Fairly simple question that Im sure you will laugh at me for.
I have two rectangles playerRect and wall.
I have an if statement with the condition being ..
if (CGRectIntersectsRect(playerRect,wall)) {
//handle collision here
}
The problem I'm having is working out which side actually hit the wall rectangle.
I need to know because then I stop te player from moving depending on which side hit.
Thanks for any help
Disco
I would add some direction property to my 'Player' object. This way when you detect a collision, you just check to see which way the player was moving prior to the collision and react accordingly.
Create a CGRect for each side of your object with just a width of 1 (or height of 1 depending on the side) and look for intersections with the sides instead of the entire object. If your object is moving faster than 1 pixel per collision check, then you would check the sides in addition to checking the entire object
Related
So, lets say my character has the ability to push "movable" objects. This is alredy implemented and working as desired.
But I want to make the characher be pushed back if he tries to push an object that is hitting a wall or an immovable object, is there a way to see if my add impulse had any effect?
Or a best way to do is some ray casts on the movable object boundaries to see if is touching any other thing?
For characters you can use Launch Character. It's like adding velocity giving a specific direction. Add Impulse is intended to be used with Objects that simulate physics.
Just Launch the Character to a direction opposite the direction it's touching. You can use Dot Product between Character Velocity and the Object Face (forward).
I have a cube with Rigidbody attached to it would slide slightly whenever I pressed the play button. If I leave it for awhile, it would slide to other side of the screen.
Anyone know how to solve this problem without using the "freeze position"? I don't know what I messed up in my project...
This is what the object looks like:
Note: I need to use the gravity.
Thank you!
Heh! The solution here is:
You had a rigidbody on the floor :)
You don't do that :) Never.
If the "floor" surface is flat, then,
it will not slide.
You've got something strange going on, such as
"floor" is NOT flat
a feature like "Wind" turned on
perhaps other objects invisible in the scene you have forgotten about are nudging it
PhysX does not have a "mind of it's own". There is some simple reason it is moving.
Let's say the "floor" is indeed on an angle, so it SHOULD move, but you WANT it to NOT move.
What you obviously do:
Just as in the real world, put something there to stop it moving.
A small invisible wall will do the trick. That's PhysX!
Usually rigidbody sliding happens when a lower rigidbody has lower mass than a higher rigidbody (forcing down the lower rigidbody). Typical problem with player having say mass 80 jumping on a cube with mass 1. In this case the collision is so violent that the cube will probably fly out (not only slide).
The situation is very similar to the real world. Try to stay on a box of milk if you have 120 kg (ok, ok, 80 :) ).
When you try to eliminate this behavior, you need either increase the mass of the lower object or decrease the mass of the higher one or set the lower rigidbody to kinematic.
The solutions above is not proper way of solving the problem. Unity has more features of physics than mass. If you get sliding on movement or because of other objects you should add proper drag value on your rigidbody. For example , lets say you have blocks spawning over top of other blocks and this creates horizontal sliding. In my case I add drag of 1 to the objects which has mass of ~ 1 kg. It depends on the scene and you should try different values on your case. Do not use bigger values and angular drag if it is not important.
I have an object that, after receiving its respective input, it moves this way:
mov = new Vector3((Input.GetAxis("Horizontal") * vel), 0, 0);
transform.position += mov;
But, I want it to bounce back, once it collides with an object.
I´ve made the procedures already (OnCollisionEnter2D(Collsion2D col){bla bla...}), but I need help with what happens on the collision (bouncing back the object)....
I´ve tried giving the collided object a bouncing material, but it just slows it a bit, my guess is that because of the constant force given by the acceleration.
Greetings.
If you move the object with transform.position what you are doing is basically a "teleport" so it will ignore the bouncing material. If you want it to bounce you have to write the physics code to detect a collision and change the movement or you can do addforce to move the object and it will detect collisions and react automatically.
you are teleporting the object at the current time. instead you should use the Rigidbody.addForce this will add a force in the specified direction thus if you do the opposite direction will "bounce" of the object. Another option would be to create a physics material then not bother with the code.
You are not using materials, right?
See if the content of this post may help you, the OP is using a formula using Raycast and the answer guides him to use the Raycast with Layers Maks:
2D bouncing formula doesn't work properly
There is this one also with fixed angles (like Pong), but it uses material (with values: friction: 0, bounciness: 1):
https://gamedev.stackexchange.com/questions/70294/get-gameobject-to-bounce-of-colliders
But if nothing makes sense and you are going crazy and might want to start from zero, there is this official video tutorial on bouncing and sliding in 2D:
https://unity3d.com/learn/tutorials/modules/beginner/2d/sliding-bouncing-2d
I have a sphere build from multiple objects. What I want to do is when I touch/click an object, that object should find all adjunctive objects. But because none off them are moving, no collision detection can be used.
I can't find a way to detect these adjunctive objects even when the colliders do collide with each other, as I can see that in the scene. I tried all the possibilities, but none off them are working, because no objects are moving.
Is there a way to check for manual collision detection, or is there some sort of way to let Unity3d do the collision detection automatically?
You could keep a list of all those objects, then when your event happens you can send messages to all them to do what you want them to do.
Lets assume you want your sphere to break into little pieces. You send a Force message to the sphere. Then you use Newton's Laws of motion and find out how much velocity each piece gets. Remember velocity is a vector thus it has direction.
This is how I would do it and still keep the right amount of control over what happens in my game/simulation. Remember F = ma.
you could use RaycastHit (http://docs.unity3d.com/Documentation/ScriptReference/RaycastHit.html) for your collision, this also works on non-moving objects but it needs more performance
You can add rigidbody to every objects; when you touch one of them, give a force onto it, then it is going to move and trigger event of the adjacent objects.
for the reason you do not want to move the object you touch, you can cancel movement in the OnCollider or OnTrigger event handler function.
I managed to work around this by checking the distance from the selected object and all other objects that are part of the sphere. If the distance is below a certain value, then it is an adjunctive object.
Although this is certaintly not fool proof, it works without problems so far.
I am sorry I was not clear enough. Thanks for all the advice what so ever.
I am trying to make a snake kind of game on the iPhone. For that I plan to have a simple dot as the sprite which draws a line. The dot is controlled by two buttons on the left and the right of the screen enabling it to turn left or right. Now I really do not have any idea how to make the sprite move automatically forward and how to program the turning. It should not be exactly as in snake where it abruptly turns left or right but it should more be a smooth curve. I hope you're getting my point and I'd appreciate all kinds of thoughts! Thanks a lot!
Somewhat trying to make it like this:
http://www.bnet.im/images/screen_curve.png
There are a lot of ways of doing this, but one simple way would be to store the angle of the snake's trajectory (I've called it theta) and move it a fixed amount in every call to Update.
Assuming that the snake class inherits from CCNode:
-(void)Update:(ccTime)dt {
self.position = ccp(self.position.x + cos(theta)*dt,
self.position.y + sin(theta)*dt);
}
You could then update theta from your event handling logic by increasing it or decreasing it when the user taps to turn left or right.