[gameprogrammer] Re: weir cast problem in 64 bits system
- From: Roger Durañona <luo_hei@xxxxxxxx>
- To: gameprogrammer@xxxxxxxxxxxxx
- Date: Tue, 22 Jul 2008 10:38:58 -0400
Madison McGaffin escribió:
On 7/22/08, *Roger Durañona* <luo_hei@xxxxxxxx
<mailto:luo_hei@xxxxxxxx>> wrote:
Im trying to use Cal3d in my project and I have found a weird
problem. Cal3d API returns some values as void*, that should be
casted to GLint like this:
glBindTexture(GL_TEXTURE_2D, (GLint)pCalRenderer->getMapUserData(0));
This works on some systems but in others the compiler produces an
error: cast from void* to GLint loses precision. The only common
thing I can find between the 2 setups where I get the error is
that they are both 64 bits systems (Ubuntu and Gentoo).
Can someboy suggest me a solution for this, or at least the cause
of the problem?
What distinguishes a 64 bit system from a 32 bit system is that a 64
bit system can handle memory addresses identified by 64-bit data types
instead of just 32-bit data types. So, on 32 bit systems, void* is a
32-bit-wide pointer to some place in memory but on 64 bit systems, a
void* can be 64 bits wide. Most likely, GLint is fixed at 32 bits
wide, and, most likely, you shouldn't need to worry about the loss of
precision.
'course I don't know much about Cal3d specifically, and it seems
really horrible that they expect you to cast from a void* to a GLint,
but that's my 2c.
Thats what I read. But there must be some way to solve this problem,
because Eternal Lands uses Cal3d and they have both a 32 and 64 bits
version.
--
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Dios dijo , "Sea Newton" y todo fue luz", Alexander Pope
"Pero esto no fue lo último. El diablo gritó "Sea Einstein",
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