Floating Point Precision Loss

Posted on 16th Feb 2014 07:03 pm by admin

I'm writing a program to draw a three-dimensional cube (with a corner cut off) without using any 3D graphics APIs. The only API call I make is win32's SetPixel()

Everything is going great. I've drawn lines, faces, and even the entire cube. Then rotation came along.

For some reason, when I rotate my cube, it begins to shrink. I became confused, then I realised something. Floating point numbers are truncated.

Here's some code that is fired everytime the user presses 'X' on the keyboard.

Code: p->setY( p->getY() * cos(5.0/180.0*PI) - p->getZ() * sin(5.0/180.0*PI)); p->setZ( p->getY() * sin(5.0/180.0*PI) + p->getZ() * cos(5.0/180.0*PI));

p is a Point object that I created. Here the Y value and the Z value of the Point are being set. The problem is everytime X is pressed, and this code is fired, a small amount of precision is lost. As a result, the cube shrinks.

I'm really completely stumped. I remember when studying assembler that floating point numbers can be truncated or rounded. I think rounding would solve my problem. Since 50% of the time the value would round up, and 50% of the time the value would round down.

Whereas with truncation values are always lost, and never gained.

Your Answer:

Login to answer

Other forums

Conditions of info record - Error
When i created GR (901) and PO create automatic my PBXX is obtain the net price of info record but

Any decent php formatter/beautifier/pretty printer?
Any decent php formatter/beautifier/pretty printer class/function?

I found the following whil

Error Messaging not working
I changed the way my form tells the user of an error. But I can't seem to get it to work properly.

Upload simple problem
Really confused!! I run once and it worked, but when i tried today...it didn't work

Which par

Tree Menu
Hi guys,

Can anyone help me making a tree navigation system? I have a site where I'm allowin

Form errors in an array
I'm processing a form and putting the errors in an array. empty($errors) doesn't seem to do the tric

Functions Not Loading Into Div
I had some help doing some of this but what I'm trying to do is get my functions to retrieve its val

cURL Upload Help
OK, I am creating a bridge from a local program to my website and I am trying to find the best way t

C++ Http request?
Code: string Response = "LOGIN_UNSUCCESSFUL"; System.Net.WebRequest request = Sy

Operating System
How in PHP or other language can I detect Operating system, ie Windows XP Home, Windows 7 Ultimate,