storing the value in a temporary variable problem

Questions & Answers
1

Hello people,
i want to make a pinball game fully in C#,
i am using the gameion pinball template but rewrite it in C#.
i run into the following problem when firing the pinball:

if (CanUse == true)
{
ControlBallLaunchByKeyboard();
}
else {
// Spring resets back to normal position
if (ballLaunch.localScale.y < 12)
{

		ballLaunch.localScale.y = (ballLaunch.localScale.y + 12.0f) * 0.5f;
		ballLaunch.position.y = (ballLaunch.position.y - 63.00549f) * 0.5f;
	}		
	}
}


private void  ControlBallLaunchByKeyboard (){
if (Input.GetKey(KeyCode.DownArrow))
{
	// When the player holds down the Down Arrow button, pull down the ball launch
	if (ballLaunchForce < 2000)
	{
		float dt = Time.deltaTime * 8.0f;
		ballLaunchForce += dt * 180;
		ballLaunch.localScale.y = Mathf.Lerp(12.8f, 1.8f, ballLaunchForce / 2000);
		ballLaunch.position.y = Mathf.Lerp(-63.1f, -68.6f, ballLaunchForce / 2000);
	}
}
else
{
	// Spring resets back to normal position
	if (ballLaunch.localScale.y < 12) 
	{
		ballLaunch.localScale.y = (ballLaunch.localScale.y + 12.0f) * 0.5f;
		ballLaunch.position.y = (ballLaunch.position.y - 63.00549f) * 0.5f;
	}
}

i get allot of the following errors:

  • Assets/Scripts/Trig.cs(43,36): error CS1612: Cannot modify a value type return value of `UnityEngine.Transform.localScale’. Consider storing the value in a temporary variable
  • Assets/Scripts/Trig.cs(44,36): error CS1612: Cannot modify a value type return value of `UnityEngine.Transform.position’. Consider storing the value in a temporary variable

Could anyone point out what i am doin wrong or help me ??

thanks in advance

2

Hi,

transform.localScale and transform.position are properties, in C#. So, you can get those vector3, you can set those vector3, but you can’t dirrectly modify members of those vector3.

A solution is to use a temporary variable, and replace lines like :

ballLaunch.localScale.y = (ballLaunch.localScale.y + 12.0f) * 0.5f;

by

Vector3 temp = ballLaunch.localScale;
temp.y = (ballLaunch.localScale.y + 12.0f) * 0.5f;
ballLaunch.localScale = temp;