Shader "Custom/ShaderFX" {

    Properties

    {

        _MainColor("MainColor", Color) = (1,1,1,1)

        _MainTex("Texture", 2D) = "white" {}

        _Fresnel("Fresnel Intensity", Range(0,200)) = 3.0

        _FresnelWidth("Fresnel Width", Range(0,2)) = 3.0

        _Distort("Distort", Range(0, 100)) = 1.0

        _IntersectionThreshold("Highlight of intersection threshold", range(0,1)) = .1 //Max difference for intersections

        _ScrollSpeedU("Scroll U Speed",float) = 2

        _ScrollSpeedV("Scroll V Speed",float) = 0

    }

        SubShader

        {

            Tags{ "Queue" = "Overlay" "IgnoreProjector" = "True" "RenderType" = "Transparent" }

            GrabPass{ "_GrabTexture" }

            Pass

            {

                Lighting Off ZWrite On

                Blend SrcAlpha OneMinusSrcAlpha

                Cull Off

                CGPROGRAM

                #pragma vertex vert

                #pragma fragment frag

                #include "UnityCG.cginc"

                struct appdata

                {

                    fixed4 vertex : POSITION;

                    fixed4 normal : NORMAL;

                    fixed3 uv : TEXCOORD0;

                };

                struct v2f

                {

                    fixed2 uv : TEXCOORD0;

                    fixed4 vertex : SV_POSITION;

                    fixed3 rimColor : TEXCOORD1;

                    fixed4 screenPos : TEXCOORD2;

                };

                sampler2D _MainTex, _CameraDepthTexture, _GrabTexture;

                fixed4 _MainTex_ST,_MainColor,_GrabTexture_ST, _GrabTexture_TexelSize;

                fixed _Fresnel, _FresnelWidth, _Distort, _IntersectionThreshold, _ScrollSpeedU, _ScrollSpeedV;

                v2f vert(appdata v)

                {

                    v2f o;

                    o.vertex = UnityObjectToClipPos(v.vertex);

                    o.uv = TRANSFORM_TEX(v.uv, _MainTex);

                    //scroll uv

                    o.uv.x += _Time * _ScrollSpeedU;

                    o.uv.y += _Time * _ScrollSpeedV;

                    //fresnel 

                    fixed3 viewDir = normalize(ObjSpaceViewDir(v.vertex));

                    fixed dotProduct = 1 - saturate(dot(v.normal, viewDir));

                    o.rimColor = smoothstep(1 - _FresnelWidth, 1.0, dotProduct) * .5f;

                    o.screenPos = ComputeScreenPos(o.vertex);

                    COMPUTE_EYEDEPTH(o.screenPos.z);//eye space depth of the vertex 

                    return o;

                }

                            fixed4 frag(v2f i,fixed face : VFACE) : SV_Target

                {

                                //intersection

                                fixed intersect = saturate((abs(LinearEyeDepth(tex2Dproj(_CameraDepthTexture,i.screenPos).r) - i.screenPos.z)) / _IntersectionThreshold);

                                fixed3 main = tex2D(_MainTex, i.uv);

                                //distortion

                                i.screenPos.xy += (main.rg * 2 - 1) * _Distort * _GrabTexture_TexelSize.xy;

                                fixed3 distortColor = tex2Dproj(_GrabTexture, i.screenPos);

                                distortColor *= _MainColor * _MainColor.a + 1;

                                //intersect hightlight

                                i.rimColor *= intersect * clamp(0,1,face);

                                main *= _MainColor * pow(_Fresnel,i.rimColor);

                                //lerp distort color & fresnel color

                main = lerp(distortColor, main, i.rimColor.r);

                main += (1 - intersect) * (face > 0 ? .03 : .3) * _MainColor * _Fresnel;

                return fixed4(main,.9);

            }

            ENDCG

        }

        }

}