//-----------------------------------------------------------------------------
//
// Sample Name: WindowedMode Sample
//
// Copyright (c) 1999-2001 Microsoft Corporation. All rights reserved.
//
//-----------------------------------------------------------------------------
Description
===========
WindowedMode demonstrates the tasks required to initialize and run
a windowed DirectDraw application.
Path
====
Source: DXSDK\Samples\Multimedia\DDraw\WindowedMode
Executable: DXSDK\Samples\Multimedia\DDraw\Bin
User's Guide
============
WindowedMode requires no user input. Press the ESC key to quit the program.
Programming Notes
=================
The basic tasks to author a simple windowed DirectDraw application are as follows:
Initialize DirectDraw:
1. Register a window class and create a window.
2. Call DirectDrawCreateEx to create a DirectDraw object
3. Call SetCooperativeLevel to set the DirectDraw cooperative level
to normal.
4. Call CreateSurface to obtain a pointer to the primary surface. In windowed mode,
the primary surface is also the desktop window. So the pixel format for the
primary surface is based on the user's selection of display resolution.
5. Create a back-buffer. In windowed mode, this is should be an off-screen
plain buffer. The back buffer is typically the same size as the window's
client rect, but could be created with any size.
6. Test to see if the display mode is in palettized color (8-bit or less).
If it is then a palette needs to be created. This sample displays a single
bitmap so it can read the bitmap palette info to read and create a DirectDraw
palette. After a palette is created, call SetPalette to set the palette for
the primary surface.
7. Call CreateClipper and SetClipper to create a clipper object, and attach it
to the primary surface. This will keep DirectDraw from blting on top of
any windows which happen to overlap.
8. Create an off-screen plain DirectDraw surface, and load media content into it.
For example, this sample calls DDUtil_CreateSurfaceFromBitmap() to do just
this.
When the app is idle, and it is not hidden or minimized then render the
next frame by:
1. If movement or animation is involved in the app, then calculate how much
time has passed since the last time the frame was displayed.
2. Move or animate the app state based on how much time has passed.
3. Draw the current state into the off-screen plain backbuffer.
4. Call Blt to blt the contents of the off-screen plain backbuffer into
the primary surface.
If the display resolution changes or an exclusive mode DirectDraw app is run, then
the DirectDraw surface may be lost (resulting in a DirectDraw call returning
DDERR_SURFACELOST), then handle it by:
1. Call RestoreAllSurfaces to have DirectDraw restore all the surfaces.
2. Restoring a surface doesn't reload any content that existed in the surface
prior to it being lost. So you must now redraw the graphics the surfaces
once held. For example, this sample handles this by calling
DDUtil_ReDrawBitmapOnDDS()
In windowed mode, handle the following windows messages:
1. WM_PAINT: This is sent when all or a part of the window is needs to be
redrawn. The app may not be active at the time this is called, so if this
is not handled then the window will appear blank. To avoid this, make a
call to draw the next frame here.
2. WM_QUERYNEWPALETTE: This is sent when in a 8-bit desktop and the another
window set a new palette, but now this window has control so it needs to reset
its palette. The easy way to make this happen in DirectDraw is just to call
SetPalette. This will force DirectDraw to realize the DirectDrawPalette
attached to it.
3. WM_MOVE: This is sent when the window is moving. Record the new window position
here since the blt to the primary surface needs to know the window position.
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