/*
  Simple DirectMedia Layer
  Copyright (C) 2017, Mark Callow

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

/**
 *  \file SDL_vulkan.h
 *
 *  Header file for functions to creating Vulkan surfaces on SDL windows.
 */

#ifndef SDL_vulkan_h_
#define SDL_vulkan_h_

#include <SDL2/SDL_video.h>

#include <SDL2/begin_code.h>
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif

/* Avoid including vulkan.h, don't define VkInstance if it's already included */
#ifdef VULKAN_H_
#define NO_SDL_VULKAN_TYPEDEFS
#endif
#ifndef NO_SDL_VULKAN_TYPEDEFS
#define VK_DEFINE_HANDLE(object) typedef struct object##_T* object;

#if defined(__LP64__) || defined(_WIN64) || defined(__x86_64__) || defined(_M_X64) || defined(__ia64) || defined (_M_IA64) || defined(__aarch64__) || defined(__powerpc64__)
#define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef struct object##_T *object;
#else
#define VK_DEFINE_NON_DISPATCHABLE_HANDLE(object) typedef uint64_t object;
#endif

VK_DEFINE_HANDLE(VkInstance)
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkSurfaceKHR)

#endif /* !NO_SDL_VULKAN_TYPEDEFS */

typedef VkInstance SDL_vulkanInstance;
typedef VkSurfaceKHR SDL_vulkanSurface; /* for compatibility with Tizen */

/**
 *  \name Vulkan support functions
 *
 *  \note SDL_Vulkan_GetInstanceExtensions & SDL_Vulkan_CreateSurface API
 *        is compatable with Tizen's implementation of Vulkan in SDL.
 */
/* @{ */

/**
 * Dynamically load the Vulkan loader library.
 *
 * This should be called after initializing the video driver, but before
 * creating any Vulkan windows. If no Vulkan loader library is loaded, the
 * default library will be loaded upon creation of the first Vulkan window.
 *
 * It is fairly common for Vulkan applications to link with libvulkan instead
 * of explicitly loading it at run time. This will work with SDL provided the
 * application links to a dynamic library and both it and SDL use the same
 * search path.
 *
 * If you specify a non-NULL `path`, an application should retrieve all of the
 * Vulkan functions it uses from the dynamic library using
 * SDL_Vulkan_GetVkGetInstanceProcAddr unless you can guarantee `path` points
 * to the same vulkan loader library the application linked to.
 *
 * On Apple devices, if `path` is NULL, SDL will attempt to find the
 * `vkGetInstanceProcAddr` address within all the Mach-O images of the current
 * process. This is because it is fairly common for Vulkan applications to
 * link with libvulkan (and historically MoltenVK was provided as a static
 * library). If it is not found, on macOS, SDL will attempt to load
 * `vulkan.framework/vulkan`, `libvulkan.1.dylib`,
 * `MoltenVK.framework/MoltenVK`, and `libMoltenVK.dylib`, in that order. On
 * iOS, SDL will attempt to load `libMoltenVK.dylib`. Applications using a
 * dynamic framework or .dylib must ensure it is included in its application
 * bundle.
 *
 * On non-Apple devices, application linking with a static libvulkan is not
 * supported. Either do not link to the Vulkan loader or link to a dynamic
 * library version.
 *
 * \param path The platform dependent Vulkan loader library name or NULL
 * \returns 0 on success or -1 if the library couldn't be loaded; call
 *          SDL_GetError() for more information.
 *
 * \since This function is available since SDL 2.0.6.
 *
 * \sa SDL_Vulkan_GetVkInstanceProcAddr
 * \sa SDL_Vulkan_UnloadLibrary
 */
extern DECLSPEC int SDLCALL SDL_Vulkan_LoadLibrary(const char *path);

/**
 * Get the address of the `vkGetInstanceProcAddr` function.
 *
 * This should be called after either calling SDL_Vulkan_LoadLibrary() or
 * creating an SDL_Window with the `SDL_WINDOW_VULKAN` flag.
 *
 * \returns the function pointer for `vkGetInstanceProcAddr` or NULL on error.
 *
 * \since This function is available since SDL 2.0.6.
 */
extern DECLSPEC void *SDLCALL SDL_Vulkan_GetVkGetInstanceProcAddr(void);

/**
 * Unload the Vulkan library previously loaded by SDL_Vulkan_LoadLibrary()
 *
 * \since This function is available since SDL 2.0.6.
 *
 * \sa SDL_Vulkan_LoadLibrary
 */
extern DECLSPEC void SDLCALL SDL_Vulkan_UnloadLibrary(void);

/**
 * Get the names of the Vulkan instance extensions needed to create a surface
 * with SDL_Vulkan_CreateSurface.
 *
 * If `pNames` is NULL, then the number of required Vulkan instance extensions
 * is returned in `pCount`. Otherwise, `pCount` must point to a variable set
 * to the number of elements in the `pNames` array, and on return the variable
 * is overwritten with the number of names actually written to `pNames`. If
 * `pCount` is less than the number of required extensions, at most `pCount`
 * structures will be written. If `pCount` is smaller than the number of
 * required extensions, SDL_FALSE will be returned instead of SDL_TRUE, to
 * indicate that not all the required extensions were returned.
 *
 * The `window` parameter is currently needed to be valid as of SDL 2.0.8,
 * however, this parameter will likely be removed in future releases
 *
 * \param window A window for which the required Vulkan instance extensions
 *               should be retrieved (will be deprecated in a future release)
 * \param pCount A pointer to an unsigned int corresponding to the number of
 *               extensions to be returned
 * \param pNames NULL or a pointer to an array to be filled with required
 *               Vulkan instance extensions
 * \returns SDL_TRUE on success, SDL_FALSE on error.
 *
 * \since This function is available since SDL 2.0.6.
 *
 * \sa SDL_Vulkan_CreateSurface
 */
extern DECLSPEC SDL_bool SDLCALL SDL_Vulkan_GetInstanceExtensions(SDL_Window *window,
                                                                  unsigned int *pCount,
                                                                  const char **pNames);

/**
 * Create a Vulkan rendering surface for a window.
 *
 * The `window` must have been created with the `SDL_WINDOW_VULKAN` flag and
 * `instance` must have been created with extensions returned by
 * SDL_Vulkan_GetInstanceExtensions() enabled.
 *
 * \param window The window to which to attach the Vulkan surface
 * \param instance The Vulkan instance handle
 * \param surface A pointer to a VkSurfaceKHR handle to output the newly
 *                created surface
 * \returns SDL_TRUE on success, SDL_FALSE on error.
 *
 * \since This function is available since SDL 2.0.6.
 *
 * \sa SDL_Vulkan_GetInstanceExtensions
 * \sa SDL_Vulkan_GetDrawableSize
 */
extern DECLSPEC SDL_bool SDLCALL SDL_Vulkan_CreateSurface(SDL_Window *window,
                                                          VkInstance instance,
                                                          VkSurfaceKHR* surface);

/**
 * Get the size of the window's underlying drawable dimensions in pixels.
 *
 * This may differ from SDL_GetWindowSize() if we're rendering to a high-DPI
 * drawable, i.e. the window was created with `SDL_WINDOW_ALLOW_HIGHDPI` on a
 * platform with high-DPI support (Apple calls this "Retina"), and not
 * disabled by the `SDL_HINT_VIDEO_HIGHDPI_DISABLED` hint.
 *
 * \param window an SDL_Window for which the size is to be queried
 * \param w Pointer to the variable to write the width to or NULL
 * \param h Pointer to the variable to write the height to or NULL
 *
 * \since This function is available since SDL 2.0.6.
 *
 * \sa SDL_GetWindowSize
 * \sa SDL_CreateWindow
 * \sa SDL_Vulkan_CreateSurface
 */
extern DECLSPEC void SDLCALL SDL_Vulkan_GetDrawableSize(SDL_Window * window,
                                                        int *w, int *h);

/* @} *//* Vulkan support functions */

/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include <SDL2/close_code.h>

#endif /* SDL_vulkan_h_ */
