132 lines
3.6 KiB
C++
132 lines
3.6 KiB
C++
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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/** \file
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* \ingroup imbdds
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*/
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/*
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* This file is based on a similar file from the NVIDIA texture tools
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* (http://nvidia-texture-tools.googlecode.com/)
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*
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* Original license from NVIDIA follows.
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*/
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/* Copyright NVIDIA Corporation 2007 -- Ignacio Castano <icastano@nvidia.com>
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following
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* conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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#pragma once
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#include "Common.h"
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namespace PixelFormat {
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/** Convert component \a c having \a inbits to the returned value having \a outbits. */
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inline uint convert(uint c, uint inbits, uint outbits)
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{
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if (inbits == 0) {
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return 0;
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}
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else if (inbits >= outbits) {
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/* truncate */
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return c >> (inbits - outbits);
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}
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else {
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/* bitexpand */
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return (c << (outbits - inbits)) | convert(c, inbits, outbits - inbits);
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}
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}
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/* Get pixel component shift and size given its mask. */
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inline void maskShiftAndSize(uint mask, uint *shift, uint *size)
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{
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if (!mask) {
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*shift = 0;
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*size = 0;
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return;
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}
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*shift = 0;
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while ((mask & 1) == 0) {
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++(*shift);
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mask >>= 1;
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}
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*size = 0;
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while ((mask & 1) == 1) {
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++(*size);
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mask >>= 1;
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}
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}
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inline float quantizeCeil(float f, int inbits, int outbits)
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{
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#if 0
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uint i = f * (float(1 << inbits) - 1);
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i = convert(i, inbits, outbits);
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float result = float(i) / (float(1 << outbits) - 1);
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nvCheck(result >= f);
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#endif
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float result;
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int offset = 0;
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do {
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uint i = offset + uint(f * (float(1 << inbits) - 1));
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i = convert(i, inbits, outbits);
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result = float(i) / (float(1 << outbits) - 1);
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offset++;
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} while (result < f);
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return result;
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}
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#if 0
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inline float quantizeRound(float f, int bits)
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{
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float scale = float(1 << bits);
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return fround(f * scale) / scale;
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}
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inline float quantizeFloor(float f, int bits)
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{
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float scale = float(1 << bits);
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return floor(f * scale) / scale;
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}
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#endif
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} /* namespace PixelFormat */
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