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Moved responsibility for throwing in a low-pass filter up to the Vic, appropriately.

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This commit is contained in:
Thomas Harte 2016-08-21 18:13:31 -04:00
parent c783090980
commit 1541273785
3 changed files with 13 additions and 15 deletions
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6
Components/6560/6560.cpp
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@ -15,11 +15,7 @@ Speaker::Speaker() :
_control_registers{0, 0, 0, 0}, _control_registers{0, 0, 0, 0},
_shift_registers{0, 0, 0, 0}, _shift_registers{0, 0, 0, 0},
_counters{2, 1, 0, 0} // create a slight phase offset for the three channels _counters{2, 1, 0, 0} // create a slight phase offset for the three channels
{ {}
// The Vic has a 1.6Khz low-pass filter;
// TODO: this is part of the Vic-20, not part of the 6560. So relocate it.
set_high_frequency_cut_off(1600);
}
void Speaker::set_volume(uint8_t volume) void Speaker::set_volume(uint8_t volume)
{ {

1
Machines/Commodore/Vic-20/Vic20.cpp
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@ -201,6 +201,7 @@ void Machine::set_region(Commodore::Vic20::Region region)
void Machine::setup_output(float aspect_ratio) void Machine::setup_output(float aspect_ratio)
{ {
_mos6560.reset(new Vic6560()); _mos6560.reset(new Vic6560());
_mos6560->get_speaker()->set_high_frequency_cut_off(1600); // There is a 1.6Khz low-pass filter in the Vic-20.
set_region(_region); set_region(_region);
memset(_mos6560->_videoMemoryMap, 0, sizeof(_mos6560->_videoMemoryMap)); memset(_mos6560->_videoMemoryMap, 0, sizeof(_mos6560->_videoMemoryMap));

21
Outputs/Speaker.hpp
View File

@ -72,10 +72,20 @@ class Speaker {
set_needs_updated_filter_coefficients(); set_needs_updated_filter_coefficients();
} }
Speaker() : _buffer_in_progress_pointer(0), _requested_number_of_taps(0) {} /*!
Sets the cut-off frequency for a low-pass filter attached to the output of this speaker; optional.
*/
void set_high_frequency_cut_off(float high_frequency)
{
_high_frequency_cut_off = high_frequency;
set_needs_updated_filter_coefficients();
}
Speaker() : _buffer_in_progress_pointer(0), _requested_number_of_taps(0), _high_frequency_cut_off(-1.0) {}
protected: protected:
std::unique_ptr<int16_t> _buffer_in_progress; std::unique_ptr<int16_t> _buffer_in_progress;
float _high_frequency_cut_off;
int _buffer_size; int _buffer_size;
int _buffer_in_progress_pointer; int _buffer_in_progress_pointer;
int _number_of_taps, _requested_number_of_taps; int _number_of_taps, _requested_number_of_taps;
@ -109,14 +119,6 @@ class Speaker {
*/ */
template <class T> class Filter: public Speaker { template <class T> class Filter: public Speaker {
public: public:
Filter() : _high_frequency_cut_off(-1.0) {}
void set_high_frequency_cut_off(float high_frequency)
{
_high_frequency_cut_off = high_frequency;
set_needs_updated_filter_coefficients();
}
void run_for_cycles(unsigned int input_cycles) void run_for_cycles(unsigned int input_cycles)
{ {
if(_coefficients_are_dirty) update_filter_coefficients(); if(_coefficients_are_dirty) update_filter_coefficients();
@ -204,7 +206,6 @@ template <class T> class Filter: public Speaker {
std::unique_ptr<int16_t> _input_buffer; std::unique_ptr<int16_t> _input_buffer;
int _input_buffer_depth; int _input_buffer_depth;
float _high_frequency_cut_off;
void update_filter_coefficients() void update_filter_coefficients()
{ {