Panda3D

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particleCommonFuncs.h
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1/**
2 * PANDA 3D SOFTWARE
3 * Copyright (c) Carnegie Mellon University. All rights reserved.
4 *
5 * All use of this software is subject to the terms of the revised BSD
6 * license. You should have received a copy of this license along
7 * with this source code in a file named "LICENSE."
8 *
9 * @file particleCommonFuncs.h
10 * @author darren
11 * @date 2000-10-02
12 */
13
14#ifndef PARTICLECOMMONFUNCS_H
15#define PARTICLECOMMONFUNCS_H
16
17// evaluates to a float in the range [0,1]
18#define NORMALIZED_RAND() ((PN_stdfloat)rand() / (PN_stdfloat)RAND_MAX)
19
20// linear interpolation t is in [0,1] result is in [X0,X1]
21#define LERP(t,X0,X1) ((X0) + ((t) * ((X1) - (X0))))
22
23// linear t -> cubic t t is in [0,1] result is in [0,1]
24#define CUBIC_T(t) ((t)*(t)*(3-(2*(t))))
25
26// cubic interpolation t is in [0,1] result is in [X0,X1]
27#define CLERP(t,X0,X1) LERP(CUBIC_T(t), (X0), (X1))
28
29// spread calculator spread is non-negative spread magnitude result is in
30// [-spread,spread]
31#define SPREAD(magnitude) ((magnitude) - (NORMALIZED_RAND() * 2.0f * (magnitude)))
32
33// integer spread calculator spread is non-negative spread magnitude (integer)
34// result is in [-spread,spread]
35#define I_SPREAD(magnitude) ((magnitude) - ((int)rand() % ((2*(magnitude))+1)))
36
37#endif // PARTICLECOMMONFUNCS_H