Fix GitHub Issue #43: Add option to force screen on multi-display setups

- There's now --screen CLI option that works when in fullscreen mode.

  E.g. --screen 1

README.md

@@ -98,6 +98,10 @@ where you can place your own race tracks.
 
 E.g. `dustrac-game --lang it`
 
+`--screen [index]` forces the screen on multi-display setups when in fullscreen mode. 
+
+E.g. `dustrac-game --screen 1` would start the game on the second display.
+
 ## Building the project
 
 Please refer to the `INSTALL` document for build/install instructions if you're

src/game/game.cpp

@@ -59,6 +59,7 @@ Game::Game(int & argc, char ** argv)
 , m_renderer(nullptr)
 , m_scene(nullptr)
 , m_trackLoader(new TrackLoader)
+, m_screenIndex(m_settings.loadValue(m_settings.screenKey(), 0))
 , m_updateFps(60)
 , m_updateDelay(1000 / m_updateFps)
 , m_timeStep(1000 / m_updateFps)
@@ -128,9 +129,10 @@ static void printHelp()
     std::cout << std::endl << "Dust Racing 2D version " << VERSION << std::endl;
     std::cout << Config::Common::COPYRIGHT << std::endl << std::endl;
     std::cout << "Options:" << std::endl;
-    std::cout << "--help        Show this help." << std::endl;
-    std::cout << "--lang [lang] Force language: fi, fr, it, cs." << std::endl;
-    std::cout << "--no-vsync    Force vsync off." << std::endl;
+    std::cout << "--help            Show this help." << std::endl;
+    std::cout << "--screen [index]  Force a certain screen on multi-display setups." << std::endl;
+    std::cout << "--lang [lang]     Force language: fi, fr, it, cs." << std::endl;
+    std::cout << "--no-vsync        Force vsync off." << std::endl;
     std::cout << std::endl;
 }
 
@@ -164,6 +166,11 @@ void Game::parseArgs(int argc, char ** argv)
             printHelp();
             throw UserException("Exit due to help.");
         }
+        else if (args[i] == "--screen" && (i + i) < args.size())
+        {
+            m_screenIndex = args[i + 1].toInt();
+            m_settings.saveValue(m_settings.screenKey(), m_screenIndex);
+        }
         else if (args[i] == "--lang" && (i + i) < args.size())
         {
             lang = args[i + 1];
@@ -179,25 +186,6 @@ void Game::parseArgs(int argc, char ** argv)
 
 void Game::createRenderer()
 {
-    // Create the main window / renderer
-    int hRes, vRes;
-    bool fullScreen = false;
-
-    m_settings.loadResolution(hRes, vRes, fullScreen);
-
-    if (!hRes || !vRes)
-    {
-        hRes = QGuiApplication::primaryScreen()->geometry().width();
-        vRes = QGuiApplication::primaryScreen()->geometry().height();
-    }
-
-    adjustSceneSize(hRes, vRes);
-
-    MCLogger().info()
-        << "Resolution: " << hRes << " " << vRes << " " << fullScreen;
-
-    MCLogger().info() << "Creating the renderer..";
-
     QSurfaceFormat format;
 
 #ifdef __MC_GL30__
@@ -222,12 +210,39 @@ void Game::createRenderer()
     }
 #endif
 
+    // Create the main window / renderer
+    int hRes, vRes;
+    bool fullScreen = false;
+
+    m_settings.loadResolution(hRes, vRes, fullScreen);
+
+    const auto screens = QGuiApplication::screens();
+
+    MCLogger().info() << "Screen: " << m_screenIndex << "/" << screens.size();
+
+    m_screen = m_screenIndex < screens.size() ? screens.at(m_screenIndex) : screens.at(0);
+
+    if (!hRes || !vRes)
+    {
+        hRes = m_screen->geometry().width();
+        vRes = m_screen->geometry().height();
+    }
+
+    adjustSceneSize(m_screen->geometry().width(), m_screen->geometry().height());
+
+    MCLogger().info() << "Screen resolution: " << m_screen->geometry().width() << " " << m_screen->geometry().height();
+
+    MCLogger().info() << "Virtual resolution: " << hRes << " " << vRes << " " << fullScreen;
+
+    MCLogger().info() << "Creating the renderer..";
+
     m_renderer = new Renderer(hRes, vRes, fullScreen, m_world->renderer().glScene());
     m_renderer->setFormat(format);
     m_renderer->setCursor(Qt::BlankCursor);
 
     if (fullScreen)
     {
+        m_renderer->setGeometry(m_screen->geometry());
         m_renderer->showFullScreen();
     }
     else
@@ -324,6 +339,11 @@ int Game::run()
     return m_app.exec();
 }
 
+QScreen * Game::screen() const
+{
+  return m_screen;
+}
+
 bool Game::loadTracks()
 {
     // Load track data

src/game/game.hpp

@@ -36,6 +36,7 @@ class StartlightsOverlay;
 class StateMachine;
 class TimingOverlay;
 class TrackLoader;
+class QScreen;
 
 //! The main game class.
 class Game : public QObject
@@ -114,6 +115,8 @@ class Game : public QObject
 
     const std::string & fontName() const;
 
+    QScreen * screen() const;
+
 public slots:
 
     void exitGame();
@@ -162,6 +165,10 @@ private slots:
 
     TrackLoader * m_trackLoader;
 
+    QScreen * m_screen = nullptr;
+
+    int m_screenIndex = 0;
+
     int m_updateFps;
 
     int m_updateDelay;

src/game/menu/resolutionmenu.cpp

@@ -27,8 +27,6 @@
 
 #include <MCLogger>
 
-#include <QApplication>
-#include <QDesktopWidget>
 #include <QObject> // for tr()
 #include <QScreen>
 
@@ -150,8 +148,8 @@ ResolutionMenu::ResolutionMenu(
 , m_confirmationMenu(confirmationMenu)
 {
     const int numResolutions = 8;
-    const int fullHRes = QGuiApplication::primaryScreen()->geometry().width();
-    const int fullVRes = QGuiApplication::primaryScreen()->geometry().height();
+    const int fullHRes = Game::instance().screen()->geometry().width();
+    const int fullVRes = Game::instance().screen()->geometry().height();
     const int itemHeight = height / (numResolutions + 3);
 
     int itemHRes = fullHRes;

src/game/renderer.cpp

@@ -38,8 +38,6 @@
 #include <cmath>
 #include <cassert>
 
-#include <QApplication>
-#include <QDesktopWidget>
 #include <QDir>
 #include <QFontDatabase>
 #include <QIcon>
@@ -60,8 +58,8 @@ Renderer::Renderer(int hRes, int vRes, bool fullScreen, MCGLScene & glScene)
 , m_enabled(false)
 , m_hRes(hRes)
 , m_vRes(vRes)
-, m_fullHRes(QGuiApplication::primaryScreen()->geometry().width())
-, m_fullVRes(QGuiApplication::primaryScreen()->geometry().height())
+, m_fullHRes(Game::instance().screen()->geometry().width())
+, m_fullVRes(Game::instance().screen()->geometry().height())
 , m_frameCounter(0)
 , m_fullScreen(fullScreen)
 , m_updatePending(false)

src/game/settings.cpp

@@ -57,6 +57,11 @@ QString Settings::soundsKey()
     return "sounds";
 }
 
+QString Settings::screenKey()
+{
+    return "screen";
+}
+
 QString Settings::vsyncKey()
 {
     return "vsync";

src/game/settings.hpp

@@ -66,9 +66,15 @@ class Settings
     int loadValue(QString key, int defaultValue = 0);
 
     static QString difficultyKey();
+
     static QString fpsKey();
+
     static QString lapCountKey();
+
     static QString soundsKey();
+
+    static QString screenKey();
+
     static QString vsyncKey();
 
 private: