mad fractal action

Assets/Scenes/GFLPC_Mandelbrot/MandelBrotHybrid.shader

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