug

typedef struct _UploadMethod UploadMethod;

struct _GstGLUploadPrivate
{
  GstVideoInfo in_info;
  GstVideoInfo out_info;
  GstCaps *in_caps;
  GstCaps *out_caps;

  GstGLColorConvert *convert;

  GstBuffer *outbuf;

  UploadMethod *method;
  gpointer method_impl;
  int method_i;
};

typedef enum
{
  GST_GL_UPLOAD_DONE = 1,
  GST_GL_UPLOAD_CONVERT_GL_MEMORY = 2,

  GST_GL_UPLOAD_ERROR = -1,
  GST_GL_UPLOAD_UNSUPPORTED = -2,
  GST_GL_UPLOAD_UNSHARED_GL_CONTEXT = 3,
} GstGLUploadReturn;

typedef enum
{
  METHOD_FLAG_CAN_SHARE_CONTEXT = 1,
} GstGLUploadMethodFlags;

struct _UploadMethod
{
  const gchar *name;
  GstGLUploadMethodFlags flags;

    gpointer (*new) (GstGLUpload * upload);
    gboolean (*accept) (gpointer impl, GstBuffer * buffer, GstCaps * in_caps,
      GstCaps * out_caps);
    GstGLUploadReturn (*perform) (gpointer impl, GstBuffer * buffer,
      GstBuffer ** outbuf);
  void (*release) (gpointer impl, GstBuffer * buffer);
  void (*free) (gpointer impl);
} _UploadMethod;

struct GLMemoryUpload
{
  GstGLUpload *upload;
};

static gpointer
_gl_memory_upload_new (GstGLUpload * upload)
{
  struct GLMemoryUpload *mem = g_new0 (struct GLMemoryUpload, 1);

  mem->upload = upload;

  return mem;
}

static gboolean
_gl_memory_upload_accept (gpointer impl, GstBuffer * buffer, GstCaps * in_caps,
    GstCaps * out_caps)
{
  struct GLMemoryUpload *upload = impl;
  GstCapsFeatures *features, *gl_features;
  gboolean ret = TRUE;
  int i;

  gl_features =
      gst_caps_features_from_string (GST_CAPS_FEATURE_MEMORY_GL_MEMORY);

  features = gst_caps_get_features (in_caps, 0);
  if (!gst_caps_features_is_equal (features, gl_features))
    ret = FALSE;

  features = gst_caps_get_features (out_caps, 0);
  if (!gst_caps_features_is_equal (features, gl_features))
    ret = FALSE;

  gst_caps_features_free (gl_features);

  if (!ret)
    return FALSE;

  if (gst_buffer_n_memory (buffer) !=
      GST_VIDEO_INFO_N_PLANES (&upload->upload->priv->in_info))
    return FALSE;

  for (i = 0; i < GST_VIDEO_INFO_N_PLANES (&upload->upload->priv->in_info); i++) {
    GstMemory *mem = gst_buffer_peek_memory (buffer, i);

    if (!gst_is_gl_memory (mem))
      return FALSE;
  }

  return TRUE;
}

static GstGLUploadReturn
_gl_memory_upload_perform (gpointer impl, GstBuffer * buffer,
    GstBuffer ** outbuf)
{
  struct GLMemoryUpload *upload = impl;
  GstGLMemory *gl_mem;
  int i;

  for (i = 0; i < GST_VIDEO_INFO_N_PLANES (&upload->upload->priv->in_info); i++) {
    GstMemory *mem = gst_buffer_peek_memory (buffer, i);

    gl_mem = (GstGLMemory *) mem;
    if (!gst_gl_context_can_share (upload->upload->context, gl_mem->context))
      return GST_GL_UPLOAD_UNSHARED_GL_CONTEXT;
  }

  *outbuf = gst_buffer_ref (buffer);

  return GST_GL_UPLOAD_CONVERT_GL_MEMORY;
}

static void
_gl_memory_upload_release (gpointer impl, GstBuffer * buffer)
{
}

static void
_gl_memory_upload_free (gpointer impl)
{
  g_free (impl);
}

static UploadMethod _gl_memory_upload = {
  "GLMemory",
  METHOD_FLAG_CAN_SHARE_CONTEXT,
  &_gl_memory_upload_new,
  &_gl_memory_upload_accept,
  &_gl_memory_upload_perform,
  &_gl_memory_upload_release,
  &_gl_memory_upload_free
};

#if GST_GL_HAVE_PLATFORM_EGL
struct EGLImageUpload
{
  GstGLUpload *upload;
};

static gpointer
_egl_image_upload_new (GstGLUpload * upload)
{
  struct EGLImageUpload *image = g_new0 (struct EGLImageUpload, 1);

  image->upload = upload;

  return image;
}

static gboolean
_egl_image_upload_accept (gpointer impl, GstBuffer * buffer, GstCaps * in_caps,
    GstCaps * out_caps)
{
  struct EGLImageUpload *image = impl;
  GstCapsFeatures *features, *gl_features;
  gboolean ret = TRUE;
  int i;

  gl_features =
      gst_caps_features_from_string (GST_CAPS_FEATURE_MEMORY_EGL_IMAGE);
  features = gst_caps_get_features (in_caps, 0);
  if (!gst_caps_features_is_equal (features, gl_features))
    ret = FALSE;

  gst_caps_features_free (gl_features);

  gl_features =
      gst_caps_features_from_string (GST_CAPS_FEATURE_MEMORY_GL_MEMORY);
  features = gst_caps_get_features (out_caps, 0);
  if (!gst_caps_features_is_equal (features, gl_features))
    ret = FALSE;

  gst_caps_features_free (gl_features);

  if (!ret)
    return FALSE;

  if (gst_buffer_n_memory (buffer) !=
      GST_VIDEO_INFO_N_PLANES (&image->upload->priv->in_info))
    return FALSE;

  for (i = 0; i < GST_VIDEO_INFO_N_PLANES (&image->upload->priv->in_info); i++) {
    GstMemory *mem = gst_buffer_peek_memory (buffer, i);

    if (!gst_is_egl_image_memory (mem))
      return FALSE;
  }

  return TRUE;
}

static GstGLUploadReturn
_egl_image_upload_perform (gpointer impl, GstBuffer * buffer,
    GstBuffer ** outbuf)
{
  struct EGLImageUpload *image = impl;
  guint i;

  /* FIXME: buffer pool */
  *outbuf = gst_buffer_new ();
  gst_gl_memory_setup_buffer (image->upload->context,
      &image->upload->priv->out_info, NULL, *outbuf);

  for (i = 0; i < GST_VIDEO_INFO_N_PLANES (&image->upload->priv->in_info); i++) {
    GstMemory *mem = gst_buffer_peek_memory (buffer, i);
    GstGLMemory *out_gl_mem =
        (GstGLMemory *) gst_buffer_peek_memory (*outbuf, i);
    const GstGLFuncs *gl = NULL;

    gl = GST_GL_CONTEXT (((GstEGLImageMemory *) mem)->context)->gl_vtable;

    gl->ActiveTexture (GL_TEXTURE0 + i);
    gl->BindTexture (GL_TEXTURE_2D, out_gl_mem->tex_id);
    gl->EGLImageTargetTexture2D (GL_TEXTURE_2D,
        gst_egl_image_memory_get_image (mem));
  }

  if (GST_IS_GL_BUFFER_POOL (buffer->pool))
    gst_gl_buffer_pool_replace_last_buffer (GST_GL_BUFFER_POOL (buffer->pool),
        buffer);

  return GST_GL_UPLOAD_CONVERT_GL_MEMORY;
}

static void
_egl_image_upload_release (gpointer impl, GstBuffer * buffer)
{
}

static void
_egl_image_upload_free (gpointer impl)
{
  g_free (impl);
}

static UploadMethod _egl_image_upload = {
  "EGLImage",
  0,
  &_egl_image_upload_new,
  &_egl_image_upload_accept,
  &_egl_image_upload_perform,
  &_egl_image_upload_release,
  &_egl_image_upload_free
};
#endif

struct GLUploadMeta
{
  GstGLUpload *upload;

  gboolean result;
  GstVideoGLTextureUploadMeta *meta;
  guint texture_ids[GST_VIDEO_MAX_PLANES];
};

static gpointer
_upload_meta_upload_new (GstGLUpload * upload)
{
  struct GLUploadMeta *meta = g_new0 (struct GLUploadMeta, 1);

  meta->upload = upload;

  return meta;
}

static gboolean
_upload_meta_upload_accept (gpointer impl, GstBuffer * buffer,
    GstCaps * in_caps, GstCaps * out_caps)
{
  struct GLUploadMeta *upload = impl;
  GstCapsFeatures *features, *gl_features;
  GstVideoGLTextureUploadMeta *meta;
  gboolean ret = TRUE;

  features = gst_caps_get_features (in_caps, 0);
  gl_features =
      gst_caps_features_from_string
      (GST_CAPS_FEATURE_META_GST_VIDEO_GL_TEXTURE_UPLOAD_META);

  if (!gst_caps_features_is_equal (features, gl_features))
    ret = FALSE;

  gst_caps_features_free (gl_features);

  if ((meta = gst_buffer_get_video_gl_texture_upload_meta (buffer)) == NULL)
    return FALSE;

  gl_features =
      gst_caps_features_from_string (GST_CAPS_FEATURE_MEMORY_GL_MEMORY);
  features = gst_caps_get_features (out_caps, 0);
  if (!gst_caps_features_is_equal (features, gl_features))
    ret = FALSE;

  gst_caps_features_free (gl_features);

  if (!ret)
    return ret;

  if (meta->texture_type[0] != GST_VIDEO_GL_TEXTURE_TYPE_RGBA) {
    GST_FIXME_OBJECT (upload, "only single rgba texture supported");
    return FALSE;
  }

  if (meta->texture_orientation !=
      GST_VIDEO_GL_TEXTURE_ORIENTATION_X_NORMAL_Y_NORMAL) {
    GST_FIXME_OBJECT (upload, "only x-normal, y-normal textures supported");
    return FALSE;
  }

  return TRUE;
}

/*
 * Uploads using gst_video_gl_texture_upload_meta_upload().
 * i.e. consumer of GstVideoGLTextureUploadMeta
 */
static void
_do_upload_with_meta (GstGLContext * context, struct GLUploadMeta *upload)
{
  if (!gst_video_gl_texture_upload_meta_upload (upload->meta,
          upload->texture_ids)) {
    upload->result = FALSE;
    return;
  }

  upload->result = TRUE;
}

static GstGLUploadReturn
_upload_meta_upload_perform (gpointer impl, GstBuffer * buffer,
    GstBuffer ** outbuf)
{
  struct GLUploadMeta *upload = impl;
  int i;

  GST_LOG_OBJECT (upload, "Attempting upload with GstVideoGLTextureUploadMeta");

  upload->meta = gst_buffer_get_video_gl_texture_upload_meta (buffer);

  /* FIXME: buffer pool */
  *outbuf = gst_buffer_new ();
  gst_gl_memory_setup_buffer (upload->upload->context,
      &upload->upload->priv->in_info, NULL, *outbuf);

  for (i = 0; i < GST_VIDEO_MAX_PLANES; i++) {
    guint tex_id = 0;

    if (i < GST_VIDEO_INFO_N_PLANES (&upload->upload->priv->in_info)) {
      GstMemory *mem = gst_buffer_peek_memory (*outbuf, i);
      tex_id = ((GstGLMemory *) mem)->tex_id;
    }

    upload->texture_ids[i] = tex_id;
  }

  GST_LOG ("Uploading with GLTextureUploadMeta with textures %i,%i,%i,%i",
      upload->texture_ids[0], upload->texture_ids[1], upload->texture_ids[2],
      upload->texture_ids[3]);

  gst_gl_context_thread_add (upload->upload->context,
      (GstGLContextThreadFunc) _do_upload_with_meta, upload);

  if (!upload->result)
    return GST_GL_UPLOAD_ERROR;

  return GST_GL_UPLOAD_CONVERT_GL_MEMORY;
}

static void
_upload_meta_upload_release (gpointer impl, GstBuffer * buffer)
{
}

static void
_upload_meta_upload_free (gpointer impl)
{
  struct GLUploadMeta *upload = impl;
  gint i;

  for (i = 0; i < GST_VIDEO_MAX_PLANES; i++) {
    if (upload->texture_ids[i])
      gst_gl_context_del_texture (upload->upload->context,
          &upload->texture_ids[i]);
  }
  g_free (upload);
}

static UploadMethod _upload_meta_upload = {
  "UploadMeta",
  METHOD_FLAG_CAN_SHARE_CONTEXT,
  &_upload_meta_upload_new,
  &_upload_meta_upload_accept,
  &_upload_meta_upload_perform,
  &_upload_meta_upload_release,
  &_upload_meta_upload_free
};

struct RawUpload
{
  GstGLUpload *upload;
  GstGLMemory *in_tex[GST_VIDEO_MAX_PLANES];
  GstVideoFrame in_frame;
};

static gpointer
_raw_data_upload_new (GstGLUpload * upload)
{
  struct RawUpload *raw = g_new0 (struct RawUpload, 1);

  raw->upload = upload;

  return raw;
}

static gboolean
_raw_data_upload_accept (gpointer impl, GstBuffer * buffer, GstCaps * in_caps,
    GstCaps * out_caps)
{
  struct RawUpload *raw = impl;
  GstCapsFeatures *features, *gl_features;
  gboolean ret = TRUE;

  gl_features =
      gst_caps_features_from_string (GST_CAPS_FEATURE_MEMORY_GL_MEMORY);
  features = gst_caps_get_features (out_caps, 0);
  if (!gst_caps_features_is_equal (features, gl_features))
    ret = FALSE;

  gst_caps_features_free (gl_features);

  if (!ret)
    return ret;

  if (!gst_video_frame_map (&raw->in_frame, &raw->upload->priv->in_info, buffer,
          GST_MAP_READ))
    return FALSE;

  raw->upload->priv->in_info = raw->in_frame.info;

  return TRUE;
}

static GstGLUploadReturn
_raw_data_upload_perform (gpointer impl, GstBuffer * buffer,
    GstBuffer ** outbuf)
{
  struct RawUpload *raw = impl;
  int i;

  if (!raw->in_tex[0])
    gst_gl_memory_setup_wrapped (raw->upload->context,
        &raw->upload->priv->in_info, NULL, raw->in_frame.data, raw->in_tex);

  for (i = 0; i < GST_VIDEO_MAX_PLANES; i++) {
    if (raw->in_tex[i]) {
      raw->in_tex[i]->data = raw->in_frame.data[i];
      GST_GL_MEMORY_FLAG_SET (raw->in_tex[i], GST_GL_MEMORY_FLAG_NEED_UPLOAD);
    }
  }

  *outbuf = gst_buffer_new ();
  for (i = 0; i < GST_VIDEO_INFO_N_PLANES (&raw->upload->priv->in_info); i++) {
    gst_buffer_append_memory (*outbuf,
        gst_memory_ref ((GstMemory *) raw->in_tex[i]));
  }

  return GST_GL_UPLOAD_CONVERT_GL_MEMORY;
}

static void
_raw_data_upload_release (gpointer impl, GstBuffer * buffer)
{
  struct RawUpload *raw = impl;

  gst_video_frame_unmap (&raw->in_frame);
}

static void
_raw_data_upload_free (gpointer impl)
{
  struct RawUpload *raw = impl;
  int i;

  for (i = 0; i < GST_VIDEO_MAX_PLANES; i++) {
    if (raw->in_tex[i])
      gst_memory_unref ((GstMemory *) raw->in_tex[i]);
  }
  g_free (raw);
}

static UploadMethod _raw_data_upload = {
  "Raw Data",
  0,
  &_raw_data_upload_new,
  &_raw_data_upload_accept,
  &_raw_data_upload_perform,
  &_raw_data_upload_release,
  &_raw_data_upload_free
};

static UploadMethod *upload_methods[] = { &_gl_memory_upload,
#if GST_GL_HAVE_PLATFORM_EGL
  &_egl_image_upload,
#endif
  &_upload_meta_upload, &_raw_data_upload
};

#define DEBUG_INIT \
  GST_DEBUG_CATEGORY_INIT (gst_gl_upload_debug, "glupload", 0, "upload");

G_DEFINE_TYPE_WITH_CODE (GstGLUpload, gst_gl_upload, GST_TYPE_OBJECT,
    DEBUG_INIT);
static void gst_gl_upload_finalize (GObject * object);
static void gst_gl_upload_release_buffer_unlocked (GstGLUpload * upload);

#define GST_GL_UPLOAD_GET_PRIVATE(obj) (G_TYPE_INSTANCE_GET_PRIVATE ((obj), \
    GST_TYPE_GL_UPLOAD, GstGLUploadPrivate))

static void
gst_gl_upload_class_init (GstGLUploadClass * klass)
{
  g_type_class_add_private (klass, sizeof (GstGLUploadPrivate));

  G_OBJECT_CLASS (klass)->finalize = gst_gl_upload_finalize;
}

static void
gst_gl_upload_init (GstGLUpload * upload)
{
  upload->priv = GST_GL_UPLOAD_GET_PRIVATE (upload);
}

/**
 * gst_gl_upload_new:
 * @context: a #GstGLContext
 *
 * Returns: a new #GstGLUpload object
 */
GstGLUpload *
gst_gl_upload_new (GstGLContext * context)
{
  GstGLUpload *upload = g_object_new (GST_TYPE_GL_UPLOAD, NULL);

  upload->context = gst_object_ref (context);

  return upload;
}

static void
gst_gl_upload_finalize (GObject * object)
{
  GstGLUpload *upload;

  upload = GST_GL_UPLOAD (object);

  gst_gl_upload_release_buffer_unlocked (upload);

  if (upload->priv->method_impl)
    upload->priv->method->free (upload->priv->method_impl);
  upload->priv->method_i = 0;

  if (upload->context) {
    gst_object_unref (upload->context);
    upload->context = NULL;
  }

  if (upload->priv->convert) {
    gst_object_unref (upload->priv->convert);
    upload->priv->convert = NULL;
  }

  if (upload->priv->in_caps) {
    gst_caps_unref (upload->priv->in_caps);
    upload->priv->in_caps = NULL;
  }

  if (upload->priv->out_caps) {
    gst_caps_unref (upload->priv->out_caps);
    upload->priv->out_caps = NULL;
  }

  G_OBJECT_CLASS (gst_gl_upload_parent_class)->finalize (object);
}

static gboolean
_gst_gl_upload_set_caps_unlocked (GstGLUpload * upload, GstCaps * in_caps,
    GstCaps * out_caps)
{
  g_return_val_if_fail (upload != NULL, FALSE);
  g_return_val_if_fail (gst_caps_is_fixed (in_caps), FALSE);

  if (upload->priv->in_caps && upload->priv->out_caps
      && gst_caps_is_equal (upload->priv->in_caps, in_caps)
      && gst_caps_is_equal (upload->priv->out_caps, out_caps))
    return TRUE;

  gst_caps_replace (&upload->priv->in_caps, in_caps);
  gst_caps_replace (&upload->priv->out_caps, out_caps);

  gst_video_info_from_caps (&upload->priv->in_info, in_caps);
  gst_video_info_from_caps (&upload->priv->out_info, out_caps);

  if (upload->priv->method_impl)
    upload->priv->method->free (upload->priv->method_impl);
  upload->priv->method_impl = NULL;
  upload->priv->method_i = 0;

  return TRUE;
}

/**
 * gst_gl_upload_set_caps:
 * @upload: a #GstGLUpload
 * @in_caps: input #GstCaps
 * @out_caps: output #GstCaps
 *
 * Initializes @upload with the information required for upload.
 *
 * Returns: whether @in_caps and @out_caps could be set on @upload
 */
gboolean
gst_gl_upload_set_caps (GstGLUpload * upload, GstCaps * in_caps,
    GstCaps * out_caps)
{
  gboolean ret;

  GST_OBJECT_LOCK (upload);
  ret = _gst_gl_upload_set_caps_unlocked (upload, in_caps, out_caps);
  GST_OBJECT_UNLOCK (upload);

  return ret;
}

/**
 * gst_gl_upload_get_caps:
 * @upload: a #GstGLUpload
 * @in_caps: (transfer full): (allow-none): (out): the input #GstCaps
 * @ou_caps: (transfer full): (allow-none): (out): the output #GstCaps
 *
 * Returns: (transfer none): The #GstCaps set by gst_gl_upload_set_caps()
 */
void
gst_gl_upload_get_caps (GstGLUpload * upload, GstCaps ** in_caps,
    GstCaps ** out_caps)
{
  GST_OBJECT_LOCK (upload);
  if (in_caps)
    *in_caps =
        upload->priv->in_caps ? gst_caps_ref (upload->priv->in_caps) : NULL;
  if (out_caps)
    *out_caps =
        upload->priv->out_caps ? gst_caps_ref (upload->priv->out_caps) : NULL;
  GST_OBJECT_UNLOCK (upload);
}

static void
gst_gl_upload_release_buffer_unlocked (GstGLUpload * upload)
{
  if (upload->priv->outbuf && upload->priv->method_impl) {
    upload->priv->method->release (upload->priv->method_impl,
        upload->priv->outbuf);
    gst_buffer_replace (&upload->priv->outbuf, NULL);
  }
}

/**
 * gst_gl_upload_release_buffer:
 * @upload: a #GstGLUpload
 *
 * Releases any buffers currently referenced by @upload
 */
void
gst_gl_upload_release_buffer (GstGLUpload * upload)
{
  g_return_if_fail (upload != NULL);

  GST_OBJECT_LOCK (upload);
  gst_gl_upload_release_buffer_unlocked (upload);
  GST_OBJECT_UNLOCK (upload);
}

static gboolean
_upload_find_method (GstGLUpload * upload)
{
  if (upload->priv->method_i >= G_N_ELEMENTS (upload_methods))
    return FALSE;

  if (upload->priv->method_impl)
    upload->priv->method->free (upload->priv->method_impl);

  upload->priv->method = upload_methods[upload->priv->method_i];
  upload->priv->method_impl = upload->priv->method->new (upload);

  GST_DEBUG_OBJECT (upload, "attempting upload with uploader %s",
      upload->priv->method->name);

  upload->priv->method_i++;

  return TRUE;
}

/**
 * gst_gl_upload_perform_with_buffer:
 * @upload: a #GstGLUpload
 * @buffer: a #GstBuffer
 * @outbuf_ptr: (allow-none): resulting buffer
 *
 * Uploads @buffer to the texture given by @tex_id.  @tex_id is valid
 * until gst_gl_upload_release_buffer() is called.
 *
 * Returns: whether the upload was successful
 */
gboolean
gst_gl_upload_perform_with_buffer (GstGLUpload * upload, GstBuffer * buffer,
    GstBuffer ** outbuf_ptr)
{
  GstGLUploadReturn ret;

  g_return_val_if_fail (GST_IS_GL_UPLOAD (upload), FALSE);
  g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);

  GST_OBJECT_LOCK (upload);

  gst_gl_upload_release_buffer_unlocked (upload);

#define NEXT_METHOD \
do { \
  if (!_upload_find_method (upload)) { \
    GST_OBJECT_UNLOCK (upload); \
    return FALSE; \
  } \
  goto restart; \
} while (0)

  if (!upload->priv->method_impl)
    _upload_find_method (upload);

restart:
  if (!upload->priv->method->accept (upload->priv->method_impl, buffer,
          upload->priv->in_caps, upload->priv->out_caps))
    NEXT_METHOD;

  ret =
      upload->priv->method->perform (upload->priv->method_impl, buffer,
      &upload->priv->outbuf);
  if (ret == GST_GL_UPLOAD_UNSHARED_GL_CONTEXT) {
    upload->priv->method->free (upload->priv->method_impl);
    upload->priv->method = &_raw_data_upload;
    upload->priv->method_impl = upload->priv->method->new (upload);
    goto restart;
  } else if (ret == GST_GL_UPLOAD_CONVERT_GL_MEMORY) {
    GstBuffer *outbuf;

    if (!upload->priv->convert)
      upload->priv->convert = gst_gl_color_convert_new (upload->context);
    gst_gl_color_convert_set_format (upload->priv->convert,
        &upload->priv->in_info, &upload->priv->out_info);

    if (!(outbuf = gst_gl_color_convert_perform (upload->priv->convert,
                upload->priv->outbuf))) {
      gst_gl_upload_release_buffer_unlocked (upload);
      NEXT_METHOD;
    }

    gst_buffer_unref (upload->priv->outbuf);
    upload->priv->outbuf = outbuf;
  } else if (ret == GST_GL_UPLOAD_DONE) {
    /* we are done */
  } else {
    gst_gl_upload_release_buffer_unlocked (upload);
    upload->priv->method->free (upload->priv->method_impl);
    NEXT_METHOD;
  }

  if (outbuf_ptr)
    *outbuf_ptr = gst_buffer_ref (upload->priv->outbuf);

  GST_OBJECT_UNLOCK (upload);

  return upload->priv->outbuf != NULL;

#undef NEXT_METHOD
}