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

OpenTTD Source 12.2

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 "../fontcache.h"
16 #include "../gfx_func.h"
17 #include "../gfxinit.h"
18 #include "../progress.h"
19 #include "../thread.h"
20 #include "../window_func.h"
21 #include "video_driver.hpp"
22
23 bool _video_hw_accel;
24 bool _video_vsync;
25
26 void VideoDriver::GameLoop()
27 {
28 this->next_game_tick += this->GetGameInterval();
29
30 /* Avoid next_game_tick getting behind more and more if it cannot keep up. */
31 auto now = std::chrono::steady_clock::now();
32 if (this->next_game_tick < now - ALLOWED_DRIFT * this->GetGameInterval()) this->next_game_tick = now;
33
34 {
35 std::lock_guard<std::mutex> lock(this->game_state_mutex);
36
37 ::GameLoop();
38 }
39 }
40
41 void VideoDriver::GameThread()
42 {
43 while (!_exit_game) {
44 this->GameLoop();
45
46 auto now = std::chrono::steady_clock::now();
47 if (this->next_game_tick > now) {
48 std::this_thread::sleep_for(this->next_game_tick - now);
49 } else {
50 /* Ensure we yield this thread if drawings wants to take a lock on
51 * the game state. This is mainly because most OSes have an
52 * optimization that if you unlock/lock a mutex in the same thread
53 * quickly, it will never context switch even if there is another
54 * thread waiting to take the lock on the same mutex. */
55 std::lock_guard<std::mutex> lock(this->game_thread_wait_mutex);
56 }
57 }
58 }
59
64 void VideoDriver::GameLoopPause()
65 {
66 /* If we are not called from the game-thread, ignore this request. */
67 if (std::this_thread::get_id() != this->game_thread.get_id()) return;
68
69 this->game_state_mutex.unlock();
70
71 {
72 /* See GameThread() for more details on this lock. */
73 std::lock_guard<std::mutex> lock(this->game_thread_wait_mutex);
74 }
75
76 this->game_state_mutex.lock();
77 }
78
79 /* static */ void VideoDriver::GameThreadThunk(VideoDriver *drv)
80 {
81 drv->GameThread();
82 }
83
84 void VideoDriver::StartGameThread()
85 {
86 if (this->is_game_threaded) {
87 this->is_game_threaded = StartNewThread(&this->game_thread, "ottd:game", &VideoDriver::GameThreadThunk, this);
88 }
89
90 Debug(driver, 1, "using {}thread for game-loop", this->is_game_threaded ? "" : "no ");
91 }
92
93 void VideoDriver::StopGameThread()
94 {
95 if (!this->is_game_threaded) return;
96
97 this->game_thread.join();
98 }
99
100 void VideoDriver::Tick()
101 {
102 if (!this->is_game_threaded && std::chrono::steady_clock::now() >= this->next_game_tick) {
103 this->GameLoop();
104
105 /* For things like dedicated server, don't run a separate draw-tick. */
106 if (!this->HasGUI()) {
107 ::InputLoop();
108 ::UpdateWindows();
109 this->next_draw_tick = this->next_game_tick;
110 }
111 }
112
113 auto now = std::chrono::steady_clock::now();
114 if (this->HasGUI() && now >= this->next_draw_tick) {
115 this->next_draw_tick += this->GetDrawInterval();
116 /* Avoid next_draw_tick getting behind more and more if it cannot keep up. */
117 if (this->next_draw_tick < now - ALLOWED_DRIFT * this->GetDrawInterval()) this->next_draw_tick = now;
118
119 /* Locking video buffer can block (especially with vsync enabled), do it before taking game state lock. */
120 this->LockVideoBuffer();
121
122 {
123 /* Tell the game-thread to stop so we can have a go. */
124 std::lock_guard<std::mutex> lock_wait(this->game_thread_wait_mutex);
125 std::lock_guard<std::mutex> lock_state(this->game_state_mutex);
126
127 /* Keep the interactive randomizer a bit more random by requesting
128 * new values when-ever we can. */
129 InteractiveRandom();
130
131 this->DrainCommandQueue();
132
133 while (this->PollEvent()) {}
134 this->InputLoop();
135
136 /* Check if the fast-forward button is still pressed. */
137 if (fast_forward_key_pressed && !_networking && _game_mode != GM_MENU) {
138 ChangeGameSpeed(true);
139 this->fast_forward_via_key = true;
140 } else if (this->fast_forward_via_key) {
141 ChangeGameSpeed(false);
142 this->fast_forward_via_key = false;
143 }
144
145 ::InputLoop();
146
147 /* Prevent drawing when switching mode, as windows can be removed when they should still appear. */
148 if (_game_mode == GM_BOOTSTRAP || _switch_mode == SM_NONE || HasModalProgress()) {
149 ::UpdateWindows();
150 }
151
152 this->PopulateSystemSprites();
153 }
154
155 this->CheckPaletteAnim();
156 this->Paint();
157
158 this->UnlockVideoBuffer();
159 }
160 }
161
162 void VideoDriver::SleepTillNextTick()
163 {
164 auto next_tick = this->next_draw_tick;
165 auto now = std::chrono::steady_clock::now();
166
167 if (!this->is_game_threaded) {
168 next_tick = min(next_tick, this->next_game_tick);
169 }
170
171 if (next_tick > now) {
172 std::this_thread::sleep_for(next_tick - now);
173 }
174 }
VideoDriver::Tick
void Tick()
Give the video-driver a tick.
Definition: video_driver.cpp:100
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:277
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:84
UpdateWindows
void UpdateWindows()
Update the continuously changing contents of the windows, such as the viewports.
Definition: window.cpp:3058
VideoDriver::InputLoop
virtual void InputLoop()
Handle input logic, is CTRL pressed, should we fast-forward, etc.
Definition: video_driver.hpp:254
VideoDriver::Paint
virtual void Paint()
Paint the window.
Definition: video_driver.hpp:272
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:57
VideoDriver::UnlockVideoBuffer
virtual void UnlockVideoBuffer()
Unlock a previously locked video buffer.
Definition: video_driver.hpp:267
VideoDriver::GameLoopPause
void GameLoopPause()
Pause the game-loop for a bit, releasing the game-state lock.
Definition: video_driver.cpp:64
VideoDriver::StopGameThread
void StopGameThread()
Stop the loop for the game-tick.
Definition: video_driver.cpp:93
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:47
video_driver.hpp
_video_hw_accel
bool _video_hw_accel
Whether to consider hardware accelerated video drivers.
Definition: video_driver.cpp:23
VideoDriver::DrainCommandQueue
void DrainCommandQueue()
Execute all queued commands.
Definition: video_driver.hpp:325
VideoDriver::fast_forward_via_key
bool fast_forward_via_key
The fast-forward was enabled by key press.
Definition: video_driver.hpp:346
_video_vsync
bool _video_vsync
Whether we should use vsync (only if _video_hw_accel is enabled).
Definition: video_driver.cpp:24
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:162
VideoDriver::fast_forward_key_pressed
bool fast_forward_key_pressed
The fast-forward key is being pressed.
Definition: video_driver.hpp:345
VideoDriver::LockVideoBuffer
virtual bool LockVideoBuffer()
Make sure the video buffer is ready for drawing.
Definition: video_driver.hpp:260
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:283