// Slow waves with white foam on the crests

void mainImage(out vec4 fragColor, in vec2 fragCoord) {
    float i = floor(fragCoord.x / iResolution.x * 16.0);

    float w = 0.5 + 0.5 * sin(i * 0.55 - iTime * 0.5);
    float w2 = 0.5 + 0.5 * sin(i * 0.9 + iTime * 0.35 + 1.0);
    float h = 0.6 * w + 0.4 * w2;

    vec3 deep = vec3(0.0, 0.05, 0.28);
    vec3 shallow = vec3(0.0, 0.55, 0.75);
    vec3 col = mix(deep, shallow, h);

    float foam = smoothstep(0.82, 0.97, h);
    col = mix(col, vec3(0.9), foam * 0.8);
    fragColor = vec4(col, 1.0);
}