Unity Shader相交算法實現簡易防能量盾

Unity Shader學習：相交算法實現簡易防能量盾
主要思路：對比物體和場景深度圖在觀察空間下的深度差值，深度差越小表示相交，顏色越深，在加上邊緣光勾出輪廓。
shader部分:
Shader "Unlit/DepthOutline" { Properties{ _MainTex("MainTex",2D) = "white"{} _RimFactor("RimFactor",Range(0.0,5.0))=1.0 _DistanceFactor("DistanceFactor",Range(0.0,10.0))=1.0 _RimColor("RimColor",Color)=(1,0,0,1) _DistanceFactor2("DistanceFactor2",Range(0.0,10.0))=1.0 _DistanceFactor3("DistanceFactor3",Range(0.0,5.0)) = 1.0 } SubShader{ Tags{"Queue" = "Transparent" "RenderType" = "Transparent" "IgnoreProjector"="true"} Pass{ Blend SrcAlpha OneMinusSrcAlpha ZWrite Off Cull Off CGPROGRAM #include "UnityCG.cginc" #pragma vertex vert #pragma fragment frag sampler2D _MainTex; float4 _MainTex_ST; sampler2D _CameraDepthTexture; float _RimFactor; float _DistanceFactor; float4 _RimColor; float _DistanceFactor2; float _DistanceFactor3; struct a2v { float4 vertex:POSITION; float2 uv:TEXCOORD0; float3 normal:NORMAL; }; struct v2f { float2 uv:TEXCOORD0; float4 pos:SV_POSITION; float4 screenPos:TEXCOORD1; float3 worldNormal:TEXCOORD2; float3 worldViewDir:TEXCOORD3; }; v2f vert(a2v v) { v2f o; o.pos = UnityObjectToClipPos(v.vertex); //ComputeScreenPos函數，得到歸一化前的視口座標xy //z分量為裁剪空間的z值，範圍[-Near,Far] o.screenPos = ComputeScreenPos(o.pos); o.uv = TRANSFORM_TEX(v.uv,_MainTex); //COMPUTE_EYEDEPTH函數，將z分量範圍[-Near,Far]轉換為[Near,Far] COMPUTE_EYEDEPTH(o.screenPos.z); o.worldNormal = UnityObjectToWorldNormal(v.normal); o.worldViewDir = WorldSpaceViewDir(v.vertex).xyz; return o; } float4 frag(v2f i):SV_Target { float3 mainTex = 1-tex2D(_MainTex,i.uv).xyz; //獲取深度紋理,通過LinearEyeDepth函數將採樣的深度紋理值轉換為對應的深度範圍[Near~Far] float sceneZ = LinearEyeDepth(SAMPLE_DEPTH_TEXTURE_PROJ(_CameraDepthTexture,UNITY_PROJ_COORD(i.screenPos))); //觀察空間深度差,值越小顏色值越大 float distance =1 - saturate(sceneZ - i.screenPos.z); //消除內部深度變化較大時產生的鋸齒 if (distance>0.999999) { distance = 0; } //調整深度差值的變化曲線 distance = pow(saturate(_DistanceFactor * log(distance) + _DistanceFactor3), _DistanceFactor2); //角度越大邊緣光越亮 float rim =1 - abs(dot(normalize(i.worldNormal), normalize(i.worldViewDir))); rim = pow(rim, _RimFactor); float4 col = float4(0,0,0,0); col = lerp(col, float4(_RimColor.rgb,0.3), mainTex.r); //根據邊緣光以及深度差漸變 col = float4(_RimColor.rgb,lerp(col.a,_RimColor.a, distance)); col = lerp(col, _RimColor, rim); return col; } ENDCG } } }