/** * @file llsmoothstep.h * @brief Smoothstep - transition from 0 to 1 - function, first and second derivatives all continuous (smooth) * * $LicenseInfo:firstyear=2001&license=viewerlgpl$ * Second Life Viewer Source Code * Copyright (C) 2010, Linden Research, Inc. * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; * version 2.1 of the License only. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA * * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA * $/LicenseInfo$ */ #ifndef LL_LLSMOOTHSTEP_H #define LL_LLSMOOTHSTEP_H template <class LLDATATYPE> inline LLDATATYPE llsmoothstep(const LLDATATYPE& edge0, const LLDATATYPE& edge1, const LLDATATYPE& value) { if (value < edge0) return (LLDATATYPE)0; if (value >= edge1) return (LLDATATYPE)1; // Scale/bias into [0..1] range LLDATATYPE scaled_value = (value - edge0) / (edge1 - edge0); return scaled_value * scaled_value * (3 - 2 * scaled_value); } #endif // LL_LLSMOOTHSTEP_H