My main character moves by touching and holding him and then moving your finger left or right to move the character. To do this I just simply update the node's x position (walks left and right on a flat surface) in touchesMoved() with the x position of the touch location, and apply an animation depending on the direction he's moving.
I want to kind of take this to the next level and accomplish the same effect, but using physics, so that when I'm done moving him and release my finger, he may slide a little bit in the direction he was moving given the speed I was moving him at, if that makes sense. Does anyone know how I can accomplish this effect?
Would I have to do as I'm currently doing and update the position as it moves, but also apply a force/impulse at the same time? Kind of confused on how to approach this
Moving the physics body via force, impulse, or velocity will automatically update the player position.
So you will have to play around with the correct way to accomplish your goal. But based on this, what I would suggest is replace your .position code with .physicsBody!.velocity code in your touchesMoved. Then, on your touchesEnded, you can apply a bit of an impulse to give the player that little bit of an "on ice" effect to keep them going a tad.
You will need to experiment with how much velocity you want to get the character to move at the correct speed, and then you will need to play with the impulse figures as well to get it just right.
This could get a bit tricky though, in touchesMoved... because at some point you will want to reset the velocity to 0 (so they stop moving when your finger stops).
To do that, you will need to to use the .previousLocation from your touch object, and compare the distance of X moved. if the distance X moved is >0 (or some deadzone threshold) then apply the velocity; if the deltaX is 0, then set the velocity to 0.
This may actually be more complicated than just using .position to move the character, then having the character slide a bit with physics on touchesEnded.
You will have to play with it to get it right.
Related
I have been working on a Unity ping pong game using the Leap Motion. I use rigidbody.MovePosition() to move the paddle. However, when I hit the ball (which uses gravity), the paddle launches it too far. Even when I change the masses of both, it doesn't do anything.
What variable should I change to reduce this energy going into the ball?
From the following link.
"MovePosition will put your object at the target location, no matter what. It may push aside other objects in a realistic way, or may blast them out of the way, or may just pass right through them. But it will gladly move you through a solid wall or a mountain.
If you're using MovePosition on a rigidbody to add from where you currently are, it looks like AddForce. With AddForce, the physics step does all the work: applies your velocity, sees the collision and handles the bounce. With MovePosition, the physics step sees you're mysteriously overlapping a solid object. If it isn't too much, it will bounce you apart."
You won't need to use MovePosition. Instead, you can figure out the direction of the shot (based on the position of the ball relative to the paddle). Then you can add an impulse force in that direction to the ball.
Pseudo-code (from the following link):
Vector3 shootDir = ballPosition - paddlePosition; // Calculate direction of the shot
shootDir.Normalize(); // Normalize the shot vector
ball.AddForce(shootDir * speed, ForceMode.Impulse); //Add impulse force in correct direction.
Credit due to Owen Reynolds and Tim Michels.
I'm using the first person controller for my characters movement. On a left arrow keypress, I'd like the character to instantly rotate 90 degrees and keep moving forward. Currently, when I hit the arrow key, the character makes the sharp 90 degree turn, but the forward momentum the character previously had takes a second to wear off so the character ends up sliding in the direction he was previously moving a short bit.
The closest example I can think of to visually explain what I'm trying to do is how the character turns sharp in Temple Run. How my game is currently working, if I had the character on a ledge make a sharp left turn, he'd likely keep the original momentum and slide off the edge right after he turns.
Since my character is running on the x/z axis, I'm wondering if there would just be some way to maybe swap the directional velocity/momentum? The speed the character had on the x axis would instantly be switched to the z when it turns and the other would be set to zero. I'm obviously open to any solution that accomplishes what I'm looking for.
I dug into the CharacterMotor class in the first person controller, but have yet to find what part I can tweak to accomplish this.
I'd greatly appreciate any help.
Thank you.
You can try to stop the velocity of the Rigidbody before turning.
this.rigidbody.velocity = Vector3.zero;
this.rigidbody.angularVelocity = Vector3.zero;
If you want the object to continue like it did, you can try playing around with it by saving the current velocity in a variable, setting it to 0, rotate it and then putting back the old velocity (still forward).
If it works with global vectors (so from the point of view of the world, not the object), then you can try negativing the velocity, actually causing it to go 'backwards'. I can't test it for now but either way I think you need to set the velocity to zero first before turning the character.
I use Unity3D and I have a player with a rigidbody. I add force tto the body for moving the player. My player walks over a terrain but is able to walk up mountains that are to steep to climb. I want to limit the player so it cannot walk up a slope that is to steep.
I know there is a CharacterController component that has this functionality, but I have to use the rigidbody, so I want the same but on my rigidbody.
I can get the normal of the triangle I am standing on, and calculate its angle, but I cannot seem to make the player stop moving up the slope. Only make the player stop moving (which makes the player unmovable once it hits a angled slope)
Any ideas how to solve this problem?
It's difficult to answer without more details on how you're using the physics engine. How/Are you using friction? What angle are you applying the force? Is it always horizontal or at the angle of the floor? Does the player have a mass?
Anyway I can think of a few ways to solve this
Go the pure physics route. Using player mass, friction, force angle, gravity, etc. Get the physics to handle these situation for you. This may take a fair amount of time and programming.
Keep the rigid body but fake the forces. Scale the force you are applying to the body of the player with the angle of the triangle the player is on. You can either use trigonometry to work out what you should apply or your own mapping. By your own mapping I mean set an angle where 0 force is applied (say 45 degree) and do a linear(or non linear) scale on the force applied so on flat ground force is 1 and at 45 force is 0.
Don't use rigid bodies. There is a reason most games don't use rigid bodies to control characters. It's hard and complicated and most of the time not worth the time it would take. Of course I don't know the details of your project so if this isn't an option, fine.
Hope that gives you some things to think about.
so I have a ball (sprite subclass) that can be dragged around the screen and updates it body to tell the world its position.
The problem is, when I apply a force to the ball while the ball is being touched (thus being controlled by a finger), I have two pieces of code fighting against each other to update the sprite's visual position.
The world stepper is trying to follow through the physics and update the ball's position. The touch methods however are also trying to update the ball's body and graphic position. Ideally, when touched I would like to kill off any physics affecting the ball.
So what exactly should I be trying to do to consolidate this? This is also creating issues for collisions and filtering. Any help appreciated. Thanks
Do you want the ball to have an accurate physics simulation? If not, you could always use the SetTransform method of the b2body class like this.
CGPoint ballLocation = ;//use the touched location for this
b2Vec2 vecBallLocation = b2Vec2(ballLocation.x / 32, ballLocation.y / 32);//calculate this on your own
b2Body * ballBody = ;//replace this variable with your ball's b2Body;
ballBody->SetTransform(vecBallLocation, ballBody->GetAngle());
Do not set the ball sprite's position manually. Leave this up to the physics simulation. Your code will get really messy over time if you have to keep track of what sprites you set the position of manually and which ones use the physics simulation to update their positions. This way is also much easier.
When the physics object is being dragged, set its velocity and angular velocity to 0,0 before running the physics step simulation. You may also want to temporarily get the physics object's position, then step, then set the body's position back, then apply whatever touch dragging offset you got from moving the finger to the body.
I currently have a SneakyJoystick up and running. It works fine, it moves the sprite around the screen. I already have it so it will flip the sprite's image when the joysticks degrees is to the left. But how do i make it so if it was moving left and then becomes inactive, the sprite won't automatically flip back? This is really confusing to me. Any help is appreciated. Thanks.
You must have a scheduled selector function in your program that checks the movement of your joystick after every second (or whatever the interval). I mean the code where you are checking if the joystick is towards left (joystick.velociy). So this selector will be called continuously, no matter your joystick is active or not. So when your joystick moves to left, you can flip the sprite and you can set define a boolean flag "isFlipped=true". And in the same selector method that you can check if joystick is not moving and "isFlipped=true" then you can flip back your sprite and set the flag false.
Generally speaking, it is advised to multiple the velocity by an arbitary amount and the delta value passed in to the update routine so that things move more smoothly. That will ensure that the final movement of the player is OK. I have seen people use a value between 50 and 200 for average movement.
eg,
CGPoint velocity = ccpMult(moveStick.velocity, 200 * delta);