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
53
Other forums
Agency Business Process
Hi,
I don’t understand the process of the agency business in SAP.
In my
Looking for help reading a .txt or .ini file and outputting the info.
I have a file called Info.ini and It has the following info:
Code: [General]
Online=0
I wou
Need Help with a query
Hello,
For some reason I am just not getting the right answer when I do this query and not quite
user administration
Dear @all,
what I have to do to set the user defaults for new users. At the moment I woul
Warning message
I've put a website that I was doing live and I'm getting this warning message when I try to add a ne
values not being entered into table
hi. I;ve created a form, so that when a user enters data into it, it gets added to a table in a data
Need Reporting Advice
My SQL server doesn't support MS SQL reporting services that comes with SQL Enterprise or Express. T
ScriptManager History and Opera Issue
I am having an issue in opera with the ScriptManager. I have a ScriptManager on a page with history
Remove values in array2 from array1
I have two arrays.
Array 1 is where the array key holds various different numbers. For exampl
asp authentication problem
Hello all,
I want to use the asp authentication (from asp.net configuration) in my web site. there