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

Images outside webroot
Im hopeing someone can help me with this because i cant figure it out.I have setup an ASP.NET websit

PHP5/Zend 2.0 - Resources
PHP5 Snapshots
http://snaps.php.net/

ZEND 2.0 Feature Overview and Design (PDF File

php calculate
this code echoes correctly the sum but the inserted result is 0??
Code: <?php
$TotalNum

Question about the upload of large files
Hi there,

I have a question about the upload of large files, like videos (files generally abo

Line break?
Hi, I'm new to the forum and new to php. I'm not sure if I'm using the correct terminology so here i

help with contest script
I would like to code a contest script to my site but i don't know how. Could someone just give me pu

how do i make a string??
hey guys,
can someone please tell me how to put data from the glob function into a string

How to get exact 3 moths post date from today date using javascript
How to get exact 3 moths post date from today date using javascript
Please help

Can't get the unicode character
I'm trying to get some text from various parts of a file. I have converted the file to hex (bin2hex)

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

Warning: session_start() [fu