SDK MaxScript Function Publishing

[MehdiZangenehBar]

I just want to recreate InterpCurve3D in c++ and publish it to the MaxScript. this is the c# version:

using Autodesk.Max;

namespace MyProject
{
    public static class MyClass
    {
        static IGlobal g = GlobalInterface.Instance;
        static IInterface14 i = g.COREInterface14;
        public static IPoint3 InterpCurve3D(uint handle,float param)
        {
            IINode node = i.GetINodeByHandle(handle);
            IObject obj = node.EvalWorldState(g.COREInterface.Time, true).Obj;
            ISplineShape shape = obj as ISplineShape;
            return shape.InterpCurve3D(0, 0, param, 0);
        }
    }
}

and this is the c++ version that I'm trying to create:

#include <maxscript/maxscript.h>
#include <maxscript/macros/define_instantiation_functions.h>
#include <maxscript/foundation/numbers.h>

def_visible_primitive(SampleFunction, "SampleFunction");
Value*
SampleFunction_cf(Value** arg_list, int count)
{
	INode* node = arg_list[0]->to_node;
	float param = arg_list[0]->to_float;
	ReferenceTarget* ref = node->GetObjectRef();
	TimeValue t = GetCOREInterface()->GetTime();
	ObjectState os = node->EvalWorldState(t);
	ShapeObject* spline = (ShapeObject*)os.obj;
	Point3 result = spline->InterpCurve3D(t,1,param,0);
}

In "IntervalArray" example, I saw return_value_tls for returning value, but actually I don't know how I can use it. I'm using VS 2017, Max 2018

[istan · Accepted solution]

return new Point3Value(result );

pretty simple..

[MehdiZangenehBar]

Not working...

Point3Value >> expected a type specifier

[istan]

3dmath.h included?

[MehdiZangenehBar]

Now works, Thank You. but I still got errors on build. this is my code:

#include <maxscript/maxscript.h>
#include <maxscript/macros/define_instantiation_functions.h>
#include <maxscript/foundation/3dmath.h>

def_visible_primitive(SampleFunction, "SampleFunction");
Value*
SampleFunction_cf(Value** arg_list, int count)
{
	INode* node = arg_list[0]->to_node;
	float param = arg_list[0]->to_float;
	ReferenceTarget* ref = node->GetObjectRef();
	TimeValue t = GetCOREInterface()->GetTime();
	ObjectState os = node->EvalWorldState(t);
	ShapeObject* spline = (ShapeObject*)os.obj;
	Point3 result = spline->InterpCurve3D(t,1,param,0);
	return new Point3Value(result);
}

Errors:

qualified name is not allowed in member declaration

[denisT.MaxDoctor · Accepted solution]

	INode* node = arg_list[0]->to_node();
	float param = arg_list[1]->to_float();

[MehdiZangenehBar]

Finally I build the code :), Thank You!

[MehdiZangenehBar]

I'm new to c++ and I have some beginner questions:

Why I should use Point3Value instead of Point3?

Why IntervalArray used return_value_tls instead of return?

[denisT.MaxDoctor · Accepted solution]

#1 every published function has to return MXS Value... Point3Value is a wrapper for c++ SDK Point3 

#2 return_value_tls is special macros to return mxs value and free allocated for local values memory. in your case you don't have to do it   

[istan]

As you wrote you are a C++ beginner: Honestly, just a tip: I would not start learning C++ by writing plugins for 3dsmax.

[MehdiZangenehBar]

You right, I should learn basic of C++ first, But actually at the moment I don't want to work on large projects, I just want to expose some necessary functions to MaxScript. So this challenges will encourage me to learn C++ and helps me to understand what I should learn first.

[MehdiZangenehBar]

When I move the line

#include <maxscript/foundation/3dmath.h>

Before

#include <maxscript/macros/define_instantiation_functions.h>

My function in MaxScript will be undefined. So my question is include priority matters?

[MehdiZangenehBar · Accepted solution]

I'm so exited! it works very well so far:

#include <maxscript/maxscript.h>
#include <maxscript/foundation/3dmath.h>
#include <maxscript/macros/define_instantiation_functions.h>

def_visible_primitive(ShapeInterp, "ShapeInterp");
Value* ShapeInterp_cf(Value **arg_list, int count)
{
	INode* node = arg_list[0]->to_node();
	int curveIndex = arg_list[1]->to_int();
	float percent = arg_list[2]->to_float();
	int type = arg_list[3]->to_int();
	TimeValue t = GetCOREInterface()->GetTime();
	ShapeObject* shape = (ShapeObject*)node->EvalWorldState(t).obj;
	Point3 result = shape->InterpCurve3D(t, curveIndex-1, percent/(float)100,type)*node->GetObjectTM(t);
	return new Point3Value(result);
}

Compare to the Max version, has great benefits:

1. Works on any shape not only splines.
2. Works at WorldState (Max version only works on base object not modifiers).
3. It's not completed yet, but so far works faster(1.6 times) than default version.

Next I want to add argument cheking and default values.