libgui: Added GUI-friendly app loop timer

Activates the OpenGL context before triggering a loop iteration.

doomsday/sdk/libcore/include/de/core/loop.h

@@ -85,7 +85,7 @@ class DENG2_PUBLIC Loop : public QObject
     static Loop &get();
 
 public slots:
-    void nextLoopIteration();
+    virtual void nextLoopIteration();
 
 private:
     DENG2_PRIVATE(d)

doomsday/sdk/libgui/include/de/GuiLoop

@@ -0,0 +1 @@
+#include "gui/guiloop.h"

doomsday/sdk/libgui/include/de/gui/guiapp.h

@@ -22,7 +22,7 @@
 #include "libgui.h"
 #include <QApplication>
 #include <de/App>
-#include <de/Loop>
+#include <de/GuiLoop>
 
 /**
  * Macro for conveniently accessing the de::GuiApp singleton instance.
@@ -66,7 +66,7 @@ class LIBGUI_PUBLIC GuiApp : public QApplication, public App,
     int execLoop();
     void stopLoop(int code);
 
-    Loop &loop();
+    GuiLoop &loop();
 
 protected:
     NativePath appDataPath() const;

doomsday/sdk/libgui/include/de/gui/guiloop.h

@@ -0,0 +1,49 @@
+/** @file guiloop.h  Continually triggered loop.
+ *
+ * @authors Copyright (c) 2016 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * LGPL: http://www.gnu.org/licenses/lgpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+ * General Public License for more details. You should have received a copy of
+ * the GNU Lesser General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small>
+ */
+
+#ifndef GUILOOP_H
+#define GUILOOP_H
+
+#include <de/Loop>
+
+namespace de {
+
+class CanvasWindow;
+
+/**
+ * Continually triggered loop that activates a window when triggering iterations.
+ */
+class GuiLoop : public Loop
+{
+public:
+    GuiLoop();
+
+    void setWindow(CanvasWindow *window);
+
+    static GuiLoop &get();
+
+protected slots:
+    void nextLoopIteration() override;
+
+private:
+    DENG2_PRIVATE(d)
+};
+
+} // namespace de
+
+#endif // GUILOOP_H

doomsday/sdk/libgui/src/canvaswindow.cpp

@@ -60,7 +60,8 @@ DENG2_PIMPL(CanvasWindow)
     {
         if (thisPublic == mainWindow)
         {
-            mainWindow = 0;
+            GuiLoop::get().setWindow(nullptr);
+            mainWindow = nullptr;
         }
     }
 
@@ -180,6 +181,7 @@ CanvasWindow &CanvasWindow::main()
 void CanvasWindow::setMain(CanvasWindow *window)
 {
     mainWindow = window;
+    GuiLoop::get().setWindow(window);
 }
 
 } // namespace de

doomsday/sdk/libgui/src/guiapp.cpp

@@ -35,7 +35,7 @@ namespace de {
 
 DENG2_PIMPL(GuiApp)
 {
-    Loop loop;
+    GuiLoop loop;
 
     Impl(Public *i) : Base(i)
     {
@@ -120,7 +120,7 @@ void GuiApp::stopLoop(int code)
     return QApplication::exit(code);
 }
 
-Loop &GuiApp::loop()
+GuiLoop &GuiApp::loop()
 {
     return d->loop;
 }

doomsday/sdk/libgui/src/guiloop.cpp

@@ -0,0 +1,58 @@
+/** @file guiloop.cpp
+ *
+ * @authors Copyright (c) 2016 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * LGPL: http://www.gnu.org/licenses/lgpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
+ * General Public License for more details. You should have received a copy of
+ * the GNU Lesser General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small>
+ */
+
+#include "de/GuiLoop"
+#include "de/CanvasWindow"
+
+namespace de {
+
+DENG2_PIMPL_NOREF(GuiLoop)
+{
+    CanvasWindow *window = nullptr;
+};
+
+GuiLoop::GuiLoop()
+    : d(new Impl)
+{}
+
+void GuiLoop::setWindow(CanvasWindow *window)
+{
+    d->window = window;
+}
+
+GuiLoop &GuiLoop::get() // static
+{
+    return static_cast<GuiLoop &>(Loop::get());
+}
+
+void GuiLoop::nextLoopIteration()
+{
+    if (d->window)
+    {
+        d->window->glActivate();
+    }
+
+    Loop::nextLoopIteration();
+
+    if (d->window)
+    {
+        d->window->glDone();
+    }
+}
+
+} // namespace de