Merge lp:~vanvugt/unity/fix-1043260-6.0 into lp:unity/6.0

[Daniel van Vugt]

Don't keep re-blurring parts of the shell we've already painted, because
that will creep in and look like a shadow on the edge of the blur region.
(LP: #1043260)

This happens when the same texture (the FBO texture) is both the source and
the destination for the three blur operations (launcher, panel, then dash).
My quick fix is to take a copy of the FBO texture at the start of the frame
(before any shell is painted), rather than reading from the same texture
(FBO) that we're writing to.

This also fixes LP: #1039999, because we are no longer assuming the backbuffer
is an FBO. Instead we let Nux decide and take the right steps to read the
real backbuffer, whatever that is.

See commit message.

[Daniel van Vugt (vanvugt)]

Warning:
This fix will slow down active blur a little.

If we desperately want to maintain performance then I suggest either:
  (a) Don't approve it and let the bugs slip into quantal b2; or
  (b) Ask a Nux/Unity expert to look at unity-shared/BackgroundEffectHelper.cpp and rewrite it to only do one blur (used by all geos) per frame.

[Sam Spilsbury (smspillaz)]

Hmm, is this correct?

16 + nux::ObjectPtr<nux::IOpenGLTexture2D> bg_texture =
17 + graphics_engine->CreateTextureFromBackBuffer(0, 0,
18 + screen->width(),
19 + screen->height());

I thought that nux will only read from the bound framebuffer object if nux actually knew about its existence. In this case, the compiz fbo is bound, but nux doesn't know about it, so it will read from the real backbuffer instead (which is not what you want).

I did just recently add a method to WindowCompositor to handle this case - see WindowCompositor::RestoreMainFramebuffer. You can probably use that in combination with SetReferenceFramebuffer, eg, RestoreMainFramebuffer -> SetReferenceFramebuffer -> CreateTextureFromBackbuffer.

A less roundabout way of doing that would be to have a GLFramebufferObject that unity *owns* and then we bind that and paint the compiz one into it. Then pass that one as the device texture. Once the blit framebuffer code is landed, we can use that on the unity side too.

[Daniel van Vugt (vanvugt)]

Sam,

I tried using your new Nux code to implement this and could not get it to make any difference. Care to prototype?

[Andrea Azzarone (azzar1)]

Works here.

review: Approve

[Unity Merger (unity-merger)]

Attempt to merge into lp:unity/6.0 failed due to conflicts:

text conflict in tests/autopilot/unity/tests/launcher/test_icon_behavior.py
text conflict in tests/gmockvolume.c

[Daniel van Vugt (vanvugt)]

The conflicts aren't real. That's just because lp:unity/6.0 got overwritten with the contents of lp:unity not long after this proposal. Now fixing...

[Daniel van Vugt (vanvugt)]

Damn. Now there are unwanted changes from other peoples' work :(

[Daniel van Vugt (vanvugt)]

review: Needs Fixing

[Andrea Azzarone (azzar1)]

review: Approve

=== modified file 'plugins/unityshell/src/unityshell.cpp'
--- plugins/unityshell/src/unityshell.cpp	2012-09-24 19:39:00 +0000
+++ plugins/unityshell/src/unityshell.cpp	2012-09-27 10:40:26 +0000
@@ -682,11 +682,15 @@
 
   auto gpu_device = nux::GetGraphicsDisplay()->GetGpuDevice();
 
-  nux::ObjectPtr<nux::IOpenGLTexture2D> device_texture =
-    gpu_device->CreateTexture2DFromID(gScreen->fbo ()->tex ()->name (),
-                                      screen->width(), screen->height(), 1, nux::BITFMT_R8G8B8A8);
-
-  gpu_device->backup_texture0_ = device_texture;
+  if (BackgroundEffectHelper::HasDirtyHelpers())
+  {
+    auto graphics_engine = nux::GetGraphicsDisplay()->GetGraphicsEngine();
+    nux::ObjectPtr<nux::IOpenGLTexture2D> bg_texture =
+      graphics_engine->CreateTextureFromBackBuffer(0, 0,
+                                                   screen->width(),
+                                                   screen->height());
+    gpu_device->backup_texture0_ = bg_texture;
+  }
 
   nux::Geometry geo(0, 0, screen->width (), screen->height ());
   nux::Geometry outputGeo(output->x (), output->y (), output->width (), output->height ());