Mirrors/bx
1
0
Fork 0
mirror of https://github.com/bkaradzic/bx.git synced 2026-02-20 13:53:15 +01:00
Code Issues Packages Projects Releases Wiki Activity

Added calcLinearFit.

Browse Source
This commit is contained in:
Branimir Karadžić
2015-07-02 12:03:48 -07:00
parent d6b8d3c04e
commit fe88ee4190
1 changed files with 76 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

76
include/bx/fpumath.h
View File

@@ -833,6 +833,82 @@ namespace bx
_result[3] = -vec3Dot(normal, _va);
}
inline 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;
}
inline 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];
bx::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;
}
inline void rgbToHsv(float _hsv[3], const float _rgb[3])
{
const float rr = _rgb[0];