static gboolean
gst_gl_video_mixer_init_shader (GstGLMixer * mixer, GstCaps * outcaps)
{
  GstGLVideoMixer *video_mixer = GST_GL_VIDEO_MIXER (mixer);

  if (video_mixer->shader)
    gst_gl_context_del_shader (GST_GL_BASE_MIXER (mixer)->context,
        video_mixer->shader);

  return gst_gl_context_gen_shader (GST_GL_BASE_MIXER (mixer)->context,
      video_mixer_v_src, video_mixer_f_src, &video_mixer->shader);
}
static gboolean
_draw_checker_background (GstGLVideoMixer * video_mixer)
{
  GstGLMixer *mixer = GST_GL_MIXER (video_mixer);
  const GstGLFuncs *gl = GST_GL_BASE_MIXER (mixer)->context->gl_vtable;
  gint attr_position_loc = 0;

  /* *INDENT-OFF* */
  gfloat v_vertices[] = {
    -1.0,-1.0,-1.0f,
     1.0,-1.0,-1.0f,
     1.0, 1.0,-1.0f,
    -1.0, 1.0,-1.0f,
  };
  /* *INDENT-ON* */

  if (!video_mixer->checker) {
    if (!gst_gl_context_gen_shader (GST_GL_BASE_MIXER (mixer)->context,
            checker_v_src, checker_f_src, &video_mixer->checker))
      return FALSE;
  }

  gst_gl_shader_use (video_mixer->checker);
  attr_position_loc =
      gst_gl_shader_get_attribute_location (video_mixer->checker, "a_position");

  _init_vbo_indices (video_mixer);

  if (!video_mixer->checker_vbo) {
    gl->GenBuffers (1, &video_mixer->checker_vbo);
    gl->BindBuffer (GL_ARRAY_BUFFER, video_mixer->checker_vbo);
    gl->BufferData (GL_ARRAY_BUFFER, 4 * 3 * sizeof (GLfloat), v_vertices,
        GL_STATIC_DRAW);
  } else {
    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, video_mixer->vbo_indices);
    gl->BindBuffer (GL_ARRAY_BUFFER, video_mixer->checker_vbo);
  }

  gl->VertexAttribPointer (attr_position_loc, 3, GL_FLOAT,
      GL_FALSE, 3 * sizeof (GLfloat), (void *) 0);

  gl->EnableVertexAttribArray (attr_position_loc);

  gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0);

  gl->DisableVertexAttribArray (attr_position_loc);
  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
  gl->BindBuffer (GL_ARRAY_BUFFER, 0);

  return TRUE;
}
/* Convert to caps that can be accepted by this element... */
static GstCaps *
get_converted_caps (GstGLStereoMix * mix, GstCaps * caps)
{
#if 0
  GstGLContext *context = GST_GL_BASE_MIXER (mix)->context;
  GstCaps *result, *tmp;

  GST_LOG_OBJECT (mix, "Converting caps %" GST_PTR_FORMAT, caps);
  result = gst_gl_upload_transform_caps (context, GST_PAD_SINK, caps, NULL);
  tmp = result;
  GST_TRACE_OBJECT (mix, "transfer returned caps %" GST_PTR_FORMAT, tmp);

  result =
      gst_gl_color_convert_transform_caps (context, GST_PAD_SINK, tmp, NULL);
  gst_caps_unref (tmp);
  GST_TRACE_OBJECT (mix, "convert returned caps %" GST_PTR_FORMAT, tmp);

  tmp = result;
  result = gst_gl_view_convert_transform_caps (mix->viewconvert,
      GST_PAD_SINK, tmp, NULL);
  gst_caps_unref (tmp);
#else
  GstCaps *result;

  GST_LOG_OBJECT (mix, "Converting caps %" GST_PTR_FORMAT, caps);
  result = gst_gl_view_convert_transform_caps (mix->viewconvert,
      GST_PAD_SINK, caps, NULL);
#endif

  GST_LOG_OBJECT (mix, "returning caps %" GST_PTR_FORMAT, result);

  return result;
}
static gboolean
_draw_background (GstGLVideoMixer * video_mixer)
{
  GstGLMixer *mixer = GST_GL_MIXER (video_mixer);
  const GstGLFuncs *gl = GST_GL_BASE_MIXER (mixer)->context->gl_vtable;

  switch (video_mixer->background) {
    case GST_GL_VIDEO_MIXER_BACKGROUND_BLACK:
      gl->ClearColor (0.0, 0.0, 0.0, 1.0);
      gl->Clear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
      break;
    case GST_GL_VIDEO_MIXER_BACKGROUND_WHITE:
      gl->ClearColor (1.0, 1.0, 1.0, 1.0);
      gl->Clear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
      break;
    case GST_GL_VIDEO_MIXER_BACKGROUND_TRANSPARENT:
      gl->ClearColor (0.0, 0.0, 0.0, 0.0);
      gl->Clear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
      break;
    case GST_GL_VIDEO_MIXER_BACKGROUND_CHECKER:
      return _draw_checker_background (video_mixer);
      break;
    default:
      break;
  }

  return TRUE;
}
/* Called after videoaggregator fixates our caps */
static gboolean
_negotiated_caps (GstAggregator * agg, GstCaps * caps)
{
  GstVideoAggregator *vagg = GST_VIDEO_AGGREGATOR (agg);
  GstGLStereoMix *mix = GST_GL_STEREO_MIX (vagg);
  GstCaps *in_caps;

  GST_LOG_OBJECT (mix, "Configured output caps %" GST_PTR_FORMAT, caps);

  if (GST_AGGREGATOR_CLASS (parent_class)->negotiated_src_caps)
    if (!GST_AGGREGATOR_CLASS (parent_class)->negotiated_src_caps (agg, caps))
      return FALSE;

  /* Update the glview_convert output */

  /* We can configure the view_converter now */
  gst_gl_view_convert_set_context (mix->viewconvert,
      GST_GL_BASE_MIXER (mix)->context);

  in_caps = gst_video_info_to_caps (&mix->mix_info);
  gst_caps_set_features (in_caps, 0,
      gst_caps_features_from_string (GST_CAPS_FEATURE_MEMORY_GL_MEMORY));
  gst_caps_set_simple (in_caps, "texture-target", G_TYPE_STRING,
      GST_GL_TEXTURE_TARGET_2D_STR, NULL);

  gst_gl_view_convert_set_caps (mix->viewconvert, in_caps, caps);

  return TRUE;
}
static gboolean
_negotiated_caps (GstVideoAggregator * vagg, GstCaps * caps)
{
    GstGLBaseMixer *mix = GST_GL_BASE_MIXER (vagg);

    return gst_gl_base_mixer_do_bufferpool (mix, caps);
}
static gboolean
gst_gl_mosaic_init_shader (GstGLMixer * mixer, GstCaps * outcaps)
{
  GstGLMosaic *mosaic = GST_GL_MOSAIC (mixer);

  g_clear_object (&mosaic->shader);
  //blocking call, wait the opengl thread has compiled the shader
  return gst_gl_context_gen_shader (GST_GL_BASE_MIXER (mixer)->context,
      mosaic_v_src, mosaic_f_src, &mosaic->shader);
}
static void
_init_vbo_indices (GstGLVideoMixer * mixer)
{
  const GstGLFuncs *gl = GST_GL_BASE_MIXER (mixer)->context->gl_vtable;

  if (!mixer->vbo_indices) {
    gl->GenBuffers (1, &mixer->vbo_indices);
    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, mixer->vbo_indices);
    gl->BufferData (GL_ELEMENT_ARRAY_BUFFER, sizeof (indices), indices,
        GL_STATIC_DRAW);
  }
}
static gboolean
_reset_pad_gl (GstAggregator * agg, GstAggregatorPad * aggpad, gpointer udata)
{
  const GstGLFuncs *gl = GST_GL_BASE_MIXER (agg)->context->gl_vtable;
  GstGLVideoMixerPad *pad = GST_GL_VIDEO_MIXER_PAD (aggpad);

  if (pad->vertex_buffer) {
    gl->DeleteBuffers (1, &pad->vertex_buffer);
    pad->vertex_buffer = 0;
  }

  return FALSE;
}
static gboolean
gst_gl_mosaic_process_textures (GstGLMixer * mix, GstGLMemory * out_tex)
{
  GstGLMosaic *mosaic = GST_GL_MOSAIC (mix);
  GstGLContext *context = GST_GL_BASE_MIXER (mix)->context;

  mosaic->out_tex = out_tex;

  gst_gl_context_thread_add (context, (GstGLContextThreadFunc) _mosaic_render,
      mosaic);

  return TRUE;
}
示例#11
0
static void
gst_gl_video_mixer_reset (GstGLMixer * mixer)
{
  GstGLVideoMixer *video_mixer = GST_GL_VIDEO_MIXER (mixer);
  GstGLContext *context = GST_GL_BASE_MIXER (mixer)->context;

  video_mixer->input_frames = NULL;

  GST_DEBUG_OBJECT (mixer, "context:%p", context);

  if (video_mixer->shader)
    gst_gl_context_del_shader (context, video_mixer->shader);
  video_mixer->shader = NULL;

  if (video_mixer->checker)
    gst_gl_context_del_shader (context, video_mixer->checker);
  video_mixer->checker = NULL;

  if (GST_GL_BASE_MIXER (mixer)->context)
    gst_gl_context_thread_add (context, (GstGLContextThreadFunc) _reset_gl,
        mixer);
}
static gboolean
gst_gl_base_mixer_src_query (GstAggregator * agg, GstQuery * query)
{
    gboolean res = FALSE;
    GstGLBaseMixer *mix = GST_GL_BASE_MIXER (agg);
    GstGLBaseMixerClass *mix_class = GST_GL_BASE_MIXER_GET_CLASS (mix);

    switch (GST_QUERY_TYPE (query)) {
    case GST_QUERY_CONTEXT:
    {
        const gchar *context_type;
        GstContext *context, *old_context;

        res = gst_gl_handle_context_query ((GstElement *) mix, query,
                                           &mix->display, &mix->priv->other_context);
        if (mix->display)
            gst_gl_display_filter_gl_api (mix->display,
                                          mix_class->supported_gl_api);
        gst_query_parse_context_type (query, &context_type);

        if (g_strcmp0 (context_type, "gst.gl.local_context") == 0) {
            GstStructure *s;

            gst_query_parse_context (query, &old_context);

            if (old_context)
                context = gst_context_copy (old_context);
            else
                context = gst_context_new ("gst.gl.local_context", FALSE);

            s = gst_context_writable_structure (context);
            gst_structure_set (s, "context", GST_GL_TYPE_CONTEXT, mix->context,
                               NULL);
            gst_query_set_context (query, context);
            gst_context_unref (context);

            res = mix->context != NULL;
        }
        GST_LOG_OBJECT (mix, "context query of type %s %i", context_type, res);

        if (res)
            return res;

        break;
    }
    default:
        break;
    }

    return GST_AGGREGATOR_CLASS (parent_class)->src_query (agg, query);
}
static void
gst_gl_base_mixer_set_context (GstElement * element, GstContext * context)
{
    GstGLBaseMixer *mix = GST_GL_BASE_MIXER (element);
    GstGLBaseMixerClass *mix_class = GST_GL_BASE_MIXER_GET_CLASS (mix);

    gst_gl_handle_set_context (element, context, &mix->display,
                               &mix->priv->other_context);

    if (mix->display)
        gst_gl_display_filter_gl_api (mix->display, mix_class->supported_gl_api);

    GST_ELEMENT_CLASS (parent_class)->set_context (element, context);
}
static void
gst_gl_base_mixer_get_property (GObject * object,
                                guint prop_id, GValue * value, GParamSpec * pspec)
{
    GstGLBaseMixer *mixer = GST_GL_BASE_MIXER (object);

    switch (prop_id) {
    case PROP_CONTEXT:
        g_value_set_object (value, mixer->context);
        break;
    default:
        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
        break;
    }
}
示例#15
0
static gboolean
gst_gl_video_mixer_process_textures (GstGLMixer * mix, GPtrArray * frames,
    guint out_tex)
{
  GstGLVideoMixer *video_mixer = GST_GL_VIDEO_MIXER (mix);

  video_mixer->input_frames = frames;

  gst_gl_context_use_fbo_v2 (GST_GL_BASE_MIXER (mix)->context,
      GST_VIDEO_INFO_WIDTH (&GST_VIDEO_AGGREGATOR (mix)->info),
      GST_VIDEO_INFO_HEIGHT (&GST_VIDEO_AGGREGATOR (mix)->info),
      mix->fbo, mix->depthbuffer,
      out_tex, gst_gl_video_mixer_callback, (gpointer) video_mixer);

  return TRUE;
}
static GstStateChangeReturn
gst_gl_base_mixer_change_state (GstElement * element, GstStateChange transition)
{
    GstGLBaseMixer *mix = GST_GL_BASE_MIXER (element);
    GstGLBaseMixerClass *mix_class = GST_GL_BASE_MIXER_GET_CLASS (mix);
    GstStateChangeReturn ret = GST_STATE_CHANGE_SUCCESS;

    GST_DEBUG_OBJECT (mix, "changing state: %s => %s",
                      gst_element_state_get_name (GST_STATE_TRANSITION_CURRENT (transition)),
                      gst_element_state_get_name (GST_STATE_TRANSITION_NEXT (transition)));

    switch (transition) {
    case GST_STATE_CHANGE_NULL_TO_READY:
        if (!gst_gl_ensure_element_data (element, &mix->display,
                                         &mix->priv->other_context))
            return GST_STATE_CHANGE_FAILURE;

        gst_gl_display_filter_gl_api (mix->display, mix_class->supported_gl_api);
        break;
    default:
        break;
    }

    ret = GST_ELEMENT_CLASS (parent_class)->change_state (element, transition);
    if (ret == GST_STATE_CHANGE_FAILURE)
        return ret;

    switch (transition) {
    case GST_STATE_CHANGE_READY_TO_NULL:
        if (mix->priv->other_context) {
            gst_object_unref (mix->priv->other_context);
            mix->priv->other_context = NULL;
        }

        if (mix->display) {
            gst_object_unref (mix->display);
            mix->display = NULL;
        }
        break;
    default:
        break;
    }

    return ret;
}
示例#17
0
static void
_reset_gl (GstGLContext * context, GstGLVideoMixer * video_mixer)
{
  const GstGLFuncs *gl = GST_GL_BASE_MIXER (video_mixer)->context->gl_vtable;

  if (video_mixer->vao) {
    gl->DeleteVertexArrays (1, &video_mixer->vao);
    video_mixer->vao = 0;
  }

  if (video_mixer->vbo_indices) {
    gl->DeleteBuffers (1, &video_mixer->vbo_indices);
    video_mixer->vbo_indices = 0;
  }

  gst_aggregator_iterate_sinkpads (GST_AGGREGATOR (video_mixer), _reset_pad_gl,
      NULL);
}
static gboolean
gst_gl_base_mixer_src_activate_mode (GstAggregator * aggregator,
                                     GstPadMode mode, gboolean active)
{
    GstGLBaseMixer *mix;
    gboolean result = FALSE;

    mix = GST_GL_BASE_MIXER (aggregator);

    switch (mode) {
    case GST_PAD_MODE_PUSH:
    case GST_PAD_MODE_PULL:
        result = gst_gl_base_mixer_activate (mix, active);
        break;
    default:
        result = TRUE;
        break;
    }
    return result;
}
static gboolean
gst_gl_base_mixer_stop (GstAggregator * agg)
{
    GstGLBaseMixer *mix = GST_GL_BASE_MIXER (agg);

    if (mix->priv->query) {
        gst_query_unref (mix->priv->query);
        mix->priv->query = NULL;
    }

    if (mix->priv->pool) {
        gst_object_unref (mix->priv->pool);
        mix->priv->pool = NULL;
    }

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

    gst_gl_base_mixer_reset (mix);

    return TRUE;
}
示例#20
0
/* opengl scene, params: input texture (not the output mixer->texture) */
static void
gst_gl_video_mixer_callback (gpointer stuff)
{
  GstGLVideoMixer *video_mixer = GST_GL_VIDEO_MIXER (stuff);
  GstVideoAggregator *vagg = GST_VIDEO_AGGREGATOR (stuff);
  GstGLMixer *mixer = GST_GL_MIXER (video_mixer);
  GstGLFuncs *gl = GST_GL_BASE_MIXER (mixer)->context->gl_vtable;

  GLint attr_position_loc = 0;
  GLint attr_texture_loc = 0;
  guint out_width, out_height;

  guint count = 0;

  out_width = GST_VIDEO_INFO_WIDTH (&vagg->info);
  out_height = GST_VIDEO_INFO_HEIGHT (&vagg->info);

  gst_gl_context_clear_shader (GST_GL_BASE_MIXER (mixer)->context);
  gl->BindTexture (GL_TEXTURE_2D, 0);

  gl->Disable (GL_DEPTH_TEST);
  gl->Disable (GL_CULL_FACE);

  if (gl->GenVertexArrays) {
    if (!video_mixer->vao)
      gl->GenVertexArrays (1, &video_mixer->vao);
    gl->BindVertexArray (video_mixer->vao);
  }

  if (!_draw_background (video_mixer))
    return;

  gst_gl_shader_use (video_mixer->shader);

  attr_position_loc =
      gst_gl_shader_get_attribute_location (video_mixer->shader, "a_position");
  attr_texture_loc =
      gst_gl_shader_get_attribute_location (video_mixer->shader, "a_texCoord");

  gl->Enable (GL_BLEND);

  while (count < video_mixer->input_frames->len) {
    GstGLMixerFrameData *frame;
    GstGLVideoMixerPad *pad;
    GstVideoInfo *v_info;
    guint in_tex;
    guint in_width, in_height;

    /* *INDENT-OFF* */
    gfloat v_vertices[] = {
      -1.0,-1.0,-1.0f, 0.0f, 0.0f,
       1.0,-1.0,-1.0f, 1.0f, 0.0f,
       1.0, 1.0,-1.0f, 1.0f, 1.0f,
      -1.0, 1.0,-1.0f, 0.0f, 1.0f,
    };
    /* *INDENT-ON* */

    frame = g_ptr_array_index (video_mixer->input_frames, count);
    if (!frame) {
      GST_DEBUG ("skipping texture, null frame");
      count++;
      continue;
    }
    pad = (GstGLVideoMixerPad *) frame->pad;
    v_info = &GST_VIDEO_AGGREGATOR_PAD (pad)->info;
    in_width = GST_VIDEO_INFO_WIDTH (v_info);
    in_height = GST_VIDEO_INFO_HEIGHT (v_info);

    if (!frame->texture || in_width <= 0 || in_height <= 0
        || pad->alpha == 0.0f) {
      GST_DEBUG ("skipping texture:%u frame:%p width:%u height:%u alpha:%f",
          frame->texture, frame, in_width, in_height, pad->alpha);
      count++;
      continue;
    }

    in_tex = frame->texture;

    _init_vbo_indices (video_mixer);

    if (pad->geometry_change || !pad->vertex_buffer) {
      gint pad_width, pad_height;
      gfloat w, h;

      _mixer_pad_get_output_size (video_mixer, pad, &pad_width, &pad_height);

      w = ((gfloat) pad_width / (gfloat) out_width);
      h = ((gfloat) pad_height / (gfloat) out_height);

      /* top-left */
      v_vertices[0] = v_vertices[15] =
          2.0f * (gfloat) pad->xpos / (gfloat) out_width - 1.0f;
      /* bottom-left */
      v_vertices[1] = v_vertices[6] =
          2.0f * (gfloat) pad->ypos / (gfloat) out_height - 1.0f;
      /* top-right */
      v_vertices[5] = v_vertices[10] = v_vertices[0] + 2.0f * w;
      /* bottom-right */
      v_vertices[11] = v_vertices[16] = v_vertices[1] + 2.0f * h;
      GST_TRACE ("processing texture:%u dimensions:%ux%u, at %f,%f %fx%f with "
          "alpha:%f", in_tex, in_width, in_height, v_vertices[0], v_vertices[1],
          v_vertices[5], v_vertices[11], pad->alpha);

      if (!pad->vertex_buffer)
        gl->GenBuffers (1, &pad->vertex_buffer);

      gl->BindBuffer (GL_ARRAY_BUFFER, pad->vertex_buffer);

      gl->BufferData (GL_ARRAY_BUFFER, 4 * 5 * sizeof (GLfloat), v_vertices,
          GL_STATIC_DRAW);

      pad->geometry_change = FALSE;
    } else {
      gl->BindBuffer (GL_ARRAY_BUFFER, pad->vertex_buffer);
    }
    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, video_mixer->vbo_indices);

    gl->BlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    gl->BlendEquation (GL_FUNC_ADD);

    gl->ActiveTexture (GL_TEXTURE0);
    gl->BindTexture (GL_TEXTURE_2D, in_tex);
    gst_gl_shader_set_uniform_1i (video_mixer->shader, "texture", 0);
    gst_gl_shader_set_uniform_1f (video_mixer->shader, "alpha", pad->alpha);

    gl->EnableVertexAttribArray (attr_position_loc);
    gl->EnableVertexAttribArray (attr_texture_loc);

    gl->VertexAttribPointer (attr_position_loc, 3, GL_FLOAT,
        GL_FALSE, 5 * sizeof (GLfloat), (void *) 0);

    gl->VertexAttribPointer (attr_texture_loc, 2, GL_FLOAT,
        GL_FALSE, 5 * sizeof (GLfloat), (void *) (3 * sizeof (GLfloat)));

    gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0);

    ++count;
  }

  gl->DisableVertexAttribArray (attr_position_loc);
  gl->DisableVertexAttribArray (attr_texture_loc);

  if (gl->GenVertexArrays)
    gl->BindVertexArray (0);

  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
  gl->BindBuffer (GL_ARRAY_BUFFER, 0);
  gl->BindTexture (GL_TEXTURE_2D, 0);

  gl->Disable (GL_BLEND);

  gst_gl_context_clear_shader (GST_GL_BASE_MIXER (mixer)->context);
}
/* opengl scene, params: input texture (not the output mixer->texture) */
static gboolean
gst_gl_mosaic_callback (gpointer stuff)
{
  GstGLMosaic *mosaic = GST_GL_MOSAIC (stuff);
  GstGLMixer *mixer = GST_GL_MIXER (mosaic);
  GstGLFuncs *gl = GST_GL_BASE_MIXER (mixer)->context->gl_vtable;
  GList *walk;

  static GLfloat xrot = 0;
  static GLfloat yrot = 0;
  static GLfloat zrot = 0;

  GLint attr_position_loc = 0;
  GLint attr_texture_loc = 0;

  const GLfloat matrix[] = {
    0.5f, 0.0f, 0.0f, 0.0f,
    0.0f, 0.5f, 0.0f, 0.0f,
    0.0f, 0.0f, 0.5f, 0.0f,
    0.0f, 0.0f, 0.0f, 1.0f
  };
  const GLushort indices[] = {
    0, 1, 2,
    0, 2, 3
  };

  guint count = 0;

  gst_gl_context_clear_shader (GST_GL_BASE_MIXER (mixer)->context);
  gl->BindTexture (GL_TEXTURE_2D, 0);

  gl->Enable (GL_DEPTH_TEST);

  gl->ClearColor (0.0, 0.0, 0.0, 0.0);
  gl->Clear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

  gst_gl_shader_use (mosaic->shader);

  attr_position_loc =
      gst_gl_shader_get_attribute_location (mosaic->shader, "a_position");
  attr_texture_loc =
      gst_gl_shader_get_attribute_location (mosaic->shader, "a_texCoord");

  GST_OBJECT_LOCK (mosaic);
  walk = GST_ELEMENT (mosaic)->sinkpads;
  while (walk) {
    GstGLMixerPad *pad = walk->data;
    /* *INDENT-OFF* */
    gfloat v_vertices[] = {
      /* front face */
       1.0f, 1.0f,-1.0f, 1.0f, 0.0f,
       1.0f,-1.0f,-1.0f, 1.0f, 1.0f,
      -1.0f,-1.0f,-1.0f, 0.0f, 1.0f,
      -1.0f, 1.0f,-1.0f, 0.0f, 0.0f,
      /* right face */
       1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
       1.0f,-1.0f, 1.0f, 0.0f, 0.0f,
       1.0f,-1.0f,-1.0f, 0.0f, 1.0f,
       1.0f, 1.0f,-1.0f, 1.0f, 1.0f,
      /* left face */
      -1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
      -1.0f, 1.0f,-1.0f, 1.0f, 1.0f,
      -1.0f,-1.0f,-1.0f, 0.0f, 1.0f,
      -1.0f,-1.0f, 1.0f, 0.0f, 0.0f,
      /* top face */
       1.0f,-1.0f, 1.0f, 1.0f, 0.0f,
      -1.0f,-1.0f, 1.0f, 0.0f, 0.0f,
      -1.0f,-1.0f,-1.0f, 0.0f, 1.0f,
       1.0f,-1.0f,-1.0f, 1.0f, 1.0f,
      /* bottom face */
       1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
       1.0f, 1.0f,-1.0f, 1.0f, 1.0f,
      -1.0f, 1.0f,-1.0f, 0.0f, 1.0f,
      -1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
      /* back face */
       1.0f, 1.0f, 1.0f, 1.0f, 0.0f,
      -1.0f, 1.0f, 1.0f, 0.0f, 0.0f,
      -1.0f,-1.0f, 1.0f, 0.0f, 1.0f,
       1.0f,-1.0f, 1.0f, 1.0f, 1.0f
    };
    /* *INDENT-ON* */
    guint in_tex;
    guint width, height;

    in_tex = pad->current_texture;
    width = GST_VIDEO_INFO_WIDTH (&GST_VIDEO_AGGREGATOR_PAD (pad)->info);
    height = GST_VIDEO_INFO_HEIGHT (&GST_VIDEO_AGGREGATOR_PAD (pad)->info);

    if (!in_tex || width <= 0 || height <= 0) {
      GST_DEBUG ("skipping texture:%u pad:%p width:%u height %u",
          in_tex, pad, width, height);
      count++;
      walk = g_list_next (walk);
      continue;
    }

    GST_TRACE ("processing texture:%u dimensions:%ux%u", in_tex, width, height);

    gl->VertexAttribPointer (attr_position_loc, 3, GL_FLOAT,
        GL_FALSE, 5 * sizeof (GLfloat), &v_vertices[5 * 4 * count]);

    gl->VertexAttribPointer (attr_texture_loc, 2, GL_FLOAT,
        GL_FALSE, 5 * sizeof (GLfloat), &v_vertices[5 * 4 * count + 3]);

    gl->EnableVertexAttribArray (attr_position_loc);
    gl->EnableVertexAttribArray (attr_texture_loc);

    gl->ActiveTexture (GL_TEXTURE0);
    gl->BindTexture (GL_TEXTURE_2D, in_tex);
    gst_gl_shader_set_uniform_1i (mosaic->shader, "s_texture", 0);
    gst_gl_shader_set_uniform_1f (mosaic->shader, "xrot_degree", xrot);
    gst_gl_shader_set_uniform_1f (mosaic->shader, "yrot_degree", yrot);
    gst_gl_shader_set_uniform_1f (mosaic->shader, "zrot_degree", zrot);
    gst_gl_shader_set_uniform_matrix_4fv (mosaic->shader, "u_matrix", 1,
        GL_FALSE, matrix);

    gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices);

    ++count;

    walk = g_list_next (walk);
  }
  GST_OBJECT_UNLOCK (mosaic);

  gl->DisableVertexAttribArray (attr_position_loc);
  gl->DisableVertexAttribArray (attr_texture_loc);

  gl->BindTexture (GL_TEXTURE_2D, 0);

  gl->Disable (GL_DEPTH_TEST);

  gst_gl_context_clear_shader (GST_GL_BASE_MIXER (mixer)->context);

  xrot += 0.6f;
  yrot += 0.4f;
  zrot += 0.8f;

  return TRUE;
}
static gboolean
gst_gl_base_mixer_sink_query (GstAggregator * agg, GstAggregatorPad * bpad,
                              GstQuery * query)
{
    gboolean ret = FALSE;
    GstGLBaseMixer *mix = GST_GL_BASE_MIXER (agg);
    GstGLBaseMixerClass *mix_class = GST_GL_BASE_MIXER_GET_CLASS (mix);
    GstGLBaseMixerPad *pad = GST_GL_BASE_MIXER_PAD (bpad);

    GST_TRACE ("QUERY %" GST_PTR_FORMAT, query);

    switch (GST_QUERY_TYPE (query)) {
    case GST_QUERY_ALLOCATION:
    {
        GstQuery *decide_query = NULL;

        GST_OBJECT_LOCK (mix);
        if (G_UNLIKELY (!mix->priv->negotiated)) {
            GST_DEBUG_OBJECT (mix,
                              "not negotiated yet, can't answer ALLOCATION query");
            GST_OBJECT_UNLOCK (mix);
            return FALSE;
        }
        if ((decide_query = mix->priv->query))
            gst_query_ref (decide_query);
        GST_OBJECT_UNLOCK (mix);

        GST_DEBUG_OBJECT (mix,
                          "calling propose allocation with query %" GST_PTR_FORMAT,
                          decide_query);

        /* pass the query to the propose_allocation vmethod if any */
        if (mix_class->propose_allocation)
            ret = mix_class->propose_allocation (mix, pad, decide_query, query);
        else
            ret = FALSE;

        if (decide_query)
            gst_query_unref (decide_query);

        GST_DEBUG_OBJECT (mix, "ALLOCATION ret %d, %" GST_PTR_FORMAT, ret, query);
        return ret;
    }
    case GST_QUERY_CONTEXT:
    {
        const gchar *context_type;
        GstContext *context, *old_context;

        ret = gst_gl_handle_context_query ((GstElement *) mix, query,
                                           &mix->display, &mix->priv->other_context);
        if (mix->display)
            gst_gl_display_filter_gl_api (mix->display,
                                          mix_class->supported_gl_api);
        gst_query_parse_context_type (query, &context_type);

        if (g_strcmp0 (context_type, "gst.gl.local_context") == 0) {
            GstStructure *s;

            gst_query_parse_context (query, &old_context);

            if (old_context)
                context = gst_context_copy (old_context);
            else
                context = gst_context_new ("gst.gl.local_context", FALSE);

            s = gst_context_writable_structure (context);
            gst_structure_set (s, "context", GST_GL_TYPE_CONTEXT, mix->context,
                               NULL);
            gst_query_set_context (query, context);
            gst_context_unref (context);

            ret = mix->context != NULL;
        }
        GST_LOG_OBJECT (mix, "context query of type %s %i", context_type, ret);

        if (ret)
            return ret;

        break;
    }
    default:
        break;
    }

    return GST_AGGREGATOR_CLASS (parent_class)->sink_query (agg, bpad, query);;
}