1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2025 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#ifdef SDL_VIDEO_DRIVER_OFFSCREEN
24
25/* Offscreen video driver is similar to dummy driver, however its purpose
26 * is enabling applications to use some of the SDL video functionality
27 * (notably context creation) while not requiring a display output.
28 *
29 * An example would be running a graphical program on a headless box
30 * for automated testing.
31 */
32
33#include "SDL_offscreenvideo.h"
34#include "SDL_offscreenevents_c.h"
35#include "SDL_offscreenframebuffer_c.h"
36#include "SDL_offscreenopengles.h"
37#include "SDL_offscreenvulkan.h"
38#include "SDL_offscreenwindow.h"
39
40#define OFFSCREENVID_DRIVER_NAME "offscreen"
41
42// Initialization/Query functions
43static bool OFFSCREEN_VideoInit(SDL_VideoDevice *_this);
44static bool OFFSCREEN_SetDisplayMode(SDL_VideoDevice *_this, SDL_VideoDisplay *display, SDL_DisplayMode *mode);
45static void OFFSCREEN_VideoQuit(SDL_VideoDevice *_this);
46
47// OFFSCREEN driver bootstrap functions
48
49static void OFFSCREEN_DeleteDevice(SDL_VideoDevice *device)
50{
51 SDL_free(device);
52}
53
54static bool OFFSCREEN_Available(const char *enable_hint)
55{
56 const char *hint = SDL_GetHint(SDL_HINT_VIDEO_DRIVER);
57 if (hint) {
58 if (SDL_strcmp(hint, enable_hint) == 0) {
59 return true;
60 }
61 }
62 return false;
63}
64
65static SDL_VideoDevice *OFFSCREEN_CreateDevice(void)
66{
67 SDL_VideoDevice *device;
68
69 if (!OFFSCREEN_Available(OFFSCREENVID_DRIVER_NAME)) {
70 return NULL;
71 }
72
73 // Initialize all variables that we clean on shutdown
74 device = (SDL_VideoDevice *)SDL_calloc(1, sizeof(SDL_VideoDevice));
75 if (!device) {
76 return NULL;
77 }
78
79 // General video
80 device->VideoInit = OFFSCREEN_VideoInit;
81 device->VideoQuit = OFFSCREEN_VideoQuit;
82 device->SetDisplayMode = OFFSCREEN_SetDisplayMode;
83 device->PumpEvents = OFFSCREEN_PumpEvents;
84 device->CreateWindowFramebuffer = SDL_OFFSCREEN_CreateWindowFramebuffer;
85 device->UpdateWindowFramebuffer = SDL_OFFSCREEN_UpdateWindowFramebuffer;
86 device->DestroyWindowFramebuffer = SDL_OFFSCREEN_DestroyWindowFramebuffer;
87 device->free = OFFSCREEN_DeleteDevice;
88
89#ifdef SDL_VIDEO_OPENGL_EGL
90 // GL context
91 device->GL_SwapWindow = OFFSCREEN_GLES_SwapWindow;
92 device->GL_MakeCurrent = OFFSCREEN_GLES_MakeCurrent;
93 device->GL_CreateContext = OFFSCREEN_GLES_CreateContext;
94 device->GL_DestroyContext = OFFSCREEN_GLES_DestroyContext;
95 device->GL_LoadLibrary = OFFSCREEN_GLES_LoadLibrary;
96 device->GL_UnloadLibrary = OFFSCREEN_GLES_UnloadLibrary;
97 device->GL_GetProcAddress = OFFSCREEN_GLES_GetProcAddress;
98 device->GL_GetSwapInterval = OFFSCREEN_GLES_GetSwapInterval;
99 device->GL_SetSwapInterval = OFFSCREEN_GLES_SetSwapInterval;
100#endif
101
102#ifdef SDL_VIDEO_VULKAN
103 device->Vulkan_LoadLibrary = OFFSCREEN_Vulkan_LoadLibrary;
104 device->Vulkan_UnloadLibrary = OFFSCREEN_Vulkan_UnloadLibrary;
105 device->Vulkan_GetInstanceExtensions = OFFSCREEN_Vulkan_GetInstanceExtensions;
106 device->Vulkan_CreateSurface = OFFSCREEN_Vulkan_CreateSurface;
107 device->Vulkan_DestroySurface = OFFSCREEN_Vulkan_DestroySurface;
108#endif
109
110 // "Window"
111 device->CreateSDLWindow = OFFSCREEN_CreateWindow;
112 device->DestroyWindow = OFFSCREEN_DestroyWindow;
113 device->SetWindowSize = OFFSCREEN_SetWindowSize;
114
115 return device;
116}
117
118VideoBootStrap OFFSCREEN_bootstrap = {
119 OFFSCREENVID_DRIVER_NAME, "SDL offscreen video driver",
120 OFFSCREEN_CreateDevice,
121 NULL, // no ShowMessageBox implementation
122 false
123};
124
125static bool OFFSCREEN_VideoInit(SDL_VideoDevice *_this)
126{
127 SDL_DisplayMode mode;
128
129 // Use a fake 32-bpp desktop mode
130 SDL_zero(mode);
131 mode.format = SDL_PIXELFORMAT_XRGB8888;
132 mode.w = 1024;
133 mode.h = 768;
134 if (SDL_AddBasicVideoDisplay(&mode) == 0) {
135 return false;
136 }
137
138 // We're done!
139 return true;
140}
141
142static bool OFFSCREEN_SetDisplayMode(SDL_VideoDevice *_this, SDL_VideoDisplay *display, SDL_DisplayMode *mode)
143{
144 return true;
145}
146
147void OFFSCREEN_VideoQuit(SDL_VideoDevice *_this)
148{
149}
150
151#endif // SDL_VIDEO_DRIVER_OFFSCREEN
152