OpenTTD/src/video/sdl2_v.cpp

730 lines
20 KiB
C++

/*
* This file is part of OpenTTD.
* OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
* OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file sdl2_v.cpp Implementation of the SDL2 video driver. */
#include "../stdafx.h"
#include "../openttd.h"
#include "../gfx_func.h"
#include "../blitter/factory.hpp"
#include "../thread.h"
#include "../progress.h"
#include "../core/random_func.hpp"
#include "../core/math_func.hpp"
#include "../core/mem_func.hpp"
#include "../core/geometry_func.hpp"
#include "../fileio_func.h"
#include "../framerate_type.h"
#include "../window_func.h"
#include "sdl2_v.h"
#include <SDL.h>
#ifdef __EMSCRIPTEN__
# include <emscripten.h>
# include <emscripten/html5.h>
#endif
#include "../safeguards.h"
void VideoDriver_SDL_Base::MakeDirty(int left, int top, int width, int height)
{
Rect r = {left, top, left + width, top + height};
this->dirty_rect = BoundingRect(this->dirty_rect, r);
}
void VideoDriver_SDL_Base::CheckPaletteAnim()
{
if (!CopyPalette(this->local_palette)) return;
this->MakeDirty(0, 0, _screen.width, _screen.height);
}
static const Dimension default_resolutions[] = {
{ 640, 480 },
{ 800, 600 },
{ 1024, 768 },
{ 1152, 864 },
{ 1280, 800 },
{ 1280, 960 },
{ 1280, 1024 },
{ 1400, 1050 },
{ 1600, 1200 },
{ 1680, 1050 },
{ 1920, 1200 }
};
static void FindResolutions()
{
_resolutions.clear();
for (int display = 0; display < SDL_GetNumVideoDisplays(); display++) {
for (int i = 0; i < SDL_GetNumDisplayModes(display); i++) {
SDL_DisplayMode mode;
SDL_GetDisplayMode(display, i, &mode);
if (mode.w < 640 || mode.h < 480) continue;
if (std::find(_resolutions.begin(), _resolutions.end(), Dimension(mode.w, mode.h)) != _resolutions.end()) continue;
_resolutions.emplace_back(mode.w, mode.h);
}
}
/* We have found no resolutions, show the default list */
if (_resolutions.empty()) {
_resolutions.assign(std::begin(default_resolutions), std::end(default_resolutions));
}
SortResolutions();
}
static void GetAvailableVideoMode(uint *w, uint *h)
{
/* All modes available? */
if (!_fullscreen || _resolutions.empty()) return;
/* Is the wanted mode among the available modes? */
if (std::find(_resolutions.begin(), _resolutions.end(), Dimension(*w, *h)) != _resolutions.end()) return;
/* Use the closest possible resolution */
uint best = 0;
uint delta = Delta(_resolutions[0].width, *w) * Delta(_resolutions[0].height, *h);
for (uint i = 1; i != _resolutions.size(); ++i) {
uint newdelta = Delta(_resolutions[i].width, *w) * Delta(_resolutions[i].height, *h);
if (newdelta < delta) {
best = i;
delta = newdelta;
}
}
*w = _resolutions[best].width;
*h = _resolutions[best].height;
}
static uint FindStartupDisplay(uint startup_display)
{
int num_displays = SDL_GetNumVideoDisplays();
/* If the user indicated a valid monitor, use that. */
if (IsInsideBS(startup_display, 0, num_displays)) return startup_display;
/* Mouse position decides which display to use. */
int mx, my;
SDL_GetGlobalMouseState(&mx, &my);
for (int display = 0; display < num_displays; ++display) {
SDL_Rect r;
if (SDL_GetDisplayBounds(display, &r) == 0 && IsInsideBS(mx, r.x, r.w) && IsInsideBS(my, r.y, r.h)) {
Debug(driver, 1, "SDL2: Mouse is at ({}, {}), use display {} ({}, {}, {}, {})", mx, my, display, r.x, r.y, r.w, r.h);
return display;
}
}
return 0;
}
void VideoDriver_SDL_Base::ClientSizeChanged(int w, int h, bool force)
{
/* Allocate backing store of the new size. */
if (this->AllocateBackingStore(w, h, force)) {
CopyPalette(this->local_palette, true);
BlitterFactory::GetCurrentBlitter()->PostResize();
GameSizeChanged();
}
}
bool VideoDriver_SDL_Base::CreateMainWindow(uint w, uint h, uint flags)
{
if (this->sdl_window != nullptr) return true;
flags |= SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE;
if (_fullscreen) {
flags |= SDL_WINDOW_FULLSCREEN;
}
int x = SDL_WINDOWPOS_UNDEFINED, y = SDL_WINDOWPOS_UNDEFINED;
SDL_Rect r;
if (SDL_GetDisplayBounds(this->startup_display, &r) == 0) {
x = r.x + std::max(0, r.w - static_cast<int>(w)) / 2;
y = r.y + std::max(0, r.h - static_cast<int>(h)) / 4; // decent desktops have taskbars at the bottom
}
std::string caption = VideoDriver::GetCaption();
this->sdl_window = SDL_CreateWindow(
caption.c_str(),
x, y,
w, h,
flags);
if (this->sdl_window == nullptr) {
Debug(driver, 0, "SDL2: Couldn't allocate a window to draw on: {}", SDL_GetError());
return false;
}
std::string icon_path = FioFindFullPath(BASESET_DIR, "openttd.32.bmp");
if (!icon_path.empty()) {
/* Give the application an icon */
SDL_Surface *icon = SDL_LoadBMP(icon_path.c_str());
if (icon != nullptr) {
/* Get the colourkey, which will be magenta */
uint32_t rgbmap = SDL_MapRGB(icon->format, 255, 0, 255);
SDL_SetColorKey(icon, SDL_TRUE, rgbmap);
SDL_SetWindowIcon(this->sdl_window, icon);
SDL_FreeSurface(icon);
}
}
return true;
}
bool VideoDriver_SDL_Base::CreateMainSurface(uint w, uint h, bool resize)
{
GetAvailableVideoMode(&w, &h);
Debug(driver, 1, "SDL2: using mode {}x{}", w, h);
if (!this->CreateMainWindow(w, h)) return false;
if (resize) SDL_SetWindowSize(this->sdl_window, w, h);
this->ClientSizeChanged(w, h, true);
/* When in full screen, we will always have the mouse cursor
* within the window, even though SDL does not give us the
* appropriate event to know this. */
if (_fullscreen) _cursor.in_window = true;
return true;
}
bool VideoDriver_SDL_Base::ClaimMousePointer()
{
/* Emscripten never claims the pointer, so we do not need to change the cursor visibility. */
#ifndef __EMSCRIPTEN__
SDL_ShowCursor(0);
#endif
return true;
}
/**
* This is called to indicate that an edit box has gained focus, text input mode should be enabled.
*/
void VideoDriver_SDL_Base::EditBoxGainedFocus()
{
if (!this->edit_box_focused) {
SDL_StartTextInput();
this->edit_box_focused = true;
}
}
/**
* This is called to indicate that an edit box has lost focus, text input mode should be disabled.
*/
void VideoDriver_SDL_Base::EditBoxLostFocus()
{
if (this->edit_box_focused) {
SDL_StopTextInput();
this->edit_box_focused = false;
}
}
std::vector<int> VideoDriver_SDL_Base::GetListOfMonitorRefreshRates()
{
std::vector<int> rates = {};
for (int i = 0; i < SDL_GetNumVideoDisplays(); i++) {
SDL_DisplayMode mode = {};
if (SDL_GetDisplayMode(i, 0, &mode) != 0) continue;
if (mode.refresh_rate != 0) rates.push_back(mode.refresh_rate);
}
return rates;
}
struct SDLVkMapping {
SDL_Keycode vk_from;
uint8_t vk_count;
uint8_t map_to;
bool unprintable;
};
#define AS(x, z) {x, 0, z, false}
#define AM(x, y, z, w) {x, (uint8_t)(y - x), z, false}
#define AS_UP(x, z) {x, 0, z, true}
#define AM_UP(x, y, z, w) {x, (uint8_t)(y - x), z, true}
static const SDLVkMapping _vk_mapping[] = {
/* Pageup stuff + up/down */
AS_UP(SDLK_PAGEUP, WKC_PAGEUP),
AS_UP(SDLK_PAGEDOWN, WKC_PAGEDOWN),
AS_UP(SDLK_UP, WKC_UP),
AS_UP(SDLK_DOWN, WKC_DOWN),
AS_UP(SDLK_LEFT, WKC_LEFT),
AS_UP(SDLK_RIGHT, WKC_RIGHT),
AS_UP(SDLK_HOME, WKC_HOME),
AS_UP(SDLK_END, WKC_END),
AS_UP(SDLK_INSERT, WKC_INSERT),
AS_UP(SDLK_DELETE, WKC_DELETE),
/* Map letters & digits */
AM(SDLK_a, SDLK_z, 'A', 'Z'),
AM(SDLK_0, SDLK_9, '0', '9'),
AS_UP(SDLK_ESCAPE, WKC_ESC),
AS_UP(SDLK_PAUSE, WKC_PAUSE),
AS_UP(SDLK_BACKSPACE, WKC_BACKSPACE),
AS(SDLK_SPACE, WKC_SPACE),
AS(SDLK_RETURN, WKC_RETURN),
AS(SDLK_TAB, WKC_TAB),
/* Function keys */
AM_UP(SDLK_F1, SDLK_F12, WKC_F1, WKC_F12),
/* Numeric part. */
AM(SDLK_KP_0, SDLK_KP_9, '0', '9'),
AS(SDLK_KP_DIVIDE, WKC_NUM_DIV),
AS(SDLK_KP_MULTIPLY, WKC_NUM_MUL),
AS(SDLK_KP_MINUS, WKC_NUM_MINUS),
AS(SDLK_KP_PLUS, WKC_NUM_PLUS),
AS(SDLK_KP_ENTER, WKC_NUM_ENTER),
AS(SDLK_KP_PERIOD, WKC_NUM_DECIMAL),
/* Other non-letter keys */
AS(SDLK_SLASH, WKC_SLASH),
AS(SDLK_SEMICOLON, WKC_SEMICOLON),
AS(SDLK_EQUALS, WKC_EQUALS),
AS(SDLK_LEFTBRACKET, WKC_L_BRACKET),
AS(SDLK_BACKSLASH, WKC_BACKSLASH),
AS(SDLK_RIGHTBRACKET, WKC_R_BRACKET),
AS(SDLK_QUOTE, WKC_SINGLEQUOTE),
AS(SDLK_COMMA, WKC_COMMA),
AS(SDLK_MINUS, WKC_MINUS),
AS(SDLK_PERIOD, WKC_PERIOD)
};
static uint ConvertSdlKeyIntoMy(SDL_Keysym *sym, char32_t *character)
{
const SDLVkMapping *map;
uint key = 0;
bool unprintable = false;
for (map = _vk_mapping; map != endof(_vk_mapping); ++map) {
if ((uint)(sym->sym - map->vk_from) <= map->vk_count) {
key = sym->sym - map->vk_from + map->map_to;
unprintable = map->unprintable;
break;
}
}
/* check scancode for BACKQUOTE key, because we want the key left of "1", not anything else (on non-US keyboards) */
if (sym->scancode == SDL_SCANCODE_GRAVE) key = WKC_BACKQUOTE;
/* META are the command keys on mac */
if (sym->mod & KMOD_GUI) key |= WKC_META;
if (sym->mod & KMOD_SHIFT) key |= WKC_SHIFT;
if (sym->mod & KMOD_CTRL) key |= WKC_CTRL;
if (sym->mod & KMOD_ALT) key |= WKC_ALT;
/* The mod keys have no character. Prevent '?' */
if (sym->mod & KMOD_GUI ||
sym->mod & KMOD_CTRL ||
sym->mod & KMOD_ALT ||
unprintable) {
*character = WKC_NONE;
} else {
*character = sym->sym;
}
return key;
}
/**
* Like ConvertSdlKeyIntoMy(), but takes an SDL_Keycode as input
* instead of an SDL_Keysym.
*/
static uint ConvertSdlKeycodeIntoMy(SDL_Keycode kc)
{
const SDLVkMapping *map;
uint key = 0;
for (map = _vk_mapping; map != endof(_vk_mapping); ++map) {
if ((uint)(kc - map->vk_from) <= map->vk_count) {
key = kc - map->vk_from + map->map_to;
break;
}
}
/* check scancode for BACKQUOTE key, because we want the key left
* of "1", not anything else (on non-US keyboards) */
SDL_Scancode sc = SDL_GetScancodeFromKey(kc);
if (sc == SDL_SCANCODE_GRAVE) key = WKC_BACKQUOTE;
return key;
}
bool VideoDriver_SDL_Base::PollEvent()
{
SDL_Event ev;
if (!SDL_PollEvent(&ev)) return false;
switch (ev.type) {
case SDL_MOUSEMOTION: {
int32_t x = ev.motion.x;
int32_t y = ev.motion.y;
if (_cursor.fix_at) {
/* Get all queued mouse events now in case we have to warp the cursor. In the
* end, we only care about the current mouse position and not bygone events. */
while (SDL_PeepEvents(&ev, 1, SDL_GETEVENT, SDL_MOUSEMOTION, SDL_MOUSEMOTION)) {
x = ev.motion.x;
y = ev.motion.y;
}
}
if (_cursor.UpdateCursorPosition(x, y)) {
SDL_WarpMouseInWindow(this->sdl_window, _cursor.pos.x, _cursor.pos.y);
}
HandleMouseEvents();
break;
}
case SDL_MOUSEWHEEL:
if (ev.wheel.y > 0) {
_cursor.wheel--;
} else if (ev.wheel.y < 0) {
_cursor.wheel++;
}
break;
case SDL_MOUSEBUTTONDOWN:
if (_rightclick_emulate && SDL_GetModState() & KMOD_CTRL) {
ev.button.button = SDL_BUTTON_RIGHT;
}
switch (ev.button.button) {
case SDL_BUTTON_LEFT:
_left_button_down = true;
break;
case SDL_BUTTON_RIGHT:
_right_button_down = true;
_right_button_clicked = true;
break;
default: break;
}
HandleMouseEvents();
break;
case SDL_MOUSEBUTTONUP:
if (_rightclick_emulate) {
_right_button_down = false;
_left_button_down = false;
_left_button_clicked = false;
} else if (ev.button.button == SDL_BUTTON_LEFT) {
_left_button_down = false;
_left_button_clicked = false;
} else if (ev.button.button == SDL_BUTTON_RIGHT) {
_right_button_down = false;
}
HandleMouseEvents();
break;
case SDL_QUIT:
HandleExitGameRequest();
break;
case SDL_KEYDOWN: // Toggle full-screen on ALT + ENTER/F
if ((ev.key.keysym.mod & (KMOD_ALT | KMOD_GUI)) &&
(ev.key.keysym.sym == SDLK_RETURN || ev.key.keysym.sym == SDLK_f)) {
if (ev.key.repeat == 0) ToggleFullScreen(!_fullscreen);
} else {
char32_t character;
uint keycode = ConvertSdlKeyIntoMy(&ev.key.keysym, &character);
// Only handle non-text keys here. Text is handled in
// SDL_TEXTINPUT below.
if (!this->edit_box_focused ||
keycode == WKC_DELETE ||
keycode == WKC_NUM_ENTER ||
keycode == WKC_LEFT ||
keycode == WKC_RIGHT ||
keycode == WKC_UP ||
keycode == WKC_DOWN ||
keycode == WKC_HOME ||
keycode == WKC_END ||
keycode & WKC_META ||
keycode & WKC_CTRL ||
keycode & WKC_ALT ||
(keycode >= WKC_F1 && keycode <= WKC_F12) ||
!IsValidChar(character, CS_ALPHANUMERAL)) {
HandleKeypress(keycode, character);
}
}
break;
case SDL_TEXTINPUT: {
if (!this->edit_box_focused) break;
SDL_Keycode kc = SDL_GetKeyFromName(ev.text.text);
uint keycode = ConvertSdlKeycodeIntoMy(kc);
if (keycode == WKC_BACKQUOTE && FocusedWindowIsConsole()) {
char32_t character;
Utf8Decode(&character, ev.text.text);
HandleKeypress(keycode, character);
} else {
HandleTextInput(ev.text.text);
}
break;
}
case SDL_WINDOWEVENT: {
if (ev.window.event == SDL_WINDOWEVENT_EXPOSED) {
// Force a redraw of the entire screen.
this->MakeDirty(0, 0, _screen.width, _screen.height);
} else if (ev.window.event == SDL_WINDOWEVENT_SIZE_CHANGED) {
int w = std::max(ev.window.data1, 64);
int h = std::max(ev.window.data2, 64);
CreateMainSurface(w, h, w != ev.window.data1 || h != ev.window.data2);
} else if (ev.window.event == SDL_WINDOWEVENT_ENTER) {
// mouse entered the window, enable cursor
_cursor.in_window = true;
/* Ensure pointer lock will not occur. */
SDL_SetRelativeMouseMode(SDL_FALSE);
} else if (ev.window.event == SDL_WINDOWEVENT_LEAVE) {
// mouse left the window, undraw cursor
UndrawMouseCursor();
_cursor.in_window = false;
}
break;
}
}
return true;
}
static const char *InitializeSDL()
{
/* Check if the video-driver is already initialized. */
if (SDL_WasInit(SDL_INIT_VIDEO) != 0) return nullptr;
if (SDL_InitSubSystem(SDL_INIT_VIDEO) < 0) return SDL_GetError();
return nullptr;
}
const char *VideoDriver_SDL_Base::Initialize()
{
this->UpdateAutoResolution();
const char *error = InitializeSDL();
if (error != nullptr) return error;
FindResolutions();
Debug(driver, 2, "Resolution for display: {}x{}", _cur_resolution.width, _cur_resolution.height);
return nullptr;
}
const char *VideoDriver_SDL_Base::Start(const StringList &param)
{
if (BlitterFactory::GetCurrentBlitter()->GetScreenDepth() == 0) return "Only real blitters supported";
const char *error = this->Initialize();
if (error != nullptr) return error;
#ifdef SDL_HINT_MOUSE_AUTO_CAPTURE
if (GetDriverParamBool(param, "no_mouse_capture")) {
/* By default SDL captures the mouse, while a button is pressed.
* This is annoying during debugging, when OpenTTD is suspended while the button was pressed.
*/
if (!SDL_SetHint(SDL_HINT_MOUSE_AUTO_CAPTURE, "0")) return SDL_GetError();
}
#endif
this->startup_display = FindStartupDisplay(GetDriverParamInt(param, "display", -1));
if (!CreateMainSurface(_cur_resolution.width, _cur_resolution.height, false)) {
return SDL_GetError();
}
const char *dname = SDL_GetCurrentVideoDriver();
Debug(driver, 1, "SDL2: using driver '{}'", dname);
this->driver_info = this->GetName();
this->driver_info += " (";
this->driver_info += dname;
this->driver_info += ")";
MarkWholeScreenDirty();
SDL_StopTextInput();
this->edit_box_focused = false;
#ifdef __EMSCRIPTEN__
this->is_game_threaded = false;
#else
this->is_game_threaded = !GetDriverParamBool(param, "no_threads") && !GetDriverParamBool(param, "no_thread");
#endif
return nullptr;
}
void VideoDriver_SDL_Base::Stop()
{
SDL_QuitSubSystem(SDL_INIT_VIDEO);
if (SDL_WasInit(SDL_INIT_EVERYTHING) == 0) {
SDL_Quit(); // If there's nothing left, quit SDL
}
}
void VideoDriver_SDL_Base::InputLoop()
{
uint32_t mod = SDL_GetModState();
const Uint8 *keys = SDL_GetKeyboardState(nullptr);
bool old_ctrl_pressed = _ctrl_pressed;
_ctrl_pressed = !!(mod & KMOD_CTRL);
_shift_pressed = !!(mod & KMOD_SHIFT);
/* Speedup when pressing tab, except when using ALT+TAB
* to switch to another application. */
this->fast_forward_key_pressed = keys[SDL_SCANCODE_TAB] && (mod & KMOD_ALT) == 0;
/* Determine which directional keys are down. */
_dirkeys =
(keys[SDL_SCANCODE_LEFT] ? 1 : 0) |
(keys[SDL_SCANCODE_UP] ? 2 : 0) |
(keys[SDL_SCANCODE_RIGHT] ? 4 : 0) |
(keys[SDL_SCANCODE_DOWN] ? 8 : 0);
if (old_ctrl_pressed != _ctrl_pressed) HandleCtrlChanged();
}
void VideoDriver_SDL_Base::LoopOnce()
{
if (_exit_game) {
#ifdef __EMSCRIPTEN__
/* Emscripten is event-driven, and as such the main loop is inside
* the browser. So if _exit_game goes true, the main loop ends (the
* cancel call), but we still have to call the cleanup that is
* normally done at the end of the main loop for non-Emscripten.
* After that, Emscripten just halts, and the HTML shows a nice
* "bye, see you next time" message. */
extern void PostMainLoop();
PostMainLoop();
emscripten_cancel_main_loop();
emscripten_exit_pointerlock();
/* In effect, the game ends here. As emscripten_set_main_loop() caused
* the stack to be unwound, the code after MainLoop() in
* openttd_main() is never executed. */
if (_game_mode == GM_BOOTSTRAP) {
EM_ASM(if (window["openttd_bootstrap_reload"]) openttd_bootstrap_reload());
} else {
EM_ASM(if (window["openttd_exit"]) openttd_exit());
}
#endif
return;
}
this->Tick();
/* Emscripten is running an event-based mainloop; there is already some
* downtime between each iteration, so no need to sleep. */
#ifndef __EMSCRIPTEN__
this->SleepTillNextTick();
#endif
}
void VideoDriver_SDL_Base::MainLoop()
{
#ifdef __EMSCRIPTEN__
/* Run the main loop event-driven, based on RequestAnimationFrame. */
emscripten_set_main_loop_arg(&this->EmscriptenLoop, this, 0, 1);
#else
this->StartGameThread();
while (!_exit_game) {
LoopOnce();
}
this->StopGameThread();
#endif
}
bool VideoDriver_SDL_Base::ChangeResolution(int w, int h)
{
return CreateMainSurface(w, h, true);
}
bool VideoDriver_SDL_Base::ToggleFullscreen(bool fullscreen)
{
/* Remember current window size */
int w, h;
SDL_GetWindowSize(this->sdl_window, &w, &h);
if (fullscreen) {
/* Find fullscreen window size */
SDL_DisplayMode dm;
if (SDL_GetCurrentDisplayMode(SDL_GetWindowDisplayIndex(this->sdl_window), &dm) < 0) {
Debug(driver, 0, "SDL_GetCurrentDisplayMode() failed: {}", SDL_GetError());
} else {
SDL_SetWindowSize(this->sdl_window, dm.w, dm.h);
}
}
Debug(driver, 1, "SDL2: Setting {}", fullscreen ? "fullscreen" : "windowed");
int ret = SDL_SetWindowFullscreen(this->sdl_window, fullscreen ? SDL_WINDOW_FULLSCREEN : 0);
if (ret == 0) {
/* Switching resolution succeeded, set fullscreen value of window. */
_fullscreen = fullscreen;
if (!fullscreen) SDL_SetWindowSize(this->sdl_window, w, h);
} else {
Debug(driver, 0, "SDL_SetWindowFullscreen() failed: {}", SDL_GetError());
}
InvalidateWindowClassesData(WC_GAME_OPTIONS, 3);
return ret == 0;
}
bool VideoDriver_SDL_Base::AfterBlitterChange()
{
assert(BlitterFactory::GetCurrentBlitter()->GetScreenDepth() != 0);
int w, h;
SDL_GetWindowSize(this->sdl_window, &w, &h);
return CreateMainSurface(w, h, false);
}
Dimension VideoDriver_SDL_Base::GetScreenSize() const
{
SDL_DisplayMode mode;
if (SDL_GetCurrentDisplayMode(this->startup_display, &mode) != 0) return VideoDriver::GetScreenSize();
return { static_cast<uint>(mode.w), static_cast<uint>(mode.h) };
}
bool VideoDriver_SDL_Base::LockVideoBuffer()
{
if (this->buffer_locked) return false;
this->buffer_locked = true;
_screen.dst_ptr = this->GetVideoPointer();
assert(_screen.dst_ptr != nullptr);
return true;
}
void VideoDriver_SDL_Base::UnlockVideoBuffer()
{
if (_screen.dst_ptr != nullptr) {
/* Hand video buffer back to the drawing backend. */
this->ReleaseVideoPointer();
_screen.dst_ptr = nullptr;
}
this->buffer_locked = false;
}