llquantize.h
上传用户:king477883
上传日期:2021-03-01
资源大小:9553k
文件大小:4k
- /**
- * @file llquantize.h
- * @brief useful routines for quantizing floats to various length ints
- * and back out again
- *
- * $LicenseInfo:firstyear=2001&license=viewergpl$
- *
- * Copyright (c) 2001-2010, Linden Research, Inc.
- *
- * Second Life Viewer Source Code
- * The source code in this file ("Source Code") is provided by Linden Lab
- * to you under the terms of the GNU General Public License, version 2.0
- * ("GPL"), unless you have obtained a separate licensing agreement
- * ("Other License"), formally executed by you and Linden Lab. Terms of
- * the GPL can be found in doc/GPL-license.txt in this distribution, or
- * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
- *
- * There are special exceptions to the terms and conditions of the GPL as
- * it is applied to this Source Code. View the full text of the exception
- * in the file doc/FLOSS-exception.txt in this software distribution, or
- * online at
- * http://secondlifegrid.net/programs/open_source/licensing/flossexception
- *
- * By copying, modifying or distributing this software, you acknowledge
- * that you have read and understood your obligations described above,
- * and agree to abide by those obligations.
- *
- * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
- * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
- * COMPLETENESS OR PERFORMANCE.
- * $/LicenseInfo$
- */
- #ifndef LL_LLQUANTIZE_H
- #define LL_LLQUANTIZE_H
- const U16 U16MAX = 65535;
- const F32 OOU16MAX = 1.f/(F32)(U16MAX);
- const U8 U8MAX = 255;
- const F32 OOU8MAX = 1.f/(F32)(U8MAX);
- const U8 FIRSTVALIDCHAR = 54;
- const U8 MAXSTRINGVAL = U8MAX - FIRSTVALIDCHAR; //we don't allow newline or null
- inline U16 F32_to_U16_ROUND(F32 val, F32 lower, F32 upper)
- {
- val = llclamp(val, lower, upper);
- // make sure that the value is positive and normalized to <0, 1>
- val -= lower;
- val /= (upper - lower);
- // round the value. Sreturn the U16
- return (U16)(llround(val*U16MAX));
- }
- inline U16 F32_to_U16(F32 val, F32 lower, F32 upper)
- {
- val = llclamp(val, lower, upper);
- // make sure that the value is positive and normalized to <0, 1>
- val -= lower;
- val /= (upper - lower);
- // return the U16
- return (U16)(llfloor(val*U16MAX));
- }
- inline F32 U16_to_F32(U16 ival, F32 lower, F32 upper)
- {
- F32 val = ival*OOU16MAX;
- F32 delta = (upper - lower);
- val *= delta;
- val += lower;
- F32 max_error = delta*OOU16MAX;
- // make sure that zero's come through as zero
- if (fabsf(val) < max_error)
- val = 0.f;
- return val;
- }
- inline U8 F32_to_U8_ROUND(F32 val, F32 lower, F32 upper)
- {
- val = llclamp(val, lower, upper);
- // make sure that the value is positive and normalized to <0, 1>
- val -= lower;
- val /= (upper - lower);
- // return the rounded U8
- return (U8)(llround(val*U8MAX));
- }
- inline U8 F32_to_U8(F32 val, F32 lower, F32 upper)
- {
- val = llclamp(val, lower, upper);
- // make sure that the value is positive and normalized to <0, 1>
- val -= lower;
- val /= (upper - lower);
- // return the U8
- return (U8)(llfloor(val*U8MAX));
- }
- inline F32 U8_to_F32(U8 ival, F32 lower, F32 upper)
- {
- F32 val = ival*OOU8MAX;
- F32 delta = (upper - lower);
- val *= delta;
- val += lower;
- F32 max_error = delta*OOU8MAX;
- // make sure that zero's come through as zero
- if (fabsf(val) < max_error)
- val = 0.f;
- return val;
- }
- inline U8 F32_TO_STRING(F32 val, F32 lower, F32 upper)
- {
- val = llclamp(val, lower, upper); //[lower, upper]
- // make sure that the value is positive and normalized to <0, 1>
- val -= lower; //[0, upper-lower]
- val /= (upper - lower); //[0,1]
- val = val * MAXSTRINGVAL; //[0, MAXSTRINGVAL]
- val = floor(val + 0.5f); //[0, MAXSTRINGVAL]
- U8 stringVal = (U8)(val) + FIRSTVALIDCHAR; //[FIRSTVALIDCHAR, MAXSTRINGVAL + FIRSTVALIDCHAR]
- return stringVal;
- }
- inline F32 STRING_TO_F32(U8 ival, F32 lower, F32 upper)
- {
- // remove empty space left for NULL, newline, etc.
- ival -= FIRSTVALIDCHAR; //[0, MAXSTRINGVAL]
- F32 val = (F32)ival * (1.f / (F32)MAXSTRINGVAL); //[0, 1]
- F32 delta = (upper - lower);
- val *= delta; //[0, upper - lower]
- val += lower; //[lower, upper]
- return val;
- }
- #endif