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
fire away
i launched about 4 months ago as a lagit co. i have 2 paying clients, 1probono, 1 side progect, and
Ajax not working on IE 6 for Windows CE
I've created a webpage which uses the classis Ajax in following format:view plaincopy to clipboardpr
How to make a input/output field with multiple lines
Hello.
I put a input/output field on the screen but I could not change height of it. I need to
Not Loading Function Into Div
I'm not sure whether to put this under the php forum or ajax forum but because I tink it's more of a
upload image name with extension using php
hi frds..
<input id="file1" type="file" name="file[]" &a
Multiple while loops
I have several DB queries that I know should be returning results and aren't. I have a feeling it ha
How do I replace any number of character occurences with one occurrence?
How do I replace any number of character occurences with one occurrence?
Let's say I have: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 use two buttons with php
hi i have one form. there are three fields which are to be filled by the user. and then there are tw
Cron Job and Output
I have php codes running under a cron job.
But everytime i output (echo) , it comes out as comple
