sdlu.c

   1 /* SDL utils
   2  * Copyright (C) 2011  Kirill Smelkov <kirr@navytux.spb.ru>
   3  * Copyright (C) 2011  Marine Bridge and Navigation Systems (http://mns.spb.ru/)
   4  *
   5  * This library is free software: you can Use, Study, Modify and Redistribute
   6  * it under the terms of the GNU Lesser General Public License version 2.1, or
   7  * any later version. This library is distributed WITHOUT ANY WARRANTY. See
   8  * COPYING.LIB file for full License terms.
   9  */
  10
  11 #include "sdlu.h"
  12
  13 /* From SDL_yuvfuncs.h - last updated from SDL-1.2.14. KEEP IN SYNC.
  14  * TODO check SDL version at compile time.
  15  *
  16  * ---- 8< -----
  17  */
  18 typedef struct SDL_VideoDevice SDL_VideoDevice;
  19
  20 #ifndef _THIS
  21 #define _THIS   SDL_VideoDevice *_this
  22 #endif
  23 struct private_yuvhwfuncs {
  24     int (*Lock)(_THIS, SDL_Overlay *overlay);
  25     void (*Unlock)(_THIS, SDL_Overlay *overlay);
  26     int (*Display)(_THIS, SDL_Overlay *overlay, SDL_Rect *src, SDL_Rect *dst);
  27     void (*FreeHW)(_THIS, SDL_Overlay *overlay);
  28 };
  29
  30 /* ---- 8< ----- */
  31
  32
  33 /*
  34  * Determine SDL's current_video at runtime via temporarily faking overlay ->Lock hwfunc
  35  */
  36 static int SDLU_YUVDetectCurrentVideo_ViaLock(SDL_VideoDevice *_this, SDL_Overlay *overlay)
  37 {
  38     SDL_VideoDevice **pSDL_current_video = (SDL_VideoDevice **)overlay->hwdata;
  39     *pSDL_current_video = _this;    /* _this is set to current_video by SDL */
  40     return 0;   /* "locked" ok */
  41 }
  42
  43 static SDL_VideoDevice *SDLU_YUVCurrentVideo(SDL_Overlay *overlay)
  44 {
  45     SDL_VideoDevice *SDL_current_video;
  46
  47     int  (*yuvlock)   (SDL_VideoDevice *, SDL_Overlay *);
  48     struct private_yuvhwdata *hwdata;
  49
  50     yuvlock = overlay->hwfuncs->Lock;
  51     hwdata  = overlay->hwdata;
  52
  53     overlay->hwdata         = (struct private_yuvhwdata *)&SDL_current_video;
  54     overlay->hwfuncs->Lock  = SDLU_YUVDetectCurrentVideo_ViaLock;
  55
  56     SDL_current_video = NULL;
  57     SDL_LockYUVOverlay(overlay);
  58
  59     if (!SDL_current_video) {
  60         fprintf(stderr, "Can't determine SDL_current_video\n");   /* should not happen */
  61         abort();
  62     }
  63
  64     overlay->hwfuncs->Lock  = yuvlock;
  65     overlay->hwdata         = hwdata;
  66
  67     return SDL_current_video;
  68 }
  69
  70
  71 int SDLU_DisplayYUVOverlay(SDL_Overlay *overlay, SDL_Rect *srcrect, SDL_Rect *dstrect)
  72 {
  73     SDL_VideoDevice *video = SDLU_YUVCurrentVideo(overlay);
  74
  75     /* Just do hwfuncs dispatch like in SDL_DisplayYUVOverlay, without clipping prologue */
  76     return overlay->hwfuncs->Display(video, overlay, srcrect, dstrect);
  77 }