[gtk/ngl-clip-classification] Collect clip stats

[Matthias Clasen <matthiasc src gnome org>]

commit 03187cf4795d9d09d945bad7921f21d307c9fd04
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Mar 8 09:47:36 2021 -0500

    Collect clip stats

 gsk/ngl/gsknglrenderer.c  |  4 ++++
 gsk/ngl/gsknglrenderjob.c | 28 ++++++++++++++++++++++++++++
 2 files changed, 32 insertions(+)
---
diff --git a/gsk/ngl/gsknglrenderer.c b/gsk/ngl/gsknglrenderer.c
index 66edc98d5d..41b0662a9c 100644
--- a/gsk/ngl/gsknglrenderer.c
+++ b/gsk/ngl/gsknglrenderer.c
@@ -286,6 +286,8 @@ gsk_ngl_renderer_dispose (GObject *object)
   G_OBJECT_CLASS (gsk_ngl_renderer_parent_class)->dispose (object);
 }
 
+extern void dump_clip_stats (void);
+
 static void
 gsk_ngl_renderer_class_init (GskNglRendererClass *klass)
 {
@@ -298,6 +300,8 @@ gsk_ngl_renderer_class_init (GskNglRendererClass *klass)
   renderer_class->unrealize = gsk_ngl_renderer_unrealize;
   renderer_class->render = gsk_ngl_renderer_render;
   renderer_class->render_texture = gsk_ngl_renderer_render_texture;
+
+  g_atexit (dump_clip_stats);
 }
 
 static void
diff --git a/gsk/ngl/gsknglrenderjob.c b/gsk/ngl/gsknglrenderjob.c
index aa038028c8..bd2aff0eb7 100644
--- a/gsk/ngl/gsknglrenderjob.c
+++ b/gsk/ngl/gsknglrenderjob.c
@@ -1030,10 +1030,38 @@ gsk_ngl_render_job_draw_offscreen_rect (GskNglRenderJob       *job,
   gsk_ngl_render_job_draw_coords (job, min_x, min_y, max_x, max_y);
 }
 
+static guint64 clips[3];
+static guint64 total;
+
+static void
+clip_stats (GskNglRenderJob *job)
+{
+  total++;
+  if (job->current_clip->is_fully_contained)
+    clips[0]++;
+  else if (job->current_clip->is_rectilinear)
+    clips[1]++;
+  else
+    clips[2]++;
+}
+
+void dump_clip_stats (void);
+
+void
+dump_clip_stats (void)
+{
+  g_print ("%f%% no clip\n%f%%rect clip\n%f%% full clip\n",
+           clips[0]*100.0 / (double)total,
+           clips[1]*100.0 / (double)total,
+           clips[2]*100.0 / (double)total);
+}
+
 static inline void
 gsk_ngl_render_job_begin_draw (GskNglRenderJob *job,
                                GskNglProgram   *program)
 {
+  clip_stats (job);
+
   job->current_program = program;
 
   gsk_ngl_command_queue_begin_draw (job->command_queue,