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.

No comments posted yet

Your Answer:

Login to answer
213 Like 53 Dislike
Previous forums Next forums
Other forums

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

Format timestamp from mysql
When I tried this:
Code: date("m/d/Y H:i A", $row['timestamp'])
I got 12/31/1969 18:

php/xmlrpc class issue
I am working on xml-rpc in php to start with.

I have a class that only has variables defined

Code error with Index.php
Error: Parse error: syntax error, unexpected T_STRING, expecting ',' or ';' in /home/runevid/public_

upload image name with extension using php
hi frds..

<input id="file1" type="file" name="file[]" &a

getting rid of quotes in strings
sick of trying to deal with them in multiple ways (entering in and taking from database, echoing, ec

Querying info from one table based on info in another
Hi, I am currently trying to make a part for my user driven website where one user can subscribe to

PHP code needed to get/post form fields and request mysql query results.
I'm new to PHP

I've created an html form to allow the user to request a basic telephone dire

wav to mp3 + goDaddy
I need to convert wav files to mp3s. From what I have found so far one way to do it is to have my PH

Help With editting and deleting form
Hallo !!

So look at this image :

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

Sign up to write
Sign up now if you have flare of writing..
Login   |   Register
Follow Us
Indyaspeak @ Facebook Indyaspeak @ Twitter Indyaspeak @ Pinterest RSS



Play Free Quiz and Win Cash