// Compatibility #ifdefs needed for parameters
#ifdef GL_ES
#define COMPAT_PRECISION mediump
#else
#define COMPAT_PRECISION
#endif

// Parameter lines go here:
#pragma parameter RETRO_PIXEL_SIZE "Retro Pixel Size" 0.84 0.0 1.0 0.01
#ifdef PARAMETER_UNIFORM
// All parameter floats need to have COMPAT_PRECISION in front of them
uniform COMPAT_PRECISION float RETRO_PIXEL_SIZE;
#else
#define RETRO_PIXEL_SIZE 0.84
#endif

#if defined(VERTEX)

#if __VERSION__ >= 130
#define COMPAT_VARYING out
#define COMPAT_ATTRIBUTE in
#define COMPAT_TEXTURE texture
#else
#define COMPAT_VARYING varying 
#define COMPAT_ATTRIBUTE attribute 
#define COMPAT_TEXTURE texture2D
#endif

#ifdef GL_ES
#define COMPAT_PRECISION mediump
#else
#define COMPAT_PRECISION
#endif

COMPAT_ATTRIBUTE vec4 VertexCoord;
COMPAT_ATTRIBUTE vec4 COLOR;
COMPAT_ATTRIBUTE vec4 TexCoord;
COMPAT_VARYING vec4 COL0;
COMPAT_VARYING vec4 TEX0;
// out variables go here as COMPAT_VARYING whatever

vec4 _oPosition1; 
uniform mat4 MVPMatrix;
uniform COMPAT_PRECISION int FrameDirection;
uniform COMPAT_PRECISION int FrameCount;
uniform COMPAT_PRECISION vec2 OutputSize;
uniform COMPAT_PRECISION vec2 TextureSize;
uniform COMPAT_PRECISION vec2 InputSize;

// compatibility #defines
#define vTexCoord TEX0.xy
#define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize
#define OutSize vec4(OutputSize, 1.0 / OutputSize)

void main()
{
    gl_Position = MVPMatrix * VertexCoord;
    TEX0.xy = VertexCoord.xy;
// Paste vertex contents here:
}

#elif defined(FRAGMENT)

#if __VERSION__ >= 130
#define COMPAT_VARYING in
#define COMPAT_TEXTURE texture
out vec4 FragColor;
#else
#define COMPAT_VARYING varying
#define FragColor gl_FragColor
#define COMPAT_TEXTURE texture2D
#endif

#ifdef GL_ES
#ifdef GL_FRAGMENT_PRECISION_HIGH
precision highp float;
#else
precision mediump float;
#endif
#define COMPAT_PRECISION mediump
#else
#define COMPAT_PRECISION
#endif

uniform COMPAT_PRECISION int FrameDirection;
uniform COMPAT_PRECISION int FrameCount;
uniform COMPAT_PRECISION vec2 OutputSize;
uniform COMPAT_PRECISION vec2 TextureSize;
uniform COMPAT_PRECISION vec2 InputSize;
uniform sampler2D Texture;
COMPAT_VARYING vec4 TEX0;
// in variables go here as COMPAT_VARYING whatever

// compatibility #defines
#define Source Texture
#define vTexCoord TEX0.xy

#define SourceSize vec4(TextureSize, 1.0 / TextureSize) //either TextureSize or InputSize
#define OutSize vec4(OutputSize, 1.0 / OutputSize)

// delete all 'params.' or 'registers.' or whatever in the fragment
float iGlobalTime = float(FrameCount)*0.025;
vec2 iResolution = OutputSize.xy;

// License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
// Created by S. Guillitte 2015
#define time iGlobalTime

vec2 cmul( vec2 a, vec2 b )  { return vec2( a.x*b.x - a.y*b.y, a.x*b.y + a.y*b.x ); }
vec2 csqr( vec2 a )  { return vec2( a.x*a.x - a.y*a.y, 2.*a.x*a.y  ); }


mat2 rot(float a) {
	return mat2(cos(a),sin(a),-sin(a),cos(a));	
}

float zoom=1.;

mat2 mr;



float field(in vec3 p) {
	
	float res = 0.;
	
    vec3 c = p;
    c.xz *= mr;
	for (int i = 0; i < 10; ++i) {
        p = 1.1*abs(p) / dot(p,p) -.6;
        p.yz= csqr(p.yz);
        
        res += exp(-6. * abs(dot(p,c))*dot(p.xz,p.xz));
        
	}
	return res/2.;
}



vec3 raycast( in vec3 ro, vec3 rd )
{
    float t = 8.0*zoom;
    float dt = .05*zoom;
    vec3 col= vec3(0.);
    for( int i=0; i<64; i++ )
	{
        
        float c = field(ro+t*rd);               
        t-=dt*(.3+c*c);
        col = .92*col+ .19*vec3(c, c*c, c*c*c);
		
    }
    
    return col;
}


void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
	mr = rot(time*.2);
    vec2 q = fragCoord.xy / iResolution.xy;
    vec2 p = -1.0 + 2.0 * q;
    p.x *= iResolution.x/iResolution.y;
    vec2 m = vec2(0.);
#ifdef MOUSE
	if( iMouse.z>0.0 )m = iMouse.xy/iResolution.xy*3.14;
#endif
    m-=.5;

    // camera

    vec3 ro = zoom*vec3(4.);
    ro.yz*=rot(m.y);
    ro.xz*=rot(m.x+ 0.1*time);
    vec3 ta = vec3( 0.0 , 0.0, 0.0 );
    vec3 ww = normalize( ta - ro );
    vec3 uu = normalize( cross(ww,vec3(0.0,1.0,0.0) ) );
    vec3 vv = normalize( cross(uu,ww));
    vec3 rd = normalize( p.x*uu + p.y*vv + 4.0*ww );
    

	// raymarch
    vec3 col = raycast(ro,rd);
    
	
	// shade
    
    col =  1.-.5 *(log(1.+col));
    col = clamp(col,0.,1.);
    fragColor = vec4( (col), 1.0 );

}

 void main(void)
{
  //just some shit to wrap shadertoy's stuff
  vec2 FragCoord = vTexCoord.xy*OutputSize.xy;
  mainImage(FragColor,FragCoord);
}
#endif