Introduction
In the newsgroups there have been lots of questions about how to proceed with the initialization
in CD3DApplication (derived class CMyD3DApplication as you can see in most of samples).
Just to note: CD3DApplication class is main "root" component of 3D3DFramework - library
of usefull classes which is used by most of the Direct3D SDK samples, including original C++ and
ObjectPascal ones.
The following are some short notes that should help you understand what's going
on here. This has been submitted to the DX docs team for the basis of a revised explanation of
the sample framework in the next release of the docs (DirectX 9 timeframe).
Diagram
I hope this diagram will help you to see in whitch order functions are called and possible
transitions between them.
Legend:
- Plain green arrows show "normal" order in witch functions are called
- Circle arrow show what transition between FrameMove and Render could happen
million times (if app is still running)
- Curved arrows shows possible transitions when user (or other system processes) forsed your
application: change window size, exit fullscreen mode, change rendering device
Description
The following methods are all paired: one for initialization and one
for destruction. They represent the different phases of
initialization for a D3D application. The phases are as follows.
Delphi: Create, Destroy
C++: CMyD3DApplication, ~CMyD3Dapplication
Object constructor and destructor. Member variables should be
initialized to a known state here. The application window has not
yet been created and no Direct3D device has been created, so any
initialization that depends on a window or Direct3D should be
deferred to a later stage.
OneTimeSceneInit, FinalCleanup
The window has been created and the IDirect3D8 interface has been
created, but the device has not been created yet. Here you can
perform application-related initialization and cleanup that does
not depend on a device.
InitDeviceObjects, DeleteDeviceObjects
The device has been created. Resources that are not lost on
Reset() can be created here -- resources in D3DPOOL_MANAGED,
D3DPOOL_SCRATCH, or D3DPOOL_SYSTEMMEM. Image surfaces created via
CreateImageSurface are never lost and can be created here. Vertex
shaders and pixel shaders can also be created here as they are not
lost on Reset().
RestoreDeviceObjects, InvalidateDeviceObjects
The device exists, but may have just been Reset(). Resources in
D3DPOOL_DEFAULT and any other device state that persists during
rendering should be set here. Render states, matrices, textures,
etc., that don't change during rendering can be set once here to
avoid redundant state setting during Render() or FrameMove().
FrameMove, Render
Everything is created and we actually are running. FrameMove function should recalculate scene physics, and Render function - actually render it. This division has been done to allow user pause sample and still watch scene rendering.
Greetings
Most of this info (except diagram and some additions) was posted by
"Rich", frequent contributor of Direct3D
newsgroups and author of upcoming book on Direct3D from Addison-Wesley!
http://www.xmission.com/~legalize/book/
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