diff options
Diffstat (limited to 'ym2612.c')
| -rw-r--r-- | ym2612.c | 53 |
1 files changed, 38 insertions, 15 deletions
@@ -116,18 +116,20 @@ void ym_finalize_log() } log_context = NULL; } -#define BUFFER_INC_RES 1000000000UL +#define BUFFER_INC_RES 0x40000000UL void ym_adjust_master_clock(ym2612_context * context, uint32_t master_clock) { uint64_t old_inc = context->buffer_inc; - context->buffer_inc = ((BUFFER_INC_RES * (uint64_t)context->sample_rate) / (uint64_t)master_clock) * (uint64_t)context->clock_inc; + context->buffer_inc = ((BUFFER_INC_RES * (uint64_t)context->sample_rate) / (uint64_t)master_clock) * (uint64_t)context->clock_inc * NUM_OPERATORS; } #ifdef __ANDROID__ #define log2(x) (log(x)/log(2)) #endif +#define LOWPASS_CUTOFF 3390 + void ym_init(ym2612_context * context, uint32_t sample_rate, uint32_t master_clock, uint32_t clock_div, uint32_t sample_limit, uint32_t options) { static uint8_t registered_finalize; @@ -138,6 +140,11 @@ void ym_init(ym2612_context * context, uint32_t sample_rate, uint32_t master_clo context->sample_rate = sample_rate; context->clock_inc = clock_div * 6; ym_adjust_master_clock(context, master_clock); + + double rc = (1.0 / (double)LOWPASS_CUTOFF) / (2.0 * M_PI); + double dt = 1.0 / ((double)master_clock / (double)(context->clock_inc * NUM_OPERATORS)); + double alpha = dt / (dt + rc); + context->lowpass_alpha = (int32_t)(((double)0x10000) * alpha); context->sample_limit = sample_limit*2; context->write_cycle = CYCLE_NEVER; @@ -478,14 +485,11 @@ void ym_run(ym2612_context * context, uint32_t to_cycle) //puts("operator update done"); } context->current_op++; - context->buffer_fraction += context->buffer_inc; if (context->current_op == NUM_OPERATORS) { context->current_op = 0; - } - if (context->buffer_fraction > BUFFER_INC_RES) { - context->buffer_fraction -= BUFFER_INC_RES; - context->audio_buffer[context->buffer_pos] = 0; - context->audio_buffer[context->buffer_pos + 1] = 0; + + context->buffer_fraction += context->buffer_inc; + int16_t left = 0, right = 0; for (int i = 0; i < NUM_CHANNELS; i++) { int16_t value = context->channels[i].output; if (value > 0x1FE0) { @@ -498,23 +502,42 @@ void ym_run(ym2612_context * context, uint32_t to_cycle) value |= 0xC000; } } - if (context->channels[i].logfile) { + if (context->channels[i].logfile && context->buffer_fraction > BUFFER_INC_RES) { fwrite(&value, sizeof(value), 1, context->channels[i].logfile); } if (context->channels[i].lr & 0x80) { - context->audio_buffer[context->buffer_pos] += (value * YM_VOLUME_MULTIPLIER) / YM_VOLUME_DIVIDER; + left += (value * YM_VOLUME_MULTIPLIER) / YM_VOLUME_DIVIDER; } if (context->channels[i].lr & 0x40) { - context->audio_buffer[context->buffer_pos+1] += (value * YM_VOLUME_MULTIPLIER) / YM_VOLUME_DIVIDER; + right += (value * YM_VOLUME_MULTIPLIER) / YM_VOLUME_DIVIDER; } } - context->buffer_pos += 2; - if (context->buffer_pos == context->sample_limit) { - if (!headless) { - render_wait_ym(context); + int32_t tmp = left * context->lowpass_alpha + context->last_left * (0x10000 - context->lowpass_alpha); + left = tmp >> 16; + tmp = right * context->lowpass_alpha + context->last_right * (0x10000 - context->lowpass_alpha); + right = tmp >> 16; + if (context->buffer_fraction > BUFFER_INC_RES) { + context->buffer_fraction -= BUFFER_INC_RES; + + int64_t tmp = context->last_left * ((context->buffer_fraction << 16) / context->buffer_inc); + tmp += left * (0x10000 - ((context->buffer_fraction << 16) / context->buffer_inc)); + context->audio_buffer[context->buffer_pos] = tmp >> 16; + + tmp = context->last_right * ((context->buffer_fraction << 16) / context->buffer_inc); + tmp += right * (0x10000 - ((context->buffer_fraction << 16) / context->buffer_inc)); + context->audio_buffer[context->buffer_pos+1] = tmp >> 16; + + context->buffer_pos += 2; + if (context->buffer_pos == context->sample_limit) { + if (!headless) { + render_wait_ym(context); + } } } + context->last_left = left; + context->last_right = right; } + } if (context->current_cycle >= context->write_cycle + (context->busy_cycles * context->clock_inc / 6)) { context->status &= 0x7F; |