void writeBezier(ofstream &out, unsigned step, double px[], double py[]) {
out << "%%%%%%%%%%%%%%%%%%" << endl;
out << "%% Bezier-Kurve %%" << endl;
out << "%%%%%%%%%%%%%%%%%%" << endl;
out << "\\drawline";
for (unsigned i= 0; i <= step; ++i) {
double x;
double y;
curvePoint(double(i)/double(step), px, x);
curvePoint(double(i)/double(step), py, y);
out << "(" << OFS+(int)x << "," << OFS+(int)y << ")";
if ((i % 5) == 4) {
out << endl << "\t";
}
}
out << endl;
}
Coord computeOpenUniformBsplinePoint(const vector<Coord> &controlPoints, const float t, const unsigned int curveDegree) {
assert(controlPoints.size() > 3);
unsigned int nbKnots = controlPoints.size() + curveDegree + 1;
float stepKnots = 1.0f / ((static_cast<float>(nbKnots) - 2.0f * (static_cast<float>(curveDegree) + 1.0f)) + 2.0f - 1.0f);
if (t == 0.0) {
return controlPoints[0];
}
else if (t >= 1.0) {
return controlPoints[controlPoints.size() - 1];
}
else {
float* coeffs = new float[curveDegree + 1];
memset(coeffs, 0, (curveDegree + 1) * sizeof(float));
int k = curveDegree;
int cpt = 0;
while (t > (cpt*stepKnots) && t >= ((cpt+1)*stepKnots)) {
++k;
++cpt;
}
float knotVal = (cpt * stepKnots);
coeffs[curveDegree] = 1.0;
for (int i = 1 ; i <= static_cast<int>(curveDegree) ; ++i) {
coeffs[curveDegree-i] = (clamp(knotVal + stepKnots, 0.0, 1.0) - t) / (clamp(knotVal + stepKnots, 0.0, 1.0) - clamp(knotVal + (-i+1) * stepKnots, 0.0, 1.0)) * coeffs[curveDegree-i+1];
int tabIdx = curveDegree-i+1;
for (int j = -i+1 ; j <= -1 ; ++j) {
coeffs[tabIdx] = ((t - clamp(knotVal + j * stepKnots, 0.0, 1.0)) / (clamp(knotVal + (j+i) * stepKnots, 0.0, 1.0) - clamp(knotVal + j * stepKnots, 0.0, 1.0))) * coeffs[tabIdx] + ((clamp(knotVal + (j+i+1) * stepKnots, 0.0, 1.0) - t) / (clamp(knotVal + (j+i+1) * stepKnots, 0.0, 1.0) - clamp(knotVal + (j+1) * stepKnots, 0.0, 1.0))) * coeffs[tabIdx+1];
++tabIdx;
}
coeffs[curveDegree] = ((t - knotVal) / (clamp(knotVal + i * stepKnots, 0.0, 1.0) - knotVal)) * coeffs[curveDegree];
}
Coord curvePoint(0.0f, 0.0f, 0.0f);
int startIdx = k - curveDegree;
for (unsigned int i = 0 ; i <= curveDegree ; ++i) {
curvePoint += coeffs[i] * controlPoints[startIdx + i];
}
delete [] coeffs;
return curvePoint;
}
}
void curvePoints(S_Curve *pCurve, int n, S_CoordVec *pPoints)
{
double step, t = 0.0;
int i, size;
IZG_ASSERT(pCurve && pPoints);
/* uprava velikosti vysledneho seznamu bodu */
size = curveSize(pCurve);
cvecResize(pPoints, size);
/* pocet ridicich bodu */
if( size < 2 || n < 2 ) return;
/* vypocet velikosti kroku */
step = 1.0 / (n - 1);
/* generovani bodu */
for( i = 0; i < n; ++i, t += step )
{
/* vypocet bodu krivky */
cvecGet(pPoints, i) = curvePoint(pCurve, t);
}
}