Smoothstep but less continuous

notsosmoothstep.h

float notsosmoothstep(float x, float edge0, float edge1) {
	x = (x - edge0) / (edge1 - edge0); // [edge0, edge1] -> [0, 1]

	x = x < 0.0 ? 0.0 : x; // max(x, 0)
	x = x > 1.0 ? 1.0 : x; // min(x, 1)

	x -= 0.5;

	return 2.0*(-x*abs(x)+x)-0.5;
}