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Reintroduces colour phase acquisition from the colour burst.

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This commit is contained in:
Thomas Harte 2018-11-04 21:57:46 -05:00
parent eb28095041
commit 1effb97b74
2 changed files with 11 additions and 7 deletions
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16
Outputs/CRT/CRT.cpp
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@ -185,7 +185,6 @@ void CRT::advance_cycles(int number_of_cycles, bool hsync_requested, bool vsync_
scan_target_->announce(Outputs::Display::ScanTarget::Event::HorizontalRetrace);
is_alernate_line_ ^= phase_alternates_;
colour_burst_amplitude_ = 0;
phase_numerator_ = 0;
}
// Also announce if this is vertical retrace.
@ -216,12 +215,16 @@ void CRT::output_scan(const Scan *const scan) {
// simplified colour burst logic: if it's within the back porch we'll take it
if(scan->type == Scan::Type::ColourBurst) {
if(!colour_burst_amplitude_ && horizontal_flywheel_->get_current_time() < (horizontal_flywheel_->get_standard_period() * 12) >> 6) {
// int position_phase = (horizontal_flywheel_->get_current_time() * colour_cycle_numerator_ * 256) / phase_denominator_;
// colour_burst_phase_ = (position_phase + scan->phase) & 255;
colour_burst_amplitude_ = scan->amplitude;
// Load phase_numerator_ as a fixed-point quantity in the range [0, 255].
phase_numerator_ = scan->phase;
if(colour_burst_phase_adjustment_ != 0xff)
phase_numerator_ = (phase_numerator_ & ~63) + colour_burst_phase_adjustment_;
// if(colour_burst_phase_adjustment_ != 0xff)
// colour_burst_phase_ = (colour_burst_phase_ & ~63) + colour_burst_phase_adjustment_;
// Multiply the phase_numerator_ up to be to the proper scale.
phase_numerator_ = (phase_numerator_ * phase_denominator_) >> 8;
// Crib the colour burst amplitude.
colour_burst_amplitude_ = scan->amplitude;
}
}
// TODO: inspect raw data for potential colour burst if required; the DPLL and some zero crossing logic
@ -313,6 +316,7 @@ void CRT::output_colour_burst(int number_of_cycles, uint8_t phase, uint8_t ampli
}
void CRT::output_default_colour_burst(int number_of_cycles) {
// TODO: avoid applying a rounding error here?
output_colour_burst(number_of_cycles, static_cast<uint8_t>((phase_numerator_ * 256) / phase_denominator_));
}

2
Outputs/CRT/CRT.hpp
View File

@ -50,7 +50,7 @@ class CRT {
int16_t colour_burst_angle_ = 0;
uint8_t colour_burst_amplitude_ = 30;
int colour_burst_phase_adjustment_ = 0;
int colour_burst_phase_adjustment_ = 0xff;
bool is_writing_composite_run_ = false;
int64_t phase_denominator_ = 1;