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

Warning: session_start() [function.session-start]: Cann.....
hi, can someone help me with this? I keep getting this error....

Warning: session_start() [fu

a very simple php header question (sorry!)
Firstly...I do apologise if this annoys anyone....a header error

I'm do not know php &

Schedule editor
Hi,

I have a question related to Schedule editor.
If we schedule a BLS for every 30

Problem assigning value to variable in "IF" function
Does this script makes sense? I am trying to take the value that is set to "authenticat" a

fopen() security
As i understood the usage of fopen() for it to function correctly the Dir you write to has to be rw

Google Wave
So... has anyone used it yet? Is it any good?

http://wave.google.com/help/wave/about.html#vid

php not working written for consumption of slots
1. Here is the function where i will be allowed to consume the slot booked by me.

2. Here i c

Help With Showing Users On the Index Page
Ive got this code which works just how i want it to.

Code: <?
$timenow=time();

Inserting multiple records from single form
I've found a number of threads that deal with this issue, but I'm new to php and coding language so

gather checkbox data from form into email
Hello all,

First, i'd like to thank everyone who responded to my previous posts regarding set

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