#include "nes_vrc7_apu.h" #include "blargg_source.h" int const period = 36; // NES CPU clocks per FM clock void Vrc7_init( struct Nes_Vrc7_Apu* this ) { Synth_init( &this->synth ); OPLL_new ( &this->opll, 3579545, 3579545 / 72 ); OPLL_reset_patch( &this->opll, OPLL_VRC7_TONE ); this->osc.output = 0; this->osc.last_amp = 0; this->mask = 0; Vrc7_volume( this, (int)FP_ONE_VOLUME ); Vrc7_reset( this ); } void Vrc7_reset( struct Nes_Vrc7_Apu* this ) { this->addr = 0; this->next_time = 0; this->osc.last_amp = 0; OPLL_reset (&this->opll); OPLL_setMask(&this->opll, this->mask); } void Vrc7_set_rate( struct Nes_Vrc7_Apu* this, double r ) { OPLL_set_quality( &this->opll, r < 44100 ? 0 : 1 ); OPLL_set_rate( &this->opll, (e_uint32)r ); } void Vrc7_write_reg( struct Nes_Vrc7_Apu* this, int data ) { this->addr = data; } void Vrc7_run_until( struct Nes_Vrc7_Apu* this, blip_time_t end_time ); void Vrc7_write_data( struct Nes_Vrc7_Apu* this, blip_time_t time, int data ) { if ( time > this->next_time ) Vrc7_run_until( this, time ); OPLL_writeIO( &this->opll, 0, this->addr ); OPLL_writeIO( &this->opll, 1, data ); } void Vrc7_end_frame( struct Nes_Vrc7_Apu* this, blip_time_t time ) { if ( time > this->next_time ) Vrc7_run_until( this, time ); this->next_time -= time; assert( this->next_time >= 0 ); if ( this->osc.output ) Blip_set_modified( this->osc.output ); } void Vrc7_run_until( struct Nes_Vrc7_Apu* this, blip_time_t end_time ) { require( end_time > this->next_time ); blip_time_t time = this->next_time; OPLL* opll = &this->opll; // cache struct Blip_Buffer* const output = this-> osc.output; if ( output ) { do { int amp = OPLL_calc( opll ) << 1; int delta = amp - this->osc.last_amp; if ( delta ) { this->osc.last_amp = amp; Synth_offset_inline( &this->synth, time, delta, output ); } time += period; } while ( time < end_time ); } this->next_time = time; }