Isometric Engine Problem

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:

---

Originally Posted by nareth

what if the screen is not daimond shaped?

---

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 ;).

what he ment was
"what if the shape of the map is rectangular"

note hes banned .. im his friend(you can hceck ip if you want =)

Yea I know he is banned ;).

Anyway if its rectangular then it will still work, well the code I gave will at least not looked at the other code that got posted.

im posting for nareth know;

he says that his drawing function is messed

Code:

---

    Let xTemp = Map.Width * TileHalfWidth
    For X = 0 To Map.Width
        Let xDest = xTemp
        Let yDest = yTemp
       
        For Y = 0 To Map.Height
            Let rSrc.Left = Map.TileX(X, Y) * TileWidth
            Let rSrc.Top = Map.TileX(X, Y) * TileHeight
            Let rSrc.Right = rSrc.Left + TileWidth
            Let rSrc.Bottom = rSrc.Top + TileHeight
           
            Call BufferSurface.BltFast(xDest, yDest, GroundTiles, rSrc, DDBLTFAST_DONOTWAIT Or DDBLTFAST_SRCCOLORKEY)
           
            Let xDest = xDest + TileHalfHeight
            Let yDest = yDest + TileHalfWidth
        Next
       
        Let xTemp = xTemp - TileHalfHeight
        Let yTemp = yTemp + TileHalfWidth
    Next

---

and he send me this picture thru msn:

ahahahahaha i looked at the code. and im not good in directx but

Let xTemp = xTemp - TileHalfHeight
Let yTemp = yTemp + TileHalfWidth

even i noticed his mistake

he was so embarresed