File indexing completed on 2025-08-03 03:49:55

0001 /*
0002 * Copyright (c) 2006-2009 Erin Catto http://www.gphysics.com
0003 *
0004 * This software is provided 'as-is', without any express or implied
0005 * warranty.  In no event will the authors be held liable for any damages
0006 * arising from the use of this software.
0007 * Permission is granted to anyone to use this software for any purpose,
0008 * including commercial applications, and to alter it and redistribute it
0009 * freely, subject to the following restrictions:
0010 * 1. The origin of this software must not be misrepresented; you must not
0011 * claim that you wrote the original software. If you use this software
0012 * in a product, an acknowledgment in the product documentation would be
0013 * appreciated but is not required.
0014 * 2. Altered source versions must be plainly marked as such, and must not be
0015 * misrepresented as being the original software.
0016 * 3. This notice may not be removed or altered from any source distribution.
0017 */
0018 
0019 #ifndef B2_POLYGON_SHAPE_H
0020 #define B2_POLYGON_SHAPE_H
0021 
0022 #include <Box2D/Collision/Shapes/b2Shape.h>
0023 
0024 /// A convex polygon. It is assumed that the interior of the polygon is to
0025 /// the left of each edge.
0026 /// Polygons have a maximum number of vertices equal to b2_maxPolygonVertices.
0027 /// In most cases you should not need many vertices for a convex polygon.
0028 class b2PolygonShape : public b2Shape
0029 {
0030 public:
0031     b2PolygonShape();
0032 
0033     /// Implement b2Shape.
0034     b2Shape* Clone(b2BlockAllocator* allocator) const override;
0035 
0036     /// @see b2Shape::GetChildCount
0037     int32 GetChildCount() const override;
0038 
0039     /// Copy vertices. This assumes the vertices define a convex polygon.
0040     /// It is assumed that the exterior is the the right of each edge.
0041     /// The count must be in the range [3, b2_maxPolygonVertices].
0042     void Set(const b2Vec2* vertices, int32 vertexCount);
0043 
0044     /// Build vertices to represent an axis-aligned box.
0045     /// @param hx the half-width.
0046     /// @param hy the half-height.
0047     void SetAsBox(qreal hx, qreal hy);
0048 
0049     /// Build vertices to represent an oriented box.
0050     /// @param hx the half-width.
0051     /// @param hy the half-height.
0052     /// @param center the center of the box in local coordinates.
0053     /// @param angle the rotation of the box in local coordinates.
0054     void SetAsBox(qreal hx, qreal hy, const b2Vec2& center, qreal angle);
0055 
0056     /// @see b2Shape::TestPoint
0057     bool TestPoint(const b2Transform& transform, const b2Vec2& p) const override;
0058 
0059     /// Implement b2Shape.
0060     bool RayCast(b2RayCastOutput* output, const b2RayCastInput& input,
0061                     const b2Transform& transform, int32 childIndex) const override;
0062 
0063     /// @see b2Shape::ComputeAABB
0064     void ComputeAABB(b2AABB* aabb, const b2Transform& transform, int32 childIndex) const override;
0065 
0066     /// @see b2Shape::ComputeMass
0067     void ComputeMass(b2MassData* massData, qreal density) const override;
0068 
0069     /// Get the vertex count.
0070     int32 GetVertexCount() const { return m_vertexCount; }
0071 
0072     /// Get a vertex by index.
0073     const b2Vec2& GetVertex(int32 index) const;
0074 
0075     b2Vec2 m_centroid;
0076     b2Vec2 m_vertices[b2_maxPolygonVertices];
0077     b2Vec2 m_normals[b2_maxPolygonVertices];
0078     int32 m_vertexCount;
0079 };
0080 
0081 inline b2PolygonShape::b2PolygonShape()
0082 {
0083     m_type = e_polygon;
0084     m_radius = b2_polygonRadius;
0085     m_vertexCount = 0;
0086     m_centroid.SetZero();
0087 }
0088 
0089 inline const b2Vec2& b2PolygonShape::GetVertex(int32 index) const
0090 {
0091     b2Assert(0 <= index && index < m_vertexCount);
0092     return m_vertices[index];
0093 }
0094 
0095 #endif