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a problem about Shape:getBoundingBox( ) in WIKI

Posted: Wed Jun 30, 2010 2:02 pm
by poorenglish
Hello;
In the wiki the Shape:getBoundingBox( ) description is "x1, y1, x2, y2, x3, y3, x4, y4 = Shape:getBoundingBox( )
Vertexes are returned starting in the top-left in a counterclockwise fashion (top-left, bottom-left, bottom-right, top-right)"
--http://love2d.org/wiki/Shape:getBoundingBox
I found in the "Tutorial:Physics" use this function.--http://love2d.org/wiki/Tutorial:Physics
Actually the "Vertexes are returned starting in the bottom-left in a clockwise fashion(bottom-left,top-left,top-right,bottom-right)
Is this a mistake for the wiki?
Thks

Re: a problem about Shape:getBoundingBox( ) in WIKI

Posted: Wed Jun 30, 2010 2:32 pm
by bartbes
I think the docs are right.

Re: a problem about Shape:getBoundingBox( ) in WIKI

Posted: Wed Jun 30, 2010 3:11 pm
by kikito
I suspect the this is another of those issues that come from the way LÖVE interprets the "y" coordinate when drawing - opposite as the "natural" (call it whatever you want) way to interpret it.

I'm not saying that LÖVE's way should be corrected, mind you; I'm just saying that its peculiarities must be taken into account. I had this same problem myself.

When I first read "Top" I assumed it meant "higher on the screen". I then learnt that it meant "the maximum <<y>> value", which is the opposite when drawing. This leads to a lot of interesting surprises; clockwise gets transformed in counter-clockwise.

The same goes for "Bottom"; they are kind of misleading words on this context.

I propose changing the documentation so all the "Top" and "Bottom" read "Maximum y" and "Minimum y" instead.

Re: a problem about Shape:getBoundingBox( ) in WIKI

Posted: Wed Jun 30, 2010 3:47 pm
by bartbes
That explains a lot.. now that I think of it that might be the problem.

Re: a problem about Shape:getBoundingBox( ) in WIKI

Posted: Thu Jul 01, 2010 12:23 pm
by poorenglish
Yes,I understand it。
It is different understanding about the "bottom" and "top".
111.JPG
111.JPG (4.18 KiB) Viewed 2151 times
If OK,I will add this picture into wiki for this function,remind others not muddle

Re: a problem about Shape:getBoundingBox( ) in WIKI

Posted: Thu Jul 01, 2010 1:36 pm
by TechnoCat

Re: a problem about Shape:getBoundingBox( ) in WIKI

Posted: Thu Jul 01, 2010 1:40 pm
by Maggots
Vertexes are returned starting in the top-left in a counterclockwise fashion (top-left, bottom-left, bottom-right, top-right).

That isn't right. :| When will it be changed?

Re: a problem about Shape:getBoundingBox( ) in WIKI

Posted: Thu Jul 01, 2010 7:45 pm
by TechnoCat
Maggots wrote:Vertexes are returned starting in the top-left in a counterclockwise fashion (top-left, bottom-left, bottom-right, top-right).

That isn't right. :| When will it be changed?
You tell me http://love2d.org/w/index.php?title=Sha ... ction=edit

Re: a problem about Shape:getBoundingBox( ) in WIKI

Posted: Thu Jul 01, 2010 8:06 pm
by Robin
I fixed it, you lazy farts! :P