Poster: Iriel at 10/16/2005 5:43:05 PM PDT
Subject: Solution to drawing some of a ring |
| |
So I sat down to figure out how to draw a partial ring within WoW, and ended up a with a much nicer solution than the angled mask approach. I'll be releasing some example code with it in once I finish it off and clean it up, but I figured I'd explain what I came up with.
This approach requires two texture files, and six texture objects.
File 1: A ring quadrant
File 2: A 45 degree sliced square.
It's easiest to explain this with just a single quadrant, so let's consider the top right quadrant of the ring, and an angle A, where 0 is no visible ring, and it increases from the top down to the right (Like a clock).
The top left hand corner of this quadrant (the 'noon' position), we'll call N (Nx,Ny)
The line from the center of the ring at angle A hits the inner edge of the ring at point I (Ix,Iy), and the outer edge of the ring at point O (Ox, Oy).
For a ring of inner and outer radius IR, and OR, those points are:
Nx = 0, Ny = OR
Ix = IR * sin(A), Iy = IR * cos(A)
Ox = OR * sin(A), Oy = OR * cos(A)
Angles up to 45 degrees
First draw the rectangular subset of the ring from the top left corner, down to point I, the intersection with the inner edge of the ring. This is your desired ring segment with a triangularish section chopped off the end to the right.
Next draw the rectangular 'chip' from the top right corner of the piece you just drew, down to point O, the outer edge of the ring. This fills in the curved outer edge that was missing.
This leaves a missing triangular section that represents where the angle slices across the ring. Stretch the 45 degree slice texture across that between points I and O.
So, to summarize:
Draw ring subset N=(Nx, Ny) to I=(Ix, Iy)
Draw ring subset (Ix, Ny) to O=(Ox, Oy)
Stretch slice between I=(Ix, Iy) and O=(Ox, Oy)
Angles from 45 degrees
This is different simply to keep the first rendered piece as significant as possible.
First draw the rectangular subset of the ring from the top left corner, down to point O, the intersection with the outer edge of the ring. This is your desired ring segment with a triangularish section chopped off the end to the bottom.
Next draw the rectangular 'chip' from the bottom left corner of the piece you just drew, over to point I, the inner edge of the ring. This fills in the curved inner edge that was missing.
This leaves a missing triangular section that represents where the angle slices across the ring. Stretch the 45 degree slice texture across that between points I and O.
So, to summarize:
Draw ring subset N=(Nx, Ny) to O=(Ox, Oy)
Draw ring subset (Nx, Oy) to I=(Ix, Iy)
Stretch slice between I=(Ix, Iy) and O=(Ox, Oy)
Completing the circle
This can be applied to the other quadrants by mirroring and/or swapping the X and Y coordinates, and textures. For a full circle subset you need 6 texture objects, the three discussed here for the active quadrant, and then three more (all set to the ring texture) for the three other 'full' quadrants for a full ring.
An arbitrary ring subset (rather than starting at the noon position) would require an adittional two or three textures (one more chip, one more slice, and possibly one more ring subset, if the ring angle is able to be larger than 270 degrees)[ post edited by Iriel ]
<Addon Authors: Dont use RegisterForSave()!>
| | | http://forums.worldofwarcraft.com/thread.aspx?fn=wow-interface-customization&t=245792&p=#post245792 | | | Poster: slouken at 10/16/2005 9:26:00 PM PDT
Subject: Re: Solution to drawing some of a ring |
| |
Very cool, Iriel. :)
| | | http://forums.worldofwarcraft.com/thread.aspx?fn=wow-interface-customization&t=245792&p=#post245924 | Poster: slouken at 10/16/2005 10:03:23 PM PDT
Subject: Re: Solution to drawing some of a ring |
| |
Q u o t e:
I do have one question about the frame layout engine, does it re-evaluate all of the anchors every frame, or does it only do those which have changed? Similarly are :Show() and :Hide() smart enough to be a fast exit if the frame in question is already visible/invisible? I ask because I'm wondering if I need to store state to avoid redundant calls to those or not.
SetPoint() causes the layout engine to reevaluate the layout for that frame every update it's called (though multiple calls on a single frame in a single update don't add much)
Show() and Hide() are smart and don't do any work if they're already in that state.
| | | http://forums.worldofwarcraft.com/thread.aspx?fn=wow-interface-customization&t=245792&p=#post245953 | Poster: slouken at 10/17/2005 11:27:34 AM PDT
Subject: Re: Solution to drawing some of a ring |
| |
Q u o t e:
great, because some parts are wague to me even with those comments about the process :)
It helps alot to pick up pencil and paper and sketch out what Iriel is describing in the first post.
Edit: Remember, UI textures are rectangular. :)[ post edited by slouken ]
| | | http://forums.worldofwarcraft.com/thread.aspx?fn=wow-interface-customization&t=245792&p=#post246350 |
View all recent official Blue Posts
|
