windows: gl: Print GetLastError() when makeCurrent fails

This matches the behavior of other implementations, such as
QEGLPlatformContext: doing a qWarning with the relevant error
from eglGetError() or equivalent is helpful when something
goes wrong and should be common among QOpenGLPlatformContext
implementations.

Pick-to: 6.1
Task-number: QTBUG-85714
Change-Id: Ifa5d22b83808c92ae92efcbcddc8d8c3d3ba34b1
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>

1 files changed, 6 insertions, 1 deletions

diff --git a/src/plugins/platforms/windows/qwindowsglcontext.cpp b/src/plugins/platforms/windows/qwindowsglcontext.cpp
index 8c41cc135d..1a7be0d271 100644
--- a/src/plugins/platforms/windows/qwindowsglcontext.cpp
+++ b/src/plugins/platforms/windows/qwindowsglcontext.cpp
@@ -1301,7 +1301,10 @@ bool QWindowsGLContext::makeCurrent(QPlatformSurface *surface)
                 && QOpenGLStaticContext::opengl32.wglGetCurrentDC() == contextData->hdc) {
             return true;
         }
-        return QOpenGLStaticContext::opengl32.wglMakeCurrent(contextData->hdc, contextData->renderingContext);
+        const bool success = QOpenGLStaticContext::opengl32.wglMakeCurrent(contextData->hdc, contextData->renderingContext);
+        if (!success)
+            qErrnoWarning("%s: wglMakeCurrent() failed for existing context data", __FUNCTION__);
+        return success;
     }
     // Create a new entry.
     const QOpenGLContextData newContext(m_renderingContext, hwnd, GetDC(hwnd));
@@ -1329,6 +1332,8 @@ bool QWindowsGLContext::makeCurrent(QPlatformSurface *surface)
             qCDebug(lcQpaGl) << "makeCurrent(): context loss detected" << this;
             // Drop the surface. Will recreate on the next makeCurrent.
             window->invalidateSurface();
+        } else {
+            qErrnoWarning("%s: wglMakeCurrent() failed", __FUNCTION__);
         }
     }