float noise(vec2 p) // magic fract 2 to 1 noise {vec2 ip = floor(p);vec2 u = fract(p);u = u*u*(3.0-2.0*u);float res = mix(mix(rand(ip),rand(ip+vec2(1.0,0.0)),u.x),mix(rand(ip+vec2(0.0,1.0)),rand(ip+vec2(1.0,1.0)),u.x),u.y);return res*res;}