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
gather checkbox data from form into email
Hello all,
First, i'd like to thank everyone who responded to my previous posts regarding set
How to Handle more than one submit button in single form?
Hi
I have one PHP file which contains one Form. In this form there are two Submit type Buttons
Extract specific information from a PHP Multidimensional Array
Howdy! I've racked my brain over this for 24 hours now. I think it's time I asked for help. I'm lear
Slashes
Have a small problem and I'm not able to understand why I'm getting the results I'm getting... and i
Unexpected T_Variable ?
Hi all,
I dont really know what I am doing!! I know I'm doing something wrong, and I know its on
Display last record first.
I need some help how put the last record first and first record last.
Thanks
Code: &am
Month String to Numeric?
Hi guys,
Given a month as a string, is there a simple way to find the numeric representation
Bit manipulation program with binary operations
My homework is to create a program to scan in and add binary numbers and print them like so
Update Myspace status with CURL
Logging in:
Code: <?php
class Myspace
{
function login($username, $pa
Error with Font and imagettfbbox
I keep getting an error that says "Warning: imagettfbbox() [function.imagettfbbox]: Could not f