Starry Infinite Tunnel v3

Shader code

shader_type canvas_item;

#define iResolution 1.0 / SCREEN_PIXEL_SIZE
#define fragCoord FRAGCOORD
#define iTime TIME

//uniform bool speed_up = false;
uniform float zoom : hint_range(0.0, 10.0, 0.1) = 2.0;
uniform float rotate_speed  : hint_range(-5.0, 5.0, 0.1) = 0.5;
uniform vec2 disp = vec2(0.5);
uniform bool transparent = false;

// ver. 3
// [mouse click] ->  speedup (ver. 2 mode)
// Endless Tunnel
// By: Brandon Fogerty
// bfogerty at gmail dot com

#ifdef GL_ES
precision mediump float;
#endif


/* discontinuous pseudorandom uniformly distributed in [-0.5, +0.5]^3 */
vec3 random3(vec3 c) {
	float j = 4096.0*sin(dot(c,vec3(17.0, 59.4, 15.0)));
	vec3 r;
	r.z = fract(512.0*j);
	j *= .125;
	r.x = fract(512.0*j);
	j *= .125;
	r.y = fract(512.0*j);
	return r-0.5;
}

const float F3 =  0.3333333;
const float G3 =  0.1666667;
float snoise(vec3 p) {

	vec3 s = floor(p + dot(p, vec3(F3)));
	vec3 x = p - s + dot(s, vec3(G3));

	vec3 e = step(vec3(0.0), x - x.yzx);
	vec3 i1 = e*(1.0 - e.zxy);
	vec3 i2 = 1.0 - e.zxy*(1.0 - e);

	vec3 x1 = x - i1 + G3;
	vec3 x2 = x - i2 + 2.0*G3;
	vec3 x3 = x - 1.0 + 3.0*G3;

	vec4 w, d;

	w.x = dot(x, x);
	w.y = dot(x1, x1);
	w.z = dot(x2, x2);
	w.w = dot(x3, x3);

	w = max(0.6 - w, 0.0);

	d.x = dot(random3(s), x);
	d.y = dot(random3(s + i1), x1);
	d.z = dot(random3(s + i2), x2);
	d.w = dot(random3(s + 1.0), x3);

	w *= w;
	w *= w;
	d *= w;

	return dot(d, vec4(52.0));
}



vec3 hsv2rgb(vec3 c){
    vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
    vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
    return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
}

const float pi = acos(-1.0);
float map(float v, float v_min, float v_max, float out1, float out2)
{
    if ( v_max - v_min == 0. )
        return out2;
        
     return (clamp(v,v_min,v_max) - v_min) / (v_max - v_min) * (out2-out1)+out1;
}

float fmod(float t,float a){
  return fract(t/a)*a;
}

float angle_diff_grad(float angle1, float angle2)
{
    float d = abs(angle1 - angle2);
    return d < 180. ? d : 360. - d;
}





vec4 tunnel_v2(vec2 uv, float black_hole_distance, float cut_factor) {

    float distance = 2. / length(uv);
    float angle = angle_diff_grad( map( atan(uv.y, uv.x), -PI,PI,0.,360.), 0. );
    
       if ( distance < black_hole_distance) {
      float normal_distance = map(distance,0.,black_hole_distance,1.,0.);
       float alpha = 
            pow(
           abs( snoise(vec3(angle, map(distance,0.,black_hole_distance,0.,5.) + iTime*1.5, -iTime/4. )))
           ,2.);
           
        if (alpha > cut_factor)
        {
           alpha = map(alpha, cut_factor, 1.,   0., normal_distance * 4.);
           float color = snoise(vec3(uv.x/1.,uv.y/1., normal_distance + iTime/2.));
           vec3 finalColor = hsv2rgb( vec3( color, normal_distance, alpha ));
           //vec3 finalColor = vec3( noise3( vec3(uv.x*10., uv.y*10., distance) ));
           return vec4( finalColor, 1.0 );           
         }
        }
         return vec4(0.,0.,0.,1.0); 
 
}


vec4 tunnel_v3(vec2 uv) {

    float far = zoom / length(uv);
    float angle = angle_diff_grad( map( atan(uv.y, uv.x), -PI,PI,0.,360.), sin(iTime/2.)*4. );
    
       if ( far < 25.) {
      
       float alpha = 
            pow(
               abs( snoise(vec3(angle, far +iTime*2.,0.)))
           ,16.);
           
        
        
           
           float color = fmod( iTime / 3.  + far / 25. ,5.);
           float dark  = map(far,0.,25.,1.,0.);
           vec3 finalColor = hsv2rgb( vec3( color, dark, map(alpha,0.,1.,0., 100. * dark ) ));
           
           return vec4( finalColor, 1.0 );           
         
        }
         return vec4(0.,0.,0.,1.0); 
 
}

vec2 rotate(vec2 _uv, float _speed, float _time){
	float changing_angle = _speed * _time;
	return _uv * mat2(vec2(sin(changing_angle), -cos(changing_angle)), vec2(cos(changing_angle), sin(changing_angle)));
}

void fragment()
{
    vec2 uv = (UV - disp);
    uv = rotate(uv, rotate_speed, TIME);
    COLOR = tunnel_v3(uv);
	//if (speed_up == true){
		//COLOR = tunnel_v2(uv, 20., 0.3);
	//}
	if (transparent == true){
		COLOR.a = step(0.05, COLOR.r * COLOR.g * COLOR.b);
	}
}