113 lines
3.5 KiB
Plaintext
113 lines
3.5 KiB
Plaintext
Shader "Explorer/Mandelbrot"
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{
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Properties
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{
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_MainTex ("Texture", 2D) = "white" {}
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// first two numbers are center of area, second two - size of area
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_Area("Area", vector) = (0, 0, 4 ,4)
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_Angle("Angle", range(-3.1415, 3.1415)) = 0
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_MaxIter("Max Iterations", range(0, 555)) = 255
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_Color("Color", range(0,1)) = 0.5
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_Repeat("Repeat", float) = 1
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_Speed("Speed", range(0, 1)) = 0.1
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_Colors("Colors", vector) = (3.0, 4.0, 5.0, 0.0)
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}
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SubShader
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{
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// No culling or depth
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Cull Off ZWrite Off ZTest Always
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Pass
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{
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CGPROGRAM
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#pragma vertex vert
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#pragma fragment frag
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#include "UnityCG.cginc"
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struct appdata
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{
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float4 vertex : POSITION;
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float2 uv : TEXCOORD0;
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};
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struct v2f
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{
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float2 uv : TEXCOORD0;
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float4 vertex : SV_POSITION;
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};
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v2f vert (appdata v)
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{
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v2f o;
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o.vertex = UnityObjectToClipPos(v.vertex);
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o.uv = v.uv;
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return o;
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}
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float4 _Area;
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float _Angle;
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float _Color;
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float3 _Colors;
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float _Repeat;
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float _Speed;
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int _MaxIter;
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sampler2D _MainTex;
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float2 rot(float2 p, float2 pivot, float a) {
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float s = sin(a);
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float c = cos(a);
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p -= pivot;
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p = float2(p.x*c-p.y*s, p.x*s+p.y*c);
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p += pivot;
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return p;
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}
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fixed4 frag (v2f i) : SV_Target {
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float2 uv = i.uv - 0.5;
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float2 offset = _Area.xy + uv * _Area.zw;
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float2 z; // track pixel jumping across screen
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float2 zPrev;
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float r = 20; // escape radius
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float r2 = r*r;
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float vxsquare = 0;
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float vysquare = 0;
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float iteration = 0;
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float lastIteration = _MaxIter;
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do {
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vxsquare = uv.x * uv.x;
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vysquare = uv.y * uv.y;
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uv = float2(vxsquare - vysquare, uv.x * uv.y * 2) + offset;
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iteration++;
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if ((lastIteration == _MaxIter) && (vxsquare + vysquare) > 4.0) {
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lastIteration = iteration + 1;
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}
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} while (iteration < lastIteration);
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float val = (float(iteration) - (log(log(sqrt(vxsquare + vysquare))) / log(2.0))) / float(_MaxIter);
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return float4(sin(val * _Colors.x), sin(val * _Colors.y), sin(val * _Colors.z), 1);
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// float dist = length(z); // distance from origin
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// float fracIter = (dist - r) / (r2 - r); // linear interpolation
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// fracIter = log2(log(dist) / log(r) ); // double exponential interpolation
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// iter -= fracIter;
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// float m = sqrt(iter / _MaxIter);
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// float4 col = sin(float4(.3, .45, .65, 1) * m * 20)*.5 + .5; // procedural colors
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// col = tex2D(_MainTex, float2(m * _Repeat + _Time.y*_Speed, _Color));
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// col *= smoothstep(3, 0, fracIter);
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// float angle = atan2(z.x, z.y);
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// col *= 1 + sin(angle*2 + _Time.y*4)*.2;
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// return col;
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}
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ENDCG
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}
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}
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}
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