How to check in LUA in what direction a river flows?

[LDeska]

I created a map script that reflects half of map. It works fine - terrain, featuers, natural wonders, starting positions, rivers - everything is mirrored but I can't get rid of very annoying thing - the river flows in incorrect directions. The reason is that nowhere in LUA files I haven't spotted a function that reads river direction. There is a check if a plot is next to a river:
plot:IsWOfRiver()
plot:IsNWOfRiver()
plot:IsNEOfRiver()
and there are functions to set it but it requires second parameter - directions which I'm unable to read from the original plot:
mirror_plot:SetWOfRiver(true,FlowDirectionTypes.NO_FLOWDIRECTION)
mirror_plot:SetNWOfRiver(true,FlowDirectionTypes.NO_FLOWDIRECTION)
mirror_plot:SetNEOfRiver(true,FlowDirectionTypes.NO_FLOWDIRECTION)

So, do I have to wait till Firaxis will finally release such info or I can somehow get this info from Civ5 files?

 

[Nercury]

Can you somehow rebuild those rivers, based on where they end? I know, that may be too much work, and I haven't looked into it yet.

 

[LDeska]

I'm not convinced that it will be easy to determine where river ends. For now I think that easiest workaround is to remove all the rivers, copy the part of code that creates the rivers (they use recurrency for this :-O ) and modify it to put rivers on both parts of map - "source" and mirrored half... But it's ridiculous

 

[Nercury]

I'm not convinced that it will be easy to determine where river ends. For now I think that easiest workaround is to remove all the rivers, copy the part of code that creates the rivers (they use recurrency for this :-O ) and modify it to put rivers on both parts of map - "source" and mirrored half... But it's ridiculous

Oh well, I guess it is still better than rivers uphill

 

[EmperorFool]

GetRiverDirection() probably won't fly because a plot can be multiple rivers. What about GetWRiverDirection() or GetRiverDirectionW()? Is there no way to inspect the objects in Lua as there is in Python? I haven't had a chance to dive in yet, but I believe you can output all of the valid indexes (methods) in a table (object) in Lua.

Here's a stab at it. Try this once you have code that access a Plot object.

plot = ...
for i, v in ipairs(plot) do
    print(i)
end

Edit: Bah, ipairs() strictly works with integer indexes. There must be a function that will return all of the named indexes.

 

[Nercury]

Edit: Bah, ipairs() strictly works with integer indexes. There must be a function that will return all of the named indexes.

pairs probably

 

[EmperorFool]

That's the trouble with not playing with the language yet.

 

[LDiCesare]

Yes, pairs returns all the indexes, ints and others.
ipairs returns the first consecutive integer indices, starting at one.
so for a table with elements at 0,1,2,3,5 as keys, ipairs will return the values for 1,2,3.

 

[EmperorFool]

Ah, so ipairs() always starts at 1? I understand that tables normally start with 1 instead of 0 if you allow the indexes to be assigned automatically. And I did read that it stops with the highest consecutive index. Good to know it skips any indexes below 1, too.

 

[LDeska]

Eh.. I played yesterday all evening so I haven't checked it and here at work I use Linux so I'm not able to test if I can print out method names. But from your posts I understand that this pairs/ipairs will not print out method names of Plot object?

 

[LDiCesare]

pairs can print method names.
For instance
table t =
{
method1 = function( self ) rreturn 42 end,
aValue = 44
}
for i,j in pairs(t) do print i end
Will print
method1 and aValue.
One safety trick if you want to print stuff: Concatenation si done with .. operator but it doesn't like to concatenate non string objects so make sure you use ..tostring( stuff ) when you concatenate strings in case stuff is an integer for instance.

 

[LDeska]

Hmm interesting, I have to test it when I'll get back home, do you think that it will work?

plot = ...;
for i,j in pairs(plot) do
print i;
print j;
end;

How to check of what type is variable "j" ? It would be ideally if I could check somehow what are the parameters that I need to pass to this method. Maybe LUA supports reflection like in Java ?

But honestly, Firaxis haven't done good job - they released Civ5 way too early. They should release SDK-LUA interface together with game!

 

[Nercury]

How to check of what type is variable "j" ? It would be ideally if I could check somehow what are the parameters that I need to pass to this method. Maybe LUA supports reflection like in Java ?!

type(j)

here: http://sourceforge.net/apps/mediawiki/civ4bug/index.php?title=Lua:_Types_and_Values

 

[EmperorFool]

There's no need to print the second value from pairs(). You just need the names (indexes) in the table. For the most part we should be able to tell what the thing is by its name, but further I expect that the objects hold only methods as they did in the Python SDK. To get the name field of a CyCity you would call CyCity.getName() which went into C++ and returned the value in the field.

BTW, this is reflection as far as Lua is concerned. Lua has only tables and primitive values. There is no such thing as classes and objects in Lua--they are all tables. Object methods are merely a convention of storing functions in metatables.

 

[Nercury]

I am just using it like javascipt, my class looks like this:

ClassName = function() -- << this serves as constructor too

    local b = function() -- << private function
        return 0
    end

    local self = {
        a = function() -- << public function
            return b()
        end, 
    }

    return self;
end

local instance = ClassName()

This works quite well. Is it ok to do this in lua? Never found any example like this, so I am a bit wary.

EDIT: sorry for derailing thread completely, I have just realized that...

 

[LDeska]

I have error when trying to run loop like

for i,j in pairs(plot) do
...
end

I have syntax error saying:

[1454.615] Syntax Error: [string "Assets\Maps\LD_Mirror_Pangaea.lua"]:508: '=' expected near 'i'

it looks like it's not possible to put two variables after "for", it expects equal sign after first variable. I tried to put it inside parenthesis like for (i,j) in .. but it also didn't worked. It failed on first parenthesis.

 

[Nercury]

Line

for offset, _ in pairs(tilesOffset) do

Works fine for me. Maybe you forgot an "end" or "then" and compiler is just confused? Start by commenting-out portions of your code

 

[LDeska]

I made it work by using this underscore but it haven't helped me at all....

	local plot1 = Map.GetPlot(1, 1)
	print "LD start"
	--print plot1
	local offset;
	for offset, _ in pairs(plot1) do
		print(offset)
	end
	print "LD stop"

produced:

[8520.369] Map Script: Map Generation - Normalize City State Locations
[8520.369] Map Script: LD start
[8520.369] Map Script: __instance
[8520.369] Map Script: LD stop
[8520.369] Map Script: -------------------------------
[8520.369] Map Script: Map Generation - Adding Goodies

so in fact it iterated only once, the key is equal "__instance"

 

[LDiCesare]

Why should the plot have data in the first place? It's probably a pointer to a C++ object.
What are you trying to retrieve? The rivers adjacent to a plot? It's probably doable only through function calls, not iterations.

 

[LDeska]

I want to read direction of river - I know it's doable via function calls but I don't know how those functions are named. EmperorFool proposed to read function names using such loop - but it doesn't work.
I'm really angry over Firaxis for not releasing that SDK-LUA interface... I'll keep trying and will notify you with my results