convet c++ to c

[anjaly]

#include "precomp.hpp"


namespace cv
{

static void
FarnebackPolyExp( const Mat& src, Mat& dst, int n, double sigma )
{
int k, x, y;

assert( src.type() == CV_32FC1 );
int width = src.cols;
int height = src.rows;
AutoBuffer<float> kbuf(n*6 + 3), _row((width + n*2)*3);
float* g = kbuf + n;
float* xg = g + n*2 + 1;
float* xxg = xg + n*2 + 1;
float *row = (float*)_row + n*3;

if( sigma < FLT_EPSILON )
sigma = n*0.3;

double s = 0.;
for( x = -n; x <= n; x++ )
{
g[x] = (float)std::exp(-x*x/(2*sigma*sigma));
s += g[x];
}

s = 1./s;
for( x = -n; x <= n; x++ )
{
g[x] = (float)(g[x]*s);
xg[x] = (float)(x*g[x]);
xxg[x] = (float)(x*x*g[x]);
}

Mat_<double> G = Mat_<double>::zeros(6, 6);

for( y = -n; y <= n; y++ )
for( x = -n; x <= n; x++ )
{
G(0,0) += g[y]*g[x];
G(1,1) += g[y]*g[x]*x*x;
G(3,3) += g[y]*g[x]*x*x*x*x;
G(5,5) += g[y]*g[x]*x*x*y*y;
}

//G[0][0] = 1.;
G(2,2) = G(0,3) = G(0,4) = G(3,0) = G(4,0) = G(1,1);
G(4,4) = G(3,3);
G(3,4) = G(4,3) = G(5,5);


Mat_<double> invG = G.inv(DECOMP_CHOLESKY);
double ig11 = invG(1,1), ig03 = invG(0,3), ig33 = invG(3,3), ig55 = invG(5,5);

dst.create( height, width, CV_32FC(5));

for( y = 0; y < height; y++ )
{
float g0 = g[0], g1, g2;
float *srow0 = (float*)(src.data + src.step*y), *srow1 = 0;
float *drow = (float*)(dst.data + dst.step*y);

// vertical part of convolution
for( x = 0; x < width; x++ )
{
row[x*3] = srow0[x]*g0;
row[x*3+1] = row[x*3+2] = 0.f;
}

for( k = 1; k <= n; k++ )
{
g0 = g[k]; g1 = xg[k]; g2 = xxg[k];
srow0 = (float*)(src.data + src.step*std::max(y-k,0));
srow1 = (float*)(src.data + src.step*std::min(y+k,height-1));

for( x = 0; x < width; x++ )
{
float p = srow0[x] + srow1[x];
float t0 = row[x*3] + g0*p;
float t1 = row[x*3+1] + g1*(srow1[x] - srow0[x]);
float t2 = row[x*3+2] + g2*p;

row[x*3] = t0;
row[x*3+1] = t1;
row[x*3+2] = t2;
}
}

// horizontal part of convolution
for( x = 0; x < n*3; x++ )
{
row[-1-x] = row[2-x];
row[width*3+x] = row[width*3+x-3];
}

for( x = 0; x < width; x++ )
{
g0 = g[0];
// r1 ~ 1, r2 ~ x, r3 ~ y, r4 ~ x^2, r5 ~ y^2, r6 ~ xy
double b1 = row[x*3]*g0, b2 = 0, b3 = row[x*3+1]*g0,
b4 = 0, b5 = row[x*3+2]*g0, b6 = 0;

for( k = 1; k <= n; k++ )
{
double tg = row[(x+k)*3] + row[(x-k)*3];
g0 = g[k];
b1 += tg*g0;
b4 += tg*xxg[k];
b2 += (row[(x+k)*3] - row[(x-k)*3])*xg[k];
b3 += (row[(x+k)*3+1] + row[(x-k)*3+1])*g0;
b6 += (row[(x+k)*3+1] - row[(x-k)*3+1])*xg[k];
b5 += (row[(x+k)*3+2] + row[(x-k)*3+2])*g0;
}

// do not store r1
drow[x*5+1] = (float)(b2*ig11);
drow[x*5] = (float)(b3*ig11);
drow[x*5+3] = (float)(b1*ig03 + b4*ig33);
drow[x*5+2] = (float)(b1*ig03 + b5*ig33);
drow[x*5+4] = (float)(b6*ig55);
}
}

row -= n*3;
}

[strongdrink]

so... what exactly is the question?

[eypros]

I think namespace words does not exist in c, all class specific code is invalid and std::max/min also.

You must find equivalent in c or more correctly find what everything does and how you can implemented in a way to c.

[Ben Duncan]

eypros is right. There is no such thing as a conversion when you are using C++ specific keywords.