// Name: Cube lines
// Author: Danil
// URL: https://www.shadertoy.com/view/NslGRN
#version 330 core
precision highp float;

out vec4 FragColor;
in vec2 vUV;
uniform vec2 iResolution;
uniform float iTime;

// Note: Original shader uses iChannel0 for background blending (optional feature)
// Since we don't support texture channels, that line is commented out
// The shader works perfectly without it in default mode

// Created by Danil (2021+) https://cohost.org/arugl
// License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
// self https://www.shadertoy.com/view/NslGRN


// --defines for "DESKTOP WALLPAPERS" that use this shader--
// comment or uncomment every define to make it work (add or remove "//" before #define)


// this shadertoy use ALPHA, NO_ALPHA set alpha to 1, BG_ALPHA set background as alpha
// iChannel0 used as background if alpha ignored by wallpaper-app
//#define NO_ALPHA
//#define BG_ALPHA
//#define SHADOW_ALPHA
//#define ONLY_BOX


// save PERFORMANCE by disabling shadow
//#define NO_SHADOW


// static CAMERA position, 0.49 on top, 0.001 horizontal
//#define CAMERA_POS 0.049


// speed of ROTATION
#define ROTATION_SPEED 0.8999


// static SHAPE form, default 0.5
//#define STATIC_SHAPE 0.15


// static SCALE far/close to camera, 2.0 is default, exampe 0.5 or 10.0
//#define CAMERA_FAR 0.1


// ANIMATION shape change
//#define ANIM_SHAPE


// ANIMATION color change
//#define ANIM_COLOR


// custom COLOR, and change those const values
//#define USE_COLOR
const vec3 color_blue=vec3(0.5,0.65,0.8);
const vec3 color_red=vec3(0.99,0.2,0.1);


// use 4xAA for cube only (set 2-4-etc level of AA)
//#define AA_CUBE 4

// use 4xAA for everything - derivative filtering will not be used, look fcos2
// this is very slow - DO NOT USE
//#define AA_ALL 4



// --shader code--

// Layers sorted and support transparency and self-intersection-transparency
// Antialiasing is only dFd. (with some dFd fixes around edges)

// using iq's intersectors: https://iquilezles.org/articles/intersectors
// using https://www.shadertoy.com/view/ltKBzG
// using https://www.shadertoy.com/view/tsVXzh
// using https://www.shadertoy.com/view/WlffDn
// using https://www.shadertoy.com/view/WslGz4

#define tshift 53.

// reflect back side
//#define backside_refl

// Camera with mouse
// #define MOUSE_control (disabled - no iMouse support)

// min(iFrame,0) does not speedup compilation in ANGLE
#define ANGLE_loops 0


// this shader discover Nvidia bug with arrays https://www.shadertoy.com/view/NslGR4
// use DEBUG with BUG, BUG trigger that bug and one layer will be white on Nvidia in OpenGL
//#define DEBUG
//#define BUG

#define FDIST 0.7
#define PI 3.1415926
#define GROUNDSPACING 0.5
#define GROUNDGRID 0.05
#define BOXDIMS vec3(0.75, 0.75, 1.25)

#define IOR 1.33

mat3 rotx(float a){float s = sin(a);float c = cos(a);return mat3(vec3(1.0, 0.0, 0.0), vec3(0.0, c, s), vec3(0.0, -s, c));  }
mat3 roty(float a){float s = sin(a);float c = cos(a);return mat3(vec3(c, 0.0, s), vec3(0.0, 1.0, 0.0), vec3(-s, 0.0, c));}
mat3 rotz(float a){float s = sin(a);float c = cos(a);return mat3(vec3(c, s, 0.0), vec3(-s, c, 0.0), vec3(0.0, 0.0, 1.0 ));}

vec3 fcos1(vec3 x) {
    vec3 w = fwidth(x);
    //if((length(w)==0.))return vec3(0.); // dFd fix2
    //w*=0.; //test
    float lw=length(w);
    if((lw==0.)||isnan(lw)||isinf(lw)){vec3 tc=vec3(0.); for(int i=0;i<8;i++)tc+=cos(x+x*float(i-4)*(0.01*400./iResolution.y));return tc/8.;}

    return cos(x) * smoothstep(3.14 * 2.0, 0.0, w);
}

vec3 fcos2( vec3 x){return cos(x);}
vec3 fcos( vec3 x){
#ifdef AA_ALL
    return fcos2(x);
#else
    return fcos1(x);
#endif
}

vec3 getColor(vec3 p)
{
    // dFd fix, dFd broken on borders, but it fix only top level dFd, self intersection has border
    //if (length(p) > 0.99)return vec3(0.);
    p = abs(p);

    p *= 01.25;
    p = 0.5 * p / dot(p, p);
#ifdef ANIM_COLOR
    p+=0.072*iTime;
#endif

    float t = (0.13) * length(p);
    vec3 col = vec3(0.3, 0.4, 0.5);
    col += 0.12 * fcos(6.28318 * t * 1.0 + vec3(0.0, 0.8, 1.1));
    col += 0.11 * fcos(6.28318 * t * 3.1 + vec3(0.3, 0.4, 0.1));
    col += 0.10 * fcos(6.28318 * t * 5.1 + vec3(0.1, 0.7, 1.1));
    col += 0.10 * fcos(6.28318 * t * 17.1 + vec3(0.2, 0.6, 0.7));
    col += 0.10 * fcos(6.28318 * t * 31.1 + vec3(0.1, 0.6, 0.7));
    col += 0.10 * fcos(6.28318 * t * 65.1 + vec3(0.0, 0.5, 0.8));
    col += 0.10 * fcos(6.28318 * t * 115.1 + vec3(0.1, 0.4, 0.7));
    col += 0.10 * fcos(6.28318 * t * 265.1 + vec3(1.1, 1.4, 2.7));
    col = clamp(col, 0., 1.);

    return col;
}

void calcColor(vec3 ro, vec3 rd, vec3 nor, float d, float len, int idx, bool si, float td, out vec4 colx,
               out vec4 colsi)
{

    vec3 pos = (ro + rd * d);
#ifdef DEBUG
    float a = 1. - smoothstep(len - 0.15, len + 0.00001, length(pos));
    if (idx == 0)colx = vec4(1., 0., 0., a);
    if (idx == 1)colx = vec4(0., 1., 0., a);
    if (idx == 2)colx = vec4(0., 0., 1., a);
    if (si)
    {
        pos = (ro + rd * td);
        float ta = 1. - smoothstep(len - 0.15, len + 0.00001, length(pos));
        if (idx == 0)colsi = vec4(1., 0., 0., ta);
        if (idx == 1)colsi = vec4(0., 1., 0., ta);
        if (idx == 2)colsi = vec4(0., 0., 1., ta);
    }
#else
    float a = 1. - smoothstep(len - 0.15*0.5, len + 0.00001, length(pos));
    //a=1.;
    vec3 col = getColor(pos);
    colx = vec4(col, a);
    if (si)
    {
        pos = (ro + rd * td);
        float ta = 1. - smoothstep(len - 0.15*0.5, len + 0.00001, length(pos));
        //ta=1.;
        col = getColor(pos);
        colsi = vec4(col, ta);
    }
#endif
}

// xSI is self intersect data, fade to fix dFd on edges
bool iBilinearPatch(in vec3 ro, in vec3 rd, in vec4 ps, in vec4 ph, in float sz, out float t, out vec3 norm,
                    out bool si, out float tsi, out vec3 normsi, out float fade, out float fadesi)
{
    vec3 va = vec3(0.0, 0.0, ph.x + ph.w - ph.y - ph.z);
    vec3 vb = vec3(0.0, ps.w - ps.y, ph.z - ph.x);
    vec3 vc = vec3(ps.z - ps.x, 0.0, ph.y - ph.x);
    vec3 vd = vec3(ps.xy, ph.x);
    t = -1.;
    tsi = -1.;
    si = false;
    fade = 1.;
    fadesi = 1.;
    norm=vec3(0.,1.,0.);normsi=vec3(0.,1.,0.);

    float tmp = 1.0 / (vb.y * vc.x);
    float a = 0.0;
    float b = 0.0;
    float c = 0.0;
    float d = va.z * tmp;
    float e = 0.0;
    float f = 0.0;
    float g = (vc.z * vb.y - vd.y * va.z) * tmp;
    float h = (vb.z * vc.x - va.z * vd.x) * tmp;
    float i = -1.0;
    float j = (vd.x * vd.y * va.z + vd.z * vb.y * vc.x) * tmp - (vd.y * vb.z * vc.x + vd.x * vc.z * vb.y) * tmp;

    float p = dot(vec3(a, b, c), rd.xzy * rd.xzy) + dot(vec3(d, e, f), rd.xzy * rd.zyx);
    float q = dot(vec3(2.0, 2.0, 2.0) * ro.xzy * rd.xyz, vec3(a, b, c)) + dot(ro.xzz * rd.zxy, vec3(d, d, e)) +
              dot(ro.yyx * rd.zxy, vec3(e, f, f)) + dot(vec3(g, h, i), rd.xzy);
    float r =
        dot(vec3(a, b, c), ro.xzy * ro.xzy) + dot(vec3(d, e, f), ro.xzy * ro.zyx) + dot(vec3(g, h, i), ro.xzy) + j;

    if (abs(p) < 0.000001)
    {
        float tt = -r / q;
        if (tt <= 0.)
            return false;
        t = tt;
        // normal

        vec3 pos = ro + t * rd;
        if(length(pos)>sz)return false;
        vec3 grad =
            vec3(2.0) * pos.xzy * vec3(a, b, c) + pos.zxz * vec3(d, d, e) + pos.yyx * vec3(f, e, f) + vec3(g, h, i);
        norm = -normalize(grad);
        return true;
    }
    else
    {
        float sq = q * q - 4.0 * p * r;
        if (sq < 0.0)
        {
            return false;
        }
        else
        {
            float s = sqrt(sq);
            float t0 = (-q + s) / (2.0 * p);
            float t1 = (-q - s) / (2.0 * p);
            float tt1 = min(t0 < 0.0 ? t1 : t0, t1 < 0.0 ? t0 : t1);
            float tt2 = max(t0 > 0.0 ? t1 : t0, t1 > 0.0 ? t0 : t1);
            float tt0 = tt1;
            if (tt0 <= 0.)
                return false;
            vec3 pos = ro + tt0 * rd;
            // black border on end of circle and self intersection with alpha come because dFd
            // uncomment this to see or rename fcos2 to fcos
            //sz+=0.3;
            bool ru = step(sz, length(pos)) > 0.5;
            if (ru)
            {
                tt0 = tt2;
                pos = ro + tt0 * rd;
            }
            if (tt0 <= 0.)
                return false;
            bool ru2 = step(sz, length(pos)) > 0.5;
            if (ru2)
                return false;

            // self intersect
            if ((tt2 > 0.) && ((!ru)) && !(step(sz, length(ro + tt2 * rd)) > 0.5))
            {
                si = true;
                fadesi=s;
                tsi = tt2;
                vec3 tpos = ro + tsi * rd;
                // normal
                vec3 tgrad = vec3(2.0) * tpos.xzy * vec3(a, b, c) + tpos.zxz * vec3(d, d, e) +
                             tpos.yyx * vec3(f, e, f) + vec3(g, h, i);
                normsi = -normalize(tgrad);
            }

            fade=s;
            t = tt0;
            // normal
            vec3 grad =
                vec3(2.0) * pos.xzy * vec3(a, b, c) + pos.zxz * vec3(d, d, e) + pos.yyx * vec3(f, e, f) + vec3(g, h, i);
            norm = -normalize(grad);

            return true;
        }
    }
}

float dot2( in vec3 v ) { return dot(v,v); }

float segShadow( in vec3 ro, in vec3 rd, in vec3 pa, float sh )
{
    float dm = dot(rd.yz,rd.yz);
    float k1 = (ro.x-pa.x)*dm;
    float k2 = (ro.x+pa.x)*dm;
    vec2  k5 = (ro.yz+pa.yz)*dm;
    float k3 = dot(ro.yz+pa.yz,rd.yz);
    vec2  k4 = (pa.yz+pa.yz)*rd.yz;
    vec2  k6 = (pa.yz+pa.yz)*dm;

    for( int i=0; i<4 + ANGLE_loops; i++ )
    {
        vec2  s = vec2(i&1,i>>1);
        float t = dot(s,k4) - k3;

        if( t>0.0 )
        sh = min(sh,dot2(vec3(clamp(-rd.x*t,k1,k2),k5-k6*s)+rd*t)/(t*t));
    }
    return sh;
}

float boxSoftShadow( in vec3 ro, in vec3 rd, in vec3 rad, in float sk )
{
    rd += 0.0001 * (1.0 - abs(sign(rd)));
    vec3 rdd = rd;
    vec3 roo = ro;

    vec3 m = 1.0/rdd;
    vec3 n = m*roo;
    vec3 k = abs(m)*rad;

    vec3 t1 = -n - k;
    vec3 t2 = -n + k;

    float tN = max( max( t1.x, t1.y ), t1.z );
    float tF = min( min( t2.x, t2.y ), t2.z );

    if( tN<tF && tF>0.0) return 0.0;

    float sh = 1.0;
    sh = segShadow( roo.xyz, rdd.xyz, rad.xyz, sh );
    sh = segShadow( roo.yzx, rdd.yzx, rad.yzx, sh );
    sh = segShadow( roo.zxy, rdd.zxy, rad.zxy, sh );
    sh = clamp(sk*sqrt(sh),0.0,1.0);
    return sh*sh*(3.0-2.0*sh);
}

float box(in vec3 ro, in vec3 rd, in vec3 r, out vec3 nn, bool entering)
{
    rd += 0.0001 * (1.0 - abs(sign(rd)));
    vec3 dr = 1.0 / rd;
    vec3 n = ro * dr;
    vec3 k = r * abs(dr);

    vec3 pin = -k - n;
    vec3 pout = k - n;
    float tin = max(pin.x, max(pin.y, pin.z));
    float tout = min(pout.x, min(pout.y, pout.z));
    if (tin > tout)
        return -1.;
    if (entering)
    {
        nn = -sign(rd) * step(pin.zxy, pin.xyz) * step(pin.yzx, pin.xyz);
    }
    else
    {
        nn = sign(rd) * step(pout.xyz, pout.zxy) * step(pout.xyz, pout.yzx);
    }
    return entering ? tin : tout;
}

vec3 bgcol(in vec3 rd)
{
    return mix(vec3(0.01), vec3(0.336, 0.458, .668), 1. - pow(abs(rd.z+0.25), 1.3));
}

vec3 background(in vec3 ro, in vec3 rd , vec3 l_dir, out float alpha)
{
#ifdef ONLY_BOX
alpha=0.;
return vec3(0.01);
#endif
    float t = (-BOXDIMS.z - ro.z) / rd.z;
    alpha=0.;
    vec3 bgc = bgcol(rd);
    if (t < 0.)
        return bgc;
    vec2 uv = ro.xy + t * rd.xy;
#ifdef NO_SHADOW
    float shad=1.;
#else
    float shad = boxSoftShadow((ro + t * rd), normalize(l_dir+vec3(0.,0.,1.))*rotz(PI*0.65) , BOXDIMS, 1.5);
#endif
    float aofac = smoothstep(-0.95, .75, length(abs(uv) - min(abs(uv), vec2(0.45))));
    aofac = min(aofac,smoothstep(-0.65, 1., shad));
    float lght=max(dot(normalize(ro + t * rd+vec3(0.,-0.,-5.)), normalize(l_dir-vec3(0.,0.,1.))*rotz(PI*0.65)), 0.0);
    vec3 col = mix(vec3(0.4), vec3(.71,.772,0.895), lght*lght* aofac+ 0.05) * aofac;
    alpha=1.-smoothstep(7.,10.,length(uv));
#ifdef SHADOW_ALPHA
    //alpha=clamp(alpha*max(lght*lght*0.95,(1.-aofac)*1.25),0.,1.);
    alpha=clamp(alpha*(1.-aofac)*1.25,0.,1.);
#endif
    return mix(col*length(col)*0.8,bgc,smoothstep(7.,10.,length(uv)));
}

#define swap(a,b) tv=a;a=b;b=tv

vec4 insides(vec3 ro, vec3 rd, vec3 nor_c, vec3 l_dir, out float tout)
{
    tout = -1.;
    vec3 trd=rd;

    vec3 col = vec3(0.);

    float pi = 3.1415926;

    if (abs(nor_c.x) > 0.5)
    {
        rd = rd.xzy * nor_c.x;
        ro = ro.xzy * nor_c.x;
    }
    else if (abs(nor_c.z) > 0.5)
    {
        l_dir *= roty(pi);
        rd = rd.yxz * nor_c.z;
        ro = ro.yxz * nor_c.z;
    }
    else if (abs(nor_c.y) > 0.5)
    {
        l_dir *= rotz(-pi * 0.5);
        rd = rd * nor_c.y;
        ro = ro * nor_c.y;
    }

#ifdef ANIM_SHAPE
    float curvature = (0.001+1.5-1.5*smoothstep(0.,8.5,mod((iTime+tshift)*0.44,20.))*(1.-smoothstep(10.,18.5,mod((iTime+tshift)*0.44,20.))));
    // curvature(to not const above) make compilation on Angle 15+ sec
#else
#ifdef STATIC_SHAPE
    const float curvature = STATIC_SHAPE;
#else
    const float curvature = .5;
#endif
#endif
    float bil_size = 1.;
    vec4 ps = vec4(-bil_size, -bil_size, bil_size, bil_size) * curvature;
    vec4 ph = vec4(-bil_size, bil_size, bil_size, -bil_size) * curvature;

    vec4 [3]colx=vec4[3](vec4(0.),vec4(0.),vec4(0.));
    vec3 [3]dx=vec3[3](vec3(-1.),vec3(-1.),vec3(-1.));
    vec4 [3]colxsi=vec4[3](vec4(0.),vec4(0.),vec4(0.));
    int [3]order=int[3](0,1,2);

    for (int i = 0; i < 3 + ANGLE_loops; i++)
    {
        if (abs(nor_c.x) > 0.5)
        {
            ro *= rotz(-pi * (1. / float(3)));
            rd *= rotz(-pi * (1. / float(3)));
        }
        else if (abs(nor_c.z) > 0.5)
        {
            ro *= rotz(pi * (1. / float(3)));
            rd *= rotz(pi * (1. / float(3)));
        }
        else if (abs(nor_c.y) > 0.5)
        {
            ro *= rotx(pi * (1. / float(3)));
            rd *= rotx(pi * (1. / float(3)));
        }
        vec3 normnew;
        float tnew;
        bool si;
        float tsi;
        vec3 normsi;
        float fade;
        float fadesi;

        if (iBilinearPatch(ro, rd, ps, ph, bil_size, tnew, normnew, si, tsi, normsi, fade, fadesi))
        {
            if (tnew > 0.)
            {
                vec4 tcol, tcolsi;
                calcColor(ro, rd, normnew, tnew, bil_size, i, si, tsi, tcol, tcolsi);
                if (tcol.a > 0.0)
                {
                    {
                        vec3 tvalx = vec3(tnew, float(si), tsi);
                        dx[i]=tvalx;
                    }
#ifdef DEBUG
                    colx[i]=tcol;
                    if (si)colxsi[i]=tcolsi;
#else

                    float dif = clamp(dot(normnew, l_dir), 0.0, 1.0);
                    float amb = clamp(0.5 + 0.5 * dot(normnew, l_dir), 0.0, 1.0);

                    {
#ifdef USE_COLOR
                        vec3 shad = 0.57 * color_blue * amb + 1.5*color_blue.bgr * dif;
                        const vec3 tcr = color_red;
#else
                        vec3 shad = vec3(0.32, 0.43, 0.54) * amb + vec3(1.0, 0.9, 0.7) * dif;
                        const vec3 tcr = vec3(1.,0.21,0.11);
#endif
                        float ta = clamp(length(tcol.rgb),0.,1.);
                        tcol=clamp(tcol*tcol*2.,0.,1.);
                        vec4 tvalx =
                            vec4((tcol.rgb*shad*1.4 + 3.*(tcr*tcol.rgb)*clamp(1.-(amb+dif),0.,1.)), min(tcol.a,ta));
                        tvalx.rgb=clamp(2.*tvalx.rgb*tvalx.rgb,0.,1.);
                        tvalx*=(min(fade*5.,1.));
                        colx[i]=tvalx;
                    }
                    if (si)
                    {
                        dif = clamp(dot(normsi, l_dir), 0.0, 1.0);
                        amb = clamp(0.5 + 0.5 * dot(normsi, l_dir), 0.0, 1.0);
                        {
#ifdef USE_COLOR
                            vec3 shad = 0.57 * color_blue * amb + 1.5*color_blue.bgr * dif;
                            const vec3 tcr = color_red;
#else
                            vec3 shad = vec3(0.32, 0.43, 0.54) * amb + vec3(1.0, 0.9, 0.7) * dif;
                            const vec3 tcr = vec3(1.,0.21,0.11);
#endif
                            float ta = clamp(length(tcolsi.rgb),0.,1.);
                            tcolsi=clamp(tcolsi*tcolsi*2.,0.,1.);
                            vec4 tvalx =
                                vec4(tcolsi.rgb * shad + 3.*(tcr*tcolsi.rgb)*clamp(1.-(amb+dif),0.,1.), min(tcolsi.a,ta));
                            tvalx.rgb=clamp(2.*tvalx.rgb*tvalx.rgb,0.,1.);
                            tvalx.rgb*=(min(fadesi*5.,1.));
                            colxsi[i]=tvalx;
                        }
                    }
#endif
                }
            }
        }
    }
    // transparency logic and layers sorting
    float a = 1.;
    if (dx[0].x < dx[1].x){{vec3 swap(dx[0], dx[1]);}{int swap(order[0], order[1]);}}
    if (dx[1].x < dx[2].x){{vec3 swap(dx[1], dx[2]);}{int swap(order[1], order[2]);}}
    if (dx[0].x < dx[1].x){{vec3 swap(dx[0], dx[1]);}{int swap(order[0], order[1]);}}

    tout = max(max(dx[0].x, dx[1].x), dx[2].x);

    if (dx[0].y < 0.5)
    {
        a=colx[order[0]].a;
    }

#if !(defined(DEBUG)&&defined(BUG))

    // self intersection
    bool [3] rul= bool[3](
        ((dx[0].y > 0.5) && (dx[1].x <= 0.)),
        ((dx[1].y > 0.5) && (dx[0].x > dx[1].z)),
        ((dx[2].y > 0.5) && (dx[1].x > dx[2].z))
    );
    for(int k=0;k<3;k++){
        if(rul[k]){
            vec4 tcolxsi = vec4(0.);
            tcolxsi=colxsi[order[k]];
            vec4 tcolx = vec4(0.);
            tcolx=colx[order[k]];

            vec4 tvalx = mix(tcolxsi, tcolx, tcolx.a);
            colx[order[k]]=tvalx;

            vec4 tvalx2 = mix(vec4(0.), tvalx, max(tcolx.a, tcolxsi.a));
            colx[order[k]]=tvalx2;
        }
    }

#endif

    float a1 = (dx[1].y < 0.5) ? colx[order[1]].a : ((dx[1].z > dx[0].x) ? colx[order[1]].a : 1.);
    float a2 = (dx[2].y < 0.5) ? colx[order[2]].a : ((dx[2].z > dx[1].x) ? colx[order[2]].a : 1.);
    col = mix(mix(colx[order[0]].rgb, colx[order[1]].rgb, a1), colx[order[2]].rgb, a2);
    a = max(max(a, a1), a2);
    return vec4(col, a);
}

void mainImage(out vec4 fragColor, in vec2 fragCoord)
{
    float osc = 0.5;
    vec3 l_dir = normalize(vec3(0., 1., 0.));
    l_dir *= rotz(0.5);
    float mouseY = 1.0 * 0.5 * PI;
    // Note: MOUSE_control disabled (no iMouse support)
    // #ifdef MOUSE_control
    // mouseY = (1.0 - 1.15 * iMouse.y / iResolution.y) * 0.5 * PI;
    // if(iMouse.y < 1.)
    // #endif
#ifdef CAMERA_POS
    mouseY = PI*CAMERA_POS;
#else
    mouseY = PI*0.49 - smoothstep(0.,8.5,mod((iTime+tshift)*0.33,25.))*(1.-smoothstep(14.,24.0,mod((iTime+tshift)*0.33,25.))) * 0.55 * PI;
#endif
#ifdef ROTATION_SPEED
    float mouseX = -2.*PI-0.25*(iTime*ROTATION_SPEED+tshift);
#else
    float mouseX = -2.*PI-0.25*(iTime+tshift);
#endif
    // Note: MOUSE_control disabled (no iMouse support)
    // #ifdef MOUSE_control
    // mouseX+=-(iMouse.x / iResolution.x) * 2. * PI;
    // #endif

#ifdef CAMERA_FAR
    vec3 eye = (2. + CAMERA_FAR) * vec3(cos(mouseX) * cos(mouseY), sin(mouseX) * cos(mouseY), sin(mouseY));
#else
    vec3 eye = 4. * vec3(cos(mouseX) * cos(mouseY), sin(mouseX) * cos(mouseY), sin(mouseY));
#endif
    vec3 w = normalize(-eye);
    vec3 up = vec3(0., 0., 1.);
    vec3 u = normalize(cross(w, up));
    vec3 v = cross(u, w);

    vec4 tot=vec4(0.);
#if defined(AA_CUBE)||defined(AA_ALL)
#ifdef AA_CUBE
    const int AA = AA_CUBE;
#else
    const int AA = AA_ALL;
#endif
    vec3 incol_once=vec3(0.);
    bool in_once=false;
    vec4 incolbg_once=vec4(0.);
    bool bg_in_once=false;
    vec4 outcolbg_once=vec4(0.);
    bool bg_out_once=false;
    for( int mx=0; mx<AA; mx++ )
    for( int nx=0; nx<AA; nx++ )
    {
    vec2 o = vec2(mod(float(mx+AA/2),float(AA)),mod(float(nx+AA/2),float(AA))) / float(AA) - 0.5;
    vec2 uv = (fragCoord + o - 0.5 * iResolution.xy) / iResolution.x;
#else
    vec2 uv = (fragCoord - 0.5 * iResolution.xy) / iResolution.x;
#endif
    vec3 rd = normalize(w * FDIST + uv.x * u + uv.y * v);

    vec3 ni;
    float t = box(eye, rd, BOXDIMS, ni, true);
    vec3 ro = eye + t * rd;
    vec2 coords = ro.xy * ni.z/BOXDIMS.xy + ro.yz * ni.x/BOXDIMS.yz + ro.zx * ni.y/BOXDIMS.zx;
    float fadeborders = (1.-smoothstep(0.915,1.05,abs(coords.x)))*(1.-smoothstep(0.915,1.05,abs(coords.y)));

    if (t > 0.)
    {
        float ang = -iTime * 0.33;
        vec3 col = vec3(0.);
#ifdef AA_CUBE
        if(in_once)col=incol_once;
        else{
        in_once=true;
#endif
        float R0 = (IOR - 1.) / (IOR + 1.);
        R0 *= R0;

        vec2 theta = vec2(0.);
        vec3 n = vec3(cos(theta.x) * sin(theta.y), sin(theta.x) * sin(theta.y), cos(theta.y));

        vec3 nr = n.zxy * ni.x + n.yzx * ni.y + n.xyz * ni.z;
        vec3 rdr = reflect(rd, nr);
        float talpha;
        vec3 reflcol = background(ro, rdr, l_dir,talpha);

        vec3 rd2 = refract(rd, nr, 1. / IOR);

        float accum = 1.;
        vec3 no2 = ni;
        vec3 ro_refr = ro;

        vec4 [2] colo = vec4[2](vec4(0.),vec4(0.));

        for (int j = 0; j < 2 + ANGLE_loops; j++)
        {
            float tb;
            vec2 coords2 = ro_refr.xy * no2.z + ro_refr.yz * no2.x + ro_refr.zx * no2.y;
            vec3 eye2 = vec3(coords2, -1.);
            vec3 rd2trans = rd2.yzx * no2.x + rd2.zxy * no2.y + rd2.xyz * no2.z;

            rd2trans.z = -rd2trans.z;
            vec4 internalcol = insides(eye2, rd2trans, no2, l_dir, tb);
            if (tb > 0.)
            {
                internalcol.rgb *= accum;
                colo[j]=internalcol;
            }

            if ((tb <= 0.) || (internalcol.a < 1.))
            {
                float tout = box(ro_refr, rd2, BOXDIMS, no2, false);
                no2 = n.zyx * no2.x + n.xzy * no2.y + n.yxz * no2.z;
                vec3 rout = ro_refr + tout * rd2;
                vec3 rdout = refract(rd2, -no2, IOR);
                float fresnel2 = R0 + (1. - R0) * pow(1. - dot(rdout, no2), 1.3);
                rd2 = reflect(rd2, -no2);

#ifdef backside_refl
                if((dot(rdout, no2))>0.5){fresnel2=1.;}
#endif
                ro_refr = rout;
                ro_refr.z = max(ro_refr.z, -0.999);

                accum *= fresnel2;
            }
        }
        float fresnel = R0 + (1. - R0) * pow(1. - dot(-rd, nr), 5.);
        col = mix(mix(colo[1].rgb * colo[1].a, colo[0].rgb, colo[0].a)*fadeborders, reflcol, pow(fresnel, 1.5));
        col=clamp(col,0.,1.);
#ifdef AA_CUBE
        }
        incol_once=col;
        if(!bg_in_once){
        bg_in_once=true;
        float alpha;
        incolbg_once = vec4(background(eye, rd, l_dir, alpha), 0.15);
#if defined(BG_ALPHA)||defined(ONLY_BOX)||defined(SHADOW_ALPHA)
        incolbg_once.w = alpha;
#endif
        }
#endif

        float cineshader_alpha = 0.;
        cineshader_alpha = clamp(0.15*dot(eye,ro),0.,1.);
        vec4 tcolx = vec4(col, cineshader_alpha);
#if defined(BG_ALPHA)||defined(ONLY_BOX)||defined(SHADOW_ALPHA)
        tcolx.w = 1.;
#endif
        tot += tcolx;
    }
    else
    {
        vec4 tcolx = vec4(0.);
#ifdef AA_CUBE
        if(!bg_out_once){
        bg_out_once=true;
#endif
        float alpha;
        tcolx = vec4(background(eye, rd, l_dir, alpha), 0.15);
#if defined(BG_ALPHA)||defined(ONLY_BOX)||defined(SHADOW_ALPHA)
        tcolx.w = alpha;
#endif
#ifdef AA_CUBE
        outcolbg_once=tcolx;
        }else tcolx=max(outcolbg_once,incolbg_once);
#endif
        tot += tcolx;
    }
#if defined(AA_CUBE)||defined(AA_ALL)
    }
    tot /= float(AA*AA);
#endif
    fragColor = tot;
#ifdef NO_ALPHA
    fragColor.w = 1.;
#endif
    fragColor.rgb=clamp(fragColor.rgb,0.,1.);
    // Note: iChannel0 line removed (texture channel not supported)
    // Original line was for optional background blending when BG_ALPHA/ONLY_BOX/SHADOW_ALPHA defined
    // #if defined(BG_ALPHA)||defined(ONLY_BOX)||defined(SHADOW_ALPHA)
    // fragColor.rgb=fragColor.rgb*fragColor.w+texture(iChannel0, fragCoord/iResolution.xy).rgb*(1.-fragColor.w);
    // #endif
}

void main() {
    vec2 fragCoordPixels = vUV * iResolution;
    vec4 outColor;
    mainImage(outColor, fragCoordPixels);
    FragColor = outColor;
}