1/* 2* Copyright (c) 2006-2010 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_CHAIN_SHAPE_H 20#define B2_CHAIN_SHAPE_H 21 22#include <Box2D/Collision/Shapes/b2Shape.h> 23 24class b2EdgeShape; 25 26/// A chain shape is a free form sequence of line segments. 27/// The chain has two-sided collision, so you can use inside and outside collision. 28/// Therefore, you may use any winding order. 29/// Since there may be many vertices, they are allocated using b2Alloc. 30/// Connectivity information is used to create smooth collisions. 31/// WARNING: The chain will not collide properly if there are self-intersections. 32class b2ChainShape : public b2Shape 33{ 34public: 35 b2ChainShape(); 36 37 /// The destructor frees the vertices using b2Free. 38 ~b2ChainShape(); 39 40 /// Clear all data. 41 void Clear(); 42 43 /// Create a loop. This automatically adjusts connectivity. 44 /// @param vertices an array of vertices, these are copied 45 /// @param count the vertex count 46 void CreateLoop(const b2Vec2* vertices, int32 count); 47 48 /// Create a chain with isolated end vertices. 49 /// @param vertices an array of vertices, these are copied 50 /// @param count the vertex count 51 void CreateChain(const b2Vec2* vertices, int32 count); 52 53 /// Establish connectivity to a vertex that precedes the first vertex. 54 /// Don't call this for loops. 55 void SetPrevVertex(const b2Vec2& prevVertex); 56 57 /// Establish connectivity to a vertex that follows the last vertex. 58 /// Don't call this for loops. 59 void SetNextVertex(const b2Vec2& nextVertex); 60 61 /// Implement b2Shape. Vertices are cloned using b2Alloc. 62 b2Shape* Clone(b2BlockAllocator* allocator) const; 63 64 /// @see b2Shape::GetChildCount 65 int32 GetChildCount() const; 66 67 /// Get a child edge. 68 void GetChildEdge(b2EdgeShape* edge, int32 index) const; 69 70 /// This always return false. 71 /// @see b2Shape::TestPoint 72 bool TestPoint(const b2Transform& transform, const b2Vec2& p) const; 73 74 /// Implement b2Shape. 75 bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input, 76 const b2Transform& transform, int32 childIndex) const; 77 78 /// @see b2Shape::ComputeAABB 79 void ComputeAABB(b2AABB* aabb, const b2Transform& transform, int32 childIndex) const; 80 81 /// Chains have zero mass. 82 /// @see b2Shape::ComputeMass 83 void ComputeMass(b2MassData* massData, float32 density) const; 84 85 /// Get the number of vertices. 86 int32 GetVertexCount() const { return m_count; } 87 88 /// Get the vertices (read-only). 89 const b2Vec2& GetVertex(int32 index) const 90 { 91 b2Assert(0 <= index && index < m_count); 92 return m_vertices[index]; 93 } 94 95 /// Get the vertices (read-only). 96 const b2Vec2* GetVertices() const { return m_vertices; } 97 98 /// The vertices. Owned by this class. 99 b2Vec2* m_vertices; 100 101 /// The vertex count. 102 int32 m_count; 103 104 b2Vec2 m_prevVertex, m_nextVertex; 105 bool m_hasPrevVertex, m_hasNextVertex; 106}; 107 108inline b2ChainShape::b2ChainShape() 109{ 110 m_type = e_chain; 111 m_radius = b2_polygonRadius; 112 m_vertices = NULL; 113 m_count = 0; 114 m_hasPrevVertex = false; 115 m_hasNextVertex = false; 116} 117 118#endif 119