Using code from tutorials and plagarism

[Amuscaria]

I have a question regarding usage of code in from online tutorials. I'm currently working on my a masters thesis project and I'm learning to use Unity for it. I've looked up forum how-tos online and from tutorials on how to do certain things in the engine using C#. I've modified the code a bit for my own uses, but most of it is the same (the basic structure is identical). Is it considered plagiarizing if I used the code in the final product (with citations) and then use that product for future education purposes? I'm not familiar with what is and is not considered plagiarizing when it comes to computer code, since its a functional product.

[Rachael]

Fair use is intentionally a bit broader when it comes to educational purposes - and that includes a masters thesis. As long as you cite your sources you should be okay.

Just don't base the entire thing on one tutorial, or make it all nothing but tutorial code. Make it your own.

[nazakomu]

Just don't base the entire thing on one tutorial, or make it all nothing but tutorial code. Make it your own.

Agreed 100 percent! It's okay to be doing it at first but you'll almost never get anywhere if you don't spend time and dedication on doing your own code and finding your own method of doing things in coding.

I can admittedly already say the same thing for something like ZScript, where I spent my first month and a half looking at others' code and trying to always make something similar and eventually I got the hang of it enough to make my own without any inspection on others' code.

[Amuscaria]

I'll have to get a firmer grasp of C#'s syntax before coding my own stuff. I'm currently not even sure how to look up help because I don't know the proper terminology to search for. For example, what does it mean when you have "something.something-else"? (i.e. Time.deltatime) What does the period between the two words denote? I know what its doing. I just don't know if that's just the coders' choice of aesthetic, or it actually has significance.

For example, the following:

Code: Select all

void HandleInput () 
	{
		Ray inputRay = Camera.main.ScreenPointToRay(Input.mousePosition);
		RaycastHit hit;
		
		if (Physics.Raycast(inputRay, out hit)) 
		{
			MeshDeformer deformer = hit.collider.GetComponent<MeshDeformer>();
			if (deformer) 
			{
				Vector3 point = hit.point;
				point += hit.normal * forceOffset;
				deformer.AddDeformingForce(point, force);
			}
		}
	}

I know the code is using a raycast from the viewing camera pointing at the mouse position on the screen and its saving that as the Raycast variable "hit", and using that to deform the mesh according to the force and the forceOffset set by the user. But my understanding of the code stops at the if statement. I have no idea what "if (Physics.Raycast(inputRay, out hit))" means. Im used to comparison operations such as <,>, <=, etc. Not what I'm seeing here.

[Rachael]

The period denotes "member" - basically the syntax is Class.member. Member can either be a function or a variable or a pointer (well, in C++, anyway, not sure about C#).

So saying hit.point is basically calling the class "hit" which is one of the classes that will be leaving the function as a return value - and ".point" is asking exactly where did this hit occur.

Likewise, deformer.AddDeformingForce is calling the class member function AddDeformingForce of the class "deformer".

The easiest way to figure out what class has what functions (aka methods) or variables is to look up the class definition, itself.

[phantombeta]

@Amuscaria
1) That period between two words is the member-access operator. "foo.bar" accesses the "bar" member of the class or struct "foo".
2) See that "out" before the "hit" argument there? That means that argument is actually used for output, not input. The function probably returns a bool so you can use it like this, while giving you the actual output of the function via an out argument.
As for why there's no comparison operator in there, comparison operators do a comparison between two arguments, and if the arguments pass the comparison, they return true. If not, they return false. All "if" does is check if a bool is true and execute the code in the following block if it is.
Some variable types also usually automatically convert to bool when used where a bool is required/requested.

I recommend reading some general C# books. The C# Yellow Book seems pretty good.
I didn't read said book when learning C#, but after coming back to it from D (which is more flexible and powerful, while being somewhat easier to use than C#, IMO), I had to look some stuff up, and I read that book for figuring out how to do some things I needed to do.
You can get it here.

@Rachael
It can indeed be any of those, although pointers are not used very often in C#* AFAIK.

* You actually have to enable the "unsafe" context in the compilation options to even be able to use them, and you have to put them inside an "unsafe" block. Using said "unsafe" block also disables things like array index range-checking, IIRC.

[Amuscaria]

Ah, Ok.

Haven't look into C# that much yet. Watched a couple of "crash course" tutorials on YT so far. Started a couple of weeks ago because I wanted/needed Unity to make some ultrasound simulator for education purposes in the hospital. I've only taken 1 semester of CS101 C++ years ago to fill an Engineering requirement, so we haven't gotten into members or classes yet (at least not in depth). Think the farthest we go was pointers, and barely even that.

I'll take a look at the books recommended. Thanks!

[NeuralStunner]

For a current project, I wasn't going to be able to use a segment of bugfix code provided by someone else (due to their use restrictions). However, by understanding the bug I was able to write my own fix implementation. (It still seemed polite to credit those authors for identifying the problem.)

[Amuscaria]

here's the modified code from yesterday for context:

---

Code: Select all

using UnityEngine;
public class MeshDeformerInput : MonoBehaviour 
{
	public float force = 10f;
	public float forceOffset = 0.1f;
	private Vector3 reverseVector = new Vector3 (1, 1, 1);
		void Update () 
	{
		if (Input.GetMouseButton(0)) 
		{
			HandleInput();
		}
	}
		void HandleInput ()
	{
		Ray inputRay = Camera.main.ScreenPointToRay(Input.mousePosition);
		RaycastHit hit;
		if (Physics.Raycast(inputRay, out hit))
		{
			MeshDeformer deformer = hit.collider.GetComponent<MeshDeformer>();
			if (deformer)
			{
				Vector3 point = Vector3.Scale(hit.point, reverseVector); // do reversal here
				point += hit.normal * forceOffset;
				deformer.AddDeformingForce(point, force);
			}
		}
	}
}

In the original code, the main camera casts a Raycast wherever your mouse cursor is pointing. If it detects vertex, it pushes the vertex away from the camera, normal to the direction of the raycast (i think). There is an offset variable that applies this vertex to any nearby ones as well. What it does basicallt is it pushes the surface of the mesh in, and all of the vertices next to the target vertex away from it. I wanted to reverse it so that the vertices are dragged towards the target while still pushing the mesh inwards. I'd figured that if I reversed the magnitude of the vector3's X and Y values, without touching the Z, it would give me that effect. But the way I have it set up not doesn't seem to do anything. If I have a negative value in ANY of the vector3 XYZ, it stops the script from doing anything at all (at least as far as I can tell). I have no idea why. I'm asking the Unity forums regarding this.

More syntax questions.

What does the stuff in the "out" mean in the following example:

Code: Select all

if (Physics.Raycast(inputRay, out hit)

I THINK it's setting the 1st and 2nd parameters for Physics.Raycast to the vector3 values of "InputRay" and "hit", respectively. I'm not sure what the "out" does, though.

I also don't know what the <> backets mean in the following (heck, I don't know what that entire line means):

Code: Select all

MeshDeformer deformer = hit.collider.GetComponent<MeshDeformer>()

[Rachael]

"Out" simply means that you are expected to pass a variable into the function and the function is allowed to modify it and send it back (sort of as a poor-man's "extra return value"). This seems to be something specific to C# - C/C++ does this by simply using pointers. The calling function is then able to make use of the modified variable - i.e. if a function is defined as something(out a) and "a" changes to 4 inside the function, then calling something(i) causes i to become 4 in the parent function.

As for the <>'s I know that in C++ they are for specific types of type-casts. I would assume that is the case here, as well - it is forcing the return value or variable to be a certain type, regardless of the type it may have previously been. Sometimes this is an actually functional cast - but other times it is used simply for syntax enforcement in order to help reduce the amount of errors in the code.

[phantombeta]

"out" is the keyword for output arguments.
"hit" there is still being used for outputting the function's actual output, and the return value is being used for checking whether the function's output is valid.
And the <> brackets are Generics stuff. Somewhat complex, and you shouldn't try to mess with it yet, probably.

Also, I'd recommend reading that book first before trying to code in C#. It explains what you're asking about. (there's a free ebook version on that site, btw.)

@Rachael
Nope. "<>" in C# is used for templates and template related stuff.
Oh and unlike in C++ templates are actually usable.

Thank <insert deity of your choice here> for Generics. Having to make a billion copies of a function just to have it accept different variable types is dumb.
I wish C#'s templates were as flexible as D's, though. D template are super flexible and waaaay easier to use than C# templates.

[Rachael]

Ah, thanks for the correction then. I marked it through.

[Gutawer]

"Out" simply means that you are expected to pass a variable into the function and the function is allowed to modify it and send it back (sort of as a poor-man's "extra return value"). This seems to be something specific to C# - C/C++ does this by simply using pointers.

Worth noting that C++ can do this via something like

Code: Select all

void myFunc(int& myVal) {
}

to avoid pointers altogether in that example (a variable passed in this way doesn't need to be derefenced like a pointer, and can be used just like a normal variable). This is actually more similar to C# out than pointers.

[Amuscaria]

I need some help with debugging my if statement logic.

I wanted to make a condition where a probe cannot be rotated to a angle greater than the parent's base angle +/- ~81 (0.45f) degrees (for some reason the angle is stored from -1.0 to 1.0). The parent orients itself based on the normal of a plane that it moves around on. So I made the the following nested if statements. Everything else works except the limiting section. It just rotates as much as I want it to. What am I doing wrong with the marked with "<<<<<---this line" if statement?

Code: Select all

void TiltFunction () //tilts the probe 
	{
		if (transform.rotation.z <= transform.parent.rotation.z+0.45f || transform.rotation.z >= transform.parent.rotation.z-0.45f) //limits the tilt to +/-60 degrees <<<<<<---this line
		{
			if (Input.GetKey("w"))
			{
				transform.Rotate(0,0,tiltSpeed);
			}
			if (Input.GetKey("s"))
			{
				transform.Rotate(0,0,-tiltSpeed);
			}
		}
		Debug.Log("Parent rotation is " + transform.parent.rotation.z);
		Debug.Log("Probe rotation is " + transform.rotation.z);
	}