// Plasma 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_scale;
uniform float param_stretch_x;
uniform float param_stretch_y;
uniform float param_distance;
uniform float param_phase;
uniform float param_speed;
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);
}

void main()
{
    vec2 p = (v_uv - 0.5) * param_scale;
    p.x *= param_stretch_x;
    p.y *= param_stretch_y;
    float t = u_time_seconds * param_speed + param_phase;
    float terms = clamp(u_quality_samples, 1.0, 8.0);
    float v = 0.0;
    for (int i = 0; i < 8; i++)
    {
        if (float(i) >= terms) { break; }
        float fi = float(i + 1);
        v += sin(p.x * fi + t * fi * 0.5 + param_seed)
           * sin(p.y * fi * 1.3 - t * fi * 0.3 + param_seed * 2.0);
        v += sin(length(p) * fi * 0.7 + t * 0.8 + param_seed);
    }
    v /= terms;
    v = v * 0.5 + 0.5;
    float d = length(p) * param_distance;
    v += 0.5 + 0.5 * sin(d * 3.0 - t * 1.5 + param_seed);
    v = clamp(v, 0.0, 1.0);
    vec3 col = mix(param_color_a.rgb, param_color_b.rgb, v);
    gl_FragColor = vec4(col * u_layer_opacity, u_layer_opacity);
}