Atlas - SDL_nullvideo.c
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[FILE BEGIN]
1/*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2026 Sam Lantinga <[email protected]>
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#ifdef 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 ([email protected]). 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_sysvideo.h"
41#include "../SDL_pixels_c.h"
42#include "../../events/SDL_events_c.h"
43#ifdef SDL_INPUT_LINUXEV
44#include "../../core/linux/SDL_evdev.h"
45#endif
46
47#include "SDL_nullvideo.h"
48#include "SDL_nullevents_c.h"
49#include "SDL_nullframebuffer_c.h"
50
51#define DUMMYVID_DRIVER_NAME       "dummy"
52#define DUMMYVID_DRIVER_EVDEV_NAME "evdev"
53
54// Initialization/Query functions
55static bool DUMMY_VideoInitCommon(SDL_VideoDevice *_this);
56static bool DUMMY_VideoInit(SDL_VideoDevice *_this);
57static void DUMMY_VideoQuit(SDL_VideoDevice *_this);
58#ifdef SDL_INPUT_LINUXEV
59static bool DUMMY_EVDEV_VideoInit(SDL_VideoDevice *_this);
60static void DUMMY_EVDEV_VideoQuit(SDL_VideoDevice *_this);
61#endif
62
63static bool DUMMY_SetWindowPosition(SDL_VideoDevice *_this, SDL_Window *window)
64{
65    SDL_SendWindowEvent(window, SDL_EVENT_WINDOW_MOVED, window->pending.x, window->pending.y);
66    return true;
67}
68
69static void DUMMY_SetWindowSize(SDL_VideoDevice *_this, SDL_Window *window)
70{
71    SDL_SendWindowEvent(window, SDL_EVENT_WINDOW_RESIZED, window->pending.w, window->pending.h);
72}
73
74// DUMMY driver bootstrap functions
75
76static bool DUMMY_Available(const char *drivername)
77{
78    const char *hint = SDL_GetHint(SDL_HINT_VIDEO_DRIVER);
79    if (hint && SDL_strstr(hint, drivername) != NULL) {
80        return true;
81    }
82    return false;
83}
84
85static void DUMMY_DeleteDevice(SDL_VideoDevice *device)
86{
87    SDL_free(device);
88}
89
90static SDL_VideoDevice *DUMMY_InternalCreateDevice(const char *enable_hint)
91{
92    SDL_VideoDevice *device;
93
94    if (!DUMMY_Available(enable_hint)) {
95        return NULL;
96    }
97
98    // Initialize all variables that we clean on shutdown
99    device = (SDL_VideoDevice *)SDL_calloc(1, sizeof(SDL_VideoDevice));
100    if (!device) {
101        return NULL;
102    }
103
104    // Set the function pointers
105    device->VideoInit = DUMMY_VideoInit;
106    device->VideoQuit = DUMMY_VideoQuit;
107    device->PumpEvents = DUMMY_PumpEvents;
108    device->SetWindowSize = DUMMY_SetWindowSize;
109    device->SetWindowPosition = DUMMY_SetWindowPosition;
110    device->CreateWindowFramebuffer = SDL_DUMMY_CreateWindowFramebuffer;
111    device->UpdateWindowFramebuffer = SDL_DUMMY_UpdateWindowFramebuffer;
112    device->DestroyWindowFramebuffer = SDL_DUMMY_DestroyWindowFramebuffer;
113    device->free = DUMMY_DeleteDevice;
114
115    return device;
116}
117
118static SDL_VideoDevice *DUMMY_CreateDevice(void)
119{
120    return DUMMY_InternalCreateDevice(DUMMYVID_DRIVER_NAME);
121}
122
123VideoBootStrap DUMMY_bootstrap = {
124    DUMMYVID_DRIVER_NAME, "SDL dummy video driver",
125    DUMMY_CreateDevice,
126    NULL, // no ShowMessageBox implementation
127    false
128};
129
130#ifdef SDL_INPUT_LINUXEV
131
132static bool DUMMY_EVDEV_VideoInit(SDL_VideoDevice *_this)
133{
134    if (!DUMMY_VideoInitCommon(_this)) {
135        return false;
136    }
137
138    SDL_EVDEV_Init();
139    return true;
140}
141
142static void DUMMY_EVDEV_VideoQuit(SDL_VideoDevice *_this)
143{
144    SDL_EVDEV_Quit();
145}
146
147static void DUMMY_EVDEV_Poll(SDL_VideoDevice *_this)
148{
149    (void)_this;
150    SDL_EVDEV_Poll();
151}
152
153static SDL_VideoDevice *DUMMY_EVDEV_CreateDevice(void)
154{
155    SDL_VideoDevice *device = DUMMY_InternalCreateDevice(DUMMYVID_DRIVER_EVDEV_NAME);
156    if (device) {
157        device->VideoInit = DUMMY_EVDEV_VideoInit;
158        device->VideoQuit = DUMMY_EVDEV_VideoQuit;
159        device->PumpEvents = DUMMY_EVDEV_Poll;
160    }
161    return device;
162}
163
164VideoBootStrap DUMMY_evdev_bootstrap = {
165    DUMMYVID_DRIVER_EVDEV_NAME, "SDL dummy video driver with evdev",
166    DUMMY_EVDEV_CreateDevice,
167    NULL, // no ShowMessageBox implementation
168    false
169};
170
171#endif // SDL_INPUT_LINUXEV
172
173static bool DUMMY_SetRelativeMouseMode(bool enabled)
174{
175    return true;
176}
177
178bool DUMMY_VideoInitCommon(SDL_VideoDevice *_this)
179{
180    SDL_DisplayMode mode;
181
182    // Use a fake 32-bpp desktop mode
183    SDL_zero(mode);
184    mode.format = SDL_PIXELFORMAT_XRGB8888;
185    mode.w = 1024;
186    mode.h = 768;
187    if (SDL_AddBasicVideoDisplay(&mode) == 0) {
188        return false;
189    }
190
191    return true;
192}
193
194bool DUMMY_VideoInit(SDL_VideoDevice *_this)
195{
196    if (!DUMMY_VideoInitCommon(_this)) {
197        return false;
198    }
199
200    SDL_GetMouse()->SetRelativeMouseMode = DUMMY_SetRelativeMouseMode;
201    return true;
202}
203
204void DUMMY_VideoQuit(SDL_VideoDevice *_this)
205{
206}
207
208#endif // SDL_VIDEO_DRIVER_DUMMY
209
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