Iso Engine Mouse Coordinates -[RESOLVED]-

[CodeRonin]

Hi there,
by now, I've finished the graphical display of my Iso Engine.

I'm saving the Tiles in a 2dimensional Matrix, so my GameField looks like this...

GameTile GTMAP[10][10] =
{
1,1,1,4,1,1,1,1,1,1,
1,1,1,1,1,1,1,1,1,1,
1,1,1,1,1,1,1,1,1,1,
1,1,2,3,4,1,1,1,1,1,
1,1,1,2,3,1,1,1,1,1,
1,1,2,1,6,1,1,1,1,1,
1,1,1,1,1,1,1,1,1,1,
1,1,1,1,1,1,1,1,1,1,
1,1,1,1,1,1,1,1,1,1,
1,1,1,1,1,1,1,1,1,1,
}

Where every number stands for a different type of terrain (not hardcoded, of course).

Now, my question is: Given a paoint X(x/y) on the map (a mouse coordinate, to be precise), how can I check which tile I am in?

Since it's not standard rectacular, a normal division by height and width won't work, so my attempt was to first do the normal division to know where about i am, seperate the most likely tile into four triangles, use the formula y=kx+d for linear functions and get the max for my y coordinate this way...

Unfortunately, that's too slow...
Any ideas on how to do it?

[SLH]

If you know the height and width of a tile wouldn't it be something like this??

TileX = int(MousePosX/TileWidth)
TileY = int(MousePosY/TileHeight)

Or is that not quite what you want?

[nareth]

noteme he sayd NOT a rectangular so that is wrong.. lemme find a tutorial for you.

[NoteMe]

Originally posted by nareth
noteme he sayd NOT a rectangular so that is wrong.. lemme find a tutorial for you.

That was not NoteMe.......SLH has hijacked my avatar..

[nareth]

gr my matrix is overloaded. sorry

[SLH]

Originally posted by nareth
noteme he sayd NOT a rectangular so that is wrong.. lemme find a tutorial for you.

Well if it's not recrangular (implied by the array) then how are we to know what would be correct (considering that we don't know the actual shape)??

[SLH]

Originally posted by NoteMe
That was not NoteMe.......SLH has hijacked my avatar..

Mwhahahaha!!

[nareth]

isometric he mentioned it in the title

[SLH]

Originally posted by nareth
isometric he mentioned it in the title

Ah.

Surely he can just pretty much use the code he's already got to display the matrix on the screen, just 'reverse' the formula...

[nareth]

http://www.gamedev.net/reference/art...article747.asp

[kedaman]

To convert between rectangular and isometric coordinates you just need to do a matrix transformation, you multiply the coordinate with a matrix of which columns are the vectors of how many times each step on rectangular will translate to isometric

[nareth]

First Step: Find out what region of the map the mouse is in.

RegionX=int(MouseX/MouseMapWidth)
RegionY=int(MouseY/MouseMapHeight)*2 {The multiplying by two is very important}

Second Step: Find out WHERE in the mousemap our mouse is, by finding MouseMapX and MouseMapY.

MouseMapX=MouseX MOD MouseMapWidth
MouseMapY=MouseY MOD MouseMapHeight


Third Step: Determine the color in the MouseMap at (MouseMapX,MouseMapY).


Fourth Step: Find RegionDX and RegionDY in the following table:

Color RegionDX RegionDY
RED -1 -1
YELLOW 0 -1
WHITE 0 0
GREEN -1 1
BLUE 0
1



Fifth Step: Use RegionX,RegionY, RegionDX, and RegionDY to find out TileX and TileY

TileX=RegionX+RegionDX
TileY=RegionY+RegionDY

[CodeRonin]

That tutorial helped, thank you very much.
I really appreciate it.

[kedaman]

hahaha @SLH, nice puppet bashing

here's the basic idea behind isometric projection, you multiply the vector from right with a transformation matrix with the rectangular coordinates to get the isometric coordinates.

[SLH]

Originally posted by kedaman
hahaha @SLH, nice puppet bashing

Credit where credit's due. It was Electroman that did the avatar.

[Electroman]

Posted by SLH
Credit where credit's due. It was Electroman that did the avatar.

[kedaman]

Nice one Electroman btw whats that av in yours suppose to be doing

[CodeRonin]

What is the MouseMap?

[Electroman]

Posted by kedaman
Nice one Electroman btw whats that av in yours suppose to be doing

Opps I missed the second half of your post some how......Its SLH's old avatar (the one with the smilie jumping out the toilet) but I turned it upside down and added water falling out the toilet .