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ClockObject::calc_frame_rate_deviation()

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This commit is contained in:
David Rose 2007-12-07 02:25:10 +00:00
parent 9dd0e3b685
commit 181f690bb8
3 changed files with 39 additions and 2 deletions
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5
panda/src/grutil/frameRateMeter.cxx
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@ -181,14 +181,15 @@ do_update(Thread *current_thread) {
_last_update = _clock_object->get_frame_time(current_thread);
double frame_rate = _clock_object->get_average_frame_rate(current_thread);
double deviation = _clock_object->calc_frame_rate_deviation(current_thread);
static const size_t buffer_size = 1024;
char buffer[buffer_size];
#ifdef WIN32_VC
// Windows doesn't define snprintf(). Hope we don't overflow.
sprintf(buffer, _text_pattern.c_str(), frame_rate);
sprintf(buffer, _text_pattern.c_str(), frame_rate, deviation);
#else
snprintf(buffer, buffer_size, _text_pattern.c_str(), frame_rate);
snprintf(buffer, buffer_size, _text_pattern.c_str(), frame_rate, deviation);
#endif
nassertv(strlen(buffer) < buffer_size);

35
panda/src/putil/clockObject.cxx
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@ -277,6 +277,41 @@ get_average_frame_rate(Thread *current_thread) const {
}
}
////////////////////////////////////////////////////////////////////
// Function: ClockObject::calc_frame_time_deviation
// Access: Published
// Description: Returns the standard deviation of the frame times of
// the frames rendered over the past
// get_average_frame_rate_interval() seconds. This
// number gives an estimate of the chugginess of the
// frame rate; if it is large, there is a large
// variation in the frame rate; if is small, all of the
// frames are consistent in length.
//
// A large value might also represent just a recent
// change in frame rate, for instance, because the
// camera has just rotated from looking at a simple
// scene to looking at a more complex scene.
////////////////////////////////////////////////////////////////////
double ClockObject::
calc_frame_rate_deviation(Thread *current_thread) const {
CDStageReader cdata(_cycler, 0, current_thread);
if (_ticks.size() <= 1) {
return 0.0;
} else {
double mean = (_ticks.back() - _ticks.front()) / (_ticks.size() - 1);
size_t i;
double sum_squares = 0.0;
for (i = 0; i < _ticks.size() - 1; ++i) {
double delta = _ticks[i + 1] - _ticks[i];
double diff = (delta - mean);
sum_squares += (diff * diff);
}
double deviation_2 = sum_squares / (_ticks.size() - 1);
return sqrt(deviation_2);
}
}
////////////////////////////////////////////////////////////////////
// Function: ClockObject::tick
// Access: Published

1
panda/src/putil/clockObject.h
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@ -108,6 +108,7 @@ PUBLISHED:
INLINE void set_average_frame_rate_interval(double time);
INLINE double get_average_frame_rate_interval() const;
double get_average_frame_rate(Thread *current_thread = Thread::get_current_thread()) const;
double calc_frame_rate_deviation(Thread *current_thread = Thread::get_current_thread()) const;
void tick(Thread *current_thread = Thread::get_current_thread());
void sync_frame_time(Thread *current_thread = Thread::get_current_thread());