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Implements get_scan_status, but for scale being incorrect.

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This commit is contained in:
Thomas Harte 2020-01-20 21:58:34 -05:00
parent d97a073d1b
commit 82e5def7c4
2 changed files with 23 additions and 1 deletions
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6
Outputs/CRT/CRT.cpp
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@ -469,5 +469,9 @@ Outputs::Display::Rect CRT::get_rect_for_area(int first_line_after_sync, int num
}
Outputs::Display::ScanStatus CRT::get_scan_status() const {
return Outputs::Display::ScanStatus();
Outputs::Display::ScanStatus status;
status.field_duration = vertical_flywheel_->get_locked_period();
status.field_duration_gradient = vertical_flywheel_->get_last_period_adjustment();
status.current_position = float(vertical_flywheel_->get_current_output_position()) / float(vertical_flywheel_->get_locked_period());
return status;
}

18
Outputs/CRT/Internals/Flywheel.hpp
View File

@ -63,6 +63,7 @@ struct Flywheel {
inline SyncEvent get_next_event_in_period(bool sync_is_requested, int cycles_to_run_for, int *cycles_advanced) {
// If sync is signalled _now_, consider adjusting expected_next_sync_.
if(sync_is_requested) {
const auto last_sync = expected_next_sync_;
if(counter_ < sync_error_window_ || counter_ > expected_next_sync_ - sync_error_window_) {
const int time_now = (counter_ < sync_error_window_) ? expected_next_sync_ + counter_ : counter_;
expected_next_sync_ = (3*expected_next_sync_ + time_now) >> 2;
@ -75,6 +76,7 @@ struct Flywheel {
expected_next_sync_ = (3*expected_next_sync_ + standard_period_ - sync_error_window_) >> 2;
}
}
last_adjustment_ = expected_next_sync_ - last_sync;
}
SyncEvent proposed_event = SyncEvent::None;
@ -165,6 +167,20 @@ struct Flywheel {
return standard_period_;
}
/*!
@returns the actual current period for a complete scan (including retrace).
*/
inline int get_locked_period() {
return expected_next_sync_;
}
/*!
@returns the amount by which the @c locked_period was adjusted, the last time that an adjustment was applied.
*/
inline int get_last_period_adjustment() {
return last_adjustment_;
}
/*!
@returns the number of synchronisation events that have seemed surprising since the last time this method was called;
a low number indicates good synchronisation.
@ -195,6 +211,8 @@ struct Flywheel {
int number_of_surprises_ = 0; // a count of the surprising syncs
int last_adjustment_ = 0; // The amount by which
/*
Implementation notes: