// This is a binary search algorithm that we
// need to use to find the Y value that
// corresponds with our given X value.
// inputXValue is the target value here.
// This function only works if the Bezier curve
// does not have multiple Y values for any
// given X value, so make sure that the
// control points of the Bezier curve stay
// inside the bounds of the end points.
double BezierCurve::getOutput (double inputXValue)
{
double totalNumberOfSamples = mPointD.xValue;
double xTolerance = 1.0 / totalNumberOfSamples;
double lowerBound = 0.0;
double upperBound = 1.0;
double currentPositionInTime = 0.5;
double currentXValue = getPointOnCurve (currentPositionInTime).xValue;
while (std::abs (inputXValue - currentXValue) > xTolerance)
{
if (inputXValue > currentXValue)
lowerBound = currentPositionInTime;
else
upperBound = currentPositionInTime;
currentPositionInTime = (lowerBound + upperBound) * 0.5;
currentXValue = getPointOnCurve (currentPositionInTime).xValue;
}
return getPointOnCurve (currentPositionInTime).yValue;
}
void BezierCurve::createVAO()
{
if(m_vaoCurve!=0 && m_vaoPoints!=0)
{
m_vaoCurve->unbind();
m_vaoCurve->removeVOA();
delete m_vaoCurve;
m_vaoPoints->unbind();
m_vaoPoints->removeVOA();
delete m_vaoPoints;
}
m_vaoPoints=VertexArrayObject::createVOA(GL_POINTS);
m_vaoPoints->bind();
unsigned int size=m_cp.size();
std::vector <Vec3> points(size);
for(unsigned int i=0;i<size;++i)
{
points[i].set(m_cp[i]);
}
m_vaoPoints->setData(m_numCP*sizeof(Vec3),points[0].m_x);
m_vaoPoints->setNumIndices(m_numCP);
m_vaoPoints->setVertexAttributePointer(0,3,GL_FLOAT,0,0);
m_vaoPoints->unbind();
m_vaoCurve=VertexArrayObject::createVOA(GL_LINE_STRIP);
m_vaoCurve->bind();
std::vector <Vec3> lines(m_lod);
for(int i=0;i!=m_lod;++i)
{
Real t = m_knots[m_numKnots-1] * i / (Real)(m_lod-1);
if(i==m_lod-1)
{
t-=0.001f;
}
lines[i].set(getPointOnCurve(t));
}
m_vaoCurve->setData(m_lod*sizeof(Vec3),lines[0].m_x);
m_vaoCurve->setNumIndices(m_lod);
m_vaoCurve->setVertexAttributePointer(0,3,GL_FLOAT,0,0);
m_vaoCurve->unbind();
}
void BezierCurve::createVAO() noexcept
{
if(m_vaoCurve!=0 && m_vaoPoints!=0)
{
m_vaoCurve->unbind();
m_vaoCurve->removeVAO();
//delete m_vaoCurve;
m_vaoPoints->unbind();
m_vaoPoints->removeVAO();
//delete m_vaoPoints;
}
m_vaoPoints=ngl::VAOFactory::createVAO("simpleVAO",GL_POINTS);
m_vaoPoints->bind();
size_t size=m_cp.size();
std::vector <Vec3> points(size);
for(size_t i=0;i<size;++i)
{
points[i].set(m_cp[i]);
}
m_vaoPoints->setData(SimpleVAO::VertexData(m_numCP*sizeof(Vec3),points[0].m_x));
m_vaoPoints->setNumIndices(m_numCP);
m_vaoPoints->setVertexAttributePointer(0,3,GL_FLOAT,0,0);
m_vaoPoints->unbind();
m_vaoCurve=ngl::VAOFactory::createVAO("simpleVAO",GL_LINE_STRIP);
m_vaoCurve->bind();
std::vector <Vec3> lines(m_lod);
for(unsigned int i=0;i!=m_lod;++i)
{
Real t = m_knots[m_numKnots-1] * i / static_cast<Real>(m_lod-1);
if(i==m_lod-1)
{
t-=0.001f;
}
lines[i].set(getPointOnCurve(t));
}
m_vaoCurve->setData(SimpleVAO::VertexData(m_lod*sizeof(Vec3),lines[0].m_x));
m_vaoCurve->setNumIndices(m_lod);
m_vaoCurve->setVertexAttributePointer(0,3,GL_FLOAT,0,0);
m_vaoCurve->unbind();
}
