Demo 12 - Pixelation

Shader "Custom/Pixelation" {
    Properties {
        _MainTex ("Base (RGB)", 2D) = "white" {}
        _PixelNumberX ("Pixel number along X", float) = 500
        _PixelNumberY ("Pixel number along X", float) = 500
    }

    SubShader {
        Pass {
            Tags { "RenderType"="Opaque" }

            CGPROGRAM
            #pragma vertex vert
            #pragma fragment frag
            #include "UnityCG.cginc"

            sampler2D _MainTex;
            float _PixelNumberX;
            float _PixelNumberY;

            struct v2f {
                half4 pos : POSITION;
                half2 uv : TEXCOORD0;
            };

            float4 _MainTex_ST;

            v2f vert(appdata_base v) {
                v2f o;
                o.pos = mul(UNITY_MATRIX_MVP, v.vertex);
                o.uv = TRANSFORM_TEX(v.texcoord, _MainTex);
                return o;
            }

            half4 frag(v2f i) : COLOR {
                half ratioX = 1 / _PixelNumberX;
                half ratioY = 1 / _PixelNumberY;
                half2 uv = half2((int)(i.uv.x / ratioX) * ratioX, (int)(i.uv.y / ratioY) * ratioY);
                return tex2D(_MainTex, uv);
            }

            ENDCG
        }
    }
    FallBack "Diffuse"
}