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48 lines
1.4 KiB
C
48 lines
1.4 KiB
C
/*
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patest_pink.c
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generate Pink Noise using Gardner method.
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Optimization suggested by James McCartney uses a tree
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to select which random value to replace.
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x x x x x x x x x x x x x x x x
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x x x x x x x x
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x x x x
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x x
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x
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Tree is generated by counting trailing zeros in an increasing index.
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When the index is zero, no random number is selected.
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This program uses the Portable Audio library which is under development.
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For more information see: http://www.audiomulch.com/portaudio/
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Author: Phil Burk, http://www.softsynth.com
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Revision History:
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Copyleft 1999 Phil Burk - No rights reserved.
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*/
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#ifndef PINK_NOISE_H
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#define PINK_NOISE_H
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#define PINK_MAX_RANDOM_ROWS (30)
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#define PINK_RANDOM_BITS (24)
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#define PINK_RANDOM_SHIFT ((sizeof(long)*8)-PINK_RANDOM_BITS)
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typedef struct
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{
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long pink_rows[PINK_MAX_RANDOM_ROWS];
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long pink_running_sum; /* Used to optimize summing of generators. */
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int pink_index; /* Incremented each sample. */
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int pink_index_mask; /* Index wrapped by ANDing with this mask. */
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float pink_scalar; /* Used to scale within range of -1.0 to +1.0 */
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} pink_noise_t;
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void initialize_pink_noise( pink_noise_t *pink, int num_rows );
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float generate_pink_noise_sample( pink_noise_t *pink );
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#endif /* PINK_NOISE_H */
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