ghost.cpp

RGA: Biowaste Game Example This C++ application demonstrates how to create a 2D mobile game for S60

#include "Ghost.h"

CGhost::CGhost(CApplicationBase& aApp, CLevel& aLevel)
	:	CRotatingSprite(aApp),
		iLevel(aLevel)
	{
	}

CGhost::~CGhost()
	{
	}

TInt CGhost::Init(	IBitmap* aBitmap,
					IBitmap* aMask)
	{
	TInt error;
	error = CRotatingSprite::Init(aBitmap, aMask);
	if (error != KErrNone)
		{
		return error;
		}

	return KErrNone;
	}

		
void CGhost::Update(const TReal64 aFrametime)
	{
	// run ghost AI
	switch (Id())
		{
		case KBitmapGhostRed:
			UpdateAIRed(aFrametime);
			break;
			
		case KBitmapGhostGreen:
			UpdateAIGreen(aFrametime);
			break;
			
		case KBitmapGhostBlue:
			UpdateAIBlue(aFrametime);
			break;
		}
	
	// limit ghost speed
	if (Direction().LengthSq() > (iSpeed * iSpeed))
		{
		Direction().SetLength(iSpeed);
		}
	
	TSize levelsize = iLevel.SizeInPixels();
	
	// check level boundaries
	if (iPos.iX < 0.0)
		{
		iPos.iX = 0.0;
		iDir.iX = -iDir.iX * 0.5;
		}
	if (iPos.iX > levelsize.iWidth)
		{
		iPos.iX = levelsize.iWidth;
		iDir.iX = -iDir.iX * 0.5;
		}
	if (iPos.iY < 0.0)
		{
		iPos.iY = 0.0;
		iDir.iY = -iDir.iY * 0.5;
		}
	if (iPos.iY > levelsize.iHeight)
		{
		iPos.iY = levelsize.iHeight;
		iDir.iY = -iDir.iY * 0.5;
		}
	}


void CGhost::UpdateAIRed(const TReal64 aFrametime)
	{
	CRotatingSprite::Update(aFrametime);

	TVector2 dir;
	dir.iX = iPlayer->Position().iX - iPos.iX;
	dir.iY = iPlayer->Position().iY - iPos.iY;

	// accelerate towards player
	SetAcceleration(dir);
	}


void CGhost::UpdateAIGreen(const TReal64 aFrametime)
	{
	CRotatingSprite::Update(aFrametime);
	
	// get the point where ghost is moving to
	TVector2 goingto(iStartPos);
	if (iMovingToEndPos)
		{
		goingto = iEndPos;
		}
	
	// accelerate towards destination point
	TVector2 dir;
	dir.iX = goingto.iX - iPos.iX;
	dir.iY = goingto.iY - iPos.iY;
	
	SetAcceleration(dir);
	
	// check if ghost has reached the destination
	if (dir.LengthSq() < (32.0 * 32.0))
		{
		// switch target position
		iMovingToEndPos = !iMovingToEndPos;
		}
	}


void CGhost::UpdateAIBlue(const TReal64 aFrametime)
	{
	CSpriteBase::Update(aFrametime);
	
	// turn to face the player
	TVector2 dir;
	dir.iX = iPlayer->Position().iX - iPos.iX;
	dir.iY = iPlayer->Position().iY - iPos.iY;
	
	ComputeRotationAngle(dir);
	
	// pull player with pull force
	TVector2 pos = iPlayer->Position();
	const TReal32 radiussq = iPullForce * iPullForce;
	TReal32 ftemp, lensq;
	TReal64 length;
	
	lensq = dir.LengthSq();
	if (lensq > 0.0001 && lensq < radiussq)
		{
		Math::Sqrt(length, lensq);
		ftemp = 1.0f - (length / iPullForce);

		ftemp *= -iPullForce;
		ftemp *= aFrametime;
		dir.iX = dir.iX / length * ftemp;
		dir.iY = dir.iY / length * ftemp;
		pos.iX += dir.iX;
		pos.iY += dir.iY;
		iPlayer->SetPosition(pos);
		}
	}


	
void CGhost::Draw(IGraphicsContext& aContext, const TVector2& aCamera)
	{
	CRotatingSprite::Draw(aContext, aCamera);
	}


void CGhost::SetAIParams(	CSpriteBase* aPlayer,
							const TPoint& aStartPos,
							const TPoint& aEndPos,
							const TInt aExtraParam,
							const TInt aType)
	{
	iPlayer = aPlayer;
	iStartPos = aStartPos;
	iEndPos = aEndPos;
	
	// set the id to the ghost to run separate AI for each
	SetId(aType);
	
	// set the starting position
	SetPosition(TVector2(iStartPos));
	
	// set the extra param
	switch (aType)
		{
		case KBitmapGhostRed:
			iSpeed = (TReal64)aExtraParam;
			break;

		case KBitmapGhostGreen:
			iSpeed = (TReal64)aExtraParam;
			iMovingToEndPos = ETrue;
			break;
			
		case KBitmapGhostBlue:
			iSpeed = 0.0;
			iPullForce = (TReal64)aExtraParam;
			break;
		}
	}