I'm a bit confused about some documentation for Unity pertaining to Euler angles. I just want to know if I'm not understanding a difference, or the sample does not follow the best practice. The documentation here
states:
Only use this variable to read and set the angles to absolute values. Don't increment them, as it will fail when the angle exceeds 360 degrees. Use Transform.Rotate instead.
Meanwhile, the code sample appears to be using increments that could exceed 360 degrees:
using UnityEngine;
using System.Collections;
public class ExampleClass : MonoBehaviour {
public float yRotation = 5.0F;
void Update() {
yRotation += Input.GetAxis("Horizontal");
transform.eulerAngles = new Vector3(10, yRotation, 0);
}
void Example() {
print(transform.eulerAngles.x);
print(transform.eulerAngles.y);
print(transform.eulerAngles.z);
}
}
Wouldn't incrementing a variable and then using that variable to set the value absolutely still run the risk of exceeding 360 degrees if the variable is over 360 degrees?
When you rotate your Object using euler angles then when it reaches 360 and try to exceed further, it becomes (minus)-360 and gradually increase from -359 to -1.
After executing following code your values will not exceed from 360 and will remain positive.
float rotateAngle = rotateObject.transform.localEulerAngles.y;
// Convert negative angle to positive angle
rotateAngle = (rotateAngle > 180) ? rotateAngle - 360 : rotateAngle;
rotateObject.transform.localEulerAngles = new Vector3(rotateObject.transform.localEulerAngles.x, rotateAngle, rotateObject.transform.localEulerAngles.z);
There are differences. When doing:
transform.eulerAngles.y += 1F;
You are invoking the += operator in Vector3.
However, when you set eulerAngles this way:
float newY = transform.eulerAngles.y + 1F;
transform.eulerAngles = new Vector3(.., newY, ..);
You are invoking a setter in Transform, and inside this setter, it probably includes the action of updating Transform.rotation.
The difference is that Unity can implement the updating logic in Transform class instead of the Vector3 class, which makes much more sense there.
We can verify this further below in the documentation:
Do not set one of the eulerAngles axis separately (eg. eulerAngles.x =
10; ) since this will lead to drift and undesired rotations. When
setting them to a new value set them all at once as shown above. Unity
will convert the angles to and from the rotation stored in
Transform.rotation.
Related
How can I keep the diagonal speed to be the same as the horizontal and vertical speed without clamping any value or using ".normaized". I tryed to normalize the values but I lost the joystick values between 1 and 0. Here is my code :
void ListenInput()
{
Vector3 rightDirection = camera.right;
Vector3 frontDirection = camera.GetForwardFromAngleY();
move = new Vector2(
Input.GetAxis("Horizontal"),
Input.GetAxis("Vertical")
);
MoveCharacter(rightDirection * move.x);
MoveCharacter(frontDirection * move.y);
}
void MoveCharacter(Vector3 velocity)
{
transform.position += velocity * Time.deltaTime * runningSpeed;
}
Here, you should clamp the magnitude of the input Vector2.
For example with Vector2.ClampMagnitude() from the Unity API.
That will keep the input non-binary and prevent the diagonal from getting larger than purely horizontal/vertical inputs.
void ListenInput()
{
Vector3 rightDirection = camera.right;
Vector3 frontDirection = camera.GetForwardFromAngleY();
move = new Vector2(
Input.GetAxis("Horizontal"),
Input.GetAxis("Vertical")
);
move = Vector2.ClampMagnitude(move, 1f);
MoveCharacter(rightDirection * move.x);
MoveCharacter(frontDirection * move.y);
}
void MoveCharacter(Vector3 velocity)
{
transform.position += velocity * Time.deltaTime * runningSpeed;
}
If you normalize a vector you will make sure it's length is 1. This is a great way to avoid quirks like "diagonal movement is faster than normal movement".
However, the fact that the length is always 1 also means that there is no "move slowly" or "move at full speed" distinction from the joystick. When you say "I lost the joystick values between 1 and 0" is due to this fact.
One way developers get around this is by using a mathematical formula to scale the speed.
You could:
Use the largest value (horizontal or vertical) to control the speed
Use the smallest value
Use a combination of the two
Another way to do this is to store how long ago the movement started, then scale the speed based on that. This method has its own challenges, but is very familiar to players.
Examples
For instance, if I have:
horizontalInput = 1
verticalInput = 0.5
This means my normalized vector looks like this:
I could:
Use the largest value
Move at full speed (1) on the direction of my vector.
Use the smallest value
Move at half speed (0.5) on the direction of my vector.
Use a Use a combination of the two values
For this instance, lets use the following formula: (x+y)/2.
Move at 3/4 speed (0.75) on the direction of my vector.
NOTE: This formula will not "feel" as nice if you have x=0 and y=1, this is just an example. You most likely want to use Min, Max, Avg and if-clauses to control how the speed works.
You can use different formulas and different techniques to make the movement in your game feel like what you want, but take the time to analyze WHY it feels like that.
I need to display the rotation in Euler angles of an object's certain axis.
I am aware that retrieving the rotation of an object in Euler angles gives inconsistent results, some of which can be solved by simply using modulo 360 on the result. however one permutation that unity sometimes does when assigning a vector with the value of "transform.localRotation.eulerAngles" is instead of retrieving the Vector3 "V", it retrieves "(180, 180, 180) - V".
to my understanding, "(180, 180, 180) - V" does not result in the same real world rotation as V, unlike "(180, 180, 180) + V" which does leave the actual rotation unaffected.
what is the explanation for the phenomenon, and what is the best way of normalizing an Euler angles rotation vector assuming I know the desired and feasible value of one of its axes? (for example, to normalize it such that all of it's values are mod 360 and it's Z axis equals 0 assuming it does have a representation in which Z = 0)
I don't know about the first part of the question (it is different enough to be its own question imo) but I can answer your second one.
So, you have these inputs :
Quaternion desiredRotation;
float knownZ;
And you're trying to find Vector3 eulers where eulers.z is approximately knownZ and Quaternion.Euler(eulers) == desiredRotation.
Here's the procedure I would use:
First, determine the up direction rotated by desiredRotation and the up and right direction rotated by a roll of knownZ:
Vector3 upDirEnd = desiredRotation * Vector3.up;
Quaternion rollRotation = Quaternion.Euler(0,0,knownZ);
Vector3 upDirAfterRoll = rollRotation * Vector3.up;
Vector3 rightDirAfterRoll = rollRotation * Vector3.right;
We know the local up direction after desiredRotation is applied and that the only thing that can adjust the up direction after the roll knownZ is applied is the rotation done by the euler pitch component. So, if we can calculate the angle from upDirAfterRoll to upDirEnd as measured around the rightDirAfterRoll axis...
float determinedX = Vector3.SignedAngle(upDirAfterRoll, upDirEnd, rightDirAfterRoll);
// Normalizing determinedX
determinedX = (determinedX + 360f) % 360f;
...we can determine the x component of eulers!
Then, we do the same with the yaw component of eulers to make the new forward direction line up with the end forward direction:
Vector3 forwardDirEnd = desiredRotation * Vector3.forward;
Quaternion rollAndPitchRotation = Quaternion.Euler(determinedX, 0, knownZ);
Vector3 forwardDirAfterRollAndPitch = rollAndPitchRotation * Vector3.forward;
Vector3 upDirAfterRollAndPitch = upDirEnd; // unnecessary but here for clarity
float determinedY = Vector3.SignedAngle(forwardDirAfterRollAndPitch, forwardDirEnd, upDirAfterRollAndPitch );
// Normalizing determinedY
determinedY = (determinedY + 360f) % 360f;
Vector3 eulers = new Vector3(determinedX, determinedY, knownZ);
To ensure that the given quaternion can be made with the given component, you could check if the axes given to SignedAngle actually can rotate the input vector to the target vector, or you can just compare the calculated eulers and the given quaternion:
Quaternion fromEuler = Quaternion.Euler(eulerAngles);
if (fromEuler==desiredRotation)
{
// use eulerAngles here
}
else
{
// component and quaternion incompatible
}
Hopefully that helps.
I'm not quite sure I understand your question correctly, but the euler angles just represent the angles of 3 rotations applied around the 3 axis in a specific order, right? So why would you normalize it by adding 180 everywhere? You should bring each angle individually into the range 0-360 by modulo-ing them.
Your question seems to imply that you can obtain any orientation by only rotating around two axis instead of three... is that what you are trying to achieve?
Using quaternions could possibly help you, in fact an orientation can be defined with just 4 scalar values: an axis and an angle
Hi I am using this code to have objects moving on the y axis.
using UnityEngine;
using System.Collections;
public class TargetMovementVertical : MonoBehaviour
{
public int maxSpeed;
private Vector3 startPosition;
// Use this for initialization
void Start ()
{
startPosition = transform.position;
}
// Update is called once per frame
void Update ()
{
MoveVertical ();
}
void MoveVertical()
{
transform.position = new Vector3(transform.position.x, Mathf.Sin(Time.time * maxSpeed), transform.position.z);
if(transform.position.y > 1.0f)
{
transform.position = new Vector3(transform.position.x, transform.position.y, transform.position.z);
}
else if(transform.position.y < -1.0f)
{
transform.position = new Vector3(transform.position.x, transform.position.y, transform.position.z);
}
}
}
My only problem is that the object are only moving within 1 and -1 and i would like to have them move lower. is there a possible way please ?
Programming
In your code, you are setting the position using this line:
transform.position = new Vector3(transform.position.x, Mathf.Sin(Time.time * maxSpeed), transform.position.z);
Here, the only coordinate that is changing is the y coordinate. And it changes according to the function Mathf.Sin.
If you read the documentation for Mathf.Sin you will find that it returns values between -1 and +1.
That is why...
the object are only moving within 1 and -1
The simple solution is to multiply the result of Mathf.Sin by some factor.
Math
This is the sine function:
red plot: y = sin(x)
As you can see, the range of the sine function is [-1, 1]. Thus, regardless of what input value you put into the function, you will get a result in the interval [-1, 1].
If you multiply the input, you are changing the frequency of the sine wave, for example:
Red plot: y = sin(5x)
Observe that placing a factor inside the function will not affect the amplitud of the wave. Compare with the following:
Red plot: y = 5sin(x)
The above graph, at difference with the prior ones, has the range [-5, 5].
Here you can see them all for comparison:
Red plot: 5sin(x)
Blue plot: sin(x)
Purple plot: sin(5x)
These plots were created with the graphing calculator from meta-calculator. You can try the functions there yourself if you don't want to take my word for it.
To understand why the sin function has this shape, remember that the sine function takes an angle and returns the vertical component of a unit vector that has angle with the horizontal...
I mean this:
Unit circle with sine and cosine, θ=45 degrees.
Since we are taking a unit vector, (we are working on the unit circle), the maximum value that the vertical (sine) will take is 1, and the minimum is -1.
To understand how the sine plots we saw above come from this, I hope this animation makes it clearer:
Animation showing how the sine function (in red) y = sin(θ) is graphed from the y-coordinate (red dot) of a point on the unit circle (in green) at an angle of θ in radians.
Back to programming
As I said at the start of the answer, if you want to scale the movement, you can change the amplitude to the sine wave by multipliying the result by some factor, for example: Mathf.Sin(angle) * amplitude.
That amplitude value will tell how far the value will reach, that is, by multiplying by Mathf.Sin by amplitude you get a value in the range - amplitude and + amplitude.
I expect that you find that approach reasonable know that the reasoning behind it have been presented.
I hope the above explanation makes it clear that the sine function does not preserve factors. That is: sin(a*x) ≠ a*sin(x). In other words that the sine function is not transitive with scaling, the reason for that is that the sine function is NOT a linear transformation.
im trying to move a object in unity between 2 points, and at the moment it kinda works strange, i read the documentation and it says that the object begin point is (0,0,0) so my object goes under my other mesh that i have there, and the end point i can actually control, in my case it is 10, i want the object to move between 1.5 and 10(not 0 to 10)
i have this
void Update () {
transform.position = new Vector3(transform.position.x,Mathf.PingPong(Time.time,10.0f), transform.position.z);
}
when i try to put speed on the ball doing this:
void Update () {
transform.position = new Vector3(transform.position.x,Mathf.PingPong(Time.time,10.0f) * 10, transform.position.z);
}
the object does not colide and goes back at the end point it just stop looping and never came back how can i correct this 2 problems?
If your object has a collider, I suggest you move it via its Rigidbody rather than its Transform, to avoid potential collision issues. Try this:
public float MinY = 1.5f; // y position of start point
public float MaxY = 10f; // y position of end point
public float PingPongTime = 1f; // how much time to wait before reverse
public Rigidbody rb; // reference to the rigidbody
void Update()
{
//get a value between 0 and 1
float normalizedTime = Mathf.PingPong(Time.time, PingPongTime) / PingPongTime;
//then multiply it by the delta between start and end point, and add start point to the result
float yPosition = normalizedTime * (MaxY - MinY) + MinY;
//finally update position using rigidbody
rb.MovePosition(new Vector3(rb.position.x, yPosition, rb.position.z));
}
Here you have a better control on the distance to travel, and the speed.
Actually I didn't get exactly what are the problem you faced. But don't forget here and in your try, that you are directly modifying the position of the object, not adding forces or else.
Hope that helps you.
I think you simply misunderstood how the Mathf.PingPong method works :
first argument t is the value you want to "clamp" between 0 and the given length : this is were you want to put the Time.time as you did since this value will increase over time and therefore perpetually oscillate. If you want to increase/decrease the oscillation speed you have to multiply it.
second argument length is the max value of the "clamp" : if you want to increase/decrease the distance (in your case) you have either set it to 0 and multiply the whole Mathf.PingPong(...) by a value or directly give it the wanted value (both implementations will have a different effect.
Mathf.PingPong(Time.time * speed, 1.0f) * value : speed will affect the oscillation speed / value will affect the max value reached AND the speed / time to complete the oscillation (back and forth) will remain the same as value changes and decrease as speed increases
Mathf.PingPong(Time.time * speed, value) : speed will affect the oscillation speed / value will affect the max value reached BUT NOT the speed / time to complete the oscillation (back and forth) will increase as value increases and decrease as speed increases
About your other problems :
If you want to move your object between 1.5 and 10 you have to write something like this :
transform.position = new Vector3(transform.position.x, 1.5f + Mathf.PingPong(Time.time, 10.0f - 1.5f), transform.position.z);.
Also if you want to detect collision, avoid setting position manually as it will mess up with Physics and cause weird behaviors. Best way to move your object while keeping physic working is to do as #Heldap said using Rigidbody.MovePosition.
I have some problems with a rotating marble.
I've tried it with Matrix.CreateFromYawPitchRoll and Matrix.CreateRotation but there were some problems, I think it's due to the Gimbal lock effect.
So, I've tried using quaternions instead, but nothing changed.
When moving on only an axis it works fine, but when the rotation occurs on two different axes the marble still rotates on wrong axes.
Here's my code:
// declarations
Vector3 Position = Vector3.Zero;
Vector3 Rotation = Vector3.Zero;
Quaternion qRotation = Quaternion.Identity;
AbsoluteBoneTransforms = new Matrix[Model.Bones.Count];
Model.CopyAbsoluteBoneTransformsTo(AbsoluteBoneTransforms);
In the Update method:
Position += speed;
Rotation = speed * MathHelper.ToRadians(-1.5f);
Quaternion rot = Quaternion.CreateFromAxisAngle(Vector3.Right, Rotation.Z) *
Quaternion.CreateFromAxisAngle(Vector3.Backward, Rotation.X);
qRotation *= rot;
And in the Draw method:
effect.World = AbsoluteBoneTransforms[mesh.ParentBone.Index] *
Matrix.CreateFromQuaternion(qRotation) * Matrix.CreateTranslation(Position);
What's wrong? Is it wrong to use Quaternion.CreateFromAxisAngle on multiple axes?
EDIT
I've tried calculating directly the axis of rotation of my marble, instead of using combination of multiple axes:
angle += speed.Length() * angularVelocity;
qRotation = Quaternion.CreateFromAxisAngle(Vector3.Cross(speed, Vector3.Up), angle);
qRotation.Normalize();
angle is a float that keeps track of the current movement.
This solution doesn't seem to create Gimbal lock, but marble rotations aren't correct, it seems that the rotating speed is not constant, but became faster and slower over time, I can't understand why.
If I "concatenate" the quaternions I get every frame using
qRotation *= Quaternion.CreateFromAxisAngle(Vector3.Cross(speed, Vector3.Up), angle)
the Gimbal lock effect is still visible.
Here's how I've tackled that:
I'm assuming speed is a vector representing the direction the ball is rolling and whose magnitude represents the rate it is traveling in that direction.
Vector3 axis = Vector3.Cross(speed, Vector3.Up);
float angle = speed.Length();//factor by delta time if neccesary
Quaternion rotationThisFrame = Quaternion.CreateFromAxisAngle(axis, angle * (1/radiusOfBall));
then you can concatenate that to your qRotation. Also, you may need to normalize your quaternion after concatenation.
Update: The correct answer to this question/thread was reversing the order that quaternions concatenate in. With respect to XNA, matrices combine left to right, quaternions combine right to left.