From ca3e9e3b3b84fe95affbe5485212c6ecfa1a4b51 Mon Sep 17 00:00:00 2001

From: Olivier Fourdan <ofourdan@redhat.com>

Date: Tue, 22 Oct 2019 17:05:46 +0200

Subject: [PATCH 12/12] renderer-native: Separate offscreen and shadowfb

Create the intermediate shadow framebuffer for use exclusively when a

shadowfb is required.

Keep the previous offscreen framebuffer is as an intermediate

framebuffer for transformations only.

This way, we can apply transformations between in-memory framebuffers

prior to blit the result to screen, and achieve acceptable performance

even with software rendering on discrete GPU.

https://gitlab.gnome.org/GNOME/mutter/merge_requests/917

(cherry picked from commit 551641c74822ca2e3c685e49603836ebf5397df2)

---

 src/backends/native/meta-renderer-native.c | 29 ++++++++++++++++++----

 1 file changed, 24 insertions(+), 5 deletions(-)

diff --git a/src/backends/native/meta-renderer-native.c b/src/backends/native/meta-renderer-native.c

index 3cd01bcb7..ffb64a6bd 100644

--- a/src/backends/native/meta-renderer-native.c

+++ b/src/backends/native/meta-renderer-native.c

@@ -3287,7 +3287,6 @@ meta_renderer_native_create_onscreen (MetaRendererNative   *renderer_native,

 static CoglOffscreen *

 meta_renderer_native_create_offscreen (MetaRendererNative    *renderer,

                                        CoglContext           *context,

-                                       MetaMonitorTransform   transform,

                                        gint                   view_width,

                                        gint                   view_height,

                                        GError               **error)

@@ -3489,6 +3488,7 @@ meta_renderer_native_create_view (MetaRenderer       *renderer,

   MetaMonitorTransform view_transform;

   CoglOnscreen *onscreen = NULL;

   CoglOffscreen *offscreen = NULL;

+  CoglOffscreen *shadowfb = NULL;

   float scale;

   int width, height;

   MetaRendererView *view;

@@ -3515,18 +3515,35 @@ meta_renderer_native_create_view (MetaRenderer       *renderer,

   if (!onscreen)

     g_error ("Failed to allocate onscreen framebuffer: %s", error->message);

-  if (view_transform != META_MONITOR_TRANSFORM_NORMAL ||

-      should_force_shadow_fb (renderer_native,

-                              renderer_native->primary_gpu_kms))

+ if (view_transform != META_MONITOR_TRANSFORM_NORMAL)

     {

       offscreen = meta_renderer_native_create_offscreen (renderer_native,

                                                          cogl_context,

-                                                         view_transform,

                                                          width,

                                                          height,

                                                          &error);

       if (!offscreen)

         g_error ("Failed to allocate back buffer texture: %s", error->message);

+

+    }

+

+  if (should_force_shadow_fb (renderer_native,

+                              renderer_native->primary_gpu_kms))

+    {

+      int shadow_width;

+      int shadow_height;

+

+      /* The shadowfb must be the same size as the on-screen framebuffer */

+      shadow_width = cogl_framebuffer_get_width (COGL_FRAMEBUFFER (onscreen));

+      shadow_height = cogl_framebuffer_get_height (COGL_FRAMEBUFFER (onscreen));

+

+      shadowfb = meta_renderer_native_create_offscreen (renderer_native,

+                                                        cogl_context,

+                                                        shadow_width,

+                                                        shadow_height,

+                                                        &error);

+      if (!shadowfb)

+        g_error ("Failed to allocate shadow buffer texture: %s", error->message);

     }

   view = g_object_new (META_TYPE_RENDERER_VIEW,

@@ -3534,10 +3551,12 @@ meta_renderer_native_create_view (MetaRenderer       *renderer,

                        "scale", scale,

                        "framebuffer", onscreen,

                        "offscreen", offscreen,

+                       "shadowfb", shadowfb,

                        "logical-monitor", logical_monitor,

                        "transform", view_transform,

                        NULL);

   g_clear_pointer (&offscreen, cogl_object_unref);

+  g_clear_pointer (&shadowfb, cogl_object_unref);

   meta_onscreen_native_set_view (onscreen, view);

-- 

2.21.0