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. 27 struct 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. 42 class b2Shape 43 { 44 public: 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 96 inline b2Shape::Type b2Shape::GetType() const 97 { 98 return m_type; 99 } 100 101 #endif 102
