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General: Win32 Window creation
By: Jack Hoxley
Written: May 2000

Download: GM_Win32DLL.Zip (11kb)

When VB creates us a form it is basically simplifying the use of the MFC (Microsoft Foundation Classes) which C++ developers tend to use. This translation can be costly to our application. In C++ it is taken that the MFC shouldn't always be used in time critical programs; the same can be applied to us, but with something extra. Because VB translates everything for us it will take a little while for this translation to take place; which could be a little extra speed for our program. As well as this translation we are also using the MFC - effectively two potential slowdowns.

This makes it sound like using forms is a bad thing. For my argument to be of any use to you you'll have to be picky. I'm not saying that you'll see any great speed advantages; at best 2-5 fps on some computers. On top of this, you cant use controls so easily, and you can't add things into the forms events (such as Form_load and Form_Click) - which can be a real pain for some people. There is one last slight advantage; VB seems to compile smaller and possibly faster (a negligable increase) EXE. Especially when you use the method below.

Using no forms will only really be of advantage to the perfectionist, and those with a little more patience than the rest of us. Using this method is only really useful when it comes to using fullscreen graphics (DirectDraw or Direct3D) - as these dont rely heavily on controls or other items that forms offer us.

My method; and the way that this tutorial will demonstrate is through an ActiveX-VB DLL. This way we'll have all the form creation code (which is quite big) seperate of our main program - which makes the EXE simpler (see above). Putting this code into a DLL has two main advantages:

  1. Simplicity. It makes your master project (the EXE) much easier to look at. You could have 1000 lines of code in your project for creating a window; or you could link this DLL to your project and use it with 3-4 lines of code. It also makes your pogram easier to understand for other people, and yourself when you come back to it 6 monthes later. Which would you prefer?
  2. Reusabilty. Once this DLL has been written, debugged, checked, error corrected and compiled it can be used again and again. Everytime you want to create a window, just add a reference, stick a few lines of code in and off you go - nowhere near as complex as searching your hard drive for an odd module file; attaching it to your project etc... Also, if it is completely stable and has been thoroughly tested you KNOW it will work first time and every time.

The Sample
The sample file included is very basic - it uses very little of the potential provided by the Win32 Libraries. It is, however, perfectly suitable for use as a DirectDraw container window. With this you can create a complete DirectDraw project with one Module in your project. There are three very important things you must bare in mind first:

  1. DirectXevent. You can no longer use the DirectXEvent if you use this library. This isn't down to the way it is programmed; just a general side effect of using the Win32 Libraries. The DirectXEvent must be declared in a form object and cant be declared ina module or a class - therefore, if this DLL replaces the form object we cant declare a DirectXEvent.
  2. Stability. There were numerous stability issues when developing this DLL - although it seems to work fine all the time now I cant garauntee that it will be completely error free. Use it at your own risk; although if you do you're unlikely to get any errors.
  3. Using DirectInput. Because you no longer have access to the Form_KeyDown, Form_MouseDown (etc...) events you won't be able to stop your program using user input. You must use DirectInput (or the API equivelent) to get input from your user to close the program.

Having said all those bad things; try it - you may well find it to be useful. You can download it fromt he top of the page, or from the downloads page.

DirectX 4 VB 2000 Jack Hoxley. All rights reserved.
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