Sweep.hpp
Go to the documentation of this file.
1 /*
2  * Original work Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
3  * Modified work Copyright (c) 2017 Louis Langholtz https://github.com/louis-langholtz/PlayRho
4  *
5  * This software is provided 'as-is', without any express or implied
6  * warranty. In no event will the authors be held liable for any damages
7  * arising from the use of this software.
8  *
9  * Permission is granted to anyone to use this software for any purpose,
10  * including commercial applications, and to alter it and redistribute it
11  * freely, subject to the following restrictions:
12  *
13  * 1. The origin of this software must not be misrepresented; you must not
14  * claim that you wrote the original software. If you use this software
15  * in a product, an acknowledgment in the product documentation would be
16  * appreciated but is not required.
17  * 2. Altered source versions must be plainly marked as such, and must not be
18  * misrepresented as being the original software.
19  * 3. This notice may not be removed or altered from any source distribution.
20  */
21 
22 #ifndef PLAYRHO_COMMON_SWEEP_HPP
23 #define PLAYRHO_COMMON_SWEEP_HPP
24 
25 #include <PlayRho/Common/Position.hpp>
26 #include <PlayRho/Common/Settings.hpp>
27 #include <PlayRho/Common/Vector2.hpp>
28 
29 namespace playrho {
30 namespace d2 {
31 
41 class Sweep
42 {
43 public:
44 
46  Sweep() = default;
47 
49  PLAYRHO_CONSTEXPR inline Sweep(const Sweep& copy) = default;
50 
52  PLAYRHO_CONSTEXPR inline Sweep(const Position p0, const Position p1,
53  const Length2 lc = Length2{0_m, 0_m},
54  Real a0 = 0) noexcept:
55  pos0{p0}, pos1{p1}, localCenter{lc}, alpha0{a0}
56  {
57  assert(a0 >= 0);
58  assert(a0 < 1);
59  }
60 
62  PLAYRHO_CONSTEXPR inline explicit Sweep(const Position p,
63  const Length2 lc = Length2{0_m, 0_m}):
64  Sweep{p, p, lc, 0}
65  {
66  // Intentionally empty.
67  }
68 
72  Length2 GetLocalCenter() const noexcept { return localCenter; }
73 
76  Real GetAlpha0() const noexcept { return alpha0; }
77 
87  void Advance0(Real alpha) noexcept;
88 
91  void ResetAlpha0() noexcept;
92 
94  Position pos0;
95 
97  Position pos1;
98 
99 private:
102  Length2 localCenter = Length2{0_m, 0_m};
103 
108  Real alpha0 = 0;
109 };
110 
111 inline void Sweep::Advance0(const Real alpha) noexcept
112 {
113  assert(IsValid(alpha));
114  assert(alpha >= 0);
115  assert(alpha < 1);
116  assert(alpha0 < 1);
117 
118  const auto beta = (alpha - alpha0) / (1 - alpha0);
119  pos0 = GetPosition(pos0, pos1, beta);
120  alpha0 = alpha;
121 }
122 
123 inline void Sweep::ResetAlpha0() noexcept
124 {
125  alpha0 = 0;
126 }
127 
128 // Free functions...
129 
130 } // namespace d2
131 
134 template <>
135 PLAYRHO_CONSTEXPR inline bool IsValid(const d2::Sweep& value) noexcept
136 {
137  return IsValid(value.pos0) && IsValid(value.pos1)
138  && IsValid(value.GetLocalCenter()) && IsValid(value.GetAlpha0());
139 }
140 
141 } // namespace playrho
142 
143 #endif // PLAYRHO_COMMON_SWEEP_HPP