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
53
Other forums
how to easy edit text, with box? Help.
Hi.
I have a little problem. I'm doing a webpage for my aunt and I would like to make it as easy
couldn't connect to your database
Hello I am new to php mysql
Actually i have read A tutorial on nettuts
"http://net.tu
Need understanding of this bit of code
Code: <?php
// WHERE clause filters
$arrSQLFilters = array();
//
Can I use a loop
Hi buddies!
Once again with my doubts here.
Right now I am using this sql stat
compile php5 with DOM
Hi,
I can't manage to compile php 5.3.0 from source on Windows to include DOM,
in spite of
very easy question about SQL info
Hello,
I think that I have a very easy question.
I know how to create a form using php SQL and
How can use this array as a key?
Say I have this array for example:
print_r($array);
Prints:
Code: [Select]Array
PECL uploadprogress for php5.2
Hey, I just installed PHP5 via .htaccess on my 1and1 Shared Hosting Account.
How would I exac
BSP Ext - tableView - Sort - NEWBIE
Hi,
I have been trying to get the sort to work. I have defined the column definitions by fillin
Error with Font and imagettfbbox
I keep getting an error that says "Warning: imagettfbbox() [function.imagettfbbox]: Could not f