NouVeL/ADVect/ext/bgfx/bx/src/math.cpp
2022-08-18 12:17:43 -04:00

782 lines
24 KiB
C++

/*
* Copyright 2011-2022 Branimir Karadzic. All rights reserved.
* License: https://github.com/bkaradzic/bx/blob/master/LICENSE
*/
#include <bx/math.h>
#include <bx/uint32_t.h>
namespace bx
{
const float kInfinity = bitsToFloat(UINT32_C(0x7f800000) );
namespace
{
constexpr float kSinC2 = -0.16666667163372039794921875f;
constexpr float kSinC4 = 8.333347737789154052734375e-3f;
constexpr float kSinC6 = -1.9842604524455964565277099609375e-4f;
constexpr float kSinC8 = 2.760012648650445044040679931640625e-6f;
constexpr float kSinC10 = -2.50293279435709337121807038784027099609375e-8f;
constexpr float kCosC2 = -0.5f;
constexpr float kCosC4 = 4.166664183139801025390625e-2f;
constexpr float kCosC6 = -1.388833043165504932403564453125e-3f;
constexpr float kCosC8 = 2.47562347794882953166961669921875e-5f;
constexpr float kCosC10 = -2.59630184018533327616751194000244140625e-7f;
} // namespace
BX_CONST_FUNC float cos(float _a)
{
const float scaled = _a * 2.0f*kInvPi;
const float real = floor(scaled);
const float xx = _a - real * kPiHalf;
const int32_t bits = int32_t(real) & 3;
float c0, c2, c4, c6, c8, c10;
if (bits == 0
|| bits == 2)
{
c0 = 1.0f;
c2 = kCosC2;
c4 = kCosC4;
c6 = kCosC6;
c8 = kCosC8;
c10 = kCosC10;
}
else
{
c0 = xx;
c2 = kSinC2;
c4 = kSinC4;
c6 = kSinC6;
c8 = kSinC8;
c10 = kSinC10;
}
const float xsq = square(xx);
const float tmp0 = mad(c10, xsq, c8 );
const float tmp1 = mad(tmp0, xsq, c6 );
const float tmp2 = mad(tmp1, xsq, c4 );
const float tmp3 = mad(tmp2, xsq, c2 );
const float tmp4 = mad(tmp3, xsq, 1.0);
const float result = tmp4 * c0;
return bits == 1 || bits == 2
? -result
: result
;
}
namespace
{
constexpr float kAcosC0 = 1.5707288f;
constexpr float kAcosC1 = -0.2121144f;
constexpr float kAcosC2 = 0.0742610f;
constexpr float kAcosC3 = -0.0187293f;
} // namespace
BX_CONST_FUNC float acos(float _a)
{
const float absa = abs(_a);
const float tmp0 = mad(kAcosC3, absa, kAcosC2);
const float tmp1 = mad(tmp0, absa, kAcosC1);
const float tmp2 = mad(tmp1, absa, kAcosC0);
const float tmp3 = tmp2 * sqrt(1.0f - absa);
const float negate = float(_a < 0.0f);
const float tmp4 = tmp3 - 2.0f*negate*tmp3;
const float result = negate*kPi + tmp4;
return result;
}
namespace
{
constexpr float kAtan2C0 = -0.013480470f;
constexpr float kAtan2C1 = 0.057477314f;
constexpr float kAtan2C2 = -0.121239071f;
constexpr float kAtan2C3 = 0.195635925f;
constexpr float kAtan2C4 = -0.332994597f;
constexpr float kAtan2C5 = 0.999995630f;
} // namespace
BX_CONST_FUNC float atan2(float _y, float _x)
{
const float ax = abs(_x);
const float ay = abs(_y);
const float maxaxy = max(ax, ay);
const float minaxy = min(ax, ay);
if (maxaxy == 0.0f)
{
return 0.0f*sign(_y);
}
const float mxy = minaxy / maxaxy;
const float mxysq = square(mxy);
const float tmp0 = mad(kAtan2C0, mxysq, kAtan2C1);
const float tmp1 = mad(tmp0, mxysq, kAtan2C2);
const float tmp2 = mad(tmp1, mxysq, kAtan2C3);
const float tmp3 = mad(tmp2, mxysq, kAtan2C4);
const float tmp4 = mad(tmp3, mxysq, kAtan2C5);
const float tmp5 = tmp4 * mxy;
const float tmp6 = ay > ax ? kPiHalf - tmp5 : tmp5;
const float tmp7 = _x < 0.0f ? kPi - tmp6 : tmp6;
const float result = sign(_y)*tmp7;
return result;
}
BX_CONST_FUNC float ldexp(float _a, int32_t _b)
{
const uint32_t ftob = floatToBits(_a);
const uint32_t masked = uint32_and(ftob, UINT32_C(0xff800000) );
const uint32_t expsign0 = uint32_sra(masked, 23);
const uint32_t tmp = uint32_iadd(expsign0, _b);
const uint32_t expsign1 = uint32_sll(tmp, 23);
const uint32_t mantissa = uint32_and(ftob, UINT32_C(0x007fffff) );
const uint32_t bits = uint32_or(mantissa, expsign1);
const float result = bitsToFloat(bits);
return result;
}
float frexp(float _a, int32_t* _outExp)
{
const uint32_t ftob = floatToBits(_a);
const uint32_t masked0 = uint32_and(ftob, UINT32_C(0x7f800000) );
const uint32_t exp0 = uint32_srl(masked0, 23);
const uint32_t masked1 = uint32_and(ftob, UINT32_C(0x807fffff) );
const uint32_t bits = uint32_or(masked1, UINT32_C(0x3f000000) );
const float result = bitsToFloat(bits);
*_outExp = int32_t(exp0 - 0x7e);
return result;
}
namespace
{
constexpr float kExpC0 = 1.66666666666666019037e-01f;
constexpr float kExpC1 = -2.77777777770155933842e-03f;
constexpr float kExpC2 = 6.61375632143793436117e-05f;
constexpr float kExpC3 = -1.65339022054652515390e-06f;
constexpr float kExpC4 = 4.13813679705723846039e-08f;
} // namespace
BX_CONST_FUNC float exp(float _a)
{
if (abs(_a) <= kNearZero)
{
return _a + 1.0f;
}
const float kk = round(_a*kInvLogNat2);
const float hi = _a - kk*kLogNat2Hi;
const float lo = kk*kLogNat2Lo;
const float hml = hi - lo;
const float hmlsq = square(hml);
const float tmp0 = mad(kExpC4, hmlsq, kExpC3);
const float tmp1 = mad(tmp0, hmlsq, kExpC2);
const float tmp2 = mad(tmp1, hmlsq, kExpC1);
const float tmp3 = mad(tmp2, hmlsq, kExpC0);
const float tmp4 = hml - hmlsq * tmp3;
const float tmp5 = hml*tmp4/(2.0f-tmp4);
const float tmp6 = 1.0f - ( (lo - tmp5) - hi);
const float result = ldexp(tmp6, int32_t(kk) );
return result;
}
namespace
{
constexpr float kLogC0 = 6.666666666666735130e-01f;
constexpr float kLogC1 = 3.999999999940941908e-01f;
constexpr float kLogC2 = 2.857142874366239149e-01f;
constexpr float kLogC3 = 2.222219843214978396e-01f;
constexpr float kLogC4 = 1.818357216161805012e-01f;
constexpr float kLogC5 = 1.531383769920937332e-01f;
constexpr float kLogC6 = 1.479819860511658591e-01f;
} // namespace
BX_CONST_FUNC float log(float _a)
{
int32_t exp;
float ff = frexp(_a, &exp);
if (ff < kSqrt2*0.5f)
{
ff *= 2.0f;
--exp;
}
ff -= 1.0f;
const float kk = float(exp);
const float hi = kk*kLogNat2Hi;
const float lo = kk*kLogNat2Lo;
const float ss = ff / (2.0f + ff);
const float s2 = square(ss);
const float s4 = square(s2);
const float tmp0 = mad(kLogC6, s4, kLogC4);
const float tmp1 = mad(tmp0, s4, kLogC2);
const float tmp2 = mad(tmp1, s4, kLogC0);
const float t1 = s2*tmp2;
const float tmp3 = mad(kLogC5, s4, kLogC3);
const float tmp4 = mad(tmp3, s4, kLogC1);
const float t2 = s4*tmp4;
const float t12 = t1 + t2;
const float hfsq = 0.5f*square(ff);
const float result = hi - ( (hfsq - (ss*(hfsq+t12) + lo) ) - ff);
return result;
}
void mtxLookAt(float* _result, const Vec3& _eye, const Vec3& _at, const Vec3& _up, Handness::Enum _handness)
{
const Vec3 view = normalize(
Handness::Right == _handness
? sub(_eye, _at)
: sub(_at, _eye)
);
const Vec3 uxv = cross(_up, view);
const Vec3 right = normalize(uxv);
const Vec3 up = cross(view, right);
memSet(_result, 0, sizeof(float)*16);
_result[ 0] = right.x;
_result[ 1] = up.x;
_result[ 2] = view.x;
_result[ 4] = right.y;
_result[ 5] = up.y;
_result[ 6] = view.y;
_result[ 8] = right.z;
_result[ 9] = up.z;
_result[10] = view.z;
_result[12] = -dot(right, _eye);
_result[13] = -dot(up, _eye);
_result[14] = -dot(view, _eye);
_result[15] = 1.0f;
}
static void mtxProjXYWH(float* _result, float _x, float _y, float _width, float _height, float _near, float _far, bool _homogeneousNdc, Handness::Enum _handness)
{
const float diff = _far-_near;
const float aa = _homogeneousNdc ? ( _far+_near)/diff : _far/diff;
const float bb = _homogeneousNdc ? (2.0f*_far*_near)/diff : _near*aa;
memSet(_result, 0, sizeof(float)*16);
_result[ 0] = _width;
_result[ 5] = _height;
_result[ 8] = (Handness::Right == _handness) ? _x : -_x;
_result[ 9] = (Handness::Right == _handness) ? _y : -_y;
_result[10] = (Handness::Right == _handness) ? -aa : aa;
_result[11] = (Handness::Right == _handness) ? -1.0f : 1.0f;
_result[14] = -bb;
}
void mtxProj(float* _result, float _ut, float _dt, float _lt, float _rt, float _near, float _far, bool _homogeneousNdc, Handness::Enum _handness)
{
const float invDiffRl = 1.0f/(_rt - _lt);
const float invDiffUd = 1.0f/(_ut - _dt);
const float width = 2.0f*_near * invDiffRl;
const float height = 2.0f*_near * invDiffUd;
const float xx = (_rt + _lt) * invDiffRl;
const float yy = (_ut + _dt) * invDiffUd;
mtxProjXYWH(_result, xx, yy, width, height, _near, _far, _homogeneousNdc, _handness);
}
void mtxProj(float* _result, const float _fov[4], float _near, float _far, bool _homogeneousNdc, Handness::Enum _handness)
{
mtxProj(_result, _fov[0], _fov[1], _fov[2], _fov[3], _near, _far, _homogeneousNdc, _handness);
}
void mtxProj(float* _result, float _fovy, float _aspect, float _near, float _far, bool _homogeneousNdc, Handness::Enum _handness)
{
const float height = 1.0f/tan(toRad(_fovy)*0.5f);
const float width = height * 1.0f/_aspect;
mtxProjXYWH(_result, 0.0f, 0.0f, width, height, _near, _far, _homogeneousNdc, _handness);
}
static void mtxProjInfXYWH(float* _result, float _x, float _y, float _width, float _height, float _near, bool _homogeneousNdc, Handness::Enum _handness, NearFar::Enum _nearFar)
{
float aa;
float bb;
if (NearFar::Reverse == _nearFar)
{
aa = _homogeneousNdc ? -1.0f : 0.0f;
bb = _homogeneousNdc ? -2.0f*_near : -_near;
}
else
{
aa = 1.0f;
bb = _homogeneousNdc ? 2.0f*_near : _near;
}
memSet(_result, 0, sizeof(float)*16);
_result[ 0] = _width;
_result[ 5] = _height;
_result[ 8] = (Handness::Right == _handness) ? _x : -_x;
_result[ 9] = (Handness::Right == _handness) ? _y : -_y;
_result[10] = (Handness::Right == _handness) ? -aa : aa;
_result[11] = (Handness::Right == _handness) ? -1.0f : 1.0f;
_result[14] = -bb;
}
void mtxProjInf(float* _result, float _ut, float _dt, float _lt, float _rt, float _near, bool _homogeneousNdc, Handness::Enum _handness, NearFar::Enum _nearFar)
{
const float invDiffRl = 1.0f/(_rt - _lt);
const float invDiffUd = 1.0f/(_ut - _dt);
const float width = 2.0f*_near * invDiffRl;
const float height = 2.0f*_near * invDiffUd;
const float xx = (_rt + _lt) * invDiffRl;
const float yy = (_ut + _dt) * invDiffUd;
mtxProjInfXYWH(_result, xx, yy, width, height, _near, _homogeneousNdc, _handness, _nearFar);
}
void mtxProjInf(float* _result, const float _fov[4], float _near, bool _homogeneousNdc, Handness::Enum _handness, NearFar::Enum _nearFar)
{
mtxProjInf(_result, _fov[0], _fov[1], _fov[2], _fov[3], _near, _homogeneousNdc, _handness, _nearFar);
}
void mtxProjInf(float* _result, float _fovy, float _aspect, float _near, bool _homogeneousNdc, Handness::Enum _handness, NearFar::Enum _nearFar)
{
const float height = 1.0f/tan(toRad(_fovy)*0.5f);
const float width = height * 1.0f/_aspect;
mtxProjInfXYWH(_result, 0.0f, 0.0f, width, height, _near, _homogeneousNdc, _handness, _nearFar);
}
void mtxOrtho(float* _result, float _left, float _right, float _bottom, float _top, float _near, float _far, float _offset, bool _homogeneousNdc, Handness::Enum _handness)
{
const float aa = 2.0f/(_right - _left);
const float bb = 2.0f/(_top - _bottom);
const float cc = (_homogeneousNdc ? 2.0f : 1.0f) / (_far - _near);
const float dd = (_left + _right )/(_left - _right);
const float ee = (_top + _bottom)/(_bottom - _top );
const float ff = _homogeneousNdc
? (_near + _far)/(_near - _far)
: _near /(_near - _far)
;
memSet(_result, 0, sizeof(float)*16);
_result[ 0] = aa;
_result[ 5] = bb;
_result[10] = Handness::Right == _handness ? -cc : cc;
_result[12] = dd + _offset;
_result[13] = ee;
_result[14] = ff;
_result[15] = 1.0f;
}
void mtxRotateX(float* _result, float _ax)
{
const float sx = sin(_ax);
const float cx = cos(_ax);
memSet(_result, 0, sizeof(float)*16);
_result[ 0] = 1.0f;
_result[ 5] = cx;
_result[ 6] = -sx;
_result[ 9] = sx;
_result[10] = cx;
_result[15] = 1.0f;
}
void mtxRotateY(float* _result, float _ay)
{
const float sy = sin(_ay);
const float cy = cos(_ay);
memSet(_result, 0, sizeof(float)*16);
_result[ 0] = cy;
_result[ 2] = sy;
_result[ 5] = 1.0f;
_result[ 8] = -sy;
_result[10] = cy;
_result[15] = 1.0f;
}
void mtxRotateZ(float* _result, float _az)
{
const float sz = sin(_az);
const float cz = cos(_az);
memSet(_result, 0, sizeof(float)*16);
_result[ 0] = cz;
_result[ 1] = -sz;
_result[ 4] = sz;
_result[ 5] = cz;
_result[10] = 1.0f;
_result[15] = 1.0f;
}
void mtxRotateXY(float* _result, float _ax, float _ay)
{
const float sx = sin(_ax);
const float cx = cos(_ax);
const float sy = sin(_ay);
const float cy = cos(_ay);
memSet(_result, 0, sizeof(float)*16);
_result[ 0] = cy;
_result[ 2] = sy;
_result[ 4] = sx*sy;
_result[ 5] = cx;
_result[ 6] = -sx*cy;
_result[ 8] = -cx*sy;
_result[ 9] = sx;
_result[10] = cx*cy;
_result[15] = 1.0f;
}
void mtxRotateXYZ(float* _result, float _ax, float _ay, float _az)
{
const float sx = sin(_ax);
const float cx = cos(_ax);
const float sy = sin(_ay);
const float cy = cos(_ay);
const float sz = sin(_az);
const float cz = cos(_az);
memSet(_result, 0, sizeof(float)*16);
_result[ 0] = cy*cz;
_result[ 1] = -cy*sz;
_result[ 2] = sy;
_result[ 4] = cz*sx*sy + cx*sz;
_result[ 5] = cx*cz - sx*sy*sz;
_result[ 6] = -cy*sx;
_result[ 8] = -cx*cz*sy + sx*sz;
_result[ 9] = cz*sx + cx*sy*sz;
_result[10] = cx*cy;
_result[15] = 1.0f;
}
void mtxRotateZYX(float* _result, float _ax, float _ay, float _az)
{
const float sx = sin(_ax);
const float cx = cos(_ax);
const float sy = sin(_ay);
const float cy = cos(_ay);
const float sz = sin(_az);
const float cz = cos(_az);
memSet(_result, 0, sizeof(float)*16);
_result[ 0] = cy*cz;
_result[ 1] = cz*sx*sy-cx*sz;
_result[ 2] = cx*cz*sy+sx*sz;
_result[ 4] = cy*sz;
_result[ 5] = cx*cz + sx*sy*sz;
_result[ 6] = -cz*sx + cx*sy*sz;
_result[ 8] = -sy;
_result[ 9] = cy*sx;
_result[10] = cx*cy;
_result[15] = 1.0f;
};
void mtxSRT(float* _result, float _sx, float _sy, float _sz, float _ax, float _ay, float _az, float _tx, float _ty, float _tz)
{
const float sx = sin(_ax);
const float cx = cos(_ax);
const float sy = sin(_ay);
const float cy = cos(_ay);
const float sz = sin(_az);
const float cz = cos(_az);
const float sxsz = sx*sz;
const float cycz = cy*cz;
_result[ 0] = _sx * (cycz - sxsz*sy);
_result[ 1] = _sx * -cx*sz;
_result[ 2] = _sx * (cz*sy + cy*sxsz);
_result[ 3] = 0.0f;
_result[ 4] = _sy * (cz*sx*sy + cy*sz);
_result[ 5] = _sy * cx*cz;
_result[ 6] = _sy * (sy*sz -cycz*sx);
_result[ 7] = 0.0f;
_result[ 8] = _sz * -cx*sy;
_result[ 9] = _sz * sx;
_result[10] = _sz * cx*cy;
_result[11] = 0.0f;
_result[12] = _tx;
_result[13] = _ty;
_result[14] = _tz;
_result[15] = 1.0f;
}
void mtx3Inverse(float* _result, const float* _a)
{
const float xx = _a[0];
const float xy = _a[1];
const float xz = _a[2];
const float yx = _a[3];
const float yy = _a[4];
const float yz = _a[5];
const float zx = _a[6];
const float zy = _a[7];
const float zz = _a[8];
float det = 0.0f;
det += xx * (yy*zz - yz*zy);
det -= xy * (yx*zz - yz*zx);
det += xz * (yx*zy - yy*zx);
float invDet = 1.0f/det;
_result[0] = +(yy*zz - yz*zy) * invDet;
_result[1] = -(xy*zz - xz*zy) * invDet;
_result[2] = +(xy*yz - xz*yy) * invDet;
_result[3] = -(yx*zz - yz*zx) * invDet;
_result[4] = +(xx*zz - xz*zx) * invDet;
_result[5] = -(xx*yz - xz*yx) * invDet;
_result[6] = +(yx*zy - yy*zx) * invDet;
_result[7] = -(xx*zy - xy*zx) * invDet;
_result[8] = +(xx*yy - xy*yx) * invDet;
}
void mtxInverse(float* _result, const float* _a)
{
const float xx = _a[ 0];
const float xy = _a[ 1];
const float xz = _a[ 2];
const float xw = _a[ 3];
const float yx = _a[ 4];
const float yy = _a[ 5];
const float yz = _a[ 6];
const float yw = _a[ 7];
const float zx = _a[ 8];
const float zy = _a[ 9];
const float zz = _a[10];
const float zw = _a[11];
const float wx = _a[12];
const float wy = _a[13];
const float wz = _a[14];
const float ww = _a[15];
float det = 0.0f;
det += xx * (yy*(zz*ww - zw*wz) - yz*(zy*ww - zw*wy) + yw*(zy*wz - zz*wy) );
det -= xy * (yx*(zz*ww - zw*wz) - yz*(zx*ww - zw*wx) + yw*(zx*wz - zz*wx) );
det += xz * (yx*(zy*ww - zw*wy) - yy*(zx*ww - zw*wx) + yw*(zx*wy - zy*wx) );
det -= xw * (yx*(zy*wz - zz*wy) - yy*(zx*wz - zz*wx) + yz*(zx*wy - zy*wx) );
float invDet = 1.0f/det;
_result[ 0] = +(yy*(zz*ww - wz*zw) - yz*(zy*ww - wy*zw) + yw*(zy*wz - wy*zz) ) * invDet;
_result[ 1] = -(xy*(zz*ww - wz*zw) - xz*(zy*ww - wy*zw) + xw*(zy*wz - wy*zz) ) * invDet;
_result[ 2] = +(xy*(yz*ww - wz*yw) - xz*(yy*ww - wy*yw) + xw*(yy*wz - wy*yz) ) * invDet;
_result[ 3] = -(xy*(yz*zw - zz*yw) - xz*(yy*zw - zy*yw) + xw*(yy*zz - zy*yz) ) * invDet;
_result[ 4] = -(yx*(zz*ww - wz*zw) - yz*(zx*ww - wx*zw) + yw*(zx*wz - wx*zz) ) * invDet;
_result[ 5] = +(xx*(zz*ww - wz*zw) - xz*(zx*ww - wx*zw) + xw*(zx*wz - wx*zz) ) * invDet;
_result[ 6] = -(xx*(yz*ww - wz*yw) - xz*(yx*ww - wx*yw) + xw*(yx*wz - wx*yz) ) * invDet;
_result[ 7] = +(xx*(yz*zw - zz*yw) - xz*(yx*zw - zx*yw) + xw*(yx*zz - zx*yz) ) * invDet;
_result[ 8] = +(yx*(zy*ww - wy*zw) - yy*(zx*ww - wx*zw) + yw*(zx*wy - wx*zy) ) * invDet;
_result[ 9] = -(xx*(zy*ww - wy*zw) - xy*(zx*ww - wx*zw) + xw*(zx*wy - wx*zy) ) * invDet;
_result[10] = +(xx*(yy*ww - wy*yw) - xy*(yx*ww - wx*yw) + xw*(yx*wy - wx*yy) ) * invDet;
_result[11] = -(xx*(yy*zw - zy*yw) - xy*(yx*zw - zx*yw) + xw*(yx*zy - zx*yy) ) * invDet;
_result[12] = -(yx*(zy*wz - wy*zz) - yy*(zx*wz - wx*zz) + yz*(zx*wy - wx*zy) ) * invDet;
_result[13] = +(xx*(zy*wz - wy*zz) - xy*(zx*wz - wx*zz) + xz*(zx*wy - wx*zy) ) * invDet;
_result[14] = -(xx*(yy*wz - wy*yz) - xy*(yx*wz - wx*yz) + xz*(yx*wy - wx*yy) ) * invDet;
_result[15] = +(xx*(yy*zz - zy*yz) - xy*(yx*zz - zx*yz) + xz*(yx*zy - zx*yy) ) * invDet;
}
void mtx3Cofactor(float* _result, const float* _a)
{
const float xx = _a[0];
const float xy = _a[1];
const float xz = _a[2];
const float yx = _a[3];
const float yy = _a[4];
const float yz = _a[5];
const float zx = _a[6];
const float zy = _a[7];
const float zz = _a[8];
_result[0] = +(yy*zz - yz * zy);
_result[1] = -(yx*zz - yz * zx);
_result[2] = +(yx*zy - yy * zx);
_result[3] = -(xy*zz - xz * zy);
_result[4] = +(xx*zz - xz * zx);
_result[5] = -(xx*zy - xy * zx);
_result[6] = +(xy*yz - xz * yy);
_result[7] = -(xx*yz - xz * yx);
_result[8] = +(xx*yy - xy * yx);
}
void mtxCofactor(float* _result, const float* _a)
{
const float xx = _a[0];
const float xy = _a[1];
const float xz = _a[2];
const float xw = _a[3];
const float yx = _a[4];
const float yy = _a[5];
const float yz = _a[6];
const float yw = _a[7];
const float zx = _a[8];
const float zy = _a[9];
const float zz = _a[10];
const float zw = _a[11];
const float wx = _a[12];
const float wy = _a[13];
const float wz = _a[14];
const float ww = _a[15];
_result[ 0] = +(yy*(zz*ww - wz * zw) - yz * (zy*ww - wy * zw) + yw * (zy*wz - wy * zz) );
_result[ 1] = -(yx*(zz*ww - wz * zw) - yz * (zx*ww - wx * zw) + yw * (zx*wz - wx * zz) );
_result[ 2] = +(yx*(zy*ww - wy * zw) - yy * (zx*ww - wx * zw) + yw * (zx*wy - wx * zy) );
_result[ 3] = -(yx*(zy*wz - wy * zz) - yy * (zx*wz - wx * zz) + yz * (zx*wy - wx * zy) );
_result[ 4] = -(xy*(zz*ww - wz * zw) - xz * (zy*ww - wy * zw) + xw * (zy*wz - wy * zz) );
_result[ 5] = +(xx*(zz*ww - wz * zw) - xz * (zx*ww - wx * zw) + xw * (zx*wz - wx * zz) );
_result[ 6] = -(xx*(zy*ww - wy * zw) - xy * (zx*ww - wx * zw) + xw * (zx*wy - wx * zy) );
_result[ 7] = +(xx*(zy*wz - wy * zz) - xy * (zx*wz - wx * zz) + xz * (zx*wy - wx * zy) );
_result[ 8] = +(xy*(yz*ww - wz * yw) - xz * (yy*ww - wy * yw) + xw * (yy*wz - wy * yz) );
_result[ 9] = -(xx*(yz*ww - wz * yw) - xz * (yx*ww - wx * yw) + xw * (yx*wz - wx * yz) );
_result[10] = +(xx*(yy*ww - wy * yw) - xy * (yx*ww - wx * yw) + xw * (yx*wy - wx * yy) );
_result[11] = -(xx*(yy*wz - wy * yz) - xy * (yx*wz - wx * yz) + xz * (yx*wy - wx * yy) );
_result[12] = -(xy*(yz*zw - zz * yw) - xz * (yy*zw - zy * yw) + xw * (yy*zz - zy * yz) );
_result[13] = +(xx*(yz*zw - zz * yw) - xz * (yx*zw - zx * yw) + xw * (yx*zz - zx * yz) );
_result[14] = -(xx*(yy*zw - zy * yw) - xy * (yx*zw - zx * yw) + xw * (yx*zy - zx * yy) );
_result[15] = +(xx*(yy*zz - zy * yz) - xy * (yx*zz - zx * yz) + xz * (yx*zy - zx * yy) );
}
void calcLinearFit2D(float _result[2], const void* _points, uint32_t _stride, uint32_t _numPoints)
{
float sumX = 0.0f;
float sumY = 0.0f;
float sumXX = 0.0f;
float sumXY = 0.0f;
const uint8_t* ptr = (const uint8_t*)_points;
for (uint32_t ii = 0; ii < _numPoints; ++ii, ptr += _stride)
{
const float* point = (const float*)ptr;
float xx = point[0];
float yy = point[1];
sumX += xx;
sumY += yy;
sumXX += xx*xx;
sumXY += xx*yy;
}
// [ sum(x^2) sum(x) ] [ A ] = [ sum(x*y) ]
// [ sum(x) numPoints ] [ B ] [ sum(y) ]
float det = (sumXX*_numPoints - sumX*sumX);
float invDet = 1.0f/det;
_result[0] = (-sumX * sumY + _numPoints * sumXY) * invDet;
_result[1] = (sumXX * sumY - sumX * sumXY) * invDet;
}
void calcLinearFit3D(float _result[3], const void* _points, uint32_t _stride, uint32_t _numPoints)
{
float sumX = 0.0f;
float sumY = 0.0f;
float sumZ = 0.0f;
float sumXX = 0.0f;
float sumXY = 0.0f;
float sumXZ = 0.0f;
float sumYY = 0.0f;
float sumYZ = 0.0f;
const uint8_t* ptr = (const uint8_t*)_points;
for (uint32_t ii = 0; ii < _numPoints; ++ii, ptr += _stride)
{
const float* point = (const float*)ptr;
float xx = point[0];
float yy = point[1];
float zz = point[2];
sumX += xx;
sumY += yy;
sumZ += zz;
sumXX += xx*xx;
sumXY += xx*yy;
sumXZ += xx*zz;
sumYY += yy*yy;
sumYZ += yy*zz;
}
// [ sum(x^2) sum(x*y) sum(x) ] [ A ] [ sum(x*z) ]
// [ sum(x*y) sum(y^2) sum(y) ] [ B ] = [ sum(y*z) ]
// [ sum(x) sum(y) numPoints ] [ C ] [ sum(z) ]
float mtx[9] =
{
sumXX, sumXY, sumX,
sumXY, sumYY, sumY,
sumX, sumY, float(_numPoints),
};
float invMtx[9];
mtx3Inverse(invMtx, mtx);
_result[0] = invMtx[0]*sumXZ + invMtx[1]*sumYZ + invMtx[2]*sumZ;
_result[1] = invMtx[3]*sumXZ + invMtx[4]*sumYZ + invMtx[5]*sumZ;
_result[2] = invMtx[6]*sumXZ + invMtx[7]*sumYZ + invMtx[8]*sumZ;
}
void rgbToHsv(float _hsv[3], const float _rgb[3])
{
const float rr = _rgb[0];
const float gg = _rgb[1];
const float bb = _rgb[2];
const float s0 = step(bb, gg);
const float px = lerp(bb, gg, s0);
const float py = lerp(gg, bb, s0);
const float pz = lerp(-1.0f, 0.0f, s0);
const float pw = lerp(2.0f/3.0f, -1.0f/3.0f, s0);
const float s1 = step(px, rr);
const float qx = lerp(px, rr, s1);
const float qy = py;
const float qz = lerp(pw, pz, s1);
const float qw = lerp(rr, px, s1);
const float dd = qx - min(qw, qy);
const float ee = 1.0e-10f;
_hsv[0] = abs(qz + (qw - qy) / (6.0f * dd + ee) );
_hsv[1] = dd / (qx + ee);
_hsv[2] = qx;
}
void hsvToRgb(float _rgb[3], const float _hsv[3])
{
const float hh = _hsv[0];
const float ss = _hsv[1];
const float vv = _hsv[2];
const float px = abs(fract(hh + 1.0f ) * 6.0f - 3.0f);
const float py = abs(fract(hh + 2.0f/3.0f) * 6.0f - 3.0f);
const float pz = abs(fract(hh + 1.0f/3.0f) * 6.0f - 3.0f);
_rgb[0] = vv * lerp(1.0f, clamp(px - 1.0f, 0.0f, 1.0f), ss);
_rgb[1] = vv * lerp(1.0f, clamp(py - 1.0f, 0.0f, 1.0f), ss);
_rgb[2] = vv * lerp(1.0f, clamp(pz - 1.0f, 0.0f, 1.0f), ss);
}
} // namespace bx