Added an OpenVR video driver (thanks @cnlohr!)

src/video/SDL_sysvideo.h

@@ -521,6 +521,7 @@ extern VideoBootStrap Emscripten_bootstrap;
 extern VideoBootStrap OFFSCREEN_bootstrap;
 extern VideoBootStrap NGAGE_bootstrap;
 extern VideoBootStrap QNX_bootstrap;
+extern VideoBootStrap OPENVR_bootstrap;
 
 // Use SDL_OnVideoThread() sparingly, to avoid regressions in use cases that currently happen to work
 extern bool SDL_OnVideoThread(void);

src/video/SDL_video.c

@@ -139,6 +139,9 @@ static VideoBootStrap *bootstrap[] = {
 #ifdef SDL_INPUT_LINUXEV
     &DUMMY_evdev_bootstrap,
 #endif
+#endif
+#ifdef SDL_VIDEO_DRIVER_OPENVR
+    &OPENVR_bootstrap,
 #endif
     NULL
 };
@@ -2339,6 +2342,10 @@ SDL_Window *SDL_CreateWindowWithProperties(SDL_PropertiesID props)
         flags |= SDL_DefaultGraphicsBackends(_this);
     }
 
+#if defined(SDL_VIDEO_OPENGL) && defined(SDL_VIDEO_DRIVER_OPENVR)
+    flags |= SDL_WINDOW_OPENGL;
+#endif
+
     if (flags & SDL_WINDOW_OPENGL) {
         if (!_this->GL_CreateContext) {
             SDL_ContextNotSupported("OpenGL");

src/video/openvr/SDL_openvrvideo.h

@@ -0,0 +1,109 @@
+#ifndef _SDL_OPENVRVIDEO_H
+#define _SDL_OPENVRVIDEO_H
+
+#ifdef SDL_VIDEO_DRIVER_WINDOWS
+#ifdef EXTERN_C
+#undef EXTERN_C
+#endif
+#define GL_APIENTRY
+#define GL_APICALL
+#endif
+
+// OpenVR has a LOT of unused variables that GCC will freak out on.
+#ifdef __GNUC__
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wunused-variable"
+#endif
+
+#include "openvr_capi.h"
+
+#ifdef __GNUC__
+#pragma GCC diagnostic pop
+#endif
+
+#include <stdint.h>
+
+#ifndef SDL_VIDEO_DRIVER_WINDOWS
+
+#include <GLES3/gl3.h>
+#include <GLES3/gl32.h>
+#include <EGL/egl.h>
+#include <GLES2/gl2.h>
+#include <GLES2/gl2ext.h>
+#include <GLES2/gl2ext.h>
+
+#endif
+
+
+typedef struct SDL_WindowData
+{
+#ifdef SDL_VIDEO_DRIVER_WINDOWS
+    SDL_Window *window;
+    HWND hwnd;
+    HWND parent;
+    HDC hdc;
+    HDC mdc;
+#else
+    int dummy;
+#endif
+} SDL_WindowData;
+
+typedef struct SDL_VideoData {
+    void * openVRLIB;
+    intptr_t vrtoken;
+    intptr_t (*FN_VR_InitInternal)( EVRInitError *peError, EVRApplicationType eType );
+    const char *(*FN_VR_GetVRInitErrorAsEnglishDescription)( EVRInitError error );
+    intptr_t (*FN_VR_GetGenericInterface)( const char *pchInterfaceVersion, EVRInitError *peError );
+
+    int is_buffer_rendering;
+
+    unsigned int overlaytexture;
+
+    unsigned int fbo, rbo;
+
+    int saved_texture_state;
+
+    struct VR_IVRSystem_FnTable *oSystem;
+    struct VR_IVROverlay_FnTable *oOverlay;
+	struct VR_IVRInput_FnTable * oInput;
+	VROverlayHandle_t overlayID, thumbID, cursorID;
+	
+	char * sOverlayName;
+
+	VRActionSetHandle_t input_action_set;
+	VRActionHandle_t * input_action_handles_buttons;
+	int input_action_handles_buttons_count;
+	VRActionHandle_t * input_action_handles_axes;
+	int input_action_handles_axes_count;
+	VRActionHandle_t input_action_handles_haptics[2];
+
+    bool bKeyboardShown;
+    bool bHasShownOverlay;
+    int targw, targh;
+    int last_targw, last_targh;
+    int swap_interval;
+
+    bool bDidCreateOverlay;
+	bool renderdoc_debugmarker_frame_end;
+	bool bIconOverridden;
+	
+	SDL_Window * window;
+	
+	SDL_Joystick *virtual_joystick;
+#ifdef SDL_VIDEO_DRIVER_WINDOWS
+    HDC hdc;
+    HGLRC hglrc;
+#else
+    EGLDisplay eglDpy;
+    EGLContext eglCtx;
+#endif
+} SDL_VideoData;
+
+
+typedef struct SDL_DisplayData
+{
+    int dummy;
+} SDL_DisplayData;
+
+
+#endif