Fading alpha of quad with unlit alpha texture

Unity Engine
1

Having some difficulty changing alpha over time (deltatime of Update) on a quad that has a texture (icon) applied via Unlit texture with alpha (png)

Basically this:

public float _maxtime = 2.0f;
private float timer = 0.0f;
private Color colorAlpha; // fade amount for interaction icons

void Start () {
        colorAlpha = footIcon.GetComponent<Renderer>().material.color;
    }

void Update () {
timer += Time.deltaTime;
// set icon fade to reflect how long it has been looked at
colorAlpha.a =  Mathf.Min (timer/_maxtime + 0.5f, 1.0f);
footIcon.GetComponent<Renderer>().material.color = colorAlpha;

}

This doesn’t appear to do anything. Is there a separate way I have to call to change alpha on the texture image (icon.png) itself?

Weird Transparency
2

Besides that you should cache the Renderer component so you do not need to look it up each frame the code should work.
Make sure you have a shader that support Transparency via the Main color.
The Unity Unlit shader do not have a variant with A texture + Transparency via the color attribute.
This shader from the unity wiki should work fine for you.

http://wiki.unity3d.com/index.php/UnlitAlphaWithFade

Shader "Unlit/UnlitAlphaWithFade"
{
    Properties
    {
        _Color ("Color Tint", Color) = (1,1,1,1)   
        _MainTex ("Base (RGB) Alpha (A)", 2D) = "white"
    }

    Category
    {
        Lighting Off
        ZWrite Off
                //ZWrite On  // uncomment if you have problems like the sprite disappear in some rotations.
        Cull back
        Blend SrcAlpha OneMinusSrcAlpha
                //AlphaTest Greater 0.001  // uncomment if you have problems like the sprites or 3d text have white quads instead of alpha pixels.
        Tags {Queue=Transparent}

        SubShader
        {

                   Pass
                   {
                        SetTexture [_MainTex]
                        {
                    ConstantColor [_Color]
                               Combine Texture * constant
                }
            }
        }
    }
}
1 Like
3

Awesome, thank you so much for the help!

4

Hmm, tried it out, but will have to either keep looking, or learn more about shaders (so handy, yet my weakest skill when it comes to all of this…); the problem is that my icon is a .png with alpha layer/color, so that needs to be transparent (in addition to being able to change the overall alpha); doesn’t seem to work that way with the above shader

Maybe if I research enough about shader programming I can make it work (I hope)

5

If the GameObject is a UI image you need to use () not ().

And I see I’m 2 years late with my reply.