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
Attempt to assign property of non-object in...
I'm having issues with the following function in PHP 5...
function getTreeWithChildre
PHP/Database issue
My friend is helping me make a database where you go to a certain webpage of my site and the page wi
send message to the java application
Oracle 10g with Windows platform.
I have a java application that periodically pings the d
Error when call dll from oracle
Hi all, please help me!
I have dll write C language, I want call it from oracle procedur
Grabbing Values From an Array for Posting
I have a grid array that I am using with a form that when it hits the currently named test.php it lo
temporary objects
Until now i thought every temporary object in C++ is created as constant. I'm wondering why my compi
adding 0 to numbers
Hey guys i need to create a 00001 number in a loop. Is there a better way of forcing a 5 digit numbe
Number Format
Hi All,
I have number '000000000050085' I want to format it to 500.85 Can any one give me
URL Rewrite issue
Im created a series of Rewrites and on page checks to make sure the correct url is being called. But
Transport data between itab and textfield on ALV event
Hallo,
I have a ALV Grid ( cl_gui_alv_grid ) and I also have hotspot click event with a h