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DREAMWEB: Use more accurate vsync timing

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The vsync delay is 14 ms (1000 / 70), and using a loop with
a sleep of 10ms until we had passed that delay meant we were
actually waiting anytime between 14 and 23 milliseconds, which
made the game slower than it should be. This was partially
corrected by using a delay of 11 ms (800 / 70), but this was
still inacurate and too slow in average.

In addition, since the change in commit 87c8b60, it was ignoring
the time spent in the game loop, which on slow devices is not
negligeable, and this has been fixed as well.

Finally also change the fast speed from 20 to 4. In commit
87c8b60 the delay was changed from macroseconds to milliseconds,
and any speed above 14 would then result in a delay of 0 due to
the integer division. We have the turbo mode for that, so it
seems to make sense to make the fast mode a bit slower rather
than having two modes that do the same thing.
This commit is contained in:
Thierry Crozat 2020-05-02 23:55:52 +01:00
parent 8038305660
commit 75f8cfac56
2 changed files with 17 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
engines/dreamweb/dreamweb.cpp
View File

@ -49,6 +49,7 @@ DreamWebEngine::DreamWebEngine(OSystem *syst, const DreamWebGameDescription *gam
DebugMan.addDebugChannel(kDebugAnimation, "Animation", "Animation Debug Flag");
DebugMan.addDebugChannel(kDebugSaveLoad, "SaveLoad", "Track Save/Load Function");
_vSyncPrevTick = 0;
_sound = 0;
_speed = 1;
_turbo = false;
@ -272,22 +273,25 @@ DreamWebEngine::~DreamWebEngine() {
delete _sound;
}
void DreamWebEngine::waitForVSync() {
const uint32 previousTicks = _system->getMillis();
// Originally, this was an interval for a thread that was
// called every 1000000 / 70 nanoseconds. It has been
// adjusted to be a delay instead.
const uint32 delay = 800 / 70 / _speed;
void DreamWebEngine::pauseEngineIntern(bool pause) {
Engine::pauseEngineIntern(pause);
if (!pause)
_vSyncPrevTick = _system->getMillis();
}
void DreamWebEngine::waitForVSync() {
if (isPaused())
return;
processEvents();
while (!_turbo && _system->getMillis() - previousTicks < delay) {
processEvents(false);
_system->delayMillis(10);
if (!_turbo) {
const uint32 delay = 1000 / 70 / _speed;
uint32 elapsed = _system->getMillis() - _vSyncPrevTick;
if (elapsed < delay)
_system->delayMillis(delay - elapsed);
}
_vSyncPrevTick = _system->getMillis();
doShake();
doFade();
@ -320,7 +324,7 @@ void DreamWebEngine::processEvents(bool processSoundEvents) {
switch (event.kbd.keycode) {
case Common::KEYCODE_f:
setSpeed(_speed != 20? 20: 1);
setSpeed(_speed != 4? 4: 1);
break;
case Common::KEYCODE_g:
@ -399,6 +403,7 @@ Common::Error DreamWebEngine::run() {
_brightPalette = ConfMan.getBool("bright_palette");
_copyProtection = ConfMan.getBool("copy_protection");
_vSyncPrevTick = _system->getMillis();
dreamweb();
dreamwebFinalize();
_quitRequested = false;

2
engines/dreamweb/dreamweb.h
View File

@ -101,11 +101,13 @@ class DreamWebSound;
class DreamWebEngine : public Engine {
private:
DreamWebSound *_sound;
uint32 _vSyncPrevTick;
protected:
// Engine APIs
Common::Error run() override;
bool hasFeature(EngineFeature f) const override;
void pauseEngineIntern(bool pause) override;
public:
DreamWebEngine(OSystem *syst, const DreamWebGameDescription *gameDesc);