- Ifc: improved subsampling of curves for IfcSweptDiskSolid entities.

git-svn-id: https://assimp.svn.sourceforge.net/svnroot/assimp/trunk@1288 67173fc5-114c-0410-ac8e-9d2fd5bffc1f

code/IFCCurve.cpp

@@ -424,6 +424,12 @@ public:
 		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);

code/IFCGeometry.cpp

@@ -560,13 +560,19 @@ void ProcessSweptDiskSolid(const IfcSweptDiskSolid solid, TempMesh& result, Conv
 	result.verts.reserve(cnt_segments * samples * 4);
 	result.vertcnt.reserve((cnt_segments - 1) * samples);
 
-	// XXX while EstimateSampleCount() works well for non-composite curves, it
-	// fails badly for composite curves that require non-uniform sampling
-	// for good results.
-	IfcFloat p = solid.StartParam, delta = (solid.EndParam-solid.StartParam)/ (samples - 1);
+	std::vector<IfcVector3> points;
+	points.reserve(cnt_segments * samples);
 
+	TempMesh temp;
+	curve->SampleDiscrete(temp,solid.StartParam,solid.EndParam);
+	const std::vector<IfcVector3>& curve_points = temp.verts;
 
-	IfcVector3 current = curve->Eval(p);
+	if(curve_points.empty()) {
+		IFCImporter::LogWarn("curve evaluation yielded no points (IfcSweptDiskSolid)");
+		return;
+	}
+
+	IfcVector3 current = curve_points[0];
 	IfcVector3 previous = current;
 	IfcVector3 next;
 
@@ -575,15 +581,12 @@ void ProcessSweptDiskSolid(const IfcSweptDiskSolid solid, TempMesh& result, Conv
 	startvec.y = 1.0f;
 	startvec.z = 1.0f;
 
-	std::vector<IfcVector3> points;
-	points.reserve(cnt_segments * samples);
-
-	p += delta;
-
 	// generate circles at the sweep positions
-	for(size_t i = 0; i < samples; ++i, p += delta) {
+	for(size_t i = 0; i < samples; ++i) {
 
-		next = curve->Eval(p);
+		if(i != samples - 1) {
+			next = curve_points[i + 1];
+		}
 
 		// get a direction vector reflecting the approximate curvature (i.e. tangent)
 		IfcVector3 d = (current-previous) + (next-previous);

code/IFCLoader.cpp

@@ -154,7 +154,7 @@ void IFCImporter::SetupProperties(const Importer* pImp)
 	settings.skipCurveRepresentations = pImp->GetPropertyBool(AI_CONFIG_IMPORT_IFC_SKIP_CURVE_REPRESENTATIONS,true);
 	settings.useCustomTriangulation = pImp->GetPropertyBool(AI_CONFIG_IMPORT_IFC_CUSTOM_TRIANGULATION,true);
 
-	settings.conicSamplingAngle = 10.f;
+	settings.conicSamplingAngle = 5.f;
 	settings.skipAnnotations = true;
 }