Add Color to Projection Shader

Questions & Answers
1

So basically i have a working shader that uses the textures color and projects that in a projector. I actually want to add a color attribute so that i can further customize the projection texture.

Here is the projection shader:

Shader "Projector/Transparent Lit/Targeting Reticle" {
   Properties {
	  _Color ("Main Color", Color) = (1,1,1,1)
      _ShadowTex ("Projected Image", 2D) = "white" {}
   }
   SubShader {
      Pass {      
         Blend One One 
            // add color of _ShadowTex to the color in the framebuffer 
         ZWrite Off // don't change depths
         Offset -1, -1 // avoid depth fighting

         CGPROGRAM
 
         #pragma vertex vert  
         #pragma fragment frag 
 
         // User-specified properties
         uniform sampler2D _ShadowTex; 
 
         // Projector-specific uniforms
         uniform float4x4 _Projector; // transformation matrix 
            // from object space to projector space 
 
          struct vertexInput {
            float4 vertex : POSITION;
            float3 normal : NORMAL;
         };
         struct vertexOutput {
            float4 pos : SV_POSITION;
            float4 posProj : TEXCOORD0;
               // position in projector space
         };
 
         vertexOutput vert(vertexInput input) 
         {
            vertexOutput output;
 
            output.posProj = mul(_Projector, input.vertex);
            output.pos = mul(UNITY_MATRIX_MVP, input.vertex);
            return output;
         }
 
 
         float4 frag(vertexOutput input) : COLOR
         {
            if (input.posProj.w > 0.0) // in front of projector?
            {
               return tex2D(_ShadowTex , 
                  input.posProj.xy / input.posProj.w); 
               // alternatively: return tex2Dproj(  
               //    _ShadowTex, input.posProj);
            }
            else // behind projector
            {
               return float4(0.0, 0.0, 0.0, 0.0);
            }
         }
 
         ENDCG
      }
   }  
   // The definition of a fallback shader should be commented out 
   // during development:
   // Fallback "Projector/Light"
}
2

This is the code for a working shader that allows you to tint the original image.

Make sure you have an image with a BLACK backdrop and WHITE graphic and set the texture type to COOKIE/SPOTLIGHT/ALPHA FROM GRAYSCALE.

Shader "Projector/AdditiveTint" {
	Properties {
		_Color ("Tint Color", Color) = (1,1,1,1)
		_Attenuation ("Falloff", Range(0.0, 1.0)) = 1.0
		_ShadowTex ("Cookie", 2D) = "gray" {}
	}
	Subshader {
		Tags {"Queue"="Transparent"}
		Pass {
			ZWrite Off
			ColorMask RGB
			Blend SrcAlpha One // Additive blending
			Offset -1, -1

			CGPROGRAM
			#pragma vertex vert
			#pragma fragment frag
			#include "UnityCG.cginc"
			
			struct v2f {
				float4 uvShadow : TEXCOORD0;
				float4 pos : SV_POSITION;
			};
			
			float4x4 _Projector;
			float4x4 _ProjectorClip;
			
			v2f vert (float4 vertex : POSITION)
			{
				v2f o;
				o.pos = mul (UNITY_MATRIX_MVP, vertex);
				o.uvShadow = mul (_Projector, vertex);
				return o;
			}
			
			sampler2D _ShadowTex;
			fixed4 _Color;
			float _Attenuation;
			
			fixed4 frag (v2f i) : SV_Target
			{
				// Apply alpha mask
				fixed4 texCookie = tex2Dproj (_ShadowTex, UNITY_PROJ_COORD(i.uvShadow));
				fixed4 outColor = _Color * texCookie.a;
				// Attenuation
				float depth = i.uvShadow.z; // [-1 (near), 1 (far)]
				return outColor * clamp(1.0 - abs(depth) + _Attenuation, 0.0, 1.0);
			}
			ENDCG
		}
	}
}