5 Aug 2018

X-Ray Effect in Shader

In many games, we can use special ability to see through the wall. So In this post I am going to make a X-ray effect.

A X-Ray is easy to achieve. basicly, just need to add an additional Pass{} in shader which the ZTest should set to Greater, and the ZWrite should close.

This is the result of the experiment:

Code:

Shader "MyShader/Transparent2"
{
	Properties
	{
		_MainTex("MainTex",2D) = ""{}
		_Color("Color", Color) = (1,1,1,1)
		_OccPower("Occlusion Power", Range(0,2)) = 0.5
		_OccColor("Occlusion Color", Color) = (1,1,1,1)
	}
		SubShader
		{
			Tags{"RenderTyoe" = "Transparent" "Queue" = "Transparent"}

			Pass //  This pass is for X-ray
			{
				Blend DstAlpha One

				// When the Z value of the object's pixel is greater 
				//than the Z value of the current camera on the pixel, it will pass Ztest
				ZTest Greater

				ZWrite Off
				CGPROGRAM
				#pragma vertex vert
				#pragma fragment frag

				#include "UnityCG.cginc"

				float _OccPower;
				fixed4 _OccColor;

				struct appdata
				{
					float4 vertex : POSITION;
					float3 normal : NORMAL;

				};

				struct v2f
				{
					float3 worldNormal : TEXCOORD0;
					float4 pos : SV_POSITION;
					float4 worldVertex : TEXCOORD1;
				};



				v2f vert(appdata v)
				{
					v2f o;
					o.pos = UnityObjectToClipPos(v.vertex);
					o.worldNormal = normalize(mul(v.normal,unity_WorldToObject));
					o.worldVertex = normalize(mul(unity_ObjectToWorld, v.vertex));

					return o;
				}

				fixed4 frag(v2f i) : SV_Target
				{

					float3 viewDir = normalize(_WorldSpaceCameraPos.xyz - i.worldVertex.xyz);

					// rim effect
					float rim = 1 - saturate(dot(i.worldNormal,viewDir));

					fixed3 col = pow(rim, _OccPower) * _OccColor.rgb;

					return fixed4(col,0.5f);
				}
				ENDCG
			}



			Pass // This pass is for the model itself
			{
				Blend SrcAlpha OneMinusSrcAlpha
				ZWrite On
				ZTest LEqual
				CGPROGRAM
				#pragma vertex vert
				#pragma fragment frag

				#include "UnityCG.cginc"

				struct appdata
				{
					float4 vertex : POSITION;
					float2 uv : TEXCOORD0;
				};

				struct v2f
				{
					float2 uv : TEXCOORD0;
					float4 vertex : SV_POSITION;
				};

				sampler2D _MainTex;
				float4 _MainTex_ST;
				fixed4 _Color;

				v2f vert(appdata v)
				{
					v2f o;
					o.vertex = UnityObjectToClipPos(v.vertex);
					o.uv = TRANSFORM_TEX(v.uv, _MainTex);
					return o;
				}

				fixed4 frag(v2f i) : SV_Target
				{
					// sample the texture
					fixed3 col = tex2D(_MainTex, i.uv).rgb * _Color.rgb;

					return fixed4(col,1);
				}
				ENDCG
			}
		}
}

End –Cheng Gu

X-Ray Effect in Shader

Tags: