[mutter] cogl/framebuffer/gl: Move OpenGL driver fields to private struct

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit 209b78afd8834bd5c9e91a778bfc31bef6f33d39
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Oct 12 23:29:11 2020 +0200

    cogl/framebuffer/gl: Move OpenGL driver fields to private struct
    
    It's driver specific, so it shouldn't be kept in the generic data
    structure.
    
    https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1496

 cogl/cogl/cogl-framebuffer-private.h      | 15 +++++--
 cogl/cogl/cogl-framebuffer.c              | 24 ++++++++++-
 cogl/cogl/driver/gl/cogl-framebuffer-gl.c | 67 ++++++++++++++++++++++---------
 3 files changed, 81 insertions(+), 25 deletions(-)
---
diff --git a/cogl/cogl/cogl-framebuffer-private.h b/cogl/cogl/cogl-framebuffer-private.h
index 49df3055ad..4250897a6a 100644
--- a/cogl/cogl/cogl-framebuffer-private.h
+++ b/cogl/cogl/cogl-framebuffer-private.h
@@ -173,16 +173,15 @@ struct _CoglFramebuffer
   int clear_clip_y1;
   gboolean clear_clip_dirty;
 
-  /* driver specific */
-  gboolean dirty_bitmasks;
-  CoglFramebufferBits bits;
-
   int samples_per_pixel;
 
   /* Whether the depth buffer was enabled for this framebuffer,
  * usually means it needs to be cleared before being reused next.
  */
   gboolean depth_buffer_clear_needed;
+
+  gpointer driver_private;
+  GDestroyNotify driver_private_destroy;
 };
 
 typedef enum
@@ -398,4 +397,12 @@ _cogl_framebuffer_read_pixels_into_bitmap (CoglFramebuffer *framebuffer,
 COGL_EXPORT int
 _cogl_framebuffer_get_stencil_bits (CoglFramebuffer *framebuffer);
 
+gpointer
+cogl_framebuffer_get_driver_private (CoglFramebuffer *framebuffer);
+
+void
+cogl_framebuffer_set_driver_private (CoglFramebuffer *framebuffer,
+                                     gpointer         driver_private,
+                                     GDestroyNotify   desrtoy_notify);
+
 #endif /* __COGL_FRAMEBUFFER_PRIVATE_H */
diff --git a/cogl/cogl/cogl-framebuffer.c b/cogl/cogl/cogl-framebuffer.c
index 8a984972bb..32b0240cdb 100644
--- a/cogl/cogl/cogl-framebuffer.c
+++ b/cogl/cogl/cogl-framebuffer.c
@@ -118,8 +118,6 @@ _cogl_framebuffer_init (CoglFramebuffer *framebuffer,
   framebuffer->modelview_stack = cogl_matrix_stack_new (ctx);
   framebuffer->projection_stack = cogl_matrix_stack_new (ctx);
 
-  framebuffer->dirty_bitmasks = TRUE;
-
   framebuffer->samples_per_pixel = 0;
 
   framebuffer->clip_stack = NULL;
@@ -192,6 +190,11 @@ _cogl_framebuffer_free (CoglFramebuffer *framebuffer)
     ctx->current_draw_buffer = NULL;
   if (ctx->current_read_buffer == framebuffer)
     ctx->current_read_buffer = NULL;
+
+  if (framebuffer->driver_private_destroy)
+    framebuffer->driver_private_destroy (framebuffer->driver_private);
+  framebuffer->driver_private_destroy = NULL;
+  framebuffer->driver_private = NULL;
 }
 
 const CoglWinsysVtable *
@@ -2280,3 +2283,20 @@ cogl_framebuffer_draw_textured_rectangles (CoglFramebuffer *framebuffer,
                                                    rects,
                                                    n_rectangles);
 }
+
+gpointer
+cogl_framebuffer_get_driver_private (CoglFramebuffer *framebuffer)
+{
+  return framebuffer->driver_private;
+}
+
+void
+cogl_framebuffer_set_driver_private (CoglFramebuffer *framebuffer,
+                                     gpointer         driver_private,
+                                     GDestroyNotify   destroy_notify)
+{
+  g_warn_if_fail (!framebuffer->driver_private);
+
+  framebuffer->driver_private = driver_private;
+  framebuffer->driver_private_destroy = destroy_notify;
+}
diff --git a/cogl/cogl/driver/gl/cogl-framebuffer-gl.c b/cogl/cogl/driver/gl/cogl-framebuffer-gl.c
index 520beaf17e..82a6af4cf9 100644
--- a/cogl/cogl/driver/gl/cogl-framebuffer-gl.c
+++ b/cogl/cogl/driver/gl/cogl-framebuffer-gl.c
@@ -126,6 +126,11 @@
 #define GL_STENCIL 0x1802
 #endif
 
+typedef struct _CoglFramebufferGl
+{
+  gboolean dirty_bitmasks;
+  CoglFramebufferBits bits;
+} CoglFramebufferGl;
 
 static void
 _cogl_framebuffer_gl_flush_viewport_state (CoglFramebuffer *framebuffer)
@@ -921,12 +926,33 @@ _cogl_framebuffer_gl_clear (CoglFramebuffer *framebuffer,
   GE (ctx, glClear (gl_buffers));
 }
 
+static CoglFramebufferGl *
+ensure_framebuffer_gl (CoglFramebuffer *framebuffer)
+{
+  CoglFramebufferGl *framebuffer_gl;
+
+  framebuffer_gl = cogl_framebuffer_get_driver_private (framebuffer);
+  if (!framebuffer_gl)
+    {
+      framebuffer_gl = g_new0 (CoglFramebufferGl, 1);
+      cogl_framebuffer_set_driver_private (framebuffer,
+                                           framebuffer_gl,
+                                           g_free);
+      framebuffer_gl->dirty_bitmasks = TRUE;
+    }
+
+  return framebuffer_gl;
+}
+
 static inline void
 _cogl_framebuffer_init_bits (CoglFramebuffer *framebuffer)
 {
   CoglContext *ctx = framebuffer->context;
+  CoglFramebufferGl *framebuffer_gl;
 
-  if (G_LIKELY (!framebuffer->dirty_bitmasks))
+  framebuffer_gl = ensure_framebuffer_gl (framebuffer);
+
+  if (!framebuffer_gl->dirty_bitmasks)
     return;
 
   cogl_framebuffer_allocate (framebuffer, NULL);
@@ -970,7 +996,7 @@ _cogl_framebuffer_init_bits (CoglFramebuffer *framebuffer)
       for (i = 0; i < G_N_ELEMENTS (params); i++)
         {
           int *value =
-            (int *) ((uint8_t *) &framebuffer->bits + params[i].offset);
+            (int *) ((uint8_t *) &framebuffer_gl->bits + params[i].offset);
           GE( ctx, glGetFramebufferAttachmentParameteriv (GL_FRAMEBUFFER,
                                                           params[i].attachment,
                                                           params[i].pname,
@@ -980,12 +1006,12 @@ _cogl_framebuffer_init_bits (CoglFramebuffer *framebuffer)
   else
 #endif /* HAVE_COGL_GL */
     {
-      GE( ctx, glGetIntegerv (GL_RED_BITS,   &framebuffer->bits.red)   );
-      GE( ctx, glGetIntegerv (GL_GREEN_BITS, &framebuffer->bits.green) );
-      GE( ctx, glGetIntegerv (GL_BLUE_BITS,  &framebuffer->bits.blue)  );
-      GE( ctx, glGetIntegerv (GL_ALPHA_BITS, &framebuffer->bits.alpha) );
-      GE( ctx, glGetIntegerv (GL_DEPTH_BITS, &framebuffer->bits.depth) );
-      GE( ctx, glGetIntegerv (GL_STENCIL_BITS, &framebuffer->bits.stencil) );
+      GE( ctx, glGetIntegerv (GL_RED_BITS,   &framebuffer_gl->bits.red)   );
+      GE( ctx, glGetIntegerv (GL_GREEN_BITS, &framebuffer_gl->bits.green) );
+      GE( ctx, glGetIntegerv (GL_BLUE_BITS,  &framebuffer_gl->bits.blue)  );
+      GE( ctx, glGetIntegerv (GL_ALPHA_BITS, &framebuffer_gl->bits.alpha) );
+      GE( ctx, glGetIntegerv (GL_DEPTH_BITS, &framebuffer_gl->bits.depth) );
+      GE( ctx, glGetIntegerv (GL_STENCIL_BITS, &framebuffer_gl->bits.stencil) );
     }
 
   /* If we don't have alpha textures then the alpha bits are actually
@@ -994,8 +1020,8 @@ _cogl_framebuffer_init_bits (CoglFramebuffer *framebuffer)
       framebuffer->type == COGL_FRAMEBUFFER_TYPE_OFFSCREEN &&
       framebuffer->internal_format == COGL_PIXEL_FORMAT_A_8)
     {
-      framebuffer->bits.alpha = framebuffer->bits.red;
-      framebuffer->bits.red = 0;
+      framebuffer_gl->bits.alpha = framebuffer_gl->bits.red;
+      framebuffer_gl->bits.red = 0;
     }
 
   COGL_NOTE (OFFSCREEN,
@@ -1004,25 +1030,28 @@ _cogl_framebuffer_init_bits (CoglFramebuffer *framebuffer)
              framebuffer->type == COGL_FRAMEBUFFER_TYPE_OFFSCREEN
                ? "offscreen"
                : "onscreen",
-             framebuffer->bits.red,
-             framebuffer->bits.blue,
-             framebuffer->bits.green,
-             framebuffer->bits.alpha,
-             framebuffer->bits.depth,
-             framebuffer->bits.stencil);
-
-  framebuffer->dirty_bitmasks = FALSE;
+             framebuffer_gl->bits.red,
+             framebuffer_gl->bits.blue,
+             framebuffer_gl->bits.green,
+             framebuffer_gl->bits.alpha,
+             framebuffer_gl->bits.depth,
+             framebuffer_gl->bits.stencil);
+
+  framebuffer_gl->dirty_bitmasks = FALSE;
 }
 
 void
 _cogl_framebuffer_gl_query_bits (CoglFramebuffer *framebuffer,
                                  CoglFramebufferBits *bits)
 {
+  CoglFramebufferGl *framebuffer_gl;
+
   _cogl_framebuffer_init_bits (framebuffer);
 
   /* TODO: cache these in some driver specific location not
    * directly as part of CoglFramebuffer. */
-  *bits = framebuffer->bits;
+  framebuffer_gl = ensure_framebuffer_gl (framebuffer);
+  *bits = framebuffer_gl->bits;
 }
 
 void