[Lazarus] TOpenGLControl.DepthBits default value
michalis.kambi at gmail.com
Wed Jan 23 00:21:44 CET 2013
Reimar Grabowski wrote:
> the in the topic mentioned property defaults to a value of 16. Is
> there any special reason for it? IMHO the default value should be 24.
> After all it's 2013 and not 1998.
> It's not really a problem, I just want to know the reason why this
> value was chosen.
Before my patch on http://bugs.freepascal.org/view.php?id=22170 the
depth bits were hardcoded (16 on WinAPI and 1 on GLX). So I set the
default value for TOpenGLControl.DepthBits at safe 16.
The general idea is that TOpenGLControl has safe default values, that
are guaranteed to work (and be fast) even on really really ancient
graphic cards or when the system is running under virtual machine (which
often means you don't get hardware-accelarated 3D until you explicitly
install/enable something). For the same reason e.g.
TOpenGLControl.StencilBits is by default 0, even though all modern GPUs
can give you at least 8-bit stencil buffer.
Other APIs to get OpenGL context, like GtkGLExt or Glut or low-level
WinAPI or GLX follow the same convention. The defaults are very
That said, I would be personally fine with changing this default to 24,
if others think it's a good idea. A developer can always lower it to 16
when that's enough. So, I don't really have a strong preference about it.
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