diff options
Diffstat (limited to 'src/synth_engine.c')
| -rw-r--r-- | src/synth_engine.c | 332 |
1 files changed, 332 insertions, 0 deletions
diff --git a/src/synth_engine.c b/src/synth_engine.c new file mode 100644 index 0000000..57ec29b --- /dev/null +++ b/src/synth_engine.c @@ -0,0 +1,332 @@ +#include "synth_engine.h" +#include "lowpass.h" +#include "filter.h" + +float +adsr_amplitude(void *synthData, unsigned long long elapsed) +{ + synth_t *synth = (synth_t*)synthData; + + float dAmplitude = 0.0; + float dReleaseAmplitude = 0.0; + float dStartAmplitude = 1.0; + + float dLifeTime = (elapsed * (1.0 / (float)SAMPLE_RATE)); + + if (synth->n.noteOn != 0 && synth->n.noteOff == 0) { + if (dLifeTime <= synth->adsr.a) + dAmplitude = (dLifeTime / synth->adsr.a)*(dLifeTime / synth->adsr.a) * dStartAmplitude; + + if (dLifeTime > synth->adsr.a && dLifeTime <= ( synth->adsr.a + synth->adsr.d)) + dAmplitude = ((dLifeTime - synth->adsr.a) / synth->adsr.d) * (synth->adsr.s - dStartAmplitude) + dStartAmplitude; + + if (dLifeTime > (synth->adsr.a + synth->adsr.d)) + dAmplitude = synth->adsr.s; + } + else { // Note is off + if (dLifeTime <= synth->adsr.a) + dReleaseAmplitude = (dLifeTime / synth->adsr.a)*(dLifeTime / synth->adsr.a) * dStartAmplitude; + + if (dLifeTime > synth->adsr.a && dLifeTime <= (synth->adsr.a + synth->adsr.d)) + dReleaseAmplitude = ((dLifeTime - synth->adsr.a) / synth->adsr.d) * (synth->adsr.s - dStartAmplitude) + dStartAmplitude; + + if (dLifeTime > (synth->adsr.a + synth->adsr.d)) + dReleaseAmplitude = synth->adsr.s; + + dAmplitude = (((synth->n.noteOn + dLifeTime) - synth->n.noteOff) / synth->adsr.r) * (0.0 - dReleaseAmplitude) + dReleaseAmplitude; + + if (synth->adsr.r < 0) { + dAmplitude = synth->adsr.s; + } +} + // Amplitude should not be negative + if (dAmplitude <= 0.000) + dAmplitude = 0.0; + + return dAmplitude; +} + + +float +sin_sample(float amp, float freq, unsigned long long phase, unsigned int sample_rate) +{ + return amp * sinf(2.0 * M_PI * freq * ((float)phase / (float)sample_rate)); +} + +float +saw_sample(float amp, float freq, unsigned long long phase, unsigned int sample_rate) +{ + return amp * (0.17 * (1.0 - (2.0 * M_PI * freq * fmod((float)phase, (float)(sample_rate / (freq)))) / (float)sample_rate)); +} + +float +sawX_sample(float amp, float freq, float sm, unsigned long long phase, unsigned int sample_rate) +{ + float dOutput = 0.0; + for (float n = 1.0; n < sm; n++) + dOutput += (sinf(n * 2.0 * M_PI * freq * ((float)phase / (float)sample_rate))) / n; + return 0.5 * amp * dOutput; +} + +float +sqr_sample(float amp, float freq, float duty_cycle, unsigned long long phase, unsigned int sample_rate) +{ + if (duty_cycle < 0.0001 || duty_cycle > 0.9999) { + duty_cycle = 0.5; + } + + return (fmod((float)phase / (float)sample_rate, 1.0 / freq) < duty_cycle * (1.0 / freq)) ? amp : -amp; +} + +float +gen0(float f, unsigned long long phase, float x, unsigned int sample_rate) +{ + return sqr_sample(0.1, f, 0.3, phase, sample_rate) + + sqr_sample(0.1, f * 3.0 / 2.0 , 0.5, phase, sample_rate) + + saw_sample(0.3, f, phase, sample_rate) + + sin_sample(0.1, f, phase, sample_rate) + + sin_sample(0.1, f * 5, phase, sample_rate) + /* + sin_sample(0.1, freq * 50 * 1021, phase, sample_rate) */ + /* + sin_sample(0.1, freq * 50 * 3531021, phase, sample_rate) */ + + sin_sample(0.1, f * 7, phase, sample_rate); +} + +float +gen1(float f, unsigned long long phase, float x, unsigned int sample_rate) +{ + return sawX_sample(0.5, f, 5, phase, sample_rate) + + saw_sample(0.3, 2 * f / 5, phase, sample_rate) + + sin_sample(0.2, f * 5.0 / 7.0 , phase, sample_rate); +} + +float +gen2(float f, unsigned long long phase, float x, unsigned int sample_rate) +{ + return sin_sample(0.5, f * sqrt(2) , phase, sample_rate) + + sin_sample(0.5, f, phase, sample_rate); + + /* sawX_sample(1, synth->freq, 5, phase, sample_rate); */ +} + +float +gen3(float f, unsigned long long phase, float x, unsigned int sample_rate) +{ + return sawX_sample(0.7, f, 5, phase, sample_rate) + + sin_sample(0.3, 4.0/17.0*f, phase, sample_rate); + /* return sawX_sample(0.5, f * (1 + sqrt(5)) / 2, 5, phase, sample_rate) */ + /* + sin_sample(0.3, f * x, phase, sample_rate) */ + /* + sqr_sample(0.2, f * x, 0.2 * x * x, phase, sample_rate); */ +} + + + +/* 1d convolution */ +void +convole(float *signal, float *filter, size_t signal_size, size_t filter_size, float *out) { + for (size_t i = 0; i < filter_size + signal_size; i++) { + size_t kmin, kmax, k; + out[i] = 0; + /* find overlap */ + kmin = (i >= filter_size - 1) ? i - (filter_size - 1) : 0; + kmax = (i < signal_size - 1) ? i : signal_size - 1; + + /* Add the overlaping values */ + for (k = kmin; k <= kmax; k++) { + out[i] += signal[k] * filter[i - k]; + } + } +} + +void +low_pass_filter(float* signal, int length, float cutoff, float resonance, float* out) { + float c = 1.0f / tanf(M_PI * cutoff); // calculate filter constant + float a1 = 1.0f / (1.0f + resonance * c + c * c); // calculate filter coefficients + float a2 = 2.0f * a1; + float a3 = a1; + float b1 = 2.0f * (1.0f - c * c) * a1; + float b2 = (1.0f - resonance * c + c * c) * a1; + float prev_input = 0.0f, prev_output = 0.0f; // initialize previous input and output to zero + for (int i = 0; i < length; i++) { + float input = signal[i]; + float output = a1 * input + a2 * prev_input + a3 * prev_output - (i >= 1 ? b1 * out[i-1] : 0.0f) - (i >= 2 ? b2 * out[i-2] : 0.0f); + out[i] = output; + prev_input = input; + prev_output = output; + } +} + + +float +make_sample(unsigned long long phase, void *synthData, unsigned int sample_rate, int viz) +{ + synth_t *synth = (synth_t*)synthData; + float sample = 0; + + + int n = 1; + if (1 /* !synth->filter */) { + for (int i = 0; i < n; i++) { + sample += (1.0 / n) * synth->gen[synth->geni](synth->n.freq + synth->freq_offset, phase, synth->x, sample_rate); + } + + if (!viz && synth->filter) { + // ALLL THE FILTERS + LowPass_Update(synth->resonance, (adsr_amplitude(synth, synth->adsr.elapsed) + 0.1) * synth->cutoff + 1, sample_rate); + sample = LowPass_Filter(sample); + + update_bw_low_pass_filter(synth->fff, SAMPLE_RATE, (adsr_amplitude(synth, synth->adsr.elapsed) + 0.1) * synth->cutoff, synth->resonance); + sample = bw_low_pass(synth->fff, sample); + } + + sample = synth->gain * adsr_amplitude(synth, synth->adsr.elapsed) * + sample; //synth->gen[synth->geni](synth->n.freq + synth->freq_offset, phase, synth->x); + + if (synth->clamp && sample >= 1) sample = 0.99; + if (synth->clamp && sample <= -1) sample = -0.99; + } else { + // get sample array s[] + int samples = 30; + float s[samples]; + + if (synth->adsr.elapsed < samples) { + for (int i = 0; i < samples; i++) { + s[i] = synth->gain * adsr_amplitude(synth, i) * synth->gen[synth->geni](synth->n.freq + synth->freq_offset, i, synth->x, sample_rate); + } + } else { + for (int i = 0; i < samples; i++) { + s[i] = synth->gain * adsr_amplitude(synth, synth->adsr.elapsed - 50 + i) * synth->gen[synth->geni](synth->n.freq + synth->freq_offset, phase - 50 + i, synth->x, sample_rate); + } + } + + // process s[] + + + // return s[50] + } + + return sample; +} + +int +sound_gen(const void *inputBuffer, void *outputBuffer, + unsigned long framesPerBuffer, + const PaStreamCallbackTimeInfo* timeInfo, + PaStreamCallbackFlags statusFlags, + void *synthData) +{ + synth_t *synth = (synth_t*)synthData; + float *out = (float*)outputBuffer; + + (void) timeInfo; /* Prevent unused variable warnings. */ + (void) statusFlags; + (void) inputBuffer; + + if (1) { + float s; + for( unsigned long i=0; i<framesPerBuffer; i++ ) { + //get_portaudio_frame(outputBuffer, synth); + s = make_sample(synth->n.elapsed, synth, SAMPLE_RATE, 0); + *out++ = s; + *out++ = s; + synth->adsr.elapsed++; + synth->n.elapsed++; + if (!synth->multi) { + if (synth->n.elapsed >= (1.0 / synth->n.freq) * SAMPLE_RATE) synth->n.elapsed = 0; + } else { + + } + } + } else { + float s[FRAMES_PER_BUFFER * 5]; + + if (synth->adsr.elapsed < framesPerBuffer * 5) { + for (unsigned long long i = 0; i < framesPerBuffer * 5; i++) { + s[i] = make_sample(i, synth, SAMPLE_RATE, 0); + synth->adsr.elapsed++; + synth->n.elapsed++; + if (!synth->multi) { + if (synth->n.elapsed >= (1.0 / synth->n.freq) * SAMPLE_RATE) synth->n.elapsed = 0; + } else { + } + } + } else { + for (unsigned long long i = 0; i < framesPerBuffer * 5; i++) { + s[i] = make_sample(synth->n.elapsed - framesPerBuffer * 2 + i, synth, SAMPLE_RATE, 0); + synth->adsr.elapsed++; + synth->n.elapsed++; + if (!synth->multi) { + if (synth->n.elapsed >= (1.0 / synth->n.freq) * SAMPLE_RATE) synth->n.elapsed = 0; + } else { + } + } + } + + // filter + + // output + + if (synth->adsr.elapsed < framesPerBuffer * 5) { + for( unsigned long i=0; i<framesPerBuffer; i++ ) { + *out++ = s[i]; + *out++ = s[i]; + } + } else { + for( unsigned long i=0; i<framesPerBuffer; i++ ) { + *out++ = s[i + (2 * framesPerBuffer)]; + *out++ = s[i + (2 * framesPerBuffer)]; + } + } + synth->adsr.elapsed-= 4*framesPerBuffer; + + if (!synth->multi) { + for (int i = 0; i < framesPerBuffer * 4; i++) { + synth->n.elapsed--; + if (synth->n.elapsed == 0) synth->n.elapsed = (int)(SAMPLE_RATE / synth->n.freq); + } + } else { + synth->n.elapsed-= 4*framesPerBuffer; + } + } + + return paContinue; +} + +void +init_synth(synth_t * synth) +{ + synth->freq_offset = 0; + synth->gain = 1; + synth->x = 1; + + synth->n.freq = 0; + synth->n.noteOn = 0; + synth->n.noteOff = 1; + synth->n.key = 0; + synth->n.elapsed = 0; + + + synth->adsr.a = 0.001; + synth->adsr.d = 0.3; + synth->adsr.s = 0.7; + synth->adsr.r = 0.4; + synth->adsr.elapsed = 0; + + synth->octave = 3; + + synth->multi = 0; + synth->filter = 0; + synth->cutoff = 22000.0f; + synth->resonance = 1.0f; + synth->clamp = 0; + + synth->gen[0] = gen0; + synth->gen[1] = gen1; + synth->gen[2] = gen2; + synth->gen[3] = gen3; + synth->geni = 0; + + synth->viz.sample_rate_divider = 1; + + LowPass_Init(); + synth->fff = create_bw_low_pass_filter(2, SAMPLE_RATE, 400); +} |