When something hits the Player, maybe an enemy or spikes etc., I want him to get knocked back in the oppisite direction of the enemy.
So what I already got:
public void ChangeHealth(float healthToAdd, Vector2 objectPosition) // Change the players health, objectPosition = enemies position or something else
{
if (healthToAdd < 0) // incoming damage
{
// ... other stuff
Knockback(objectPosition);
}
// ... other stuff
}
void Knockback(Vector2 objectPosition) // Knockback routine
{
Vector2 knockbackPosition = new Vector2( , ); // calculation is missing here! Calculate the new position by the knockback direction
rigid.MovePosition(Vector2.MoveTowards(playerPos, knockbackPosition, 2 * Time.deltaTime)); // the knock back
}
private void Update() // !! TEST !!
{
if (Input.GetKeyDown(KeyCode.E)) // TEST routine
{
ChangeHealth(-7, new Vector2(10,10)); // decrease players health by 7 and knock him back
}
}
And what is missing:
Vector2 knockbackPosition = new Vector2( , );
I am looking for a calculation like this picture is showing:
Vector2 knockbackPosition =
transform.position + (transform.position - objectPosition).normalized *a
To understand why is it equal to that you have to read through.
There are three points: E,P,K (Enemy, Player, Knockback)
And one scalar number: a (the greater this value is, the more knockback you'll have)
Now from your picture:
PK = EP*a
expand vectors into distances between two points:
(K-P) = (P-E)*a
calculate the location of K:
K = P + (P-E)*a
There is one problem though. (thanks to Rotem) with this formula as it is:
you'd expect a bigger knockback from a closer opponent.
We don't want the knockback to be dependent on the distance between P and E.
To remove the dependency on the former, normalize the vector before multiplying by a
So we add .normalized to use just the direction of (P-E) instead of its original vector
Related
So i have a small code in my 2d game in unity that if my enemy's y position equal to my player's y position, then my Enemy will shoot a bullet, the thing is right now my enemy need exactly position to take a shoot, so is there anyway that i can add and offset to get this easier
if (target.position.y == boss.position.y)
{
Shoot();
}
You can simply find the distance between two values by doing |x - y|
var targetPosition = target.position.y;
var enemyPosition = boss.position.y;
var offSet = 3f;
var shouldShoot = Mathf.Abs(targetPosition - enemyPosition) <= offSet;
if(shouldShoot) {
Shoot();
}
My problem is pretty simple, but yet I struggle to find an answer. Brief context, I have a sprite that moves accross the Y-axis according to microphone input. Beforehand, I prompted the user to record their lowest and highest note, calculated the frequency of these two notes and am using it as a reference for positioning the sprite on the Y-axis.
Let's say the lowest note is 100 Hz and the highest one 400 Hz. So if the player makes a tone of 100 Hz, the sprite should move down to the bottom of the Y-axis. To move back to the center (Y-position 0), the player would have to make a tone of 250 Hz (midpoint between 100 and 400).
So we know that for that player, 250 Hz equals to Y-position 0. But I need to know the Y-position equivalents of the lowest note (bottom edge) and highest note (top edge). When I move the sprite manually to the top edge and look at the Y-value in the inspector, it's apparently 4.58. But I'm not sure if hard-coding 4.58 would scale well across different screen-sized devices.
Screenshot here: https://i.ibb.co/pjrkSNV/Capture.png
I ideally want to have a method called FrequencyToY(float frequency) that converts a frequency value to the corresponding Y-value on the axis. I saved the lowest and highest frequency values in PlayerPrefs. Important note about the sprite movement, I don't want gravity. The bird should just smoothly move to the corresponding Y-position every time the player produces a tone, and stay in place otherwise.
This is my current script attached to my sprite:
public class Player : MonoBehaviour
{
public AudioSource audioPlayer;
public AudioMixer masterMixer;
private float[] _spectrum;
private float _fSample;
private Transform playerTransform;
void Start()
{
playerTransform = transform;
//Code for microphone loop
masterMixer.SetFloat("masterVolume", -80f);
_spectrum = new float[AudioAnalyzer.QSamples];
_fSample = AudioSettings.outputSampleRate;
audioPlayer.clip = Microphone.Start("", true, 10, 44100);
audioPlayer.loop = true;
while(!(Microphone.GetPosition("") > 0)) { }
audioPlayer.Play();
}
void Update()
{
//Calculate frequency of currently detected tones
audioPlayer.GetSpectrumData(_spectrum, 0, FFTWindow.BlackmanHarris);
float pitchVal = AudioAnalyzer.calculateFrequency(ref _spectrum, _fSample);
if(pitchVal != 0)
{
if (pitchVal < PlayerPrefs.GetFloat("lowestFrequency"))
pitchVal = PlayerPrefs.GetFloat("lowestFrequency");
else if (pitchVal < PlayerPrefs.GetFloat("highestFrequency"))
pitchVal = PlayerPrefs.GetFloat("highestFrequency");
//This is how I'd like to call the function
//But if someone could change this and make the sprite actually
//"move" to that point instead of just popping there it would be awesome!
transform.position = new Vector2(0, FrequencyToY(pitchVal));
}
}
//Converts frequency to position on Y-axis
public float FrequencyToY(float frequency)
{
float x = 0;
return x;
}
}
You need to define the range of your Y coordinates that you want to use (say, 0 -> 100) and then scale the pitch you're given against their scale (so what % on 0 - 100 of their scale) and then use that % as a point on Y.
Thus, if they give you a note that's exactly in the middle of their scale (50%) and your Y coordinates in game range from 0-10, you want to put them at 5.
Consider two points: (0,0,0) as source and (1000,0,0) as target
A cube game object wants to travel from source and target at a pre-defined/constant speed. Time taken: t1
Introduce 100 intermediate points between source and target, i.e. INTERMEDIATE_POINTS = 10
Example: (0,0,0), (10,0,0), (20,0,0), (30,0,0).... (980,0,0), (990,0,0), (1000,0,0). Same speed, time taken: t2.
Introduce 50 intermediate points, i.e. INTERMEDIATE_POINTS = 20 ; (0,0,0), (20,0,0), (40,0,0),..., (960,0,0), (980,0,0), (1000,0,0). Same speed, time taken: t3.
Result: t1 < t3 < t2, i.e. more intermediate points, more time taken to reach the target (although same path and same speed)
Question: If you compare, the game object moves in the same way (same path, same speed) in all the three cases (no intermediates, 100 intermediates, and 50 intermediates) that are mentioned above. But why is there a time difference to reach the target?
Code to test this scenario:
using UnityEngine;
using System.Collections.Generic;
public class TestSpeed : MonoBehaviour
{
private List<Vector3> listOfPoints = new List<Vector3>();
private int INTERMEDIATE_POINTS = 1;
private int counter = 1;
private float speed = 50.0f;
private float originalDistance = 0.0f;
private float distanceCovered = 0.0f;
private float overshoot = 0.0f;
private Vector3 modifiedTarget;
// for the car movement.
private Vector3 targetPosition; // after every loop, get the next position
private Vector3 currentPosition;
// Use this for initialization
void Start()
{
for (int i = 0; i <= 1000; i = i + INTERMEDIATE_POINTS)
{
listOfPoints.Add(new Vector3(i, 0, 0));
}
currentPosition = this.transform.position; // at the beginning, from (0,0,0)
targetPosition = listOfPoints[counter];
}
// Update is called once per frame
void Update()
{
originalDistance = Vector3.Distance(targetPosition, currentPosition);
distanceCovered = Vector3.Distance(transform.position, currentPosition);
if(Vector3.Distance(transform.position, new Vector3(0,0,0)) >= 995.0f)
{
System.TimeSpan t = System.TimeSpan.FromSeconds(Time.timeSinceLevelLoad);
string answer = string.Format("{0:D2}:{1:D2}:{2:D2}",
t.Hours,
t.Minutes,
t.Seconds);
}
if ((originalDistance - distanceCovered) <= 0.0f)
{
currentPosition = transform.position;
targetPosition = listOfPoints[counter];
counter++;
}
else
{
float step = speed * Time.deltaTime;
if((distanceCovered + step) >= originalDistance)
{
overshoot = distanceCovered + step - originalDistance;
counter++;
modifiedTarget = Vector3.Lerp(targetPosition, listOfPoints[counter], (overshoot / originalDistance));
}
else
{
modifiedTarget = targetPosition;
}
transform.position = Vector3.MoveTowards(transform.position, modifiedTarget, step);
}
}
}
How to use the code:
Just create a cube game object and assign the script to it. Near to string answer set a break-point to check the time duration with various number of intermediate points.
I'm pretty sure this logic here is the cause of the strange observation:
if ((originalDistance - distanceCovered) == 0.0f)
{
currentPosition = transform.position;
targetPosition = listOfPoints[counter];
counter++;
}
You check whether or not you've arrived at your destination waypoint by checking for an exact position match; however, the distance you travel per Update is anything but exact. That means that your object could very well overshoot the destination, then try to move back towards it, overshoot it again, then repeat.
I bet if you watch your cube in the scene view, you'll see it hover around a single waypoint for a bit until it manages to hit the exact distance it needed.
You're probably better off using an inequality here, for example:
if ((originalDistance - distanceCovered) <= 0.0f)
{ /* ... */ }
Your object has reached its waypoint if the distance it has traveled is greater than or equal to the distance it needed to travel. originalDistance - distanceCovered will be negative as soon as the object has reached or passed the waypoint.
EDIT:
X.....X.....X.....X.....X.....X
Here are some waypoints. Pretend we have an object traveling along the path of waypoints. It starts at the first one on the left and goes right. It'll be represented by an O.
O.....X.....X.....X.....X.....X
Now it moves along for a while. Due to the variability of Time.deltaTime, it might move one or two spots each tick. So let's say it winds up here after a few ticks:
X....OX.....X.....X.....X.....X
And during the next tick, it moves two:
X.....XO....X.....X.....X.....X
With your original check, the object will now travel backwards. It needed to travel a distance of seven spaces, but it traveled 8. So with your original check, originalDistance - distanceCovered != 0.0f. So it'll keep trying to hit that spot over and over again until it hits it on the dot.
Even if you introduce the idea of a "threshold", you're still going to have the same problem. There is no fixed distance traveled per tick, so that means that each waypoint will have some artificial "bounce" time unless that threshold is so large that the waypoints become meaningless.
If you use originalDistance - distanceCovered <= 0.0f, you will always move on to the next waypoint if it overshoots. Instead of trying to land the object in some small window, you're just making sure that the object has passed or met its waypoint.
I'm working on an isometric game (diamond grid) and I've stumbled across a minor problem regarding a character movement.
I'm using A* to find a path between 2 points and then I want to move my character from point A to point B going through all the tiles which form the path but I can't find a way to do this , I mean a simpler and accurate method.
So far I've scrapped this piece of code but it's kinda "rusty"
public void Destination(tile destination)
{
for (int i = 0; i < 8; i++)
{
if (AdjacentTile[i] == destination)
{
characterDirection = i;
}
}
animation.changeSpriteDirection(characterDirection); //After I found which adjacent tile is the next destination I change the character direction based on it's position (1 = North , 2 = Nort Est etc) .. so the Y of the Animation_sourceRectangle it's changed//
Vector2 Position;
Position.X = current_characterTile.X - destination.X;
Position.Y = current_characterTile.Y - destination.Y;
rotation = (float)Math.Atan2(-Position.X, Position.Y);
moveVector = (Vector2.Transform(new Vector2(0, -1), Matrix.CreateRotationZ(rotation))) * characterSpeed;
movingCommand = 1; // the character is supposed to be moving..
Move(); //this function moves the sprite until the *tile.i and tile.j* of the character is the same as tile.j and tile.i of the destination
//something like this
if ( characterTile.i == destination.i && characterTile.j == destination.j)
movingCommand = 0 //stop
else
character_Position += moveVector;
}
If anyone could give me a hint on what to do or help me I'll be very grateful.
Thank You.
Possibilities:
At each tile, determine the character's speed vector and also determine how much time it will take for the character to move to next tile. When that time elapses, immediately begin moving to the next tile. (This is what I implemented below.)
At each tile, determine the character's speed vector. Then, when the character is sufficiently close to the next tile (say, the difference between their X and Y coordinates is less than 2 pixels?), snap it to the tile and begin moving to the next tile. This will causes artifacts and be in general less precise.
A solution:
Let's assume you already ran your pathfinding algorithm and found a linked list of a tiles that you must go through to arrive at target. Let's also assume those tiles cannot become blocked partway through the movement (it is simple to modify the algorithm if they can, though).
I usually do something like this to handle this problem:
Run the pathfinding algorithm, which returns a List, if a path
exists.
character.Path = theListThatAStarReturned;
character.beginMovingToTarget(character.Path[0]);
character.Path.RemoveAt(0);
The beginMovingToTarget() method will determine the velocity vector and also determine the the time needed to arrive at the tile. When the time is reached, we immediately go to the next tile, until the Path is empty. Let's call this time variable character.timeToArrival.
Update():
if (!character.Moving) return; // Or just don't execute the rest of this code.
character.position += character.speed * elapsedSeconds;
character.timeToArrival -= elapsedSeconds;
// Did the character arrive in a tile?
if (character.timeToArrival <= 0)
{
// This will ensure the character is precisely in the tile, not a few pixels veered off.
character.position = character.movingToTile.position;
if (character.Path.Count == 0)
{
character.Moving = false;
// We are at final destination.
}
else
{
character.beginMovingToTarget(character.Path[0]);
character.Path.RemoveAt(0);
}
}
And the beginMovingToTarget(targetTile) function:
this.movingToTile = targetTile;
Vector2 direction;
direction = targetTile.position - this.position;
this.timeToArrival = direction.Length() / this.speedPerSeconds;
direction.Normalize();
direction *= this.speedPerSeconds;
this.speed = direction;
// Here, you may also want to change the character's animation, if you want to, or you may do that directly in the Draw() method based on its speed vector.
Make sure the division is in floats, not integers.
I would like to understand how to measure the distance between two 3D objects, let's call them a parent object and a child object. Think of the parent as the body of a car and the child being a wheel of the car.
I understand how to get the difference based on the objects position in world space but I would like to get the difference as a measurement based on the parents relative object space.
E.g if the parent is facing East and the child is 2X, 3Y from the parent, measured in a relative sense. Such that if the parent rotated 60 degrees, the relative location of the child remains at a distance of 2x, 3y in the object space. Where as in a world space sense the child objects measurement as a Vector3 would be quite different.
Basically I just want a predictable way to get the difference so that a child object which is on the right of the patent can always stay right of the parent object.
This is the parent component, this update is run every frame:
[Serializable]
public class Component_Parent : BaseComponentAutoSerialization<ISceneEntity>
{
public override void OnUpdate(GameTime gameTime)
{
PassThrough.ParentMatrix = ParentObject.World;
PassThrough.ParentTranslation = ParentObject.World.Translation;
}
}
This next part is the child component:
[Serializable]
public class Component_Child : BaseComponentAutoSerialization<ISceneEntity>
{
Vector3 _parentOffset;
Quaternion _parentQuaternionOffset;
public override void OnUpdate(GameTime gameTime)
{
// Get a sceneobject from the ParentObject
SceneObject sceneobject = (SceneObject)ParentObject;
// This relies on the position never being at 0,0,0 for setup, so please don't do that
// or change it with more look ups so that you don't need to rely on a Zero Vector3 :-)
if (PassThrough.GroupSetupMode || _parentOffset == Vector3.Zero)
{
if (PassThrough.ParentTranslation != Vector3.Zero)
{
_parentOffset = sceneobject.World.Translation - PassThrough.ParentTranslation;
// Decompose World Matrix (Parent)
Quaternion parentQ = new Quaternion();
Vector3 parentSpot = new Vector3();
Vector3 parentScale = new Vector3();
PassThrough.ParentMatrix.Decompose(out parentScale, out parentQ, out parentSpot);
Matrix identity = Matrix.Identity;
// Decompose Identity Matrix (Parent)
Quaternion identityQ = new Quaternion();
Vector3 identitySpot = new Vector3();
Vector3 identityScale = new Vector3();
identity.Decompose(out identityScale, out identityQ, out identitySpot);
_parentQuaternionOffset = identityQ - parentQ;
}
}
else
{
if (_parentOffset != Vector3.Zero)
{
// Decompose World Matrix (Child)
Quaternion rotationQ = new Quaternion();
Vector3 spot = new Vector3();
Vector3 scale = new Vector3();
sceneobject.World.Decompose(out scale, out rotationQ, out spot);
// Decompose World Matrix (Parent)
Quaternion parentQ = new Quaternion();
Vector3 parentSpot = new Vector3();
Vector3 parentScale = new Vector3();
PassThrough.ParentMatrix.Decompose(out parentScale, out parentQ, out parentSpot);
Matrix location = Matrix.CreateTranslation(PassThrough.ParentTranslation);
Matrix rotation = Matrix.CreateFromQuaternion(parentQ);
Matrix rotation2 = Matrix.CreateFromQuaternion(_parentQuaternionOffset);
Matrix newWorld = rotation * location;
Vector3 testTranslation = newWorld.Translation + ((newWorld.Left * _parentOffset.X) + (newWorld.Up * _parentOffset.Y) + (newWorld.Forward * _parentOffset.Z));
Matrix scaleM = Matrix.CreateScale(scale);
//sceneobject.World = scaleM * (rotation * (Matrix.CreateTranslation(testTranslation)));
sceneobject.World = (Matrix.CreateTranslation(testTranslation));
}
}
}
}
I think it has something to do with keeping track of an offset rotation, from the identity matrix and I have started trying to add some code to that effect but really unsure of what next now.
Additional:
If I have the parent object facing the direction of the world space it all works, if it's facing a different direction then it's an issue and the child seems to rotate by the same amount when they are grouped together.
I've uploaded a demo video to try and explain:
http://www.youtube.com/watch?v=BzAKW4WBWYs
I've also pasted up the complete code for the components, the static pass through and the scene entity.
http://pastebin.com/5hEmiVx9
Thanks
Think wheels on a car. I want the right wheel to always be in the same
spot relative to the body of the car.
It sounds like you want to be able to locate the position of the wheel for any given orientation or position of the car. One built in method that XNA has to help here is Model.CopyAbsoluteBoneTransformsTo(Matrix[]); However, your code looks like you want to handle parent child relationship manually. So here is a way to do it without using the built in method. It assumes you do have offset information at load time:
Before the game loops starts (say, in the LoadContent method), after loading the car & wheel and assuming they load into the proper positions, you can then create your offset vector ( _parentOffset )
Vector3 _parentOffset = wheel.meshes[?].ParentBone.Transform.Translation - car.meshes[?].ParentBone.Transform.Translation;//where ? is the mesh index of the mesh you are setting up.
Save that vector and don't modify it.
Later, after the car's matrix has been rotationally and or positionally displaced, set the wheel's matrix like this:
Matrix wheelMatrix = carMatrix;
wheelMatrix.Translation += (wheelMatrix.Right * _parentOffset.X) +
(wheelMatrix.Up * _parentOffset.Y) +
(wheelMatrix.Backward * _parentOffset.Z);
This allows that the wheel matrix will inherit any rotational and translational information from the car but will displace the wheel's position appropriately regardless of car's orientation/position.
The distance between two objects is NOT a function of either orientations.
What you basically want is the distance of the child object to the orientation line of the parent object. Assuming you have a global cartesian coordinate system this can be simply calculated as h=sqrt(x^2+y^2)*sin(Theta), x and y being the relative coordinates of the child with respect to the parent and Theta the orientation of the parent measured from x axis.
But still the question is a little bit confusing to me. If you only want to make sure that the child is on the right side of the parent why don't you simply check the relative x? If it's positive it's on the right and if it's negative it's on the left?
The issue was the way I was trying to use the offset of the world space.
Thanks to flashed from #XNA on EFnet, this code works perfectly:
[Serializable]
public class Component_Child_fromxna : BaseComponentAutoSerialization<ISceneEntity>
{
Vector3 _parentOffset;
Matrix _ParentMatrixOffset;
public override void OnUpdate(GameTime gameTime)
{
// Get a sceneobject from the ParentObject
SceneObject sceneObject = (SceneObject)ParentObject;
// This relies on the position never being at 0,0,0 for setup, so please don't do that
// or change it with more look ups so that you don't need to rely on a Zero Vector3 :-)
if (PassThrough.GroupSetupMode || _parentOffset == Vector3.Zero)
{
if (PassThrough.ParentTranslation != Vector3.Zero)
{
// The old offset - This is just in world space though...
_parentOffset = sceneObject.World.Translation - PassThrough.ParentTranslation;
// Get the distance between the child and the parent which we keep as the offset
// Inversing the ParentMatrix and multiplying it by the childs matrix gives an offset
// The offset is stored as a relative xyz, based on the parents object space
_ParentMatrixOffset = sceneObject.World * Matrix.Invert(PassThrough.ParentMatrix);
}
}
else
{
if (_parentOffset != Vector3.Zero)
{
//Matrix pLocation = Matrix.CreateTranslation(_parentOffset);
//sceneObject.World = Matrix.Multiply(pLocation, PassThrough.ParentMatrix);
sceneObject.World = Matrix.Multiply(_ParentMatrixOffset, PassThrough.ParentMatrix);
}
}
}
}