#version 100


// Parameters from our host
// x: Scene
// y: Zeit
// z: Quadratzeit mit Faktor
// w: Aspect ratio
varying vec4 Y,Z;

// All data of our world
float j, k, g=acos(-1.0), h= sqrt( 0.75 );

vec2 r(vec2 v,float y)
{
	return cos(y)*v+sin(y)*vec2(-v.y,v.x);
}

//s around y axis w times
void s(inout vec2 v,float x, float y) 
{
	float z=mod(atan(v.y,v.x),y)-y*.5;
	v=(length(v))*vec2(cos(z),sin(z));
	v.x-=x;
}

//radius of the l/ radius of the ring
float l(vec3 p,float f) 
{
	return length(vec2(length(p.xz) - f,p.y));
}

float i( vec2 p, float y, float z )
{
    return length( max( abs(p) - vec2(y) + vec2(z), 0.0 ) ) - z;
}

float u( vec3 p )
{
	return fract( sin( p.x * 151.0 + p.y * 33.0 + p.z ) * 11.0 );
}

float w(vec3 p) 
{
	vec2 e = vec2(1.0, 0.0);
	vec3 o= smoothstep(0.0,1.0,fract( p ));
	p= floor( p );

	vec4 n= mix(
		vec4(
			u( p+e.yyy),//n000, 
			u( p+e.xyy),//n100, 
			u( p+e.yxy),//n010, 
			u( p+e.xxy)),//n110),
		vec4(
			u( p+e.yyx),//n001, 
			u( p+e.xyx),//n101, 
			u( p+e.yxx),//n011, 
			u( p+e.xxx)),//n111),
		o.z);
	e = mix(n.xy, n.zw, o.y);
	return mix(e.x, e.y, o.x);	
}


























































































/////////////////////////////////////////////////////////////////////////////////////////////////////////////
// Schlange im Tunnel
/////////////////////////////////////////////////////////////////////////////////////////////////////////////

float A(vec3 p)
{
	//p.z-= 5.5;
	vec3 o= p;
	p.z= mod( p.z, 11.0 ) - 5.5;
	o-= p;
	p.xy= r( p.xy, o.z + smoothstep( -0.2, 0.2, cos( j * 5.0 + cos( o.z * 33.0 ) ) ) );
	s( p.xy, 4.8, g/4.5 );
	return i( p.xz, 1.0, 0.3 );
}

float B(vec3 p)
{
	return 99.0;
}

float C(vec3 p)
{
	//p.z-= j * 33.0;
	p.z= mod( p.z, 7.0 ) - 3.5;
	s( p.xy, 0.0, g/4.0 );
	return max( abs( length( p.xy ) - 9.0 ) - 0.2, 3.0 - length( p.yz )  );
}

float D(vec3 p)
{
	p.z+= j * 33.0;
	p.xy= r( p.xy, p.z * 0.2 - j * 8.0 );
	p.x+= 1.0;
	float z= 3.5 * smoothstep( -22.0, 0.0, p.z ) - 3.0 + Y.z * 17.0;
	p.z= mod( p.z, 0.2 ) - 0.1;
	return l( p.xzy, z ) - 1.0;
}

float f(vec3 p)
{
	float z= min( min( A(p), B(p) ), C(p) );
	return max( length( p ) - 66.0, min( z, max( 0.5 - z, D(p) ) ) );
}









































void main()
{
	k= Y.x;
	j= Y.y;
	// Get the look direction for the current gxel (always look forwards)
	vec3 q = vec3((Z.xy - 0.5), 1.0);
	
	//Kamera sitzt an dieser Position
	vec3 p;










































	if( k == 7.0 )
	{
		p= vec3( -11.0, 3.0, -28.0 - j * 11.0);
		q.yz= r( q.yz, 0.2  );
		q.xz= r( q.xz, -2.0 + j );
	}
	else if( k == 8.0 )
	{
		p= vec3( -1.0, 1.0, -33.0 - j * 7.0);
		//q.yz= r( q.yz, 0.2  );
		//q.xz= r( q.xz, -2.0 + j );
	}
	else if( k == 9.0 )
	{
		p= vec3( Y.z * 18.0 + 3.0 * smoothstep( 0.3, 0.4, j ), Y.z * 3.0 + 3.0, j * -60.0 );
		q.yz= r( q.yz, 0.1  );
		q.xz= r( q.xz, j );
	}



























	

	/////////////////////////////////////////////////////////////////////
	//Debugzeug fuer Kamerasteuerung
	if( true )
	{
		p.x= gl_ModelViewMatrix[0][0];
		p.y= gl_ModelViewMatrix[0][1];
		p.z= gl_ModelViewMatrix[0][2];
	
		float a1= gl_ModelViewMatrix[1][1];
		float c1,s1;vec3 q1= vec3((Z.xy - 0.5), 1.0);
		c1 = cos(a1); s1 = sin(a1);
		q.y = c1 * q1.y - s1 * q1.z;
		q.x= q1.x;
		q.z = s1 * q1.y + c1 * q1.z;

		a1= gl_ModelViewMatrix[1][0];
		q1=q;
		c1 = cos(a1); s1 = sin(a1);
		q.x = c1 * q1.x + s1 * q1.z;
		q.z = -s1 * q1.x + c1 * q1.z;
	}
	//Ende Debugzeug fuer Kamerasteuerung
	/////////////////////////////////////////////////////////////////////

	
	q = normalize(q);

	vec3 b= vec3( .0,.0,.0 );
	float a=1.0;
	
	float t=w( q*666.0 )*0.2,y,z,d,m=0;
  
	while (m++<2.0)
	{
		
		//bis zu einer Oberflaeche steppen
		for (d=1.0;t<66.0 && d>t*.003;t+=max( 0.01, d+0.01) )
		{
			d = f(p+q*t);
		}
		
		if( t > 66.0 )
		{
			break;
		}
		
		//Startpunkt und Richtung fuer reflektierten Strahl;
		p+= q*t;
		//vec3 n = normal(p);

		vec2 e = vec2(0.04, 0.0);
		vec3 n= vec3( f(p + e.xyy) - f(p - e.xyy), f(p + e.yxy) - f(p - e.yxy), f(p + e.yyx) - f(p - e.yyx) );
		n= normalize(n);
		z= A(p);

		//d ab hier == Reflektion !!!









		vec3 c = vec3(0.95,1.0,0.95 );
		d= .18;






		if( z > D(p) )
		{
			z= D(p);









			c = vec3(1.0,0.0,0.0 );
			d= .15;





		}
		
		if( z > B(p) )
		{
			z= B(p);










			c = vec3(.1);
			d= .6;





		}
		
		if( z > C(p) )
		{
			z= C(p);
			c = vec3(0.0,0.6,0.8 ) * (0.9 - 0.15 / clamp(dot( n, q ), -1.0, -0.05));









			d= .1;
			e.y= 2.0;





		}
			
		n+= (w( p * e.y ) + w( p * e.y * 2.0 ) + w( p * e.y * 4.0 )) * e.x;
		n= normalize(n);
		q= reflect( q, n );

		y= 6.0;
		for (z=1.0;y>0.;y--)
		{ 
			z-=(y*.5-f(p+n*y*.5))/exp2(y);
		}
		c*= z;

		//lambertlight
		n.yz= r( n.yz, 0.6 );
		
		c*= .4 + .3 * ( 1.0 - abs( n.y - .9 ) );


		b+= a*c;//*(1.0-Reflect);
		a*= d;// Reflect * (1.0-t/tmax);
		t= 0.3;
	}
	
	p=vec3(0.8);
	q.yz= r( q.yz, 0.6 );
	p+= q.y * 0.2;
	if( m < 2 )
	{
		p*= vec3( 0.95, 1.1, 1.2);
	}
	
	if( q.y > 0.0 )
	{
		s(q.xz, 0.4, g/8.0);
		q.x= abs( q.x ) - .2;
		p+= pow( smoothstep(.2, .0, mix( abs(q.z),length(q.xz), step(0.0, q.x) ) ), 22.0 );
	}
	
	vec3 color = b + a*p;
	gl_FragColor.xyz = length(color) * (cos((Z.y + color)*g*2)*.125+.5);
}