refraction ..... any master give me some hiints

Unity Engine
1

I want to write kindof shader that has refractive effects,twisting the objs’ image behind it…How???

2

You need Unity Pro and to use the GrabPass function.

This should do what you’re after, using a normal map as the distortion.

		GrabPass {
			Name "DistortionGrab"
		}

		Pass
		{
			Name "Distortion"
			Blend Off
			CGPROGRAM
				#pragma vertex vert
				#pragma fragment frag
				#pragma fragmentoption ARB_precision_hint_fastest
				#include "UnityCG.cginc"

				struct v2f {
					float4 pos		: POSITION;
					float4 uvgrab		: TEXCOORD0;
					float2 uv		: TEXCOORD1;
					float4 screenPos	: TEXCOORD2;
				};

				v2f vert (appdata_full v)
				{
					v2f o;
					o.pos = 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.pos.x, o.pos.y * scale) + o.pos.w) * 0.5;
					o.uvgrab.zw = o.pos.zw;
					o.uv = v.texcoord.xy;
					return o;
				}

				sampler2D _BumpMap;
				sampler2D _GrabTexture;
				float4 _GrabTexture_TexelSize;

				half4 frag( v2f i ) : COLOR
				{
					riverUVs.y += 0.3 + _Time * _WaterSpeed2;
					float3 normal = UnpackNormal(tex2D(_BumpMap, i.uv));
				
					float2 offset = normal.xy * 5 * _GrabTexture_TexelSize.xy;
					i.uvgrab.xy = (offset * i.uvgrab.z) + i.uvgrab.xy;
					return half4(tex2Dproj(_GrabTexture, UNITY_PROJ_COORD(i.uvgrab)).rgb, 1);
				}
			ENDCG
		}
3

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