Isometric Engine Problem

Well, calculating the tile it's over is not that hard, in this case:

Code:

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tileX = int (mouseX / 62)
tileY = int (mouseY / 29)
relativeX = mouseX - (tileX * 62)
relativeY = mouseY - (tileY * 29)

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Now tileX and tileY are the coordinates of the tile, and relativeX and relativeY is the position within that tile.

Wouldn't that only work for a flat grid, as opposed to isometric, where the tiles are not arranged vertically and horizontally?

You are right, my bad, didn't look at the picture :)

that wont work because the map is daimond shaped.

Not sure if this is the best in practice but I would do everything as if the map was square then just the rendering stage would convert that to dimond shape for the drawing part only.

Quote:

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Originally posted by Electroman
Not sure if this is the best in practice but I would do everything as if the map was square then just the rendering stage would convert that to dimond shape for the drawing part only.

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But then you have the problem we're having which is allowing the user to click a tile where it's drawn. :confused:

Also, isn't that what he's done??

But if thats what you've done isn't it a simple process of running an X,Y position though the same function but backwards. Then you use the X,Y position given out from that and use a simple grid to find out which square it lies on then?

*brambel brambel brambel*

woulndt work. and if it would please show me

Quote:

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Originally posted by Electroman
But if thats what you've done isn't it a simple process of running an X,Y position though the same function but backwards. Then you use the X,Y position given out from that and use a simple grid to find out which square it lies on then?

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That's what i've been puzzling over once i realized my previous suggestion, and shell's wouldn't work.

So I would say you would use this Function to get the Io position on your map (Where ZeroPos is the Origin on the iso view)

VB Code:

Private Type PointXY
    X As Integer
    Y As Integer
End Type
 
Private Function GetIsoPos(ByRef ZeroPos As PointXY, ByRef NormPos As PointXY) As PointXY
Dim Retn As PointXY
    
    Retn.X = ZeroPos.X + (NormPos.X / 2) + (NormPos.Y / 2)
    Retn.Y = ZeroPos.Y + (NormPos.Y / 2) - (NormPos.X / 2)
    
    GetIsoPos = Retn
End Function

Then all you need is a function to work this backwards?

what? i dont get it :|

do what backwords?

and how would that help

because the mouse position is gonna be in Iso and you want to know what it is in normal space. To Convert a point from Normal to Iso you would use the above function. For example:

If you put the position (TILE_WIDTH, TILE_HEIGHT) into the function it would point to here on your picture:
http://www.vbforums.com/attachment.p...postid=1793820

Assuming the Red circle marks the ZeroPosition,

i dont want to convert the mousecords to iso.
i want to determine what tile you click.

i dont really know what you mean

But once you have the Mouse position in Normal coords you can then use a very simple method to determine which tile the position is on.....

pff can you write an example project, i still dont get it

yea, just noticed your grid is based on 0,0 being the topmost position so the Function I posted above woill be a little different (chnage the minus sign to a plus ;))

Will make a example in a sec....

Quote:

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Originally posted by Electroman
yea, just noticed your grid is based on 0,0 being the topmost position so the Function I posted above woill be a little different (chnage the minus sign to a plus ;))

Will make a example in a sec....

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i apriciated your help alot :bigyello:
and thanks slh and merri too

Here you go, I've missed out the GetNormPos() Function but I'm still thinking of the best way to do it. The project demonstrates how to use the function above to convert a normal position to Iso then the mouse position back to Normal Position and then select the appropriate tile.

*** thats wierd. how can that help

Guess you need the GetNormPos() function completed before you'll understand :doh:

Humm, I've had a go at the function but theres a bit of a bug in it :(. I've attached it as it is and set to to plot the mouses position as you move it but you'll see as you move away from the origin there is an increasing error :(.

In this Picture you'll see I've ploted lots of positions within the PictureBox and the shape produced "should" have been the shape of the picturebox :(.
http://www.vbforums.com/attachment.p...postid=1793891

The Pic


BTW I'll explain the way i was trying to do it in a few minutes, just gotta go out to give someone a lift. Be Back Soon.....

i knew you ment it like that. thats not what i mean

Don't ask how but I did it, I'm currently trying to figure out why Retn.Y isn't d * Cos(Pi / 4).

VB Code:

Private Function GetNormPos(ByRef ZeroPos As PointXY, ByRef IsoPos As PointXY) As PointXY
Dim Retn As PointXY
Dim Xi As Integer
Dim d As Integer
 
    Xi = IsoPos.X - ZeroPos.X
    d = (IsoPos.Y - ZeroPos.Y) - Xi
    
    Retn.Y = d
    Retn.X = Retn.Y + (2 * Xi)
    
    GetNormPos = Retn
End Function

I have attached the original project and now it selects the tiles as you move over them. Is this not what you were after?

:eek2:

i was wong, ok i will go trough the code to try and understand it

thanks alot

ok i understand your code. but it wont work for me.... the 0,1 is calculated as 0.0 and 0.0 as 0,-1

VB Code:

Public Sub MouseToMap(ByVal MouseX As Long, ByVal MouseY As Long, ByRef MapX As Long, ByRef MapY As Long)
    Dim Z As Long
    Dim X As Long
    Dim Y As Long
    
    Let Z = Header.Width * TILE_WIDTH / 2
 
    Let X = MouseX - Z
    Let Y = MouseY - X
    Let X = Y + 2 * X
    
    Let MapX = CInt(X / TILE_WIDTH - 0.5)
    Let MapY = CInt(Y / TILE_BASE_HEIGHT - 0.5)
End Sub

1

Lets go with the math:

VB Code:

Private Sub Picture1_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single)
    Dim NewX As Long, NewY As Long
    Const XPadding As Long = 192
    NewX = (X - XPadding) \ 2
    NewY = Y - NewX 
    NewX = NewX + Y
    Caption = Int(NewX / 32) & " x " & Int(NewY / 32)
End Sub

XPadding changes depending on where is the middle pixel of the first block. There are four pixels in the top of first block. This value should point to the third of them.

What this does is that it converts the X and Y location into non-isometric format, like if it was a traditional 2D map. That's why I use 32 as tile width and height (this matches what you use as your tiles). Then it is simple to convert the X and Y locations to the according tile.

Hope it works :)


Edit Darn, there is a bug! Need to start figuring it out...
Edit #2 Phew, I just forgot to do one calculation :)

ugh?

Maybe within a project it explains it better.

how do i calc that position then?

You mean XPadding?

(TileWidth \ 2) * TotalNumberOfVerticalTiles

or

TotalFieldWidth \ 2



Please note that later on you must add to MouseX and MouseY the camera position your field is displayed from.

yeah i love you merri, thanks for helping me. i dont understand what \ is for thou...

It is basically the same as /, it just doesn't work with negative numbers and it can't count decimals. But it is two times faster than / (the more the bigger numbers you have).

What it does is that it counts how many times the second number you give fits in the first number.

5 \ 2 = 2
5 \ 3 = 1
7 \ 3 = 2
1 \ 2 = 0
2 \ 2 = 1

ok is using bla \ bla better then int(bla / bla)?

VB Code:

Public Sub MouseToMap(ByVal MouseX As Long, ByVal MouseY As Long, ByRef MapX As Long, ByRef MapY As Long)
    Dim Z As Long
    Dim X As Long
    Dim Y As Long
    
    Let Z = Header.Width * TILE_WIDTH \ 2 + TILE_WIDTH \ 2 - 1
 
    Let X = (CameraX + MouseX - Z) \ 2
    Let Y = CameraY + MouseY - X
    Let X = X + CameraY + MouseY
    
    Let MapX = X \ (TILE_WIDTH \ 2)
    Let MapY = Y \ (TILE_BASE_HEIGHT + 1)
End Sub

you told about the camera to the mousex/y right? when i add those it gets wrong; when i click 0,0 the 0,4 gets calced. i added tile_Width and tile_base_height to the camerax/y

without camera its works fine..

lol i have todo - instead of +

Well, a lot of depends on how your camera works: if position 0, 0 is like the previous screenshots, then it should work right. I don't know how your camera is utilized, so I can't give exact advice on it. Hmm... or I guess you meant with your last post that you had to invert the camera values. Can't be sure :)

Using X \ X is for the least faster than Int(X / X) - but note it still can't do negative numbers.

cool evrything works perfectly now :thumb:

I don't know if anyone cares, but I made an isometric engine aswell.
It does not use that template image method to calculate where the mouse is, but rather just simple old math rutines.

The game is in C, but i think you'll all get the picture =)

The game can be found here:

http://www.jonask.com/c/bygge.zip

But a simpler verson of the engine is deplyed here
http://www.jonask.com/c/isospill.zip

Both games requires allegro runtime libs:
http://www.jonask.com/c/drivere/alleg40.dll

what if the screen is not daimond shaped?

Quote:

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Originally Posted by nareth

what if the screen is not daimond shaped?

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Being Isometric means a square map will be diamond so it would still work....If the Non-Isometric of the map is not square then you would achive this by making a bigger square and removing tiles so thats all you do once its Isometric ;).