OpenGL depth buffer maximum distance

Since the depth buffer pixels can only have colors from 0 to 255 (am I right?), the maximum draw distance would be limited by that bounds as well.

• Is that tr开发者_Go百科ue?
• How do modern games work around this?
• What about values inbetween? Like 125.5?

• No its not true. Its usually not even possible to use an 8-bit depth buffer due to the limited range it would provide. The minimum is usually 16-bit with 24bit (saving the top 8 bits of 32 for a stencil buffer) the most common. Its also possible to use floating point depth buffers and 32-bit integer buffers.
• By using a greater depth.
• In the case of a value like 125.5 It would actually get rounded or truncated to 126 or 125. However in general through OpenGL you would actually pass a depth value of between 1 and -1 (post projection and w divide) to OpenGL. This value is then sent to the OpenGL run time which converts it to an actual depth value. This way you can change the bit depth of the depth buffer and everything continues to work.

Games that want to show a huge landscape usually use a skybox / skysphere, ie. a flat image which gives the impression of greatness.

I remember Guildwars' main menu. It looks huge, but it you look closely, it's really a round texture.

Depth buffer pixels are here to make sure objects which are rendered further than an existing object are not drawn. If two objects have the same depth, they can choose to render it anyway, or not; either way is fine, you don't look for this much precision.