Refactor|Client|Server: Removed loop callbacks, added BusyWidget

Instead of loop callbacks from LegacyCore, the equivalent functionality
is now handled as part of the CanvasWindow's widget tree. In the case
of the server, which has no UI, loop iteration is run in ServerSystem.

At present time, the best way to model the client UI is to have two
root widgets, one for the normal UI and one for the busy UI.

Todo for later: Merge the busy mode visualization into BusyWidget.

doomsday/client/client.pro

@@ -340,6 +340,7 @@ DENG_HEADERS += \
     include/ui/b_main.h \
     include/ui/b_util.h \
     include/ui/busyvisual.h \
+    include/ui/busywidget.h \
     include/ui/canvas.h \
     include/ui/canvaswindow.h \
     include/ui/dd_input.h \
@@ -620,6 +621,7 @@ SOURCES += \
     src/ui/b_main.cpp \
     src/ui/b_util.cpp \
     src/ui/busyvisual.cpp \
+    src/ui/busywidget.cpp \
     src/ui/canvas.cpp \
     src/ui/canvaswindow.cpp \
     src/ui/dd_input.cpp \

doomsday/client/include/busymode.h

@@ -37,10 +37,6 @@
 
 #include "dd_share.h"
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 /// @return  @c true if specified thread is the current busy task worker.
 boolean BusyMode_IsWorkerThread(uint threadId);
 
@@ -50,8 +46,6 @@ boolean BusyMode_InWorkerThread(void);
 /// @return  Current busy task, else @c NULL.
 BusyTask* BusyMode_CurrentTask(void);
 
-#ifdef __cplusplus
-} // extern "C"
-#endif
+void BusyMode_Loop(void);
 
 #endif /// LIBDENG_CORE_BUSYMODE_H

doomsday/client/include/clientapp.h

@@ -38,6 +38,9 @@ class ClientApp : public de::GuiApp
      */
     void initialize();
 
+    void preFrame();
+    void postFrame();
+
 public:
     static ClientApp &app();
     static ServerLink &serverLink();

doomsday/client/include/dd_loop.h

@@ -42,11 +42,6 @@ void DD_RegisterLoop(void);
  */
 int DD_GameLoop(void);
 
-/**
- * Called periodically while the game loop is running.
- */
-void DD_GameLoopCallback(void);
-
 /**
  * Runs one or more tics depending on how much time has passed since the
  * previous call to this function. This gets called once per each main loop

doomsday/client/include/ui/busywidget.h

@@ -0,0 +1,41 @@
+/** @file busywidget.h
+ *
+ * @authors Copyright (c) 2013 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * GPL: http://www.gnu.org/licenses/gpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 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 General
+ * Public License for more details. You should have received a copy of the GNU
+ * General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small> 
+ */
+
+#ifndef CLIENT_BUSYWIDGET_H
+#define CLIENT_BUSYWIDGET_H
+
+#include "guiwidget.h"
+
+/**
+ * Widget that takes care of the UI while busy mode is active.
+ */
+class BusyWidget : public GuiWidget
+{
+public:
+    BusyWidget(de::String const &name = "");
+    ~BusyWidget();
+
+    void update();
+    void draw();
+    bool handleEvent(de::Event const &event);
+
+private:
+    DENG2_PRIVATE(d)
+};
+
+#endif // CLIENT_BUSYWIDGET_H

doomsday/client/include/ui/canvas.h

@@ -26,10 +26,13 @@
 #  error "canvas.h requires __CLIENT__"
 #endif
 
-struct image_s; // see image.h
+#include <de/Observers>
+#include <de/libdeng2.h>
 
 #include <QGLWidget>
-#include <de/libdeng2.h>
+
+struct image_s; // see image.h
+class CanvasWindow;
 
 #ifdef Q_WS_X11
 //#  define LIBDENG_CANVAS_TRACK_WITH_MOUSE_MOVE_EVENTS
@@ -52,7 +55,7 @@ class Canvas : public QGLWidget
     Q_OBJECT
 
 public:
-    explicit Canvas(QWidget *parent = 0, QGLWidget* shared = 0);
+    explicit Canvas(CanvasWindow *parent, QGLWidget* shared = 0);
     ~Canvas();
 
     /**
@@ -72,7 +75,7 @@ class Canvas : public QGLWidget
      *
      * @param canvasDrawFunc  Callback.
      */
-    void setDrawFunc(void (*canvasDrawFunc)(Canvas&));
+    //void setDrawFunc(void (*canvasDrawFunc)(Canvas&));
 
     /**
      * Sets the callback function that is called when the window's focus state changes.

doomsday/client/include/ui/canvaswindow.h

@@ -39,12 +39,29 @@ class CanvasWindow : public QMainWindow
 {
     Q_OBJECT
 
+public:
+    enum Mode
+    {
+        Normal,
+        Busy
+    };
+
 public:
     explicit CanvasWindow(QWidget *parent = 0);
     ~CanvasWindow();
 
     de::RootWidget &root();
 
+    /**
+     * Sets the operating mode of the window. In Busy mode, the normal
+     * widgets of the window will be replaced with a single BusyWidget.
+     *
+     * @param mode  Mode.
+     */
+    void setMode(Mode const &mode);
+
+    float frameRate() const;
+
     /**
      * Recreates the contained Canvas with an update GL format.
      * The context is shared with the old Canvas.
@@ -73,6 +90,21 @@ class CanvasWindow : public QMainWindow
     void resizeEvent(QResizeEvent *);
     void hideEvent(QHideEvent *);
 
+    /**
+     * Called from Canvas when it is ready for OpenGL drawing (visible).
+     *
+     * @param canvas  Canvas.
+     */
+    void canvasReady(Canvas &canvas);
+
+    /**
+     * Called from Canvas when a GL draw is requested. The UI widgets will be
+     * rendered onto the canvas.
+     *
+     * @param canvas  Canvas to paint.
+     */
+    void paintCanvas(Canvas &canvas);
+
     /**
      * Must be called before any canvas windows are created. Defines the
      * default OpenGL format settings for the contained canvases.

doomsday/client/include/ui/window.h

@@ -218,13 +218,15 @@ void Window_Show(Window* wnd, boolean show);
  */
 boolean Window_ChangeAttributes(Window* wnd, int* attribs);
 
+#if 0
 /**
  * Sets the function who will draw the contents of the window when needed.
  *
  * @param win       Window instance.
  * @param drawFunc  Callback function.
  */
 void Window_SetDrawFunc(Window* win, void (*drawFunc)(void));
+#endif
 
 /**
  * Request drawing the contents of the window as soon as possible.

doomsday/client/src/busymode.cpp

@@ -37,7 +37,8 @@
 
 #ifdef __CLIENT__
 
-static void BusyMode_Loop(void);
+#include "clientapp.h"
+
 static void BusyMode_Exit(void);
 
 static QEventLoop* eventLoop;
@@ -150,11 +151,6 @@ static void beginTask(BusyTask* task)
     busyThread = Sys_StartThread(busyTask->worker, busyTask->workerData);
     Thread_SetCallback(busyThread, busyWorkerTerminated);
 
-    // Switch the engine loop and window to the busy mode.
-    LegacyCore_SetLoopFunc(BusyMode_Loop);
-
-    Window_SetDrawFunc(Window_Main(), BusyVisual_Render);
-
     busyTask->_startTime = Timer_RealSeconds();
 }
 
@@ -171,9 +167,6 @@ static void endTask(BusyTask* task)
         Con_Message("Con_Busy: Was busy for %.2lf seconds.\n", busyTime);
     }
 
-    // The window drawer will be restored later to the appropriate function.
-    Window_SetDrawFunc(Window_Main(), 0);
-
     if(busyTaskEndedWithError)
     {
         Con_AbnormalShutdown(busyError);
@@ -245,17 +238,14 @@ static void preBusySetup(int initialMode)
 
     busyWasIgnoringInput = DD_IgnoreInput(true);
 
-    // Save the present loop.
-    LegacyCore_PushLoop();
-
-    // Set up loop for busy mode.
-    LegacyCore_SetLoopRate(60);
-    LegacyCore_SetLoopFunc(NULL); // don't call main loop's func while busy
-
     BusyVisual_PrepareFont();
     BusyVisual_LoadTextures();
 
-    Window_SetDrawFunc(Window_Main(), 0);
+    // Limit frame rate to 60, no point pushing it any faster while busy.
+    ClientApp::app().loop().setRate(60);
+
+    // Switch the window to busy mode UI.
+    Window_CanvasWindow(Window_Main())->setMode(CanvasWindow::Busy);
 
 #else
     DENG_UNUSED(initialMode);
@@ -271,11 +261,11 @@ static void postBusyCleanup(void)
 
     BusyVisual_ReleaseTextures();
 
-    // Restore old loop.
-    LegacyCore_PopLoop();
+    // Back to unlimited frame rate.
+    ClientApp::app().loop().setRate(0);
 
-    // Resume drawing with the game loop drawer.
-    Window_SetDrawFunc(Window_Main(), !Sys_IsShuttingDown()? DD_GameLoopDrawer : 0);
+    // Switch the window to normal UI.
+    Window_CanvasWindow(Window_Main())->setMode(CanvasWindow::Normal);
 #endif
 }
 
@@ -407,7 +397,7 @@ static void stopEventLoopWithValue(int result)
 {
     // After the event loop is gone, we don't want any loop callbacks until the
     // busy state has been properly torn down.
-    LegacyCore_SetLoopFunc(0);
+    //LegacyCore_SetLoopFunc(0);
 
     DENG_ASSERT(eventLoop != 0);
     eventLoop->exit(result);
@@ -438,16 +428,11 @@ static void BusyMode_Exit(void)
  * The busy loop callback function. Called periodically in the main (UI) thread
  * while the busy worker is running.
  */
-static void BusyMode_Loop(void)
+void BusyMode_Loop(void)
 {
     boolean canUpload = !(busyTask->mode & BUSYF_NO_UPLOADS);
     timespan_t oldTime;
 
-    Garbage_Recycle();
-
-    // Make sure the audio system gets regularly updated.
-    S_StartFrame();
-
     // Post and discard all input events.
     DD_ProcessEvents(0);
     DD_ProcessSharpEvents(0);
@@ -460,8 +445,6 @@ static void BusyMode_Loop(void)
         GL_ProcessDeferredTasks(15);
     }
 
-    S_EndFrame();
-
     // We accumulate time in the busy loop so that the animation of a task
     // sequence doesn't jump around but remains continuous.
     oldTime = busyTime;