Thread: colorkeying
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Old 11-06-2009, 12:04 PM
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Joseph Koss

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if I remember correctly, most video cards did not support color keying of a range of values but instead only a single value.

Microsoft had been trying to get video card makers to support directdraw alpha blending as well, and that didn't become widely implemented either.

For Direct3D, alpha blending DID take off, so multi-color keying was left on the backburner as something not terribly important, since the image data can easily contain per-pixel alpha information which is even more versatile than color keying.

Single-color color keying is still widely supported because Direct Draw Overlays requires it, as most hardware accelerated video players absolutely require Direct Draw Overlays (even our "hardware mouse cursor" requires it)
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