[gtk: 1/2] gl renderer: Generate queries only on desktop GL

[Emmanuele Bassi <ebassi src gnome org>]

commit 08193ecf1cba16ddfec8229fdf3fdb99e16b4415
Author: Emmanuel Gil Peyrot <linkmauve linkmauve fr>
Date:   Sat Nov 7 20:14:07 2020 +0000

    gl renderer: Generate queries only on desktop GL
    
    On desktop GL, GL 1.5 or GL_ARB_occlusion_query is required to get the
    glGenQueries() etc. symbols.  This isn’t the case on GLES, where they
    are provided by GL_EXT_occlusion_query_boolean, and more importantly
    have never been made core.
    
    This patch allows gtk4-demo to start when GDK_DEBUG=gl-gles is set, on
    my Mali 400 MP running the Lima driver from Mesa.

 gsk/gl/gskglprofiler.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)
---
diff --git a/gsk/gl/gskglprofiler.c b/gsk/gl/gskglprofiler.c
index 0262bd20f8..9b834e5fc8 100644
--- a/gsk/gl/gskglprofiler.c
+++ b/gsk/gl/gskglprofiler.c
@@ -18,6 +18,7 @@ struct _GskGLProfiler
   GLuint gl_queries[N_QUERIES];
   GLuint active_query;
 
+  gboolean has_queries : 1;
   gboolean has_timer : 1;
   gboolean first_frame : 1;
 };
@@ -37,7 +38,8 @@ gsk_gl_profiler_finalize (GObject *gobject)
 {
   GskGLProfiler *self = GSK_GL_PROFILER (gobject);
 
-  glDeleteQueries (N_QUERIES, self->gl_queries);
+  if (self->has_queries)
+    glDeleteQueries (N_QUERIES, self->gl_queries);
 
   g_clear_object (&self->gl_context);
 
@@ -106,10 +108,14 @@ gsk_gl_profiler_class_init (GskGLProfilerClass *klass)
 static void
 gsk_gl_profiler_init (GskGLProfiler *self)
 {
-  glGenQueries (N_QUERIES, self->gl_queries);
+  self->has_queries = epoxy_is_desktop_gl();
+  self->has_timer = epoxy_is_desktop_gl() && (epoxy_gl_version () >= 33 || epoxy_has_gl_extension 
("GL_ARB_timer_query"));
+
+  if (!self->has_queries)
+    return;
 
+  glGenQueries (N_QUERIES, self->gl_queries);
   self->first_frame = TRUE;
-  self->has_timer = epoxy_gl_version () >= 33 || epoxy_has_gl_extension ("GL_ARB_timer_query");
 }
 
 GskGLProfiler *
@@ -127,7 +133,7 @@ gsk_gl_profiler_begin_gpu_region (GskGLProfiler *profiler)
 
   g_return_if_fail (GSK_IS_GL_PROFILER (profiler));
 
-  if (!profiler->has_timer)
+  if (!profiler->has_timer || !profiler->has_queries)
     return;
 
   query_id = profiler->gl_queries[profiler->active_query];
@@ -143,7 +149,7 @@ gsk_gl_profiler_end_gpu_region (GskGLProfiler *profiler)
 
   g_return_val_if_fail (GSK_IS_GL_PROFILER (profiler), 0);
 
-  if (!profiler->has_timer)
+  if (!profiler->has_timer || !profiler->has_queries)
     return 0;
 
   glEndQuery (GL_TIME_ELAPSED);