reactphysics3d/src/collision/shapes/TriangleShape.h

/********************************************************************************
* ReactPhysics3D physics library, http://www.reactphysics3d.com                 *
* Copyright (c) 2010-2015 Daniel Chappuis                                       *
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#ifndef REACTPHYSICS3D_TRIANGLE_SHAPE_H
#define REACTPHYSICS3D_TRIANGLE_SHAPE_H

// Libraries
#include "mathematics/mathematics.h"
#include "ConvexShape.h"

/// ReactPhysics3D namespace
namespace reactphysics3d {

// Class TriangleShape
/**
 * This class represents a triangle collision shape that is centered
 * at the origin and defined three points.
 */
class TriangleShape : public ConvexShape {

    protected:

        // -------------------- Attribute -------------------- //

        /// Three points of the triangle
        Vector3 mPoints[3];

        // -------------------- Methods -------------------- //

        /// Private copy-constructor
        TriangleShape(const TriangleShape& shape);

        /// Private assignment operator
        TriangleShape& operator=(const TriangleShape& shape);

        /// Return a local support point in a given direction with the object margin
        virtual Vector3 getLocalSupportPointWithMargin(const Vector3& direction,
                                                       void** cachedCollisionData) const;

        /// Return a local support point in a given direction without the object margin
        virtual Vector3 getLocalSupportPointWithoutMargin(const Vector3& direction,
                                                          void** cachedCollisionData) const;

        /// Return true if a point is inside the collision shape
        virtual bool testPointInside(const Vector3& localPoint, ProxyShape* proxyShape) const;

        /// Raycast method with feedback information
        virtual bool raycast(const Ray& ray, RaycastInfo& raycastInfo, ProxyShape* proxyShape) const;

        /// Allocate and return a copy of the object
        virtual TriangleShape* clone(void* allocatedMemory) const;

        /// Return the number of bytes used by the collision shape
        virtual size_t getSizeInBytes() const;

    public:

        // -------------------- Methods -------------------- //

        /// Constructor
        TriangleShape(const Vector3& point1, const Vector3& point2,
                      const Vector3& point3, decimal margin);

        /// Destructor
        virtual ~TriangleShape();

        /// Return the local bounds of the shape in x, y and z directions.
        virtual void getLocalBounds(Vector3& min, Vector3& max) const;

        /// Return the local inertia tensor of the collision shape
        virtual void computeLocalInertiaTensor(Matrix3x3& tensor, decimal mass) const;

        /// Update the AABB of a body using its collision shape
        virtual void computeAABB(AABB& aabb, const Transform& transform);

        /// Test equality between two triangle shapes
        virtual bool isEqualTo(const CollisionShape& otherCollisionShape) const;
};

// Allocate and return a copy of the object
inline TriangleShape* TriangleShape::clone(void* allocatedMemory) const {
    return new (allocatedMemory) TriangleShape(*this);
}

// Return the number of bytes used by the collision shape
inline size_t TriangleShape::getSizeInBytes() const {
    return sizeof(TriangleShape);
}

// Return a local support point in a given direction with the object margin
inline Vector3 TriangleShape::getLocalSupportPointWithMargin(const Vector3& direction,
                                                           void** cachedCollisionData) const {

    // TODO : Do we need to use margin for triangle support point ?

    return getLocalSupportPointWithoutMargin(direction, cachedCollisionData);
}

// Return a local support point in a given direction without the object margin
inline Vector3 TriangleShape::getLocalSupportPointWithoutMargin(const Vector3& direction,
                                                              void** cachedCollisionData) const {
    Vector3 dotProducts(direction.dot(mPoints[0]), direction.dot(mPoints[1]), direction.dot(mPoints[2]));
    return mPoints[dotProducts.getMaxAxis()];
}

// Return the local bounds of the shape in x, y and z directions.
// This method is used to compute the AABB of the box
/**
 * @param min The minimum bounds of the shape in local-space coordinates
 * @param max The maximum bounds of the shape in local-space coordinates
 */
inline void TriangleShape::getLocalBounds(Vector3& min, Vector3& max) const {

    const Vector3 xAxis(worldPoint1.X, worldPoint2.X, worldPoint3.X);
    const Vector3 yAxis(worldPoint1.Y, worldPoint2.Y, worldPoint3.Y);
    const Vector3 zAxis(worldPoint1.Z, worldPoint2.Z, worldPoint3.Z);
    min.setAllValues(xAxis.getMinValue(), yAxis.getMinValue(), zAxis.getMinValue());
    max.setAllValues(xAxis.getMaxValue(), yAxis.getMaxValue(), zAxis.getMaxValue());
}

// Return the local inertia tensor of the triangle shape
/**
 * @param[out] tensor The 3x3 inertia tensor matrix of the shape in local-space
 *                    coordinates
 * @param mass Mass to use to compute the inertia tensor of the collision shape
 */
inline void TriangleShape::computeLocalInertiaTensor(Matrix3x3& tensor, decimal mass) const {
    tensor.setToZero();
}

// Update the AABB of a body using its collision shape
/**
 * @param[out] aabb The axis-aligned bounding box (AABB) of the collision shape
 *                  computed in world-space coordinates
 * @param transform Transform used to compute the AABB of the collision shape
 */
inline void TriangleShape::computeAABB(AABB& aabb, const Transform& transform) {

    const Vector3 worldPoint1 = transform * mPoints[0];
    const Vector3 worldPoint2 = transform * mPoints[1];
    const Vector3 worldPoint3 = transform * mPoints[2];

    const Vector3 xAxis(worldPoint1.X, worldPoint2.X, worldPoint3.X);
    const Vector3 yAxis(worldPoint1.Y, worldPoint2.Y, worldPoint3.Y);
    const Vector3 zAxis(worldPoint1.Z, worldPoint2.Z, worldPoint3.Z);
    aabb.setMin(Vector3(xAxis.getMinValue(), yAxis.getMinValue(), zAxis.getMinValue()));
    aabb.setMax(Vector3(xAxis.getMaxValue(), yAxis.getMaxValue(), zAxis.getMaxValue()));
}

// Test equality between two triangle shapes
inline bool TriangleShape::isEqualTo(const CollisionShape& otherCollisionShape) const {

    if (!ConvexShape::isEqualTo(otherCollisionShape)) return false;

    const TriangleShape& otherShape = dynamic_cast<const TriangleShape&>(otherCollisionShape);
    return (mPoints[0] == otherShape.mPoints[0] &&
            mPoints[1] == otherShape.mPoints[1] &&
            mPoints[2] == otherShape.mPoints[2]);
}

// Return true if a point is inside the collision shape
inline bool TriangleShape::testPointInside(const Vector3& localPoint, ProxyShape* proxyShape) const {
    return false;
}

}

#endif