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Merge pull request #261 from shorepine/partials-interp
C version of piano partials
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@@ -32,6 +32,7 @@ if (TARGET tinyusb_device) | |
| examples.c | ||
| oscillators.c | ||
| partials.c | ||
| interp_partials.c | ||
| pcm.c | ||
| ) | ||
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,149 @@ | ||
| // interp_partials - AMY kernel-side implementation of the interpolated partials-based synthesis originally implemented in tulip_piano.py. | ||
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| #include "amy.h" | ||
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| typedef struct { | ||
| // How many sample_times_ms are there? | ||
| uint16_t num_sample_times_ms; | ||
| // Pointer to an array of the sample_times_ms | ||
| const uint16_t *sample_times_ms; | ||
| // How many velocities are defined for this voice (same for all notes) | ||
| uint16_t num_velocities; | ||
| // Pointer to a array of the MIDI velocities. | ||
| const uint8_t *velocities; | ||
| // How many different pitches do we define? (All velocities are provided for each) | ||
| uint16_t num_pitches; | ||
| // Pointer to array of structures defining each note (pitch + velocity) entry. | ||
| const uint8_t *pitches; | ||
| // How many harmonics are allocated for each of the num_velocities * num_pitches notes. | ||
| const uint8_t *num_harmonics; | ||
| // MIDI Cents freqs for each harmonic. | ||
| const uint16_t *harmonics_freq; | ||
| // num_sample_times_ms uint8_t dB envelope values for each harmonic. | ||
| const uint8_t *harmonics_mags; | ||
| } interp_partials_voice_t; | ||
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| #include "interp_partials.h" | ||
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| #define MAX_NUM_MAGNITUDES 24 | ||
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| void _cumulate_scaled_harmonic_params(float *harm_param, int harmonic_index, float alpha, const interp_partials_voice_t *partials_voice) { | ||
| int num_bps = partials_voice->num_sample_times_ms; | ||
| // Pitch | ||
| harm_param[0] += alpha * partials_voice->harmonics_freq[harmonic_index]; | ||
| // Envelope magnitudes | ||
| for (int i = 0; i < num_bps; ++i) | ||
| harm_param[1 + i] += alpha * partials_voice->harmonics_mags[harmonic_index * num_bps + i]; | ||
| } | ||
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| int _harmonic_base_index_for_pitch_vel(int pitch_index, int vel_index, const interp_partials_voice_t *partials_voice) { | ||
| int note_number = partials_voice->num_velocities * pitch_index + vel_index; | ||
| int harmonic_index = 0; | ||
| for (int i = 0; i < note_number; ++i) | ||
| harmonic_index += partials_voice->num_harmonics[i]; | ||
| return harmonic_index; | ||
| } | ||
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| float _logfreq_of_midi_cents(float midi_cents) { | ||
| // Frequency is already log scaled, but need to re-center and change from 1200/oct to 1.0/oct. | ||
| return (midi_cents - (100 * ZERO_MIDI_NOTE)) / 1200.f; | ||
| } | ||
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| float _env_lin_of_db(float db) { | ||
| float lin = powf(10.f, (db - 100) / 20.f) - 0.001; | ||
| if (lin < 0) return 0; | ||
| return lin; | ||
| } | ||
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| void _osc_on_with_harm_param(uint16_t o, float *harm_param, const interp_partials_voice_t *partials_voice) { | ||
| // We coerce this voice into being a partial, regardless of user wishes. | ||
| synth[o].wave = PARTIAL; | ||
| synth[o].patch = -1; // Flag that this is an envelope-based partial | ||
| // Setup the specified frequency. | ||
| synth[o].logfreq_coefs[COEF_CONST] = _logfreq_of_midi_cents(harm_param[0]); | ||
| // Setup envelope. | ||
| synth[o].breakpoint_times[0][0] = 0; | ||
| synth[o].breakpoint_values[0][0] = 0; | ||
| int last_time = 0; | ||
| for (int bp = 0; bp < partials_voice->num_sample_times_ms; ++bp) { | ||
| synth[o].breakpoint_times[0][bp + 1] = (partials_voice->sample_times_ms[bp] - last_time) * AMY_SAMPLE_RATE / 1000; | ||
| synth[o].breakpoint_values[0][bp + 1] = _env_lin_of_db(harm_param[bp + 1]); | ||
| last_time = partials_voice->sample_times_ms[bp]; | ||
| } | ||
| // Final release | ||
| synth[o].breakpoint_times[0][partials_voice->num_sample_times_ms + 1] = 200 * AMY_SAMPLE_RATE / 1000; | ||
| synth[o].breakpoint_values[0][partials_voice->num_sample_times_ms + 1] = 0; | ||
| // Decouple osc freq and amp from note and amp. | ||
| synth[o].logfreq_coefs[COEF_NOTE] = 0; | ||
| synth[o].amp_coefs[COEF_VEL] = 0; | ||
| // Other osc params. | ||
| synth[o].status = SYNTH_IS_ALGO_SOURCE; | ||
| synth[o].note_on_clock = total_samples; | ||
| AMY_UNSET(synth[o].note_off_clock); | ||
| partial_note_on(o); | ||
| } | ||
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| void interp_partials_note_on(uint16_t osc) { | ||
| // Choose the interp_partials patch. | ||
| const interp_partials_voice_t *partials_voice = &interp_partials_map[synth[osc].patch % NUM_INTERP_PARTIALS_PATCHES]; | ||
| float midi_note = synth[osc].midi_note; | ||
| float midi_vel = (int)roundf(synth[osc].velocity * 127.f); | ||
| // Clip | ||
| if (midi_vel < partials_voice->velocities[0]) midi_vel = partials_voice->velocities[0]; | ||
| if (midi_vel > partials_voice->velocities[partials_voice->num_velocities - 1]) midi_vel = partials_voice->velocities[partials_voice->num_velocities - 1]; | ||
| // Find the lower bound pitch/velocity indices. | ||
| uint8_t pitch_index = 0, vel_index = 0; | ||
| while(pitch_index < partials_voice->num_pitches - 1 | ||
| && partials_voice->pitches[pitch_index + 1] < midi_note) | ||
| ++pitch_index; | ||
| while(vel_index < partials_voice->num_velocities - 1 | ||
| && partials_voice->velocities[vel_index + 1] < midi_vel) | ||
| ++vel_index; | ||
| // Interp weights | ||
| float pitch_alpha = (midi_note - partials_voice->pitches[pitch_index]) | ||
| / (float)(partials_voice->pitches[pitch_index + 1] - partials_voice->pitches[pitch_index]); | ||
| float vel_alpha = (midi_vel - partials_voice->velocities[vel_index]) | ||
| / (float)(partials_voice->velocities[vel_index + 1] - partials_voice->velocities[vel_index]); | ||
| float harm_param[MAX_NUM_MAGNITUDES + 1]; // frequency + harmonic magnitudes. | ||
| int note_number = partials_voice->num_velocities * pitch_index + vel_index; | ||
| int num_harmonics = partials_voice->num_harmonics[note_number]; | ||
| // Interpolate the 4 notes. | ||
| int harmonic_base_index_pl_vl = | ||
| _harmonic_base_index_for_pitch_vel(pitch_index, vel_index, partials_voice); | ||
| float alpha_pl_vl = (1.f - pitch_alpha) * (1.f - vel_alpha); | ||
| int harmonic_base_index_pl_vh = | ||
| _harmonic_base_index_for_pitch_vel(pitch_index, vel_index + 1, partials_voice); | ||
| float alpha_pl_vh = (1.f - pitch_alpha) * (vel_alpha); | ||
| int harmonic_base_index_ph_vl = | ||
| _harmonic_base_index_for_pitch_vel(pitch_index + 1, vel_index, partials_voice); | ||
| float alpha_ph_vl = (pitch_alpha) * (1.f - vel_alpha); | ||
| int harmonic_base_index_ph_vh = | ||
| _harmonic_base_index_for_pitch_vel(pitch_index + 1, vel_index + 1, partials_voice); | ||
| float alpha_ph_vh = (pitch_alpha) * (vel_alpha); | ||
| //fprintf(stderr, "interp_partials@%u: osc %d note %d vel %d pitch_x %d vel_x %d numh %d harm_bi_ll %d pitch_a %.3f vel_a %.3f alphas %.2f %.2f %.2f %.2f\n", | ||
| // total_samples, osc, midi_note, midi_vel, pitch_index, vel_index, num_harmonics, harmonic_base_index_pl_vl, pitch_alpha, vel_alpha, | ||
| // alpha_pl_vl, alpha_pl_vh, alpha_ph_vl, alpha_ph_vh); | ||
| for (int h = 0; h < num_harmonics; ++h) { | ||
| for (int i = 0; i < MAX_NUM_MAGNITUDES + 1; ++i) harm_param[i] = 0; | ||
| _cumulate_scaled_harmonic_params(harm_param, harmonic_base_index_pl_vl + h, | ||
| alpha_pl_vl, partials_voice); | ||
| _cumulate_scaled_harmonic_params(harm_param, harmonic_base_index_pl_vh + h, | ||
| alpha_pl_vh, partials_voice); | ||
| _cumulate_scaled_harmonic_params(harm_param, harmonic_base_index_ph_vl + h, | ||
| alpha_ph_vl, partials_voice); | ||
| _cumulate_scaled_harmonic_params(harm_param, harmonic_base_index_ph_vh + h, | ||
| alpha_ph_vh, partials_voice); | ||
| //fprintf(stderr, "harm %d freq %.2f bps %.3f %.3f %.3f %.3f\n", h, harm_param[0], harm_param[1], harm_param[2], harm_param[3], harm_param[4]); | ||
| _osc_on_with_harm_param(osc + 1 + h, harm_param, partials_voice); | ||
| } | ||
| } | ||
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| void interp_partials_note_off(uint16_t osc) { | ||
| const interp_partials_voice_t *partials_voice = &interp_partials_map[synth[osc].patch % NUM_INTERP_PARTIALS_PATCHES]; | ||
| int num_oscs = partials_voice->num_harmonics[0]; // Assume first patch has the max #harmonics. | ||
| for(uint16_t i = osc + 1; i < osc + 1 + num_oscs; i++) { | ||
| uint16_t o = i % AMY_OSCS; | ||
| AMY_UNSET(synth[o].note_on_clock); | ||
| synth[o].note_off_clock = total_samples; | ||
| } | ||
| } |
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