// WORMHOLE - watch for a little while
// better version.

#ifdef GL_ES
precision mediump float;
#endif
 
 
uniform float time;
uniform vec2 mouse;
uniform vec2 resolution;


#define iterations 9
#define formuparam2 0.79
 
#define volsteps 9
#define stepsize 0.190
 
#define zoom 0.500
#define tile  0.85
#define speed2  0.30
 
#define brightness (0.02 * (1.5 - 0.5*sus_sin(0.5*time)))
#define darkmatter 0.400
#define distfading 0.560
#define saturation 0.800


#define transverseSpeed zoom*.005
//#define cloud (0.31 * (1.5 - 0.5*sus_sin(0.5*time)))


#define cloud 0.3
#define power1 0.5
#define power2  -2.0
 

#define pi 3.141592653589

float triangle(float x, float a)
{
 
 
float output2 = 2.0*abs(  2.0*  ( (x/a) - floor( (x/a) + 0.5) ) ) - 1.0;
return output2;
}




float trapezoid(float x, float a)
{
 
 
float output2 = 2.0*abs(  2.0*  ( (x/a) - floor( (x/a) + 0.5) ) ) - 1.0;
	
	float output3 = 2.0*clamp(output2, -1., 1.);
	
return output2;
}





float sus_sin(float x)
{
	float x1 = x + (3.0*pi/2.0);
	float output1 = abs(sin(x1));
	float output2 = (clamp((1.0/(sin(pi/10.0))) * sin((1.0/5.0)*x1),-1.0,1.0));
	
	float output3 = max(output1,abs(output2));
	
	return output3 * sign(output2);
	
}



float smooth_stair(float x, float period, float strechiness, float shift)
{
	
	float output1 = (  (1.0/(1.0 + exp(-1.0*mod(((1.0*(strechiness*(x)-shift ))),strechiness*period)  + (strechiness*period / 2.0) ))) + (floor(((strechiness*(x)-shift))/(strechiness*period))) );
	
	return output1;
}


float field(in vec3 p) {
	
	float strength = 17. + .03 * log(1.e-6 + fract(sin(time) * 4373.11));
	float accum = 0.;
	float prev = 0.;
	float tw = 0.;
	

	for (int i = 0; i < 2; ++i) {
		float mag = dot(p, p);
		p = abs(p) / mag + vec3(-.5, -.8 + 0.1*sin(time*0.7 + 2.0), -1.1+0.3*cos(time*0.3));
		float w = exp(-float(i) / 7.);
		accum += w * exp(-strength * pow(abs(mag - prev), 2.3));
		tw += w;
		prev = mag;
	}
	return max(0., 5. * accum / tw - .7);
}



void main()
{
   	//mouse rotation
	float a_xz = 0.9;
	float a_yz = -.6;
	float a_xy = 0.9 + time*0.01;
	
	
	mat2 rot_xz = mat2(cos(a_xz),sin(a_xz),-sin(a_xz),cos(a_xz));
	
	mat2 rot_yz = mat2(cos(a_yz),sin(a_yz),-sin(a_yz),cos(a_yz));
		
	mat2 rot_xy = mat2(cos(a_xy),sin(a_xy),-sin(a_xy),cos(a_xy));
	
	
     	vec2 uv2 = 2. * gl_FragCoord.xy / resolution.xy - 1.;
	vec2 uvs = uv2 * resolution.xy / max(resolution.x, resolution.y);
	
	
		vec3 from=vec3(0.0, 0.0,0.0);
 
                               
	
	uvs *= -3.0*rot_xy;
	
	vec2 from_change = 1.0*vec2((mouse.x-0.5), (mouse.y-0.5));
	
	from_change *= +3.0*rot_xy;
	
	
	from.xy += from_change;
	
//        from.x -= 5.0*(mouse.x-0.5);
 //       from.y -= 5.0*(mouse.y-0.5);

	
	float time2 = time;
               
        float speed = speed2;
       
	
	//speed = 0.005 * cos(time2*0.02 + 3.1415926/4.0);
        
	speed = -0.003 * cos((cos(0.02*time)));
	
	//speed = -0.001* clamp((0.5 - 2.*cos(0.05*time)),0.,1.);
        
	 
	
	//speed = 0.0;

	
    	float formuparam = formuparam2;

	
    
	

	
	

	
	// any ideas on how to make this wrap without the discontinuity?

	//float a = (atan(uvs.y,uvs.x));
		float a = abs(atan(uvs.y,uvs.x));
		float r = pow( pow(uvs.x*uvs.x,1.3) + pow(uvs.y*uvs.y,1.3), 1.0/(6.) );
	
	

	//vec2 uv = vec2( clamp((0.5 + 3.*cos(0.02*time)),0.,1.)*uvs.x + clamp((0.5 - 3.*cos(0.02*time)),0.,1.)*(0.3)/pow(r,1.), clamp((0.5 + 3.*cos(0.02*time)),0.,1.)*uvs.y + clamp((0.5 - 3.*cos(0.02*time)),0.,1.)*(1.*a/3.1415927) );

	
	
	vec2 uv = vec2( ((0.5 + 0.5*sus_sin(0.5*time)))*uvs.x + ((0.5 - 0.5*sus_sin(0.5*time)))*(0.3)/pow(r,1.), ((0.5 + 0.5*sus_sin(0.5*time)))*uvs.y + ((0.5 - 0.5*sus_sin(0.5*time)))*(1.*a/3.1415927) );

	
	
//	uv = uvs;
	
	//uv *= rot_xy;
	
	
	
	
	
	
	float v2 =1.0;
	
	vec3 dir=vec3(uv*zoom,1.);
 
            
	from.y -= 20.0;
	//from.y -= 1.5*smooth_stair(time, 10.0*pi, 2.0, -5.0);
               
	//from.x -= 50.0*(0.5 - 3.*cos(0.02*time));
	
	//from.x -= time*.3*(0.5 - 0.5*sus_sin(0.5*time));
	
	vec3 forward = vec3(0.,0.,1.);
               
	
	from.x += transverseSpeed*(1.0)*cos(0.01*time);
		from.y += transverseSpeed*(1.0)*sin(0.01*time);
	
	from.z += 0.003*time;
	
	//from.x -= 0.2*(0.1 - 0.1*sus_sin(0.1*time))*time;
	
	
	dir.xy*=rot_xy;
	forward.xy *= rot_xy;

	dir.xz*=rot_xz;
	forward.xz *= rot_xz;
		
	
	dir.yz*= rot_yz;
	forward.yz *= rot_yz;
	 

	
	from.xy*=-rot_xy;
	from.xz*=rot_xz;
	from.yz*= rot_yz;
	 
	
	//zoom
	float zooom = (time2-3311.)*speed;
	from += forward* zooom;
	float sampleShift = mod( zooom, stepsize );
	 
	float zoffset = -sampleShift;
	sampleShift /= stepsize; // make from 0 to 1


	
	//volumetric rendering
	float s=0.24;
	float s3 = s + stepsize/2.0;
	vec3 v=vec3(0.);
	float t3 = 0.0;
	
	
	vec3 backCol2 = vec3(0.);
	for (int r=0; r<volsteps; r++) {
		vec3 p2=from+(s+zoffset)*dir;// + vec3(0.,0.,zoffset);
		vec3 p3=from+(s3+zoffset)*dir;// + vec3(0.,0.,zoffset);
		
		p2 = abs(vec3(tile)-mod(p2,vec3(tile*2.))); // tiling fold
		p3 = abs(vec3(tile)-mod(p3,vec3(tile*2.))); // tiling fold
		
		#ifdef cloud
		t3 = field(p3);
		#endif
		
		float pa,a=pa=0.;
		for (int i=0; i<iterations; i++) {
			p2=abs(p2)/dot(p2,p2)-formuparam; // the magic formula
			//p=abs(p)/max(dot(p,p),0.005)-formuparam; // another interesting way to reduce noise
			float D = abs(length(p2)-pa); // absolute sum of average change
			a += i > 7 ? min( 12., D) : D;
			pa=length(p2);
		}
		
		
		//float dm=max(0.,darkmatter-a*a*.001); //dark matter
		a*=a*a; // add contrast
		//if (r>3) fade*=1.-dm; // dark matter, don't render near
		// brightens stuff up a bit
		float s1 = s+zoffset;
		// need closed form expression for this, now that we shift samples
		float fade = pow(distfading,max(0.,float(r)-sampleShift));
		
		
		//t3 += fade;
		
		v+=fade;
	       		//backCol2 -= fade;

		// fade out samples as they approach the camera
		if( r == 0 )
			fade *= (1. - (sampleShift));
		// fade in samples as they approach from the distance
		if( r == volsteps-1 )
			fade *= sampleShift;
		v+=vec3(s1,s1*s1,s1*s1*s1*s1)*a*brightness*fade; // coloring based on distance
		
		backCol2 += mix(.4, 1., v2) * vec3(1.8 * t3 * t3 * t3, 1.4 * t3 * t3, t3) * fade;

		
		s+=stepsize;
		s3 += stepsize;
		
		
		
		}
		       
	v=mix(vec3(length(v)),v,saturation); //color adjust
	 
	
	

	vec4 forCol2 = vec4(v*.01,1.);
	
	#ifdef cloud
	backCol2 *= cloud;
	#endif
	
	backCol2.b *= 1.8;

	backCol2.r *= 0.05;
	

	
	backCol2.b = 0.5*mix(backCol2.g, backCol2.b, 0.8);
	backCol2.g = 0.0;

	backCol2.bg = mix(backCol2.gb, backCol2.bg, 0.5*(cos(time*0.01) + 1.0));
	
	vec4 newCol = (forCol2 + vec4(backCol2, 1.0)) * pow(r,1.5*((0.5 - 0.5*sus_sin(0.5*time))));
	
	//gl_FragColor = forCol2 + vec4(backCol2, 1.0);
	gl_FragColor = newCol;
}