// Shapes Generator
// HMS MediaEngine – Generator (GLES, Raspberry Pi). ES 2.0: texture2D, gl_FragColor, Schleifen mit konstanter Höchstgrenze.
#version 100
precision mediump float;

uniform vec2  u_resolution;
uniform float u_time_seconds;
uniform float u_delta_seconds;
uniform float u_frame_index;
uniform float u_layer_opacity;
uniform float u_audio_rms;
uniform float u_audio_peak;
uniform float u_audio_bass;
uniform float u_audio_mid;
uniform float u_audio_treble;
uniform float u_audio_beat;
uniform float4 param_color_a;
uniform float4 param_color_b;
uniform float param_form;
uniform float param_count;
uniform float param_size;
uniform float param_rotation;
uniform float param_distribution;
uniform float param_fill_stroke;
uniform float param_seed;
uniform float u_quality_samples;

varying vec2 v_uv;

float hash21(vec2 p)
{
    p = fract(p * vec2(123.34, 456.21));
    p += dot(p, p + 45.32);
    return fract(p.x * p.y);
}

float sdCircle(vec2 p, float r) { return length(p) - r; }
float sdBox(vec2 p, vec2 b) { vec2 d = abs(p) - b; return length(max(d, 0.0)) + min(max(d.x, d.y), 0.0); }
float sdTri(vec2 p, float s) { p = abs(p); return max(p.x * 0.8660254 + p.y * 0.5, -p.y) - s * 0.5; }
float sdLine(vec2 p, vec2 a, vec2 b) { vec2 pa = p - a; vec2 ba = b - a; float h = clamp(dot(pa, ba) / dot(ba, ba), 0.0, 1.0); return length(pa - ba * h); }
float sdPoly(vec2 p, float r, int n) { float an = 6.2831853 / float(n); float a = atan(p.x, p.y) + 0.5; float b = an * floor(a / an); vec2 q = vec2(cos(b), sin(b)) * dot(vec2(cos(a), sin(a)), vec2(cos(b), sin(b))); return length(p - q * r); }

void main()
{
    vec2 p = v_uv - 0.5;
    float t = u_time_seconds;
    float maxN = clamp(u_quality_samples, 1.0, 64.0);
    float form = floor(param_form + 0.5);
    float distr = floor(param_distribution + 0.5);
    float fill = floor(param_fill_stroke + 0.5);
    float acc = 0.0;
    float colAcc = 0.0;
    for (int i = 0; i < 64; i++)
    {
        if (float(i) >= maxN) { break; }
        vec2 pos;
        if (distr < 0.5)
        {
            float g = ceil(sqrt(maxN));
            float gx = float(i % int(g));
            float gy = floor(float(i) / g);
            pos = (vec2(gx, gy) + 0.5) / g - 0.5;
        }
        else if (distr < 1.5)
        {
            float ang = 6.2831853 * float(i) / maxN;
            pos = 0.35 * vec2(cos(ang), sin(ang));
        }
        else
        {
            pos = vec2(hash21(vec2(float(i) + param_seed, 1.0)), hash21(vec2(float(i) + param_seed, 2.0))) - 0.5;
        }
        vec2 lp = p - pos;
        float cr = cos(param_rotation);
        float sr = sin(param_rotation);
        lp = vec2(cr * lp.x - sr * lp.y, sr * lp.x + cr * lp.y);
        float d;
        if (form < 0.5)      { d = sdCircle(lp, param_size); }
        else if (form < 1.5) { d = sdBox(lp, vec2(param_size, param_size)); }
        else if (form < 2.5) { d = sdTri(lp, param_size); }
        else if (form < 3.5) { d = sdLine(lp, vec2(-param_size, 0.0), vec2(param_size, 0.0)); }
        else                 { d = sdPoly(lp, param_size, 6); }
        float v;
        if (fill < 0.5) { v = 1.0 - smoothstep(0.0, 0.01, d); }
        else            { v = 1.0 - smoothstep(0.0, 0.01, abs(d) - 0.01); }
        acc += v;
        colAcc += v * (float(i) / max(maxN - 1.0, 1.0));
    }
    acc = clamp(acc, 0.0, 1.0);
    float mixT = maxN > 1.0 ? colAcc / max(acc, 1e-5) : 0.0;
    vec3 col = mix(param_color_a.rgb, param_color_b.rgb, mixT);
    gl_FragColor = vec4(col * acc * u_layer_opacity, acc * u_layer_opacity);
}