1 /* $Id: fixed.h,v 1.2 2000/10/27 15:21:40 mholst Exp $ */ 2 3 /* 4 * Mesa 3-D graphics library 5 * Version: 2.0 6 * Copyright (C) 1995-1996 Brian Paul 7 * 8 * This library is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Library General Public 10 * License as published by the Free Software Foundation; either 11 * version 2 of the License, or (at your option) any later version. 12 * 13 * This library is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Library General Public License for more details. 17 * 18 * You should have received a copy of the GNU Library General Public 19 * License along with this library; if not, write to the Free 20 * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 21 */ 22 23 #ifndef FIXED_H 24 #define FIXED_H 25 26 27 typedef int GLfixed; 28 29 #define FIXED_ONE 0x00000800 30 #define FIXED_HALF 0x00000400 31 #define FIXED_FRAC_MASK 0x000007FF 32 #define FIXED_INT_MASK (~FIXED_FRAC_MASK) 33 #define FIXED_EPSILON 1 34 #define FIXED_SCALE 2048.0f 35 #define FIXED_SHIFT 11 36 #define FloatToFixed(X) ((GLfixed) ((X) * FIXED_SCALE)) 37 #define IntToFixed(I) ((I) << FIXED_SHIFT) 38 #define FixedToInt(X) ((X) >> FIXED_SHIFT) 39 #define FixedToUns(X) (((unsigned int)(X)) >> 11) 40 #define FixedCeil(X) (((X) + FIXED_ONE - FIXED_EPSILON) & FIXED_INT_MASK) 41 #define FixedFloor(X) ((X) & FIXED_INT_MASK) 42 /* 0.00048828125 = 1/FIXED_SCALE */ 43 #define FixedToFloat(X) ((X) * 0.00048828125f) 44 #define PosFloatToFixed(X) FloatToFixed(X) 45 #define SignedFloatToFixed(X) FloatToFixed(X) 46 47 48 #if DEPTH_BITS==16 49 /* use fixed-point interpolation */ 50 #define FixedToDepth(I) ((I) >> FIXED_SHIFT) 51 #else 52 /* don't really use fixed-point */ 53 #define FixedToDepth(I) (I) 54 #endif 55 56 57 #endif 58