SDL  2.0
SDL_nullvideo.c
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
4 
5  This software is provided 'as-is', without any express or implied
6  warranty. In no event will the authors be held liable for any damages
7  arising from the use of this software.
8 
9  Permission is granted to anyone to use this software for any purpose,
10  including commercial applications, and to alter it and redistribute it
11  freely, subject to the following restrictions:
12 
13  1. The origin of this software must not be misrepresented; you must not
14  claim that you wrote the original software. If you use this software
15  in a product, an acknowledgment in the product documentation would be
16  appreciated but is not required.
17  2. Altered source versions must be plainly marked as such, and must not be
18  misrepresented as being the original software.
19  3. This notice may not be removed or altered from any source distribution.
20 */
21 #include "../../SDL_internal.h"
22 
23 #if SDL_VIDEO_DRIVER_DUMMY
24 
25 /* Dummy SDL video driver implementation; this is just enough to make an
26  * SDL-based application THINK it's got a working video driver, for
27  * applications that call SDL_Init(SDL_INIT_VIDEO) when they don't need it,
28  * and also for use as a collection of stubs when porting SDL to a new
29  * platform for which you haven't yet written a valid video driver.
30  *
31  * This is also a great way to determine bottlenecks: if you think that SDL
32  * is a performance problem for a given platform, enable this driver, and
33  * then see if your application runs faster without video overhead.
34  *
35  * Initial work by Ryan C. Gordon (icculus@icculus.org). A good portion
36  * of this was cut-and-pasted from Stephane Peter's work in the AAlib
37  * SDL video driver. Renamed to "DUMMY" by Sam Lantinga.
38  */
39 
40 #include "SDL_video.h"
41 #include "SDL_mouse.h"
42 #include "../SDL_sysvideo.h"
43 #include "../SDL_pixels_c.h"
44 #include "../../events/SDL_events_c.h"
45 
46 #include "SDL_nullvideo.h"
47 #include "SDL_nullevents_c.h"
48 #include "SDL_nullframebuffer_c.h"
49 
50 #define DUMMYVID_DRIVER_NAME "dummy"
51 
52 /* Initialization/Query functions */
53 static int DUMMY_VideoInit(_THIS);
54 static int DUMMY_SetDisplayMode(_THIS, SDL_VideoDisplay * display, SDL_DisplayMode * mode);
55 static void DUMMY_VideoQuit(_THIS);
56 
57 /* DUMMY driver bootstrap functions */
58 
59 static int
60 DUMMY_Available(void)
61 {
62  const char *envr = SDL_getenv("SDL_VIDEODRIVER");
63  if ((envr) && (SDL_strcmp(envr, DUMMYVID_DRIVER_NAME) == 0)) {
64  return (1);
65  }
66 
67  return (0);
68 }
69 
70 static void
71 DUMMY_DeleteDevice(SDL_VideoDevice * device)
72 {
73  SDL_free(device);
74 }
75 
76 static SDL_VideoDevice *
77 DUMMY_CreateDevice(int devindex)
78 {
79  SDL_VideoDevice *device;
80 
81  /* Initialize all variables that we clean on shutdown */
82  device = (SDL_VideoDevice *) SDL_calloc(1, sizeof(SDL_VideoDevice));
83  if (!device) {
84  SDL_OutOfMemory();
85  return (0);
86  }
87  device->is_dummy = SDL_TRUE;
88 
89  /* Set the function pointers */
90  device->VideoInit = DUMMY_VideoInit;
91  device->VideoQuit = DUMMY_VideoQuit;
92  device->SetDisplayMode = DUMMY_SetDisplayMode;
93  device->PumpEvents = DUMMY_PumpEvents;
94  device->CreateWindowFramebuffer = SDL_DUMMY_CreateWindowFramebuffer;
95  device->UpdateWindowFramebuffer = SDL_DUMMY_UpdateWindowFramebuffer;
96  device->DestroyWindowFramebuffer = SDL_DUMMY_DestroyWindowFramebuffer;
97 
98  device->free = DUMMY_DeleteDevice;
99 
100  return device;
101 }
102 
103 VideoBootStrap DUMMY_bootstrap = {
104  DUMMYVID_DRIVER_NAME, "SDL dummy video driver",
105  DUMMY_Available, DUMMY_CreateDevice
106 };
107 
108 
109 int
110 DUMMY_VideoInit(_THIS)
111 {
112  SDL_DisplayMode mode;
113 
114  /* Use a fake 32-bpp desktop mode */
115  mode.format = SDL_PIXELFORMAT_RGB888;
116  mode.w = 1024;
117  mode.h = 768;
118  mode.refresh_rate = 0;
119  mode.driverdata = NULL;
120  if (SDL_AddBasicVideoDisplay(&mode) < 0) {
121  return -1;
122  }
123 
124  SDL_zero(mode);
125  SDL_AddDisplayMode(&_this->displays[0], &mode);
126 
127  /* We're done! */
128  return 0;
129 }
130 
131 static int
132 DUMMY_SetDisplayMode(_THIS, SDL_VideoDisplay * display, SDL_DisplayMode * mode)
133 {
134  return 0;
135 }
136 
137 void
138 DUMMY_VideoQuit(_THIS)
139 {
140 }
141 
142 #endif /* SDL_VIDEO_DRIVER_DUMMY */
143 
144 /* vi: set ts=4 sw=4 expandtab: */