Demo 25 - Fixed tessellation

Shader "Custom/FixedTessellation" {
    Properties {
        _MainTex ("Main Texture (Diffuse)", 2D) = "white" {}
        _BumpTex ("Normal Map", 2D) = "bump" {}
        _DispTex ("Displacement Map", 2D) = "gray" {}
        _TexVal ("Tessellation value", Range(1,40)) = 1
        _DispVal ("Displacement factor", Range (0, 1)) = 0
    }
    SubShader {
        Tags { "RenderType"="Opaque" }

        CGPROGRAM
        #pragma surface surf BlinnPhong vertex:vert tessellate:tess
        #pragma target 4.6

        struct appdata {
            float4 vertex : POSITION;
            float3 normal : NORMAL;
            float4 tangent : TANGENT;
            float2 texcoord : TEXCOORD0;
        };

        float _TexVal;

        float4 tess() {
            return _TexVal;
        }

        sampler2D _DispTex;
        float _DispVal;

        void vert(inout appdata v) {
            float val = tex2Dlod(_DispTex, float4(v.texcoord.xy, 0, 0)).r * _DispVal;
            v.vertex.xyz += v.normal * val;
        }

        struct Input {
            float2 uv_MainTex;
        };

        sampler2D _MainTex;
        sampler2D _BumpTex;

        void surf (Input IN, inout SurfaceOutput o) {
            half4 c = tex2D (_MainTex, IN.uv_MainTex);
            o.Albedo = c.rgb;
            o.Normal = UnpackNormal(tex2D(_BumpTex, IN.uv_MainTex));
        }
        ENDCG
    }
    FallBack "Diffuse"
}