Shader剔除像素绘制扇形
Shader "Custom/Indicator" { Properties { _MainTex("Main Texture", 2D) = "white" {} _Color ("Color", Color) = (0.17,0.36,0.81,0.0) _Angle ("Angle", Range(0, 360)) = 60 _Gradient ("Gradient", Range(0, 1)) = 0 } SubShader { Tags { "Queue"="Transparent" "RenderType"="Transparent" "IgnoreProjector"="True" } Pass { ZWrite Off Blend SrcAlpha OneMinusSrcAlpha CGPROGRAM #pragma vertex vert #pragma fragment frag #include "UnityCG.cginc" sampler2D _MainTex; float4 _Color; float _Angle; float _Gradient; struct fragmentInput { float4 pos : SV_POSITION; float2 uv : TEXTCOORD0; }; fragmentInput vert (appdata_base v) { fragmentInput o; o.pos = mul (UNITY_MATRIX_MVP, v.vertex); o.uv = v.texcoord.xy; return o; } fixed4 frag(fragmentInput i) : SV_Target { // 离中心点的距离 float distance = sqrt(pow(i.uv.x - 0.5, 2) + pow(i.uv.y - 0.5, 2)); // 在圆外 if(distance > 0.5f){ discard; } // 根据距离计算透明度渐变 float grediant = (1 - distance - 0.5 * _Gradient) / 0.5; // 正常显示的结果 fixed4 result = tex2D(_MainTex, i.uv) * _Color * fixed4(1,1,1, grediant); float x = i.uv.x; float y = i.uv.y; float deg2rad = 0.017453; // 角度转弧度 // 根据角度剔除掉不需要显示的部分 // 大于180度 if(_Angle > 180){ if(y > 0.5 && abs(0.5 - y) >= abs(0.5 - x) / tan((180 - _Angle / 2) * deg2rad)) discard;// 剔除 } else // 180度以内 { if(y > 0.5 || abs(0.5 -y) < abs(0.5 - x) / tan(_Angle / 2 * deg2rad)) discard; } return result; } ENDCG } } FallBack "Diffuse" }
转自:http://baizihan.me/2016/10/draw-sector/