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
How to give the privillege for triggers?
Hi,
How to give the privillage for triggers to particular user?
Please let me
PHP, Arrays & A Lot Of Confusion
I've been doing basic PHP work on sites for a few years now, but I've never been tempted to learn ho
simple php table loop
Hi all,
I've the following code
<?php // Create category options
INSERT data problem!
After having an string with apostrophes ', double quotes " or any other special characters, suc
xml
<?php
echo "<h1>XML Articles</h1>";
$home
Does design fit in FPGA ?
Hi all,
I've made a large HCC-Design. Because of the program-size the compile process with th
php or sql?
Sorry not sure if this is a sql problem or php the following code is supposed to delete data from th
Script not running properly
Hello Everyone
This is a basic script for posting to a database. I'm not sure why it doesn't work
PHP and MySQL Question/Help
I have a MySQL db with all my servers and all their details like server name, IP, OS, RAM etc etc 26
confused between ' ' and " "
there is a php i set:
$begin_date_query = mysql_query( "SELECT SUBDATE(due_date, INTERVAL $d