change material on object when touched.

Question

Hi guys i've written a short script for a VR project I'm doing, its basically a highlighting tool.

so when I point towards an object it moves a sphere to the end of my pointer. the sphere then highlights the object it is touching (changes its colour). and gives me some info.

 // the Color Change Script Snippet on the sphere
  void OnTriggerEnter( collider other)
     {
     other.gameObject.renderer.material.color = Color.blue
     }

My problem is, when I touch something without a renderer it crashes and brings up an error.

is their a way I can say;

 if object has renderer  - turn blue
 
 else ignore

I'm also hoping to change the colour back using OnTriggerExit, if anyone knows how to do that, it would also be helpful.

Thanks in advance!!!

Lee

Answer 1

Accessing the Renderer only if it exists

gameObject.renderer is deprecated (just like .rigidbody, .collider, etc). Instead, you need to use GetComponent.

 Renderer renderer = other.GetComponent <Renderer> ();
 if (renderer != null)
 {
     // Change color
 }

Restoring the original color on TriggerExit

Let me know if the code comments do not explain well enough what's happening.

Solution 1: Only one object can be affected at a time

 private Renderer  touchCurrentRenderer; // The Renderer that belongs to the object that the pointer is currently touching
 private Color     touchOriginalColor;
 public  Color     touchHighlightColor;
     

 // Has to be "Stay" instead of "Enter", if you have overlapping objects
 private void OnTriggerStay (Collider other)
 {
     // If the pointer is not touching an object.
     // This if statement prevents the pointer from affecting multiple objects simultaneaously
     if (touchCurrentRenderer == null)
     {
         // Get Renderer component
         touchCurrentRenderer = other.GetComponent <Renderer> ();

         // If the touched object has a Renderer Component
         if (touchCurrentRenderer != null)
         {
             // Save the Original Color
             touchOriginalColor = touchCurrentRenderer.material.color;

             // Highlight Object
             touchCurrentRenderer.material.color = touchHighlightColor;
         }
     }
 }


 private void OnTriggerExit (Collider other)
 {
     if (touchCurrentRenderer != null)
     {
         // Restore the Original Color
         touchCurrentRenderer.material.color = touchOriginalColor;
         touchCurrentRenderer = null;
     }
 }

Solution 2: Can handle multiple objects simultaneously

There are, of course, several ways to solve this. I chose the one that, in opinion, is easiest to understand and manage.

It simply adds a component to the touched objects which contains the original color and removes the component on TriggerExit.

Another solution is to use a collection (List, Dictionary, etc) combined with a custom class/struct to hold the data (renderer reference and original color), but you risk running into serialization problems which can be quite tricky to fix.

Here's the simple solution (using a custom component called TouchObjectData).

Pointer script:

 public class Pointer : MonoBehaviour
 {
     public  Color  touchHighlightColor;


     private void OnTriggerEnter (Collider other)
     {
         // Get Renderer component
         var renderer = other.GetComponent <Renderer> ();

         // If the touched object has a Renderer Component
         if (renderer != null)
         {
             // Get TouchObjectData component
             var touchObjectData = other.GetComponent <TouchObjectData> ();

             // If the object does not have a TouchDataObject component
             // (Meaning: If this object hasn't been handled yet)
             if (touchObjectData == null)
             {
                 // Add a new TouchObjectData component to the touched object
                 touchObjectData = other.gameObject.AddComponent <TouchObjectData> ();
                 
                 // Save the Original Color on the new component
                 touchObjectData.originalColor = renderer.material.color;

                 // Highlight Object
                 renderer.material.color = touchHighlightColor;
             }
         }
     }


     private void OnTriggerExit (Collider other)
     {
         // Get Renderer component
         var renderer = other.GetComponent <Renderer> ();

         // If the touched object has a Renderer Component
         if (renderer != null)
         {
             // Get TouchObjectData component
             var touchObjectData = other.GetComponent <TouchObjectData> ();

             // If the object has a TouchDataObject component
             if (touchObjectData != null)
             {
                 // Restore the Original Color
                 renderer.material.color = touchObjectData.originalColor;

                 // Remove the TouchObjectData component
                 Object.Destroy (touchObjectData);
             }
         }
     }
 }

TouchObjectData script:

 // This component will be added to touched objects through code.
 // Do not manually attach this script to objects in the editor.

 public class TouchObjectData : MonoBehaviour
 {
     public Color originalColor;
 }

Answer 2

Answer by Tazza08 · Jan 07, 2019 at 03:40 PM

Thanks, I knew it would be relatively simple.

I will try it on the game later.

Add comment · Share

change material on object when touched.

2 Replies

Accessing the Renderer only if it exists

Restoring the original color on TriggerExit

Your answer

Follow this Question

Related Questions