Introduction to DirectX and Direct Draw

Made By Arsalan Aslam
Webmaster of Code Master

This tutorial assumes that you are using DirectX 7

DirectX is the a set of libraries which was developed by Microsoft for the game/graphic programmers. I will not go into further detail of how it works or blah blah.

Now if you want to program DirectX based games in VB you must remember few essential things.

1. First you must reference the DirectX library in your VB project.
2. All the DirectX components such as Direct Draw (DDraw), Direct 3D (D3D), etc are created from DirectX 7 object

This tutorial covers basic concept of DDraw. DirectDraw is a software interface that provides direct access to display devices while maintaining compatibility with the Windows graphics device interface. DDraw is mainly used to draw 2D graphics such as tiles, 2D sprites, etc.

1. All DDraw objects are created from DirectX7 object
2. It can have different number of surfaces in which pictures are drawn
3. All the surface must be defined before creation

Usually primary surface is the main surface on which the picture is displayed. For smoother drawing the picture is first drawn in the back buffer, then copied to the primary surface.

Why Use DirectDraw ? (From DirectX 7 SDK)

The DirectDraw component brings many powerful features to you, the Windows graphics programmer:

• The hardware abstraction layer (HAL) of DirectDraw provides a consistent interface through which to work directly with the display hardware, getting maximum performance.
• DirectDraw assesses the video hardware's capabilities, making use of special hardware features whenever possible. For example, if your video card supports hardware blitting, DirectDraw delegates blits to the video card, greatly increasing performance. Additionally, DirectDraw provides a hardware emulation layer (HEL) to support features when the hardware does not.
• DirectDraw exists under Windows, gaining the advantage of 32-bit memory addressing and a flat memory model that the operating system provides. DirectDraw presents video and system memory as large blocks of storage, not as small segments. If you've ever used segment:offset addressing, you will quickly begin to appreciate this "flat" memory model.
• DirectDraw makes it easy for you to implement page flipping with multiple back buffers in full-screen applications. For more information, see Page Flipping and Back Buffering.
• Support for clipping in windowed or full-screen applications.
• Support for 3-D z-buffers.
• Support for hardware-assisted overlays with z-ordering.
• Access to image-stretching hardware.
• Simultaneous access to standard and enhanced display-device memory areas.
• Other features include custom and dynamic palettes, exclusive hardware access, and resolution switching.

These features combine to make it possible for you to write applications that easily outperform standard Windows GDI-based applications and even MS-DOS applications.

Now examine the included source code for full details