Removed SDL2_gfx dependency

Since the upgrade to SDL2 it was only used for framerate limiting, which
I've replicated in a small helper class.

Also reduced the framerate limit while minimized from 100 to 10 FPS.

3 files changed, 48 insertions, 24 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index a138578b..465ba0e8 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -1,5 +1,5 @@
 include(FindPkgConfig)
-pkg_check_modules(SDL2 REQUIRED sdl2>=2.0.1 SDL2_image SDL2_mixer SDL2_net SDL2_ttf SDL2_gfx)
+pkg_check_modules(SDL2 REQUIRED sdl2>=2.0.1 SDL2_image SDL2_mixer SDL2_net SDL2_ttf)
 FIND_PACKAGE(PhysFS REQUIRED)
 FIND_PACKAGE(CURL REQUIRED)
 FIND_PACKAGE(LibXml2 REQUIRED)
diff --git a/src/client.cpp b/src/client.cpp
index df360d17..18d95ac8 100644
--- a/src/client.cpp
+++ b/src/client.cpp
@@ -29,12 +29,8 @@
 #include "game.h"
 #include "itemshortcut.h"
 #include "keyboardconfig.h"
-#ifdef USE_OPENGL
-#include "openglgraphics.h"
-#endif
 #include "playerrelations.h"
 #include "sound.h"
-#include "units.h"
 
 #include "gui/changeemaildialog.h"
 #include "gui/changepassworddialog.h"
@@ -86,8 +82,6 @@
 #ifdef _WIN32
 #include <SDL_syswm.h>
 #include "utils/specialfolder.h"
-#else
-#include <cerrno>
 #endif
 
 #include <sys/stat.h>
@@ -152,9 +146,8 @@ int get_elapsed_time(int startTime)
 {
     if (startTime <= tick_time)
         return (tick_time - startTime) * MILLISECONDS_IN_A_TICK;
-    else
-        return (tick_time + (MAX_TICK_VALUE - startTime))
-                * MILLISECONDS_IN_A_TICK;
+
+    return (tick_time + (MAX_TICK_VALUE - startTime)) * MILLISECONDS_IN_A_TICK;
 }
 
 bool isDoubleClick(int selected)
@@ -174,6 +167,36 @@ bool isDoubleClick(int selected)
     return false;
 }
 
+/**
+ * A simple but effective frame rate limiter.
+ * Based on FPSmanager in SDL2_gfx.
+ */
+void FpsManager::limitFps(int fpsLimit)
+{
+    if (fpsLimit <= 0)
+        return;
+
+    const auto ticks = SDL_GetTicks();
+
+    // Need to reset if the FPS limit changes
+    if (mBaseTicks > 0 && mFpsLimit == fpsLimit)
+    {
+        ++mFrameCount;
+        const auto targetTicks = mBaseTicks + mFrameCount * 1000 / mFpsLimit;
+
+        // Make sure ticks hasn't wrapped
+        if (ticks > mBaseTicks && targetTicks > ticks)
+        {
+            SDL_Delay(targetTicks - ticks);
+            return;
+        }
+    }
+
+    mFpsLimit = fpsLimit;
+    mFrameCount = 0;
+    mBaseTicks = ticks;
+}
+
 
 Client *Client::mInstance = nullptr;
 
@@ -411,9 +434,6 @@ Client::Client(const Options &options):
     mLogicCounterId = SDL_AddTimer(MILLISECONDS_IN_A_TICK, nextTick, nullptr);
     mSecondsCounterId = SDL_AddTimer(1000, nextSecond, nullptr);
 
-    // Initialize frame limiting
-    SDL_initFramerate(&mFpsManager);
-
     listen(Event::ConfigChannel);
 
     //TODO: fix having to fake a option changed event
@@ -524,15 +544,13 @@ int Client::exec()
             frame_count++;
             gui->draw();
             graphics->updateScreen();
+            mFpsManager.limitFps(mFpsLimit);
         }
         else
         {
-            SDL_Delay(10);
+            mFpsManager.limitFps(10);
         }
 
-        if (mLimitFps)
-            SDL_framerateDelay(&mFpsManager);
-
         // TODO: Add connect timeouts
         if (mState == STATE_CONNECT_GAME &&
                  Net::getGameHandler()->isConnected())
@@ -1012,10 +1030,7 @@ void Client::event(Event::Channel channel, const Event &event)
         event.getType() == Event::ConfigOptionChanged &&
         event.getString("option") == "fpslimit")
     {
-        const int fpsLimit = config.getIntValue("fpslimit");
-        mLimitFps = fpsLimit > 0;
-        if (mLimitFps)
-            SDL_setFramerate(&mFpsManager, fpsLimit);
+        mFpsLimit = config.getIntValue("fpslimit");
     }
 }
 
diff --git a/src/client.h b/src/client.h
index 5b88dd5a..be591979 100644
--- a/src/client.h
+++ b/src/client.h
@@ -30,7 +30,6 @@
 #include <guichan/actionlistener.hpp>
 
 #include <SDL.h>
-#include <SDL2_framerate.h>
 
 #include <string>
 
@@ -117,6 +116,16 @@ enum State {
     STATE_FORCE_QUIT
 };
 
+class FpsManager
+{
+    int mFpsLimit = 0;
+    uint32_t mFrameCount = 0;
+    uint32_t mBaseTicks = 0;
+
+public:
+    void limitFps(int fpsLimit);
+};
+
 /**
  * The core part of the client. This class initializes all subsystems, runs
  * the event loop, and shuts everything down again.
@@ -249,8 +258,8 @@ private:
     SDL_TimerID mLogicCounterId = 0;
     SDL_TimerID mSecondsCounterId = 0;
 
-    bool mLimitFps = false;
-    FPSmanager mFpsManager;
+    int mFpsLimit = 0;
+    FpsManager mFpsManager;
 };
 
 #endif // CLIENT_H