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
PHP5 - AJAX help
I've been following the tutorial on w2schools (http://www.w3schools.com/php/php_ajax_database.asp) a
how to query data from website using VC?
I want to query some datum from a website,so I need a program to read data from a .csv file, and ass
Warning: mysql_num_rows() supplied argument is not a valid MySQL result resource
This may be simple I just may need another pair of eyes..
When i get records back the below c
Table sorting
Hi,
I'm trying to modify the following in order to make the output table sorted alphabeticall
PHP Thumbnail Creation
Ok so i use this function to create thumbnails:
Code: [Select]function createthumb($name,$fil
Remove Rows From Database ad
Hi All,
I have this:
Code: [Select]<?php
session_start();
include('../com
WORDPRESS - Multiple Loops Only Going to One Post?
I have various pages with multiple loops and i need them to be individual to all other categories.Inserting the current date/time while submitting the forum
What do I need to add below to update the current date/time? I have a field in the database called d
Passing Variables
What I'm wanting to do is when the user clicks on Arenas it will know the name of the country it's w
frames get header location..
i have two frames, one top, one bottom. how do i do a form on the bottom frame that gives me the ur
