1/*
2* Copyright (c) 2006-2009 Erin Catto http://www.box2d.org
3*
4* This software is provided 'as-is', without any express or implied
5* warranty. In no event will the authors be held liable for any damages
6* arising from the use of this software.
7* Permission is granted to anyone to use this software for any purpose,
8* including commercial applications, and to alter it and redistribute it
9* freely, subject to the following restrictions:
10* 1. The origin of this software must not be misrepresented; you must not
11* claim that you wrote the original software. If you use this software
12* in a product, an acknowledgment in the product documentation would be
13* appreciated but is not required.
14* 2. Altered source versions must be plainly marked as such, and must not be
15* misrepresented as being the original software.
16* 3. This notice may not be removed or altered from any source distribution.
17*/
18
19#ifndef B2_SHAPE_H
20#define B2_SHAPE_H
21
22#include <Box2D/Common/b2BlockAllocator.h>
23#include <Box2D/Common/b2Math.h>
24#include <Box2D/Collision/b2Collision.h>
25
26/// This holds the mass data computed for a shape.
27struct b2MassData
28{
29 /// The mass of the shape, usually in kilograms.
30 float32 mass;
31
32 /// The position of the shape's centroid relative to the shape's origin.
33 b2Vec2 center;
34
35 /// The rotational inertia of the shape about the local origin.
36 float32 I;
37};
38
39/// A shape is used for collision detection. You can create a shape however you like.
40/// Shapes used for simulation in b2World are created automatically when a b2Fixture
41/// is created. Shapes may encapsulate a one or more child shapes.
42class b2Shape
43{
44public:
45
46 enum Type
47 {
48 e_circle = 0,
49 e_edge = 1,
50 e_polygon = 2,
51 e_chain = 3,
52 e_typeCount = 4
53 };
54
55 virtual ~b2Shape() {}
56
57 /// Clone the concrete shape using the provided allocator.
58 virtual b2Shape* Clone(b2BlockAllocator* allocator) const = 0;
59
60 /// Get the type of this shape. You can use this to down cast to the concrete shape.
61 /// @return the shape type.
62 Type GetType() const;
63
64 /// Get the number of child primitives.
65 virtual int32 GetChildCount() const = 0;
66
67 /// Test a point for containment in this shape. This only works for convex shapes.
68 /// @param xf the shape world transform.
69 /// @param p a point in world coordinates.
70 virtual bool TestPoint(const b2Transform& xf, const b2Vec2& p) const = 0;
71
72 /// Cast a ray against a child shape.
73 /// @param output the ray-cast results.
74 /// @param input the ray-cast input parameters.
75 /// @param transform the transform to be applied to the shape.
76 /// @param childIndex the child shape index
77 virtual bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
78 const b2Transform& transform, int32 childIndex) const = 0;
79
80 /// Given a transform, compute the associated axis aligned bounding box for a child shape.
81 /// @param aabb returns the axis aligned box.
82 /// @param xf the world transform of the shape.
83 /// @param childIndex the child shape
84 virtual void ComputeAABB(b2AABB* aabb, const b2Transform& xf, int32 childIndex) const = 0;
85
86 /// Compute the mass properties of this shape using its dimensions and density.
87 /// The inertia tensor is computed about the local origin.
88 /// @param massData returns the mass data for this shape.
89 /// @param density the density in kilograms per meter squared.
90 virtual void ComputeMass(b2MassData* massData, float32 density) const = 0;
91
92 Type m_type;
93 float32 m_radius;
94};
95
96inline b2Shape::Type b2Shape::GetType() const
97{
98 return m_type;
99}
100
101#endif
102