uniform float time;         // time in seconds
uniform float speed;        // the speed in the range of 0 - 1
uniform vec2 amplitude;     // amplitude of x and y wave
uniform vec2 waves;     // the number of waves
uniform vec2 texsize;       // size of the texture
uniform sampler2D tex0;     // the texture we apply the shader on

const float pi = 3.14159;

void main(void) {

    // getting the current uv coordinates
    vec2 uv = gl_TexCoord[0].xy;

    // holding a temp vector of the current fragment
    vec2 temp = vec2(uv.x, uv.y);

    float angularFre;

    if(waves.x > 0.0) {
        angularFre = 2.0 * pi * waves.x;
        uv.x += sin(temp.y * angularFre  + (time * (speed * 10.0))) * (amplitude.x / texsize.x) * 10.0;

    }
    if(waves.y > 0.0) {
        angularFre = 2.0 * pi * waves.y;
        uv.y += sin(temp.x * angularFre  + (time * (speed * 10.0))) * (amplitude.y / texsize.y) * 10.0;
    }

    if(uv.x < 0.0 || uv.x > 1.) {
        discard;
    }
    if(uv.y < 0.0 || uv.y > 1.) {
        discard;
    }

    vec4 color = texture2D(tex0, uv);
    gl_FragColor = color;
}