C++ MFnNurbsCurve::tangent方法代码示例

MMatrix ropeGenerator::getMatrixFromParamCurve( MFnNurbsCurve &curveFn, float param, float twist, MAngle divTwist )
{
	MPoint pDivPos;
	//Here we control the tangent of the rope
	curveFn.getPointAtParam( param, pDivPos, MSpace::kWorld );
	MVector vTangent( curveFn.tangent( param, MSpace::kWorld ).normal() );
	MVector vNormal( curveFn.normal( param, MSpace::kWorld ).normal() );
	if ( MAngle( PrevNormal.angle( vNormal ) ).asDegrees() > 90 )
		//fprintf(stderr, "Angle = %g\n",MAngle( PrevNormal.angle( vNormal )).asDegrees());
		vNormal = vNormal * -1;
	PrevNormal = vNormal;
	//if ( vNormal.angle(  ) )
	MQuaternion qTwist( twist * divTwist.asRadians(), vTangent );
	vNormal = vNormal.rotateBy( qTwist );
	MVector vExtra( vNormal ^ vTangent );
	vNormal.normalize();
	vTangent.normalize();
	vExtra.normalize();
	double dTrans[4][4] ={
						{vNormal.x, vNormal.y, vNormal.z, 0.0f},
						{vTangent.x, vTangent.y, vTangent.z, 0.0f},
						{vExtra.x, vExtra.y, vExtra.z, 0.0f},
						{pDivPos.x,pDivPos.y,pDivPos.z, 1.0f}};
	MMatrix mTrans( dTrans );
	return mTrans;
}

void n_tentacle::computeSlerp(const MMatrix &matrix1, const MMatrix &matrix2, const MFnNurbsCurve &curve, double parameter, double blendRot, double iniLength, double curveLength, double stretch, double globalScale, int tangentAxis, MVector &outPos, MVector &outRot)
{
	//curveLength = curve.length()
        double lenRatio = iniLength / curveLength;

        MQuaternion quat1;
        quat1 = matrix1;

        MQuaternion quat2;
        quat2 = matrix2;

        this->bipolarityCheck(quat1, quat2);

    //need to adjust the parameter in order to maintain the length between elements, also for the stretch
		MVector tangent;
		MPoint pointAtParam;
		MPoint finaPos;
        double p = lenRatio * parameter * globalScale;
        double finalParam = p + (parameter - p) * stretch;
		
		if(curveLength * finalParam > curveLength)
		{
		  double lengthDiff = curveLength - (iniLength * parameter);

		  double param = curve.knot(curve.numKnots() - 1);
		  tangent = curve.tangent(param, MSpace::kWorld);
		  tangent.normalize();

		  curve.getPointAtParam(param, pointAtParam, MSpace::kWorld);
		  finaPos = pointAtParam;
		  pointAtParam += (- tangent) * lengthDiff;
		  //MGlobal::displayInfo("sdf");
		}
		else
		{
		  double param = curve.findParamFromLength(curveLength * finalParam);
		  tangent = curve.tangent(param, MSpace::kWorld);
		  tangent.normalize();
		  curve.getPointAtParam(param, pointAtParam, MSpace::kWorld);
		  
		}
                

        MQuaternion slerpQuat = slerp(quat1, quat2, blendRot);
        MMatrix slerpMatrix = slerpQuat.asMatrix();

        int axisId = abs(tangentAxis) - 1;
		MVector slerpMatrixYAxis = MVector(slerpMatrix(axisId, 0), slerpMatrix(axisId, 1), slerpMatrix(axisId, 2));
		slerpMatrixYAxis.normalize();
		if(tangentAxis < 0)
			slerpMatrixYAxis = - slerpMatrixYAxis;

		double angle = tangent.angle(slerpMatrixYAxis);
		MVector axis =  slerpMatrixYAxis ^ tangent;
		axis.normalize();

		MQuaternion rotationToSnapOnCurve(angle, axis);

		MQuaternion finalQuat = slerpQuat * rotationToSnapOnCurve;
		MEulerRotation finalEuler = finalQuat.asEulerRotation();

		outRot.x = finalEuler.x;
		outRot.y = finalEuler.y;
		outRot.z = finalEuler.z;
		outPos = pointAtParam;
}

MStatus splineSolverNode::preSolve()
{

    MStatus stat;
    setRotatePlane(false);
    setSingleChainOnly(true);
    setPositionOnly(false);
    //Get Handle
    MIkHandleGroup * handle_group = handleGroup();
    if (NULL == handle_group) {
        return MS::kFailure;
    }
    MObject handle = handle_group->handle( 0 );
    MDagPath handlePath = MDagPath::getAPathTo( handle );
    fnHandle.setObject( handlePath );
    //Get Curve
    MPlug inCurvePlug = fnHandle.findPlug( "inCurve" );
    MDataHandle curveHandle = inCurvePlug.asMDataHandle();
    MObject inputCurveObject = curveHandle.asNurbsCurveTransformed();
    curveFn.setObject( inputCurveObject );
    float initCurveLength = curveFn.length();
    MVector initNormal = curveFn.normal(0);
    MVector initTangent = curveFn.tangent(0);
    float stretchRatio = 1;
    // Get the position of the end_effector
    //
    MDagPath effectorPath;
    fnHandle.getEffector(effectorPath);
    tran.setObject( effectorPath );
    // Get the start joint position
    //
    MDagPath startJointPath;
    fnHandle.getStartJoint( startJointPath );
    joints.clear();
    //Get Joints
    while (true)
    {
        effectorPath.pop();
        joints.push_back( effectorPath );
        if (effectorPath == startJointPath)
            break;
    }
    std::reverse(joints.begin(), joints.end());
    if (!fnHandle.hasAttribute("str"))
    {
        //Add Custom Attributes to Handle
        MFnNumericAttribute fnAttr;
        MObject attr = fnAttr.create("stretchRatio", "str", MFnNumericData::kDouble, stretchRatio);
        fnAttr.setKeyable(1);
        fnAttr.setWritable(1);
        fnAttr.setMin(0);
        fnAttr.setMax(1);
        fnAttr.setHidden(0);
        fnAttr.setStorable(1);
        fnAttr.setReadable(1);
        fnHandle.addAttribute(attr, MFnDependencyNode::kLocalDynamicAttr);
        attr = fnAttr.create("anchorPosition", "ancp", MFnNumericData::kDouble, 0.0);
        fnAttr.setKeyable(1);
        fnAttr.setWritable(1);
        fnAttr.setMin(0);
        fnAttr.setMax(1);
        fnAttr.setHidden(0);
        fnAttr.setStorable(1);
        fnAttr.setReadable(1);
        fnHandle.addAttribute(attr, MFnDependencyNode::kLocalDynamicAttr);
        attr = fnAttr.create("curveLength", "cvLen", MFnNumericData::kDouble, initCurveLength);
        fnAttr.setKeyable(0);
        fnAttr.setWritable(1);
        fnAttr.setHidden(1);
        fnAttr.setStorable(1);
        fnAttr.setReadable(1);
        fnHandle.addAttribute(attr, MFnDependencyNode::kLocalDynamicAttr);
        attr = fnAttr.create("initNormal", "norm", MFnNumericData::k3Double);
        fnAttr.setDefault(initNormal.x, initNormal.y, initNormal.z);
        fnAttr.setKeyable(0);
        fnAttr.setWritable(1);
        fnAttr.setHidden(1);
        fnAttr.setStorable(1);
        fnAttr.setReadable(1);
        fnHandle.addAttribute(attr, MFnDependencyNode::kLocalDynamicAttr);
        attr = fnAttr.create("initTangent", "tang", MFnNumericData::k3Double);
        fnAttr.setDefault(initTangent.x, initTangent.y, initTangent.z);
        fnAttr.setKeyable(0);
        fnAttr.setWritable(1);
        fnAttr.setHidden(1);
        fnAttr.setStorable(1);
        fnAttr.setReadable(1);
        fnHandle.addAttribute(attr, MFnDependencyNode::kLocalDynamicAttr);
        attr = fnAttr.create("jointsLength", "jsLen", MFnNumericData::kDouble, getJointsTotalLenght());
        fnAttr.setKeyable(0);
        fnAttr.setWritable(1);
        fnAttr.setHidden(1);
        fnAttr.setStorable(1);
        fnAttr.setReadable(1);
        fnHandle.addAttribute(attr, MFnDependencyNode::kLocalDynamicAttr);
        attr = fnAttr.create("startTwist", "strtw", MFnNumericData::kDouble, 0.0);
        fnAttr.setKeyable(1);
        fnAttr.setWritable(1);
        fnAttr.setHidden(0);
        fnAttr.setStorable(1);
//.........这里部分代码省略.........