D3DX Helper Objects

 

    D3DX除了提供concrete 类型外，也提供一些抽象的COM对象来执行渲染有关的任务。Matrix Stack 用于维护坐标体系。Font 和Sprite对象用于文字的渲染和屏幕空间纹理四边形的绘制。渲染到surface和渲染到环境map对象简化了第二个render target的使用和环境map纹理的构建。

    D3DX 也提供了一个对象用于实现可视效果。效果通过文本符号指定，并且使用了多个techniques来实现。每个technique由一组渲染passes和每个pass的渲染状态组成。效果也允许应用程序使用参数来控制。  

 

Matrix Stacks

   Matrix stack对于实现包含多个坐标系的scene graph很有帮助。D3DXCreateMatrixStack用来创建一个Matrix Stack.

   HRESULT D3DXCreateMatrixStack(DWORD zero,ID3DXMatrixStack ** result);

 

 ID3DXMatrixStack

Read-only Properties
GetTop	topmost matrix in the stack
Methods
LoadIdentity	Loads an Identity matrix
LoadMatrix	Loads an arbitrary matrix
MultMatrix	Post-multiplies a matrix
MultMatrixLocal	Pre-multiplies a matrix
Pop	Pops the topmost matrix from the stack
Push	Pushes a matrix onto the stack
RotateAxis	Post-mulitiplies a rotation matrix
RotateAxisLocal	Pre-multiplies a rotation matrix
RotateYawPitchRoll	Post-multiplies a rotation matrix
RotateYawPitchRollLocal	Pre-multiplies a rotation matrix
Scale	Post-multiplies a scaling matrix
ScaleLocal	Pre-multiplies a scaling matrix
Translate	Post-multiplies a translation matrix
TranslateLocal	Pre-multiplies a translation matrix

 

Fonts

 

  D3DX 提供了基于GDI渲染的ID3DXFont接口。使用这个接口，文字首先被GDI光栅化到内存DC，然后内存DC的内容将被拷贝到一个纹理，最后将这个纹理将被渲染到render target。 这个过程里面包含两个效率低的操作：GDI渲染，texture内容被必须被拷贝到设备内存。但这，这种方法渲染出来的文字质量很高，而且可以支持多字节和UNICODE的文字。

   HRESULT D3DXCreateFont (IDirect3DDevice9 * device,HFONT font, ID3DXFont ** result);

font参数指定了一个存在GDI font的句柄，

 

ID3DXFont

Read-only Properties
GetDC	GetDC
GetDescA	GetDescA
GetDescW	GetDescW
GetDevice	The associated device
GetGlyphData	GetGlyphData
GetTextMetricsA	GetTextMetricsA
GetTextMetricsW	GetTextMetricsW
Methods
DrawTextA	Render ASCII text
DrawTextW	Render UNICODE Text
OnLostDevice	Release device resource
PreloadCharacters	PreloadCharacters
PreloadGlyphs	PreloadGlyphs
PreloadTextA	PreloadTextA
PreloadTextW	PreloadTextW

 

Sprites

 

    Sprites是一个总是与屏幕平行的纹理化的四边形。D3DX使用ID3DXSprite实现一个sprite对象。D3DXCreateSprite用于创建一个sprite对象实例。

     HRESULT D3DXCreateSprite(IDirect3DDevice9 * device, ID3DXSprite ** result);

ID3DXSprite

Read-Only Properties
GetDevice	The associated device
Write-Only Properties
SetWorldViewLH	SetWorldViewLH
SetWorldVideRH	SetWorldViewRH
Properties
GetTransform
SetTransform
Methods
Begin	Begin
Draw	Draw
End	End
Flush	Flush
OnLostDevice	Release devices resource
OnResetDevice	Restore device resource

 

Surface Rendering

 

D3DX提供了ID3DXRenderToSurface接口简化了渲染到任意surface的过程。D3DXCreateRenderToSurface可以用来创建一个对象实例。

HRESULT D3DXCreateRenderToSurface(IDirect3DDevice9 * device, UINT width, UINT height, D3DFORMAT format, BOOL depth_stencil, D3DFORMAT ds_format, ID3DXRenderToSurface ** sesult);

ID3DXRenderToSurface

Read-only Properties
GetDesc	A description of the render target surface
GetDevice	The associated device
BeginScene	Start rendering to a surface
EndScene	Finish rendering to a surface
OnLostDevice	Release device resources
OnResetDevice	Restore device resources

 

Enviroment Map Rending

 

  HRESULT D3DXCreateRenderToEnvMap(IDirect3DDevice9 * device, UINT size, D3DFORMAT format, BOOL depth_stencil, D3DFORMAT ds_format, ID3DXRenderToEnvMap ** result);

ID3DXRenderToEnvMap

Read-Only Properties
GetDesc	A description of the render target used
GetDevice	The associated device
Methods
BeginCube	Begin rendering to a cube enviroment map
BeginHemisphere	Begin rendering to a hemispherical enviroment map
BeginParabolic	Begin rendering to a parabolic enviroment map
BeginSphere	Begin rendering to a spherical enviroment map
End	End rendering to an enviroment map
Face	Select a cubic enviroment map face for rendering
OnLostDevice	Releases device resources
OnResetDevice	Restores device resources