50% transparent when overlapping shader.

[Shbli]

Hi,

I have a basic click pointer for my game, basically what I need is that part of that pointer get blocked by another 3D object, it should render that part on top of it with 50% transparent.

For example, this screenshot:

[32715-2014-09-21+12_47_30-unity±+defaultscene.unity±+the+royal+quest+unity+3d±+iphone,+ipod+touch+and+i.jpg|32715]

50% of the blue pointer is covered by the stairs, what I want is to show that 50% part as 50% transparent to complete it.

I have no issues getting a paid shader from the assets store, not sure how to search for a shader like that. As I have no experience writing shaders.

What the shader need to do is something really basic

1- Draw the clicked pointer as it would usually normal with 50% opacity

2- Draw it second time without a Z Test (or with) so that it’s always on top, but that second time it will be drawn with 50% opacity of it’s original opacity

so, when the two appear on top of each other, I have a higher opacity pointer, when one disappear or part of it, I have a 50% opacity pointer!

Thanks!

[tanoshimi]

Try this:

Shader "Custom/Overdraw" {
Properties {
	_MainTex ("Base (RGB) Trans (A)", 2D) = "white" {}
}

SubShader {
	Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"}
	ZWrite Off
	Blend SrcAlpha OneMinusSrcAlpha 
	
	// Include functions common to both passes
	CGINCLUDE
		struct v2f {
			float4 vertex : SV_POSITION;
			half2 texcoord : TEXCOORD0;
		};
			
		#pragma vertex vert
		#pragma fragment frag

		#include "UnityCG.cginc"
		sampler2D _MainTex;
		float4 _MainTex_ST;
			
		v2f vert (appdata_base v)
		{
			v2f o;
			o.vertex = mul(UNITY_MATRIX_MVP, v.vertex);
			o.texcoord = TRANSFORM_TEX(v.texcoord, _MainTex);
			return o;
		}
	ENDCG

	// Pass for fully visible parts of the object
	Pass {  
		ZTest LEqual
		CGPROGRAM
			fixed4 frag (v2f i) : COLOR
			{
				fixed4 col = tex2D(_MainTex, i.texcoord);
				return col;
			}
		ENDCG
	}
	
	//Pass for obscured parts of the object
	Pass {  
		ZTest Greater
		CGPROGRAM
			fixed4 frag (v2f i) : COLOR
			{
				fixed4 col = tex2D(_MainTex, i.texcoord);
				col.a *= 0.5;
				return col;
			}
		ENDCG
	}
}
}