src/video/dummy/SDL_nullvideo.c

   1 /*
   2     SDL - Simple DirectMedia Layer
   3     Copyright (C) 1997-2009 Sam Lantinga
   4
   5     This library is free software; you can redistribute it and/or
   6     modify it under the terms of the GNU Lesser General Public
   7     License as published by the Free Software Foundation; either
   8     version 2.1 of the License, or (at your option) any later version.
   9
  10     This library is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13     Lesser General Public License for more details.
  14
  15     You should have received a copy of the GNU Lesser General Public
  16     License along with this library; if not, write to the Free Software
  17     Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18
  19     Sam Lantinga
  20     slouken@libsdl.org
  21 */
  22 #include "SDL_config.h"
  23
  24 /* Dummy SDL video driver implementation; this is just enough to make an
  25  *  SDL-based application THINK it's got a working video driver, for
  26  *  applications that call SDL_Init(SDL_INIT_VIDEO) when they don't need it,
  27  *  and also for use as a collection of stubs when porting SDL to a new
  28  *  platform for which you haven't yet written a valid video driver.
  29  *
  30  * This is also a great way to determine bottlenecks: if you think that SDL
  31  *  is a performance problem for a given platform, enable this driver, and
  32  *  then see if your application runs faster without video overhead.
  33  *
  34  * Initial work by Ryan C. Gordon (icculus@icculus.org). A good portion
  35  *  of this was cut-and-pasted from Stephane Peter's work in the AAlib
  36  *  SDL video driver.  Renamed to "DUMMY" by Sam Lantinga.
  37  */
  38
  39 #include "SDL_video.h"
  40 #include "SDL_mouse.h"
  41 #include "../SDL_sysvideo.h"
  42 #include "../SDL_pixels_c.h"
  43 #include "../../events/SDL_events_c.h"
  44
  45 #include "SDL_nullvideo.h"
  46 #include "SDL_nullevents_c.h"
  47 #include "SDL_nullmouse_c.h"
  48
  49 #define DUMMYVID_DRIVER_NAME "dummy"
  50
  51 /* Initialization/Query functions */
  52 static int DUMMY_VideoInit(_THIS, SDL_PixelFormat *vformat);
  53 static SDL_Rect **DUMMY_ListModes(_THIS, SDL_PixelFormat *format, Uint32 flags);
  54 static SDL_Surface *DUMMY_SetVideoMode(_THIS, SDL_Surface *current, int width, int height, int bpp, Uint32 flags);
  55 static int DUMMY_SetColors(_THIS, int firstcolor, int ncolors, SDL_Color *colors);
  56 static void DUMMY_VideoQuit(_THIS);
  57
  58 /* Hardware surface functions */
  59 static int DUMMY_AllocHWSurface(_THIS, SDL_Surface *surface);
  60 static int DUMMY_LockHWSurface(_THIS, SDL_Surface *surface);
  61 static void DUMMY_UnlockHWSurface(_THIS, SDL_Surface *surface);
  62 static void DUMMY_FreeHWSurface(_THIS, SDL_Surface *surface);
  63
  64 /* etc. */
  65 static void DUMMY_UpdateRects(_THIS, int numrects, SDL_Rect *rects);
  66
  67 /* DUMMY driver bootstrap functions */
  68
  69 static int DUMMY_Available(void)
  70 {
  71         const char *envr = SDL_getenv("SDL_VIDEODRIVER");
  72         if ((envr) && (SDL_strcmp(envr, DUMMYVID_DRIVER_NAME) == 0)) {
  73                 return(1);
  74         }
  75
  76         return(0);
  77 }
  78
  79 static void DUMMY_DeleteDevice(SDL_VideoDevice *device)
  80 {
  81         SDL_free(device->hidden);
  82         SDL_free(device);
  83 }
  84
  85 static SDL_VideoDevice *DUMMY_CreateDevice(int devindex)
  86 {
  87         SDL_VideoDevice *device;
  88
  89         /* Initialize all variables that we clean on shutdown */
  90         device = (SDL_VideoDevice *)SDL_malloc(sizeof(SDL_VideoDevice));
  91         if ( device ) {
  92                 SDL_memset(device, 0, (sizeof *device));
  93                 device->hidden = (struct SDL_PrivateVideoData *)
  94                                 SDL_malloc((sizeof *device->hidden));
  95         }
  96         if ( (device == NULL) || (device->hidden == NULL) ) {
  97                 SDL_OutOfMemory();
  98                 if ( device ) {
  99                         SDL_free(device);
 100                 }
 101                 return(0);
 102         }
 103         SDL_memset(device->hidden, 0, (sizeof *device->hidden));
 104
 105         /* Set the function pointers */
 106         device->VideoInit = DUMMY_VideoInit;
 107         device->ListModes = DUMMY_ListModes;
 108         device->SetVideoMode = DUMMY_SetVideoMode;
 109         device->CreateYUVOverlay = NULL;
 110         device->SetColors = DUMMY_SetColors;
 111         device->UpdateRects = DUMMY_UpdateRects;
 112         device->VideoQuit = DUMMY_VideoQuit;
 113         device->AllocHWSurface = DUMMY_AllocHWSurface;
 114         device->CheckHWBlit = NULL;
 115         device->FillHWRect = NULL;
 116         device->SetHWColorKey = NULL;
 117         device->SetHWAlpha = NULL;
 118         device->LockHWSurface = DUMMY_LockHWSurface;
 119         device->UnlockHWSurface = DUMMY_UnlockHWSurface;
 120         device->FlipHWSurface = NULL;
 121         device->FreeHWSurface = DUMMY_FreeHWSurface;
 122         device->SetCaption = NULL;
 123         device->SetIcon = NULL;
 124         device->IconifyWindow = NULL;
 125         device->GrabInput = NULL;
 126         device->GetWMInfo = NULL;
 127         device->InitOSKeymap = DUMMY_InitOSKeymap;
 128         device->PumpEvents = DUMMY_PumpEvents;
 129
 130         device->free = DUMMY_DeleteDevice;
 131
 132         return device;
 133 }
 134
 135 VideoBootStrap DUMMY_bootstrap = {
 136         DUMMYVID_DRIVER_NAME, "SDL dummy video driver",
 137         DUMMY_Available, DUMMY_CreateDevice
 138 };
 139
 140
 141 int DUMMY_VideoInit(_THIS, SDL_PixelFormat *vformat)
 142 {
 143         /*
 144         fprintf(stderr, "WARNING: You are using the SDL dummy video driver!\n");
 145         */
 146
 147         /* Determine the screen depth (use default 8-bit depth) */
 148         /* we change this during the SDL_SetVideoMode implementation... */
 149         vformat->BitsPerPixel = 8;
 150         vformat->BytesPerPixel = 1;
 151
 152         /* We're done! */
 153         return(0);
 154 }
 155
 156 SDL_Rect **DUMMY_ListModes(_THIS, SDL_PixelFormat *format, Uint32 flags)
 157 {
 158          return (SDL_Rect **) -1;
 159 }
 160
 161 SDL_Surface *DUMMY_SetVideoMode(_THIS, SDL_Surface *current,
 162                                 int width, int height, int bpp, Uint32 flags)
 163 {
 164         if ( this->hidden->buffer ) {
 165                 SDL_free( this->hidden->buffer );
 166         }
 167
 168         this->hidden->buffer = SDL_malloc(width * height * (bpp / 8));
 169         if ( ! this->hidden->buffer ) {
 170                 SDL_SetError("Couldn't allocate buffer for requested mode");
 171                 return(NULL);
 172         }
 173
 174 /*      printf("Setting mode %dx%d\n", width, height); */
 175
 176         SDL_memset(this->hidden->buffer, 0, width * height * (bpp / 8));
 177
 178         /* Allocate the new pixel format for the screen */
 179         if ( ! SDL_ReallocFormat(current, bpp, 0, 0, 0, 0) ) {
 180                 SDL_free(this->hidden->buffer);
 181                 this->hidden->buffer = NULL;
 182                 SDL_SetError("Couldn't allocate new pixel format for requested mode");
 183                 return(NULL);
 184         }
 185
 186         /* Set up the new mode framebuffer */
 187         current->flags = flags & SDL_FULLSCREEN;
 188         this->hidden->w = current->w = width;
 189         this->hidden->h = current->h = height;
 190         current->pitch = current->w * (bpp / 8);
 191         current->pixels = this->hidden->buffer;
 192
 193         /* We're done */
 194         return(current);
 195 }
 196
 197 /* We don't actually allow hardware surfaces other than the main one */
 198 static int DUMMY_AllocHWSurface(_THIS, SDL_Surface *surface)
 199 {
 200         return(-1);
 201 }
 202 static void DUMMY_FreeHWSurface(_THIS, SDL_Surface *surface)
 203 {
 204         return;
 205 }
 206
 207 /* We need to wait for vertical retrace on page flipped displays */
 208 static int DUMMY_LockHWSurface(_THIS, SDL_Surface *surface)
 209 {
 210         return(0);
 211 }
 212
 213 static void DUMMY_UnlockHWSurface(_THIS, SDL_Surface *surface)
 214 {
 215         return;
 216 }
 217
 218 static void DUMMY_UpdateRects(_THIS, int numrects, SDL_Rect *rects)
 219 {
 220         /* do nothing. */
 221 }
 222
 223 int DUMMY_SetColors(_THIS, int firstcolor, int ncolors, SDL_Color *colors)
 224 {
 225         /* do nothing of note. */
 226         return(1);
 227 }
 228
 229 /* Note:  If we are terminated, this could be called in the middle of
 230    another SDL video routine -- notably UpdateRects.
 231 */
 232 void DUMMY_VideoQuit(_THIS)
 233 {
 234         if (this->screen->pixels != NULL)
 235         {
 236                 SDL_free(this->screen->pixels);
 237                 this->screen->pixels = NULL;
 238         }
 239 }