Bone translation, scaling, and rotation in Lua

Deco · February 2014

Hello,

I would greatly appreciate it if a Spark engine developer added the following method:

CoordsArray:Set(boneNum, coords)

Example usage:

function Player:GetForbidModelCoordsUpdate()
    local renderModel = self._renderModel
    if renderModel ~= nil then
        local boneCoords = self.boneCoords
        for i = 0, boneCoords:GetSize()-1 do
            local coords = boneCoords:Get(i)
            coords.yAxis = coords.yAxis*math.random() -- Randomly scale each bone vertically
            boneCoords:Set(i, coords)
        end
        RenderModel.SetBoneCoords(renderModel, boneCoords)
        RenderModel.SetCoords(renderModel, self._modelCoords)
        RenderModel.SetIsVisible(renderModel, self:GetIsVisible())
    end
    return true
end

This would allow Lua modders to programmatically "rearrange" models without the need to make new models and animation graphs.

An example application is moving the fingers of an exo, such as Scatter requires for his exo-shield (the fingers will fold back and emit blue light).

Another application is model-splicing. Setting the scale of a bone to zero and attaching another render model in its place allows modders to mix-and-match models. This would make a dual-claw exo possible without needing to create a new model and animation graph.
It would also allow for hiding the exo's fist for a rocket-fist mod.

An alternative to adding CoordsArray:Set, is to inform us of the FFI C-definition of the CoordsArray struct. That way we can do this:

local coords1 = Coords.GetIdentity()
local coords2 = Coords.GetIdentity()
local coordsArray = ffi.new("CoordsArray", { someVariableName = { coords1, coords2, ... } })
...

Where "someVariableName" is the field name we need to know to initialise a CoordsArray.

Please consider this request,
Thank you,
Declan W.

P.S: Model transformation and splicing is used very frequently in Garry's Mod, namely in the Player Appearance Customizer addon. There is little, if any, affect on performance.

IronHorse · February 2014

Forwarding this to the devs, thanks!

Deco · March 2014

Looks like this didn't get to the devs... thanks anyway, IronHorse

Does anyone know how to get their attention? This is an extremely easy method to add and would open up many modding avenues.

In NS2.exe already:

function CoordsArray:GetSize()
    return (pkg.CoordsArray_GetSize(self))
end

function CoordsArray:Get(i)
    local __cdataOut = Coords()
    pkg.CoordsArray_Get(self, i, __cdataOut)

    return __cdataOut
end

To add:

function CoordsArray:Set(i, coords)
    pkg.CoordsArray_Set(self, i, coords)
end

Along with the C++ definition for:

void CoordsArray_Set(CoordsArray& self, int i, const Coords& coords);

JimWest · March 2014

Mhm whats the difference from the thing you want to the function

 "name": "SetBoneCoords",
                    "arguments": [
                        {
                            "type": "CoordsArray",
                            "name": "boneCoords"
                        }
                    ]

Deco · March 2014

You can use that to set the bone coords of a RenderModel to the values in a CoordsArray.
But, you can only set the values of that CoordsArray from the "poses" of the RenderModel or the positions of the bones in the PhysicsModel.
There's no way to set individual bone values.

(that is, CoordsArray is "const" on the Lua side, and can only be set by the engine, due to the lack of CoordsArray:Set(boneNum, coords) .)

If there was, it would be possible to scale the marine's head to zero, and put a skulk's head there.
Or rotate the fingers of an exo.
Or scale the size of a lerk's wings.
etc, etc..

Deco · November 2014

@IronHorse: Did the devs ever get around to this?

SamusDroid · November 2014

I forwarded this to people who can do something about this on the CDT

Deco · November 2014

Thanks!

I look forward to playing with it

IronHorse · November 2014

Ya development was in a weird place back then, everything was in flux / limbo. But now the CDT is at the helm and is quite effective

Thanks for bringing this back up!

matso · November 2014

https://trello.com/c/UQCzRnF0

Nordic · November 2014

I am interested to see how people might end up using this.

matso · December 2014

You could use it for a simplified inverse-kinematics driven animation of legs : change the leg joints to move the feet so they touch the ground the skulk is clinging on ... the current animation driven one just assume the skulk is hanging on a flat surface. Looks really silly in the wrong place.

Soul_Rider · December 2014

You could also make really simple mutations etc for zombies, or deform/transform the bones of current models to make them look differntly basic on changes in the game etc. Basically, the possibilities are endless, though for me this all comes a little late in the day.

Though I really appreciate the work the CDT is doing for NS2, the constant development of the engine and game means large scale mods, particularly full-game mods, still get broken like clockwork with a patch. This might not be such a problem for bigger teams, but for a single modder, having to fix your mod for updates all the time eventually breaks your will to develop for the engine anymore.

While I think it is great this is being added, we really needed it when it was being asked for

Scatter · January 2015

Is this still being included in 273 ?

GhoulofGSG9 · January 2015

Scatter wrote: »

Is this still being included in 273 ?

Have a look at the trello board it's hanging in approved( 274 )

So atm we sadly didn't had time to look at it. There is just so much stuff to do and so less time and devs.

Bone translation, scaling, and rotation in Lua

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