Selecting objects.

[metachief]

Hello, I am working on R.T.S. and I can't figure out how to select oneobject a a time. What I mean is: I have 3 circles on the screen and I want to have one change color by selecting it with the mouse. I want it to be something like selecting units in warcraft for examle. I'm not having trouble with the visual part. I need the concept. What variales would I have as arrays and where will I use a for loop statement? Do I need to use types for each unit?

[lordroba]

An easy way to do it would be to set up an array with records

Turing:

var cUnit : array 1 .. 100 of     record         x : int         y : int         selected : boolean         hp : int         %and so on...     end record for i : 1 .. 100     cUnit (i).selected := false end for

I would initially declare all units as non selected, and then when you click on a unit, (you'd figure this out by their position on the map) you'd change that unit's selected value to true. for example cUnit(23).selected:=true Then you could use if conditions with that. Say for example...

Turing:

if cUnit(i).selected=true then %make that unit appear highlighted on screen

[metachief]

Well, you din't quite answer my question, but you gave me a better way of selecting single units (I had that covered, but using records is probably better so i'll try that)

The thing that I was having troubble with was selecting multiple units at the same time. I mean highliting them. You know how in warcraft you can select many of them by clicking on the mouse and dragging it to make a square over them and if they are in that square then they are selected. Well that is what I'm trying to do.
How do I figure out weither they are in the area of the squareor not?

[Tony]

metachief @ Thu May 08, 2008 9:46 am wrote:

How do I figure out weither they are in the area of the squareor not?

It's much easier to figure this out if you draw a rectangle on paper then hit random dots and ask yourself "is this inside?"

And no, "well it looks like it's inside" doesn't count. Try to work out a set of math rules that make the statement definitively true. (Things like "the point is to the left of this rectangle's side" or "the point is this far away from a vertex").

[lordroba]

needless to say, I was somewhat bored...

I copied the Mouse.ButtonWait code from the help files and changed the lines to boxes.
Basically with this code, it first checks from which direction the box is drawn, and then it checks if the circles are within that box...

Turing:

var cUnit : array 1 .. 10 of     record         x : int         y : int         selected : boolean         hp : int         %and so on...     end record for i : 1 .. 10     cUnit (i).selected := false end for cUnit (1).x := 110 cUnit (1).y := 110 cUnit (2).x := 120 cUnit (2).y := 20 cUnit (3).x := 30 cUnit (3).y := 130 for i : 1 .. 3     drawoval (cUnit (i).x, cUnit (i).y, 5, 5, 9) end for var x, y, btnNumber, btnUpDown, buttons : int var nx, ny : int loop     Mouse.ButtonWait ("down", x, y, btnNumber, btnUpDown)     nx := x     ny := y     loop         Draw.Box (x, y, nx, ny, 0)         % Erase previous line         exit when Mouse.ButtonMoved ("up")         Mouse.Where (nx, ny, buttons)         for i : 1 .. 3             drawoval (cUnit (i).x, cUnit (i).y, 5, 5, 9)         end for         Draw.Box (x, y, nx, ny, 1)        % Draw line to position     end loop     Mouse.ButtonWait ("up", nx, ny, btnNumber, btnUpDown)     Draw.Box (x, y, nx, ny, 2)         % Draw line to final position     for i : 1 .. 3         if nx > x then             if cUnit (i).x < nx and cUnit (i).x > x then                 if ny > y then                     if cUnit (i).y < ny and cUnit (i).y > y then                         cUnit (i).selected := true                     else                         cUnit (i).selected := false                     end if                 end if                 if ny < y then                     if cUnit (i).y > ny and cUnit (i).y < y then                         cUnit (i).selected := true                     else                         cUnit (i).selected := false                     end if                 end if             else                 cUnit (i).selected := false             end if         elsif nx < x then             if cUnit (i).x > nx and cUnit (i).x < x then                 if ny > y then                     if cUnit (i).y < ny and cUnit (i).y > y then                         cUnit (i).selected := true                     else                         cUnit (i).selected := false                     end if                 end if                 if ny < y then                     if cUnit (i).y > ny and cUnit (i).y < y then                         cUnit (i).selected := true                     else                         cUnit (i).selected := false                     end if                 end if             else                 cUnit (i).selected := false             end if         end if         cls         for v : 1 .. 3             if cUnit (v).selected = true then                 drawfilloval (cUnit (v).x, cUnit (v).y, 5, 5, 9)             else                 drawoval (cUnit (v).x, cUnit (v).y, 5, 5, 9)             end if         end for     end for end loop

if you draw a box somewhere else, your units will be deselected

[metachief]

Cool, I never heard of Muse.ButtonWait. Althought you would probably agree that that's a lot of code just to select units. Thanks anyway, but I'm going to try to figure out a more clear and efficient way. Perhaps after experimenting with equations i'll get it. If I do I'll inform you as well.