I'm using a distortion shader to create a lens effect. The only problem I have is that it distorts everything above and below it. Is there a way to only distort below and not above? Here is the lens normal map: Code (CSharp): // Per pixel bumped refraction. // Uses a normal map to distort the image behind, and // an additional texture to tint the color. Shader "Distortion" { Properties { _BumpAmt ("Distortion", range (0,128)) = 10 _MainTex ("Tint Color (RGB)", 2D) = "white" {} _BumpMap ("Normalmap", 2D) = "bump" {} } CGINCLUDE #pragma fragmentoption ARB_precision_hint_fastest #pragma fragmentoption ARB_fog_exp2 #include "UnityCG.cginc" sampler2D _GrabTexture : register(s0); float4 _GrabTexture_TexelSize; sampler2D _BumpMap : register(s1); sampler2D _MainTex : register(s2); struct v2f { float4 vertex : POSITION; float4 uvgrab : TEXCOORD0; float2 uvbump : TEXCOORD1; float2 uvmain : TEXCOORD2; }; uniform float _BumpAmt; 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, i.uvgrab.xyw ); half4 tint = tex2D( _MainTex, i.uvmain ); return col * tint; } ENDCG Category { // We must be transparent, so other objects are drawn before this one. Tags { "Queue"="Transparent" "RenderType"="Opaque" } SubShader { // This pass grabs the screen behind the object into a texture. // We can access the result in the next pass as _GrabTexture GrabPass { Name "BASE" Tags { "LightMode" = "Always" } } // Main pass: Take the texture grabbed above and use the bumpmap to perturb it // on to the screen Pass { Name "BASE" Tags { "LightMode" = "Always" } CGPROGRAM #pragma vertex vert #pragma fragment frag struct appdata_t { float4 vertex : POSITION; float2 texcoord: TEXCOORD0; }; v2f vert (appdata_t v) { v2f o; o.vertex = mul(UNITY_MATRIX_MVP, 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 = MultiplyUV( UNITY_MATRIX_TEXTURE1, v.texcoord ); o.uvmain = MultiplyUV( UNITY_MATRIX_TEXTURE2, v.texcoord ); return o; } ENDCG } } // ------------------------------------------------------------------ // Fallback for older cards and Unity non-Pro SubShader { Blend DstColor Zero Pass { Name "BASE" SetTexture [_MainTex] { combine texture } } } } }
Well, minutes after posting this, I found out that I have a sprite with a layer order that was making it render before the lens and get the distortion. So nevermind then, but here is a lens distortion and normal map if anyone needs it lol
DanSuperGP, it works in Unity 5, the fix is pretty simply: replace Code (csharp): tex2Dproj( _GrabTexture, uvgrab.xyw); with Code (csharp): tex2Dproj( _GrabTexture, uvgrab.xyww);