﻿// Upgrade NOTE: replaced 'mul(UNITY_MATRIX_MVP,*)' with 'UnityObjectToClipPos(*)'

Shader "Custom/SimpleGrabPassBlur" {
	Properties{
		_Color("Main Color", Color) = (1,1,1,1)
		_BumpAmt("Distortion", Range(0,128)) = 10
		_MainTex("Tint Color (RGB)", 2D) = "white" {}
		_BumpMap("Normalmap", 2D) = "bump" {}
		_Size("Size", Range(0, 20)) = 1
	}

		Category{

			// We must be transparent, so other objects are drawn before this one.
			Tags { "Queue" = "Transparent" "IgnoreProjector" = "True" "RenderType" = "Opaque" }


			SubShader {

			// Horizontal blur
			GrabPass {
				Tags { "LightMode" = "Always" }
			}
			Pass {
				Tags { "LightMode" = "Always" }

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

				struct appdata_t {
					float4 vertex : POSITION;
					float2 texcoord: TEXCOORD0;
				};

				struct v2f {
					float4 vertex : POSITION;
					float4 uvgrab : TEXCOORD0;
				};

				v2f vert(appdata_t v) {
					v2f o;
					o.vertex = UnityObjectToClipPos(v.vertex);
					#if UNITY_UV_STARTS_AT_TOP
					float scale = -1.0;
					#else
					float scale = 1.0;
					#endif
					o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y * scale) + o.vertex.w) * 0.5;
					o.uvgrab.zw = o.vertex.zw;
					return o;
				}

				sampler2D _GrabTexture;
				float4 _GrabTexture_TexelSize;
				float _Size;

				half4 frag(v2f i) : COLOR {
					//                  half4 col = tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(i.uvgrab));
					//                  return col;

										half4 sum = half4(0,0,0,0);
										#define GRABPIXEL(weight,kernelx) tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x + _GrabTexture_TexelSize.x * kernelx*_Size, i.uvgrab.y, i.uvgrab.z, i.uvgrab.w))) * weight
										sum += GRABPIXEL(0.05, -4.0);
										sum += GRABPIXEL(0.09, -3.0);
										sum += GRABPIXEL(0.12, -2.0);
										sum += GRABPIXEL(0.15, -1.0);
										sum += GRABPIXEL(0.18,  0.0);
										sum += GRABPIXEL(0.15, +1.0);
										sum += GRABPIXEL(0.12, +2.0);
										sum += GRABPIXEL(0.09, +3.0);
										sum += GRABPIXEL(0.05, +4.0);

										return sum;
									}
									ENDCG
								}
			// Vertical blur
			GrabPass {
				Tags { "LightMode" = "Always" }
			}
			Pass {
				Tags { "LightMode" = "Always" }

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

				struct appdata_t {
					float4 vertex : POSITION;
					float2 texcoord: TEXCOORD0;
				};

				struct v2f {
					float4 vertex : POSITION;
					float4 uvgrab : TEXCOORD0;
				};

				v2f vert(appdata_t v) {
					v2f o;
					o.vertex = UnityObjectToClipPos(v.vertex);
					#if UNITY_UV_STARTS_AT_TOP
					float scale = -1.0;
					#else
					float scale = 1.0;
					#endif
					o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y * scale) + o.vertex.w) * 0.5;
					o.uvgrab.zw = o.vertex.zw;
					return o;
				}

				sampler2D _GrabTexture;
				float4 _GrabTexture_TexelSize;
				float _Size;

				half4 frag(v2f i) : COLOR {
					//                  half4 col = tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(i.uvgrab));
					//                  return col;

										half4 sum = half4(0,0,0,0);
										#define GRABPIXEL(weight,kernely) tex2Dproj( _GrabTexture, UNITY_PROJ_COORD(float4(i.uvgrab.x, i.uvgrab.y + _GrabTexture_TexelSize.y * kernely*_Size, i.uvgrab.z, i.uvgrab.w))) * weight
										//G(X) = (1/(sqrt(2*PI*deviation*deviation))) * exp(-(x*x / (2*deviation*deviation)))

										sum += GRABPIXEL(0.05, -4.0);
										sum += GRABPIXEL(0.09, -3.0);
										sum += GRABPIXEL(0.12, -2.0);
										sum += GRABPIXEL(0.15, -1.0);
										sum += GRABPIXEL(0.18,  0.0);
										sum += GRABPIXEL(0.15, +1.0);
										sum += GRABPIXEL(0.12, +2.0);
										sum += GRABPIXEL(0.09, +3.0);
										sum += GRABPIXEL(0.05, +4.0);

										return sum;
									}
									ENDCG
								}

										// Distortion
										GrabPass {
											Tags { "LightMode" = "Always" }
										}
										Pass {
											Tags { "LightMode" = "Always" }

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

											struct appdata_t {
												float4 vertex : POSITION;
												float2 texcoord: TEXCOORD0;
											};

											struct v2f {
												float4 vertex : POSITION;
												float4 uvgrab : TEXCOORD0;
												float2 uvbump : TEXCOORD1;
												float2 uvmain : TEXCOORD2;
											};

											float _BumpAmt;
											float4 _BumpMap_ST;
											float4 _MainTex_ST;

											v2f vert(appdata_t v) {
												v2f o;
												o.vertex = UnityObjectToClipPos(v.vertex);
												#if UNITY_UV_STARTS_AT_TOP
												float scale = -1.0;
												#else
												float scale = 1.0;
												#endif
												o.uvgrab.xy = (float2(o.vertex.x, o.vertex.y * scale) + o.vertex.w) * 0.5;
												o.uvgrab.zw = o.vertex.zw;
												o.uvbump = TRANSFORM_TEX(v.texcoord, _BumpMap);
												o.uvmain = TRANSFORM_TEX(v.texcoord, _MainTex);
												return o;
											}

											fixed4 _Color;
											sampler2D _GrabTexture;
											float4 _GrabTexture_TexelSize;
											sampler2D _BumpMap;
											sampler2D _MainTex;

											half4 frag(v2f i) : COLOR {
												// calculate perturbed coordinates
												half2 bump = UnpackNormal(tex2D(_BumpMap, i.uvbump)).rg; // we could optimize this by just reading the x  y without reconstructing the Z
												float2 offset = bump * _BumpAmt * _GrabTexture_TexelSize.xy;
												i.uvgrab.xy = offset * i.uvgrab.z + i.uvgrab.xy;

												half4 col = tex2Dproj(_GrabTexture, UNITY_PROJ_COORD(i.uvgrab));
												half4 tint = tex2D(_MainTex, i.uvmain) * _Color;

												return col * tint;
											}
											ENDCG
										}
									}
		}
}