Vector class for Forge. Don't know if we need it, but it helped me to
grok vectors.
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Jeff Teunissen
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f7b0227299
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/*
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Vector.h
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A vector math class supporting up to six dimensions (interface)
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Copyright (C) 2001 Jeff Teunissen <deek@d2dc.net>
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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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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.
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See the GNU General Public License for more details.
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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:
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Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307, USA
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$Id$
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*/
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#include <QF/mathlib.h>
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#import <Foundation/NSObject.h>
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@interface Vector: NSObject <NSCopying>
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{
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unsigned int _numDimensions;
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double _values[6];
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}
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- (id) initWithString: (NSString *) str;
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- (id) initwithNumbers: ...;
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- (id) zero dimensions: (unsigned char) d;
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- (id) one dimensions: (unsigned char) d;
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- (double) x; // Convenience methods for three-dimensional vectors
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- (double) y;
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- (double) z;
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- (double) dimension: (unsigned char) d;
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- (void) setX: (double) val;
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- (void) setY: (double) val;
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- (void) setZ: (double) val;
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- (void) setDimension: (unsigned char) d to: (double) val;
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- (unsigned char) dimensions;
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- (double) length;
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- (double) direction;
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- (void) add: (Vector *) vec;
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- (void) subtract: (Vector *) vec;
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- (void) scale: (double) scalar;
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- (void) invert; // Turn the direction around
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- (void) normalize; // Scale the vector so that its length is 1
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- (void) isEqualToVector: (Vector *) vec;
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- (NSString *) stringValue;
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@end
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Vector *
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CrossProduct (Vector *, Vector *);
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double
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DotProduct (Vector *, Vector *);
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@ -0,0 +1,215 @@
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/*
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Vector.h
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Vector class definition
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Copyright (C) 2001 Jeff Teunissen <deek@d2dc.net>
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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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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.
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See the GNU General Public License for more details.
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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:
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Free Software Foundation, Inc.
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59 Temple Place - Suite 330
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Boston, MA 02111-1307, USA
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$Id$
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*/
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/*
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For more information on vectors, see:
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http://chortle.ccsu.ctstateu.edu/vectorLessons/vectorIndex.html
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Vector formulae: (notation: vN = vector N)
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Addition: vx + vy == (x1+y1, x2+y2, ...)
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Subtraction: vx - vy == (x1-y1, x2-y2, ...) OR vx + (-vy)
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(3, 3) - (2, 1) = (3, 3) + (-2, -1) = (1, 2)
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*/
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#ifdef HAVE_CONFIG_H
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# include <Config.h>
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#endif
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#include <math.h>
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#import <Vector.h>
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@implementation Vector
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- (id) initWithString: (NSString *) str
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{
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}
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- (id) zero dimensions: (unsigned char) d
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{
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_numDimensions = d;
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for (i = 0; i < d; i++)
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_values[i] = 0.0;
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return self;
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}
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- (id) one dimensions: (unsigned char) d
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{
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_numDimensions = d;
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for (i = 0; i < d; i++)
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_values[i] = 1.0;
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return self;
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}
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- (double) x
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{
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if ([self dimensions] < 1) { // Makes no sense, but catch it
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NSLog (@"Not enough dimensions for operation");
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return 0.0;
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}
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return _values[0];
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}
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- (double) y
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{
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if ([self dimensions] < 2) { // Makes no sense, but catch it
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NSLog (@"Not enough dimensions for operation");
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return 0.0;
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}
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return _values[1];
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}
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- (double) z
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{
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if ([self dimensions] < 3) { // This one could happen
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NSLog (@"Not enough dimensions for operation");
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return 0.0;
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}
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return _values[2];
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}
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- (double) dimension: (unsigned char) d
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{
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if (d <= 0) { // deal with calls that don't make any sense
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NSLog (@"Vectors cannot have zero dimensions");
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return 0.0;
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}
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if ([self dimensions] < d) { // This one's easy to make happen
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NSLog (@"Not enough dimensions for operation");
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return 0.0;
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}
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return _values[d - 1];
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}
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- (double) length;
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{
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int i;
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double temp;
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for (i = 1; i <= [self dimensions]; i++)
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temp += sqrt ([self dimension: i] ** 2);
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return sqrt (temp);
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}
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- (void) add: (Vector *) vec
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{
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int i;
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if ([vec dimensions] != [self dimensions])
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NSLog (@"Tried to add unlike vectors");
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for (i = 1; i <= [self dimensions]; i++)
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[self setDimension: i to: [self dimension: i] + [vec dimension: i]];
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}
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/*
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subtract:
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Subtract a vector by adding its inverse
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The temporary object is autoreleased so it will be deallocated when the
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application loop completes
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*/
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- (void) subtract: (Vector *) vec
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{
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[self add: [[[vec copy] autorelease] invert]];
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}
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- (void) scale: (double) scalar
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{
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int i;
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for (i = 0; i < [self dimensions]; i++)
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_values[i - 1] *= scalar;
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}
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/*
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invert
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Turn a vector around. Since vectors have no position, this is OK
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*/
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- (void) invert
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{
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[self scale: -1];
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}
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/*
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Convert to a unit vector (make our length 1.0)
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*/
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- (void) normalize
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{
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[self scale: 1.0 / [self length]];
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}
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@end
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/*
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Get the dot product
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*/
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double
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DotProduct (Vector *x, Vector *y)
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{
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unsigned int i;
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unsigned int d;
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double product = 0.0;
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if ([x dimensions] != [y dimensions]) {
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NSLog (@"Tried to get the dot product of unlike vectors");
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return -1;
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}
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for (i = 1, d = [x dimensions]; i <= d; i++) {
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product += [x dimension: i] * [y dimension: i];
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}
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return product;
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}
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/*
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CrossProduct ()
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Get the cross product
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*/
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Vector *
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CrossProduct (Vector *a, Vector *b)
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{
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Vector *newVec = [[[Vector alloc] zero dimensions: 3] autorelease];
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if (([a dimensions] != 3) || ([b dimensions] != 3)) {
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NSLog (@"Tried to get the cross product of non-3D vectors");
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return (Vector *) nil;
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}
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[newVec setX: ([a y] * [b z]) - ([a z] * [b y])];
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[newVec setY: ([a z] * [b x]) - ([a x] * [b z])];
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[newVec setZ: ([a x] * [b y]) - ([a y] * [b x])];
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}
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