wobble

void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
    // Normalized pixel coordinates (from 0 to 1)
    vec2 uv = fragCoord/iResolution.xy;
    vec2 m = iMouse.xy/iResolution.xy;
    uv.x *= iResolution.x/iResolution.y;

    m.x *= iResolution.x/iResolution.y;

    float d = smoothstep(0.70, 0.8, 1.-length(uv-m)) * cos(length(uv-m)*40.+iTime);

    // Time varying pixel color
    vec3 col = texture(iChannel0, uv + vec2(d * 0.01)).rgb;

    // Output to screen
    fragColor = vec4(col,1.0);
}