【Shader】用 Shader 画圆

Shader "Custom/SimpleCircleShader" {    Properties {        _Parameters ("Circle Parameters" , Vector) = (0.5, 0.5, 60, 0)        _CircleColor ("Circle Color", Color) = (0, 1, 1, 1)        _BackgroundColor("Background Color", Color) = (1,1,1,1)    }    CGINCLUDE    #include "UnityCG.cginc"    #include "ShaderToyDefines.cginc"    #pragma target 3.0    float4 _Parameters;    float4 _CircleColor;    float4 _BackgroundColor;    struct v2f {        float4 pos : SV_POSITION;        float4 scrPos : TEXCOORD0;    };    v2f vert(appdata_base v) {        v2f o;        o.pos = UnityObjectToClipPos (v.vertex);        o.scrPos = ComputeScreenPos(o.pos);        return o;    }    vec4 main(vec2 fragCoord);    fixed4 frag(v2f _iParam) : COLOR0 {        return main(gl_FragCoord);    }    vec4 circle(vec2 pos, vec2 center, float radius, float3 color, float antialias) {        float d = length(pos - center) - radius;        float t  = smoothstep(0, antialias, d);        return vec4(color, 1.0 - t);    }    vec4 main(vec2 fragCoord) {        vec2 pos = fragCoord;        vec4 layer1 = vec4(_BackgroundColor.rgb, 1.0);        vec4 layer2 = circle(pos, _Parameters.xy * iResolution.xy, _Parameters.z, _CircleColor.rgb, _Parameters.w);        return mix(layer1, layer2, layer2.a);    }    ENDCG    SubShader {        Pass {            CGPROGRAM            #pragma vertex vert            #pragma fragment frag            #pragma fragmentoption ARB_precision_hint_fastest            ENDCG        }    }    FallBack Off}

头文件：

/* ------------------------ Shader Toy 着色器输入 -----------------------------------uniform vec3      iResolution;           // viewport resolution (in pixels)uniform float     iGlobalTime;           // shader playback time (in seconds)uniform float     iTimeDelta;            // render time (in seconds)uniform int       iFrame;                // shader playback frameuniform float     iChannelTime[4];       // channel playback time (in seconds)uniform vec3      iChannelResolution[4]; // channel resolution (in pixels)uniform vec4      iMouse;                // mouse pixel coords. xy: current (if MLB down), zw: clickuniform samplerXX iChannel0..3;          // input channel. XX = 2D/Cubeuniform vec4      iDate;                 // (year, month, day, time in seconds)uniform float     iSampleRate;           // sound sample rate (i.e., 44100)-------------------------------------------------------------------------------------*/// 定义一系列宏和 Shader Toy 中的 GLSL 衔接#define vec2 float2#define vec3 float3#define vec4 float4#define mat2 float2x2#define mat3 float3x3#define mat4 float4x4#define iGlobalTime _Time.y#define mod fmod#define mix lerp#define fract frac#define texture2D tex2D#define iResolution _ScreenParams#define gl_FragCoord ((_iParam.scrPos.xy / _iParam.scrPos.w) * _ScreenParams.xy)#define PI2 6.28318530718#define pi 3.14159265358979#define halfpi (pi * 0.5)#define oneoverpi (1.0 / pi)

效果图：