gaia源码分析 - 军军小站|张军博客

最近在看《Real Time 3D Terrain Engines Using C++And DirectX 9》，不过是看网上翻译的版本叫《实时地形引擎》 ，看英文实在蛋疼，还好有翻译版的，要多多感谢承天一大哥！这本书讲解了地形制作的一些技术，更吸引人的是实现了一个小型的渲染引擎，对于我这样的游戏引擎初学者很适合。gaia正是书中构建的引擎的名字。这里来写写一些简单的分析，作为学习笔记。

（一） 资源管理

1、 data_pool.h

cPoolGroup : 模板类，池组，顾名思义，就是装载一组数据的对象

template < class T>
class cPoolGroup
{
public :

cPoolGroup(uint16 maxCount);
~cPoolGroup(){};

void create();
void destroy();

uint16 addMember( const T& member);
uint16 nextMember();
void release(uint16 index);

uint16 totalOpen() const ;
uint16 totalUsed() const ;
uint16 firstOpen() const ;
bool isOpen(uint16 index) const ;
T& member(uint16 index);
const T& member(uint16 index) const ;
T* memberPtr(uint16 index);
const T* memberPtr(uint16 index) const ;

private :
uint16 m_totalOpen;
uint16 m_firstOpen;
uint16 m_maxCount;
uint16* m_nextOpenList;
T* m_memberList; // 数据对象链表
};

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cDataPoolInterface ：数据池接口，抽象类

class cDataPoolInterface
{
public :
typedef void (*MEMBER_CALLBACK)(cDataPoolInterface* pPool, cPoolHandle handle, void * member);

cDataPoolInterface():m_initialized( false ){};
virtual ~cDataPoolInterface(){};

virtual void initialize(uint16 growSize)= 0 ;;
virtual void destroy()= 0 ;;
virtual void clear()= 0 ;
virtual cPoolHandle nextHandle()= 0 ;
virtual void release(cPoolHandle* pHandle)= 0 ;
virtual void forEach(MEMBER_CALLBACK function)= 0 ;

virtual void * getGenericPtr(cPoolHandle index)= 0 ;

bool isInitialized() const { return m_initialized;}

protected :
bool m_initialized;
};

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cDataPool ：模板类，继承自 cDataPoolInterface ，数据池，它包括了若干个 cPoolGroup

template < class T>
class cDataPool : public cDataPoolInterface
{
public :

// Data Types & Constants...
typedef T DATA_TYPE;
typedef cPoolGroup<T> MemberGroup;
typedef std::list<MemberGroup*> MemberGroupList;
typedef cDataPoolInterface::MEMBER_CALLBACK MEMBER_CALLBACK;

// Creators...
cDataPool();
~cDataPool();

void initialize(uint16 growSize);
void destroy();

const T& operator [](cPoolHandle handle) const { return get (handle);}
T& operator [](cPoolHandle handle) { return get (handle);}

// Mutators...
cPoolHandle add( const T& member);
void clear();
cPoolHandle nextHandle();
void release(cPoolHandle* pHandle);
void forEach(MEMBER_CALLBACK function);

// Accessors...
bool isHandleValid(cPoolHandle index) const ;
const T& get (cPoolHandle index) const ;
T* getPtr(cPoolHandle index);
void * getGenericPtr(cPoolHandle index);

uint16 totalMembers() const { return m_totalMembers;}
uint16 totalOpen() const { return m_totalOpen;}
uint16 totalUsed() const { return m_totalMembers-m_totalOpen;}

private :

// Private Data...
MemberGroupList m_groupList; // cPoolGroup链表
uint16 m_totalMembers;
uint16 m_totalOpen;
uint16 m_groupCount;
uint32 m_indexMask;
int m_indexShift;

// Private Functions...
explicit cDataPool( const cDataPool& Src);
cDataPool& operator =( const cDataPool& Src);

cPoolGroup<T>* addGroup();
cPoolGroup<T>* findOpenGroup(unsigned* groupNumber);
cPoolGroup<T>* getGroup(unsigned index);
const cPoolGroup<T>* getGroup(unsigned index) const ;

int getGroupNumber(cPoolHandle handle) const ;
int getItemIndex(cPoolHandle handle) const ;
cPoolHandle buildHandle( int group, int index) const ;

};

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2、 resource_pool.h

cResourcePoolInterface ：资源池接口，抽象类

class cResourcePoolInterface
{
public :

union FILE_EXTENSION
{
char ext[ 4 ];
uint32 fourcc;
};

typedef std::map<cString, cPoolHandle> NAME_LOOKUP_MAP;

cResourcePoolInterface();
virtual ~cResourcePoolInterface(){};

// these functions must be proviided in the derived class (cResourceType)
virtual void initialize(uint16 growSize)= 0 ;
virtual void destroy()= 0 ;
virtual bool isInitialized() const = 0 ;

virtual void destroyAll()= 0 ;
virtual void disableAll()= 0 ;
virtual void restoreAll()= 0 ;
virtual void clean()= 0 ;

cResourcePoolItem* createResource( const cString& resourceName);
cResourcePoolItem* loadResource( const cString& filename);
cResourcePoolItem* getResource(cPoolHandle handle);
cResourcePoolItem* findResource( const cString& Name);
void destroyResource(cResourcePoolItem* pResource);

bool saveResource(cResourcePoolItem* pResource);

cPoolHandle findResourceHandle( const cString& Name);
const cString* findResourceName(cPoolHandle handle) const ;
void setResourceName(cPoolHandle handle, const tchar* name);

void registerResourcePool(cResourceCode code);
void unregisterResourcePool();

cResourceCode registrationCode() const ;

protected :
cResourceCode m_registrationCode;
NAME_LOOKUP_MAP m_nameMap;

private :
// Private Functions...
virtual cPoolHandle internalCreateResource( const cString& resourceName)= 0 ;
virtual void internalDestroyResource(cPoolHandle handle)= 0 ;
virtual cResourcePoolItem* internalGetResource(cPoolHandle handle)= 0 ;
};

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cResourcePool：模板类，资源池，继承自cResourcePoolInterface，成员中有一个DataPool可以看做是DataPool的扩充。

template < class T>
class cResourcePool : public cResourcePoolInterface
{
public :

typedef T DataType;
typedef cDataPool<T> DataPool;

// Creators...
cResourcePool(){};
~cResourcePool(){};

// Base Class Overrides...
void initialize(uint16 growSize);
void destroy();
bool isInitialized() const ;

void destroyAll();
void disableAll();
void restoreAll();
void clean(); // delete items no longer referenced

DataType* createResource( const cString& resourceName);
DataType* loadResource( const cString& filename);
DataType* getResource(cPoolHandle handle);
DataType* findResource( const cString& Name);

// static data pool callbacks
static void callbackDestroy(cDataPoolInterface* pPool, cPoolHandle handle, void * resource);
static void callbackRestore(cDataPoolInterface* pPool, cPoolHandle handle, void * resource);
static void callbackDisable(cDataPoolInterface* pPool, cPoolHandle handle, void * resource);
static void callbackClean(cDataPoolInterface* pPool, cPoolHandle handle, void * resource);

private :

// Data...
DataPool m_dataPool;

// Private Functions...
cPoolHandle internalCreateResource( const cString& resourceName);
void internalDestroyResource(cPoolHandle handle);
cResourcePoolItem* internalGetResource(cPoolHandle handle);

// Nonexistant Functions...

cResourcePool( const cResourcePool& Src);
cResourcePool& operator =( const cResourcePool& Src);
};

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cResourcePoolItem ：资源池对象继承自 cReferenceCounter

关于 cReferenceCounter 上一段英文：

/*    cResourcePoolItem

------------------------------------------------------------------------------------------



       A cResourcePoolItem is a simple base class for a shared resource such as a texture,

       animation or vertex buffer.

       Note that cResourcePoolItem is derived from cReferenceCounter. The cResourcePoolManager uses

       the value of the cReferenceCounter to decide when objects are no longer in use and can

       be destroyed during the cResourcePoolManager::clean() function. This means the application

       must update the reference count of the cResourcePoolItem whenever links between objects

       are created or removed between objects. The cReferenceCounter base class provides the

       functionality to manipulate the reference count.



------------------------------------------------------------------------------------------

*/

class cResourcePoolItem : public cReferenceCounter
{
public :

// Data Types & Constants...
enum
{
nCreated= 0 , // the resource has been created
nLoaded, // the resource is filled with data and ready for use
nDisabled, // the resource is currently disabled for use
nAltered, // the resource has been altered since loaded
nTotalResourceFlags
};

// Creators...
cResourcePoolItem();
virtual ~cResourcePoolItem();

// User Functions
// These function prototypes are to be used by resources that use volatile or system-specific resources.
// Examples would be video-memory resident textures or hardware vertex buffers.
virtual bool createResource()= 0 ; // innitialize the resource (called once)
virtual bool destroyResource()= 0 ; // destroy the resource
virtual bool disableResource()= 0 ; // purge the resource from volatile memory
virtual bool restoreResource()= 0 ; // restore the resource to volatile memory
virtual bool loadResource( const tchar* filename= 0 )= 0 ; // load the resource from a file (or NULL to use the resource name)
virtual bool saveResource( const tchar* filename= 0 )= 0 ; // save the resource to a file (or NULL to use the resource name)

// Accessors...
cResourceCode resourceCode() const ;
cResourcePoolInterface* resourcePool() const ;
cPoolHandle resourceHandle() const ;
u32Flags resourceFlags() const ;

bool isResourceCreated() const ;
bool isResourceDisabled() const ;
bool isResourceLoaded() const ;
const cString* findResourceName() const ;

void setResourceName( const tchar* name);
void setAlteredFlag( bool onOff);
bool alteredFlag() const ;

// mimic COM interfaces
virtual int32 Release();

protected :

// only derrived classes are permitted to modify internal members
void setResourceCode(cResourceCode code);
void setResourcePool(cResourcePoolInterface* interfaePtr);
void setResourceHandle(cPoolHandle handle);
void setResourceFlag( int flagBit, bool Setting);

void notifyCreated();
void notifyDisabled();
void notifyLoaded();
void notifyUnloaded();
void notifyRestored();
void notifyDestroyed();
void notifySaved();

private :

// Data...
cResourceCode m_resourceCode;
cResourcePoolInterface* m_resourcePool;
cPoolHandle m_resourceHandle;
u32Flags m_resourceFlags;

// Private Functions...

// Nonexistant Functions...
cResourcePoolItem( const cResourcePoolItem& Src);
cResourcePoolItem& operator =( const cResourcePoolItem& Src);

friend cResourcePoolInterface;
};

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cReferenceCounter：。。（我没太理解它的作用，望大虾指点。。）

/*    cReferenceCounter

-----------------------------------------------------------------



       A cReferenceCounter is a base class which allows the program

       to count open instances.



-----------------------------------------------------------------

*/

class cReferenceCounter
{
public :

// Construction and Destruction...
cReferenceCounter()
{
m_nReferenceCount = 0 ;
}

cReferenceCounter( const cReferenceCounter& Src)
{
// Reference counts are tied to a specific instance
// i.e. they are never copied
m_nReferenceCount = 0 ;
}

virtual ~cReferenceCounter()
{
// assert if this object is still in use
assert(m_nReferenceCount == 0 );
}

// Operators...
cReferenceCounter& operator =( const cReferenceCounter& Src)
{
// this function is provided in order to allow
// derived classes to provide copy operators.
// the reference count itself is never copied.
return * this ;
}

// Mutators...
virtual int32 AddRef()
{
assert(m_nReferenceCount != MAX_INT32);
++m_nReferenceCount;
return (m_nReferenceCount);
};

virtual int32 Release()
{
assert(m_nReferenceCount > 0 );
--m_nReferenceCount;
return (m_nReferenceCount);
}

// Accessors...
int32 referenceCount() const { return m_nReferenceCount;}

private :

// the internal reference count, stored in 32bits
int32 m_nReferenceCount;
};

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cResourcePoolManager ：单件类，资源管理器，负责申请资源池，找到资源等资源管理功能。

class cResourcePoolManager : public cSingleton<cResourcePoolManager>
{
public :

typedef std::map<cResourceCode, cResourcePoolInterface*> ResourcePoolTypeMap;
typedef std::list<cResourcePoolInterface*> ResourcePoolFamilyList;

// Creators...
cResourcePoolManager();
~cResourcePoolManager(){};

// registration of resource manager interfaces
void registerResourcePool(cResourceCode code, cResourcePoolInterface* pInterface);
cResourcePoolInterface* unregisterResourcePool(cResourceCode code);

// operations for all resource types
void destroyAll();
void disableAll();
void restoreAll();
void clean(); // delete items no longer referenced

// operations on specific resource types
void destroyResourceFamily( int family);
void disableResourceFamily( int family);
void restoreResourceFamily( int family);
void cleanResourceFamily( int family);

void destroyResourceType(cResourceCode code);
void disableResourceType(cResourceCode code);
void restoreResourceType(cResourceCode code);
void cleanResourceType(cResourceCode code);

cResourcePoolInterface* findResourcePool(cResourceCode code) const ;
cPoolHandle findResourceHandle(cResourceCode code, const cString& Name) const ;
cResourcePoolItem* findResource(cResourceCode code, const cString& Name) const ;
cResourcePoolItem* findResource(cResourceCode code, cPoolHandle handle) const ;

private :

ResourcePoolFamilyList m_resourceFamilyList[k_nTotalResourceFamilies];
ResourcePoolTypeMap m_resourceTypeMap;
};

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引擎中所有的资源都派生自 cResourcePoolItem ，也可以说是对 D3D 资源类的封装。例如： texture.h 里的 cTexture：

class cTexture : public cResourcePoolItem
{
public :

// Data Types & Constants...
enum eTextureFlags
{
k_cubeMap= 0 ,
k_dynamicTexture,
k_renderTarget,
k_paletized,
k_mipMaps,
};

enum eForcedFormatFlags
{
k_forceMipLevels= 0 ,
k_forceFormat,
k_forceSize,
};

// Creators...

cTexture();
~cTexture();

// base resource overrides
bool createResource(); // innitialize the resource (called once)
bool destroyResource(); // destroy the resource
bool disableResource(); // purge the resource from volatile memory
bool restoreResource(); // prepare the resource for use (create any volatile memory objects needed)
bool loadResource( const tchar* filename= 0 ); // load the resource from a file (or NULL to use the resource name)
bool saveResource( const tchar* filename= 0 ); // save the resource to a file (or NULL to use the resource name)

bool createTexture(uint32 width, uint32 height, uint32 mipLevels, uint32 usage, D3DFORMAT Format, D3DPOOL pool);
bool createCubeTexture(uint32 size, uint32 mipLevels, uint32 usage, D3DFORMAT Format, D3DPOOL pool);
void generateMidpointNoise( float falloff);
void generatePerlinNoise( float scale, int octaves, float falloff);
bool generateNormalMap(LPDIRECT3DTEXTURE9 heightMap, uint32 channel, uint32 flags, float amplitude);
bool generateNormalizationCubeMap();
bool maskWithImage(cImage* pImage);

void releaseTexture();

bool convertToNormalMap(
uint32 channel,
uint32 flags,
float amplitude);

// Accessors...
LPDIRECT3DTEXTURE9 getTexture() const ;
bool uploadImage( const cImage* pImage, bool copyAll = true );
bool uploadCubeFace( const cImage* pImage, D3DCUBEMAP_FACES face, bool copyAll = true );

uint32 width() const { return m_width;}
uint32 height() const { return m_height;}
uint32 mipLevels() const { return m_mipLevels;}
uint32 d3dUsage() const { return m_d3dUsage;}
D3DFORMAT d3dFormat() const { return m_d3dFormat;}
D3DPOOL d3dPool() const { return m_d3dPool;}

bool getSurfaceLevel( int level, LPDIRECT3DSURFACE9* ppSurface);
private :

// Data...
uint32 m_width;
uint32 m_height;
uint32 m_mipLevels;
uint32 m_d3dUsage;
D3DFORMAT m_d3dFormat;
D3DPOOL m_d3dPool;
DWORD m_d3dFilter;
DWORD m_d3dMipFilter;
D3DCOLOR m_d3dColorKey;
D3DXIMAGE_INFO m_d3dImageInfo;
PALETTEENTRY* m_pPalette;
LPDIRECT3DTEXTURE9 m_pTexture;
LPDIRECT3DCUBETEXTURE9 m_pCubeTexture;

bool loadFromResourceFile(cFile& InputFile);
bool configureImageSettings();
bool checkTextureRequirements();
bool checkCubeTextureRequirements();

bool loadTextureFromImageFile( const tchar* filename);
bool loadTextureFromMemory(uint8* memory, uint32 size);
bool loadCubeTextureFromImageFile( const tchar* filename);
bool loadCubeTextureFromMemory(uint8* memory, uint32 size);

// Nonexistant Functions...
cTexture( const cTexture& Src);
cTexture& operator =( const cTexture& Src);

};

typedef cResourcePool<cTexture> cTextureManager;

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此外还有 vertex_buffer.h 中的 cVertexBuffer 和 model_resource.h 中的 cModelResource

P56 有资源的使用示例

类关系图：

由 cResourcePoolManager 统一管理。

书的第四章gaia引擎总览有提到资源管理相关的内容，但是并没用对源码进行过多的解释，这部分还是要自己硬着头皮看啊。。。

不过看了这些基本理解了资源管理的原理和整个模块的结构，受益匪浅。。

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gaia源码分析

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