在Windows下用MinGW+GCC编译SDL的注意事项
长期（大于3年）以来被一个极其郁闷的问题困扰：就是在自己用gcc编译的SDL.dll一直比libsdl.org官方发布的SDL.dll的性能弱。即使用同样的codebase也是如此，最初是怀疑编译器的版本不同造成的，今天仔细分析了SDL编译时的configure脚本的实现，才发现真正原因是SDL用来侦测DirectX的代码与我本地的MinGW的内置的include和libs不兼容造成的，使得SDL自动将DirectX加速给关掉了，只用最基本的GDI32+WaveOut来进行Video/Audio的渲染，而不是用DDraw+DSound来进行加速处理。
参照网址（http://www.libsdl.org/extras/win32/mingw32/README.txt）的介绍：
===========================================================================
Q: My version of SDL doesn't have DirectX support!
A: You need to get the DirectX development headers and libraries from:
http://www.libsdl.org/extras/win32/common/directx-devel.tar.gz
You need to unpack these in the /mingw directory.
做了该处理后就可以得到和官方版本具有同样性能的SDL.dll了。
你的include/SDL_config.h,应该看起来如下面所示:
#ifndef _SDL_config_h #define _SDL_config_h /* This is a set of defines to configure the SDL features */ /* General platform specific identifiers */ #include "SDL_platform.h" /* Make sure that this isn't included by Visual C++ */ #ifdef _MSC_VER #error You should copy include/SDL_config.h.default to include/SDL_config.h #endif /* C language features */ /* #undef const */ /* #undef inline */ /* #undef volatile */ /* C datatypes */ /* #undef size_t */ /* #undef int8_t */ /* #undef uint8_t */ /* #undef int16_t */ /* #undef uint16_t */ /* #undef int32_t */ /* #undef uint32_t */ /* #undef int64_t */ /* #undef uint64_t */ /* #undef uintptr_t */ #define SDL_HAS_64BIT_TYPE 1 /* Endianness */ #define SDL_BYTEORDER 1234 /* Comment this if you want to build without any C library requirements */ #define HAVE_LIBC 1 #if HAVE_LIBC /* Useful headers */ /* #undef HAVE_ALLOCA_H */ #define HAVE_SYS_TYPES_H 1 #define HAVE_STDIO_H 1 #define STDC_HEADERS 1 #define HAVE_STDLIB_H 1 #define HAVE_STDARG_H 1 #define HAVE_MALLOC_H 1 #define HAVE_MEMORY_H 1 #define HAVE_STRING_H 1 #define HAVE_STRINGS_H 1 #define HAVE_INTTYPES_H 1 #define HAVE_STDINT_H 1 #define HAVE_CTYPE_H 1 #define HAVE_MATH_H 1 /* #undef HAVE_ICONV_H */ #define HAVE_SIGNAL_H 1 /* #undef HAVE_ALTIVEC_H */ /* C library functions */ #define HAVE_MALLOC 1 #define HAVE_CALLOC 1 #define HAVE_REALLOC 1 #define HAVE_FREE 1 /* #undef HAVE_ALLOCA */ #ifndef _WIN32 /* Don't use C runtime versions of these on Windows */ #define HAVE_GETENV 1 #define HAVE_PUTENV 1 /* #undef HAVE_UNSETENV */ #endif #define HAVE_QSORT 1 #define HAVE_ABS 1 /* #undef HAVE_BCOPY */ #define HAVE_MEMSET 1 #define HAVE_MEMCPY 1 #define HAVE_MEMMOVE 1 #define HAVE_MEMCMP 1 #define HAVE_STRLEN 1 /* #undef HAVE_STRLCPY */ /* #undef HAVE_STRLCAT */ #define HAVE_STRDUP 1 #define HAVE__STRREV 1 #define HAVE__STRUPR 1 #define HAVE__STRLWR 1 /* #undef HAVE_INDEX */ /* #undef HAVE_RINDEX */ #define HAVE_STRCHR 1 #define HAVE_STRRCHR 1 #define HAVE_STRSTR 1 #define HAVE_ITOA 1 #define HAVE__LTOA 1 /* #undef HAVE__UITOA */ #define HAVE__ULTOA 1 #define HAVE_STRTOL 1 #define HAVE_STRTOUL 1 #define HAVE__I64TOA 1 #define HAVE__UI64TOA 1 #define HAVE_STRTOLL 1 #define HAVE_STRTOULL 1 #define HAVE_STRTOD 1 #define HAVE_ATOI 1 #define HAVE_ATOF 1 #define HAVE_STRCMP 1 #define HAVE_STRNCMP 1 #define HAVE__STRICMP 1 #define HAVE_STRCASECMP 1 #define HAVE__STRNICMP 1 #define HAVE_STRNCASECMP 1 #define HAVE_SSCANF 1 #define HAVE_SNPRINTF 1 #define HAVE_VSNPRINTF 1 /* #undef HAVE_ICONV */ /* #undef HAVE_SIGACTION */ /* #undef HAVE_SETJMP */ /* #undef HAVE_NANOSLEEP */ /* #undef HAVE_CLOCK_GETTIME */ /* #undef HAVE_GETPAGESIZE */ /* #undef HAVE_MPROTECT */ #else /* We may need some replacement for stdarg.h here */ #include #endif /* HAVE_LIBC */ /* Allow disabling of core subsystems */ /* #undef SDL_AUDIO_DISABLED */ /* #undef SDL_CDROM_DISABLED */ /* #undef SDL_CPUINFO_DISABLED */ /* #undef SDL_EVENTS_DISABLED */ /* #undef SDL_FILE_DISABLED */ /* #undef SDL_JOYSTICK_DISABLED */ /* #undef SDL_LOADSO_DISABLED */ /* #undef SDL_THREADS_DISABLED */ /* #undef SDL_TIMERS_DISABLED */ /* #undef SDL_VIDEO_DISABLED */ /* Enable various audio drivers */ /* #undef SDL_AUDIO_DRIVER_ALSA */ /* #undef SDL_AUDIO_DRIVER_ALSA_DYNAMIC */ /* #undef SDL_AUDIO_DRIVER_ARTS */ /* #undef SDL_AUDIO_DRIVER_ARTS_DYNAMIC */ /* #undef SDL_AUDIO_DRIVER_BAUDIO */ /* #undef SDL_AUDIO_DRIVER_BSD */ /* #undef SDL_AUDIO_DRIVER_COREAUDIO */ /* #undef SDL_AUDIO_DRIVER_DART */ /* #undef SDL_AUDIO_DRIVER_DC */ #define SDL_AUDIO_DRIVER_DISK 1 #define SDL_AUDIO_DRIVER_DUMMY 1 /* #undef SDL_AUDIO_DRIVER_DMEDIA */ #define SDL_AUDIO_DRIVER_DSOUND 1 /* #undef SDL_AUDIO_DRIVER_PULSE */ /* #undef SDL_AUDIO_DRIVER_PULSE_DYNAMIC */ /* #undef SDL_AUDIO_DRIVER_ESD */ /* #undef SDL_AUDIO_DRIVER_ESD_DYNAMIC */ /* #undef SDL_AUDIO_DRIVER_MINT */ /* #undef SDL_AUDIO_DRIVER_MMEAUDIO */ /* #undef SDL_AUDIO_DRIVER_NAS */ /* #undef SDL_AUDIO_DRIVER_NAS_DYNAMIC */ /* #undef SDL_AUDIO_DRIVER_OSS */ /* #undef SDL_AUDIO_DRIVER_OSS_SOUNDCARD_H */ /* #undef SDL_AUDIO_DRIVER_PAUD */ /* #undef SDL_AUDIO_DRIVER_QNXNTO */ /* #undef SDL_AUDIO_DRIVER_SNDMGR */ /* #undef SDL_AUDIO_DRIVER_SUNAUDIO */ #define SDL_AUDIO_DRIVER_WAVEOUT 1 /* Enable various cdrom drivers */ /* #undef SDL_CDROM_AIX */ /* #undef SDL_CDROM_BEOS */ /* #undef SDL_CDROM_BSDI */ /* #undef SDL_CDROM_DC */ /* #undef SDL_CDROM_DUMMY */ /* #undef SDL_CDROM_FREEBSD */ /* #undef SDL_CDROM_LINUX */ /* #undef SDL_CDROM_MACOS */ /* #undef SDL_CDROM_MACOSX */ /* #undef SDL_CDROM_MINT */ /* #undef SDL_CDROM_OPENBSD */ /* #undef SDL_CDROM_OS2 */ /* #undef SDL_CDROM_OSF */ /* #undef SDL_CDROM_QNX */ #define SDL_CDROM_WIN32 1 /* Enable various input drivers */ /* #undef SDL_INPUT_LINUXEV */ /* #undef SDL_INPUT_TSLIB */ /* #undef SDL_JOYSTICK_BEOS */ /* #undef SDL_JOYSTICK_DC */ /* #undef SDL_JOYSTICK_DUMMY */ /* #undef SDL_JOYSTICK_IOKIT */ /* #undef SDL_JOYSTICK_LINUX */ /* #undef SDL_JOYSTICK_MACOS */ /* #undef SDL_JOYSTICK_MINT */ /* #undef SDL_JOYSTICK_OS2 */ /* #undef SDL_JOYSTICK_RISCOS */ #define SDL_JOYSTICK_WINMM 1 /* #undef SDL_JOYSTICK_USBHID */ /* #undef SDL_JOYSTICK_USBHID_MACHINE_JOYSTICK_H */ /* Enable various shared object loading systems */ /* #undef SDL_LOADSO_BEOS */ /* #undef SDL_LOADSO_DLCOMPAT */ /* #undef SDL_LOADSO_DLOPEN */ /* #undef SDL_LOADSO_DUMMY */ /* #undef SDL_LOADSO_LDG */ /* #undef SDL_LOADSO_MACOS */ /* #undef SDL_LOADSO_OS2 */ #define SDL_LOADSO_WIN32 1 /* Enable various threading systems */ /* #undef SDL_THREAD_BEOS */ /* #undef SDL_THREAD_DC */ /* #undef SDL_THREAD_OS2 */ /* #undef SDL_THREAD_PTH */ /* #undef SDL_THREAD_PTHREAD */ /* #undef SDL_THREAD_PTHREAD_RECURSIVE_MUTEX */ /* #undef SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP */ /* #undef SDL_THREAD_SPROC */ #define SDL_THREAD_WIN32 1 /* Enable various timer systems */ /* #undef SDL_TIMER_BEOS */ /* #undef SDL_TIMER_DC */ /* #undef SDL_TIMER_DUMMY */ /* #undef SDL_TIMER_MACOS */ /* #undef SDL_TIMER_MINT */ /* #undef SDL_TIMER_OS2 */ /* #undef SDL_TIMER_RISCOS */ /* #undef SDL_TIMER_UNIX */ #define SDL_TIMER_WIN32 1 /* #undef SDL_TIMER_WINCE */ /* Enable various video drivers */ /* #undef SDL_VIDEO_DRIVER_AALIB */ /* #undef SDL_VIDEO_DRIVER_BWINDOW */ /* #undef SDL_VIDEO_DRIVER_CACA */ /* #undef SDL_VIDEO_DRIVER_DC */ #define SDL_VIDEO_DRIVER_DDRAW 1 /* #undef SDL_VIDEO_DRIVER_DGA */ /* #undef SDL_VIDEO_DRIVER_DIRECTFB */ /* #undef SDL_VIDEO_DRIVER_DRAWSPROCKET */ #define SDL_VIDEO_DRIVER_DUMMY 1 /* #undef SDL_VIDEO_DRIVER_FBCON */ /* #undef SDL_VIDEO_DRIVER_GAPI */ /* #undef SDL_VIDEO_DRIVER_GEM */ /* #undef SDL_VIDEO_DRIVER_GGI */ /* #undef SDL_VIDEO_DRIVER_IPOD */ /* #undef SDL_VIDEO_DRIVER_NANOX */ /* #undef SDL_VIDEO_DRIVER_OS2FS */ /* #undef SDL_VIDEO_DRIVER_PHOTON */ /* #undef SDL_VIDEO_DRIVER_PICOGUI */ /* #undef SDL_VIDEO_DRIVER_PS2GS */ /* #undef SDL_VIDEO_DRIVER_PS3 */ /* #undef SDL_VIDEO_DRIVER_QTOPIA */ /* #undef SDL_VIDEO_DRIVER_QUARTZ */ /* #undef SDL_VIDEO_DRIVER_RISCOS */ /* #undef SDL_VIDEO_DRIVER_SVGALIB */ /* #undef SDL_VIDEO_DRIVER_TOOLBOX */ /* #undef SDL_VIDEO_DRIVER_VGL */ #define SDL_VIDEO_DRIVER_WINDIB 1 /* #undef SDL_VIDEO_DRIVER_WSCONS */ /* #undef SDL_VIDEO_DRIVER_X11 */ /* #undef SDL_VIDEO_DRIVER_X11_DGAMOUSE */ /* #undef SDL_VIDEO_DRIVER_X11_DYNAMIC */ /* #undef SDL_VIDEO_DRIVER_X11_DYNAMIC_XEXT */ /* #undef SDL_VIDEO_DRIVER_X11_DYNAMIC_XRANDR */ /* #undef SDL_VIDEO_DRIVER_X11_DYNAMIC_XRENDER */ /* #undef SDL_VIDEO_DRIVER_X11_VIDMODE */ /* #undef SDL_VIDEO_DRIVER_X11_XINERAMA */ /* #undef SDL_VIDEO_DRIVER_X11_XME */ /* #undef SDL_VIDEO_DRIVER_X11_XRANDR */ /* #undef SDL_VIDEO_DRIVER_X11_XV */ /* #undef SDL_VIDEO_DRIVER_XBIOS */ /* Enable OpenGL support */ #define SDL_VIDEO_OPENGL 1 /* #undef SDL_VIDEO_OPENGL_GLX */ #define SDL_VIDEO_OPENGL_WGL 1 /* #undef SDL_VIDEO_OPENGL_OSMESA */ /* #undef SDL_VIDEO_OPENGL_OSMESA_DYNAMIC */ /* Disable screensaver */ #define SDL_VIDEO_DISABLE_SCREENSAVER 1 /* Enable assembly routines */ #define SDL_ASSEMBLY_ROUTINES 1 #define SDL_HERMES_BLITTERS 1 /* #undef SDL_ALTIVEC_BLITTERS */ #endif /* _SDL_config_h */
注意其中的：
#define SDL_AUDIO_DRIVER_DSOUND 1
#define SDL_VIDEO_DRIVER_DDRAW 1