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#include "LFOBase.h" |
#include "LFOBase.h" |
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// amplitue of 2nd harmonic (to approximate the triangular wave) |
// amplitue of 2nd harmonic (to approximate the triangular wave) |
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// TODO: this was just a quick head calculation, needs to be recalculated exactly (DFT) |
#define AMP2 0.11425509f |
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#define AMP2 0.1f |
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namespace LinuxSampler { |
namespace LinuxSampler { |
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real2 -= c2 * imag2; |
real2 -= c2 * imag2; |
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imag2 += c2 * real2; |
imag2 += c2 * real2; |
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if (RANGE == range_unsigned) |
if (RANGE == range_unsigned) |
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return (real1 + real2 * AMP2) * normalizer + normalizer; |
return (real1 + real2 * AMP2) * normalizer + offset; |
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else /* signed range */ |
else /* signed range */ |
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return (real1 + real2 * AMP2) * normalizer; |
return (real1 + real2 * AMP2) * normalizer; |
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} |
} |
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*/ |
*/ |
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inline void update(const uint16_t& ExtControlValue) { |
inline void update(const uint16_t& ExtControlValue) { |
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const float max = this->InternalDepth + ExtControlValue * this->ExtControlDepthCoeff; |
const float max = this->InternalDepth + ExtControlValue * this->ExtControlDepthCoeff; |
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if (RANGE == range_unsigned) |
if (RANGE == range_unsigned) { |
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const float harmonicCompensation = 1.0f + AMP2; // to compensate the compensation ;) (see trigger()) |
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normalizer = max * 0.5f; |
normalizer = max * 0.5f; |
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else /* signed range */ |
offset = normalizer * harmonicCompensation; |
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} else { // signed range |
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normalizer = max; |
normalizer = max; |
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} |
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} |
} |
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/** |
/** |
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* @param ExtControlDepth - defines how strong the external MIDI |
* @param ExtControlDepth - defines how strong the external MIDI |
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* controller has influence on the |
* controller has influence on the |
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* oscillator amplitude |
* oscillator amplitude |
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* @param FlipPhase - inverts the oscillator wave |
* @param FlipPhase - inverts the oscillator wave against |
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* a horizontal axis |
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* @param SampleRate - current sample rate of the engines |
* @param SampleRate - current sample rate of the engines |
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* audio output signal |
* audio output signal |
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*/ |
*/ |
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void trigger(float Frequency, start_level_t StartLevel, uint16_t InternalDepth, uint16_t ExtControlDepth, bool FlipPhase, unsigned int SampleRate) { |
void trigger(float Frequency, start_level_t StartLevel, uint16_t InternalDepth, uint16_t ExtControlDepth, bool FlipPhase, unsigned int SampleRate) { |
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this->InternalDepth = (InternalDepth / 1200.0f) * this->Max; |
const float harmonicCompensation = 1.0f + AMP2; // to compensate the 2nd harmonic's amplitude overhead |
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this->ExtControlDepthCoeff = (((float) ExtControlDepth / 1200.0f) / 127.0f) * this->Max; |
this->InternalDepth = (InternalDepth / 1200.0f) * this->Max / harmonicCompensation; |
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this->ExtControlDepthCoeff = (((float) ExtControlDepth / 1200.0f) / 127.0f) * this->Max / harmonicCompensation; |
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c1 = 2.0f * M_PI * Frequency / (float) SampleRate; |
c1 = 2.0f * M_PI * Frequency / (float) SampleRate; |
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c2 = 2.0f * M_PI * Frequency / (float) SampleRate * 3.0f; |
c2 = 2.0f * M_PI * Frequency / (float) SampleRate * 3.0f; |
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float phi; // phase displacement |
double phi; // phase displacement |
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switch (StartLevel) { |
switch (StartLevel) { |
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case start_level_max: |
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phi = 0.0f; // 0° |
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break; |
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case start_level_mid: |
case start_level_mid: |
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phi = (FlipPhase) ? 3.0f * M_PI : M_PI; // 270° or 90° |
//FIXME: direct jumping to 90° and 270° doesn't work out due to numeric accuracy problems (causes wave deformation) |
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//phi = (FlipPhase) ? 0.5 * M_PI : 1.5 * M_PI; // 90° or 270° |
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//break; |
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case start_level_max: |
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phi = (FlipPhase) ? M_PI : 0.0; // 180° or 0° |
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break; |
break; |
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case start_level_min: |
case start_level_min: |
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phi = 2.0f * M_PI; // 180° |
phi = (FlipPhase) ? 0.0 : M_PI; // 0° or 180° |
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break; |
break; |
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} |
} |
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real1 = real2 = cos(phi); |
real1 = real2 = cos(phi); |
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float real2; |
float real2; |
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float imag2; |
float imag2; |
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float normalizer; |
float normalizer; |
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float offset; |
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}; |
}; |
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} // namespace LinuxSampler |
} // namespace LinuxSampler |