How can I detect collision coming from outside and not detect collision coming from inside to outside
I have a game when a player fires a bullet it returns after a while like a boomerang. But my problem is that it should NOT detect a collision when the bullet is coming from the player but it should detect collision when the bullet is returning. I've tried oncollisionenter2d and ontriggerenter2d but it's not working
You could check the direction of the bullet and react (or ignore) accordingly. The exact implementation depends on how you are moving the bullet.
If you are using a Rigidbody, you have access to the Vector3 velocity field, which you can multiply with the bullet's distance from the player with Vector3.Dot(). If the result is negative, then the two vectors are pointing in opposite directions (which means the bullet is moving away from the player) and you simply return from the OnCollisionEnter call.
Related
I have a bullet game object and an enemy game object.
I want to have the ability of getting the collision point/contact, which's why I think I need the collider of the bullet to not be a trigger collider - this way, I want to have the bullet bounce off the enemy. At times, the bullet will need to bounce off of rectangular objects (not a problem), but I also want the bullet to bounce off of elliptic objects (the problem).
I want the bullet not to "physically" push the enemy, which is why, intuitively, I should set the bullet's collider to be a trigger collider.
When the bullet's collider is a trigger collider, I seemingly don't have a way to implement the bouncing.
But when the collider's not a trigger collider, it pushes the enemy object.
There's no code errors, but I think the code hasn't got anything to do with the problem.
I suspect the problem may have something to do with the Physics Collision Matrix.
EDIT
It seems that raycasting would be the solution to the problem, as Leoverload proposed. My problem became a different problem now, so I'll close off this thread, and open a new one.
Thanks for the help, #Leoverload ! :D
For the position of the hit it's very easy. You must have 2 colliders and 2 Rigidbody and then you can simply add a
Void OnTriggerEnter2D(Collision Coll) and inside it check for the tag : if(coll.compareTag("surface")) and inside you can get the position with collision.transform.position.
The collision matrix on the Physics menu only allows to remove Collision between certain layers, it's useful if you want the enemies not to push eachother!
If you don't want the player pushed you can change the collider to trigger, and destroy the bullet just after the collision with the same method as before with a void OnTriggerEnter2D and the compareTag. In this way it will look like it touches the enemy and explode, but it won't actually touch anything. If you want to add knockback to the player then you could do a simple AddForce based on the direction of the bullet and the work is done!
If you want to avoid the bullet to move walls you can set walls to static and it should work fine
I am making a game in unity. I have a tank it's got a rigidbody. I am using transform.translate to move it. When it gets hit by a shot it moves backwards. If use the joystick to move it forward it moves with reduced speed. If I let go of the joystick it continues moving backward.
Please help.
There is not much to go in your question but I'm quite certain you're moving the character with transform.translate (like you wrote) but you have a Rigidbody attached to the GameObject, which uses physics.
So when your GameObject gets hit by a projectile the physics will move it backwards, and you will "teleport" the GameObject with the inputMovement, but that does NOT affect physics.
If you don't want to use physics and are only interested in the collision, you should disable the physics simulation on the Rigidbody compontent.
So go ahead and set the Is Kinematic checkbox in your rigidbody to true.
And, if interested, the value affecting physics is the velocity of the Rigidbody:
GetComponent<Rigidbody>().velocity
You need a Rigidbody on one of the colliding objects, personally I put it on the player but use velocity to handle movement to make sure it works nice with collision physics. When using transform.translate your character will essentially teleport X units every frame, giving the illusion of movement but not actually physically moving. This can make things like teleporting through walls, etc, happen.
So I've told you how to solve your immediate problem, my suggestion is that you re-write your movement logic to use Rigidbody.velocity instead. Your movement seems simple so it's practically just replacing your transform.translate with this:
rb.velocity = joystickInput * speed;
I'm using Unity and i am doing a pong game. I would like to be able to move the paddles with the mouse key. I have tried just moving their position but that of course will simply "teleport" them through the colliders along the edge of the playing field. I tried using addForce() and making the rigidbody fixed in the x position, however, what happens is when the ball hits the paddle, it pushes it and the paddle snaps back. All of the ball's energy is lost (there is gravity in my game). How can i move this box collider but not let it over lap other box colliders while moving? Thanks!!!
Your paddle should be a kinematic (IsKinematic parameter) rigidbody (attached RigidBody2D) collider while the edges should just be a static collider. But, you should control the limits/edges of paddle movement within your script.
If you do things this way, your ball will naturally bounce of the edges and off your paddle. If, however, you want the ball to pass through the edges but notify you of doing so (e.g. lose condition), you should make the edges a static trigger collider (IsTrigger parameter).
Here's a detailed list with all interactions between different types of colliders: http://docs.unity3d.com/Manual/CollidersOverview.html. The messages generated are passed via 2 different functions: OnTriggerEnter2D and OnCollisionEnter2D.
So I'm new to Unity and I'm sure I'm missing an easy step, but after looking online for a while for some reason I can't find the solution.
I have two objects on the screen, player and enemy. Both have Rigidbody2D, and Box Collider 2D attached. On Box Collider 2D I have clicked is triggered On Rigidbody2D for both I have clicked Is Kinematic. On player I have a simple movement script. On the enemy object I have this:
void Update () {
RaycastHit2D hit = Physics2D.Raycast(transform.localPosition,transform.right,Mathf.Infinity);
Debug.DrawRay(transform.localPosition,transform.right);
if (hit)
Debug.Log(hit.collider);
}
Now for some reason when I move player over the object if (hit)
is true, but if I move the player anywhere on the right side it is not true. What would be the reason for this? Thanks.
First of all you don't need Rigidbody for raycast detection, only colliders. Second, Physics2D.Raycast uses world position, not local, so replace "transform.localPosition" with "transform.position", this messes it up a lot if the transform is child of something. Take in mind that you are sending raycast from the right side of your transform, so maybe it's not hitting anything and values you are getting are actually correct.
In my game the player running in forward direction on a path triggers the collider to instantiate the enemies, when the same player comes in opposite direction and triggers the collider i dont want the player to instantiate enemies. How to achieve this please help..
When I read your question, I see two possible situations here:
The player is only allowed to trigger when moving forward through it.
The player is only allowed to trigger when coming from a certain direction.
The first one would be quite easy. You can get the movement direction from the character controller to see if he's moving forward. You can for example try to use Transform.LookAt and compare it with the rotation of the player.
The second one is approached differently. For example, your trigger may only respond when the player moves forward along the x-axis. Then you record the X position as the very last thing in your movement loop. Then compare your X position in the next frame with the position in the last frame. If the difference between them is positive, you are moving in a positive direction. If negative, your moving in a negative direction.