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.

Did you know?Explore Trending and Topic pages for more stories like this.
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

Can anyone give me some link on .htaccess tutorial
i wish to have friendly url using .htaccess, but no idea yet about this

Hope that anyone cou

error checking breaking my code
Hi there, OK first of all, big apologies for what I assume is really fundamental errors in the struc

IS this code correct
The reason i ask is everything underneath it appears to be alink as well, tis blimmin annoying

Error: SQL Syntax; Line 1
Code:

<?php require "global_settings.php"; ?>
<title&g

help with database debug pls
Parse error: syntax error, unexpected T_ELSE in /home/content/m/e/s/mesick/html/students/05/php/chec

I need an iframe that calls up a different page according to the date
hi

I don't know any php (only html) and I urgently need to do the following:

I need a

try catch error
I have been trying try catch but, I can't get it to work. The code opens a non existing file called

Session problem?!?
Hello All! I am very new to the php world but I am working on fixing things that a previous programm

multiple recipients + dbuser mail recall
Hello,

I am building a php login script.

When the user registers the script will send

Error in Configure System Landscape Directory phase
Hi

We are getting the error in Configure SLD phase ( 41 of 44 phase).

Please f

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