Unity Bilboard shader

   Properties {

      _MainTex ("Texture Image", 2D) = "white" {}
      _ScaleX ("Scale X", Float) = 1.0
      _ScaleY ("Scale Y", Float) = 1.0

   }

   SubShader {
      Pass {  
         CGPROGRAM
 
         #pragma vertex vert 
         #pragma fragment frag

         // User-specified uniforms           
         uniform sampler2D _MainTex;       
         uniform float _ScaleX;
         uniform float _ScaleY;

         struct vertexInput {
            float4 vertex : POSITION;
            float4 tex : TEXCOORD0;
         };

         struct vertexOutput {
            float4 pos : SV_POSITION;
            float4 tex : TEXCOORD0;
         };
 
         vertexOutput vert(vertexInput input)
         {
            vertexOutput output;

            output.pos = mul(UNITY_MATRIX_P, mul(UNITY_MATRIX_MV, float4(0.0, 0.0, 0.0, 1.0))
              + float4(input.vertex.x, input.vertex.y, 0.0, 0.0)
              * float4(_ScaleX, _ScaleY, 1.0, 1.0));
 
            output.tex = input.tex;

            return output;
         }

 
         float4 frag(vertexOutput input) : COLOR
         {
            return tex2D(_MainTex, float2(input.tex.xy));  
         }
 
         ENDCG
      }
   }
}