paper_scroll_timeline.glsl

/*
  Another GLSL deep-Refactoring project
  Original shader: https://www.shadertoy.com/view/WtjGRc
  by Ping2_0
*/

/*
 * Ping 2.0 14/06/2019
 * 
 * TODO : 	Cloud rocking
*/
const vec3 c0 = vec3(.042, 0.530, 0.159);
const vec3 c1 = vec3(.142, 0.630, 0.259);
const vec3 c2 = vec3(0.242, 0.730, 0.359);
const vec3 c3 = vec3(0.342, 0.830, 0.459);
const vec3 c4 = vec3(0.442, 0.930, 0.559);

const vec3 c5 = vec3(1);
const vec3 c6 = vec3(0.95, 0.95, 1.0);
const vec3 c7 = vec3(0.9, 0.9, 1.0);
//const vec3 c8 = vec3(0.85, 0.85 ,1.0);
//const vec3 c9 = vec3(0.8,0.85, 0.95);

// min dist 2 circles (or ellipsis)
#define GRND1 min(length(fract(op)*vec2(1, 3) - vec2(0.5,0.18)) - 0.3,     length(fract(op+vec2(0.5, 0))*vec2(1, 2) - vec2(0.5,0.09)) - 0.35)
#define GRND2 min(length(fract(op)*vec2(1.2, 2.5) - vec2(0.5,0.45)) - 0.4, length(fract(op+vec2(0.65, 0))*vec2(1, 1.4) - vec2(0.5,0.25)) - 0.35)
#define GRND3 min(length(fract(op)-vec2(0.5,0.3))-0.35, length(fract(op+vec2(0.5, 0))-vec2(0.5,0.25))-0.3)
#define GRND4 min(length(fract(op)-vec2(0.5,0.1))-0.3, length(fract(op+vec2(0.5, 0))-vec2(0.5,0.1))-0.4)
#define GRND5 min(length(fract(op)-vec2(0.5,0.2))-0.5, length(fract(op+vec2(0.5, 0))-vec2(0.5,0.2))-0.5)

#define txc(c, n, f) c*n + (1.0125-n)*texture(iChannel0, op*f).r

vec3 ground(in vec2 u, in vec3 c, in float shadow_pos) {
  if(u.y < 0.4) {
    const float b = 0.005; //blur
    vec2 op = u * 2.0;
    op.x += iTime * 0.05;
    c = mix(c, txc(c0, 0.98, vec2(2.5, 2.5)), smoothstep(b * 5.0, -b * 5.0, GRND5));

    op = vec2(u.x * 3.0 + iTime * 0.1 - shadow_pos, u.y * 3.0 - 0.5);
    c = mix(c, c * 0.75, smoothstep(b * 30.0, -b * 30.0, GRND4));
    op.x += shadow_pos;
    c = mix(c, txc(c1, 0.98, vec2(1.33, 1.33)), smoothstep(b * 3.0, -b * 3.0, GRND4));

    op = vec2(u.x * 4.0 + iTime * 0.2 - shadow_pos, u.y * 3.0 - 0.2);
    c = mix(c, c * 0.9, smoothstep(b * 10.0, -b * 10.0, GRND3));
    op.x += shadow_pos;
    c = mix(c, txc(c2, 0.98, vec2(0.75, 1.0)), smoothstep(b * 0.5, -b * 0.5, GRND3));

    op = vec2(u.x * 5.0 + iTime * 0.4 - shadow_pos, u.y * 2.0);
    c = mix(c, c * 0.82, smoothstep(b * 20.0, -b * 20.0, GRND2));
    op.x += shadow_pos;
    c = mix(c, txc(c3, 0.98, vec2(0.4, 1.0)), smoothstep(b * 3.0, -b * 3.0, GRND2));

    op = vec2(u.x * 8.0 + iTime - shadow_pos, u.y * 2.0 + 0.02);
    c = mix(c, c * 0.75, smoothstep(b * 30.0, -b * 30.0, GRND1));
    op += vec2(shadow_pos, -0.02);
    c = mix(c, txc(c4, 0.96, vec2(0.5, 1.0)), smoothstep(b * 5.0, -b * 5.0, GRND1));
  }
  return c;
}

// https://iquilezles.org/articles/distfunctions2d
float sdLine(in vec2 p, in vec2 a, in vec2 b) {
  vec2 pa = p - a, ba = b - a;
  float h = clamp(dot(pa, ba) / dot(ba, ba), 0.0, 1.0);
  return length(pa - ba * h);
}

vec3 cloud(in vec2 u, in vec2 p, in float iscale, in vec3 c, const in vec3 cloud_color, in vec2 shadow_pos, in float shadow_factor, in float blur, in float shadow_blur) {
  u *= iscale;
  p *= iscale;

    // thread shadow
  c = mix(c, c * .95, smoothstep(shadow_blur * 0.2, -shadow_blur * 0.2, sdLine(u, p + vec2(shadow_pos.x, 0.07), vec2(p.x + shadow_pos.x, iscale))));

    // cloud shadow
  vec2 st = u - p - shadow_pos;
  float d = length(st) - 0.07;
  d = min(d, length((st - vec2(0.06, 0))) - 0.055);
  d = min(d, length((st + vec2(0.06, 0))) - 0.055);
  c = mix(c, c * shadow_factor, smoothstep(shadow_blur, -shadow_blur, d));

    // cloud
  st += shadow_pos;
  d = length(st) - 0.07;
  d = min(d, length((st - vec2(0.06, 0))) - 0.055);
  d = min(d, length((st + vec2(0.06, 0))) - 0.055);
  vec2 op = st;
  c = mix(c, cloud_color * 0.98 + (1.0 - 0.98) * texture(iChannel0, st * 2.5).r, smoothstep(blur, -blur, d));

    // thread
  c = mix(c, cloud_color * 0.65, smoothstep(blur / (iscale * iscale), -(blur * 0.5) / (iscale * iscale), sdLine(u, p + vec2(0, 0.065), vec2(p.x, iscale))));
  return c;
}

const float DONT_CARE = 1000.0;

struct CloudConfig {
  float x0;
  float xphase;
  float xvf;
    // float px; // todo: remove
  float vx;
  float y0, yamp, yphase, yvf;
};

CloudConfig[10] cca =  CloudConfig[10](
  CloudConfig(1.4, 50.0, 0.005, 1.5, 0.8, 0.0, DONT_CARE, DONT_CARE),
  CloudConfig(1.4, 0.0, 0.0055, 1.5, 0.75, 0.01, 0.0, 0.1),
  CloudConfig(1.4, 100.0, 0.0045, 1.5, 0.8, 0.02, 0.5, 0.01),
  CloudConfig(1.4, 0.75, 0.0045, 1.5, 0.88, 0.03, 0.75, 0.01),
  CloudConfig(1.41, 75.0, 0.007, 1.5, 0.88, 0.01, 0.0, 0.05),
  CloudConfig(1.41, 50.0, 0.0071, 1.5, 0.85, 0.0095, 0.5, 0.042),
  CloudConfig(1.41, 35.0, 0.0067, 1.5, 0.82, 0.012, 0.9, 0.035),
  CloudConfig(1.50, 0.0, 0.011, 1.75, 0.85, 0.025, 0.0, 0.2),
  CloudConfig(1.50, 50.0, 0.01, 1.75, 0.85, 0.0125, 1.5, 0.08),
  CloudConfig(1.50, 35.0, 0.009, 1.75, 0.8, 0.025, 0.5, 0.05)
);

CloudConfig np_cloud_cc(int num1) {
  if(num1 - 1 >= 0 && num1 - 1 <= 9) {
    return cca[num1 - 1];
  }
  CloudConfig cc0 = CloudConfig(DONT_CARE, DONT_CARE, DONT_CARE, DONT_CARE, DONT_CARE, DONT_CARE, DONT_CARE, DONT_CARE);
  return cc0;
}

vec2 np_cloud2(float t, CloudConfig cc) {

  float px = (t + cc.xphase) * cc.xvf;
  float y = cc.y0 + sin(cc.yphase + t * cc.yvf) * cc.yamp;
  float x = cc.x0 - fract(px) * cc.vx;

  vec2 np = vec2(x, y); // x : -1 1

  return np;
}
vec2 np_cloud(float t, int num) {
  CloudConfig cc = np_cloud_cc(num);

  return np_cloud2(t, cc);
}

struct CloudBConf {
  int indx1;
  vec2 uv;
  vec2 p;
  float iscale;
  vec3 c;
  vec3 cloud_color;
  float shadow_pos1;
  float shadow_factor;
  float blur;
  float shadow_blur;
};
vec3 cloud1(int idx, CloudBConf cc, vec2 shadow_pos) {
  if (idx != cc.indx1) {
    return vec3(DONT_CARE, DONT_CARE, DONT_CARE);
  }
  return cloud(cc.uv, cc.p, cc.iscale, cc.c, cc.cloud_color, cc.shadow_pos1 * shadow_pos, cc.shadow_factor, cc.blur, cc.shadow_blur);
}

vec3 clouds(vec3 c, float iTime, vec2 uv, float shadow_pos) {

  CloudBConf[11] ccb;
  vec2 np;
    // 1

  np = np_cloud(iTime, 1);

  // 👮 todo: now move np out of this:
  ccb[1]=CloudBConf(1,uv, np, 2.0, c, c7,  1.0 * 0.2, 0.8, 0.01, 0.03);

  c = cloud1(1,ccb[1], vec2(shadow_pos, -0.1));

    // 2
  np = np_cloud(iTime, 2);
  ccb[2]=CloudBConf(2,uv, np, 2.0, c, c7, 1.0 * 0.2, 0.8, 0.01, 0.03);
  c = cloud1(2,ccb[2] , vec2(shadow_pos, -0.1));

    // 3
  np = np_cloud(iTime, 3);
  ccb[3]=CloudBConf(3,uv, np, 2.0, c, c7, 1.0 * 0.2, 0.8, 0.01, 0.03);
  c = cloud1(3,ccb[3] , vec2(shadow_pos, -0.1));

    // 4
  np = np_cloud(iTime, 4);
  ccb[4]=CloudBConf(4,uv, np, 2.0, c, c7, 1.0 * 0.2, 0.8, 0.01, 0.03);
  c = cloud1(4,ccb[4] , vec2(shadow_pos, -0.1));

    // 5
  np = np_cloud(iTime, 5);
  ccb[5]=CloudBConf(5,uv, np, 1.5, c, c6, 1.0 * 0.2, 0.8, 0.005, 0.04);
  c = cloud1(5,ccb[5] , vec2(shadow_pos, -0.1));

    // 6
  np = np_cloud(iTime, 6);
  ccb[6]=CloudBConf(6,uv, np, 1.5, c, c6, 1.0 * 0.2, 0.8, 0.005, 0.04);
  c = cloud1(6,ccb[6] , vec2(shadow_pos, -0.1));

  np = np_cloud(iTime, 7);
   ccb[7]=CloudBConf(7,uv, np, 1.5, c, c6, 1.0 * 0.2, 0.8, 0.005, 0.04);
  c = cloud1(7,ccb[7], vec2(shadow_pos, -0.1));

  np = np_cloud(iTime, 8);
  ccb[8]=CloudBConf(8,uv, np, 1.0, c, c5, 1.0 * 0.2, 0.8, 0.002, 0.04);
  c = cloud1(8,ccb[8] , vec2(shadow_pos, -0.1));

  np = np_cloud(iTime, 9);
  ccb[9]=CloudBConf(9,uv, np, 1.0, c, c5, 1.0 * 0.2, 0.8, 0.002, 0.04);
  c = cloud1(9,ccb[9] , vec2(shadow_pos, -0.1));

  np = np_cloud(iTime, 10);
  ccb[10]=CloudBConf(10,uv, np, 1.0, c, c5, 1.0 * 0.2, 0.8, 0.002, 0.04);
  c = cloud1(10,ccb[10] , vec2(shadow_pos, -0.1));

  return c;
}
vec3 mainImage1(out vec4 fragColor, in vec2 fragCoord) {
  vec2 uv = fragCoord / iResolution.xy;
  uv.x *= 4.0 / 3.0; // dev in 4/3 screen

    // beautiful sky
  float d = length(uv - vec2(0.25, 0.5)); // -0.5;
  vec3 c = mix(vec3(.4, 0.4, .8), vec3(0.55, 0.8, 0.8), smoothstep(1.7, 0., d));

    // gorgeous ground
  float shadow_pos = -smoothstep(1.0, 0.0, uv.x) * 0.06 - 0.1;
  c = ground(uv, c, shadow_pos);

    // wonderful clouds
  c = clouds(c, iTime, uv, shadow_pos);
  return c;
}
void mainImage(out vec4 fragColor, in vec2 fragCoord) {
  vec3 c3 = mainImage1(fragColor, fragCoord);
  fragColor = vec4(c3, 1.0);
}

/*
Precedence:
https://www.shadertoy.com/view/WtjGRc
Paper scroll.
Made with paper, scissors and a little thread.
Soundcloud music : Jamal Green - Equilinox game music
Tags: 2d, paper, cutting
Created by Ping2_0 in 2019-06-14
*/