1 /**
2 * OpenAL cross platform audio library
3 * Copyright (C) 2019 by Anis A. Hireche
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Library General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Library General Public License for more details.
13 *
14 * You should have received a copy of the GNU Library General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 * Or go to http://www.gnu.org/copyleft/lgpl.html
19 */
20
21 #include "config.h"
22
23 #include <cmath>
24 #include <cstdlib>
25 #include <algorithm>
26 #include <functional>
27
28 #include "alcmain.h"
29 #include "alcontext.h"
30 #include "alu.h"
31 #include "effectslot.h"
32 #include "math_defs.h"
33
34
35 namespace {
36
37 #define MAX_UPDATE_SAMPLES 256
38 #define NUM_FORMANTS 4
39 #define NUM_FILTERS 2
40 #define Q_FACTOR 5.0f
41
42 #define VOWEL_A_INDEX 0
43 #define VOWEL_B_INDEX 1
44
45 #define WAVEFORM_FRACBITS 24
46 #define WAVEFORM_FRACONE (1<<WAVEFORM_FRACBITS)
47 #define WAVEFORM_FRACMASK (WAVEFORM_FRACONE-1)
48
Sin(uint index)49 inline float Sin(uint index)
50 {
51 constexpr float scale{al::MathDefs<float>::Tau() / WAVEFORM_FRACONE};
52 return std::sin(static_cast<float>(index) * scale)*0.5f + 0.5f;
53 }
54
Saw(uint index)55 inline float Saw(uint index)
56 { return static_cast<float>(index) / float{WAVEFORM_FRACONE}; }
57
Triangle(uint index)58 inline float Triangle(uint index)
59 { return std::fabs(static_cast<float>(index)*(2.0f/WAVEFORM_FRACONE) - 1.0f); }
60
Half(uint)61 inline float Half(uint) { return 0.5f; }
62
63 template<float (&func)(uint)>
Oscillate(float * RESTRICT dst,uint index,const uint step,size_t todo)64 void Oscillate(float *RESTRICT dst, uint index, const uint step, size_t todo)
65 {
66 for(size_t i{0u};i < todo;i++)
67 {
68 index += step;
69 index &= WAVEFORM_FRACMASK;
70 dst[i] = func(index);
71 }
72 }
73
74 struct FormantFilter
75 {
76 float mCoeff{0.0f};
77 float mGain{1.0f};
78 float mS1{0.0f};
79 float mS2{0.0f};
80
81 FormantFilter() = default;
FormantFilter__anona695c3d90111::FormantFilter82 FormantFilter(float f0norm, float gain)
83 : mCoeff{std::tan(al::MathDefs<float>::Pi() * f0norm)}, mGain{gain}
84 { }
85
process__anona695c3d90111::FormantFilter86 inline void process(const float *samplesIn, float *samplesOut, const size_t numInput)
87 {
88 /* A state variable filter from a topology-preserving transform.
89 * Based on a talk given by Ivan Cohen: https://www.youtube.com/watch?v=esjHXGPyrhg
90 */
91 const float g{mCoeff};
92 const float gain{mGain};
93 const float h{1.0f / (1.0f + (g/Q_FACTOR) + (g*g))};
94 float s1{mS1};
95 float s2{mS2};
96
97 for(size_t i{0u};i < numInput;i++)
98 {
99 const float H{(samplesIn[i] - (1.0f/Q_FACTOR + g)*s1 - s2)*h};
100 const float B{g*H + s1};
101 const float L{g*B + s2};
102
103 s1 = g*H + B;
104 s2 = g*B + L;
105
106 // Apply peak and accumulate samples.
107 samplesOut[i] += B * gain;
108 }
109 mS1 = s1;
110 mS2 = s2;
111 }
112
clear__anona695c3d90111::FormantFilter113 inline void clear()
114 {
115 mS1 = 0.0f;
116 mS2 = 0.0f;
117 }
118 };
119
120
121 struct VmorpherState final : public EffectState {
122 struct {
123 /* Effect parameters */
124 FormantFilter Formants[NUM_FILTERS][NUM_FORMANTS];
125
126 /* Effect gains for each channel */
127 float CurrentGains[MAX_OUTPUT_CHANNELS]{};
128 float TargetGains[MAX_OUTPUT_CHANNELS]{};
129 } mChans[MaxAmbiChannels];
130
131 void (*mGetSamples)(float*RESTRICT, uint, const uint, size_t){};
132
133 uint mIndex{0};
134 uint mStep{1};
135
136 /* Effects buffers */
137 alignas(16) float mSampleBufferA[MAX_UPDATE_SAMPLES]{};
138 alignas(16) float mSampleBufferB[MAX_UPDATE_SAMPLES]{};
139 alignas(16) float mLfo[MAX_UPDATE_SAMPLES]{};
140
141 void deviceUpdate(const ALCdevice *device, const Buffer &buffer) override;
142 void update(const ALCcontext *context, const EffectSlot *slot, const EffectProps *props,
143 const EffectTarget target) override;
144 void process(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn,
145 const al::span<FloatBufferLine> samplesOut) override;
146
147 static std::array<FormantFilter,4> getFiltersByPhoneme(VMorpherPhenome phoneme,
148 float frequency, float pitch);
149
150 DEF_NEWDEL(VmorpherState)
151 };
152
getFiltersByPhoneme(VMorpherPhenome phoneme,float frequency,float pitch)153 std::array<FormantFilter,4> VmorpherState::getFiltersByPhoneme(VMorpherPhenome phoneme,
154 float frequency, float pitch)
155 {
156 /* Using soprano formant set of values to
157 * better match mid-range frequency space.
158 *
159 * See: https://www.classes.cs.uchicago.edu/archive/1999/spring/CS295/Computing_Resources/Csound/CsManual3.48b1.HTML/Appendices/table3.html
160 */
161 switch(phoneme)
162 {
163 case VMorpherPhenome::A:
164 return {{
165 {( 800 * pitch) / frequency, 1.000000f}, /* std::pow(10.0f, 0 / 20.0f); */
166 {(1150 * pitch) / frequency, 0.501187f}, /* std::pow(10.0f, -6 / 20.0f); */
167 {(2900 * pitch) / frequency, 0.025118f}, /* std::pow(10.0f, -32 / 20.0f); */
168 {(3900 * pitch) / frequency, 0.100000f} /* std::pow(10.0f, -20 / 20.0f); */
169 }};
170 case VMorpherPhenome::E:
171 return {{
172 {( 350 * pitch) / frequency, 1.000000f}, /* std::pow(10.0f, 0 / 20.0f); */
173 {(2000 * pitch) / frequency, 0.100000f}, /* std::pow(10.0f, -20 / 20.0f); */
174 {(2800 * pitch) / frequency, 0.177827f}, /* std::pow(10.0f, -15 / 20.0f); */
175 {(3600 * pitch) / frequency, 0.009999f} /* std::pow(10.0f, -40 / 20.0f); */
176 }};
177 case VMorpherPhenome::I:
178 return {{
179 {( 270 * pitch) / frequency, 1.000000f}, /* std::pow(10.0f, 0 / 20.0f); */
180 {(2140 * pitch) / frequency, 0.251188f}, /* std::pow(10.0f, -12 / 20.0f); */
181 {(2950 * pitch) / frequency, 0.050118f}, /* std::pow(10.0f, -26 / 20.0f); */
182 {(3900 * pitch) / frequency, 0.050118f} /* std::pow(10.0f, -26 / 20.0f); */
183 }};
184 case VMorpherPhenome::O:
185 return {{
186 {( 450 * pitch) / frequency, 1.000000f}, /* std::pow(10.0f, 0 / 20.0f); */
187 {( 800 * pitch) / frequency, 0.281838f}, /* std::pow(10.0f, -11 / 20.0f); */
188 {(2830 * pitch) / frequency, 0.079432f}, /* std::pow(10.0f, -22 / 20.0f); */
189 {(3800 * pitch) / frequency, 0.079432f} /* std::pow(10.0f, -22 / 20.0f); */
190 }};
191 case VMorpherPhenome::U:
192 return {{
193 {( 325 * pitch) / frequency, 1.000000f}, /* std::pow(10.0f, 0 / 20.0f); */
194 {( 700 * pitch) / frequency, 0.158489f}, /* std::pow(10.0f, -16 / 20.0f); */
195 {(2700 * pitch) / frequency, 0.017782f}, /* std::pow(10.0f, -35 / 20.0f); */
196 {(3800 * pitch) / frequency, 0.009999f} /* std::pow(10.0f, -40 / 20.0f); */
197 }};
198 default:
199 break;
200 }
201 return {};
202 }
203
204
deviceUpdate(const ALCdevice *,const Buffer &)205 void VmorpherState::deviceUpdate(const ALCdevice*, const Buffer&)
206 {
207 for(auto &e : mChans)
208 {
209 std::for_each(std::begin(e.Formants[VOWEL_A_INDEX]), std::end(e.Formants[VOWEL_A_INDEX]),
210 std::mem_fn(&FormantFilter::clear));
211 std::for_each(std::begin(e.Formants[VOWEL_B_INDEX]), std::end(e.Formants[VOWEL_B_INDEX]),
212 std::mem_fn(&FormantFilter::clear));
213 std::fill(std::begin(e.CurrentGains), std::end(e.CurrentGains), 0.0f);
214 }
215 }
216
update(const ALCcontext * context,const EffectSlot * slot,const EffectProps * props,const EffectTarget target)217 void VmorpherState::update(const ALCcontext *context, const EffectSlot *slot,
218 const EffectProps *props, const EffectTarget target)
219 {
220 const ALCdevice *device{context->mDevice.get()};
221 const float frequency{static_cast<float>(device->Frequency)};
222 const float step{props->Vmorpher.Rate / frequency};
223 mStep = fastf2u(clampf(step*WAVEFORM_FRACONE, 0.0f, float{WAVEFORM_FRACONE-1}));
224
225 if(mStep == 0)
226 mGetSamples = Oscillate<Half>;
227 else if(props->Vmorpher.Waveform == VMorpherWaveform::Sinusoid)
228 mGetSamples = Oscillate<Sin>;
229 else if(props->Vmorpher.Waveform == VMorpherWaveform::Triangle)
230 mGetSamples = Oscillate<Triangle>;
231 else /*if(props->Vmorpher.Waveform == VMorpherWaveform::Sawtooth)*/
232 mGetSamples = Oscillate<Saw>;
233
234 const float pitchA{std::pow(2.0f,
235 static_cast<float>(props->Vmorpher.PhonemeACoarseTuning) / 12.0f)};
236 const float pitchB{std::pow(2.0f,
237 static_cast<float>(props->Vmorpher.PhonemeBCoarseTuning) / 12.0f)};
238
239 auto vowelA = getFiltersByPhoneme(props->Vmorpher.PhonemeA, frequency, pitchA);
240 auto vowelB = getFiltersByPhoneme(props->Vmorpher.PhonemeB, frequency, pitchB);
241
242 /* Copy the filter coefficients to the input channels. */
243 for(size_t i{0u};i < slot->Wet.Buffer.size();++i)
244 {
245 std::copy(vowelA.begin(), vowelA.end(), std::begin(mChans[i].Formants[VOWEL_A_INDEX]));
246 std::copy(vowelB.begin(), vowelB.end(), std::begin(mChans[i].Formants[VOWEL_B_INDEX]));
247 }
248
249 mOutTarget = target.Main->Buffer;
250 auto set_gains = [slot,target](auto &chan, al::span<const float,MaxAmbiChannels> coeffs)
251 { ComputePanGains(target.Main, coeffs.data(), slot->Gain, chan.TargetGains); };
252 SetAmbiPanIdentity(std::begin(mChans), slot->Wet.Buffer.size(), set_gains);
253 }
254
process(const size_t samplesToDo,const al::span<const FloatBufferLine> samplesIn,const al::span<FloatBufferLine> samplesOut)255 void VmorpherState::process(const size_t samplesToDo, const al::span<const FloatBufferLine> samplesIn, const al::span<FloatBufferLine> samplesOut)
256 {
257 /* Following the EFX specification for a conformant implementation which describes
258 * the effect as a pair of 4-band formant filters blended together using an LFO.
259 */
260 for(size_t base{0u};base < samplesToDo;)
261 {
262 const size_t td{minz(MAX_UPDATE_SAMPLES, samplesToDo-base)};
263
264 mGetSamples(mLfo, mIndex, mStep, td);
265 mIndex += static_cast<uint>(mStep * td);
266 mIndex &= WAVEFORM_FRACMASK;
267
268 auto chandata = std::begin(mChans);
269 for(const auto &input : samplesIn)
270 {
271 auto& vowelA = chandata->Formants[VOWEL_A_INDEX];
272 auto& vowelB = chandata->Formants[VOWEL_B_INDEX];
273
274 /* Process first vowel. */
275 std::fill_n(std::begin(mSampleBufferA), td, 0.0f);
276 vowelA[0].process(&input[base], mSampleBufferA, td);
277 vowelA[1].process(&input[base], mSampleBufferA, td);
278 vowelA[2].process(&input[base], mSampleBufferA, td);
279 vowelA[3].process(&input[base], mSampleBufferA, td);
280
281 /* Process second vowel. */
282 std::fill_n(std::begin(mSampleBufferB), td, 0.0f);
283 vowelB[0].process(&input[base], mSampleBufferB, td);
284 vowelB[1].process(&input[base], mSampleBufferB, td);
285 vowelB[2].process(&input[base], mSampleBufferB, td);
286 vowelB[3].process(&input[base], mSampleBufferB, td);
287
288 alignas(16) float blended[MAX_UPDATE_SAMPLES];
289 for(size_t i{0u};i < td;i++)
290 blended[i] = lerp(mSampleBufferA[i], mSampleBufferB[i], mLfo[i]);
291
292 /* Now, mix the processed sound data to the output. */
293 MixSamples({blended, td}, samplesOut, chandata->CurrentGains, chandata->TargetGains,
294 samplesToDo-base, base);
295 ++chandata;
296 }
297
298 base += td;
299 }
300 }
301
302
303 struct VmorpherStateFactory final : public EffectStateFactory {
create__anona695c3d90111::VmorpherStateFactory304 al::intrusive_ptr<EffectState> create() override
305 { return al::intrusive_ptr<EffectState>{new VmorpherState{}}; }
306 };
307
308 } // namespace
309
VmorpherStateFactory_getFactory()310 EffectStateFactory *VmorpherStateFactory_getFactory()
311 {
312 static VmorpherStateFactory VmorpherFactory{};
313 return &VmorpherFactory;
314 }
315