cogl/framebuffer: Move discard_buffers() to driver sub types

It was implemented slightly different depending on whether it was for a
surface or FBO, so move it to their corresponding GL driver types.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1514>

cogl/cogl/cogl-driver.h

@@ -85,10 +85,6 @@ struct _CoglDriverVtable
                                CoglFramebuffer      *read_buffer,
                                CoglFramebufferState  state);
 
-  void
-  (* framebuffer_discard_buffers) (CoglFramebuffer *framebuffer,
-                                   unsigned long buffers);
-
   void
   (* framebuffer_draw_attributes) (CoglFramebuffer *framebuffer,
                                    CoglPipeline *pipeline,

cogl/cogl/cogl-framebuffer-driver.c

@@ -93,6 +93,13 @@ cogl_framebuffer_driver_flush (CoglFramebufferDriver *driver)
   COGL_FRAMEBUFFER_DRIVER_GET_CLASS (driver)->flush (driver);
 }
 
+void
+cogl_framebuffer_driver_discard_buffers (CoglFramebufferDriver *driver,
+                                         unsigned long          buffers)
+{
+  COGL_FRAMEBUFFER_DRIVER_GET_CLASS (driver)->discard_buffers (driver, buffers);
+}
+
 static void
 cogl_framebuffer_driver_get_property (GObject    *object,
                                       guint       prop_id,

cogl/cogl/cogl-framebuffer-driver.h

@@ -55,6 +55,9 @@ struct _CoglFramebufferDriverClass
   void (* finish) (CoglFramebufferDriver *driver);
 
   void (* flush) (CoglFramebufferDriver *driver);
+
+  void (* discard_buffers) (CoglFramebufferDriver *driver,
+                            unsigned long          buffers);
 };
 
 CoglFramebuffer *
@@ -78,4 +81,8 @@ cogl_framebuffer_driver_finish (CoglFramebufferDriver *driver);
 void
 cogl_framebuffer_driver_flush (CoglFramebufferDriver *driver);
 
+void
+cogl_framebuffer_driver_discard_buffers (CoglFramebufferDriver *driver,
+                                         unsigned long          buffers);
+
 #endif /* COGL_FRAMEBUFFER_DRIVER_H */

cogl/cogl/cogl-framebuffer.c

@@ -1695,11 +1695,10 @@ cogl_framebuffer_discard_buffers (CoglFramebuffer *framebuffer,
 {
   CoglFramebufferPrivate *priv =
     cogl_framebuffer_get_instance_private (framebuffer);
-  CoglContext *ctx = priv->context;
 
   g_return_if_fail (buffers & COGL_BUFFER_BIT_COLOR);
 
-  ctx->driver_vtable->framebuffer_discard_buffers (framebuffer, buffers);
+  cogl_framebuffer_driver_discard_buffers (priv->driver, buffers);
 }
 
 void

cogl/cogl/driver/gl/cogl-framebuffer-gl-private.h

@@ -51,10 +51,6 @@ struct _CoglGlFramebufferClass
                  GLenum             target);
 };
 
-void
-_cogl_framebuffer_gl_discard_buffers (CoglFramebuffer *framebuffer,
-                                      unsigned long buffers);
-
 void
 cogl_gl_framebuffer_bind (CoglGlFramebuffer *gl_framebuffer,
                           GLenum             target);

cogl/cogl/driver/gl/cogl-framebuffer-gl.c

@@ -328,44 +328,6 @@ cogl_gl_framebuffer_flush (CoglFramebufferDriver *driver)
   GE (ctx, glFlush ());
 }
 
-void
-_cogl_framebuffer_gl_discard_buffers (CoglFramebuffer *framebuffer,
-                                      unsigned long buffers)
-{
-  CoglContext *ctx = cogl_framebuffer_get_context (framebuffer);
-
-  if (ctx->glDiscardFramebuffer)
-    {
-      GLenum attachments[3];
-      int i = 0;
-
-      if (COGL_IS_ONSCREEN (framebuffer))
-        {
-          if (buffers & COGL_BUFFER_BIT_COLOR)
-            attachments[i++] = GL_COLOR;
-          if (buffers & COGL_BUFFER_BIT_DEPTH)
-            attachments[i++] = GL_DEPTH;
-          if (buffers & COGL_BUFFER_BIT_STENCIL)
-            attachments[i++] = GL_STENCIL;
-        }
-      else
-        {
-          if (buffers & COGL_BUFFER_BIT_COLOR)
-            attachments[i++] = GL_COLOR_ATTACHMENT0;
-          if (buffers & COGL_BUFFER_BIT_DEPTH)
-            attachments[i++] = GL_DEPTH_ATTACHMENT;
-          if (buffers & COGL_BUFFER_BIT_STENCIL)
-            attachments[i++] = GL_STENCIL_ATTACHMENT;
-        }
-
-      cogl_context_flush_framebuffer_state (ctx,
-                                            framebuffer,
-                                            framebuffer,
-                                            COGL_FRAMEBUFFER_STATE_BIND);
-      GE (ctx, glDiscardFramebuffer (GL_FRAMEBUFFER, i, attachments));
-    }
-}
-
 void
 _cogl_framebuffer_gl_draw_attributes (CoglFramebuffer *framebuffer,
                                       CoglPipeline *pipeline,

cogl/cogl/driver/gl/cogl-gl-framebuffer-back.c

@@ -155,6 +155,33 @@ cogl_gl_framebuffer_back_query_bits (CoglFramebufferDriver *driver,
   *bits = gl_framebuffer_back->bits;
 }
 
+static void
+cogl_gl_framebuffer_back_discard_buffers (CoglFramebufferDriver *driver,
+                                          unsigned long          buffers)
+{
+  CoglFramebuffer *framebuffer =
+    cogl_framebuffer_driver_get_framebuffer (driver);
+  CoglContext *ctx = cogl_framebuffer_get_context (framebuffer);
+  GLenum attachments[3];
+  int i = 0;
+
+  if (!ctx->glDiscardFramebuffer)
+    return;
+
+  if (buffers & COGL_BUFFER_BIT_COLOR)
+    attachments[i++] = GL_COLOR;
+  if (buffers & COGL_BUFFER_BIT_DEPTH)
+    attachments[i++] = GL_DEPTH;
+  if (buffers & COGL_BUFFER_BIT_STENCIL)
+    attachments[i++] = GL_STENCIL;
+
+  cogl_context_flush_framebuffer_state (ctx,
+                                        framebuffer,
+                                        framebuffer,
+                                        COGL_FRAMEBUFFER_STATE_BIND);
+  GE (ctx, glDiscardFramebuffer (GL_FRAMEBUFFER, i, attachments));
+}
+
 static void
 cogl_gl_framebuffer_back_bind (CoglGlFramebuffer *gl_framebuffer,
                                GLenum             target)
@@ -232,6 +259,7 @@ cogl_gl_framebuffer_back_class_init (CoglGlFramebufferBackClass *klass)
     COGL_GL_FRAMEBUFFER_CLASS (klass);
 
   driver_class->query_bits = cogl_gl_framebuffer_back_query_bits;
+  driver_class->discard_buffers = cogl_gl_framebuffer_back_discard_buffers;
 
   gl_framebuffer_class->bind = cogl_gl_framebuffer_back_bind;
 }

cogl/cogl/driver/gl/cogl-gl-framebuffer-fbo.c

@@ -173,6 +173,33 @@ cogl_gl_framebuffer_fbo_query_bits (CoglFramebufferDriver *driver,
   *bits = gl_framebuffer_fbo->bits;
 }
 
+static void
+cogl_gl_framebuffer_fbo_discard_buffers (CoglFramebufferDriver *driver,
+                                         unsigned long          buffers)
+{
+  CoglFramebuffer *framebuffer =
+    cogl_framebuffer_driver_get_framebuffer (driver);
+  CoglContext *ctx = cogl_framebuffer_get_context (framebuffer);
+  GLenum attachments[3];
+  int i = 0;
+
+  if (!ctx->glDiscardFramebuffer)
+    return;
+
+  if (buffers & COGL_BUFFER_BIT_COLOR)
+    attachments[i++] = GL_COLOR_ATTACHMENT0;
+  if (buffers & COGL_BUFFER_BIT_DEPTH)
+    attachments[i++] = GL_DEPTH_ATTACHMENT;
+  if (buffers & COGL_BUFFER_BIT_STENCIL)
+    attachments[i++] = GL_STENCIL_ATTACHMENT;
+
+  cogl_context_flush_framebuffer_state (ctx,
+                                        framebuffer,
+                                        framebuffer,
+                                        COGL_FRAMEBUFFER_STATE_BIND);
+  GE (ctx, glDiscardFramebuffer (GL_FRAMEBUFFER, i, attachments));
+}
+
 static void
 cogl_gl_framebuffer_fbo_bind (CoglGlFramebuffer *gl_framebuffer,
                               GLenum             target)
@@ -606,6 +633,7 @@ cogl_gl_framebuffer_fbo_class_init (CoglGlFramebufferFboClass *klass)
   object_class->dispose = cogl_gl_framebuffer_fbo_dispose;
 
   driver_class->query_bits = cogl_gl_framebuffer_fbo_query_bits;
+  driver_class->discard_buffers = cogl_gl_framebuffer_fbo_discard_buffers;
 
   gl_framebuffer_class->bind = cogl_gl_framebuffer_fbo_bind;
 }

cogl/cogl/driver/gl/gl/cogl-driver-gl.c

@@ -571,7 +571,6 @@ _cogl_driver_gl =
     _cogl_driver_update_features,
     _cogl_driver_gl_create_framebuffer_driver,
     _cogl_driver_gl_flush_framebuffer_state,
-    _cogl_framebuffer_gl_discard_buffers,
     _cogl_framebuffer_gl_draw_attributes,
     _cogl_framebuffer_gl_draw_indexed_attributes,
     _cogl_framebuffer_gl_read_pixels_into_bitmap,

cogl/cogl/driver/gl/gles/cogl-driver-gles.c

@@ -459,7 +459,6 @@ _cogl_driver_gles =
     _cogl_driver_update_features,
     _cogl_driver_gl_create_framebuffer_driver,
     _cogl_driver_gl_flush_framebuffer_state,
-    _cogl_framebuffer_gl_discard_buffers,
     _cogl_framebuffer_gl_draw_attributes,
     _cogl_framebuffer_gl_draw_indexed_attributes,
     _cogl_framebuffer_gl_read_pixels_into_bitmap,

cogl/cogl/driver/nop/cogl-driver-nop.c

@@ -99,7 +99,6 @@ _cogl_driver_nop =
     _cogl_driver_update_features,
     _cogl_driver_nop_create_framebuffer_driver,
     _cogl_driver_nop_flush_framebuffer_state,
-    _cogl_framebuffer_nop_discard_buffers,
     _cogl_framebuffer_nop_draw_attributes,
     _cogl_framebuffer_nop_draw_indexed_attributes,
     _cogl_framebuffer_nop_read_pixels_into_bitmap,

cogl/cogl/driver/nop/cogl-framebuffer-nop-private.h

@@ -37,10 +37,6 @@
 #include "cogl-types.h"
 #include "cogl-context-private.h"
 
-void
-_cogl_framebuffer_nop_discard_buffers (CoglFramebuffer *framebuffer,
-                                       unsigned long buffers);
-
 void
 _cogl_framebuffer_nop_draw_attributes (CoglFramebuffer *framebuffer,
                                        CoglPipeline *pipeline,

cogl/cogl/driver/nop/cogl-framebuffer-nop.c

@@ -35,12 +35,6 @@
 #include <glib.h>
 #include <string.h>
 
-void
-_cogl_framebuffer_nop_discard_buffers (CoglFramebuffer *framebuffer,
-                                       unsigned long buffers)
-{
-}
-
 void
 _cogl_framebuffer_nop_draw_attributes (CoglFramebuffer *framebuffer,
                                        CoglPipeline *pipeline,

cogl/cogl/driver/nop/cogl-nop-framebuffer.c

@@ -64,6 +64,12 @@ cogl_nop_framebuffer_flush (CoglFramebufferDriver *driver)
 {
 }
 
+static void
+cogl_nop_framebuffer_discard_buffers (CoglFramebufferDriver *driver,
+                                      unsigned long          buffers)
+{
+}
+
 static void
 cogl_nop_framebuffer_init (CoglNopFramebuffer *nop_framebuffer)
 {
@@ -79,4 +85,5 @@ cogl_nop_framebuffer_class_init (CoglNopFramebufferClass *klass)
   driver_class->clear = cogl_nop_framebuffer_clear;
   driver_class->finish = cogl_nop_framebuffer_finish;
   driver_class->flush = cogl_nop_framebuffer_flush;
+  driver_class->discard_buffers = cogl_nop_framebuffer_discard_buffers;
 }