137 lines
4.4 KiB
Plaintext
137 lines
4.4 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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_Speed("Speed", range(0, 1)) = 0.1
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_Symmetry("Symmetry", range(0, 1)) = 0
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_EscapeRadius("EscapeRadius", range(2, 200)) = 50
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_SpectrumTexture("SpectrumTexture", 2D) = "white" {}
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_ThemeTexture("ThemeTexture", 2D) = "white" {}
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_SpectrumSize("SpectrumSize", float) = 16
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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 _Speed;
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float _Symmetry;
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float _EscapeRadius;
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int _MaxIter;
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sampler2D _MainTex;
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sampler2D _SpectrumTexture;
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sampler2D _ThemeTexture;
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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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{
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float2 uv = i.uv - 0.5;
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uv = abs(uv);
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uv = lerp(i.uv - 0.5, uv, _Symmetry);
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float2 c = _Area.xy + uv * _Area.zw;
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c = rot(c, _Area.xy, _Angle);
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// cool modulation
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float time = _Time.y;
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float sub = tex2D(_SpectrumTexture, 0.0);
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float bass = tex2D(_SpectrumTexture, 0.25);
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float mids = tex2D(_SpectrumTexture, 0.50);
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float highs = tex2D(_SpectrumTexture, 0.75);
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float r = lerp(2.0, 200, bass);
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// float maxIterations = lerp(2.0, 500, sub);
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// float maxIterations = lerp(2.0, 500, sub);
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// float speed = sub * -scale;
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float maxIterations = _MaxIter;
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// float r = _EscapeRadius;
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float speed = _Speed;
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float2 z; // track pixel jumping across screen
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float2 zPrev;
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float r2 = r*r;
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float iter; // track current iteration
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for (iter = 0; iter < _MaxIter; iter++) {
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// update z based on previous z value and add original starting position
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// zPrev = z;
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float rotation = sin(time);
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zPrev = rot(z, 0, rotation);
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z = float2(z.x*z.x-z.y*z.y, 2*z.x*z.y) + c;
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if (dot(z, zPrev) > r2) {
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break;
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}
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}
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if (iter >= _MaxIter) {
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return 0;
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}
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float val = iter / float(_MaxIter);
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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 = tex2D(_ThemeTexture, abs(sin(time)));
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// float4 col = tex2D(_ThemeTexture, val + abs(time);
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col *= smoothstep(3, 0, fracIter);
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// dark bands
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float angle = atan2(z.x, z.y);
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col *= 1 + sin(angle*2 + mids*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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