OpenTTD Source: src/video/video_driver.cpp Source File

OpenTTD Source 13.2.1

video_driver.cpp
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1 /*
2 * This file is part of OpenTTD.
3 * 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.
4 * 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.
5 * 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/>.
6 */
7
10 #include "../stdafx.h"
11 #include "../core/random_func.hpp"
12 #include "../network/network.h"
13 #include "../blitter/factory.hpp"
14 #include "../debug.h"
15 #include "../driver.h"
16 #include "../fontcache.h"
17 #include "../gfx_func.h"
18 #include "../gfxinit.h"
19 #include "../progress.h"
20 #include "../thread.h"
21 #include "../window_func.h"
22 #include "video_driver.hpp"
23
24 bool _video_hw_accel;
25 bool _video_vsync;
26
27 void VideoDriver::GameLoop()
28 {
29 this->next_game_tick += this->GetGameInterval();
30
31 /* Avoid next_game_tick getting behind more and more if it cannot keep up. */
32 auto now = std::chrono::steady_clock::now();
33 if (this->next_game_tick < now - ALLOWED_DRIFT * this->GetGameInterval()) this->next_game_tick = now;
34
35 {
36 std::lock_guard<std::mutex> lock(this->game_state_mutex);
37
38 ::GameLoop();
39 }
40 }
41
42 void VideoDriver::GameThread()
43 {
44 while (!_exit_game) {
45 this->GameLoop();
46
47 auto now = std::chrono::steady_clock::now();
48 if (this->next_game_tick > now) {
49 std::this_thread::sleep_for(this->next_game_tick - now);
50 } else {
51 /* Ensure we yield this thread if drawings wants to take a lock on
52 * the game state. This is mainly because most OSes have an
53 * optimization that if you unlock/lock a mutex in the same thread
54 * quickly, it will never context switch even if there is another
55 * thread waiting to take the lock on the same mutex. */
56 std::lock_guard<std::mutex> lock(this->game_thread_wait_mutex);
57 }
58 }
59 }
60
65 void VideoDriver::GameLoopPause()
66 {
67 /* If we are not called from the game-thread, ignore this request. */
68 if (std::this_thread::get_id() != this->game_thread.get_id()) return;
69
70 this->game_state_mutex.unlock();
71
72 {
73 /* See GameThread() for more details on this lock. */
74 std::lock_guard<std::mutex> lock(this->game_thread_wait_mutex);
75 }
76
77 this->game_state_mutex.lock();
78 }
79
80 /* static */ void VideoDriver::GameThreadThunk(VideoDriver *drv)
81 {
82 drv->GameThread();
83 }
84
85 void VideoDriver::StartGameThread()
86 {
87 if (this->is_game_threaded) {
88 this->is_game_threaded = StartNewThread(&this->game_thread, "ottd:game", &VideoDriver::GameThreadThunk, this);
89 }
90
91 Debug(driver, 1, "using {}thread for game-loop", this->is_game_threaded ? "" : "no ");
92 }
93
94 void VideoDriver::StopGameThread()
95 {
96 if (!this->is_game_threaded) return;
97
98 this->game_thread.join();
99 }
100
101 void VideoDriver::Tick()
102 {
103 if (!this->is_game_threaded && std::chrono::steady_clock::now() >= this->next_game_tick) {
104 this->GameLoop();
105
106 /* For things like dedicated server, don't run a separate draw-tick. */
107 if (!this->HasGUI()) {
108 ::InputLoop();
109 ::UpdateWindows();
110 this->next_draw_tick = this->next_game_tick;
111 }
112 }
113
114 auto now = std::chrono::steady_clock::now();
115 if (this->HasGUI() && now >= this->next_draw_tick) {
116 this->next_draw_tick += this->GetDrawInterval();
117 /* Avoid next_draw_tick getting behind more and more if it cannot keep up. */
118 if (this->next_draw_tick < now - ALLOWED_DRIFT * this->GetDrawInterval()) this->next_draw_tick = now;
119
120 /* Locking video buffer can block (especially with vsync enabled), do it before taking game state lock. */
121 this->LockVideoBuffer();
122
123 {
124 /* Tell the game-thread to stop so we can have a go. */
125 std::lock_guard<std::mutex> lock_wait(this->game_thread_wait_mutex);
126 std::lock_guard<std::mutex> lock_state(this->game_state_mutex);
127
128 /* Keep the interactive randomizer a bit more random by requesting
129 * new values when-ever we can. */
130 InteractiveRandom();
131
132 this->DrainCommandQueue();
133
134 while (this->PollEvent()) {}
135 this->InputLoop();
136
137 /* Check if the fast-forward button is still pressed. */
138 if (fast_forward_key_pressed && !_networking && _game_mode != GM_MENU) {
139 ChangeGameSpeed(true);
140 this->fast_forward_via_key = true;
141 } else if (this->fast_forward_via_key) {
142 ChangeGameSpeed(false);
143 this->fast_forward_via_key = false;
144 }
145
146 ::InputLoop();
147
148 /* Prevent drawing when switching mode, as windows can be removed when they should still appear. */
149 if (_game_mode == GM_BOOTSTRAP || _switch_mode == SM_NONE || HasModalProgress()) {
150 ::UpdateWindows();
151 }
152
153 this->PopulateSystemSprites();
154 }
155
156 this->CheckPaletteAnim();
157 this->Paint();
158
159 this->UnlockVideoBuffer();
160
161 /* Wait till the first successful drawing tick before marking the driver as operational. */
162 static bool first_draw_tick = true;
163 if (first_draw_tick) {
164 first_draw_tick = false;
165 DriverFactoryBase::MarkVideoDriverOperational();
166 }
167 }
168 }
169
170 void VideoDriver::SleepTillNextTick()
171 {
172 auto next_tick = this->next_draw_tick;
173 auto now = std::chrono::steady_clock::now();
174
175 if (!this->is_game_threaded) {
176 next_tick = min(next_tick, this->next_game_tick);
177 }
178
179 if (next_tick > now) {
180 std::this_thread::sleep_for(next_tick - now);
181 }
182 }
VideoDriver::Tick
void Tick()
Give the video-driver a tick.
Definition: video_driver.cpp:101
VideoDriver
The base of all video drivers.
Definition: video_driver.hpp:35
lock
std::mutex lock
synchronization for playback status fields
Definition: win32_m.cpp:34
VideoDriver::CheckPaletteAnim
virtual void CheckPaletteAnim()
Process any pending palette animation.
Definition: video_driver.hpp:280
VideoDriver::HasGUI
virtual bool HasGUI() const
Whether the driver has a graphical user interface with the end user.
Definition: video_driver.hpp:118
VideoDriver::StartGameThread
void StartGameThread()
Start the loop for game-tick.
Definition: video_driver.cpp:85
UpdateWindows
void UpdateWindows()
Update the continuously changing contents of the windows, such as the viewports.
Definition: window.cpp:3075
VideoDriver::InputLoop
virtual void InputLoop()
Handle input logic, is CTRL pressed, should we fast-forward, etc.
Definition: video_driver.hpp:257
VideoDriver::Paint
virtual void Paint()
Paint the window.
Definition: video_driver.hpp:275
StartNewThread
bool StartNewThread(std::thread *thr, const char *name, TFn &&_Fx, TArgs &&... _Ax)
Start a new thread.
Definition: thread.h:46
_networking
bool _networking
are we in networking mode?
Definition: network.cpp:58
VideoDriver::UnlockVideoBuffer
virtual void UnlockVideoBuffer()
Unlock a previously locked video buffer.
Definition: video_driver.hpp:270
VideoDriver::GameLoopPause
void GameLoopPause()
Pause the game-loop for a bit, releasing the game-state lock.
Definition: video_driver.cpp:65
VideoDriver::StopGameThread
void StopGameThread()
Stop the loop for the game-tick.
Definition: video_driver.cpp:94
VideoDriver::PopulateSystemSprites
virtual void PopulateSystemSprites()
Populate all sprites in cache.
Definition: video_driver.hpp:103
_switch_mode
SwitchMode _switch_mode
The next mainloop command.
Definition: gfx.cpp:49
video_driver.hpp
_video_hw_accel
bool _video_hw_accel
Whether to consider hardware accelerated video drivers.
Definition: video_driver.cpp:24
VideoDriver::DrainCommandQueue
void DrainCommandQueue()
Execute all queued commands.
Definition: video_driver.hpp:328
VideoDriver::fast_forward_via_key
bool fast_forward_via_key
The fast-forward was enabled by key press.
Definition: video_driver.hpp:349
_video_vsync
bool _video_vsync
Whether we should use vsync (only if _video_hw_accel is enabled).
Definition: video_driver.cpp:25
Debug
#define Debug(name, level, format_string,...)
Ouptut a line of debugging information.
Definition: debug.h:37
VideoDriver::SleepTillNextTick
void SleepTillNextTick()
Sleep till the next tick is about to happen.
Definition: video_driver.cpp:170
VideoDriver::fast_forward_key_pressed
bool fast_forward_key_pressed
The fast-forward key is being pressed.
Definition: video_driver.hpp:348
VideoDriver::LockVideoBuffer
virtual bool LockVideoBuffer()
Make sure the video buffer is ready for drawing.
Definition: video_driver.hpp:263
HasModalProgress
static bool HasModalProgress()
Check if we are currently in a modal progress state.
Definition: progress.h:17
VideoDriver::PollEvent
virtual bool PollEvent()
Process a single system event.
Definition: video_driver.hpp:286
DriverFactoryBase::MarkVideoDriverOperational
static void MarkVideoDriverOperational()
Mark the current video driver as operational.
Definition: driver.cpp:215