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
PHP MySQL and DATE
Hi everyone
I have a databse and in one of the columns I have date values such as 2009-March-
Problem assigning value to variable in "IF" function
Does this script makes sense? I am trying to take the value that is set to "authenticat" a
Allowing ' and "
Hello everyone,
I am creating a form where users submit information to go into a database. I
IIS & NW MII on the same server
Hi,
We're weighing the possibility to run both IIS and MII (NetWeaver) on the same server
The repetition structure: the while statement not working
New programming student, have assignment as follows:
A restaurant has 4 lunch combos for custom
Help with some dates
I have a list of dates in an array:
$mondays = array(
strtotime("October 12, 2009
Phase Error I can't seem to find :(`
Hey guys, I can seem to find my phase error on this. I am getting this error
[error]
Pars
Cannot Connect to Database
I am writing an application to do annual reviews. I cannot get my script to work. Whenever it runs I
gather checkbox data from form into email
Hello all,
First, i'd like to thank everyone who responded to my previous posts regarding set
Pagination
Hi All,
I think I'm finally getting somewhere with pagination!
I can now submit a quer