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Switching Modes While Running

Ah, we finally get to switching modes…

Well, we'll use a single function to switch modes. It'll be capable of changing between exclusive and windowed, and setting the display mode (while in exclusive mode). Here it is:

void ChangeDisplayMode(bool bExclusive,
      int nWidth, int nHeight, int nBPP);

Kind of simple, isn't it? No, well…I'll explain it a little. When you want to switch from exclusive mode to windowed mode, you call it like this:

ChangeDisplayMode(false, 0, 0, 0);  // windowed

When you want to switch to exclusive mode, or just change between resolutions and color depths, you call it like this:

ChangeDisplayMode(true, 640, 480, 16);  // 640x480x16 exclusive
ChangeDisplayMode(true, 800, 600, 32);  // 800x600x32 exclusive

Not bad, huh? Ok, let's flesh it out a little. Here's the whole function:

ChangeDisplayMode(bool bExclusive, int nWidth, int nHeight, int nBPP)
{
    // destroy any existing surfaces and clippers.
    DestroySurfaces();

    // create new surfaces and change the 
    // cooperative level and display mode
    CreateSurfaces(bExclusive, int nWidth, int nHeight, int nBPP);
}

That's it for switching modes!

There are lots of ways to wring more performance out of a windowed mode DirectX app. There are also a few ways to make it easier for the end user to use. We'll try to achieve a blend of both. You'll have to wait for the next article for those tips though!

Good Luck!

- null_pointer
e-mail: ratt96963@aol.com
web site: http://www.freeyellow.com/members8/nullpointer
site name: Sabre Multimedia