diff options
Diffstat (limited to 'source')
| -rw-r--r-- | source/soundux.c | 126 | ||||
| -rw-r--r-- | source/soundux.h | 1 |
2 files changed, 114 insertions, 13 deletions
diff --git a/source/soundux.c b/source/soundux.c index 66b546b..1c59ff0 100644 --- a/source/soundux.c +++ b/source/soundux.c @@ -8,25 +8,18 @@ #include <retro_inline.h> -#define CLIP16(v) \ -if ((v) < -32768) \ - (v) = -32768; \ -else \ -if ((v) > 32767) \ - (v) = 32767 - -#define CLIP8(v) \ -if ((v) < -128) \ - (v) = -128; \ -else if ((v) > 127) \ - (v) = 127 - #include "snes9x.h" #include "soundux.h" #include "apu.h" #include "memmap.h" #include "cpuexec.h" +#define CLIP16(v) \ +(v) = (((v) <= -32768) ? -32768 : (((v) >= 32767) ? 32767 : (v))) + +#define CLIP8(v) \ +(v) = (((v) <= -128) ? -128 : (((v) >= 127) ? 127 : (v))) + extern int32_t Echo [24000]; extern int32_t MixBuffer [SOUND_BUFFER_SIZE]; extern int32_t EchoBuffer [SOUND_BUFFER_SIZE]; @@ -89,6 +82,15 @@ uint32_t KeyOffERate [10]; #define LAST_SAMPLE 0xffffff #define JUST_PLAYED_LAST_SAMPLE(c) ((c)->sample_pointer >= LAST_SAMPLE) +/* Used by S9xMixSamplesLowPass() to store the + * last output samples for the next iteration + * of the low pass filter. This should go in + * the SSoundData struct, but doing so would + * break compatibility with existing save + * states (with little in the way of tangible + * benefits) */ +static int32_t MixOutputPrev[2]; + static INLINE uint8_t* S9xGetSampleAddress(int32_t sample_number) { uint32_t addr = (((APU.DSP[APU_DIR] << 8) + (sample_number << 2)) & 0xffff); @@ -807,6 +809,102 @@ void S9xMixSamples(int16_t* buffer, int32_t sample_count) } } +void S9xMixSamplesLowPass(int16_t* buffer, int32_t sample_count, int32_t low_pass_range) +{ + int32_t J; + int32_t I; + + /* Single-pole low-pass filter (6 dB/octave) */ + int32_t low_pass_factor_a = low_pass_range; + int32_t low_pass_factor_b = 0x10000 - low_pass_factor_a; + + if (SoundData.echo_enable) + memset(EchoBuffer, 0, sample_count * sizeof(EchoBuffer [0])); + memset(MixBuffer, 0, sample_count * sizeof(MixBuffer [0])); + MixStereo(sample_count); + + /* Mix and convert waveforms */ + if (SoundData.echo_enable && SoundData.echo_buffer_size) + { + /* 16-bit stereo sound with echo enabled ... */ + if (FilterTapDefinitionBitfield == 0) + { + /* ... but no filter defined. */ + for (J = 0; J < sample_count; J++) + { + int32_t *low_pass_sample = &MixOutputPrev[J & 0x1]; + int32_t E = Echo [SoundData.echo_ptr]; + Echo[SoundData.echo_ptr++] = (E * SoundData.echo_feedback) / 128 + EchoBuffer [J]; + + if (SoundData.echo_ptr >= SoundData.echo_buffer_size) + SoundData.echo_ptr = 0; + + I = (MixBuffer[J] * SoundData.master_volume [J & 1] + E * SoundData.echo_volume [J & 1]) / VOL_DIV16; + CLIP16(I); + + /* Apply low-pass filter */ + (*low_pass_sample) = ((*low_pass_sample) * low_pass_factor_a) + (I * low_pass_factor_b); + /* 16.16 fixed point */ + (*low_pass_sample) >>= 16; + + buffer[J] = (int16_t)(*low_pass_sample); + } + } + else + { + /* ... with filter defined. */ + for (J = 0; J < sample_count; J++) + { + int32_t *low_pass_sample = &MixOutputPrev[J & 0x1]; + int32_t E; + Loop [(Z - 0) & 15] = Echo [SoundData.echo_ptr]; + E = Loop [(Z - 0) & 15] * FilterTaps [0]; + if (FilterTapDefinitionBitfield & 0x02) E += Loop [(Z - 2) & 15] * FilterTaps [1]; + if (FilterTapDefinitionBitfield & 0x04) E += Loop [(Z - 4) & 15] * FilterTaps [2]; + if (FilterTapDefinitionBitfield & 0x08) E += Loop [(Z - 6) & 15] * FilterTaps [3]; + if (FilterTapDefinitionBitfield & 0x10) E += Loop [(Z - 8) & 15] * FilterTaps [4]; + if (FilterTapDefinitionBitfield & 0x20) E += Loop [(Z - 10) & 15] * FilterTaps [5]; + if (FilterTapDefinitionBitfield & 0x40) E += Loop [(Z - 12) & 15] * FilterTaps [6]; + if (FilterTapDefinitionBitfield & 0x80) E += Loop [(Z - 14) & 15] * FilterTaps [7]; + E /= 128; + Z++; + + Echo[SoundData.echo_ptr++] = (E * SoundData.echo_feedback) / 128 + EchoBuffer[J]; + + if (SoundData.echo_ptr >= SoundData.echo_buffer_size) + SoundData.echo_ptr = 0; + + I = (MixBuffer[J] * SoundData.master_volume [J & 1] + E * SoundData.echo_volume [J & 1]) / VOL_DIV16; + CLIP16(I); + + /* Apply low-pass filter */ + (*low_pass_sample) = ((*low_pass_sample) * low_pass_factor_a) + (I * low_pass_factor_b); + /* 16.16 fixed point */ + (*low_pass_sample) >>= 16; + + buffer[J] = (int16_t)(*low_pass_sample); + } + } + } + else + { + /* 16-bit mono or stereo sound, no echo */ + for (J = 0; J < sample_count; J++) + { + int32_t *low_pass_sample = &MixOutputPrev[J & 0x1]; + I = (MixBuffer[J] * SoundData.master_volume [J & 1]) / VOL_DIV16; + CLIP16(I); + + /* Apply low-pass filter */ + (*low_pass_sample) = ((*low_pass_sample) * low_pass_factor_a) + (I * low_pass_factor_b); + /* 16.16 fixed point */ + (*low_pass_sample) >>= 16; + + buffer[J] = (int16_t)(*low_pass_sample); + } + } +} + void S9xResetSound(bool full) { int32_t i; @@ -866,6 +964,8 @@ void S9xResetSound(bool full) SoundData.master_volume [0] = SoundData.master_volume [1] = 127; so.mute_sound = true; + + memset(MixOutputPrev, 0, sizeof(MixOutputPrev)); } void S9xSetPlaybackRate(uint32_t playback_rate) diff --git a/source/soundux.h b/source/soundux.h index 5cb4218..8a0e02e 100644 --- a/source/soundux.h +++ b/source/soundux.h @@ -135,6 +135,7 @@ void S9xFixEnvelope(int32_t channel, uint8_t gain, uint8_t adsr1, uint8_t adsr2) void S9xStartSample(int32_t channel); void S9xMixSamples(int16_t* buffer, int32_t sample_count); +void S9xMixSamplesLowPass(int16_t* buffer, int32_t sample_count, int32_t low_pass_range); void S9xSetPlaybackRate(uint32_t rate); #endif #endif |