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
Checkbox info wont include in Mailto
Hey, im new to php.
Basically I have made a form to request which type of job(s) are needed, whic
Form submissing with PHP and JQuery/Ajax
I have searched everywhere, but cannot find a solution for this... I have worked all day trying to g
re calling a function without including file
Hi,
i am new to programming in php, i was just checking the wordpress code and found out in the w
how to read and write into a word document using php...?
hi,
I need,reading and writting into a word document using php.
Thank u inadva
ECC6 - Single sign-on
We are in the process of upgrading to ECC 6 which will support single sign on with user passwords al
Progress bar for webpage
Hi,
I want to implement a progress/waiting bar on my webpage - exactly the same thing that the Mi
Using Microsoft Exchange Server with PHP
Hi,
I wanted to know if its possible to fetch email attachments from the exchange server usin
db entry based on primary key
My "topics" table contains 10 entires
*--------------*
topicid topic
------
registration form
first time posting. did some searches but didnt find exactly what i am looking for. dont flame cause
xApp Analytics in BI 7.0
Dear all,
I am trying to implement xApp Analytics in BI 7.0. After I installed the analyt
