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Diffstat (limited to 'indra/llmath/llmath.h')
-rw-r--r-- | indra/llmath/llmath.h | 1018 |
1 files changed, 509 insertions, 509 deletions
diff --git a/indra/llmath/llmath.h b/indra/llmath/llmath.h index 742bbc4751..e572381b1a 100644 --- a/indra/llmath/llmath.h +++ b/indra/llmath/llmath.h @@ -1,509 +1,509 @@ -/**
- * @file llmath.h
- * @brief Useful math constants and macros.
- *
- * $LicenseInfo:firstyear=2000&license=viewergpl$
- *
- * Copyright (c) 2000-2009, Linden Research, Inc.
- *
- * Second Life Viewer Source Code
- * The source code in this file ("Source Code") is provided by Linden Lab
- * to you under the terms of the GNU General Public License, version 2.0
- * ("GPL"), unless you have obtained a separate licensing agreement
- * ("Other License"), formally executed by you and Linden Lab. Terms of
- * the GPL can be found in doc/GPL-license.txt in this distribution, or
- * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
- *
- * There are special exceptions to the terms and conditions of the GPL as
- * it is applied to this Source Code. View the full text of the exception
- * in the file doc/FLOSS-exception.txt in this software distribution, or
- * online at
- * http://secondlifegrid.net/programs/open_source/licensing/flossexception
- *
- * By copying, modifying or distributing this software, you acknowledge
- * that you have read and understood your obligations described above,
- * and agree to abide by those obligations.
- *
- * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
- * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
- * COMPLETENESS OR PERFORMANCE.
- * $/LicenseInfo$
- */
-
-#ifndef LLMATH_H
-#define LLMATH_H
-
-#include <cmath>
-#include <cstdlib>
-#include "lldefs.h"
-//#include "llstl.h" // *TODO: Remove when LLString is gone
-//#include "llstring.h" // *TODO: Remove when LLString is gone
-// lltut.h uses is_approx_equal_fraction(). This was moved to its own header
-// file in llcommon so we can use lltut.h for llcommon tests without making
-// llcommon depend on llmath.
-#include "is_approx_equal_fraction.h"
-
-// work around for Windows & older gcc non-standard function names.
-#if LL_WINDOWS
-#include <float.h>
-#define llisnan(val) _isnan(val)
-#define llfinite(val) _finite(val)
-#elif (LL_LINUX && __GNUC__ <= 2)
-#define llisnan(val) isnan(val)
-#define llfinite(val) isfinite(val)
-#elif LL_SOLARIS
-#define llisnan(val) isnan(val)
-#define llfinite(val) (val <= std::numeric_limits<double>::max())
-#else
-#define llisnan(val) std::isnan(val)
-#define llfinite(val) std::isfinite(val)
-#endif
-
-// Single Precision Floating Point Routines
-// (There used to be more defined here, but they appeared to be redundant and
-// were breaking some other includes. Removed by Falcon, reviewed by Andrew, 11/25/09)
-/*#ifndef tanf
-#define tanf(x) ((F32)tan((F64)(x)))
-#endif*/
-
-const F32 GRAVITY = -9.8f;
-
-// mathematical constants
-const F32 F_PI = 3.1415926535897932384626433832795f;
-const F32 F_TWO_PI = 6.283185307179586476925286766559f;
-const F32 F_PI_BY_TWO = 1.5707963267948966192313216916398f;
-const F32 F_SQRT_TWO_PI = 2.506628274631000502415765284811f;
-const F32 F_E = 2.71828182845904523536f;
-const F32 F_SQRT2 = 1.4142135623730950488016887242097f;
-const F32 F_SQRT3 = 1.73205080756888288657986402541f;
-const F32 OO_SQRT2 = 0.7071067811865475244008443621049f;
-const F32 DEG_TO_RAD = 0.017453292519943295769236907684886f;
-const F32 RAD_TO_DEG = 57.295779513082320876798154814105f;
-const F32 F_APPROXIMATELY_ZERO = 0.00001f;
-const F32 F_LN2 = 0.69314718056f;
-const F32 OO_LN2 = 1.4426950408889634073599246810019f;
-
-const F32 F_ALMOST_ZERO = 0.0001f;
-const F32 F_ALMOST_ONE = 1.0f - F_ALMOST_ZERO;
-
-// BUG: Eliminate in favor of F_APPROXIMATELY_ZERO above?
-const F32 FP_MAG_THRESHOLD = 0.0000001f;
-
-// TODO: Replace with logic like is_approx_equal
-inline BOOL is_approx_zero( F32 f ) { return (-F_APPROXIMATELY_ZERO < f) && (f < F_APPROXIMATELY_ZERO); }
-
-// These functions work by interpreting sign+exp+mantissa as an unsigned
-// integer.
-// For example:
-// x = <sign>1 <exponent>00000010 <mantissa>00000000000000000000000
-// y = <sign>1 <exponent>00000001 <mantissa>11111111111111111111111
-//
-// interpreted as ints =
-// x = 10000001000000000000000000000000
-// y = 10000000111111111111111111111111
-// which is clearly a different of 1 in the least significant bit
-// Values with the same exponent can be trivially shown to work.
-//
-// WARNING: Denormals of opposite sign do not work
-// x = <sign>1 <exponent>00000000 <mantissa>00000000000000000000001
-// y = <sign>0 <exponent>00000000 <mantissa>00000000000000000000001
-// Although these values differ by 2 in the LSB, the sign bit makes
-// the int comparison fail.
-//
-// WARNING: NaNs can compare equal
-// There is no special treatment of exceptional values like NaNs
-//
-// WARNING: Infinity is comparable with F32_MAX and negative
-// infinity is comparable with F32_MIN
-
-inline BOOL is_approx_equal(F32 x, F32 y)
-{
- const S32 COMPARE_MANTISSA_UP_TO_BIT = 0x02;
- return (std::abs((S32) ((U32&)x - (U32&)y) ) < COMPARE_MANTISSA_UP_TO_BIT);
-}
-
-inline BOOL is_approx_equal(F64 x, F64 y)
-{
- const S64 COMPARE_MANTISSA_UP_TO_BIT = 0x02;
- return (std::abs((S32) ((U64&)x - (U64&)y) ) < COMPARE_MANTISSA_UP_TO_BIT);
-}
-
-inline S32 llabs(const S32 a)
-{
- return S32(std::labs(a));
-}
-
-inline F32 llabs(const F32 a)
-{
- return F32(std::fabs(a));
-}
-
-inline F64 llabs(const F64 a)
-{
- return F64(std::fabs(a));
-}
-
-inline S32 lltrunc( F32 f )
-{
-#if LL_WINDOWS && !defined( __INTEL_COMPILER )
- // Avoids changing the floating point control word.
- // Add or subtract 0.5 - epsilon and then round
- const static U32 zpfp[] = { 0xBEFFFFFF, 0x3EFFFFFF };
- S32 result;
- __asm {
- fld f
- mov eax, f
- shr eax, 29
- and eax, 4
- fadd dword ptr [zpfp + eax]
- fistp result
- }
- return result;
-#else
- return (S32)f;
-#endif
-}
-
-inline S32 lltrunc( F64 f )
-{
- return (S32)f;
-}
-
-inline S32 llfloor( F32 f )
-{
-#if LL_WINDOWS && !defined( __INTEL_COMPILER )
- // Avoids changing the floating point control word.
- // Accurate (unlike Stereopsis version) for all values between S32_MIN and S32_MAX and slightly faster than Stereopsis version.
- // Add -(0.5 - epsilon) and then round
- const U32 zpfp = 0xBEFFFFFF;
- S32 result;
- __asm {
- fld f
- fadd dword ptr [zpfp]
- fistp result
- }
- return result;
-#else
- return (S32)floor(f);
-#endif
-}
-
-
-inline S32 llceil( F32 f )
-{
- // This could probably be optimized, but this works.
- return (S32)ceil(f);
-}
-
-
-#ifndef BOGUS_ROUND
-// Use this round. Does an arithmetic round (0.5 always rounds up)
-inline S32 llround(const F32 val)
-{
- return llfloor(val + 0.5f);
-}
-
-#else // BOGUS_ROUND
-// Old llround implementation - does banker's round (toward nearest even in the case of a 0.5.
-// Not using this because we don't have a consistent implementation on both platforms, use
-// llfloor(val + 0.5f), which is consistent on all platforms.
-inline S32 llround(const F32 val)
-{
- #if LL_WINDOWS
- // Note: assumes that the floating point control word is set to rounding mode (the default)
- S32 ret_val;
- _asm fld val
- _asm fistp ret_val;
- return ret_val;
- #elif LL_LINUX
- // Note: assumes that the floating point control word is set
- // to rounding mode (the default)
- S32 ret_val;
- __asm__ __volatile__( "flds %1 \n\t"
- "fistpl %0 \n\t"
- : "=m" (ret_val)
- : "m" (val) );
- return ret_val;
- #else
- return llfloor(val + 0.5f);
- #endif
-}
-
-// A fast arithmentic round on intel, from Laurent de Soras http://ldesoras.free.fr
-inline int round_int(double x)
-{
- const float round_to_nearest = 0.5f;
- int i;
- __asm
- {
- fld x
- fadd st, st (0)
- fadd round_to_nearest
- fistp i
- sar i, 1
- }
- return (i);
-}
-#endif // BOGUS_ROUND
-
-inline F32 llround( F32 val, F32 nearest )
-{
- return F32(floor(val * (1.0f / nearest) + 0.5f)) * nearest;
-}
-
-inline F64 llround( F64 val, F64 nearest )
-{
- return F64(floor(val * (1.0 / nearest) + 0.5)) * nearest;
-}
-
-// these provide minimum peak error
-//
-// avg error = -0.013049
-// peak error = -31.4 dB
-// RMS error = -28.1 dB
-
-const F32 FAST_MAG_ALPHA = 0.960433870103f;
-const F32 FAST_MAG_BETA = 0.397824734759f;
-
-// these provide minimum RMS error
-//
-// avg error = 0.000003
-// peak error = -32.6 dB
-// RMS error = -25.7 dB
-//
-//const F32 FAST_MAG_ALPHA = 0.948059448969f;
-//const F32 FAST_MAG_BETA = 0.392699081699f;
-
-inline F32 fastMagnitude(F32 a, F32 b)
-{
- a = (a > 0) ? a : -a;
- b = (b > 0) ? b : -b;
- return(FAST_MAG_ALPHA * llmax(a,b) + FAST_MAG_BETA * llmin(a,b));
-}
-
-
-
-////////////////////
-//
-// Fast F32/S32 conversions
-//
-// Culled from www.stereopsis.com/FPU.html
-
-const F64 LL_DOUBLE_TO_FIX_MAGIC = 68719476736.0*1.5; //2^36 * 1.5, (52-_shiftamt=36) uses limited precisicion to floor
-const S32 LL_SHIFT_AMOUNT = 16; //16.16 fixed point representation,
-
-// Endian dependent code
-#ifdef LL_LITTLE_ENDIAN
- #define LL_EXP_INDEX 1
- #define LL_MAN_INDEX 0
-#else
- #define LL_EXP_INDEX 0
- #define LL_MAN_INDEX 1
-#endif
-
-/* Deprecated: use llround(), lltrunc(), or llfloor() instead
-// ================================================================================================
-// Real2Int
-// ================================================================================================
-inline S32 F64toS32(F64 val)
-{
- val = val + LL_DOUBLE_TO_FIX_MAGIC;
- return ((S32*)&val)[LL_MAN_INDEX] >> LL_SHIFT_AMOUNT;
-}
-
-// ================================================================================================
-// Real2Int
-// ================================================================================================
-inline S32 F32toS32(F32 val)
-{
- return F64toS32 ((F64)val);
-}
-*/
-
-////////////////////////////////////////////////
-//
-// Fast exp and log
-//
-
-// Implementation of fast exp() approximation (from a paper by Nicol N. Schraudolph
-// http://www.inf.ethz.ch/~schraudo/pubs/exp.pdf
-static union
-{
- double d;
- struct
- {
-#ifdef LL_LITTLE_ENDIAN
- S32 j, i;
-#else
- S32 i, j;
-#endif
- } n;
-} LLECO; // not sure what the name means
-
-#define LL_EXP_A (1048576 * OO_LN2) // use 1512775 for integer
-#define LL_EXP_C (60801) // this value of C good for -4 < y < 4
-
-#define LL_FAST_EXP(y) (LLECO.n.i = llround(F32(LL_EXP_A*(y))) + (1072693248 - LL_EXP_C), LLECO.d)
-
-
-
-inline F32 llfastpow(const F32 x, const F32 y)
-{
- return (F32)(LL_FAST_EXP(y * log(x)));
-}
-
-
-inline F32 snap_to_sig_figs(F32 foo, S32 sig_figs)
-{
- // compute the power of ten
- F32 bar = 1.f;
- for (S32 i = 0; i < sig_figs; i++)
- {
- bar *= 10.f;
- }
-
- //F32 new_foo = (F32)llround(foo * bar);
- // the llround() implementation sucks. Don't us it.
-
- F32 sign = (foo > 0.f) ? 1.f : -1.f;
- F32 new_foo = F32( S64(foo * bar + sign * 0.5f));
- new_foo /= bar;
-
- return new_foo;
-}
-
-inline F32 lerp(F32 a, F32 b, F32 u)
-{
- return a + ((b - a) * u);
-}
-
-inline F32 lerp2d(F32 x00, F32 x01, F32 x10, F32 x11, F32 u, F32 v)
-{
- F32 a = x00 + (x01-x00)*u;
- F32 b = x10 + (x11-x10)*u;
- F32 r = a + (b-a)*v;
- return r;
-}
-
-inline F32 ramp(F32 x, F32 a, F32 b)
-{
- return (a == b) ? 0.0f : ((a - x) / (a - b));
-}
-
-inline F32 rescale(F32 x, F32 x1, F32 x2, F32 y1, F32 y2)
-{
- return lerp(y1, y2, ramp(x, x1, x2));
-}
-
-inline F32 clamp_rescale(F32 x, F32 x1, F32 x2, F32 y1, F32 y2)
-{
- if (y1 < y2)
- {
- return llclamp(rescale(x,x1,x2,y1,y2),y1,y2);
- }
- else
- {
- return llclamp(rescale(x,x1,x2,y1,y2),y2,y1);
- }
-}
-
-
-inline F32 cubic_step( F32 x, F32 x0, F32 x1, F32 s0, F32 s1 )
-{
- if (x <= x0)
- return s0;
-
- if (x >= x1)
- return s1;
-
- F32 f = (x - x0) / (x1 - x0);
-
- return s0 + (s1 - s0) * (f * f) * (3.0f - 2.0f * f);
-}
-
-inline F32 cubic_step( F32 x )
-{
- x = llclampf(x);
-
- return (x * x) * (3.0f - 2.0f * x);
-}
-
-inline F32 quadratic_step( F32 x, F32 x0, F32 x1, F32 s0, F32 s1 )
-{
- if (x <= x0)
- return s0;
-
- if (x >= x1)
- return s1;
-
- F32 f = (x - x0) / (x1 - x0);
- F32 f_squared = f * f;
-
- return (s0 * (1.f - f_squared)) + ((s1 - s0) * f_squared);
-}
-
-inline F32 llsimple_angle(F32 angle)
-{
- while(angle <= -F_PI)
- angle += F_TWO_PI;
- while(angle > F_PI)
- angle -= F_TWO_PI;
- return angle;
-}
-
-//SDK - Renamed this to get_lower_power_two, since this is what this actually does.
-inline U32 get_lower_power_two(U32 val, U32 max_power_two)
-{
- if(!max_power_two)
- {
- max_power_two = 1 << 31 ;
- }
- if(max_power_two & (max_power_two - 1))
- {
- return 0 ;
- }
-
- for(; val < max_power_two ; max_power_two >>= 1) ;
-
- return max_power_two ;
-}
-
-// calculate next highest power of two, limited by max_power_two
-// This is taken from a brilliant little code snipped on http://acius2.blogspot.com/2007/11/calculating-next-power-of-2.html
-// Basically we convert the binary to a solid string of 1's with the same
-// number of digits, then add one. We subtract 1 initially to handle
-// the case where the number passed in is actually a power of two.
-// WARNING: this only works with 32 bit ints.
-inline U32 get_next_power_two(U32 val, U32 max_power_two)
-{
- if(!max_power_two)
- {
- max_power_two = 1 << 31 ;
- }
-
- if(val >= max_power_two)
- {
- return max_power_two;
- }
-
- val--;
- val = (val >> 1) | val;
- val = (val >> 2) | val;
- val = (val >> 4) | val;
- val = (val >> 8) | val;
- val = (val >> 16) | val;
- val++;
-
- return val;
-}
-
-//get the gaussian value given the linear distance from axis x and guassian value o
-inline F32 llgaussian(F32 x, F32 o)
-{
- return 1.f/(F_SQRT_TWO_PI*o)*powf(F_E, -(x*x)/(2*o*o));
-}
-
-// Include simd math header
-#include "llsimdmath.h"
-
-#endif
+/** + * @file llmath.h + * @brief Useful math constants and macros. + * + * $LicenseInfo:firstyear=2000&license=viewergpl$ + * + * Copyright (c) 2000-2009, Linden Research, Inc. + * + * Second Life Viewer Source Code + * The source code in this file ("Source Code") is provided by Linden Lab + * to you under the terms of the GNU General Public License, version 2.0 + * ("GPL"), unless you have obtained a separate licensing agreement + * ("Other License"), formally executed by you and Linden Lab. Terms of + * the GPL can be found in doc/GPL-license.txt in this distribution, or + * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2 + * + * There are special exceptions to the terms and conditions of the GPL as + * it is applied to this Source Code. View the full text of the exception + * in the file doc/FLOSS-exception.txt in this software distribution, or + * online at + * http://secondlifegrid.net/programs/open_source/licensing/flossexception + * + * By copying, modifying or distributing this software, you acknowledge + * that you have read and understood your obligations described above, + * and agree to abide by those obligations. + * + * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO + * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY, + * COMPLETENESS OR PERFORMANCE. + * $/LicenseInfo$ + */ + +#ifndef LLMATH_H +#define LLMATH_H + +#include <cmath> +#include <cstdlib> +#include "lldefs.h" +//#include "llstl.h" // *TODO: Remove when LLString is gone +//#include "llstring.h" // *TODO: Remove when LLString is gone +// lltut.h uses is_approx_equal_fraction(). This was moved to its own header +// file in llcommon so we can use lltut.h for llcommon tests without making +// llcommon depend on llmath. +#include "is_approx_equal_fraction.h" + +// work around for Windows & older gcc non-standard function names. +#if LL_WINDOWS +#include <float.h> +#define llisnan(val) _isnan(val) +#define llfinite(val) _finite(val) +#elif (LL_LINUX && __GNUC__ <= 2) +#define llisnan(val) isnan(val) +#define llfinite(val) isfinite(val) +#elif LL_SOLARIS +#define llisnan(val) isnan(val) +#define llfinite(val) (val <= std::numeric_limits<double>::max()) +#else +#define llisnan(val) std::isnan(val) +#define llfinite(val) std::isfinite(val) +#endif + +// Single Precision Floating Point Routines +// (There used to be more defined here, but they appeared to be redundant and +// were breaking some other includes. Removed by Falcon, reviewed by Andrew, 11/25/09) +/*#ifndef tanf +#define tanf(x) ((F32)tan((F64)(x))) +#endif*/ + +const F32 GRAVITY = -9.8f; + +// mathematical constants +const F32 F_PI = 3.1415926535897932384626433832795f; +const F32 F_TWO_PI = 6.283185307179586476925286766559f; +const F32 F_PI_BY_TWO = 1.5707963267948966192313216916398f; +const F32 F_SQRT_TWO_PI = 2.506628274631000502415765284811f; +const F32 F_E = 2.71828182845904523536f; +const F32 F_SQRT2 = 1.4142135623730950488016887242097f; +const F32 F_SQRT3 = 1.73205080756888288657986402541f; +const F32 OO_SQRT2 = 0.7071067811865475244008443621049f; +const F32 DEG_TO_RAD = 0.017453292519943295769236907684886f; +const F32 RAD_TO_DEG = 57.295779513082320876798154814105f; +const F32 F_APPROXIMATELY_ZERO = 0.00001f; +const F32 F_LN2 = 0.69314718056f; +const F32 OO_LN2 = 1.4426950408889634073599246810019f; + +const F32 F_ALMOST_ZERO = 0.0001f; +const F32 F_ALMOST_ONE = 1.0f - F_ALMOST_ZERO; + +// BUG: Eliminate in favor of F_APPROXIMATELY_ZERO above? +const F32 FP_MAG_THRESHOLD = 0.0000001f; + +// TODO: Replace with logic like is_approx_equal +inline BOOL is_approx_zero( F32 f ) { return (-F_APPROXIMATELY_ZERO < f) && (f < F_APPROXIMATELY_ZERO); } + +// These functions work by interpreting sign+exp+mantissa as an unsigned +// integer. +// For example: +// x = <sign>1 <exponent>00000010 <mantissa>00000000000000000000000 +// y = <sign>1 <exponent>00000001 <mantissa>11111111111111111111111 +// +// interpreted as ints = +// x = 10000001000000000000000000000000 +// y = 10000000111111111111111111111111 +// which is clearly a different of 1 in the least significant bit +// Values with the same exponent can be trivially shown to work. +// +// WARNING: Denormals of opposite sign do not work +// x = <sign>1 <exponent>00000000 <mantissa>00000000000000000000001 +// y = <sign>0 <exponent>00000000 <mantissa>00000000000000000000001 +// Although these values differ by 2 in the LSB, the sign bit makes +// the int comparison fail. +// +// WARNING: NaNs can compare equal +// There is no special treatment of exceptional values like NaNs +// +// WARNING: Infinity is comparable with F32_MAX and negative +// infinity is comparable with F32_MIN + +inline BOOL is_approx_equal(F32 x, F32 y) +{ + const S32 COMPARE_MANTISSA_UP_TO_BIT = 0x02; + return (std::abs((S32) ((U32&)x - (U32&)y) ) < COMPARE_MANTISSA_UP_TO_BIT); +} + +inline BOOL is_approx_equal(F64 x, F64 y) +{ + const S64 COMPARE_MANTISSA_UP_TO_BIT = 0x02; + return (std::abs((S32) ((U64&)x - (U64&)y) ) < COMPARE_MANTISSA_UP_TO_BIT); +} + +inline S32 llabs(const S32 a) +{ + return S32(std::labs(a)); +} + +inline F32 llabs(const F32 a) +{ + return F32(std::fabs(a)); +} + +inline F64 llabs(const F64 a) +{ + return F64(std::fabs(a)); +} + +inline S32 lltrunc( F32 f ) +{ +#if LL_WINDOWS && !defined( __INTEL_COMPILER ) + // Avoids changing the floating point control word. + // Add or subtract 0.5 - epsilon and then round + const static U32 zpfp[] = { 0xBEFFFFFF, 0x3EFFFFFF }; + S32 result; + __asm { + fld f + mov eax, f + shr eax, 29 + and eax, 4 + fadd dword ptr [zpfp + eax] + fistp result + } + return result; +#else + return (S32)f; +#endif +} + +inline S32 lltrunc( F64 f ) +{ + return (S32)f; +} + +inline S32 llfloor( F32 f ) +{ +#if LL_WINDOWS && !defined( __INTEL_COMPILER ) + // Avoids changing the floating point control word. + // Accurate (unlike Stereopsis version) for all values between S32_MIN and S32_MAX and slightly faster than Stereopsis version. + // Add -(0.5 - epsilon) and then round + const U32 zpfp = 0xBEFFFFFF; + S32 result; + __asm { + fld f + fadd dword ptr [zpfp] + fistp result + } + return result; +#else + return (S32)floor(f); +#endif +} + + +inline S32 llceil( F32 f ) +{ + // This could probably be optimized, but this works. + return (S32)ceil(f); +} + + +#ifndef BOGUS_ROUND +// Use this round. Does an arithmetic round (0.5 always rounds up) +inline S32 llround(const F32 val) +{ + return llfloor(val + 0.5f); +} + +#else // BOGUS_ROUND +// Old llround implementation - does banker's round (toward nearest even in the case of a 0.5. +// Not using this because we don't have a consistent implementation on both platforms, use +// llfloor(val + 0.5f), which is consistent on all platforms. +inline S32 llround(const F32 val) +{ + #if LL_WINDOWS + // Note: assumes that the floating point control word is set to rounding mode (the default) + S32 ret_val; + _asm fld val + _asm fistp ret_val; + return ret_val; + #elif LL_LINUX + // Note: assumes that the floating point control word is set + // to rounding mode (the default) + S32 ret_val; + __asm__ __volatile__( "flds %1 \n\t" + "fistpl %0 \n\t" + : "=m" (ret_val) + : "m" (val) ); + return ret_val; + #else + return llfloor(val + 0.5f); + #endif +} + +// A fast arithmentic round on intel, from Laurent de Soras http://ldesoras.free.fr +inline int round_int(double x) +{ + const float round_to_nearest = 0.5f; + int i; + __asm + { + fld x + fadd st, st (0) + fadd round_to_nearest + fistp i + sar i, 1 + } + return (i); +} +#endif // BOGUS_ROUND + +inline F32 llround( F32 val, F32 nearest ) +{ + return F32(floor(val * (1.0f / nearest) + 0.5f)) * nearest; +} + +inline F64 llround( F64 val, F64 nearest ) +{ + return F64(floor(val * (1.0 / nearest) + 0.5)) * nearest; +} + +// these provide minimum peak error +// +// avg error = -0.013049 +// peak error = -31.4 dB +// RMS error = -28.1 dB + +const F32 FAST_MAG_ALPHA = 0.960433870103f; +const F32 FAST_MAG_BETA = 0.397824734759f; + +// these provide minimum RMS error +// +// avg error = 0.000003 +// peak error = -32.6 dB +// RMS error = -25.7 dB +// +//const F32 FAST_MAG_ALPHA = 0.948059448969f; +//const F32 FAST_MAG_BETA = 0.392699081699f; + +inline F32 fastMagnitude(F32 a, F32 b) +{ + a = (a > 0) ? a : -a; + b = (b > 0) ? b : -b; + return(FAST_MAG_ALPHA * llmax(a,b) + FAST_MAG_BETA * llmin(a,b)); +} + + + +//////////////////// +// +// Fast F32/S32 conversions +// +// Culled from www.stereopsis.com/FPU.html + +const F64 LL_DOUBLE_TO_FIX_MAGIC = 68719476736.0*1.5; //2^36 * 1.5, (52-_shiftamt=36) uses limited precisicion to floor +const S32 LL_SHIFT_AMOUNT = 16; //16.16 fixed point representation, + +// Endian dependent code +#ifdef LL_LITTLE_ENDIAN + #define LL_EXP_INDEX 1 + #define LL_MAN_INDEX 0 +#else + #define LL_EXP_INDEX 0 + #define LL_MAN_INDEX 1 +#endif + +/* Deprecated: use llround(), lltrunc(), or llfloor() instead +// ================================================================================================ +// Real2Int +// ================================================================================================ +inline S32 F64toS32(F64 val) +{ + val = val + LL_DOUBLE_TO_FIX_MAGIC; + return ((S32*)&val)[LL_MAN_INDEX] >> LL_SHIFT_AMOUNT; +} + +// ================================================================================================ +// Real2Int +// ================================================================================================ +inline S32 F32toS32(F32 val) +{ + return F64toS32 ((F64)val); +} +*/ + +//////////////////////////////////////////////// +// +// Fast exp and log +// + +// Implementation of fast exp() approximation (from a paper by Nicol N. Schraudolph +// http://www.inf.ethz.ch/~schraudo/pubs/exp.pdf +static union +{ + double d; + struct + { +#ifdef LL_LITTLE_ENDIAN + S32 j, i; +#else + S32 i, j; +#endif + } n; +} LLECO; // not sure what the name means + +#define LL_EXP_A (1048576 * OO_LN2) // use 1512775 for integer +#define LL_EXP_C (60801) // this value of C good for -4 < y < 4 + +#define LL_FAST_EXP(y) (LLECO.n.i = llround(F32(LL_EXP_A*(y))) + (1072693248 - LL_EXP_C), LLECO.d) + + + +inline F32 llfastpow(const F32 x, const F32 y) +{ + return (F32)(LL_FAST_EXP(y * log(x))); +} + + +inline F32 snap_to_sig_figs(F32 foo, S32 sig_figs) +{ + // compute the power of ten + F32 bar = 1.f; + for (S32 i = 0; i < sig_figs; i++) + { + bar *= 10.f; + } + + //F32 new_foo = (F32)llround(foo * bar); + // the llround() implementation sucks. Don't us it. + + F32 sign = (foo > 0.f) ? 1.f : -1.f; + F32 new_foo = F32( S64(foo * bar + sign * 0.5f)); + new_foo /= bar; + + return new_foo; +} + +inline F32 lerp(F32 a, F32 b, F32 u) +{ + return a + ((b - a) * u); +} + +inline F32 lerp2d(F32 x00, F32 x01, F32 x10, F32 x11, F32 u, F32 v) +{ + F32 a = x00 + (x01-x00)*u; + F32 b = x10 + (x11-x10)*u; + F32 r = a + (b-a)*v; + return r; +} + +inline F32 ramp(F32 x, F32 a, F32 b) +{ + return (a == b) ? 0.0f : ((a - x) / (a - b)); +} + +inline F32 rescale(F32 x, F32 x1, F32 x2, F32 y1, F32 y2) +{ + return lerp(y1, y2, ramp(x, x1, x2)); +} + +inline F32 clamp_rescale(F32 x, F32 x1, F32 x2, F32 y1, F32 y2) +{ + if (y1 < y2) + { + return llclamp(rescale(x,x1,x2,y1,y2),y1,y2); + } + else + { + return llclamp(rescale(x,x1,x2,y1,y2),y2,y1); + } +} + + +inline F32 cubic_step( F32 x, F32 x0, F32 x1, F32 s0, F32 s1 ) +{ + if (x <= x0) + return s0; + + if (x >= x1) + return s1; + + F32 f = (x - x0) / (x1 - x0); + + return s0 + (s1 - s0) * (f * f) * (3.0f - 2.0f * f); +} + +inline F32 cubic_step( F32 x ) +{ + x = llclampf(x); + + return (x * x) * (3.0f - 2.0f * x); +} + +inline F32 quadratic_step( F32 x, F32 x0, F32 x1, F32 s0, F32 s1 ) +{ + if (x <= x0) + return s0; + + if (x >= x1) + return s1; + + F32 f = (x - x0) / (x1 - x0); + F32 f_squared = f * f; + + return (s0 * (1.f - f_squared)) + ((s1 - s0) * f_squared); +} + +inline F32 llsimple_angle(F32 angle) +{ + while(angle <= -F_PI) + angle += F_TWO_PI; + while(angle > F_PI) + angle -= F_TWO_PI; + return angle; +} + +//SDK - Renamed this to get_lower_power_two, since this is what this actually does. +inline U32 get_lower_power_two(U32 val, U32 max_power_two) +{ + if(!max_power_two) + { + max_power_two = 1 << 31 ; + } + if(max_power_two & (max_power_two - 1)) + { + return 0 ; + } + + for(; val < max_power_two ; max_power_two >>= 1) ; + + return max_power_two ; +} + +// calculate next highest power of two, limited by max_power_two +// This is taken from a brilliant little code snipped on http://acius2.blogspot.com/2007/11/calculating-next-power-of-2.html +// Basically we convert the binary to a solid string of 1's with the same +// number of digits, then add one. We subtract 1 initially to handle +// the case where the number passed in is actually a power of two. +// WARNING: this only works with 32 bit ints. +inline U32 get_next_power_two(U32 val, U32 max_power_two) +{ + if(!max_power_two) + { + max_power_two = 1 << 31 ; + } + + if(val >= max_power_two) + { + return max_power_two; + } + + val--; + val = (val >> 1) | val; + val = (val >> 2) | val; + val = (val >> 4) | val; + val = (val >> 8) | val; + val = (val >> 16) | val; + val++; + + return val; +} + +//get the gaussian value given the linear distance from axis x and guassian value o +inline F32 llgaussian(F32 x, F32 o) +{ + return 1.f/(F_SQRT_TWO_PI*o)*powf(F_E, -(x*x)/(2*o*o)); +} + +// Include simd math header +#include "llsimdmath.h" + +#endif |