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
Get last modified date of web page
Hai All,
In php how can i get last modified date of a give web page . I have tried to g
apart from cron
I need to run a php file every one hour. Is there any other solution apart from cron job?
Database/Table Collation
What is the Database, and table collations used for? i don't understand what there used for since co
Mysql error message
help me find out what this error message means:
"Duplicate entry '0' for key 'PRIMARY'&q
phpMailer will not connect using SMTP
I am trying to use phpMailer with smtp:
Code: [Select]$mailer = new PHPMailer();
$mailer-&
php include email form with attachment
I have had no luck with finding a email form all over the Internet for various reasons. Some insecur
passing an array of objects after submit
How do I do this? This is what I have tried and it is not working.
<form method="
Multithreading design
Hi
I have come up with a Singleton class that manages a pool of database connections. Basical
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
Secure FTP
Hi experts,
There is no SFTP action in MII workbench.
This means it needs developing custo
