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/*
* 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 video_driver.cpp Common code between video driver implementations. */
#include "../stdafx.h"
#include "../core/random_func.hpp"
#include "../network/network.h"
#include "../blitter/factory.hpp"
#include "../debug.h"
#include "../fontcache.h"
#include "../gfx_func.h"
#include "../gfxinit.h"
#include "../progress.h"
#include "../thread.h"
#include "../window_func.h"
#include "video_driver.hpp"
bool _video_hw_accel; ///< Whether to consider hardware accelerated video drivers.
bool _video_vsync; ///< Whether we should use vsync (only if _video_hw_accel is enabled).
void VideoDriver::GameLoop()
{
this->next_game_tick += this->GetGameInterval();
/* Avoid next_game_tick getting behind more and more if it cannot keep up. */
auto now = std::chrono::steady_clock::now();
if (this->next_game_tick < now - ALLOWED_DRIFT * this->GetGameInterval()) this->next_game_tick = now;
{
std::lock_guard<std::mutex> lock(this->game_state_mutex);
::GameLoop();
}
}
void VideoDriver::GameThread()
{
while (!_exit_game) {
this->GameLoop();
auto now = std::chrono::steady_clock::now();
if (this->next_game_tick > now) {
std::this_thread::sleep_for(this->next_game_tick - now);
} else {
/* Ensure we yield this thread if drawings wants to take a lock on
* the game state. This is mainly because most OSes have an
* optimization that if you unlock/lock a mutex in the same thread
* quickly, it will never context switch even if there is another
* thread waiting to take the lock on the same mutex. */
std::lock_guard<std::mutex> lock(this->game_thread_wait_mutex);
}
}
}
/**
* Pause the game-loop for a bit, releasing the game-state lock. This allows,
* if the draw-tick requested this, the drawing to happen.
*/
void VideoDriver::GameLoopPause()
{
/* If we are not called from the game-thread, ignore this request. */
if (std::this_thread::get_id() != this->game_thread.get_id()) return;
this->game_state_mutex.unlock();
{
/* See GameThread() for more details on this lock. */
std::lock_guard<std::mutex> lock(this->game_thread_wait_mutex);
}
this->game_state_mutex.lock();
}
/* static */ void VideoDriver::GameThreadThunk(VideoDriver *drv)
{
drv->GameThread();
}
void VideoDriver::StartGameThread()
{
if (this->is_game_threaded) {
this->is_game_threaded = StartNewThread(&this->game_thread, "ottd:game", &VideoDriver::GameThreadThunk, this);
}
Debug(driver, 1, "using {}thread for game-loop", this->is_game_threaded ? "" : "no ");
}
void VideoDriver::StopGameThread()
{
if (!this->is_game_threaded) return;
this->game_thread.join();
}
void VideoDriver::Tick()
{
if (!this->is_game_threaded && std::chrono::steady_clock::now() >= this->next_game_tick) {
this->GameLoop();
/* For things like dedicated server, don't run a separate draw-tick. */
if (!this->HasGUI()) {
::InputLoop();
::UpdateWindows();
this->next_draw_tick = this->next_game_tick;
}
}
auto now = std::chrono::steady_clock::now();
if (this->HasGUI() && now >= this->next_draw_tick) {
this->next_draw_tick += this->GetDrawInterval();
/* Avoid next_draw_tick getting behind more and more if it cannot keep up. */
if (this->next_draw_tick < now - ALLOWED_DRIFT * this->GetDrawInterval()) this->next_draw_tick = now;
/* Locking video buffer can block (especially with vsync enabled), do it before taking game state lock. */
this->LockVideoBuffer();
{
/* Tell the game-thread to stop so we can have a go. */
std::lock_guard<std::mutex> lock_wait(this->game_thread_wait_mutex);
std::lock_guard<std::mutex> lock_state(this->game_state_mutex);
/* Keep the interactive randomizer a bit more random by requesting
* new values when-ever we can. */
InteractiveRandom();
this->DrainCommandQueue();
while (this->PollEvent()) {}
this->InputLoop();
/* Check if the fast-forward button is still pressed. */
if (fast_forward_key_pressed && !_networking && _game_mode != GM_MENU) {
ChangeGameSpeed(true);
this->fast_forward_via_key = true;
} else if (this->fast_forward_via_key) {
ChangeGameSpeed(false);
this->fast_forward_via_key = false;
}
::InputLoop();
/* Prevent drawing when switching mode, as windows can be removed when they should still appear. */
if (_game_mode == GM_BOOTSTRAP || _switch_mode == SM_NONE || HasModalProgress()) {
::UpdateWindows();
}
this->PopulateSystemSprites();
}
this->CheckPaletteAnim();
this->Paint();
this->UnlockVideoBuffer();
}
}
void VideoDriver::SleepTillNextTick()
{
auto next_tick = this->next_draw_tick;
auto now = std::chrono::steady_clock::now();
if (!this->is_game_threaded) {
next_tick = min(next_tick, this->next_game_tick);
}
if (next_tick > now) {
std::this_thread::sleep_for(next_tick - now);
}
}
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