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 calculate
this code echoes correctly the sum but the inserted result is 0??
Code: <?php
$TotalNum
PHP Error
On my .php page I have a drop down box that has several names in it. When a user clicks the name &am
Extracting Long text from message class with parameters
Hi,
I would like to extract the long text from a message class. However, the long text ha
Product categories for registration
Dear all,
We are going live with the Supplier registered next week. At standard, the 'sel
Sending UDP Raw socket
I truly need help on this. I am trying to write a test program that simulate a network environment
Last character removed
I have created a string from an array. I have inserted commas from my form values. I am trying to re
IDOC error
Hi,
When i send IDOC from ECC system to MII there is no problem ECC side, i says message sent succe
[PHP HELP] Php order form.
Hello to everyone @ phpfreaks. Im new to this site and hope to learn lots of things here.
Fir
Unifying logins of two different scripts
I have two different game scripts which I want to embed on my own site. The problem is I don't want
How to return to a previous page after running a PHP script
I'm having a bit of a melt down here because I think this should be really easy but can't work it ou
