assimp/code/IFCCurve.cpp

/*
Open Asset Import Library (assimp)
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*/

/** @file  IFCProfile.cpp
 *  @brief Read profile and curves entities from IFC files
 */

#include "AssimpPCH.h"

#ifndef ASSIMP_BUILD_NO_IFC_IMPORTER
#include "IFCUtil.h"

namespace Assimp {
	namespace IFC {
		namespace {


// --------------------------------------------------------------------------------
// Conic is the base class for Circle and Ellipse
// --------------------------------------------------------------------------------
class Conic : public Curve
{

public:

	// --------------------------------------------------
	Conic(const IfcConic& entity, ConversionData& conv) 
		: Curve(entity,conv)
	{
		IfcMatrix4 trafo;
		ConvertAxisPlacement(trafo,*entity.Position,conv);

		// for convenience, extract the matrix rows
		location = IfcVector3(trafo.a4,trafo.b4,trafo.c4);
		p[0] = IfcVector3(trafo.a1,trafo.b1,trafo.c1);
		p[1] = IfcVector3(trafo.a2,trafo.b2,trafo.c2);
		p[2] = IfcVector3(trafo.a3,trafo.b3,trafo.c3);
	}

public:

	// --------------------------------------------------
	bool IsClosed() const {
		return true;
	}
	
	// --------------------------------------------------
	size_t EstimateSampleCount(IfcFloat a, IfcFloat b) const {
		ai_assert(InRange(a) && InRange(b));

		a *= conv.angle_scale;
		b *= conv.angle_scale;

		a = std::fmod(a,static_cast<IfcFloat>( AI_MATH_TWO_PI ));
		b = std::fmod(b,static_cast<IfcFloat>( AI_MATH_TWO_PI ));
		const IfcFloat setting = static_cast<IfcFloat>( AI_MATH_PI * conv.settings.conicSamplingAngle / 180.0 );
		return static_cast<size_t>( std::ceil(abs( b-a)) / setting);
	}

	// --------------------------------------------------
	ParamRange GetParametricRange() const {
		return std::make_pair(static_cast<IfcFloat>( 0. ), static_cast<IfcFloat>( AI_MATH_TWO_PI / conv.angle_scale ));
	}

protected:
	IfcVector3 location, p[3];
};


// --------------------------------------------------------------------------------
// Circle
// --------------------------------------------------------------------------------
class Circle : public Conic
{

public:

	// --------------------------------------------------
	Circle(const IfcCircle& entity, ConversionData& conv) 
		: Conic(entity,conv)
		, entity(entity)
	{
	}

public:

	// --------------------------------------------------
	IfcVector3 Eval(IfcFloat u) const {
		u = -conv.angle_scale * u;
		return location + static_cast<IfcFloat>(entity.Radius)*(static_cast<IfcFloat>(std::cos(u))*p[0] +
			static_cast<IfcFloat>(std::sin(u))*p[1]);
	}

private:
	const IfcCircle& entity;
};


// --------------------------------------------------------------------------------
// Ellipse
// --------------------------------------------------------------------------------
class Ellipse : public Conic
{

public:

	// --------------------------------------------------
	Ellipse(const IfcEllipse& entity, ConversionData& conv) 
		: Conic(entity,conv)
		, entity(entity)
	{
	}

public:

	// --------------------------------------------------
	IfcVector3 Eval(IfcFloat u) const {
		u = -conv.angle_scale * u;
		return location + static_cast<IfcFloat>(entity.SemiAxis1)*static_cast<IfcFloat>(std::cos(u))*p[0] +
			static_cast<IfcFloat>(entity.SemiAxis2)*static_cast<IfcFloat>(std::sin(u))*p[1];
	}

private:
	const IfcEllipse& entity;
};


// --------------------------------------------------------------------------------
// Line
// --------------------------------------------------------------------------------
class Line : public Curve 
{

public:

	// --------------------------------------------------
	Line(const IfcLine& entity, ConversionData& conv) 
		: Curve(entity,conv)
		, entity(entity)
	{
		ConvertCartesianPoint(p,entity.Pnt);
		ConvertVector(v,entity.Dir);
	}

public:

	// --------------------------------------------------
	bool IsClosed() const {
		return false;
	}

	// --------------------------------------------------
	IfcVector3 Eval(IfcFloat u) const {
		return p + u*v;
	}

	// --------------------------------------------------
	size_t EstimateSampleCount(IfcFloat a, IfcFloat b) const {
		ai_assert(InRange(a) && InRange(b));
		// two points are always sufficient for a line segment
		return a==b ? 1 : 2;
	}


	// --------------------------------------------------
	void SampleDiscrete(TempMesh& out,IfcFloat a, IfcFloat b) const
	{
		ai_assert(InRange(a) && InRange(b));
	
		if (a == b) {
			out.verts.push_back(Eval(a));
			return;
		}
		out.verts.reserve(out.verts.size()+2);
		out.verts.push_back(Eval(a));
		out.verts.push_back(Eval(b));
	}

	// --------------------------------------------------
	ParamRange GetParametricRange() const {
		const IfcFloat inf = std::numeric_limits<IfcFloat>::infinity();

		return std::make_pair(-inf,+inf);
	}

private:
	const IfcLine& entity;
	IfcVector3 p,v;
};

// --------------------------------------------------------------------------------
// CompositeCurve joins multiple smaller, bounded curves
// --------------------------------------------------------------------------------
class CompositeCurve : public BoundedCurve 
{

	typedef std::pair< boost::shared_ptr< BoundedCurve >, bool > CurveEntry;

public:

	// --------------------------------------------------
	CompositeCurve(const IfcCompositeCurve& entity, ConversionData& conv) 
		: BoundedCurve(entity,conv)
		, entity(entity)
		, total()
	{
		curves.reserve(entity.Segments.size());
		BOOST_FOREACH(const IfcCompositeCurveSegment& curveSegment,entity.Segments) {
			// according to the specification, this must be a bounded curve
			boost::shared_ptr< Curve > cv(Curve::Convert(curveSegment.ParentCurve,conv));
			boost::shared_ptr< BoundedCurve > bc = boost::dynamic_pointer_cast<BoundedCurve>(cv);

			if (!bc) {
				IFCImporter::LogError("expected segment of composite curve to be a bounded curve");
				continue;
			}

			if ( (std::string)curveSegment.Transition != "CONTINUOUS" ) {
				IFCImporter::LogDebug("ignoring transition code on composite curve segment, only continuous transitions are supported");
			}

			curves.push_back( CurveEntry(bc,IsTrue(curveSegment.SameSense)) );
			total += bc->GetParametricRangeDelta();
		}

		if (curves.empty()) {
			throw CurveError("empty composite curve");
		}
	}

public:

	// --------------------------------------------------
	IfcVector3 Eval(IfcFloat u) const {
		if (curves.empty()) {
			return IfcVector3();
		}

		IfcFloat acc = 0;
		BOOST_FOREACH(const CurveEntry& entry, curves) {
			const ParamRange& range = entry.first->GetParametricRange();
			const IfcFloat delta = abs(range.second-range.first);
			if (u < acc+delta) {
				return entry.first->Eval( entry.second ? (u-acc) + range.first : range.second-(u-acc));
			}

			acc += delta;
		}
		// clamp to end
		return curves.back().first->Eval(curves.back().first->GetParametricRange().second);
	}

	// --------------------------------------------------
	size_t EstimateSampleCount(IfcFloat a, IfcFloat b) const {
		ai_assert(InRange(a) && InRange(b));
		size_t cnt = 0;

		IfcFloat acc = 0;
		BOOST_FOREACH(const CurveEntry& entry, curves) {
			const ParamRange& range = entry.first->GetParametricRange();
			const IfcFloat delta = abs(range.second-range.first);
			if (a <= acc+delta && b >= acc) {
				const IfcFloat at =  std::max(static_cast<IfcFloat>( 0. ),a-acc), bt = std::min(delta,b-acc);
				cnt += entry.first->EstimateSampleCount( entry.second ? at + range.first : range.second - bt, entry.second ? bt + range.first : range.second - at );
			}

			acc += delta;
		}

		return cnt;
	}

	// --------------------------------------------------
	void SampleDiscrete(TempMesh& out,IfcFloat a, IfcFloat b) const
	{
		ai_assert(InRange(a) && InRange(b));

		const size_t cnt = EstimateSampleCount(a,b);
		out.verts.reserve(out.verts.size() + cnt);

		BOOST_FOREACH(const CurveEntry& entry, curves) {
			const size_t cnt = out.verts.size();
			entry.first->SampleDiscrete(out);

			if (!entry.second && cnt != out.verts.size()) {
				std::reverse(out.verts.begin()+cnt,out.verts.end());
			}
		}
	}

	// --------------------------------------------------
	ParamRange GetParametricRange() const {
		return std::make_pair(static_cast<IfcFloat>( 0. ),total);
	}

private:
	const IfcCompositeCurve& entity;
	std::vector< CurveEntry > curves;

	IfcFloat total;
};


// --------------------------------------------------------------------------------
// TrimmedCurve can be used to trim an unbounded curve to a bounded range
// --------------------------------------------------------------------------------
class TrimmedCurve : public BoundedCurve 
{

public:

	// --------------------------------------------------
	TrimmedCurve(const IfcTrimmedCurve& entity, ConversionData& conv) 
		: BoundedCurve(entity,conv)
		, entity(entity)
		, ok()
	{
		base = boost::shared_ptr<const Curve>(Curve::Convert(entity.BasisCurve,conv));

		typedef boost::shared_ptr<const STEP::EXPRESS::DataType> Entry;
	
		// for some reason, trimmed curves can either specify a parametric value
		// or a point on the curve, or both. And they can even specify which of the
		// two representations they prefer, even though an information invariant
		// claims that they must be identical if both are present.
		// oh well.
		bool have_param = false, have_point = false;
		IfcVector3 point;
		BOOST_FOREACH(const Entry sel,entity.Trim1) {
			if (const EXPRESS::REAL* const r = sel->ToPtr<EXPRESS::REAL>()) {
				range.first = *r;
				have_param = true;
				break;
			}
			else if (const IfcCartesianPoint* const r = sel->ResolveSelectPtr<IfcCartesianPoint>(conv.db)) {
				ConvertCartesianPoint(point,*r);
				have_point = true;
			}
		}
		if (!have_param) {
			if (!have_point || !base->ReverseEval(point,range.first)) {
				throw CurveError("IfcTrimmedCurve: failed to read first trim parameter, ignoring curve");
			}
		}
		have_param = false, have_point = false;
		BOOST_FOREACH(const Entry sel,entity.Trim2) {
			if (const EXPRESS::REAL* const r = sel->ToPtr<EXPRESS::REAL>()) {
				range.second = *r;
				have_param = true;
				break;
			}
			else if (const IfcCartesianPoint* const r = sel->ResolveSelectPtr<IfcCartesianPoint>(conv.db)) {
				ConvertCartesianPoint(point,*r);
				have_point = true;
			}
		}
		if (!have_param) {
			if (!have_point || !base->ReverseEval(point,range.second)) {
				throw CurveError("IfcTrimmedCurve: failed to read second trim parameter, ignoring curve");
			}
		}

		agree_sense = IsTrue(entity.SenseAgreement);
		if( !agree_sense ) {
			std::swap(range.first,range.second);
		}

		// "NOTE In case of a closed curve, it may be necessary to increment t1 or t2
		// by the parametric length for consistency with the sense flag."
		if (base->IsClosed()) {
			if( range.first > range.second ) {
				range.second += base->GetParametricRangeDelta();
			}
		}

		maxval = range.second-range.first;
		ai_assert(maxval >= 0);
	}

public:

	// --------------------------------------------------
	IfcVector3 Eval(IfcFloat p) const {
		ai_assert(InRange(p));
		return base->Eval( TrimParam(p) );
	}

	// --------------------------------------------------
	size_t EstimateSampleCount(IfcFloat a, IfcFloat b) const {
		ai_assert(InRange(a) && InRange(b));
		return base->EstimateSampleCount(TrimParam(a),TrimParam(b));
	}

	// --------------------------------------------------
	void SampleDiscrete(TempMesh& out,IfcFloat a,IfcFloat b) const {
		ai_assert(InRange(a) && InRange(b));
		return base->SampleDiscrete(out,TrimParam(a),TrimParam(b));
	}

	// --------------------------------------------------
	ParamRange GetParametricRange() const {
		return std::make_pair(static_cast<IfcFloat>( 0. ),maxval);
	}

private:

	// --------------------------------------------------
	IfcFloat TrimParam(IfcFloat f) const {
		return agree_sense ? f + range.first :  range.second - f;
	}


private:
	const IfcTrimmedCurve& entity;
	ParamRange range;
	IfcFloat maxval;
	bool agree_sense;
	bool ok;

	boost::shared_ptr<const Curve> base;
};


// --------------------------------------------------------------------------------
// PolyLine is a 'curve' defined by linear interpolation over a set of discrete points
// --------------------------------------------------------------------------------
class PolyLine : public BoundedCurve 
{

public:

	// --------------------------------------------------
	PolyLine(const IfcPolyline& entity, ConversionData& conv) 
		: BoundedCurve(entity,conv)
		, entity(entity)
	{
		points.reserve(entity.Points.size());

		IfcVector3 t;
		BOOST_FOREACH(const IfcCartesianPoint& cp, entity.Points) {
			ConvertCartesianPoint(t,cp);
			points.push_back(t);
		}
	}

public:

	// --------------------------------------------------
	IfcVector3 Eval(IfcFloat p) const {
		ai_assert(InRange(p));
		
		const size_t b = static_cast<size_t>(std::floor(p));
		if (b == points.size()-1) {
			return points.back();
		}

		const IfcFloat d = p-static_cast<IfcFloat>(b);
		return points[b+1] * d + points[b] * (static_cast<IfcFloat>( 1. )-d);
	}

	// --------------------------------------------------
	size_t EstimateSampleCount(IfcFloat a, IfcFloat b) const {
		ai_assert(InRange(a) && InRange(b));
		return static_cast<size_t>( std::ceil(b) - std::floor(a) );
	}

	// --------------------------------------------------
	ParamRange GetParametricRange() const {
		return std::make_pair(static_cast<IfcFloat>( 0. ),static_cast<IfcFloat>(points.size()-1));
	}

private:
	const IfcPolyline& entity;
	std::vector<IfcVector3> points;
};


} // anon


// ------------------------------------------------------------------------------------------------
Curve* Curve :: Convert(const IFC::IfcCurve& curve,ConversionData& conv) 
{
	if(curve.ToPtr<IfcBoundedCurve>()) {
		if(const IfcPolyline* c = curve.ToPtr<IfcPolyline>()) {
			return new PolyLine(*c,conv);
		}
		if(const IfcTrimmedCurve* c = curve.ToPtr<IfcTrimmedCurve>()) {
			return new TrimmedCurve(*c,conv);
		}
		if(const IfcCompositeCurve* c = curve.ToPtr<IfcCompositeCurve>()) {
			return new CompositeCurve(*c,conv);
		}
		//if(const IfcBSplineCurve* c = curve.ToPtr<IfcBSplineCurve>()) {
		//	return new BSplineCurve(*c,conv);
		//}
	}

	if(curve.ToPtr<IfcConic>()) {
		if(const IfcCircle* c = curve.ToPtr<IfcCircle>()) {
			return new Circle(*c,conv);
		}
		if(const IfcEllipse* c = curve.ToPtr<IfcEllipse>()) {
			return new Ellipse(*c,conv);
		}
	}

	if(const IfcLine* c = curve.ToPtr<IfcLine>()) {
		return new Line(*c,conv);
	}

	// XXX OffsetCurve2D, OffsetCurve3D not currently supported
	return NULL;
}

#ifdef ASSIMP_BUILD_DEBUG
// ------------------------------------------------------------------------------------------------
bool Curve :: InRange(IfcFloat u) const 
{
	const ParamRange range = GetParametricRange();
	if (IsClosed()) {
		return true;
		//ai_assert(range.first != std::numeric_limits<IfcFloat>::infinity() && range.second != std::numeric_limits<IfcFloat>::infinity());
		//u = range.first + std::fmod(u-range.first,range.second-range.first);
	}
	const IfcFloat epsilon = 1e-5;
	return u - range.first > -epsilon && range.second - u > -epsilon;
}
#endif 

// ------------------------------------------------------------------------------------------------
IfcFloat Curve :: GetParametricRangeDelta() const
{
	const ParamRange& range = GetParametricRange();
	return abs(range.second - range.first);
}

// ------------------------------------------------------------------------------------------------
size_t Curve :: EstimateSampleCount(IfcFloat a, IfcFloat b) const
{
	ai_assert(InRange(a) && InRange(b));

	// arbitrary default value, deriving classes should supply better suited values
	return 16;
}

// ------------------------------------------------------------------------------------------------
IfcFloat RecursiveSearch(const Curve* cv, const IfcVector3& val, IfcFloat a, IfcFloat b, unsigned int samples, IfcFloat threshold, unsigned int recurse = 0, unsigned int max_recurse = 15)
{
	ai_assert(samples>1);

	const IfcFloat delta = (b-a)/samples, inf = std::numeric_limits<IfcFloat>::infinity();
	IfcFloat min_point[2] = {a,b}, min_diff[2] = {inf,inf};
	IfcFloat runner = a;

	for (unsigned int i = 0; i < samples; ++i, runner += delta) {
		const IfcFloat diff = (cv->Eval(runner)-val).SquareLength();
		if (diff < min_diff[0]) {
			min_diff[1] = min_diff[0];
			min_point[1] = min_point[0];

			min_diff[0] = diff;
			min_point[0] = runner;
		}
		else if (diff < min_diff[1]) {
			min_diff[1] = diff;
			min_point[1] = runner;
		}
	}

	ai_assert(min_diff[0] != inf && min_diff[1] != inf);
	if ( std::fabs(a-min_point[0]) < threshold || recurse >= max_recurse) {
		return min_point[0];
	}

	// fix for closed curves to take their wrap-over into account
	if (cv->IsClosed() && std::fabs(min_point[0]-min_point[1]) > cv->GetParametricRangeDelta()*0.5  ) {
		const Curve::ParamRange& range = cv->GetParametricRange();
		const IfcFloat wrapdiff = (cv->Eval(range.first)-val).SquareLength();

		if (wrapdiff < min_diff[0]) {
			const IfcFloat t = min_point[0];
			min_point[0] = min_point[1] > min_point[0] ? range.first : range.second;
			 min_point[1] = t;
		}
	}

	return RecursiveSearch(cv,val,min_point[0],min_point[1],samples,threshold,recurse+1,max_recurse);
}

// ------------------------------------------------------------------------------------------------
bool Curve :: ReverseEval(const IfcVector3& val, IfcFloat& paramOut) const
{
	// note: the following algorithm is not guaranteed to find the 'right' parameter value
	// in all possible cases, but it will always return at least some value so this function
	// will never fail in the default implementation.

	// XXX derive threshold from curve topology
	const IfcFloat threshold = 1e-4f;
	const unsigned int samples = 16;

	const ParamRange& range = GetParametricRange();
	paramOut = RecursiveSearch(this,val,range.first,range.second,samples,threshold);

	return true;
}

// ------------------------------------------------------------------------------------------------
void Curve :: SampleDiscrete(TempMesh& out,IfcFloat a, IfcFloat b) const
{
	ai_assert(InRange(a) && InRange(b));

	const size_t cnt = std::max(static_cast<size_t>(0),EstimateSampleCount(a,b));
	out.verts.reserve( out.verts.size() + cnt );

	IfcFloat p = a, delta = (b-a)/cnt;
	for(size_t i = 0; i < cnt; ++i, p += delta) {
		out.verts.push_back(Eval(p));
	}
}

// ------------------------------------------------------------------------------------------------
bool BoundedCurve :: IsClosed() const
{
	return false;
}

// ------------------------------------------------------------------------------------------------
void BoundedCurve :: SampleDiscrete(TempMesh& out) const
{
	const ParamRange& range = GetParametricRange();
	ai_assert(range.first != std::numeric_limits<IfcFloat>::infinity() && range.second != std::numeric_limits<IfcFloat>::infinity());

	return SampleDiscrete(out,range.first,range.second);
}

} // IFC
} // Assimp

#endif // ASSIMP_BUILD_NO_IFC_IMPORTER