koobas.hobune.stream
How to make simple tilting function on the iPhone
Hi,
I'm trying to create a simple tilt function using the iPhone's accelerometer in Unity. I've looked at a lot samples but can't get it to work the way I want. My App basically has a 2D character. What I'm trying to do is:
//pseudocode if(tiltleft > 0) { //do something }
if(tiltright > 0) { //do something }
Could someone advice me on how to approach this or point me to a good tutorial on accelerometers please?
Thanks in advance,
Hakimo
There's a decent example for multi-dimensional tilt functionality in the iPhone Unity documentation, but I actually just messed around with getting this working in my project last night.
I think we have the same problem - apply the tilt along X to the X coordinate of our character in a 2D plane. Here's how I got it working... This is in C# and is based on the iPhone controls documentation.
public float TiltSpeed = 5.0f;
void FixedUpdate() { float tiltAngle = iPhoneInput.acceleration.x;
tiltAngle *= Time.deltaTime;
tiltAngle *= TiltSpeed;
// Move object - Change this to transform.position if you don't have a rigid body on your char.
rigidbody.AddForce(tiltAngle, 0, 0);
}
Obviously, you need to test this on the device or with Unity Remote. I actually have a script that displays my devices tilt amount onGUI so I can see precisely what kind of X values the device is returning.
Wow, that looks easier than what I have tried. I even got to see the values as well. Although I'm a bit stuck at the moment with the if conditions. I'm using print(transform.position.x) to get the values. I tried to use: if(transform.position.x == -0.1) { //do something } Unfortunately nothing works. What value should the conditions be? I even used tiltAngle but nothing happens.
Thanks again,
It's alright, manage to do something. I didn't check the value properly for it to make any effect. Thanks again. Also, where did you learn about accelerators? The one example I followed earlier made so many variables that I didn't quite understand what it was doing :P
This is all modified from the Help documentation in Unity under the iPhoneInput script reference. I do think the example could have been simpler, but I guess they wanted to show that generally for a ball rolling around you would want to be polling at least two coordinates.
Thanks again. Just wanted to understand more about the coding; How does the float TiltSpeed effect the tilt? I can't seem to see any dramatic changes. Also, when you assigned TiltSpeed to tiltAngle, does it override the Time.deltaTime? I didn't know you can assign 2 values to a variable. Thanks again for the help :)
Hi Hakimo,
Float is a type of number that can hold decimals. Since the Input is a decimal number, it's perfect for holding the X Acceleration.
In the next two I'm multiplying the TiltAngle. $$anonymous$$ultiplying movement deltaTime is a way of ensuring that you move based on the time and not by Frames (which can vary by FPS). Second, I multiply by our tilt speed which is the variable that affects how much our character moves based on the tilt.
As Smorpheus suggested, to use the accelerometer I've got the Controller.js from Unity's Roll-a-ball iPhone example: http://unity3d.com/support/resources/example-projects/iphone-examples.html
Maybe it's not exactly what you needed, but I guess it's related enough, a good hint and good to document. It's quite simple and I even simplified it a little:
public float force = 9.8f;
void FixedUpdate () { dir.x = Input.acceleration.x; dir.y = Input.acceleration.y; Physics.gravity = dir * force; }
