Q: What is Environment-Mapped Bump Mapping?

A: The next few times you wander out into your balcony, take a good look at the moon. Notice how it appears perfectly flat and smooth on some nights, while on others, you can clearly make out faint ridges, grooves, and dark spots-in other words, 'bumps'-on its surface?

To realistically transplant this moon onto your computer screen, and to recreate the illusion of such 'bumps' or variations of texture and depth, is no easy task in 3D graphics.

with EMBM  without EMBM
The same 3D model is shown with (left) and without (right) Environment Mapped Bump Mapping

Environment-Mapped Bump Mapping (EMBM) is a recent technique in the graphics industry that adds visual realism to 3D textures and objects by creating the illusion of bumps, or variations in surface depth, on an otherwise flat surface. A technique that has been a Microsoft® Direct3D® standard since the release of Microsoft® DirectX® 6.0 in 1998, this new 3D-rendering feature provides a simple way to accurately represent surface detail (or bumps) with more realism on a PC, than was ever possible before.

The idea behind the implementation of Environment-Mapped Bump Mapping is to use a "bump map" to define the variation or distortion of reflected light on the surface to which it's being mapped. EMBM enhances image quality by enabling four distinct new classes of visual effects (in 3D games, for example,) that are either impossible, or impractical, to achieve using other techniques. These effects include: surface bumps (think of tree barks or engravings), surface animations with reflections (water waves or ripples), surface animations and morphing (melting or skin regeneration), environment/ atmospheric distortion (heat shimmering or a lens effect).

Imagine being able to view fine details such as the pockmarked surface of bricks in a dungeon, scratches on robots and tanks, or special effects such as realistic water surfaces, heat shimmering off hot asphalt on a summer day, and air turbulence in flight simulators, all on your desktop!

EMBM is implemented through Microsoft's DirectX® 6.0 API. To support EMBM, a game developer simply needs to code a few DirectX 6 render states and texture stages, in addition to creating a bump map for each texture that represents height or depth of each pixel of the texture.

Further, both your computer graphics hardware, as well as the software you are running, needs to support DirectX6 Environment-Mapped Bump Mapping.

Which means you not only need to be playing the right EMBM-enabled 3D game but also have installed a graphics card featuring EMBM support, to experience a virtual moon on your PC that looks every bit as 'bumpy' as the real one.

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