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82 lines
1.9 KiB
C
82 lines
1.9 KiB
C
#ifndef _MATHUTILS_H
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#define _MATHUTILS_H
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#include <cmath>
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#include <cstring>
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inline float sqr(float f) {return f*f;}
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inline float sqr_signed(float f) {return f<0 ? -f*f : f*f;}
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typedef unsigned short float16;
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// This ain't a 1.5.10 float16, it's a stupid hack format where we chop 16 bits off a float.
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// This choice is subject to change. Don't think I'm using this for anything at all now anyway.
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// DEPRECATED
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inline float16 FloatToFloat16(float x) {
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int ix;
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memcpy(&ix, &x, sizeof(float));
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return ix >> 16;
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}
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inline float Float16ToFloat(float16 ix) {
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float x;
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memcpy(&x, &ix, sizeof(float));
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return x;
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}
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#define PI 3.141592653589793f
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#ifndef M_PI
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#define M_PI 3.141592653589793f
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#endif
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// The stuff in this file is from all over the web, esp. dspmusic.org. I think it's all public domain.
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// In any case, very little of it is used anywhere at the moment.
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// Calculate pseudo-random 32 bit number based on linear congruential method.
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void SetSeed(unsigned int seed);
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unsigned int GenerateRandomNumber();
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inline float GenerateRandomFloat01() {
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return (float)((double)GenerateRandomNumber() / 0xFFFFFFFF);
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}
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inline float GenerateRandomSignedFloat() {
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return (float)((double)GenerateRandomNumber() / 0x80000000) - 1.0f;
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}
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inline float GaussRand()
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{
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float R1 = GenerateRandomFloat01();
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float R2 = GenerateRandomFloat01();
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float X = sqrtf(-2.0f * logf(R1)) * cosf(2.0f * PI * R2);
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if (X > 4.0f) X = 4.0f;
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if (X < -4.0f) X = -4.0f;
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return X;
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}
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// Accuracy unknown
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inline double atan_fast(double x) {
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return (x / (1.0 + 0.28 * (x * x)));
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}
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// linear -> dB conversion
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inline float lin2dB(float lin) {
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const float LOG_2_DB = 8.6858896380650365530225783783321f; // 20 / ln( 10 )
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return logf(lin) * LOG_2_DB;
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}
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// dB -> linear conversion
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inline float dB2lin(float dB) {
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const float DB_2_LOG = 0.11512925464970228420089957273422f; // ln( 10 ) / 20
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return expf(dB * DB_2_LOG);
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}
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// FPU control.
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void EnableFZ();
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void DisableFZ();
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#endif
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