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Made an attempt to simplify in-shader phase calculation, now that output position is a direct multiple of phase.

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This commit is contained in:
Thomas Harte 2017-01-11 08:18:00 -05:00
parent 4c3669f210
commit d0a93409e6
3 changed files with 7 additions and 9 deletions
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12
Outputs/CRT/CRT.cpp
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@ -112,7 +112,6 @@ Flywheel::SyncEvent CRT::get_next_horizontal_sync_event(bool hsync_is_requested,
#define source_output_position_x2() (*(uint16_t *)&next_run[SourceVertexOffsetOfEnds + 2])
#define source_phase() next_run[SourceVertexOffsetOfPhaseTimeAndAmplitude + 0]
#define source_amplitude() next_run[SourceVertexOffsetOfPhaseTimeAndAmplitude + 2]
#define source_phase_time() next_run[SourceVertexOffsetOfPhaseTimeAndAmplitude + 1]
void CRT::advance_cycles(unsigned int number_of_cycles, bool hsync_requested, bool vsync_requested, const bool vsync_charging, const Scan::Type type)
{
@ -147,9 +146,8 @@ void CRT::advance_cycles(unsigned int number_of_cycles, bool hsync_requested, bo
{
// output_y and texture locations will be written later; we won't necessarily know what it is outside of the locked region
source_output_position_x1() = (uint16_t)horizontal_flywheel_->get_current_output_position();
source_phase() = 31 + colour_burst_phase_ & ~63; // phase is rounded to the nearest 1/4 of a cycle
source_phase() = colour_burst_phase_;
source_amplitude() = colour_burst_amplitude_;
source_phase_time() = (uint8_t)colour_burst_time_; // assumption: burst was within the first 1/16 of the line
}
// decrement the number of cycles left to run for and increment the
@ -288,9 +286,11 @@ void CRT::output_scan(const Scan *const scan)
{
if(horizontal_flywheel_->get_current_time() < (horizontal_flywheel_->get_standard_period() * 12) >> 6)
{
colour_burst_time_ = (uint16_t)horizontal_flywheel_->get_current_time();
colour_burst_phase_ = scan->phase;
unsigned 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;
colour_burst_phase_ &= ~63;
}
}
@ -346,7 +346,7 @@ void CRT::output_default_colour_burst(unsigned int number_of_cycles)
Scan scan {
.type = Scan::Type::ColourBurst,
.number_of_cycles = number_of_cycles,
.phase = (uint8_t)((phase_numerator_ * 255) / phase_denominator_ + (is_alernate_line_ ? 128 : 0)),
.phase = (uint8_t)((phase_numerator_ * 256) / phase_denominator_ + (is_alernate_line_ ? 128 : 0)),
.amplitude = 32
};
output_scan(&scan);

1
Outputs/CRT/CRT.hpp
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@ -60,7 +60,6 @@ class CRT {
void output_scan(const Scan *scan);
uint8_t colour_burst_phase_, colour_burst_amplitude_;
uint16_t colour_burst_time_;
bool is_writing_composite_run_;
unsigned int phase_denominator_, phase_numerator_, colour_cycle_numerator_;

3
Outputs/CRT/Internals/Shaders/IntermediateShader.cpp
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@ -93,8 +93,7 @@ std::unique_ptr<IntermediateShader> IntermediateShader::make_shader(const char *
// setup phaseAndAmplitudeVarying.x as colour burst subcarrier phase, in radians;
// setup phaseAndAmplitudeVarying.x as colour burst amplitude
"phaseAndAmplitudeVarying.x = (extendedOutputPosition.x - phaseTimeAndAmplitude.y*widthScalers[1]) / 4.0 + phaseTimeAndAmplitude.x / 255.0;"
"phaseAndAmplitudeVarying.x *= 2.0 * 3.141592654;"
"phaseAndAmplitudeVarying.x = (extendedOutputPosition.x + (phaseTimeAndAmplitude.x / 64.0)) * 0.5 * 3.141592654;"
"phaseAndAmplitudeVarying.y = 0.33;" // TODO: reinstate connection with (phaseTimeAndAmplitude.y/256.0)
// determine output position by scaling the output position according to the texture size