go_bus_seat_texture.glsl

float angle(vec2 uv) {
    float a = atan(uv.y / uv.x);
    if (uv.x < 0.) {
        a += PI;
   } 
    if (uv.x > 0. && uv.y < 0.) {
        a += PI2;
    }
    return a;
}

vec2 rad2vec(float r) {
    return vec2(cos(r), sin(r));
}

vec2 rotate(vec2 v, float r) {
    //return vec2( v.x * cos(r) + v.y * sin(r), v.y * sin(r) - v.x * cos(r));
    return rotate(vec2(0.), v, r);
}

void main() {
    vec3 c = black;
    vec2 uv_ = uv();
    uv_ += rad2vec(noise(time * 0.1)) * 1.;
    uv_ *= vec2(200., 200.) * 1.5;
    uv_ += rad2vec(noise(uv_ * .5) * PI2) * 0.2;
    uv_ += rad2vec(fbm(uv_, 2) * PI2) * 0.3;
    float v = (cos(uv_.x) + pow(cos(uv_.x - PI/4.), 1.));
    v = v * .25 + 0.5;
    v = v * pow(sin(uv_.y  * .8 + (fbm(uv_.x * .5, 1) - .5) * 4.0 - abs(sin(uv_.x)) * .5) * 1., .4);
    //v = pow(v, 2.);
    v *= 1.;
    c = v * vec3(.8, 0.15, .1);
    gl_FragColor = vec4(c, 1.);
}