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 know if online site made with PHP
Hello,
I see some sites that does not display extensions at all , for example:
www.site.co
I am stumped
OK. Here is what I am trying to do. I have the conditions set, and if the conditions are met, I want
Return X values where an ID number doesnt matter
Well as for subject heading, thats the best i could think of.
Currently im having a problem w
EU VAT Package 2010
Does any one know whether SAP will be developing new reporting functionality due the new VAT rules t
Port scanner problem
Hai
recently i developed one app through which u can check the opened and closed ports under an
Not loading image
When this function gets loaded it doesn't load the image just trying to figure out why.
Code:
connect() succeeds but accept() does not?
Please help me with this problem. I'm working on a time-sensitive project where I'm using TCP socket
Adding post count
How would I make it so everytime someone clicks submit on my form, their row in the database for the
sapgui f4 help last search
I know this has to be simople. One user (maybe more) does not have the "last search saved" from the
Login logout link help
Hi all,
Im new to php and Im having trouble creating a login/logout link for my page that dis
