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Fixed end of sync time calculation and ensured the pretend capacitor is emptied by the decision to retrace and doesn't refill during retrace.

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This commit is contained in:
Thomas Harte 2015-08-05 20:29:20 -04:00
parent 04c2640b15
commit 84d1c2e47d
1 changed files with 10 additions and 10 deletions
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20
Outputs/CRT.cpp
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@ -20,7 +20,7 @@ static const uint32_t kCRTFixedPointOffset = 0x08000000;
void CRT::set_new_timing(int cycles_per_line, int height_of_display)
{
const int syncCapacityLineChargeThreshold = 5;
const int syncCapacityLineChargeThreshold = 3;
const int millisecondsHorizontalRetraceTime = 10; // source: Dictionary of Video and Television Technology, p. 234
const int scanlinesVerticalRetraceTime = 7; // source: ibid
@ -28,7 +28,7 @@ void CRT::set_new_timing(int cycles_per_line, int height_of_display)
height_of_display += (height_of_display / 20); // this is the overrun area we'll use to
// store fundamental display configuration properties
_height_of_display = height_of_display + 10;
_height_of_display = height_of_display;
_cycles_per_line = cycles_per_line * _time_multiplier;
// generate timing values implied by the given arbuments
@ -103,12 +103,11 @@ CRT::SyncEvent CRT::get_next_vertical_sync_event(bool vsync_is_requested, int cy
// will an acceptable vertical sync be triggered?
if (vsync_is_requested && !_is_in_vsync) {
if (_sync_capacitor_charge_level >= _sync_capacitor_charge_threshold) {// && _rasterPosition.y >= (kCRTFixedPointRange * 7) >> 3) {
// printf("%d v %d\n", _sync_capacitor_charge_level, _sync_capacitor_charge_threshold);
proposedSyncTime = 0;
proposedEvent = SyncEvent::StartVSync;
_did_detect_vsync = true;
}
if (_sync_capacitor_charge_level >= _sync_capacitor_charge_threshold) {// && _rasterPosition.y >= (kCRTFixedPointRange * 7) >> 3) {
proposedSyncTime = 0;
proposedEvent = SyncEvent::StartVSync;
_did_detect_vsync = true;
}
}
// have we overrun the maximum permitted number of horizontal syncs for this frame?
@ -120,7 +119,7 @@ CRT::SyncEvent CRT::get_next_vertical_sync_event(bool vsync_is_requested, int cy
proposedEvent = SyncEvent::StartVSync;
}*/
} else {
int time_until_start_of_frame = _rasterPosition.y / _scanSpeed[kRetraceYMask].y;
uint32_t time_until_start_of_frame = _rasterPosition.y / (uint32_t)(-_scanSpeed[kRetraceYMask].y);
if(time_until_start_of_frame < proposedSyncTime) {
proposedSyncTime = time_until_start_of_frame;
@ -252,7 +251,7 @@ void CRT::advance_cycles(int number_of_cycles, bool hsync_requested, bool vsync_
_horizontal_counter += next_run_length;
// either charge or deplete the vertical retrace capacitor (making sure it stops at 0)
if (vsync_charging)
if (vsync_charging && !_is_in_vsync)
_sync_capacitor_charge_level += next_run_length;
else
_sync_capacitor_charge_level = std::max(_sync_capacitor_charge_level - next_run_length, 0);
@ -291,6 +290,7 @@ void CRT::advance_cycles(int number_of_cycles, bool hsync_requested, bool vsync_
// load the retrace counter with the amount of time it'll take to retrace
case SyncEvent::StartVSync:
_is_in_vsync = true;
_sync_capacitor_charge_level = 0;
break;
// end of vertical sync: tell the delegate that we finished vertical sync,