Introduction To Alpha Blending

最新推荐文章于 2021-07-12 17:28:57 发布

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本文介绍了Alpha混合技术在计算机图形学中的应用，通过调整透明度来实现前景与背景颜色的融合，创造出透明效果。Alpha混合技术广泛应用于显示玻璃或液体等透明物体的场景，并可用于动画中平滑地过渡两个图像。

Article by : Duane Bong

Introduction To Alpha Blending

Alpha blending is used in computer graphics to create the effect of transparency. This is useful in scenes that feature glass or liquid objects. It does this by combining a translucent foreground with a background colour to create an in-between blend. For animations, alpha blending can also be used to gradually fade one image into another.

Alpha Value Set To 0, 0.5 and 1

How Does Alpha Blending Work?

In computer graphics, an image uses 4 channels to define its colour. Three of these are the primary colour channels - red, green and blue. The fourth, known as the alpha channel, conveys information about the image抯 transparency. It specifies how foreground colours should be merged with those in the background when overlaid on top of each other.

The equation used in alpha blending is:

where [r,g,b] is the red, green, blue colour channels and alpha is the weighting factor.

In fact, it is from the weight factor, that alpha blending gets its name. The weighting factor is allowed to take any value from 0 to 1. When set to 0, the foreground is completely transparent. When it is set to 1, it becomes opaque and totally obscures the background. Any intermediate value creates a mixture of the two images.