Develop Reference

A-Star Unity 2D: How to find vector2 coordinates of AI's current waypoint?

[Using A-Star project] Hi. So the problem is in the title basically. I have a top-down game in which the enemy should face the direction they're going. I've tried:
To calculate Enemy's force of it's RigidBody in FixedUpdate
To calculate the vector from enemy to target.
In the first instance Enemy changes its animation states too quickly, every fixed frame there's a new force applied (especially annoying when the AI is close to target).
In the second Enemy always faces its target ignoring any obstacles. It's wallhacking, if you will.
To solve this bastard I decided to find AI's current waypoint and I do not know how to do that. I've found steeringTarget method in A-Star's documentation, but I couldn't figure out how to implement it.
I would REALLY appreciate any help. Thanks in advance!
(steeringTarget method)
https://arongranberg.com/astar/documentation/dev_4_1_0_9f8b6eb7/class_pathfinding_1_1_rich_a_i.php#a399e2bebfc8dfaf4fd291f051ca486e6

For questions related to A* Pathfinding Project it may be better to ask on the developer forum.
But here's my experience using it.
Usually you start with a seeker.
public Seeker seeker;
Since pathfinding calculations are asynchronous you must register for an event that tells us when the path is ready.
seeker.pathCallback += OnPathComplete;
Somewhere in your code you call to search for a path.
seeker.StartPath(start, end);
When the path is ready you will get a Path object. It contains all of the points and vectors.
List<GraphNode> path;
List<Vector3> vectorPath;
You can use the built-in PathInterpolator to smooth out the movement.
When you get the new path pass the vector path to the interpolator.
interpolator.SetPath(path.vectorPath);
On FixedUpdate you need to interpolate and apply the movement.
interpolator.MoveToCircleIntersection2D(transform.position, 0.1f, GraphTransform.identityTransform);
var moveDir = (interpolator.position - this.transform.position).normalized;
// Apply moveDir to Rigidbody, or whatever.

So thanks to the guy that tried to help, but that was not it. I solved my problem this way.
Vector2 direction = ((Vector2)path.vectorPath[currentWaypoint] - rb.position).normalized;
So this is the vector that's needed. From this game object to the end of the waypoint. Your code may vary.
Vector2 force = direction * speed * Time.deltaTime;
And this is the variable that is needed. So we set the animator with force.x and force.y and this should work.
I hope I made this at least somewhat clear. But if not - ask away.

Jumping increases movement speed

I'm making a game with ball physics and an FPS camera. I have this bug where the player's movement is increased when I jump.
Example:
Running along the Z axis on a plane:
Suddenly jumping:
My code:
void Update()
{
// Input
moveFwrd = Input.GetAxis("Horizontal");
moveSide = Input.GetAxis("Vertical");
// Player Jump
if (Input.GetKeyDown(jumpKey) && Physics.Raycast(
transform.position,
Vector3.down,
DistanceToTheGround + 0.1f))
{
rb.AddForce(Vector3.up * jumpSpeed, ForceMode.Impulse);
}
// Braking
if (Input.GetKey(brakeKey))
{
rb.angularDrag = brakeForce;
}
else
{
rb.angularDrag = 0.01f;
}
}
void FixedUpdate()
{
// Player Movement
Vector3 movement = cam.transform.right * moveFwrd +
cam.transform.forward * moveSide;
movement = movement.normalized;
rb.AddForce(movement * speed);
}
}

Most likely, the answer is friction. Depending on the physics material used for the player's Rigidbody collider and the physics material used for the floor, the Rigidbody will behave differently:
Static friction describes the friction when both objects are not moving (i.e. before the player starts moving), dynamic/kinetic/sliding friction describes the friction when the player is moving along/on the floor. It will also determine if the rigidbody slides or rolls on the floor, you could experiment with different physics materials to see the effects.
The reason why you see faster movement in mid-air in forward direction after pressing the jump button is that the Rigidbody is no longer affected by "contact friction" between solid materials while airborne, hence it will move faster with the same applied forward force. - However, there's still friction involved: air resistance; which can be controlled by Rigidbody.drag and Rigidbody.angularDrag.
If you want to get rid of this simulated bahavior, you could do various things: Use different physics materials, Rigidbody.drag, Rigidbody.mass values, or try to experiment with a different ForceMode like ForceMode.VelocityChange arguments in Rigidbody.AddForce(). Or do not use the physics engine and rigidbodies at all for motion (colliders and raycasts can still be used).
Side notes:
FixedUpdate() is called at regular intervals, and is the recommended place to do physics related scripting. It is actually called at the same frequency as the internal physics engine is updated, like documented here. The duration between every call is constant: Time.fixedDeltaTime.
Update() on the other hand is called at a variable rate, and has a variable duration Time.deltaTime, which results in different frame rates (FPS). This method can be used for the visual rendering or state processing of the game, and should not be used to update physics related stuff if possible.
In the script above, you use Rigidbody.AddForce() in both methods Update() and FixedUpdate(). In the latter with the default argument ForceMode.Force and in the other case with ForceMode.Impulse. In both cases you do not take the frame time into account, which is fine in the case of an impulse, applied once (after a key has been pressed). In the other case the direction vector gets normalized, so it isn't really a problem either, because the method is called at a fixed rate... but it could be written a bit more clearly.

Bouncing my player further the closer I am

I'm recreating the movement system from the DS game Dragon Quest Heroes Rocket Slime in Unity. Currently I've got pretty desirable results but it's not 100%.
One of the things that are different is that my player bounces back from walls further on long distance slings than he does in the original game. (left is my recreation, right is original game). Obviously, I can't find out how the game was made and the exact maths/values they use for slinging but one of the things I got from the game is that:
The player moves at constant velocity while slinging in a direction (no slow down, they just stop at a certain point)
Which led me to believe the game doesn't use traditional velocity mechanics so I made it so:
While stretching, the players 'pVelocity' (potentialVelocity) goes up. When they let go a point create at curPlayerPosition + pVelocity is created. I then move the player at a constant velocity to that point. My idea to fix my issue of bouncing too far is by getting the distance from the position where I slung from to the end point and making the player bounce less the larger the distance and further the smaller the distance.
Problem is, I'm not really sure how to do that last part.
Here's my code:
Vector2 reflectedVelocity = Vector2.Reflect(pVelNormalized, foundHit.normal);
playerAnimator.SetFloat("VelocityX", reflectedVelocity.x);
playerAnimator.SetFloat("VelocityY", reflectedVelocity.y);
float DistanceFromOrigin = Vector3.Distance(slingOrigin, transform.position);
print(DistanceFromOrigin);
//ToDo: reflectedVelocity is lower the higher DistanceFromOrigin is.
The other solution I thought of is that maybe my idea of how the 'velocity' works in the original game is completely wrong and if so, please tell me how it actually is/looks to be actually done

reflectedVelocity is lower the higher DistanceFromOrigin is.
So reflectedVelocity should have an inverse relationship with DistanceFromOrigin
Vector2 reflectedVelocity = Vector2.Reflect(pVelNormalized, foundHit.normal);
float DistanceFromOrigin = Vector3.Distance(slingOrigin, transform.position);
if(DistanceFromOrigin == 0) DistanceFromOrigin = 0.00001f;//to avoid division by zero
reflectedVelocity *= (SomeConstant / DistanceFromOrigin);
playerAnimator.SetFloat("VelocityX", reflectedVelocity.x);
playerAnimator.SetFloat("VelocityY", reflectedVelocity.y);
You may use a linear relationship instead of non-linear:
reflectedVelocity *= (SomeConstant - DistanceFromOrigin);

Unity Ball Shaking as it moves

I have a ball game object that I am making bounce using explicit physics equations. I tried using unity's physics engine, but It was not exact enough. I am setting the balls position like so:
float dTime = Time.time - timeSinceBounce;
ballPosition.x -= meterOffset / sensitivity;
ballPosition.y = ballInitialPosition.y + GameConstants.Instance.GetBallYVel ()
* dTime - (float)0.5 * GameConstants.Instance.GetGravity () * dTime * dTime; //Yi+Vy*t-0.5(G)(time^2)
ballPosition.z = (-dTime * GameConstants.Instance.GetBallZVel ()
+ ballInitialPosition.z) * startConstant; //Zi + t*Vz
ball.transform.position = ballPosition;
This code runs in the Update() method. When a collision is detected the time and initial position as reset, and this works. Currently the ball bounces properly but shakes when it is moving quickly. The FPS is at 80. I don't think my equations are wrong because it bounces properly there is just a shake. What is the best way to remove the shake? Thank!
Edit 1: I decided to write my own physics because Unity's physics engine had a lot of other components like friction and roll that were making the ball's bounces vary. Also the camera's x and y is fixed the only thing that is changing is the camera's z position. It works a lot better in fixed update

As of asker's request I hereby add all the details I can, even though without seeing the actual, full and complete code along with seeing this "shake" effect it's challenging to give an exact and proper answer. I'll try and do my best though.So let's do this.
1. "Shaking" reason: most probably you set up some kind of animation, along with a forced positioning/rotation/etc and these two codes work against each other. Double-check your AnimatorController and Animator as well as your Mecanim if you have set/configure these (also a good read: "Locomotion").You can also keep the Animator Window open while you are testing from Unity UI, to see who is the tricky guy doing the "shaking" effect for you, and get one step closer to why it happens.If these don't help, start from scratch: Minimize the code you wrote to move the ball, remove every effect, etc and add them back one by one. Sooner or later "shakieness" will come back (if it persist with the cleanest possible code, see above, Animator/Locomotion issue)
2. Think again not rewriting Unity Physics... You mention for example "...physics engine had a lot of other components like friction and roll that were making the ball's bounces vary...".Now, this is something you can turn off. Completely if you want. Easiest way is to set everything to zero on Physics Material (i.e. friction and bouncieness) but if you want Unity to ignore all and every "actual physics" and let you do what you want with your GameObject, tick in the isKinematic property of the Rigidbody. The fun part of it, you'll still collide if and where you want, can AddForce, etc yet neither gravity nor friction or "anything physical" affect you.If you are not comfy with Unity (and you are not it seems), I highly recommend learning about it a bit first as it is a very good and very powerful engine - so don't throw it's features away as they don't work as you initially expected they'll do. For example, Sebastian Lague just started a great beginner series a few weeks ago. The guy is a teacher, his videos are both short, fun and full of information so I can just recommend his channel.
3. As of your code I would make these changes:
public static class GameConstants { //no monobehaviour == can be a "proper, global" singleton!
public static float GetGravity {
get { return [whatever you want]; }
//why not Physics.gravity, using locally when and where it's needed?
}
//etc, add your methods, properties and such
//use this approach if and only IF you access these values application wide!
//otherwise, instead of a """singleton""" logic you just implemented,
//consider adding an empty GameObject to the Scene, name it "GM" and
//attach a "GameManager" script to it, having all the methods and
//properties you'll need Scene-wide! You can also consider
//using PlayerPrefs (see help link below) instead of a global static
//class, so you save memory (but will need to "reach out" for the data)
}
private void FixedUpdate() { //FIXED update as you'll work with physics!
//float dTime = Time.time - timeSinceBounce; //not needed
//positioning like this is not recommended, use AddForce or set direction and velocity instead
ballPosition.x -= meterOffset / sensitivity;
ballPosition.y = ballInitialPosition.y + GameConstants.Instance.GetBallYVel ()
* Time.fixedDeltaTime - 0.5f * GameConstants.Instance.GetGravity () * Time.fixedDeltaTime * Time.fixedDeltaTime; //Yi+Vy*t-0.5(G)(time^2)
ballPosition.z = (-dTime * GameConstants.Instance.GetBallZVel ()
+ ballInitialPosition.z) * startConstant; //Zi + t*Vz
ball.transform.position = ballPosition;
}BUT to be honest,
I would just throw that code away, implement the Bouncing Ball example Unity Tutorials offer, alter it (see point #2) and work my way up from there.
Items not linked but I mentioned in code:
PlayerPrefs, Physics.gravity and Rigidbody.velocity.
Note that 'velocity' is ignoring parts of physics (speeding up, being "dragged", etc) i.e. objects suddenly start moving with the speed you set (This is why Unity5 recommends AddForce instead -linked above-)
It might also come handy you can alter the FixedUpdate() frequency via Time Management, but I'm not sure this is yet needed (i.e. just for bouncing a ball)
I hope this helps and that ball is going to bounce and jump and dance and everything you want it to do ;)
Cheers!

Constant speed for Adding Force without affecting jump

There seem to be a fair amount of questions similar to this but none seem to really answer. I have a gameobject that can jump on a click of a button and automatically keeps going right.
I need the right moving motion to be constant but it ends up building faster and faster over time. If I use Velocity instead of AddForce, the motion is constant. But when I mouse click to jump, it takes like 10 over seconds to reach back down to ground.
Can I please get assistance on how I can keep the automatic movement to the right constant and still able to jump and reach back to ground fast. The following is my code. Thank you.
Edit:
Desired result
Gameobject constantly moving same speed to the right. When I jump, gameobject jumps and comes back down to ground over a period of 0.5 secs.
Jump is expected to be like a smooth flow like a ball that jumps and comes back down smoothly.
Current result Using AddForce to move right
Gameobject starts to move right slowly and picks up speed over time getting faster and faster thus not able to keep constant same speed.
Current result Using Velocity to move right
Gameobject able to keep constant speed as wanted, but when I jump the Gameobject jumps and takes about 10 seconds to get back down to ground (It slowly glides back down).
public float jumpSpeed = 300;
public float maxSpeed = 15;
Rigidbody rb;
void Start()
{
rb = GetComponent<Rigidbody>();
rb.velocity = Vector2.ClampMagnitude(rb.velocity, maxSpeed);
}
void Update()
{
if (Input.GetMouseButtonDown(0))
{
rb.AddForce(Vector3.up * jumpSpeed);
}
}
void FixedUpdate()
{
rb.AddForce(Vector3.right * maxSpeed);
}
//Trying to change velocity instead - Able to keep constant speed but when I jump, takes about 10 secs to get back down to ground.
public float jumpSpeed = 2000;
public float maxSpeed = 5;
Rigidbody rb;
void Start()
{
rb = GetComponent<Rigidbody>();
rb.velocity = Vector2.ClampMagnitude(rb.velocity, maxSpeed);
}
void Update()
{
if (Input.GetMouseButtonDown(0))
{
rb.AddForce(Vector3.up * jumpSpeed);
}
}
void FixedUpdate()
{
rb.velocity = new Vector2(5, 0);
}

I think there are a few points of confusion here, so I'll answer some clarifying questions of my own.
Why does the speed of the object increase without bound when using add force?
The AddForce command will increase the velocity of the object every time you apply it. In the code, this means every call to FixedUpdate is increasing the velocity.
I think the misunderstanding is related to this line of code in your Start method:
rb.velocity = Vector2.ClampMagnitude(rb.velocity, maxSpeed);
Vector2.ClampMagnitude is not persistent. That is to say, it does not clamp the magnitude going forward. What you probably meant was to prevent the velocity from ever breaking "maxSpeed" in which case you should call the clamp method in FixedUpdate.
However, this would have a different effect which you might not intend. When the game object is moving along only one axis, the entire magnitude of the velocity is along that axis. Once the game object begins moving along a second axis, for instance while jumping, the magnitude of the velocity is split across both. This means that while your game object is jumping (has a y component to its velocity) its horizontal speed (the x component of its velocity) would be diminished. In other words, jumping would slow down your game object's movement to the right.
Why does my object "float" slowly downwards when setting the velocity directly?
One of the advantages of using AddForce is that it modifies the targeted axis of a vector without modifying the others. Setting the velocity directly is a little more tricky because you may accidentally clobber the velocity changes caused by physics.
For instance, in your FixedUpdate code:
rb.velocity = new Vector2(5, 0);
is setting the x velocity of your object to 5 - creating the smooth horizontal movement you want - but at the same time, setting the y velocity to 0.
This is why you needed to crank your jumpSpeed up to 2000 to see any effect on the object's height: it only has a split second to move upwards before the FixedUpdate method resets its upward motion to 0. This is also why your object appears to be "floating" back to earth. The internal physics engine is trying to apply gravity to the object but is being foiled by your code which constantly resets the objects downward velocity.
One Other Comment
I noticed you had some code in your Update method that was acting on the object's physics - that is your jump code. A good rule of thumb is to keep all the code working on an object's physics in the FixedUpdate method, since this is called just before the physics engine does it's work while the Update method is called just before the rendering engine does its work to draw the game.
One Possible Solution
The AddForce technique is normally recommended when working on an object's velocity because it creates natural looking physics through acceleration. Setting an objects velocity directly can create strange looking effects because objects in reality don't work this way. For instance, imagine what it would look like to see a car change from 0mph to 60mph in less than a split second.
If you check Unity's documentation on Rigidbody.velocity, you'll see they make this same recommendation, but add that jumping may be a scenario where you want to break this rule. However, as I mentioned earlier, we need to be careful when setting the y velocity explicitly so as to avoid changing the object's speed along other axes.
public float jumpSpeed = 2;
public float maxSpeed = 1;
Rigidbody rb;
void Start()
{
rb = GetComponent<Rigidbody>();
}
void FixedUpdate()
{
var newVelocity = rb.velocity;
if (Input.GetMouseButtonDown (0))
newVelocity.y = jumpSpeed;
newVelocity.x = maxSpeed;
rb.velocity = newVelocity;
}