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.
SQL query not working well
Hi,
I made a small table with 5 rows and want to make them an sql consult using rownum
Php WordPress help
I am writing the following code for making a plugin
<?php
header("Content-Type
Cron Job and Output
I have php codes running under a cron job.
But everytime i output (echo) , it comes out as comple
Losing 'page' data
I have this code that allows me to update my database. But after updating, I lose the $_GET['page']
Having a problem get the selected item from a drop down menu
I have been looking at this for days now.
I have a drop down menu that get it's values from a
preg_match logical error
Code: <?php
$s = file_get_contents("page.html");
preg_match('/<div cla
Creating an invoice
Using fpdf I am trying to create an invoice to send to clients. The products are sold in pricing tie
CURL XML Request [From C to PHP]
Hi,
I need some help converting this into something that will work with PHP.
Code: #
mysql_affected_rows() usage
Possibly a MySQL issue, but the function that is not behaving in the anticipated way is a PHP functi
Linking with Foreign Keys
I have been getting an erro when I try and link:
create table Faculty_Specialty (I_Name v
