void BsplineCurveEvaluator::evaluateCurve(const vector<Point> &control_points,
vector<Point> &evaluated_curve_points, const float &animation_length,
const bool &wrap_control_points) const
{
evaluated_curve_points.clear();
vector<Point> cps_;
if (wrap_control_points)
{
cps_.push_back(Point((control_points.end() - 2)->x - animation_length,
(control_points.end() - 2)->y));
cps_.push_back(Point(control_points.back().x - animation_length,
control_points.back().y));
cps_.insert(cps_.end(), control_points.begin(), control_points.end());
cps_.push_back(Point(control_points.front().x + animation_length,
control_points.front().y));
cps_.push_back(Point((control_points.begin() + 1)->x + animation_length,
(control_points.begin() + 1)->y));
}
else
{
cps_.push_back(control_points.front());
cps_.push_back(control_points.front());
cps_.insert(cps_.end(), control_points.begin(), control_points.end());
cps_.push_back(control_points.back());
cps_.push_back(control_points.back());
}
static const Mat4d m = Mat4d(1, 4, 1, 0, 0, 4, 2, 0, 0, 2, 4, 0, 0, 1, 4, 1)
/ 6.0;
BezierCurveEvaluator bce;
for (size_t cp = 0; cp + 3 < cps_.size(); ++cp)
{
const Vec4d bx_vec(cps_[cp].x, cps_[cp + 1].x, cps_[cp + 2].x,
cps_[cp + 3].x);
const Vec4d by_vec(cps_[cp].y, cps_[cp + 1].y, cps_[cp + 2].y,
cps_[cp + 3].y);
Vec4d vx_vec = m * bx_vec;
Vec4d vy_vec = m * by_vec;
vector<Point> vps;
for (int i = 0; i < 4; ++i)
{
vps.push_back(Point(vx_vec[i], vy_vec[i]));
}
vector<Point> evaluated;
bce.evaluateCurve(vps, evaluated, animation_length, false);
// Remove the edge points
evaluated_curve_points.insert(evaluated_curve_points.end(),
evaluated.begin(), evaluated.end() - 2);
}
if (!wrap_control_points)
{
evaluated_curve_points.push_back(Point(0, control_points[0].y));
evaluated_curve_points.push_back(Point(animation_length,
control_points.back().y));
}
}
void BSplineCurveEvaluator::evaluateCurve(
const std::vector<Point>& controlPoints,
std::vector<Point>& evaluatedPoints,
const float& animationLength,
const bool& beWrap) const
{
evaluatedPoints.clear();
if (!beWrap)
{
evaluatedPoints.push_back(Point(0, controlPoints.front().y));
evaluatedPoints.push_back(Point(animationLength, controlPoints.back().y));
}
// a hack to make the endpoints controllable
vector<Point> controlPointsCopy;
if (beWrap)
{
Point start_p1 = Point((controlPoints.end() - 2)->x - animationLength,
(controlPoints.end() - 2)->y);
Point start_p2 = Point((controlPoints.end() - 1)->x - animationLength,
(controlPoints.end() - 1)->y);
Point end_p1 = Point((controlPoints.begin())->x + animationLength,
(controlPoints.begin())->y);
Point end_p2 = Point((controlPoints.begin() + 1)->x + animationLength,
(controlPoints.begin() + 1)->y);
controlPointsCopy.push_back(start_p1);
controlPointsCopy.push_back(start_p2);
controlPointsCopy.insert(controlPointsCopy.end(), controlPoints.begin(), controlPoints.end());
controlPointsCopy.push_back(end_p1);
controlPointsCopy.push_back(end_p2);
}
else
{
controlPointsCopy.push_back(controlPoints.front());
controlPointsCopy.push_back(controlPoints.front());
controlPointsCopy.insert(controlPointsCopy.end(), controlPoints.begin(), controlPoints.end());
controlPointsCopy.push_back(controlPoints.back());
controlPointsCopy.push_back(controlPoints.back());
}
const Mat4d basis = Mat4d(
1, 4, 1, 0,
0, 4, 2, 0,
0, 2, 4, 0,
0, 1, 4, 1) / 6.0;
BezierCurveEvaluator bezierCurveEvaluator;
for (size_t cnt = 0; cnt + 3 < controlPointsCopy.size(); ++cnt)
{
Vec4d param_x(controlPointsCopy[cnt].x, controlPointsCopy[cnt + 1].x,
controlPointsCopy[cnt + 2].x, controlPointsCopy[cnt + 3].x);
Vec4d param_y(controlPointsCopy[cnt].y, controlPointsCopy[cnt + 1].y,
controlPointsCopy[cnt + 2].y, controlPointsCopy[cnt + 3].y);
param_x = basis * param_x;
param_y = basis * param_y;
vector<Point> param_control;
for (int i = 0; i < 4; ++i)
{
param_control.push_back(Point(param_x[i], param_y[i]));
}
vector<Point> param_evaluated;
bezierCurveEvaluator.evaluateCurve(param_control, param_evaluated, animationLength, false);
evaluatedPoints.insert(evaluatedPoints.end(), param_evaluated.begin(), param_evaluated.end()-2);
}
}