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

Help With editting and deleting form
Hallo !!

So look at this image :

http://img194.imageshack.us/img194/8272/snapshot5f.pn

Form submissing with PHP and JQuery/Ajax
I have searched everywhere, but cannot find a solution for this... I have worked all day trying to g

I need desperate help with this php code integrated with flash please
Can someone please help me with this php code which I have been stuck on for weeks . I am trying to

User information
Hi All,
By using t-code SUIM we get all the user details,if suppose we donot have permission t

Saas with SAP R/3
hi experts,

Is SaaS offer available in SAP? for SAP R/3? from where i can get the info a

Connection Timeout
I'm using xmii 12.0

I'm calling a transaction as a web service from a windows application

code help - pagination
Hi all, I have this code, basically a user logs into my site and they get this page.

The pro

Save username into DB
OkaY so I got my blog to actually save the posts and whatever, all I need now is for it to keep the

Not "Just Another" MMORPG - text based.
Hello,

I've been learning MySQL and PHP for the last 2-3 years.
Though, I've had long paus

get multiple rows
Hi I want to get multiple rows from a db

I am using this for the db query
Code: public