SDL Custom Input

#include <string>#include <map>#include <exception>#include <sstream>#include <boost/shared_ptr.hpp>class InputBind {protected:	InputManager&	mInput;public:	InputBind( InputManager& input ) : mInput( input ) {	}		virtual ~InputBind() {	}		virtual float GetTriggerState() const = 0;	// For buttons, keys, and etc	virtual bool GetAxisState() const = 0; // For axes, returns range from, 0.f to 1.f};class KeyBind : public InputBind {public:	unsigned	mWhichKeyPos;	// If used in place of a joy axis, this is the key for +axis	unsigned	mWhichKeyNeg;	// and for -axis.  If this is a regular key press, then this is ignored	public:	KeyBind( InputManager& i, unsigned keypos, unsigned keyneg = 0 ) 		: InputBind( i )		, mWhichKeyPos( keypos )		, mWhichKeyNeg( keyneg ) {	}		bool GetTriggerState() const {		// Returns either of the buttons state state		return mInput.IsKeyDown( mWhichKeyPos ) || mInput.IsKeyDown( mWhichKeyNeg );	}		float GetAxisState() const {		// Returns -1 when mWhichKeyNeg is pressed, 1 when mWhichKeyPos is pressed		// or 0 when none or both are pressed.		return 			(mInput.IsKeyDown( mWhichKeyPos ) ? 1.f : 0.f) + 			(mInput.IsKeyDown( mWhichKeyNeg ) ? -1.f : 0.f );	}};class AxisBind : public InputBind {public:	unsigned	mWhichJoy;	unsigned	mWhichAxis;		// If an axis is used in place of a key press, this is the minimum value the 	// axis state must be in order for the press to be registered.	float		mThreshold;	public:	AxisBind( InputManager& i, unsigned joy, unsigned axis, float thres = 0.f ) 		: mWhichJoy( joy )		, mWhichAxis( axis )		, mThreshold( thres ) {	}	private:	float GetAxisState() const { 		// Returns the state of the axis		return mInput.GetJoystick( mWhichJoy ).GetAxis( mWhichAxis );	}public:		bool GetTriggerState() const {		return std::abs( GetAxisState() ) < mThreshold ? true : false;	}		bool GetAxisState() const {		return GetAxisState();	}};class BindMap {public:	typedef boost::shared_ptr<InputBind> 		SharedBind;	typedef std::map<std::string, SharedBind>	BindMap;	private:	BindMap		mBinds;public:		const InputBind* operator[] ( const std::string& name ) {		// Probably add some checks here, throw an exception		// on an attempt to access a bind that doesn't exists		// or log the message then return a dummy bind.		return mBinds[ name ].get();	}		// Assumes ownership of "bind":	void RegisterBind( const std::string& name, InputBind* bind ) {		mBinds[ name ] = SharedBind( bind );	}};// Usage:void Player::RegisterTestBinds( BindMap& binds, InputManager& i ) {	binds.RegisterBind( "PLAYER_MOVE_XAXIS", new AxisBind( i, 0, 0 ) );	binds.RegisterBind( "PLAYER_MOVE_YAXIS", new KeyBind( i, SDLK_UP, SDLK_DOWN ) );	binds.RegisterBind( "PLAYER_JUMP", new KeyBind( i, SDLK_SPACE ) );}bool Player::Update( BindMap& binds, float dt ) {	Vector2 drive = Vector2( 		// Either a button/key or an axis, GetAxisState will return anything between -1 and 1:		binds[ "PLAYER_MOVE_XAXIS" ]->GetAxisState(),			binds[ "PLAYER_MOVE_YAXIS" ]->GetAxisState() );	float jump = 0.f;	if ( this->IsOnGround() && binds[ "PLAYER_JUMP" ].get()->GetTriggerState() ) 		jump = 1.f;			return false;}