From 65c57b77ff9d362a8bf4305fffd324bff65c4909 Mon Sep 17 00:00:00 2001
From: Matthew Waters <matthew@centricular.com>
Date: Fri, 1 May 2015 12:04:28 +1000
Subject: [PATCH] gl: element buffers are part of vao state

Use them as such.  They are also required for GL3 core profile support
with glDrawElements on OS X.
---
 ext/gl/gstglfiltercube.c            | 49 ++++++++++++++++++++++++-------------
 ext/gl/gstglfiltercube.h            |  1 +
 ext/gl/gstglimagesink.c             | 36 ++++++++++++++++++++-------
 ext/gl/gstglimagesink.h             |  1 +
 ext/gl/gstgloverlay.c               | 48 +++++++++++++++++++++++++-----------
 ext/gl/gstgloverlay.h               |  1 +
 ext/gl/gstgltransformation.c        | 21 +++++++++++++---
 ext/gl/gstgltransformation.h        |  1 +
 ext/gl/gstglvideomixer.c            | 41 ++++++++++++++++++++++---------
 ext/gl/gstglvideomixer.h            |  1 +
 gst-libs/gst/gl/gstglcolorconvert.c | 20 ++++++---------
 gst-libs/gst/gl/gstglfilter.c       | 23 ++++++++++++++---
 gst-libs/gst/gl/gstglfilter.h       |  1 +
 13 files changed, 174 insertions(+), 70 deletions(-)

diff --git a/ext/gl/gstglfiltercube.c b/ext/gl/gstglfiltercube.c
index ad529b3..d389310 100644
--- a/ext/gl/gstglfiltercube.c
+++ b/ext/gl/gstglfiltercube.c
@@ -293,6 +293,11 @@ gst_gl_filter_cube_reset_gl (GstGLFilter * filter)
     cube_filter->vertex_buffer = 0;
   }
 
+  if (cube_filter->vbo_indices) {
+    gl->DeleteBuffers (1, &cube_filter->vbo_indices);
+    cube_filter->vbo_indices = 0;
+  }
+
   if (cube_filter->shader) {
     gst_gl_context_del_shader (GST_GL_BASE_FILTER (filter)->context,
         cube_filter->shader);
@@ -380,6 +385,21 @@ static const GLfloat vertices[] = {
     -1.0,  1.0, -1.0, 0.0, 1.0,
     -1.0,  1.0,  1.0, 0.0, 0.0
 };
+
+static const GLushort indices[] = {
+    0, 1, 2,
+    0, 2, 3,
+    4, 5, 6,
+    4, 6, 7,
+    8, 9, 10,
+    8, 10, 11,
+    12, 13, 14,
+    12, 14, 15,
+    16, 17, 18,
+    16, 18, 19,
+    20, 21, 22,
+    20, 22, 23
+};
 /* *INDENT-ON* */
 
 static void
@@ -387,6 +407,7 @@ _bind_buffer (GstGLFilterCube * cube_filter)
 {
   const GstGLFuncs *gl = GST_GL_BASE_FILTER (cube_filter)->context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, cube_filter->vbo_indices);
   gl->BindBuffer (GL_ARRAY_BUFFER, cube_filter->vertex_buffer);
 
   cube_filter->attr_position =
@@ -412,6 +433,7 @@ _unbind_buffer (GstGLFilterCube * cube_filter)
 {
   const GstGLFuncs *gl = GST_GL_BASE_FILTER (cube_filter)->context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
   gl->BindBuffer (GL_ARRAY_BUFFER, 0);
 
   gl->DisableVertexAttribArray (cube_filter->attr_position);
@@ -429,21 +451,6 @@ _callback (gpointer stuff)
   static GLfloat yrot = 0;
   static GLfloat zrot = 0;
 
-  GLushort indices[] = {
-    0, 1, 2,
-    0, 2, 3,
-    4, 5, 6,
-    4, 6, 7,
-    8, 9, 10,
-    8, 10, 11,
-    12, 13, 14,
-    12, 14, 15,
-    16, 17, 18,
-    16, 18, 19,
-    20, 21, 22,
-    20, 22, 23
-  };
-
   const GLfloat matrix[] = {
     0.5f, 0.0f, 0.0f, 0.0f,
     0.0f, 0.5f, 0.0f, 0.0f,
@@ -478,10 +485,18 @@ _callback (gpointer stuff)
     gl->BufferData (GL_ARRAY_BUFFER, 6 * 4 * 5 * sizeof (GLfloat), vertices,
         GL_STATIC_DRAW);
 
+    gl->GenBuffers (1, &cube_filter->vbo_indices);
+    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, cube_filter->vbo_indices);
+    gl->BufferData (GL_ELEMENT_ARRAY_BUFFER, sizeof (indices), indices,
+        GL_STATIC_DRAW);
+
     if (gl->GenVertexArrays) {
       _bind_buffer (cube_filter);
-      gl->BindBuffer (GL_ARRAY_BUFFER, 0);
+      gl->BindVertexArray (0);
     }
+
+    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
+    gl->BindBuffer (GL_ARRAY_BUFFER, 0);
   }
 
   if (gl->GenVertexArrays)
@@ -489,7 +504,7 @@ _callback (gpointer stuff)
   else
     _bind_buffer (cube_filter);
 
-  gl->DrawElements (GL_TRIANGLES, 36, GL_UNSIGNED_SHORT, indices);
+  gl->DrawElements (GL_TRIANGLES, 36, GL_UNSIGNED_SHORT, 0);
 
   if (gl->GenVertexArrays)
     gl->BindVertexArray (0);
diff --git a/ext/gl/gstglfiltercube.h b/ext/gl/gstglfiltercube.h
index 6850f00..88b51a6 100644
--- a/ext/gl/gstglfiltercube.h
+++ b/ext/gl/gstglfiltercube.h
@@ -54,6 +54,7 @@ struct _GstGLFilterCube
 
     guint              in_tex;
     GLuint             vao;
+    GLuint             vbo_indices;
     GLuint             vertex_buffer;
     GLint              attr_position;
     GLint              attr_texture;
diff --git a/ext/gl/gstglimagesink.c b/ext/gl/gstglimagesink.c
index 0315bfd..6cec51b 100644
--- a/ext/gl/gstglimagesink.c
+++ b/ext/gl/gstglimagesink.c
@@ -1348,6 +1348,8 @@ static const GLfloat vertices[] = {
     -1.0f, -1.0f, 0.0f, 0.0f, 1.0f,
      1.0f, -1.0f, 0.0f, 1.0f, 1.0f
 };
+
+static const GLushort indices[] = { 0, 1, 2, 0, 2, 3 };
 /* *INDENT-ON* */
 
 static void
@@ -1355,9 +1357,8 @@ _bind_buffer (GstGLImageSink * gl_sink)
 {
   const GstGLFuncs *gl = gl_sink->context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, gl_sink->vbo_indices);
   gl->BindBuffer (GL_ARRAY_BUFFER, gl_sink->vertex_buffer);
-  gl->BufferData (GL_ARRAY_BUFFER, 4 * 5 * sizeof (GLfloat), vertices,
-      GL_STATIC_DRAW);
 
   /* Load the vertex position */
   gl->VertexAttribPointer (gl_sink->attr_position, 3, GL_FLOAT, GL_FALSE,
@@ -1376,6 +1377,7 @@ _unbind_buffer (GstGLImageSink * gl_sink)
 {
   const GstGLFuncs *gl = gl_sink->context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
   gl->BindBuffer (GL_ARRAY_BUFFER, 0);
 
   gl->DisableVertexAttribArray (gl_sink->attr_position);
@@ -1400,15 +1402,27 @@ gst_glimage_sink_thread_init_redisplay (GstGLImageSink * gl_sink)
     gl->BindVertexArray (gl_sink->vao);
   }
 
-  gl->GenBuffers (1, &gl_sink->vertex_buffer);
-  _bind_buffer (gl_sink);
+  if (!gl_sink->vertex_buffer) {
+    gl->GenBuffers (1, &gl_sink->vertex_buffer);
+    gl->BindBuffer (GL_ARRAY_BUFFER, gl_sink->vertex_buffer);
+    gl->BufferData (GL_ARRAY_BUFFER, 4 * 5 * sizeof (GLfloat), vertices,
+        GL_STATIC_DRAW);
+  }
+
+  if (!gl_sink->vbo_indices) {
+    gl->GenBuffers (1, &gl_sink->vbo_indices);
+    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, gl_sink->vbo_indices);
+    gl->BufferData (GL_ELEMENT_ARRAY_BUFFER, sizeof (indices), indices,
+        GL_STATIC_DRAW);
+  }
 
   if (gl->GenVertexArrays) {
+    _bind_buffer (gl_sink);
     gl->BindVertexArray (0);
-    gl->BindBuffer (GL_ARRAY_BUFFER, 0);
-  } else {
-    _unbind_buffer (gl_sink);
   }
+
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
+  gl->BindBuffer (GL_ARRAY_BUFFER, 0);
 }
 
 static void
@@ -1425,6 +1439,11 @@ gst_glimage_sink_cleanup_glthread (GstGLImageSink * gl_sink)
     gl->DeleteVertexArrays (1, &gl_sink->vao);
     gl_sink->vao = 0;
   }
+
+  if (gl_sink->vbo_indices) {
+    gl->DeleteVertexArrays (1, &gl_sink->vbo_indices);
+    gl_sink->vbo_indices = 0;
+  }
 }
 
 static void
@@ -1537,7 +1556,6 @@ gst_glimage_sink_on_draw (GstGLImageSink * gl_sink)
 
   if (!do_redisplay) {
     gfloat alpha = gl_sink->ignore_alpha ? 1.0f : 0.0f;
-    GLushort indices[] = { 0, 1, 2, 0, 2, 3 };
 
     gl->ClearColor (0.0, 0.0, 0.0, alpha);
     gl->Clear (GL_COLOR_BUFFER_BIT);
@@ -1560,7 +1578,7 @@ gst_glimage_sink_on_draw (GstGLImageSink * gl_sink)
     gl->BindTexture (GL_TEXTURE_2D, gl_sink->redisplay_texture);
     gst_gl_shader_set_uniform_1i (gl_sink->redisplay_shader, "tex", 0);
 
-    gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices);
+    gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0);
 
     gst_gl_context_clear_shader (gl_sink->context);
 
diff --git a/ext/gl/gstglimagesink.h b/ext/gl/gstglimagesink.h
index ce93ba7..f11442c 100644
--- a/ext/gl/gstglimagesink.h
+++ b/ext/gl/gstglimagesink.h
@@ -89,6 +89,7 @@ struct _GstGLImageSink
 
     GstGLShader *redisplay_shader;
     GLuint vao;
+    GLuint vbo_indices;
     GLuint vertex_buffer;
     GLint  attr_position;
     GLint  attr_texture;
diff --git a/ext/gl/gstgloverlay.c b/ext/gl/gstgloverlay.c
index 916389b..8c8638d 100644
--- a/ext/gl/gstgloverlay.c
+++ b/ext/gl/gstgloverlay.c
@@ -158,6 +158,11 @@ gst_gl_overlay_reset_gl_resources (GstGLFilter * filter)
     overlay->vbo = 0;
   }
 
+  if (overlay->vbo_indices) {
+    gl->DeleteBuffers (1, &overlay->vbo_indices);
+    overlay->vbo_indices = 0;
+  }
+
   if (overlay->overlay_vao) {
     gl->DeleteVertexArrays (1, &overlay->overlay_vao);
     overlay->overlay_vao = 0;
@@ -369,6 +374,7 @@ _unbind_buffer (GstGLOverlay * overlay)
 {
   const GstGLFuncs *gl = GST_GL_BASE_FILTER (overlay)->context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
   gl->BindBuffer (GL_ARRAY_BUFFER, 0);
 
   gl->DisableVertexAttribArray (overlay->attr_position);
@@ -380,6 +386,7 @@ _bind_buffer (GstGLOverlay * overlay, GLuint vbo)
 {
   const GstGLFuncs *gl = GST_GL_BASE_FILTER (overlay)->context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, overlay->vbo_indices);
   gl->BindBuffer (GL_ARRAY_BUFFER, vbo);
 
   gl->EnableVertexAttribArray (overlay->attr_position);
@@ -399,6 +406,8 @@ float v_vertices[] = {
    1.0f,  1.0f, 0.0f, 1.0f, 1.0f,
   -1.0f,  1.0f, 0.0f, 0.0f, 1.0f,
 };
+
+static const GLushort indices[] = { 0, 1, 2, 0, 2, 3, };
 /* *INDENT-ON* */
 
 static void
@@ -411,11 +420,6 @@ gst_gl_overlay_callback (gint width, gint height, guint texture, gpointer stuff)
   gboolean memory_mapped = FALSE;
   const GstGLFuncs *gl = GST_GL_BASE_FILTER (filter)->context->gl_vtable;
 
-  GLushort indices[] = {
-    0, 1, 2,
-    0, 2, 3,
-  };
-
 #if GST_GL_HAVE_OPENGL
   if (gst_gl_context_get_gl_api (GST_GL_BASE_FILTER (filter)->context) &
       GST_GL_API_OPENGL) {
@@ -453,8 +457,18 @@ gst_gl_overlay_callback (gint width, gint height, guint texture, gpointer stuff)
     gl->BufferData (GL_ARRAY_BUFFER, 4 * 5 * sizeof (GLfloat), v_vertices,
         GL_STATIC_DRAW);
 
-    if (gl->GenVertexArrays)
+    gl->GenBuffers (1, &overlay->vbo_indices);
+    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, overlay->vbo_indices);
+    gl->BufferData (GL_ELEMENT_ARRAY_BUFFER, sizeof (indices), indices,
+        GL_STATIC_DRAW);
+
+    if (gl->GenVertexArrays) {
       _bind_buffer (overlay, overlay->vbo);
+      gl->BindVertexArray (0);
+    }
+
+    gl->BindBuffer (GL_ARRAY_BUFFER, 0);
+    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
   }
 
   if (gl->GenVertexArrays)
@@ -462,7 +476,7 @@ gst_gl_overlay_callback (gint width, gint height, guint texture, gpointer stuff)
   else
     _bind_buffer (overlay, overlay->vbo);
 
-  gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices);
+  gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0);
 
   if (!overlay->image_memory)
     goto out;
@@ -482,9 +496,14 @@ gst_gl_overlay_callback (gint width, gint height, guint texture, gpointer stuff)
 
     gl->GenBuffers (1, &overlay->overlay_vbo);
     gl->BindBuffer (GL_ARRAY_BUFFER, overlay->overlay_vbo);
+    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, overlay->vbo_indices);
     overlay->geometry_change = TRUE;
   }
 
+  if (gl->GenVertexArrays) {
+    gl->BindVertexArray (overlay->overlay_vao);
+  }
+
   if (overlay->geometry_change) {
     gint render_width, render_height;
     gfloat x, y, image_width, image_height;
@@ -524,19 +543,20 @@ gst_gl_overlay_callback (gint width, gint height, guint texture, gpointer stuff)
         GL_STATIC_DRAW);
   }
 
-  if (gl->GenVertexArrays) {
-    if (overlay->geometry_change)
-      _bind_buffer (overlay, overlay->overlay_vbo);
-    gl->BindVertexArray (overlay->overlay_vao);
-    gl->BindBuffer (GL_ARRAY_BUFFER, 0);
-  } else {
+  if (!gl->GenVertexArrays || overlay->geometry_change) {
     _bind_buffer (overlay, overlay->overlay_vbo);
   }
 
   gl->BindTexture (GL_TEXTURE_2D, image_tex);
   gst_gl_shader_set_uniform_1f (overlay->shader, "alpha", overlay->alpha);
 
-  gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices);
+  gl->Enable (GL_BLEND);
+  gl->BlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+  gl->BlendEquation (GL_FUNC_ADD);
+
+  gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0);
+
+  gl->Disable (GL_BLEND);
 
 out:
   if (gl->GenVertexArrays) {
diff --git a/ext/gl/gstgloverlay.h b/ext/gl/gstgloverlay.h
index d81a0a0..c9e08b0 100644
--- a/ext/gl/gstgloverlay.h
+++ b/ext/gl/gstgloverlay.h
@@ -67,6 +67,7 @@ struct _GstGLOverlay
   GLuint        overlay_vao;
   GLuint        vbo;
   GLuint        overlay_vbo;
+  GLuint        vbo_indices;
   GLuint        attr_position;
   GLuint        attr_texture;
 };
diff --git a/ext/gl/gstgltransformation.c b/ext/gl/gstgltransformation.c
index 4bd022e..bf2f9ab 100644
--- a/ext/gl/gstgltransformation.c
+++ b/ext/gl/gstgltransformation.c
@@ -407,6 +407,11 @@ gst_gl_transformation_reset_gl (GstGLFilter * filter)
     transformation->vertex_buffer = 0;
   }
 
+  if (transformation->vbo_indices) {
+    gl->DeleteBuffers (1, &transformation->vbo_indices);
+    transformation->vbo_indices = 0;
+  }
+
   if (transformation->shader) {
     gst_object_unref (transformation->shader);
     transformation->shader = NULL;
@@ -464,6 +469,7 @@ gst_gl_transformation_filter_texture (GstGLFilter * filter, guint in_tex,
   return TRUE;
 }
 
+static const GLushort indices[] = { 0, 1, 2, 3, 0 };
 
 static void
 _upload_vertices (GstGLTransformation * transformation)
@@ -492,6 +498,7 @@ _bind_buffer (GstGLTransformation * transformation)
   const GstGLFuncs *gl =
       GST_GL_BASE_FILTER (transformation)->context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, transformation->vbo_indices);
   gl->BindBuffer (GL_ARRAY_BUFFER, transformation->vertex_buffer);
 
   /* Load the vertex position */
@@ -512,6 +519,7 @@ _unbind_buffer (GstGLTransformation * transformation)
   const GstGLFuncs *gl =
       GST_GL_BASE_FILTER (transformation)->context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
   gl->BindBuffer (GL_ARRAY_BUFFER, 0);
 
   gl->DisableVertexAttribArray (transformation->attr_position);
@@ -525,8 +533,6 @@ gst_gl_transformation_callback (gpointer stuff)
   GstGLTransformation *transformation = GST_GL_TRANSFORMATION (filter);
   GstGLFuncs *gl = GST_GL_BASE_FILTER (filter)->context->gl_vtable;
 
-  GLushort indices[] = { 0, 1, 2, 3, 0 };
-
   GLfloat temp_matrix[16];
 
   gst_gl_context_clear_shader (GST_GL_BASE_FILTER (filter)->context);
@@ -559,6 +565,12 @@ gst_gl_transformation_callback (gpointer stuff)
     }
 
     gl->GenBuffers (1, &transformation->vertex_buffer);
+
+    gl->GenBuffers (1, &transformation->vbo_indices);
+    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, transformation->vbo_indices);
+    gl->BufferData (GL_ELEMENT_ARRAY_BUFFER, sizeof (indices), indices,
+        GL_STATIC_DRAW);
+
     transformation->caps_change = TRUE;
   }
 
@@ -569,8 +581,11 @@ gst_gl_transformation_callback (gpointer stuff)
     _upload_vertices (transformation);
     _bind_buffer (transformation);
 
-    if (gl->GenVertexArrays)
+    if (gl->GenVertexArrays) {
+      gl->BindVertexArray (0);
+      gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
       gl->BindBuffer (GL_ARRAY_BUFFER, 0);
+    }
   } else if (!gl->GenVertexArrays) {
     _bind_buffer (transformation);
   }
diff --git a/ext/gl/gstgltransformation.h b/ext/gl/gstgltransformation.h
index 5b02014..b5eaeb6 100644
--- a/ext/gl/gstgltransformation.h
+++ b/ext/gl/gstgltransformation.h
@@ -42,6 +42,7 @@ struct _GstGLTransformation
 
     GstGLShader *shader;
     GLuint       vao;
+    GLuint       vbo_indices;
     GLuint       vertex_buffer;
     GLint        attr_position;
     GLint        attr_texture;
diff --git a/ext/gl/gstglvideomixer.c b/ext/gl/gstglvideomixer.c
index f7a3eb1..f393137 100644
--- a/ext/gl/gstglvideomixer.c
+++ b/ext/gl/gstglvideomixer.c
@@ -733,6 +733,11 @@ _reset_gl (GstGLContext * context, GstGLVideoMixer * video_mixer)
     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);
 }
@@ -790,6 +795,21 @@ gst_gl_video_mixer_process_textures (GstGLMixer * mix, GPtrArray * frames,
   return TRUE;
 }
 
+static const GLushort indices[] = { 0, 1, 2, 0, 2, 3 };
+
+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
 _draw_checker_background (GstGLVideoMixer * video_mixer)
 {
@@ -797,10 +817,6 @@ _draw_checker_background (GstGLVideoMixer * video_mixer)
   const GstGLFuncs *gl = GST_GL_BASE_MIXER (mixer)->context->gl_vtable;
   gint attr_position_loc = 0;
 
-  const GLushort indices[] = {
-    0, 1, 2,
-    0, 2, 3
-  };
   /* *INDENT-OFF* */
   gfloat v_vertices[] = {
     -1.0,-1.0,-1.0f,
@@ -820,12 +836,15 @@ _draw_checker_background (GstGLVideoMixer * video_mixer)
   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);
   }
 
@@ -834,9 +853,10 @@ _draw_checker_background (GstGLVideoMixer * video_mixer)
 
   gl->EnableVertexAttribArray (attr_position_loc);
 
-  gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices);
+  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;
@@ -884,11 +904,6 @@ gst_gl_video_mixer_callback (gpointer stuff)
   GLint attr_texture_loc = 0;
   guint out_width, out_height;
 
-  const GLushort indices[] = {
-    0, 1, 2,
-    0, 2, 3
-  };
-
   guint count = 0;
 
   out_width = GST_VIDEO_INFO_WIDTH (&vagg->info);
@@ -958,6 +973,8 @@ gst_gl_video_mixer_callback (gpointer stuff)
 
     in_tex = frame->texture;
 
+    _init_vbo_indices (video_mixer);
+
     if (pad->geometry_change || !pad->vertex_buffer) {
       gint pad_width, pad_height;
       gfloat w, h;
@@ -993,6 +1010,7 @@ gst_gl_video_mixer_callback (gpointer stuff)
     } 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);
@@ -1011,7 +1029,7 @@ gst_gl_video_mixer_callback (gpointer stuff)
     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, indices);
+    gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0);
 
     ++count;
   }
@@ -1022,6 +1040,7 @@ gst_gl_video_mixer_callback (gpointer stuff)
   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);
 
diff --git a/ext/gl/gstglvideomixer.h b/ext/gl/gstglvideomixer.h
index 967358b..0d0252b 100644
--- a/ext/gl/gstglvideomixer.h
+++ b/ext/gl/gstglvideomixer.h
@@ -64,6 +64,7 @@ struct _GstGLVideoMixer
     GPtrArray *input_frames;
 
     GLuint vao;
+    GLuint vbo_indices;
     GLuint checker_vbo;
 };
 
diff --git a/gst-libs/gst/gl/gstglcolorconvert.c b/gst-libs/gst/gl/gstglcolorconvert.c
index 4f56da7..081fc76 100644
--- a/gst-libs/gst/gl/gstglcolorconvert.c
+++ b/gst-libs/gst/gl/gstglcolorconvert.c
@@ -1219,6 +1219,7 @@ _bind_buffer (GstGLColorConvert * convert)
 {
   const GstGLFuncs *gl = convert->context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, convert->priv->vbo_indices);
   gl->BindBuffer (GL_ARRAY_BUFFER, convert->priv->vertex_buffer);
 
   /* Load the vertex position */
@@ -1238,6 +1239,7 @@ _unbind_buffer (GstGLColorConvert * convert)
 {
   const GstGLFuncs *gl = convert->context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
   gl->BindBuffer (GL_ARRAY_BUFFER, 0);
 
   gl->DisableVertexAttribArray (convert->priv->attr_position);
@@ -1378,23 +1380,20 @@ _init_convert (GstGLColorConvert * convert)
     gl->BufferData (GL_ARRAY_BUFFER, 4 * 5 * sizeof (GLfloat), vertices,
         GL_STATIC_DRAW);
 
+    gl->GenBuffers (1, &convert->priv->vbo_indices);
+    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, convert->priv->vbo_indices);
+    gl->BufferData (GL_ELEMENT_ARRAY_BUFFER, sizeof (indices), indices,
+        GL_STATIC_DRAW);
+
     if (gl->GenVertexArrays) {
       _bind_buffer (convert);
       gl->BindVertexArray (0);
     }
 
     gl->BindBuffer (GL_ARRAY_BUFFER, 0);
+    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
   }
 
-  if (!convert->priv->vbo_indices) {
-    gl->GenBuffers (1, &convert->priv->vbo_indices);
-    gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, convert->priv->vbo_indices);
-    gl->BufferData (GL_ELEMENT_ARRAY_BUFFER, sizeof (indices), indices,
-        GL_STATIC_DRAW);
-    gl->BindBuffer (GL_ARRAY_BUFFER, 0);
-  }
-
-
   gl->BindTexture (GL_TEXTURE_2D, 0);
 
   convert->initted = TRUE;
@@ -1737,7 +1736,6 @@ _do_convert_draw (GstGLContext * context, GstGLColorConvert * convert)
     g_free (scale_name);
   }
 
-  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, convert->priv->vbo_indices);
   gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0);
 
   if (gl->BindVertexArray)
@@ -1748,8 +1746,6 @@ _do_convert_draw (GstGLContext * context, GstGLColorConvert * convert)
   if (gl->DrawBuffer)
     gl->DrawBuffer (GL_NONE);
 
-  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
-
   /* we are done with the shader */
   gst_gl_context_clear_shader (context);
 
diff --git a/gst-libs/gst/gl/gstglfilter.c b/gst-libs/gst/gl/gstglfilter.c
index 169ded9..5dced6d 100644
--- a/gst-libs/gst/gl/gstglfilter.c
+++ b/gst-libs/gst/gl/gstglfilter.c
@@ -239,6 +239,11 @@ gst_gl_filter_gl_stop (GstGLBaseFilter * base_filter)
     filter->vertex_buffer = 0;
   }
 
+  if (filter->vbo_indices) {
+    gl->DeleteBuffers (1, &filter->vbo_indices);
+    filter->vbo_indices = 0;
+  }
+
   if (filter->fbo != 0) {
     gst_gl_context_del_fbo (context, filter->fbo, filter->depthbuffer);
   }
@@ -1057,6 +1062,8 @@ static const GLfloat vertices[] = {
    1.0f,  1.0f, 0.0f, 1.0f, 1.0f,
   -1.0f,  1.0f, 0.0f, 0.0f, 1.0f
 };
+
+static const GLushort indices[] = { 0, 1, 2, 0, 2, 3 };
 /* *INDENT-ON* */
 
 static void
@@ -1065,6 +1072,7 @@ _bind_buffer (GstGLFilter * filter)
   GstGLContext *context = GST_GL_BASE_FILTER (filter)->context;
   const GstGLFuncs *gl = context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, filter->vbo_indices);
   gl->BindBuffer (GL_ARRAY_BUFFER, filter->vertex_buffer);
 
   _get_attributes (filter);
@@ -1087,6 +1095,7 @@ _unbind_buffer (GstGLFilter * filter)
   GstGLContext *context = GST_GL_BASE_FILTER (filter)->context;
   const GstGLFuncs *gl = context->gl_vtable;
 
+  gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
   gl->BindBuffer (GL_ARRAY_BUFFER, 0);
 
   gl->DisableVertexAttribArray (filter->draw_attr_position_loc);
@@ -1145,8 +1154,6 @@ gst_gl_filter_draw_texture (GstGLFilter * filter, GLuint texture,
 #endif
   if (gst_gl_context_get_gl_api (context) & (GST_GL_API_GLES2 |
           GST_GL_API_OPENGL3)) {
-    GLushort indices[] = { 0, 1, 2, 0, 2, 3 };
-
     if (!filter->vertex_buffer) {
       if (gl->GenVertexArrays) {
         gl->GenVertexArrays (1, &filter->vao);
@@ -1158,10 +1165,18 @@ gst_gl_filter_draw_texture (GstGLFilter * filter, GLuint texture,
       gl->BufferData (GL_ARRAY_BUFFER, 4 * 5 * sizeof (GLfloat), vertices,
           GL_STATIC_DRAW);
 
+      gl->GenBuffers (1, &filter->vbo_indices);
+      gl->BindBuffer (GL_ARRAY_BUFFER, filter->vbo_indices);
+      gl->BufferData (GL_ARRAY_BUFFER, sizeof (indices), indices,
+          GL_STATIC_DRAW);
+
       if (gl->GenVertexArrays) {
         _bind_buffer (filter);
-        gl->BindBuffer (GL_ARRAY_BUFFER, 0);
+        gl->BindVertexArray (0);
       }
+
+      gl->BindBuffer (GL_ARRAY_BUFFER, 0);
+      gl->BindBuffer (GL_ELEMENT_ARRAY_BUFFER, 0);
     }
 
     if (gl->GenVertexArrays)
@@ -1169,7 +1184,7 @@ gst_gl_filter_draw_texture (GstGLFilter * filter, GLuint texture,
     else
       _bind_buffer (filter);
 
-    gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, indices);
+    gl->DrawElements (GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, 0);
 
     if (gl->GenVertexArrays)
       gl->BindVertexArray (0);
diff --git a/gst-libs/gst/gl/gstglfilter.h b/gst-libs/gst/gl/gstglfilter.h
index a5caf32..98f4bd5 100644
--- a/gst-libs/gst/gl/gstglfilter.h
+++ b/gst-libs/gst/gl/gstglfilter.h
@@ -75,6 +75,7 @@ struct _GstGLFilter
   GstGLShader       *default_shader;
 
   GLuint             vao;
+  GLuint             vbo_indices;
   GLuint             vertex_buffer;
   GLint              draw_attr_position_loc;
   GLint              draw_attr_texture_loc;
-- 
2.7.4