From 3a93d527188c0a865c3648fcd8b57ba7b804872f Mon Sep 17 00:00:00 2001
From: Benjamin Otte <otte@redhat.com>
Date: Fri, 26 Jan 2024 16:54:04 +0100
Subject: [PATCH] gpu: Add support for MacOS default framebuffer

This adds the same code as the GL renderer used to allow backends to
redirect rendering to a different framebuffer.

Related: #6363
---
 gsk/gpu/gskglimage.c        | 10 +++++++++-
 gsk/gpu/gskglimageprivate.h |  1 +
 gsk/gpu/gsknglrenderer.c    |  1 +
 3 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/gsk/gpu/gskglimage.c b/gsk/gpu/gskglimage.c
index 41d6a4a422..7e6266c809 100644
--- a/gsk/gpu/gskglimage.c
+++ b/gsk/gpu/gskglimage.c
@@ -43,7 +43,7 @@ gsk_gl_image_finalize (GObject *object)
 {
   GskGLImage *self = GSK_GL_IMAGE (object);
 
-  if (self->framebuffer_id)
+  if (self->texture_id && self->framebuffer_id)
     glDeleteFramebuffers (1, &self->framebuffer_id);
 
   if (self->owns_texture)
@@ -70,6 +70,7 @@ gsk_gl_image_init (GskGLImage *self)
 
 GskGpuImage *
 gsk_gl_image_new_backbuffer (GskGLDevice    *device,
+                             GdkGLContext   *context,
                              GdkMemoryFormat format,
                              gsize           width,
                              gsize           height)
@@ -95,6 +96,13 @@ gsk_gl_image_new_backbuffer (GskGLDevice    *device,
 
   /* texture_id == 0 means backbuffer */
 
+  /* Check for non-standard framebuffer binding as we might not be using
+   * the default framebuffer on systems like macOS where we've bound an
+   * IOSurface to a GL_TEXTURE_RECTANGLE. Otherwise, no scissor clip will
+   * be applied in the command queue causing overdrawing.
+   */
+  self->framebuffer_id = GDK_GL_CONTEXT_GET_CLASS (context)->get_default_framebuffer (context);
+
   return GSK_GPU_IMAGE (self);
 }
 
diff --git a/gsk/gpu/gskglimageprivate.h b/gsk/gpu/gskglimageprivate.h
index aa8d6ee9d7..9f7a959ece 100644
--- a/gsk/gpu/gskglimageprivate.h
+++ b/gsk/gpu/gskglimageprivate.h
@@ -11,6 +11,7 @@ G_BEGIN_DECLS
 G_DECLARE_FINAL_TYPE (GskGLImage, gsk_gl_image, GSK, GL_IMAGE, GskGpuImage)
 
 GskGpuImage *           gsk_gl_image_new_backbuffer                     (GskGLDevice            *device,
+                                                                         GdkGLContext           *context,
                                                                          GdkMemoryFormat         format,
                                                                          gsize                   width,
                                                                          gsize                   height);
diff --git a/gsk/gpu/gsknglrenderer.c b/gsk/gpu/gsknglrenderer.c
index da2733cf57..b203a68d61 100644
--- a/gsk/gpu/gsknglrenderer.c
+++ b/gsk/gpu/gsknglrenderer.c
@@ -99,6 +99,7 @@ gsk_ngl_renderer_get_backbuffer (GskGpuRenderer *renderer)
     {
       gsk_ngl_renderer_free_backbuffer (self);
       self->backbuffer = gsk_gl_image_new_backbuffer (GSK_GL_DEVICE (gsk_gpu_renderer_get_device (renderer)),
+                                                      GDK_GL_CONTEXT (context),
                                                       GDK_MEMORY_DEFAULT /* FIXME */,
                                                       ceil (gdk_surface_get_width (surface) * scale),
                                                       ceil (gdk_surface_get_height (surface) * scale));