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townengine/third-party/libxm/src/play.c
veclavtalica 329ef82747 push third-party/libxm
2024-07-08 18:01:08 +03:00

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/* Author: Romain "Artefact2" Dalmaso <artefact2@gmail.com> */
/* Contributor: Daniel Oaks <daniel@danieloaks.net> */
/* This program is free software. It comes without any warranty, to the
* extent permitted by applicable law. You can redistribute it and/or
* modify it under the terms of the Do What The Fuck You Want To Public
* License, Version 2, as published by Sam Hocevar. See
* http://sam.zoy.org/wtfpl/COPYING for more details. */
#include "xm_internal.h"
#include <inttypes.h>
/* ----- Static functions ----- */
static float xm_waveform(xm_waveform_type_t, uint8_t);
static void xm_autovibrato(xm_context_t*, xm_channel_context_t*);
static void xm_vibrato(xm_context_t*, xm_channel_context_t*, uint8_t);
static void xm_tremolo(xm_context_t*, xm_channel_context_t*, uint8_t, uint16_t);
static void xm_arpeggio(xm_context_t*, xm_channel_context_t*, uint8_t, uint16_t);
static void xm_tone_portamento(xm_context_t*, xm_channel_context_t*);
static void xm_pitch_slide(xm_context_t*, xm_channel_context_t*, float);
static void xm_panning_slide(xm_channel_context_t*, uint8_t);
static void xm_volume_slide(xm_channel_context_t*, uint8_t);
static float xm_envelope_lerp(xm_envelope_point_t*, xm_envelope_point_t*, uint16_t);
static void xm_envelope_tick(xm_channel_context_t*, xm_envelope_t*, uint16_t*, float*);
static void xm_envelopes(xm_channel_context_t*);
static float xm_linear_period(float);
static float xm_linear_frequency(float);
static float xm_amiga_period(float);
static float xm_amiga_frequency(float);
static float xm_period(xm_context_t*, float);
static float xm_frequency(xm_context_t*, float, float, float);
static void xm_update_frequency(xm_context_t*, xm_channel_context_t*);
static void xm_handle_note_and_instrument(xm_context_t*, xm_channel_context_t*, xm_pattern_slot_t*);
static void xm_trigger_note(xm_context_t*, xm_channel_context_t*, unsigned int flags);
static void xm_cut_note(xm_channel_context_t*);
static void xm_key_off(xm_channel_context_t*);
static void xm_post_pattern_change(xm_context_t*);
static void xm_row(xm_context_t*);
static void xm_tick(xm_context_t*);
static float xm_sample_at(xm_sample_t*, size_t);
static float xm_next_of_sample(xm_channel_context_t*);
static bool xm_sample(xm_context_t*, float*, float*);
/* ----- Other oddities ----- */
#define XM_TRIGGER_KEEP_VOLUME (1 << 0)
#define XM_TRIGGER_KEEP_PERIOD (1 << 1)
#define XM_TRIGGER_KEEP_SAMPLE_POSITION (1 << 2)
#define XM_TRIGGER_KEEP_ENVELOPE (1 << 3)
#define AMIGA_FREQ_SCALE 1024
static const uint32_t amiga_frequencies[] = {
1712*AMIGA_FREQ_SCALE, 1616*AMIGA_FREQ_SCALE, 1525*AMIGA_FREQ_SCALE, 1440*AMIGA_FREQ_SCALE, /* C-2, C#2, D-2, D#2 */
1357*AMIGA_FREQ_SCALE, 1281*AMIGA_FREQ_SCALE, 1209*AMIGA_FREQ_SCALE, 1141*AMIGA_FREQ_SCALE, /* E-2, F-2, F#2, G-2 */
1077*AMIGA_FREQ_SCALE, 1017*AMIGA_FREQ_SCALE, 961*AMIGA_FREQ_SCALE, 907*AMIGA_FREQ_SCALE, /* G#2, A-2, A#2, B-2 */
856*AMIGA_FREQ_SCALE, /* C-3 */
};
static const float multi_retrig_add[] = {
0.f, -1.f, -2.f, -4.f, /* 0, 1, 2, 3 */
-8.f, -16.f, 0.f, 0.f, /* 4, 5, 6, 7 */
0.f, 1.f, 2.f, 4.f, /* 8, 9, A, B */
8.f, 16.f, 0.f, 0.f /* C, D, E, F */
};
static const float multi_retrig_multiply[] = {
1.f, 1.f, 1.f, 1.f, /* 0, 1, 2, 3 */
1.f, 1.f, .6666667f, .5f, /* 4, 5, 6, 7 */
1.f, 1.f, 1.f, 1.f, /* 8, 9, A, B */
1.f, 1.f, 1.5f, 2.f /* C, D, E, F */
};
#define XM_CLAMP_UP1F(vol, limit) do { \
if((vol) > (limit)) (vol) = (limit); \
} while(0)
#define XM_CLAMP_UP(vol) XM_CLAMP_UP1F((vol), 1.f)
#define XM_CLAMP_DOWN1F(vol, limit) do { \
if((vol) < (limit)) (vol) = (limit); \
} while(0)
#define XM_CLAMP_DOWN(vol) XM_CLAMP_DOWN1F((vol), .0f)
#define XM_CLAMP2F(vol, up, down) do { \
if((vol) > (up)) (vol) = (up); \
else if((vol) < (down)) (vol) = (down); \
} while(0)
#define XM_CLAMP(vol) XM_CLAMP2F((vol), 1.f, .0f)
#define XM_SLIDE_TOWARDS(val, goal, incr) do { \
if((val) > (goal)) { \
(val) -= (incr); \
XM_CLAMP_DOWN1F((val), (goal)); \
} else if((val) < (goal)) { \
(val) += (incr); \
XM_CLAMP_UP1F((val), (goal)); \
} \
} while(0)
#define XM_LERP(u, v, t) ((u) + (t) * ((v) - (u)))
#define XM_INVERSE_LERP(u, v, lerp) (((lerp) - (u)) / ((v) - (u)))
#define HAS_TONE_PORTAMENTO(s) ((s)->effect_type == 3 \
|| (s)->effect_type == 5 \
|| ((s)->volume_column >> 4) == 0xF)
#define HAS_ARPEGGIO(s) ((s)->effect_type == 0 \
&& (s)->effect_param != 0)
#define HAS_VIBRATO(s) ((s)->effect_type == 4 \
|| (s)->effect_type == 6 \
|| ((s)->volume_column >> 4) == 0xB)
#define NOTE_IS_VALID(n) ((n) > 0 && (n) < 97)
/* ----- Function definitions ----- */
static float xm_waveform(xm_waveform_type_t waveform, uint8_t step) {
static unsigned int next_rand = 24492;
step %= 0x40;
switch(waveform) {
case XM_SINE_WAVEFORM:
/* Why not use a table? For saving space, and because there's
* very very little actual performance gain. */
return -sinf(2.f * 3.141592f * (float)step / (float)0x40);
case XM_RAMP_DOWN_WAVEFORM:
/* Ramp down: 1.0f when step = 0; -1.0f when step = 0x40 */
return (float)(0x20 - step) / 0x20;
case XM_SQUARE_WAVEFORM:
/* Square with a 50% duty */
return (step >= 0x20) ? 1.f : -1.f;
case XM_RANDOM_WAVEFORM:
/* Use the POSIX.1-2001 example, just to be deterministic
* across different machines */
next_rand = next_rand * 1103515245 + 12345;
return (float)((next_rand >> 16) & 0x7FFF) / (float)0x4000 - 1.f;
case XM_RAMP_UP_WAVEFORM:
/* Ramp up: -1.f when step = 0; 1.f when step = 0x40 */
return (float)(step - 0x20) / 0x20;
default:
break;
}
return .0f;
}
static void xm_autovibrato(xm_context_t* ctx, xm_channel_context_t* ch) {
if(ch->instrument == NULL || ch->instrument->vibrato_depth == 0){
if (ch->autovibrato_note_offset){
ch->autovibrato_note_offset = 0.f;
xm_update_frequency(ctx, ch);
}
return;
}
xm_instrument_t* instr = ch->instrument;
float sweep = 1.f;
if(ch->autovibrato_ticks < instr->vibrato_sweep) {
/* No idea if this is correct, but it sounds close enough… */
sweep = XM_LERP(0.f, 1.f, (float)ch->autovibrato_ticks / (float)instr->vibrato_sweep);
}
unsigned int step = ((ch->autovibrato_ticks++) * instr->vibrato_rate) >> 2;
ch->autovibrato_note_offset = .25f * xm_waveform(instr->vibrato_type, step)
* (float)instr->vibrato_depth / (float)0xF * sweep;
xm_update_frequency(ctx, ch);
}
static void xm_vibrato(xm_context_t* ctx, xm_channel_context_t* ch, uint8_t param) {
ch->vibrato_ticks += (param >> 4);
ch->vibrato_note_offset =
-2.f
* xm_waveform(ch->vibrato_waveform, ch->vibrato_ticks)
* (float)(param & 0x0F) / (float)0xF;
xm_update_frequency(ctx, ch);
}
static void xm_tremolo(xm_context_t* ctx, xm_channel_context_t* ch, uint8_t param, uint16_t pos) {
unsigned int step = pos * (param >> 4);
/* Not so sure about this, it sounds correct by ear compared with
* MilkyTracker, but it could come from other bugs */
ch->tremolo_volume = -1.f * xm_waveform(ch->tremolo_waveform, step)
* (float)(param & 0x0F) / (float)0xF;
}
static void xm_arpeggio(xm_context_t* ctx, xm_channel_context_t* ch, uint8_t param, uint16_t tick) {
switch(tick % 3) {
case 0:
ch->arp_in_progress = false;
ch->arp_note_offset = 0;
break;
case 2:
ch->arp_in_progress = true;
ch->arp_note_offset = param >> 4;
break;
case 1:
ch->arp_in_progress = true;
ch->arp_note_offset = param & 0x0F;
break;
}
xm_update_frequency(ctx, ch);
}
static void xm_tone_portamento(xm_context_t* ctx, xm_channel_context_t* ch) {
/* 3xx called without a note, wait until we get an actual
* target note. */
if(ch->tone_portamento_target_period == 0.f) return;
if(ch->period != ch->tone_portamento_target_period) {
XM_SLIDE_TOWARDS(ch->period,
ch->tone_portamento_target_period,
(ctx->module.frequency_type == XM_LINEAR_FREQUENCIES ?
4.f : 1.f) * ch->tone_portamento_param
);
xm_update_frequency(ctx, ch);
}
}
static void xm_pitch_slide(xm_context_t* ctx, xm_channel_context_t* ch, float period_offset) {
/* Don't ask about the 4.f coefficient. I found mention of it
* nowhere. Found by ear™. */
if(ctx->module.frequency_type == XM_LINEAR_FREQUENCIES) {
period_offset *= 4.f;
}
ch->period += period_offset;
XM_CLAMP_DOWN(ch->period);
/* XXX: upper bound of period ? */
xm_update_frequency(ctx, ch);
}
static void xm_panning_slide(xm_channel_context_t* ch, uint8_t rawval) {
float f;
if((rawval & 0xF0) && (rawval & 0x0F)) {
/* Illegal state */
return;
}
if(rawval & 0xF0) {
/* Slide right */
f = (float)(rawval >> 4) / (float)0xFF;
ch->panning += f;
XM_CLAMP_UP(ch->panning);
} else {
/* Slide left */
f = (float)(rawval & 0x0F) / (float)0xFF;
ch->panning -= f;
XM_CLAMP_DOWN(ch->panning);
}
}
static void xm_volume_slide(xm_channel_context_t* ch, uint8_t rawval) {
float f;
if((rawval & 0xF0) && (rawval & 0x0F)) {
/* Illegal state */
return;
}
if(rawval & 0xF0) {
/* Slide up */
f = (float)(rawval >> 4) / (float)0x40;
ch->volume += f;
XM_CLAMP_UP(ch->volume);
} else {
/* Slide down */
f = (float)(rawval & 0x0F) / (float)0x40;
ch->volume -= f;
XM_CLAMP_DOWN(ch->volume);
}
}
static float xm_envelope_lerp(xm_envelope_point_t* restrict a, xm_envelope_point_t* restrict b, uint16_t pos) {
/* Linear interpolation between two envelope points */
if(pos <= a->frame) return a->value;
else if(pos >= b->frame) return b->value;
else {
float p = (float)(pos - a->frame) / (float)(b->frame - a->frame);
return a->value * (1 - p) + b->value * p;
}
}
static void xm_post_pattern_change(xm_context_t* ctx) {
/* Loop if necessary */
if(ctx->current_table_index >= ctx->module.length) {
ctx->current_table_index = ctx->module.restart_position;
}
}
static float xm_linear_period(float note) {
return 7680.f - note * 64.f;
}
static float xm_linear_frequency(float period) {
return 8363.f * powf(2.f, (4608.f - period) / 768.f);
}
static float xm_amiga_period(float note) {
unsigned int intnote = note;
uint8_t a = intnote % 12;
int8_t octave = note / 12.f - 2;
int32_t p1 = amiga_frequencies[a], p2 = amiga_frequencies[a + 1];
if(octave > 0) {
p1 >>= octave;
p2 >>= octave;
} else if(octave < 0) {
p1 <<= (-octave);
p2 <<= (-octave);
}
return XM_LERP(p1, p2, note - intnote) / AMIGA_FREQ_SCALE;
}
static float xm_amiga_frequency(float period) {
if(period == .0f) return .0f;
/* This is the PAL value. No reason to choose this one over the
* NTSC value. */
return 7093789.2f / (period * 2.f);
}
static float xm_period(xm_context_t* ctx, float note) {
switch(ctx->module.frequency_type) {
case XM_LINEAR_FREQUENCIES:
return xm_linear_period(note);
case XM_AMIGA_FREQUENCIES:
return xm_amiga_period(note);
}
return .0f;
}
static float xm_frequency(xm_context_t* ctx, float period, float note_offset, float period_offset) {
uint8_t a;
int8_t octave;
float note;
int32_t p1, p2;
switch(ctx->module.frequency_type) {
case XM_LINEAR_FREQUENCIES:
return xm_linear_frequency(period - 64.f * note_offset - 16.f * period_offset);
case XM_AMIGA_FREQUENCIES:
if(note_offset == 0) {
/* A chance to escape from insanity */
return xm_amiga_frequency(period + 16.f * period_offset);
}
/* FIXME: this is very crappy at best */
a = octave = 0;
/* Find the octave of the current period */
period *= AMIGA_FREQ_SCALE;
if(period > amiga_frequencies[0]) {
--octave;
while(period > (amiga_frequencies[0] << (-octave))) --octave;
} else if(period < amiga_frequencies[12]) {
++octave;
while(period < (amiga_frequencies[12] >> octave)) ++octave;
}
/* Find the smallest note closest to the current period */
for(uint8_t i = 0; i < 12; ++i) {
p1 = amiga_frequencies[i], p2 = amiga_frequencies[i + 1];
if(octave > 0) {
p1 >>= octave;
p2 >>= octave;
} else if(octave < 0) {
p1 <<= (-octave);
p2 <<= (-octave);
}
if(p2 <= period && period <= p1) {
a = i;
break;
}
}
if(XM_DEBUG && (p1 < period || p2 > period)) {
DEBUG("%" PRId32 " <= %f <= %" PRId32 " should hold but doesn't, this is a bug", p2, period, p1);
}
note = 12.f * (octave + 2) + a + XM_INVERSE_LERP(p1, p2, period);
return xm_amiga_frequency(xm_amiga_period(note + note_offset) + 16.f * period_offset);
}
return .0f;
}
static void xm_update_frequency(xm_context_t* ctx, xm_channel_context_t* ch) {
ch->frequency = xm_frequency(
ctx, ch->period,
ch->arp_note_offset,
ch->vibrato_note_offset + ch->autovibrato_note_offset
);
ch->step = ch->frequency / ctx->rate;
}
static void xm_handle_note_and_instrument(xm_context_t* ctx, xm_channel_context_t* ch,
xm_pattern_slot_t* s) {
if(s->instrument > 0) {
if(HAS_TONE_PORTAMENTO(ch->current) && ch->instrument != NULL && ch->sample != NULL) {
/* Tone portamento in effect, unclear stuff happens */
xm_trigger_note(ctx, ch, XM_TRIGGER_KEEP_PERIOD | XM_TRIGGER_KEEP_SAMPLE_POSITION);
} else if(s->note == 0 && ch->sample != NULL) {
/* Ghost instrument, trigger note */
/* Sample position is kept, but envelopes are reset */
xm_trigger_note(ctx, ch, XM_TRIGGER_KEEP_SAMPLE_POSITION);
} else if(s->instrument > ctx->module.num_instruments) {
/* Invalid instrument, Cut current note */
xm_cut_note(ch);
ch->instrument = NULL;
ch->sample = NULL;
} else {
ch->instrument = ctx->module.instruments + (s->instrument - 1);
}
}
if(NOTE_IS_VALID(s->note)) {
/* Yes, the real note number is s->note -1. Try finding
* THAT in any of the specs! :-) */
xm_instrument_t* instr = ch->instrument;
if(HAS_TONE_PORTAMENTO(ch->current) && instr != NULL && ch->sample != NULL) {
/* Tone portamento in effect */
ch->note = s->note + ch->sample->relative_note + ch->sample->finetune / 128.f - 1.f;
ch->tone_portamento_target_period = xm_period(ctx, ch->note);
} else if(instr == NULL || ch->instrument->num_samples == 0) {
/* Bad instrument */
xm_cut_note(ch);
} else {
if(instr->sample_of_notes[s->note - 1] < instr->num_samples) {
#if XM_RAMPING
for(unsigned int z = 0; z < XM_SAMPLE_RAMPING_POINTS; ++z) {
ch->end_of_previous_sample[z] = xm_next_of_sample(ch);
}
ch->frame_count = 0;
#endif
ch->sample = instr->samples + instr->sample_of_notes[s->note - 1];
ch->orig_note = ch->note = s->note + ch->sample->relative_note
+ ch->sample->finetune / 128.f - 1.f;
if(s->instrument > 0) {
xm_trigger_note(ctx, ch, 0);
} else {
/* Ghost note: keep old volume */
xm_trigger_note(ctx, ch, XM_TRIGGER_KEEP_VOLUME);
}
} else {
/* Bad sample */
xm_cut_note(ch);
}
}
} else if(s->note == 97) {
/* Key Off */
xm_key_off(ch);
}
switch(s->volume_column >> 4) {
case 0x5:
if(s->volume_column > 0x50) break;
case 0x1:
case 0x2:
case 0x3:
case 0x4:
/* Set volume */
ch->volume = (float)(s->volume_column - 0x10) / (float)0x40;
break;
case 0x8: /* Fine volume slide down */
xm_volume_slide(ch, s->volume_column & 0x0F);
break;
case 0x9: /* Fine volume slide up */
xm_volume_slide(ch, s->volume_column << 4);
break;
case 0xA: /* Set vibrato speed */
ch->vibrato_param = (ch->vibrato_param & 0x0F) | ((s->volume_column & 0x0F) << 4);
break;
case 0xC: /* Set panning */
ch->panning = (float)(
((s->volume_column & 0x0F) << 4) | (s->volume_column & 0x0F)
) / (float)0xFF;
break;
case 0xF: /* Tone portamento */
if(s->volume_column & 0x0F) {
ch->tone_portamento_param = ((s->volume_column & 0x0F) << 4)
| (s->volume_column & 0x0F);
}
break;
default:
break;
}
switch(s->effect_type) {
case 1: /* 1xx: Portamento up */
if(s->effect_param > 0) {
ch->portamento_up_param = s->effect_param;
}
break;
case 2: /* 2xx: Portamento down */
if(s->effect_param > 0) {
ch->portamento_down_param = s->effect_param;
}
break;
case 3: /* 3xx: Tone portamento */
if(s->effect_param > 0) {
ch->tone_portamento_param = s->effect_param;
}
break;
case 4: /* 4xy: Vibrato */
if(s->effect_param & 0x0F) {
/* Set vibrato depth */
ch->vibrato_param = (ch->vibrato_param & 0xF0) | (s->effect_param & 0x0F);
}
if(s->effect_param >> 4) {
/* Set vibrato speed */
ch->vibrato_param = (s->effect_param & 0xF0) | (ch->vibrato_param & 0x0F);
}
break;
case 5: /* 5xy: Tone portamento + Volume slide */
if(s->effect_param > 0) {
ch->volume_slide_param = s->effect_param;
}
break;
case 6: /* 6xy: Vibrato + Volume slide */
if(s->effect_param > 0) {
ch->volume_slide_param = s->effect_param;
}
break;
case 7: /* 7xy: Tremolo */
if(s->effect_param & 0x0F) {
/* Set tremolo depth */
ch->tremolo_param = (ch->tremolo_param & 0xF0) | (s->effect_param & 0x0F);
}
if(s->effect_param >> 4) {
/* Set tremolo speed */
ch->tremolo_param = (s->effect_param & 0xF0) | (ch->tremolo_param & 0x0F);
}
break;
case 8: /* 8xx: Set panning */
ch->panning = (float)s->effect_param / (float)0xFF;
break;
case 9: /* 9xx: Sample offset */
if(ch->sample != NULL && NOTE_IS_VALID(s->note)) {
uint32_t final_offset = s->effect_param << (ch->sample->bits == 16 ? 7 : 8);
if(final_offset >= ch->sample->length) {
/* Pretend the sample dosen't loop and is done playing */
ch->sample_position = -1;
break;
}
ch->sample_position = final_offset;
}
break;
case 0xA: /* Axy: Volume slide */
if(s->effect_param > 0) {
ch->volume_slide_param = s->effect_param;
}
break;
case 0xB: /* Bxx: Position jump */
if(s->effect_param < ctx->module.length) {
ctx->position_jump = true;
ctx->jump_dest = s->effect_param;
ctx->jump_row = 0;
}
break;
case 0xC: /* Cxx: Set volume */
ch->volume = (float)((s->effect_param > 0x40)
? 0x40 : s->effect_param) / (float)0x40;
break;
case 0xD: /* Dxx: Pattern break */
/* Jump after playing this line */
ctx->pattern_break = true;
ctx->jump_row = (s->effect_param >> 4) * 10 + (s->effect_param & 0x0F);
break;
case 0xE: /* EXy: Extended command */
switch(s->effect_param >> 4) {
case 1: /* E1y: Fine portamento up */
if(s->effect_param & 0x0F) {
ch->fine_portamento_up_param = s->effect_param & 0x0F;
}
xm_pitch_slide(ctx, ch, -ch->fine_portamento_up_param);
break;
case 2: /* E2y: Fine portamento down */
if(s->effect_param & 0x0F) {
ch->fine_portamento_down_param = s->effect_param & 0x0F;
}
xm_pitch_slide(ctx, ch, ch->fine_portamento_down_param);
break;
case 4: /* E4y: Set vibrato control */
ch->vibrato_waveform = s->effect_param & 3;
ch->vibrato_waveform_retrigger = !((s->effect_param >> 2) & 1);
break;
case 5: /* E5y: Set finetune */
if(NOTE_IS_VALID(ch->current->note) && ch->sample != NULL) {
ch->note = ch->current->note + ch->sample->relative_note +
(float)(((s->effect_param & 0x0F) - 8) << 4) / 128.f - 1.f;
ch->period = xm_period(ctx, ch->note);
xm_update_frequency(ctx, ch);
}
break;
case 6: /* E6y: Pattern loop */
if(s->effect_param & 0x0F) {
if((s->effect_param & 0x0F) == ch->pattern_loop_count) {
/* Loop is over */
ch->pattern_loop_count = 0;
break;
}
/* Jump to the beginning of the loop */
ch->pattern_loop_count++;
ctx->position_jump = true;
ctx->jump_row = ch->pattern_loop_origin;
ctx->jump_dest = ctx->current_table_index;
} else {
/* Set loop start point */
ch->pattern_loop_origin = ctx->current_row;
/* Replicate FT2 E60 bug */
ctx->jump_row = ch->pattern_loop_origin;
}
break;
case 7: /* E7y: Set tremolo control */
ch->tremolo_waveform = s->effect_param & 3;
ch->tremolo_waveform_retrigger = !((s->effect_param >> 2) & 1);
break;
case 0xA: /* EAy: Fine volume slide up */
if(s->effect_param & 0x0F) {
ch->fine_volume_slide_param = s->effect_param & 0x0F;
}
xm_volume_slide(ch, ch->fine_volume_slide_param << 4);
break;
case 0xB: /* EBy: Fine volume slide down */
if(s->effect_param & 0x0F) {
ch->fine_volume_slide_param = s->effect_param & 0x0F;
}
xm_volume_slide(ch, ch->fine_volume_slide_param);
break;
case 0xD: /* EDy: Note delay */
/* XXX: figure this out better. EDx triggers
* the note even when there no note and no
* instrument. But ED0 acts like like a ghost
* note, EDx (x ≠ 0) does not. */
if(s->note == 0 && s->instrument == 0) {
unsigned int flags = XM_TRIGGER_KEEP_VOLUME;
if(ch->current->effect_param & 0x0F) {
ch->note = ch->orig_note;
xm_trigger_note(ctx, ch, flags);
} else {
xm_trigger_note(
ctx, ch,
flags
| XM_TRIGGER_KEEP_PERIOD
| XM_TRIGGER_KEEP_SAMPLE_POSITION
);
}
}
break;
case 0xE: /* EEy: Pattern delay */
ctx->extra_ticks = (ch->current->effect_param & 0x0F) * ctx->tempo;
break;
default:
break;
}
break;
case 0xF: /* Fxx: Set tempo/BPM */
if(s->effect_param > 0) {
if(s->effect_param <= 0x1F) {
ctx->tempo = s->effect_param;
} else {
ctx->bpm = s->effect_param;
}
}
break;
case 16: /* Gxx: Set global volume */
ctx->global_volume = (float)((s->effect_param > 0x40)
? 0x40 : s->effect_param) / (float)0x40;
break;
case 17: /* Hxy: Global volume slide */
if(s->effect_param > 0) {
ch->global_volume_slide_param = s->effect_param;
}
break;
case 21: /* Lxx: Set envelope position */
ch->volume_envelope_frame_count = s->effect_param;
ch->panning_envelope_frame_count = s->effect_param;
break;
case 25: /* Pxy: Panning slide */
if(s->effect_param > 0) {
ch->panning_slide_param = s->effect_param;
}
break;
case 27: /* Rxy: Multi retrig note */
if(s->effect_param > 0) {
if((s->effect_param >> 4) == 0) {
/* Keep previous x value */
ch->multi_retrig_param = (ch->multi_retrig_param & 0xF0) | (s->effect_param & 0x0F);
} else {
ch->multi_retrig_param = s->effect_param;
}
}
break;
case 29: /* Txy: Tremor */
if(s->effect_param > 0) {
/* Tremor x and y params do not appear to be separately
* kept in memory, unlike Rxy */
ch->tremor_param = s->effect_param;
}
break;
case 33: /* Xxy: Extra stuff */
switch(s->effect_param >> 4) {
case 1: /* X1y: Extra fine portamento up */
if(s->effect_param & 0x0F) {
ch->extra_fine_portamento_up_param = s->effect_param & 0x0F;
}
xm_pitch_slide(ctx, ch, -1.0f * ch->extra_fine_portamento_up_param);
break;
case 2: /* X2y: Extra fine portamento down */
if(s->effect_param & 0x0F) {
ch->extra_fine_portamento_down_param = s->effect_param & 0x0F;
}
xm_pitch_slide(ctx, ch, ch->extra_fine_portamento_down_param);
break;
default:
break;
}
break;
default:
break;
}
}
static void xm_trigger_note(xm_context_t* ctx, xm_channel_context_t* ch, unsigned int flags) {
if(!(flags & XM_TRIGGER_KEEP_SAMPLE_POSITION)) {
ch->sample_position = 0.f;
ch->ping = true;
}
if(ch->sample != NULL) {
if(!(flags & XM_TRIGGER_KEEP_VOLUME)) {
ch->volume = ch->sample->volume;
}
ch->panning = ch->sample->panning;
}
if(!(flags & XM_TRIGGER_KEEP_ENVELOPE)) {
ch->sustained = true;
ch->fadeout_volume = ch->volume_envelope_volume = 1.0f;
ch->panning_envelope_panning = .5f;
ch->volume_envelope_frame_count = ch->panning_envelope_frame_count = 0;
}
ch->vibrato_note_offset = 0.f;
ch->tremolo_volume = 0.f;
ch->tremor_on = false;
ch->autovibrato_ticks = 0;
if(ch->vibrato_waveform_retrigger) {
ch->vibrato_ticks = 0; /* XXX: should the waveform itself also
* be reset to sine? */
}
if(ch->tremolo_waveform_retrigger) {
ch->tremolo_ticks = 0;
}
if(!(flags & XM_TRIGGER_KEEP_PERIOD)) {
ch->period = xm_period(ctx, ch->note);
xm_update_frequency(ctx, ch);
}
ch->latest_trigger = ctx->generated_samples;
if(ch->instrument != NULL) {
ch->instrument->latest_trigger = ctx->generated_samples;
}
if(ch->sample != NULL) {
ch->sample->latest_trigger = ctx->generated_samples;
}
}
static void xm_cut_note(xm_channel_context_t* ch) {
/* NB: this is not the same as Key Off */
ch->volume = .0f;
}
static void xm_key_off(xm_channel_context_t* ch) {
/* Key Off */
ch->sustained = false;
/* If no volume envelope is used, also cut the note */
if(ch->instrument == NULL || !ch->instrument->volume_envelope.enabled) {
xm_cut_note(ch);
}
}
static void xm_row(xm_context_t* ctx) {
static xm_pattern_slot_t empty_slot = {0};
if(ctx->position_jump) {
ctx->current_table_index = ctx->jump_dest;
ctx->current_row = ctx->jump_row;
ctx->position_jump = false;
ctx->pattern_break = false;
ctx->jump_row = 0;
xm_post_pattern_change(ctx);
} else if(ctx->pattern_break) {
ctx->current_table_index++;
ctx->current_row = ctx->jump_row;
ctx->pattern_break = false;
ctx->jump_row = 0;
xm_post_pattern_change(ctx);
}
uint8_t pat_idx = ctx->module.pattern_table[ctx->current_table_index];
xm_pattern_t* cur = (pat_idx < ctx->module.num_patterns ? ctx->module.patterns + pat_idx : NULL);
bool in_a_loop = false;
/* Read notes… */
for(uint8_t i = 0; i < ctx->module.num_channels; ++i) {
xm_pattern_slot_t* s = (cur ? cur->slots + ctx->current_row * ctx->module.num_channels + i : &empty_slot);
xm_channel_context_t* ch = ctx->channels + i;
ch->current = s;
if(s->effect_type != 0xE || s->effect_param >> 4 != 0xD) {
xm_handle_note_and_instrument(ctx, ch, s);
} else {
ch->note_delay_param = s->effect_param & 0x0F;
}
if(!in_a_loop && ch->pattern_loop_count > 0) {
in_a_loop = true;
}
}
if(!in_a_loop) {
/* No E6y loop is in effect (or we are in the first pass) */
ctx->loop_count = (ctx->row_loop_count[MAX_NUM_ROWS * ctx->current_table_index + ctx->current_row]++);
}
ctx->current_row++; /* Since this is an uint8, this line can
* increment from 255 to 0, in which case it
* is still necessary to go the next
* pattern. */
if(!ctx->position_jump && !ctx->pattern_break &&
(ctx->current_row >= (cur ? cur->num_rows : DEFAULT_PATTERN_LENGTH) || ctx->current_row == 0)) {
ctx->current_table_index++;
ctx->current_row = ctx->jump_row; /* This will be 0 most of
* the time, except when E60
* is used */
ctx->jump_row = 0;
xm_post_pattern_change(ctx);
}
}
static void xm_envelope_tick(xm_channel_context_t* ch,
xm_envelope_t* env,
uint16_t* counter,
float* outval) {
if(env->num_points < 2) {
/* Don't really know what to do… */
if(env->num_points == 1) {
/* XXX I am pulling this out of my ass */
*outval = (float)env->points[0].value / (float)0x40;
if(*outval > 1) {
*outval = 1;
}
}
return;
} else {
uint8_t j;
if(env->loop_enabled) {
uint16_t loop_start = env->points[env->loop_start_point].frame;
uint16_t loop_end = env->points[env->loop_end_point].frame;
uint16_t loop_length = loop_end - loop_start;
if(*counter >= loop_end) {
*counter -= loop_length;
}
}
for(j = 0; j < (env->num_points - 2); ++j) {
if(env->points[j].frame <= *counter &&
env->points[j+1].frame >= *counter) {
break;
}
}
*outval = xm_envelope_lerp(env->points + j, env->points + j + 1, *counter) / (float)0x40;
/* Make sure it is safe to increment frame count */
if(!ch->sustained || !env->sustain_enabled ||
*counter != env->points[env->sustain_point].frame) {
(*counter)++;
}
}
}
static void xm_envelopes(xm_channel_context_t* ch) {
if(ch->instrument != NULL) {
if(ch->instrument->volume_envelope.enabled) {
if(!ch->sustained) {
ch->fadeout_volume -= (float)ch->instrument->volume_fadeout / 32768.f;
XM_CLAMP_DOWN(ch->fadeout_volume);
}
xm_envelope_tick(ch,
&(ch->instrument->volume_envelope),
&(ch->volume_envelope_frame_count),
&(ch->volume_envelope_volume));
}
if(ch->instrument->panning_envelope.enabled) {
xm_envelope_tick(ch,
&(ch->instrument->panning_envelope),
&(ch->panning_envelope_frame_count),
&(ch->panning_envelope_panning));
}
}
}
static void xm_tick(xm_context_t* ctx) {
if(ctx->current_tick == 0) {
xm_row(ctx);
}
for(uint8_t i = 0; i < ctx->module.num_channels; ++i) {
xm_channel_context_t* ch = ctx->channels + i;
xm_envelopes(ch);
xm_autovibrato(ctx, ch);
if(ch->arp_in_progress && !HAS_ARPEGGIO(ch->current)) {
ch->arp_in_progress = false;
ch->arp_note_offset = 0;
xm_update_frequency(ctx, ch);
}
if(ch->vibrato_in_progress && !HAS_VIBRATO(ch->current)) {
ch->vibrato_in_progress = false;
ch->vibrato_note_offset = 0.f;
xm_update_frequency(ctx, ch);
}
switch(ch->current->volume_column >> 4) {
case 0x6: /* Volume slide down */
if(ctx->current_tick == 0) break;
xm_volume_slide(ch, ch->current->volume_column & 0x0F);
break;
case 0x7: /* Volume slide up */
if(ctx->current_tick == 0) break;
xm_volume_slide(ch, ch->current->volume_column << 4);
break;
case 0xB: /* Vibrato */
if(ctx->current_tick == 0) break;
ch->vibrato_in_progress = false;
xm_vibrato(ctx, ch, ch->vibrato_param);
break;
case 0xD: /* Panning slide left */
if(ctx->current_tick == 0) break;
xm_panning_slide(ch, ch->current->volume_column & 0x0F);
break;
case 0xE: /* Panning slide right */
if(ctx->current_tick == 0) break;
xm_panning_slide(ch, ch->current->volume_column << 4);
break;
case 0xF: /* Tone portamento */
if(ctx->current_tick == 0) break;
xm_tone_portamento(ctx, ch);
break;
default:
break;
}
switch(ch->current->effect_type) {
case 0: /* 0xy: Arpeggio */
if(ch->current->effect_param > 0) {
char arp_offset = ctx->tempo % 3;
switch(arp_offset) {
case 2: /* 0 -> x -> 0 -> y -> x -> … */
if(ctx->current_tick == 1) {
ch->arp_in_progress = true;
ch->arp_note_offset = ch->current->effect_param >> 4;
xm_update_frequency(ctx, ch);
break;
}
/* No break here, this is intended */
case 1: /* 0 -> 0 -> y -> x -> … */
if(ctx->current_tick == 0) {
ch->arp_in_progress = false;
ch->arp_note_offset = 0;
xm_update_frequency(ctx, ch);
break;
}
/* No break here, this is intended */
case 0: /* 0 -> y -> x -> … */
xm_arpeggio(ctx, ch, ch->current->effect_param, ctx->current_tick - arp_offset);
default:
break;
}
}
break;
case 1: /* 1xx: Portamento up */
if(ctx->current_tick == 0) break;
xm_pitch_slide(ctx, ch, -ch->portamento_up_param);
break;
case 2: /* 2xx: Portamento down */
if(ctx->current_tick == 0) break;
xm_pitch_slide(ctx, ch, ch->portamento_down_param);
break;
case 3: /* 3xx: Tone portamento */
if(ctx->current_tick == 0) break;
xm_tone_portamento(ctx, ch);
break;
case 4: /* 4xy: Vibrato */
if(ctx->current_tick == 0) break;
ch->vibrato_in_progress = true;
xm_vibrato(ctx, ch, ch->vibrato_param);
break;
case 5: /* 5xy: Tone portamento + Volume slide */
if(ctx->current_tick == 0) break;
xm_tone_portamento(ctx, ch);
xm_volume_slide(ch, ch->volume_slide_param);
break;
case 6: /* 6xy: Vibrato + Volume slide */
if(ctx->current_tick == 0) break;
ch->vibrato_in_progress = true;
xm_vibrato(ctx, ch, ch->vibrato_param);
xm_volume_slide(ch, ch->volume_slide_param);
break;
case 7: /* 7xy: Tremolo */
if(ctx->current_tick == 0) break;
xm_tremolo(ctx, ch, ch->tremolo_param, ch->tremolo_ticks++);
break;
case 0xA: /* Axy: Volume slide */
if(ctx->current_tick == 0) break;
xm_volume_slide(ch, ch->volume_slide_param);
break;
case 0xE: /* EXy: Extended command */
switch(ch->current->effect_param >> 4) {
case 0x9: /* E9y: Retrigger note */
if(ctx->current_tick != 0 && ch->current->effect_param & 0x0F) {
if(!(ctx->current_tick % (ch->current->effect_param & 0x0F))) {
xm_trigger_note(ctx, ch, XM_TRIGGER_KEEP_VOLUME);
xm_envelopes(ch);
}
}
break;
case 0xC: /* ECy: Note cut */
if((ch->current->effect_param & 0x0F) == ctx->current_tick) {
xm_cut_note(ch);
}
break;
case 0xD: /* EDy: Note delay */
if(ch->note_delay_param == ctx->current_tick) {
xm_handle_note_and_instrument(ctx, ch, ch->current);
xm_envelopes(ch);
}
break;
default:
break;
}
break;
case 17: /* Hxy: Global volume slide */
if(ctx->current_tick == 0) break;
if((ch->global_volume_slide_param & 0xF0) &&
(ch->global_volume_slide_param & 0x0F)) {
/* Illegal state */
break;
}
if(ch->global_volume_slide_param & 0xF0) {
/* Global slide up */
float f = (float)(ch->global_volume_slide_param >> 4) / (float)0x40;
ctx->global_volume += f;
XM_CLAMP_UP(ctx->global_volume);
} else {
/* Global slide down */
float f = (float)(ch->global_volume_slide_param & 0x0F) / (float)0x40;
ctx->global_volume -= f;
XM_CLAMP_DOWN(ctx->global_volume);
}
break;
case 20: /* Kxx: Key off */
/* Most documentations will tell you the parameter has no
* use. Don't be fooled. */
if(ctx->current_tick == ch->current->effect_param) {
xm_key_off(ch);
}
break;
case 25: /* Pxy: Panning slide */
if(ctx->current_tick == 0) break;
xm_panning_slide(ch, ch->panning_slide_param);
break;
case 27: /* Rxy: Multi retrig note */
if(ctx->current_tick == 0) break;
if(((ch->multi_retrig_param) & 0x0F) == 0) break;
if((ctx->current_tick % (ch->multi_retrig_param & 0x0F)) == 0) {
xm_trigger_note(ctx, ch, XM_TRIGGER_KEEP_VOLUME | XM_TRIGGER_KEEP_ENVELOPE);
/* Rxy doesn't affect volume if there's a command in the volume
column, or if the instrument has a volume envelope. */
if (!ch->current->volume_column && !ch->instrument->volume_envelope.enabled){
float v = ch->volume * multi_retrig_multiply[ch->multi_retrig_param >> 4]
+ multi_retrig_add[ch->multi_retrig_param >> 4] / (float)0x40;
XM_CLAMP(v);
ch->volume = v;
}
}
break;
case 29: /* Txy: Tremor */
if(ctx->current_tick == 0) break;
ch->tremor_on = (
(ctx->current_tick - 1) % ((ch->tremor_param >> 4) + (ch->tremor_param & 0x0F) + 2)
>
(ch->tremor_param >> 4)
);
break;
default:
break;
}
float panning, volume;
panning = ch->panning +
(ch->panning_envelope_panning - .5f) * (.5f - fabsf(ch->panning - .5f)) * 2.0f;
if(ch->tremor_on) {
volume = .0f;
} else {
volume = ch->volume + ch->tremolo_volume;
XM_CLAMP(volume);
volume *= ch->fadeout_volume * ch->volume_envelope_volume;
}
#if XM_RAMPING
/* See https://modarchive.org/forums/index.php?topic=3517.0
* and https://github.com/Artefact2/libxm/pull/16 */
ch->target_volume[0] = volume * sqrtf(1.f - panning);
ch->target_volume[1] = volume * sqrtf(panning);
#else
ch->actual_volume[0] = volume * sqrtf(1.f - panning);
ch->actual_volume[1] = volume * sqrtf(panning);
#endif
}
ctx->current_tick++;
if(ctx->current_tick >= ctx->tempo + ctx->extra_ticks) {
ctx->current_tick = 0;
ctx->extra_ticks = 0;
}
/* FT2 manual says number of ticks / second = BPM * 0.4 */
ctx->remaining_samples_in_tick += (float)ctx->rate / ((float)ctx->bpm * 0.4f);
}
static float xm_sample_at(xm_sample_t* sample, size_t k) {
return sample->bits == 8 ? (sample->data8[k] / 128.f) : (sample->data16[k] / 32768.f);
}
static float xm_next_of_sample(xm_channel_context_t* ch) {
if(ch->instrument == NULL || ch->sample == NULL || ch->sample_position < 0) {
#if XM_RAMPING
if(ch->frame_count < XM_SAMPLE_RAMPING_POINTS) {
return XM_LERP(ch->end_of_previous_sample[ch->frame_count], .0f,
(float)ch->frame_count / (float)XM_SAMPLE_RAMPING_POINTS);
}
#endif
return .0f;
}
if(ch->sample->length == 0) {
return .0f;
}
float u, v, t;
uint32_t a, b;
a = (uint32_t)ch->sample_position; /* This cast is fine,
* sample_position will not
* go above integer
* ranges */
if(XM_LINEAR_INTERPOLATION) {
b = a + 1;
t = ch->sample_position - a; /* Cheaper than fmodf(., 1.f) */
}
u = xm_sample_at(ch->sample, a);
switch(ch->sample->loop_type) {
case XM_NO_LOOP:
if(XM_LINEAR_INTERPOLATION) {
v = (b < ch->sample->length) ? xm_sample_at(ch->sample, b) : .0f;
}
ch->sample_position += ch->step;
if(ch->sample_position >= ch->sample->length) {
ch->sample_position = -1;
}
break;
case XM_FORWARD_LOOP:
if(XM_LINEAR_INTERPOLATION) {
v = xm_sample_at(
ch->sample,
(b == ch->sample->loop_end) ? ch->sample->loop_start : b
);
}
ch->sample_position += ch->step;
while(ch->sample_position >= ch->sample->loop_end) {
ch->sample_position -= ch->sample->loop_length;
}
break;
case XM_PING_PONG_LOOP:
if(ch->ping) {
ch->sample_position += ch->step;
} else {
ch->sample_position -= ch->step;
}
/* XXX: this may not work for very tight ping-pong loops
* (ie switches direction more than once per sample */
if(ch->ping) {
if(XM_LINEAR_INTERPOLATION) {
v = xm_sample_at(ch->sample, (b >= ch->sample->loop_end) ? a : b);
}
if(ch->sample_position >= ch->sample->loop_end) {
ch->ping = false;
ch->sample_position = (ch->sample->loop_end << 1) - ch->sample_position;
}
/* sanity checking */
if(ch->sample_position >= ch->sample->length) {
ch->ping = false;
ch->sample_position -= ch->sample->length - 1;
}
} else {
if(XM_LINEAR_INTERPOLATION) {
v = u;
u = xm_sample_at(
ch->sample,
(b == 1 || b - 2 <= ch->sample->loop_start) ? a : (b - 2)
);
}
if(ch->sample_position <= ch->sample->loop_start) {
ch->ping = true;
ch->sample_position = (ch->sample->loop_start << 1) - ch->sample_position;
}
/* sanity checking */
if(ch->sample_position <= .0f) {
ch->ping = true;
ch->sample_position = .0f;
}
}
break;
default:
v = .0f;
break;
}
float endval = (XM_LINEAR_INTERPOLATION ? XM_LERP(u, v, t) : u);
#if XM_RAMPING
if(ch->frame_count < XM_SAMPLE_RAMPING_POINTS) {
/* Smoothly transition between old and new sample. */
return XM_LERP(ch->end_of_previous_sample[ch->frame_count], endval,
(float)ch->frame_count / (float)XM_SAMPLE_RAMPING_POINTS);
}
#endif
return endval;
}
static bool xm_sample(xm_context_t* ctx, float* left, float* right) {
if(ctx->remaining_samples_in_tick <= 0) {
xm_tick(ctx);
}
ctx->remaining_samples_in_tick--;
*left = 0.f;
*right = 0.f;
if(ctx->max_loop_count > 0 && ctx->loop_count >= ctx->max_loop_count) {
return false;
}
for(uint8_t i = 0; i < ctx->module.num_channels; ++i) {
xm_channel_context_t* ch = ctx->channels + i;
if(ch->instrument == NULL || ch->sample == NULL || ch->sample_position < 0) {
continue;
}
const float fval = xm_next_of_sample(ch);
if(!ch->muted && !ch->instrument->muted) {
*left += fval * ch->actual_volume[0];
*right += fval * ch->actual_volume[1];
}
#if XM_RAMPING
ch->frame_count++;
XM_SLIDE_TOWARDS(ch->actual_volume[0], ch->target_volume[0], ctx->volume_ramp);
XM_SLIDE_TOWARDS(ch->actual_volume[1], ch->target_volume[1], ctx->volume_ramp);
#endif
}
const float fgvol = ctx->global_volume * ctx->amplification;
*left *= fgvol;
*right *= fgvol;
if(XM_DEBUG) {
if(fabs(*left) > 1 || fabs(*right) > 1) {
DEBUG("clipping frame: %f %f, this is a bad module or a libxm bug", *left, *right);
}
}
return true;
}
int xm_generate_samples(xm_context_t* ctx, float* output, size_t numsamples) {
int generated_samples = 0;
for(size_t i = 0; i < numsamples; i++, generated_samples++) {
if (!xm_sample(ctx, output + (2 * i), output + (2 * i + 1)))
break;
}
ctx->generated_samples += generated_samples;
return generated_samples;
}
void xm_restart(xm_context_t* ctx) {
xm_seek(ctx, 0, 0, 0);
ctx->loop_count = 0;
ctx->generated_samples = 0;
memset(ctx->row_loop_count, 0, ctx->module.length * MAX_NUM_ROWS * sizeof(uint8_t));
}
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