Doprez · May 27, 2025 14:37 · May 27, 2025 · May 27, 2025
diff --git a/OilStainPortal.sdsl b/OilStainPortal.sdsl
@@ -1,6 +1,6 @@
 // https://www.shadertoy.com/view/ll2GRt
 
-shader OilStainPortal<float Frequency, float Amplitude, float Speed> : ComputeColor, Texturing
+shader OilStainPortal : ComputeColor, Texturing
 {
     override float4 Compute()
     {

diff --git a/OilStainPortal.sdsl b/OilStainPortal.sdsl
@@ -0,0 +1,114 @@
+// https://www.shadertoy.com/view/ll2GRt
+
+shader OilStainPortal<float Frequency, float Amplitude, float Speed> : ComputeColor, Texturing
+{
+    override float4 Compute()
+    {
+	    float2 uv = 1.0 - 2.0 * (streams.TexCoord);
+        float t = Global.Time * 0.6;
+
+        float2 rv = uv/(length(uv*2.5)*(uv*90.0));
+        var rot1 = rot2d(0.5*t); // Rotates the texture
+        uv = mul(uv, rot1);
+        float val = 0.5*fbm(uv*2.0*fbmLow(length(uv)+rv-t));
+        var rot2 = rot2d(-0.*t);
+        uv = mul(uv, rot2);
+
+        var col1 = 0.5*fbm(uv*val*24.0)+0.01*r(uv.x,uv.y);
+
+        float4 fragColor = 1.6*float4( float3(col1,col1,col1), 1.0 );
+
+        fragColor.rgb *= 3.12;
+        fragColor.rgb = fragColor.rgb/(0.9+fragColor.rgb);
+        fragColor.rgb = smoothstep(0.001, 0.88, fragColor.rgb);
+        //fragColor.rgb = pow(fragColor.rgb, float3(1.0/2.2, 1.0/2.2, 1.0/2.2));
+
+        return fragColor;
+    }
+
+    float2x2 rot2d(float angle)
+    {
+        return float2x2(cos(angle),-sin(angle),sin(angle),cos(angle));
+    }
+
+    float r(float a, float b)
+    {
+        return frac(sin(dot(float2(a,b),float2(12.9898,78.233)))*43758.5453);
+    }
+
+    float h(float a)
+    {
+        return frac(sin(dot(a,dot(12.9898,78.233)))*43758.5453);
+    }
+
+    float noise(float3 x)
+    {
+        float3 p  = floor(x);
+        float3 f  = frac(x);
+        f = f*f*(3.0-2.0*f);
+        float n = p.x + p.y*57.0 + 113.0*p.z;
+        return lerp(lerp(lerp( h(n+0.0), h(n+1.0),f.x),
+                   lerp( h(n+57.0), h(n+58.0),f.x),f.y),
+               lerp(lerp( h(n+113.0), h(n+114.0),f.x),
+                   lerp( h(n+170.0), h(n+171.0),f.x),f.y),f.z);
+    }
+
+// https://iquilezles.org/articles/morenoise
+// http://www.pouet.net/topic.php?post=401468
+    float3 dnoise2f(float2 p)
+    {
+        float i = floor(p.x), j = floor(p.y);
+        float u = p.x-i, v = p.y-j;
+        float du = 30.*u*u*(u*(u-2.)+1.);
+        float dv = 30.*v*v*(v*(v-2.)+1.);
+        u=u*u*u*(u*(u*6.-15.)+10.);
+        v=v*v*v*(v*(v*6.-15.)+10.);
+        float a = r(i,     j    );
+        float b = r(i+1.0, j    );
+        float c = r(i,     j+1.0);
+        float d = r(i+1.0, j+1.0);
+        float k0 = a;
+        float k1 = b-a;
+        float k2 = c-a;
+        float k3 = a-b-c+d;
+        return float3(k0 + k1*u + k2*v + k3*u*v,
+                    du*(k1 + k3*v),
+                    dv*(k2 + k3*u));
+    }
+
+    float fbm(float2 uv)
+    {               
+        float2 p = uv;
+    	float f, dx, dz, w = 0.5;
+        f = dx = dz = 0.0;
+        for(int i = 0; i < 28; ++i)
+        {        
+            float3 n = dnoise2f(uv);
+            dx += n.y;
+            dz += n.z;
+            f += w * n.x / (1.0 + dx*dx + dz*dz);
+            w *= 0.86;
+            uv *= float2(1.16, 1.16);
+            var rotation = rot2d(1.25*noise(float3(p*0.1, 0.12*Global.Time))+
+                        0.75*noise(float3(p*0.1, 0.20*Global.Time)));
+            uv = mul(uv, rotation);
+        }
+        return f;
+    }
+
+    float fbmLow(float2 uv)
+    {
+        float f, dx, dz, w = 0.5;
+        f = dx = dz = 0.0;
+        for(int i = 0; i < 4; ++i)
+        {
+            float3 n = dnoise2f(uv);
+            dx += n.y;
+            dz += n.z;
+            f += w * n.x / (1.0 + dx*dx + dz*dz);
+            w *= 0.75;
+            uv *= float2(1.5, 1.5);
+        }
+        return f;
+    }
+};