port from perforce

underwater4k/tex1.glsl_2

@@ -0,0 +1,81 @@
+// Parameters from our host
+// x: #sceneid.#scenetime (float)
+// y: undefined
+// z: Snare drum intensity (amiga ball radius gain)
+// w: undefined
+uniform vec4 Z; 
+
+float rnd(vec2 p)
+{
+	p.x += p.y * 57.;
+	return sin(cos(p.x) * p.x);
+}
+
+float scale;
+vec2 hash( vec2 p )
+{
+	p = mod(p, scale);
+	p = vec2( dot(p,vec2(127.1,311.7)),
+			  dot(p,vec2(269.5,183.3)) );
+
+	return -1.0 + 2.0*fract(sin(p)*43758.5453123);
+}
+
+float noise( in vec2 p, float s )
+{
+	scale = s;
+	p *= s;
+    vec2 i = floor( p );
+    vec2 f = fract( p );
+	
+	vec2 u = f*f*(3.0-2.0*f);
+
+    return mix( mix( dot( hash( i + vec2(0.0,0.0) ), f - vec2(0.0,0.0) ), 
+                     dot( hash( i + vec2(1.0,0.0) ), f - vec2(1.0,0.0) ), u.x),
+                mix( dot( hash( i + vec2(0.0,1.0) ), f - vec2(0.0,1.0) ), 
+                     dot( hash( i + vec2(1.0,1.0) ), f - vec2(1.0,1.0) ), u.x), u.y);
+}
+
+float voronoi(vec2 p)
+{
+	p = mod(p, 1.0);
+	float min1 = 1, min2 = 1; float seed = 10; const int numPoints = 256;
+	for (int i = 0; i < numPoints; ++i)
+	{
+		vec2 pointPos = vec2(rnd(vec2(0, seed++)), rnd(vec2(1, seed++)))*.5+.5;
+		//pointPos += vec2(sin(Z.z+rnd(vec2(0, seed++))), cos(Z.z+rnd(vec2(1, seed++))))*0.1;
+		vec2 d = abs(p - pointPos);
+		vec2 s = step(0.5, d);
+		d = s+d*(-s*2+1);
+		float dist = length(d);
+		if (dist < min2)
+		{
+			if (dist < min1)
+			{
+				min2 = min1;
+				min1 = dist;
+			}
+			else
+			{
+				min2 = dist;
+			}
+		}
+	}
+
+	//return pow(1.0 - (min2 - min1), 32.0);
+	return 1.0 - min1 * 10.0;//(min2 - min1) * 8.0;
+}
+
+void main()
+{
+	vec2 p = gl_FragCoord.xy / Z.xy;
+	float l = voronoi(p);
+	
+	float f = 0.5;
+	float seed = 10.0;
+	for (float t = 2.0; t <= Z.x; t *= 2.0)
+	{
+		f += (0.5 / pow(t, 0.8)) * noise(p,t);
+	}
+	gl_FragColor = vec4(l,f,l,1);
+}