DXUT框架剖析（7）

最新推荐文章于 2024-12-18 00:00:00 发布

转载最新推荐文章于 2024-12-18 00:00:00 发布 · 87 阅读

（2）帧事件

框架也提供了帧事件，它在渲染过程中的每一帧被调用，应用程序应该注册并实现这些回调函数，如下表所示：

应用程序回调函数
注册回调函数
框架调用时机
场景渲染

LPDXUTCALLBACK-
FRAMEMOVE
DXUTSetCallback-
FrameMove
在每一帧开始时调用一次
这个回调函数是应用程序处理场景更新的最好位置，但它不应包括实际的渲染调用，渲染调用应放在帧渲染回调函数中。

LPDXUTCALLBACK-
D3D9FRAMERENDER
DXUTSetCallback-
D3D9FrameRender
在每一帧结束或窗口需要重画时调用
所有对场景的渲染调用都应在此回调函数中完成，在这个回调函数返回后，框架将调用Present()来显示交换链中下一缓冲区的内容。

DXUTSetCallbackFrameMove

Sets the frame update callback function.

VOID DXUTSetCallbackFrameMove(
LPDXUTCALLBACKFRAMEMOVE pCallbackFrameMove,
void* pUserContext
);

Parameters

pCallbackFrameMove

[in] Pointer to a LPDXUTCALLBACKFRAMEMOVE callback function. If the callback function is supplied, it will be called at the beginning of every frame to facilitate updates to the scene. If NULL, DXUT will not notify the application about new frames.

pUserContext

[in] Pointer to a user-defined value which is passed to the callback function. Typically used by an application to pass a pointer to a data structure that provides context information for the callback function. The default value is NULL

Return Values

No return value.

Remarks

The LPDXUTCALLBACKFRAMEMOVE callback function is the appropriate location for the application to handle updates to the scene. However, LPDXUTCALLBACKFRAMEMOVE is not intended to contain actual rendering calls, which should instead be placed in the LPDXUTCALLBACKD3D9FRAMERENDER or LPDXUTCALLBACKD3D10FRAMERENDER callback function. These callbacks is called when rendering with either Direct3D 9 or Direct3D 10 respectively.

The LPDXUTCALLBACKFRAMEMOVE callback function will be called once per frame, while the render callback function will be called whenever the scene needs to be rendered, which might be more than once per frame on rare occasion if a WM_PAINT message occurs.

LPDXUTCALLBACKFRAMEMOVE

Application-defined callback function that allows for updating the scene. This function is called by DXUT once each frame, before the application renders the scene.

VOID LPDXUTCALLBACKFRAMEMOVE(
DOUBLE fTime,
FLOAT fElapsedTime,
void* pUserContext
);

Parameters

fTime

[in] Time elapsed since the application started, in seconds.

fElapsedTime

[in] Time elapsed since the last frame, in seconds.

pUserContext

Return Values

No return value.

Remarks

DXUTSetCallbackD3D9FrameRender

Sets the Direct3D 9 frame render callback function.

VOID DXUTSetCallbackD3D9FrameRender(
LPDXUTCALLBACKD3D9FRAMERENDER pCallback,
void* pUserContext
);

Parameters

pCallback

[in] Pointer to a LPDXUTCALLBACKD3D9FRAMERENDER callback function. If the callback function is supplied, it will be called once per frame for the application to render the current scene using the Direct3D 9 device. If NULL, DXUT will not prompt the application to render the scene.

pUserContext

Return Values

No return value.

Remarks

This function only needs to be called if the application supports rendering with Direct3D 9 device.

The LPDXUTCALLBACKD3D9FRAMERENDER callback function is the appropriate location for the application to render the current scene using the Direct3D 9 device. The LPDXUTCALLBACKFRAMEMOVE callback function will be called once per frame, while LPDXUTCALLBACKD3D9FRAMERENDER will be called when the scene needs to be rendered, which might be more than once per frame.

LPDXUTCALLBACKD3D9FRAMERENDER

Application-defined callback function that allows for rendering the scene using a Direct3D 9 device. This function is called by DXUT at the end of every frame, and whenever the application needs to paint the scene.

VOID LPDXUTCALLBACKD3D9FRAMERENDER(
IDirect3DDevice9 * pd3dDevice,
DOUBLE fTime,
FLOAT fElapsedTime,
void* pUserContext
);

Parameters

pd3dDevice

[in] Pointer to the Direct3D 9 device used for rendering.

fTime

[in] Time elapsed since the application started, in seconds.

fElapsedTime

[in] Time elapsed since the last frame, in seconds.

pUserContext

Return Values

No return value.

Remarks

DXUT will call this function after the LPDXUTCALLBACKFRAMEMOVE callback function.

在函数LPDXUTCALLBACKFRAMEMOVE中，通常进行数据变换，比如设置坐标变换矩阵。在函数LPDXUTCALLBACKD3D9FRAMERENDER中，主要进行图形的渲染，类似于Direct3D API中的Render()函数。

（3）消息事件

框架通过下表中的回调函数和相应的注册函数来传递窗口消息、键盘事件和鼠标事件，编写应用程序对这些事件做出适当反应。

应用程序回调函数
注册回调函数
描述

LPDXUTCALLBACKMSGPROC
DXUTSetCallbackMsgProc
处理来自DXUT消息泵的窗口消息

LPDXUTCALLBACKKEYBOARD
DXUTSetCallbackKeyboard
处理来自DXUT消息泵的键盘事件

LPDXUTCALLBACKMOUSE
DXUTSetCallbackMouse
处理来自DXUT消息泵的鼠标事件

DXUTSetCallbackKeyboard

Sets the keyboard event callback function.

VOID DXUTSetCallbackKeyboard(
LPDXUTCALLBACKKEYBOARD pCallbackKeyboard,
void* pUserContext
);

Parameters

pCallbackKeyboard

[in] Pointer to a LPDXUTCALLBACKKEYBOARD keyboard event callback function. If supplied, the callback function will be called for keyboard events. If NULL, DXUT will not notify the application about keyboard events.

pUserContext

Return Values

No return value.

Remarks

The pCallbackKeyboard keyboard event callback function will be called when any keyboard event occurs.

This callback mechanism is provided to simplify handling keyboard messages through the windows message pump, but does not preclude the application from handling those messages directly through the LPDXUTCALLBACKMSGPROC callback.

LPDXUTCALLBACKKEYBOARD

Application-defined keyboard event callback function, called by DXUT.

VOID LPDXUTCALLBACKKEYBOARD(
UINT nChar,
bool bKeyDown,
bool bAltDown,
void* pUserContext
);

Parameters

nChar

[in] A virtual-key code for the key. See Virtual-Key Codes for a listing.

bKeyDown

[in] TRUE if key is down. FALSE if the key is up

bAltDown

[in] TRUE if the ALT key is also down.

pUserContext

Return Values

No return value.

Remarks

The pCallbackKeyboard keyboard event callback function will be called when any keyboard event occurs.

DXUTSetCallbackMouse

Sets the mouse event callback function.

VOID DXUTSetCallbackMouse(
LPDXUTCALLBACKMOUSE pCallbackMouse,
BOOL bIncludeMouseMove,
void* pUserContext
);

Parameters

pCallbackMouse

[in] Pointer to an LPDXUTCALLBACKMOUSE mouse event callback function. If supplied, the callback function will be called for mouse events. If NULL, DXUT will not notify the application about mouse events.

bIncludeMouseMove

[in] If TRUE, the mouse movement events are passed to the pCallbackMouse callback function. Default value is FALSE.

pUserContext

Return Values

No return value.

Remarks

The pCallbackMouse mouse event callback function will be called when any mouse events occurs

This callback mechanism is provided to simplify handling mouse messages through the Windows message pump, but does not preclude the application from handling those messages directly in the LPDXUTCALLBACKMSGPROC callback function.

LPDXUTCALLBACKMOUSE

Application-defined mouse event callback function, called by DXUT when it receives mouse events.

VOID LPDXUTCALLBACKMOUSE(
bool bLeftButtonDown,
bool bRightButtonDown,
bool bMiddleButtonDown,
bool bSideButton1Down,
bool bSideButton2Down,
INT nMouseWheelDelta,
INT xPos,
INT yPos,
void* pUserContext
);

Parameters

bLeftButtonDown

[in] The left mouse button is down.

bRightButtonDown

[in] The right mouse button is down.

bMiddleButtonDown

[in] The middle mouse button is down.

bSideButton1Down

[in] Windows 2000/Windows XP: The first side button is down.

bSideButton2Down

[in] Windows 2000/Windows XP: The second side button is down.

nMouseWheelDelta

[in] The distance and direction the mouse wheel has rolled, expressed in multiples or divisions of WHEEL_DELTA, which is 120. A positive value indicates that the wheel was rotated forward, away from the user; a negative value indicates that the wheel was rotated backward, toward the user.

xPos

[in] x-coordinate of the pointer, relative to the upper-left corner of the client area.

yPos

[in] y-coordinate of the pointer, relative to the upper-left corner of the client area.

pUserContext