From a251e34dbbcb652906f7fddd2a72cbb5992b58ae Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Tue, 28 Jul 2009 13:44:19 +0100
Subject: [PATCH] [gl] Move check for vertex buffer support to individual
 operations.

As we can fallback instead of using vertex buffers, do so rather than
preventing any use of GL acceleration.
---
 src/cairo-gl-glyphs.c  |  3 +++
 src/cairo-gl-surface.c | 17 +++++++++--------
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/cairo-gl-glyphs.c b/src/cairo-gl-glyphs.c
index 9dc1e9ab8..691108367 100644
--- a/src/cairo-gl-glyphs.c
+++ b/src/cairo-gl-glyphs.c
@@ -343,6 +343,9 @@ _cairo_gl_surface_show_glyphs (void			*abstract_dst,
     cairo_gl_composite_setup_t composite_setup;
     GLuint vbo = 0;
 
+    if (! GLEW_ARB_vertex_buffer_object)
+	return CAIRO_INT_STATUS_UNSUPPORTED;
+
     if (! _cairo_gl_operator_is_supported (op))
         return CAIRO_INT_STATUS_UNSUPPORTED;
 
diff --git a/src/cairo-gl-surface.c b/src/cairo-gl-surface.c
index 55575f871..72d387604 100644
--- a/src/cairo-gl-surface.c
+++ b/src/cairo-gl-surface.c
@@ -93,15 +93,12 @@ _cairo_gl_context_init (cairo_gl_context_t *ctx)
     if (glewInit () != GLEW_OK)
 	return _cairo_error (CAIRO_STATUS_INVALID_FORMAT); /* XXX */
 
-    if (! GLEW_ARB_vertex_buffer_object ||
-	! GLEW_EXT_framebuffer_object ||
+    if (! GLEW_EXT_framebuffer_object ||
 	! GLEW_ARB_texture_env_combine ||
 	! GLEW_ARB_texture_non_power_of_two)
     {
 	fprintf (stderr,
 		 "Required GL extensions not available:\n");
-	if (! GLEW_ARB_vertex_buffer_object)
-	    fprintf (stderr, "    GL_ARB_vertex_buffer_object\n");
 	if (! GLEW_EXT_framebuffer_object)
 	    fprintf (stderr, "    GL_EXT_framebuffer_object\n");
 	if (! GLEW_ARB_texture_env_combine)
@@ -1775,7 +1772,14 @@ _cairo_gl_surface_check_span_renderer (cairo_operator_t	  op,
 				       cairo_antialias_t	  antialias,
 				       const cairo_composite_rectangles_t *rects)
 {
-    return _cairo_gl_operator_is_supported (op);
+    if (! _cairo_gl_operator_is_supported (op))
+	return FALSE;
+
+    if (! GLEW_ARB_vertex_buffer_object)
+	return FALSE;
+
+    return TRUE;
+
     (void) pattern;
     (void) abstract_dst;
     (void) antialias;
@@ -1881,9 +1885,6 @@ _cairo_gl_surface_create_span_renderer (cairo_operator_t	 op,
     cairo_surface_attributes_t *src_attributes;
     GLenum err;
 
-    if (!GLEW_ARB_vertex_buffer_object)
-	return _cairo_span_renderer_create_in_error (CAIRO_INT_STATUS_UNSUPPORTED);
-
     renderer = calloc (1, sizeof (*renderer));
     if (unlikely (renderer == NULL))
 	return _cairo_span_renderer_create_in_error (CAIRO_STATUS_NO_MEMORY);