#version 430

in vec4 vPosition;
in vec2 vCoords;
uniform float time;

const float INVERSE_MAX_UINT = 1.0 / 4294967295.0;

float rand(uint seed, float range)
{
    uint i = (seed ^ 12345391u) * 2654435769u;
    i ^= (i << 6u) ^ (i >> 26u);
    i *= 2654435769u;
    i += (i << 5u) ^ (i >> 12u);
    return float(range * i) * INVERSE_MAX_UINT;
}

float ra(uint seed)
{
    return rand(seed++, 2) - 1;
}
void main()
{
    float t = time * 100;

    if(int(t) % 100 == 2)
        t = pow(t,2);

    t = t / 100;

    int tess = 100;
    uint   seed = uint(tess*cos(vCoords.x) + tess*tan(vCoords.y));
    seed = seed * uint(tess*sin(vCoords.x) + tess*tan(vCoords.y));
    seed = seed + uint(sin(t));

    // Initialise
    vec3 outRGB = vec3(1);

    // Target
    vec3 target = vec3(sin(t*vCoords.x*10), 0, cos(t*vCoords.y*10));

    // Watchdogs like background
    target = target + (ra(seed++) / length(vCoords));

    float dist = length(target - vPosition.xyz);

    // Almost a smoke-like effect
    dist = dist - sin(seed - t);

    // Colouring
    outRGB = outRGB * vec3(0.1, 1.0, 1.0) * 1-dist;

    gl_FragColor = vec4(outRGB,0.5);
}