out vec4 FragColor;
uniform sampler2D uTexMain;

in vec2 aUv;

vec2 rand_hash22( vec2 p )
{
   vec3 p3 = fract(vec3(p.xyx) * 213.8976123);
   p3 += dot(p3, p3.yzx+19.19);
   return fract(vec2((p3.x + p3.y)*p3.z, (p3.x+p3.z)*p3.y));
}

void main()
{
   vec2 voffset = rand_hash22( aUv );
   
   float bamt = abs(aUv.x-0.5)*2.0;
   bamt = pow(bamt,4.0)*0.05;

   FragColor = texture( uTexMain, aUv + voffset*bamt );
}