#include <Parts.h>

Inheritance diagram for CGate:

Public Member Functions
	CGate (CLineSeg *p)
	Constructor. More...

	~CGate ()
	Destructor.

void	CloseGate ()
	Check latch to see if gate should be closed. More...

bool	NarrowPhase (CDynamicCircle *)
	Narrow phase collision detection and response. More...

Private Attributes
CLineSeg *	m_pLineSeg = nullptr
	Pointer to line segment representing gate.

bool	m_bOpen = false
	true if gate is open.

bool	m_bOccupied = false
	true if ball is holding gate open.

Additional Inherited Members
Static Protected Attributes inherited from CCommon
static CRenderer *	m_pRenderer = nullptr
	Pointer to the renderer.

static CObjectManager *	m_pObjectManager = nullptr
	Pointer to the object manager.

static UINT	m_nMIterations = 4
	Number of motion iterations.

static UINT	m_nCIterations = 1
	Number of collision iterations.

static float	m_fFrequency = 60.0f*m_nMIterations
	Frequency, number of physics iterations per second.

static eDrawMode	m_eDrawMode = eDrawMode::Background
	Draw mode.

static bool	m_bBallInPlay = false
	Is there a ball currently in play?

static UINT	m_nScore = 0
	Current score.

Detailed Description

A gate allows balls to cross in one direction only. It's essentially a line segment with a couple of Boolean variables and some code that handles the crossing-in-one-direction requirement. Care must be taken to do the right thing when a ball gets nudged back while in the process of crossing.

A gate can be open or closed, latched or unlatched. When it is open, there can be no collisions. When it is closed, balls collide with it if they are travelling from one side but not the other. More specifically, if the vector from the ball's center to the POI is in the opposite direction to the line segment's normal vector CLineSeg::m_vNormal then they can cross. Recall that the direction of CLineSeg::m_vNormal depends on the order in which CLineSeg's end points were specified, so make sure you get it right.

Constructor & Destructor Documentation

◆ CGate()

CGate::CGate ( CLineSeg * p )

Construct a closed and unlatched gate from a line segment.

Parameters

p	Pointer to a line segment.

Member Function Documentation

◆ CloseGate()

void CGate::CloseGate ( )

Close gate if open and there is no ball currently holding it open. Unset the occupied flag ready for use the the next frame. We assume that this is called at the end of the frame.

◆ NarrowPhase()

bool CGate::NarrowPhase ( CDynamicCircle * p )

If a dynamic circle collides with a gate and it is moving in the correct direction, then the gate opens and the dynamic circle is allowed through. Otherwise the dynamic circle bounces off the gate as usual.