GLSL CG Shader

Shader "Custom/Stars" {
Properties {
			iterations("_iterations", float) = 17
			formuparam("formuparam", float) = 0.53

			volsteps("volsteps",float) = 20
			stepsize("stepsize", float) = 0.1

			zoom("zoom", float) = 0.800
			tile("tile", float) = 0.850
			speed("speed", float) = 0.010

			brightness("brightness", float) = 0.00015
			darkmatter("darkmatter", float) = 0.30
			distfading("distfading", float) = 0.70
			saturation("saturation", float) = 0.80
			mouse("mouse",Vector) = (0., 0., 0., 0.)
			resolution("resolution",Vector) = (1280, 720, 0., 0.)
    }
    SubShader {
        Pass {
            CGPROGRAM

            #pragma vertex vert
            #pragma fragment frag

            #include "UnityCG.cginc"


            // uniforms corresponding to properties
			uniform float iterations;
			uniform float formuparam;

			uniform float volsteps;
			uniform float stepsize;

			uniform float zoom;
			uniform float tile;
			uniform float speed;

			uniform float brightness;
			uniform float darkmatter;
			uniform float distfading;
			uniform float saturation;
			uniform float2 mouse;
			uniform float2 resolution;

            float4 vert(appdata_base v) : POSITION {
                return mul (UNITY_MATRIX_MVP, v.vertex);
            }


            float4 frag(float4 sp:WPOS) : COLOR {
                //get coords and direction
				float2  uv = sp.xy/resolution.xy-.5;
				uv.y*=resolution.y/resolution.x;
				float3 dir = float3(uv*zoom,1.);
				float time=_Time*speed+.25;

				//mouse rotation
				float a1=.5+mouse.x/resolution.x*2.;
				float a2=.8+mouse.y/resolution.y*2.;
				float2x2 rot1 = float2x2(cos(a1),sin(a1),-sin(a1),cos(a1));
				float2x2 rot2 = float2x2(cos(a2),sin(a2),-sin(a2),cos(a2));
				dir.xz=mul(rot1, dir.xz);
				dir.xy=mul(rot2, dir.xy);
				float3 from=float3(1.,.5,0.5);
				from+=float3(time*2.,time,-2.);
				from.xz=mul(rot1,from.xz);
				from.xy=mul(rot2,from.xy);

				//volumetric rendering
				float s=0.1,fade=1.;
				float3 v=float3(0,0,0);
				for (int r=0; r<volsteps; r++) {
					float3 p=from+s*dir*.5;
					p = abs(float3(tile,0, 0)-fmod(p,float3(tile*2,0,0))); // tiling fold
					float pa,a=pa=0.;
					for (int i=0; i<iterations; i++) {
						p=abs(p)/dot(p,p)-formuparam; // the magic formula
						a+=abs(length(p)-pa); // absolute sum of average change
						pa=length(p);
					}
					float dm=max(0.,darkmatter-a*a*.001); //dark matter
					a*=a*a; // add contrast
					if (r>6) fade*=1.-dm; // dark matter, don't render near
					//v+=vec3(dm,dm*.5,0.);
					v+=fade;
					v+=float3(s,s*s,s*s*s*s)*a*brightness*fade; // coloring based on distance
					fade*=distfading; // distance fading
					s+=stepsize;
				}
				v= v * saturation + length(v) * (1.0 - saturation);//mix(float3(length(v)),v,saturation); //color adjust
				return float4(v*.01,1.);