Add Color to Projection Shader

Question

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"
 }

Answer 1

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
         }
     }
 }

Add Color to Projection Shader

1 Reply

Your answer

Welcome to Unity Answers

Follow this Question

Related Questions