eglfs: Fix raster windows

Also sanitize the initial WebAssembly hack. Both eglfs and wasm lack the concept
of true raster windows. A QWindow with RasterSurface is rendered with OpenGL
no matter what. The two platforms took two different approaches to work around
the rest of the machinery:

- wasm disabled the QOpenGLContext warning for non-OpenGL QWindows,

- eglfs forced the QWindow surfaceType to OpenGLSurface whenever it was
  originally set to RasterSurface.

Now, the latter breaks since c4e9eabc309a275efc222f4127f31ba4677259b7, leaving
all raster window applications failing on eglfs, because flush in the backingstore
is now checking the surface type and disallows OpenGLSurface windows. (just like
how QOpenGLContext disallows RasterSurface windows)

To solve all this correctly, introduce a new platform capability,
OpenGLOnRasterSurface, and remove the special handling in the platform plugins.

Change-Id: I7785dfb1c955577bbdccdc14ebaaac5babdec57c
Fixes: QTBUG-77100
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/plugins/platforms/wasm/qwasmintegration.cpp b/src/plugins/platforms/wasm/qwasmintegration.cpp
index 3829043d07..05d6ae21f5 100644
--- a/src/plugins/platforms/wasm/qwasmintegration.cpp
+++ b/src/plugins/platforms/wasm/qwasmintegration.cpp
@@ -113,6 +113,7 @@ bool QWasmIntegration::hasCapability(QPlatformIntegration::Capability cap) const
     case RasterGLSurface: return false; // to enable this you need to fix qopenglwidget and quickwidget for wasm
     case MultipleWindows: return true;
     case WindowManagement: return true;
+    case OpenGLOnRasterSurface: return true;
     default: return QPlatformIntegration::hasCapability(cap);
     }
 }