add configure option --without-internalsdlgfx for not use emdedded sdl2gfx.

1 files changed, 189 insertions, 0 deletions

diff --git a/src/sdl2gfx/SDL2_framerate.c b/src/sdl2gfx/SDL2_framerate.c
new file mode 100644
index 000000000..b31b0feb2
--- /dev/null
+++ b/src/sdl2gfx/SDL2_framerate.c
@@ -0,0 +1,189 @@
+/*
+
+SDL_framerate.c: framerate manager
+
+Copyright (C) 2001-2012  Andreas Schiffler
+
+This software is provided 'as-is', without any express or implied
+warranty. In no event will the authors be held liable for any damages
+arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose,
+including commercial applications, and to alter it and redistribute it
+freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not
+claim that you wrote the original software. If you use this software
+in a product, an acknowledgment in the product documentation would be
+appreciated but is not required.
+
+2. Altered source versions must be plainly marked as such, and must not be
+misrepresented as being the original software.
+
+3. This notice may not be removed or altered from any source
+distribution.
+
+Andreas Schiffler -- aschiffler at ferzkopp dot net
+
+Changed for ManaPlus (C) 2013  ManaPlus developers
+*/
+
+#include "SDL2_framerate.h"
+
+/*!
+\brief Internal wrapper to SDL_GetTicks that ensures a non-zero return value.
+
+\return The tick count.
+*/
+uint32_t _getTicks()
+{
+    const uint32_t ticks = SDL_GetTicks();
+
+    /* 
+    * Since baseticks!=0 is used to track initialization
+    * we need to ensure that the tick count is always >0 
+    * since SDL_GetTicks may not have incremented yet and
+    * return 0 depending on the timing of the calls.
+    */
+    if (ticks == 0)
+        return 1;
+    else
+        return ticks;
+}
+
+/*!
+\brief Initialize the framerate manager.
+
+Initialize the framerate manager, set default framerate of 30Hz and
+reset delay interpolation.
+
+\param manager Pointer to the framerate manager.
+*/
+void SDL_initFramerate(FPSmanager *const manager)
+{
+    /*
+    * Store some sane values 
+    */
+    manager->framecount = 0;
+    manager->rate = FPS_DEFAULT;
+    manager->rateticks = (1000.0f / (float) FPS_DEFAULT);
+    manager->baseticks = _getTicks();
+    manager->lastticks = manager->baseticks;
+
+}
+
+/*!
+\brief Set the framerate in Hz 
+
+Sets a new framerate for the manager and reset delay interpolation.
+Rate values must be between FPS_LOWER_LIMIT and FPS_UPPER_LIMIT inclusive to be accepted.
+
+\param manager Pointer to the framerate manager.
+\param rate The new framerate in Hz (frames per second).
+
+\return 0 for sucess and -1 for error.
+*/
+int SDL_setFramerate(FPSmanager *const manager, const uint32_t rate)
+{
+    if (rate >= FPS_LOWER_LIMIT && rate <= FPS_UPPER_LIMIT)
+    {
+        manager->framecount = 0;
+        manager->rate = rate;
+        manager->rateticks = (1000.0f / (float) rate);
+        return 0;
+    }
+    else
+    {
+        return -1;
+    }
+}
+
+/*!
+\brief Return the current target framerate in Hz 
+
+Get the currently set framerate of the manager.
+
+\param manager Pointer to the framerate manager.
+
+\return Current framerate in Hz or -1 for error.
+*/
+int SDL_getFramerate(FPSmanager *const manager)
+{
+    if (!manager)
+        return -1;
+    else
+        return (int)manager->rate;
+}
+
+/*!
+\brief Return the current framecount.
+
+Get the current framecount from the framerate manager. 
+A frame is counted each time SDL_framerateDelay is called.
+
+\param manager Pointer to the framerate manager.
+
+\return Current frame count or -1 for error.
+*/
+int SDL_getFramecount(FPSmanager *const manager)
+{
+    if (!manager)
+        return -1;
+    else
+        return (int)manager->framecount;
+}
+
+/*!
+\brief Delay execution to maintain a constant framerate and calculate fps.
+
+Generate a delay to accomodate currently set framerate. Call once in the
+graphics/rendering loop. If the computer cannot keep up with the rate (i.e.
+drawing too slow), the delay is zero and the delay interpolation is reset.
+
+\param manager Pointer to the framerate manager.
+
+\return The time that passed since the last call to the function in ms. May return 0.
+*/
+uint32_t SDL_framerateDelay(FPSmanager *const manager)
+{
+    uint32_t the_delay;
+
+    /*
+    * No manager, no delay
+    */
+    if (!manager)
+        return 0;
+
+    /*
+    * Initialize uninitialized manager 
+    */
+    if (manager->baseticks == 0)
+        SDL_initFramerate(manager);
+
+    /*
+    * Next frame 
+    */
+    manager->framecount ++;
+
+    /*
+    * Get/calc ticks 
+    */
+    const uint32_t current_ticks = _getTicks();
+    const uint32_t time_passed = current_ticks - manager->lastticks;
+    manager->lastticks = current_ticks;
+    const uint32_t target_ticks = manager->baseticks + (uint32_t)(
+        (float)(manager->framecount) * manager->rateticks);
+
+    if (current_ticks <= target_ticks)
+    {
+        the_delay = target_ticks - current_ticks;
+        SDL_Delay(the_delay);
+    }
+    else
+    {
+        manager->framecount = 0;
+        manager->baseticks = _getTicks();
+    }
+
+    return time_passed;
+}