sgdk::Compass<> Class Template Reference
[Compass Module]

#include <swiss_gd_knife/math/geom/compass.hpp>

List of all members.

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Detailed Description

template<>
class sgdk::Compass<>

The example below illustrates the usage of this class.

// std::ostream and std::cout
#include <iostream>
// sgdk::ZeroDirection, sgdk::PositiveRotation, and sgdk::Compass
#include <swiss_gd_knife/math/geom/compass.hpp>

typedef sgdk::Compass<>
        SampleCompass;

/*
 * Outputs the compass.getDirection() call's parameters and its result.
 */
void
    coutDirection(
        const SampleCompass& compass
      , const double dx
      , const double dy
    )
{
    std::cout << "<" << dx << ", " << dy << "> = ";
    std::cout << compass.getDirection(dx, dy) << std::endl;
}

/*
 * Runs the specified example's invocations of the getDirection()
 * function of the specified Compass with its current zero-direction,
 * positive-rotation, and direction-count settings.
 */
void sample(const SampleCompass& compass, const unsigned int trial)
{
    std::cout << "Number of directions = ";
    std::cout << compass.getDirectionCount() << std::endl;

    switch (trial)
    {
        case 1:
            coutDirection(compass, 0, 1);
            coutDirection(compass, 1, 0);
            coutDirection(compass, 0, -1);
            coutDirection(compass, -1, 0);
            coutDirection(compass, 1, 2);
            coutDirection(compass, 2, 1);
            coutDirection(compass, 2, -1);
            coutDirection(compass, 1, -2);
            coutDirection(compass, -1, -2);
            coutDirection(compass, -2, -1);
            coutDirection(compass, -2, 1);
            coutDirection(compass, -1, 2);
            break;

        case 2:
            coutDirection(compass, 1, 5);
            coutDirection(compass, 3, 4);
            coutDirection(compass, 5, 1);
            coutDirection(compass, 5, -1);
            coutDirection(compass, 3, -4);
            coutDirection(compass, 1, -5);
            coutDirection(compass, -1, -5);
            coutDirection(compass, -3, -4);
            coutDirection(compass, -5, -1);
            coutDirection(compass, -5, 1);
            coutDirection(compass, -3, 4);
            coutDirection(compass, -1, 5);
            break;

        case 3:
            coutDirection(compass, 0, 1);
            coutDirection(compass, 1, 1);
            coutDirection(compass, 1, 0);
            coutDirection(compass, 1, -1);
            coutDirection(compass, 0, -1);
            coutDirection(compass, -1, -1);
            coutDirection(compass, -1, 0);
            coutDirection(compass, -1, 1);
            break;

        default:
            coutDirection(compass, 0, 2);
            coutDirection(compass, 1, 2);
            coutDirection(compass, 2, 2);
            coutDirection(compass, 2, 1);
            coutDirection(compass, 2, 0);
            coutDirection(compass, 2, -1);
            coutDirection(compass, 2, -2);
            coutDirection(compass, 1, -2);
            coutDirection(compass, 0, -2);
            coutDirection(compass, -1, -2);
            coutDirection(compass, -2, -2);
            coutDirection(compass, -2, -1);
            coutDirection(compass, -2, 0);
            coutDirection(compass, -2, 1);
            coutDirection(compass, -2, 2);
            coutDirection(compass, -1, 2);
            break;
    }

    std::cout << std::endl;
}

/*
 * Runs the examples on the specified Compass with its current zero-direction
 * and positive-rotation settings.  Groups the output directions by direction
 * count.
 */
void sample(SampleCompass& compass)
{
    // Basic cases.
    compass.setDirectionCount(4);
    sample(compass, 1);
    compass.setDirectionCount(5);
    sample(compass, 2);
    compass.setDirectionCount(8);
    sample(compass, 3);
    compass.setDirectionCount(10);
    sample(compass, 2);
    compass.setDirectionCount(16);
    sample(compass, 0);

    // Degenerate cases.
    compass.setDirectionCount(1);
    sample(compass, 1);
    compass.setDirectionCount(2);
    sample(compass, 1);
    compass.setDirectionCount(3);
    sample(compass, 0);

    // See how a "real-world" compass works.
    compass.setDirectionCount(360);
    sample(compass, 0);

    // Unreal Tournament angles.
    compass.setDirectionCount(65536);
    sample(compass, 0);
}

/*
 * Runs the examples.
 */
int main()
{
    std::cout << "ZeroDirection = Y, PositiveRotation = CW" << std::endl;
    SampleCompass
        compass(
            4
          , sgdk::ZeroDirection::POSITIVE_Y_AXIS
          , sgdk::PositiveRotation::CLOCKWISE
        );
    sample(compass);

    std::cout << "ZeroDirection = Y, PositiveRotation = CCW" << std::endl;
    compass.setPositiveRotation(sgdk::PositiveRotation::COUNTERCLOCKWISE);
    sample(compass);

    std::cout << "ZeroDirection = -Y, PositiveRotation = CW" << std::endl;
    compass.setZeroDirection(sgdk::ZeroDirection::NEGATIVE_Y_AXIS);
    compass.setPositiveRotation(sgdk::PositiveRotation::CLOCKWISE);
    sample(compass);

    std::cout << "ZeroDirection = -Y, PositiveRotation = CCW" << std::endl;
    compass.setPositiveRotation(sgdk::PositiveRotation::COUNTERCLOCKWISE);
    sample(compass);

    std::cout << "ZeroDirection = X, PositiveRotation = CW" << std::endl;
    compass.setZeroDirection(sgdk::ZeroDirection::POSITIVE_X_AXIS);
    compass.setPositiveRotation(sgdk::PositiveRotation::CLOCKWISE);
    sample(compass);

    std::cout << "ZeroDirection = X, PositiveRotation = CCW" << std::endl;
    compass.setPositiveRotation(sgdk::PositiveRotation::COUNTERCLOCKWISE);
    sample(compass);

    std::cout << "ZeroDirection = -X, PositiveRotation = CW" << std::endl;
    compass.setZeroDirection(sgdk::ZeroDirection::NEGATIVE_X_AXIS);
    compass.setPositiveRotation(sgdk::PositiveRotation::CLOCKWISE);
    sample(compass);

    std::cout << "ZeroDirection = -X, PositiveRotation = CCW" << std::endl;
    compass.setPositiveRotation(sgdk::PositiveRotation::COUNTERCLOCKWISE);
    sample(compass);

    return 0;
}

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Template parameters

Parameter	Description	Default
Direction	The return type of getDirection().	unsigned int
DirectionChange	The return type of getDirectionChange().	int
PiConstant	The type of the function object returning the constant value PI.	Pi
TangentFunction	The type of the function object returning the tangent of an angle.	Tangent

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Model of:

• Assignable
• Default Constructible
• Copy Constructible

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Type requirements

• Direction must be an unsigned integral type.
• DirectionChange must be a signed integral type.
• PiConstant must be a nullary function object.
• TangentFunction must model the Adaptable Unary Function and Default Constructible concepts.
• PiConstant::value_type must be convertible to TangentFunction::argument_type.

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Public Types
typedef implementation_defined	RealNumber
Public Member Functions
	Compass (const Direction direction_count=4, const ZeroDirection &zero_direction=ZeroDirection::POSITIVE_Y_AXIS, const PositiveRotation &positive_rotation=PositiveRotation::CLOCKWISE, const RealNumber zero_tolerance=0.00001f)
	The default constructor.
	Compass (const Compass &copy)
	The copy constructor.
Compass &	operator= (const Compass &copy)
	The assignment operator.
Direction	getDirectionCount () const
Direction	getDirection (const RealNumber dx, const RealNumber dy) const
DirectionChange	getDirectionChange (const RealNumber dx1, const RealNumber dy1, const RealNumber dx2, const RealNumber dy2) const
void	setDirectionCount (const Direction direction_count)
void	setZeroDirection (const ZeroDirection &zero_direction)
void	setPositiveRotation (const PositiveRotation &positive_rotation)

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Member Typedef Documentation

typedef implementation_defined sgdk::Compass<>::RealNumber

The type of the arguments for getDirection().

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Constructor & Destructor Documentation

sgdk::Compass<>::Compass (  const Direction  direction_count = 4, const ZeroDirection &  zero_direction = ZeroDirection::POSITIVE_Y_AXIS, const PositiveRotation &  positive_rotation = PositiveRotation::CLOCKWISE, const RealNumber  zero_tolerance = 0.00001f )  [inline, explicit]

Constructs a new Compass. Parameters: direction_count  the number of possible rotation outputs. The default value is 4. zero_direction  the "zero-degree direction" identified by this Compass. The default is ZeroDirection::POSITIVE_Y_AXIS. positive_rotation  the rotational direction that this Compass identifies as upward from zero_direction. The default is PositiveRotation::CLOCKWISE. zero_tolerance  the threshold used to internally check for special divide-by-zero cases. The default value is 0.00001f. See also: setDirectionCount(), setZeroDirection(), setPositiveRotation()

sgdk::Compass<>::Compass (  const Compass<> &  copy  )  [inline]

Constructs a new Compass that will be internally equivalent to the copy at this point in time. Parameters: copy  the Compass being copied.

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Member Function Documentation

Compass& sgdk::Compass<>::operator= (  const Compass<> &  copy  )  [inline]

Sets this Compass to be internally equivalent to the copy. Parameters: copy  the Compass being copied. Returns: a reference to this Compass.

Direction sgdk::Compass<>::getDirectionCount (   )  const [inline]

Returns the number of possible rotation outputs for this Compass. Returns: the number of possible values that getDirection() can return.

Direction sgdk::Compass<>::getDirection (  const RealNumber  dx, const RealNumber  dy )  const

The direction-finding function. Returns zero if exactly one of the following conditions holds: dx <= 0, dy == 0, and the zero-direction is ZeroDirection::NEGATIVE_X_AXIS. dx == 0, dy <= 0, and the zero-direction is ZeroDirection::NEGATIVE_Y_AXIS. dx >= 0, dy == 0, and the zero-direction is ZeroDirection::POSITIVE_X_AXIS. dx == 0, dy >= 0, and the zero-direction is ZeroDirection::POSITIVE_Y_AXIS. Returns getDirectionCount() / 2 if getDirectionCount() returns an even number and exactly one of the following conditions holds: dx > 0, dy == 0, and the zero-direction is ZeroDirection::NEGATIVE_X_AXIS. dx == 0, dy > 0, and the zero-direction is ZeroDirection::NEGATIVE_Y_AXIS. dx < 0, dy == 0, and the zero-direction is ZeroDirection::POSITIVE_X_AXIS. dx == 0, dy < 0, and the zero-direction is ZeroDirection::POSITIVE_Y_AXIS. Returns a value between zero and getDirectionCount() / 2 if exactly one of the following conditions holds: dx > 0, the zero-direction is ZeroDirection::POSITIVE_Y_AXIS, and the positive rotation is PositiveRotation::CLOCKWISE. dx < 0, the zero-direction is ZeroDirection::POSITIVE_Y_AXIS, and the positive rotation is PositiveRotation::COUNTERCLOCKWISE. dx > 0, the zero-direction is ZeroDirection::NEGATIVE_Y_AXIS, and the positive rotation is PositiveRotation::COUNTERCLOCKWISE. dx < 0, the zero-direction is ZeroDirection::NEGATIVE_Y_AXIS, and the positive rotation is PositiveRotation::CLOCKWISE. dy > 0, the zero-direction is ZeroDirection::POSITIVE_X_AXIS, and the positive rotation is PositiveRotation::COUNTERCLOCKWISE. dy < 0, the zero-direction is ZeroDirection::POSITIVE_X_AXIS, and the positive rotation is PositiveRotation::CLOCKWISE. dy > 0, the zero-direction is ZeroDirection::NEGATIVE_X_AXIS, and the positive rotation is PositiveRotation::CLOCKWISE. dy < 0, the zero-direction is ZeroDirection::NEGATIVE_X_AXIS, and the positive rotation is PositiveRotation::COUNTERCLOCKWISE. Returns a value between getDirectionCount() / 2 and getDirectionCount() if exactly one of the following conditions holds: dx < 0, the zero-direction is ZeroDirection::POSITIVE_Y_AXIS, and the positive rotation is PositiveRotation::CLOCKWISE. dx > 0, the zero-direction is ZeroDirection::POSITIVE_Y_AXIS, and the positive rotation is PositiveRotation::COUNTERCLOCKWISE. dx < 0, the zero-direction is ZeroDirection::NEGATIVE_Y_AXIS, and the positive rotation is PositiveRotation::COUNTERCLOCKWISE. dx > 0, the zero-direction is ZeroDirection::NEGATIVE_Y_AXIS, and the positive rotation is PositiveRotation::CLOCKWISE. dy < 0, the zero-direction is ZeroDirection::POSITIVE_X_AXIS, and the positive rotation is PositiveRotation::COUNTERCLOCKWISE. dy > 0, the zero-direction is ZeroDirection::POSITIVE_X_AXIS, and the positive rotation is PositiveRotation::CLOCKWISE. dy < 0, the zero-direction is ZeroDirection::NEGATIVE_X_AXIS, and the positive rotation is PositiveRotation::CLOCKWISE. dy > 0, the zero-direction is ZeroDirection::NEGATIVE_X_AXIS, and the positive rotation is PositiveRotation::COUNTERCLOCKWISE. Parameters: dx  the change in x-coordinate value from the point of origin of this Compass. dy  the change in y-coordinate value from the point of origin of this Compass. Returns: the closest discrete direction. Invariant: 0 <= getDirection(dx,dy) getDirection(dx,dy) < getDirectionCount() See also: getDirectionChange()

DirectionChange sgdk::Compass<>::getDirectionChange (  const RealNumber  dx1, const RealNumber  dy1, const RealNumber  dx2, const RealNumber  dy2 )  const

Returns the change in direction between getDirection(dx1,dy1) and getDirection(dx2,dy2) as defined by this Compass. Parameters: dx1  the starting change in x-coordinate value from the point of origin of this Compass. dy1  the starting change in y-coordinate value from the point of origin of this Compass. dx2  the ending change in x-coordinate value from the point of origin of this Compass. dy2  the ending change in y-coordinate value from the point of origin of this Compass. Returns: a negative number if this Compass defines the resulting change as downward, a positive number if this Compass defines the change as upward, or zero if there is no perceptible change. A change to the opposite direction is considered upward; if getDirectionCount() returns an even number, then this particular getDirectionChange() call will return half that value.

void sgdk::Compass<>::setDirectionCount (  const Direction  direction_count  )  [inline]

Sets the number of possible rotation outputs. Parameters: direction_count  the new number of possible rotation outputs. See also: Compass()

void sgdk::Compass<>::setZeroDirection (  const ZeroDirection &  zero_direction  )  [inline]

Sets the zero-degree direction for this Compass. Parameters: zero_direction  the zero-degree direction to be identified by this Compass. See also: Compass()

void sgdk::Compass<>::setPositiveRotation (  const PositiveRotation &  positive_rotation  )  [inline]

Sets the positive rotational direction for this Compass. Parameters: positive_rotation  the rotational direction that this Compass will identify as upward from the zero-degree direction. See also: Compass()

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