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_POLYGON_SHAPE_H 20 #define B2_POLYGON_SHAPE_H 21 22 #include <Box2D/Collision/Shapes/b2Shape.h> 23 24 /// A convex polygon. It is assumed that the interior of the polygon is to 25 /// the left of each edge. 26 /// Polygons have a maximum number of vertices equal to b2_maxPolygonVertices. 27 /// In most cases you should not need many vertices for a convex polygon. 28 class b2PolygonShape : public b2Shape 29 { 30 public: 31 b2PolygonShape(); 32 33 /// Implement b2Shape. 34 b2Shape* Clone(b2BlockAllocator* allocator) const; 35 36 /// @see b2Shape::GetChildCount 37 int32 GetChildCount() const; 38 39 /// Create a convex hull from the given array of local points. 40 /// The count must be in the range [3, b2_maxPolygonVertices]. 41 /// @warning the points may be re-ordered, even if they form a convex polygon 42 /// @warning collinear points are handled but not removed. Collinear points 43 /// may lead to poor stacking behavior. 44 void Set(const b2Vec2* points, int32 count); 45 46 /// Build vertices to represent an axis-aligned box centered on the local origin. 47 /// @param hx the half-width. 48 /// @param hy the half-height. 49 void SetAsBox(float32 hx, float32 hy); 50 51 /// Build vertices to represent an oriented box. 52 /// @param hx the half-width. 53 /// @param hy the half-height. 54 /// @param center the center of the box in local coordinates. 55 /// @param angle the rotation of the box in local coordinates. 56 void SetAsBox(float32 hx, float32 hy, const b2Vec2& center, float32 angle); 57 58 /// @see b2Shape::TestPoint 59 bool TestPoint(const b2Transform& transform, const b2Vec2& p) const; 60 61 /// Implement b2Shape. 62 bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input, 63 const b2Transform& transform, int32 childIndex) const; 64 65 /// @see b2Shape::ComputeAABB 66 void ComputeAABB(b2AABB* aabb, const b2Transform& transform, int32 childIndex) const; 67 68 /// @see b2Shape::ComputeMass 69 void ComputeMass(b2MassData* massData, float32 density) const; 70 71 /// Get the vertex count. 72 int32 GetVertexCount() const { return m_count; } 73 74 /// Get a vertex by index. 75 const b2Vec2& GetVertex(int32 index) const; 76 77 /// Validate convexity. This is a very time consuming operation. 78 /// @returns true if valid 79 bool Validate() const; 80 81 b2Vec2 m_centroid; 82 b2Vec2 m_vertices[b2_maxPolygonVertices]; 83 b2Vec2 m_normals[b2_maxPolygonVertices]; 84 int32 m_count; 85 }; 86 87 inline b2PolygonShape::b2PolygonShape() 88 { 89 m_type = e_polygon; 90 m_radius = b2_polygonRadius; 91 m_count = 0; 92 m_centroid.SetZero(); 93 } 94 95 inline const b2Vec2& b2PolygonShape::GetVertex(int32 index) const 96 { 97 b2Assert(0 <= index && index < m_count); 98 return m_vertices[index]; 99 } 100 101 #endif 102
