| 1 | /* |
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| 2 | Copyright 2018 Google Inc. All Rights Reserved. |
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| 3 | |
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| 4 | Licensed under the Apache License, Version 2.0 (the "License"); |
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| 5 | you may not use this file except in compliance with the License. |
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| 6 | You may obtain a copy of the License at |
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| 7 | |
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| 8 | http://www.apache.org/licenses/LICENSE-2.0 |
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| 9 | |
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| 10 | Unless required by applicable law or agreed to in writing, software |
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| 11 | distributed under the License is distributed on an "AS-IS" BASIS, |
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| 12 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 13 | See the License for the specific language governing permissions and |
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| 14 | limitations under the License. |
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| 15 | */ |
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| 16 | |
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| 17 | #ifndef RESONANCE_AUDIO_DSP_OCCLUSION_CALCULATOR_H_ |
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| 18 | #define RESONANCE_AUDIO_DSP_OCCLUSION_CALCULATOR_H_ |
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| 19 | |
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| 20 | #include "base/spherical_angle.h" |
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| 21 | |
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| 22 | namespace vraudio { |
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| 23 | |
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| 24 | // Calculates directivity gain value for supplied source and listener |
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| 25 | // parameters. |
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| 26 | // |
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| 27 | // @param alpha Balance between dipole pattern and omnidirectional pattern for |
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| 28 | // source emission. By varying this value, differing directivity patterns |
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| 29 | // can be formed. Value in range [0, 1]. 2D visualization for several |
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| 30 | // values: http://goo.gl/GhKvoc. |
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| 31 | // @param order Order of directivity function. Higher values will result in |
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| 32 | // increased directivity. Value in range [1, +inf]. 2D visualization for |
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| 33 | // several orders: |
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| 34 | // http://goo.gl/sNrm1a. |
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| 35 | // @param spherical_angle Spherical angle of the listener relative to the |
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| 36 | // audio source which is being shaped. |
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| 37 | // @return Gain value in range [0, 1]. |
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| 38 | float CalculateDirectivity(float alpha, float order, |
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| 39 | const SphericalAngle& spherical_angle); |
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| 40 | |
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| 41 | // This function calculates a |MonoPoleFilter| coefficient based upon the |
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| 42 | // directivity and occlusion values. The coefficient calculation was designed |
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| 43 | // via empirical methods. |
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| 44 | // |
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| 45 | // @param directivity Gain value calculated based upon the directivity. |
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| 46 | // @param occlusion_intensity Gain value calculated based upon the degree of |
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| 47 | // occlusion. |
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| 48 | // @return Filter coefficient for a mono pole low pass filter. |
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| 49 | float CalculateOcclusionFilterCoefficient(float directivity, |
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| 50 | float occlusion_intensity); |
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| 51 | |
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| 52 | } // namespace vraudio |
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| 53 | |
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| 54 | #endif // RESONANCE_AUDIO_DSP_OCCLUSION_CALCULATOR_H_ |
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| 55 | |
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