[Misc] Tile length, its coordinates and center

[Wrda]

Why is this relevant?
One day I figured I needed a way to know the center of a tile, given an axis coordinate. Such thing isn't available to us directly so I did it myself. Also this is important for our common knowledge that sometimes we take for granted.

Assumptions
Our intuition would say that the length of a tile is exactly 128.00, and that given the tile of the center of the map, which is at 0, 0, would have the edges as 64.00, 64.00, -64.00, -64.00 (up, right, down, left edges respectively).
Upon having a loop to check each edge, this assumption was just wrong. Edges are 63.499, 63.499, -64.500, -64.500 (same order as above), length is 127.999 instead.

Researched method
I delved into a basic method to find out the edges of a tile by alternating between 2 different tile types, and with a loop, which increases an axis point (variable r in test map).

Figuring out the logic
My first attempt was pretty wack, quite inacurate, still useful in certain situations. The second is fully accurate, although it appears to be somewhat slower? Not very significative I hope.

Spoiler: First attempt

function GetTileCenter takes real x returns real
    local real abs = RAbsBJ(x)
    local real mod = ModuloReal(abs, 128.00)
    local real multiples = R2I(abs/128)
    if mod >= 63.500 and x > 0 then
        return (128*(multiples + 1))*RSignBJ(x)
    elseif mod >= 64.501 and x < 0 then
        return (128*(multiples + 1))*RSignBJ(x)
    elseif mod == 0 and multiples >= 1 then
        return (128*(multiples))*RSignBJ(x)
    endif
    return (abs - mod)*RSignBJ(x)
endfunction

Spoiler: Accurate function

function GetTileCenterEx takes real x returns real
    local real result = RAbsBJ(x)
    if x < 0 then
        return (result - ModuloReal(result, 128.00))*-1
    endif
    return result - ModuloReal(result, 128.00)
endfunction

For lua:

Spoiler: Lua version of both functions

--INACCURATE
---@param x number
---@return number
function GetTileCenterEx(x)
    local result = math.abs(x)
    if x < 0 then
        return (result - math.fmod(result, 128.00))*-1
    end
    return result - math.fmod(result, 128.00)
end

--FULLY ACCURATE
---@param x number
---@return number
function GetTileCenter(x)
    local abs = math.abs(x)
    local mod = math.fmod(abs, 128.00)
    local multiples = math.floor(abs/128)
    local sign = 1
    if x < 0 then
        sign = -1
    end
    if mod >= 63.500 and x > 0 then
        return (128*(multiples + 1))*sign
    elseif mod >= 64.501 and x < 0 then
        return (128*(multiples + 1))*sign
    elseif mod == 0 and multiples >= 1 then
        return (128*(multiples))*sign
    end
    return (abs - mod)*sign
end

You can test it on the test map, just to see that I'm not going crazy..., yet.

 

[IcemanBo]

[vJASS] - [Snippet] TileDefinition

Info A specific terrain tile is defined by it's terrain type, but also through coordinates. While there exists a native GetTerrainType(), there is no native to get the geographical data of it. TileDefinition can give these geographical information about the location of a terrain tile. It can...

www.hiveworkshop.com

^ function GetTileCenterCoordinate is supposed to do the same.
Yeh, you're right with length. Edge coordinate precisely is the minimum x/y of one tile, but actually wouldn't belong as maximum of prior tile.

 

[Wrda]

I had seen this snippet before, but didn't really paid full attention to it
It does work nicely, with a margin of error of 0.501 on max edge, and 0.5 on min edge. Not sure it if it is a big deal.
Anyway, I still think this should be useful for people to be aware how annoying blizzard can be about these details.

 

[Chaosy]

I am hesitant to approve this as it's not really a tutorial but rather a "useful tip"
Also either I am blind or the first function and the accurate function are identical.

 

[Wrda]

I am hesitant to approve this as it's not really a tutorial but rather a "useful tip"

Yes, definetely not a tutorial, but I didn't find any other appropriate place to post this useful tip or a slight knowledge about something.

Also either I am blind or the first function and the accurate function are identical.

They were, because I'm stupid fixed.