shader_type canvas_item;

uniform float shake_intensity = 0.0;
uniform float shake_speed = 20.0;

void vertex()
{
	vec2 shake = vec2(0.0);

	if (VERTEX.y < 0.0)
	{
		shake.x = sin(TIME * shake_speed + VERTEX.y) * shake_intensity;
	}

	VERTEX.xy += shake;
}