Angular offset problem

[ralle105]

I'm really stuck on this one.

How can I get Angle(p, y, r) to be Angle(0, 0, 0) by only using Angle:RotateAroundAxis() and only rotating around it's own axises?

[highlight](User was banned for this post ("This isn't what spoiler tags are for" - mahalis))[/highlight]

[Dlaor]

I'm not sure, but you could maybe use [url=http://wiki.garrysmod.com/?title=Math.AngleDifference]Math.AngleDifference[/url]?

[ralle105]

[QUOTE=Dlaor;17120718]I'm not sure, but you could maybe use [url=http://wiki.garrysmod.com/?title=Math.AngleDifference]Math.AngleDifference[/url]?[/QUOTE]

That's not what I'm after, but thanks for trying :)

[Overv]

What does math.AngleDifference even do? Is it just something like this?

[lua]return math.abs( a % 360 - b % 360 )[/lua]

[Dlaor]

[QUOTE=Overv;17120854]What does math.AngleDifference even do? Is it just something like this?

[lua]return math.abs( a % 360 - b % 360 )[/lua][/QUOTE]
Something like that yeah, so that it doesn't return 359 when you calculate the difference between 359° and 0°

[Nev]

If you're working with entities, use LocalToWorldAngles and WorldToLocalAngles.

[Robert64]

Maybe try something like this using RotateAroundAxis:

[lua]local ang = otherEnt:GetAngles()
local offset = Angle( -p, -y, -r )

local fw = ang:Forward()
local up = ang:Up()
local rt = ang:Right()

ang:RotateAroundAxis( fw, p )
ang:RotateAroundAxis( up, y )
ang:RotateAroundAxis( rt, r )

thisEnt:SetAngles( ang )[/lua]

Although this may be wrong and it isn't tested.

[ralle105]

[QUOTE=Nevec;17120957]If you're working with entities, use LocalToWorldAngles and WorldToLocalAngles.[/QUOTE]

Im working with PhysObj's.

[Nev]

[QUOTE=ralle105;17120984]Im working with PhysObj's.[/QUOTE]

Damn garry.

Robert's code is the answer, except he got the axises wrong.

[lua]
local angParent = ent_parent:GetAngles( );
local vecPos = ent_parent:GetPos( );

vecPos = vecPos + angParent:Forward( ) * vecDiff.y;
vecPos = vecPos + angParent:Right( ) * vecDiff.x;
vecPos = vecPos + angParent:Up( ) * vecDiff.z;

ent_child:SetPos( vecPos );

angParent:RotateAroundAxis( angParent:Right( ), angDiff.p );
angParent:RotateAroundAxis( angParent:Up( ), angDiff.y );
angParent:RotateAroundAxis( angParent:Forward( ), angDiff.r );

ent_child:SetAngles( angParent );
[/lua]

Tested and works perfectly.

[ralle105]

[QUOTE=Nevec;17121144]Damn garry.

Robert's code is the answer, except he got the axises wrong.

[lua]
local angParent = ent_parent:GetAngles( );
local vecPos = ent_parent:GetPos( );

vecPos = vecPos + angParent:Forward( ) * vecDiff.y;
vecPos = vecPos + angParent:Right( ) * vecDiff.x;
vecPos = vecPos + angParent:Up( ) * vecDiff.z;

ent_child:SetPos( vecPos );

angParent:RotateAroundAxis( angParent:Right( ), angDiff.p );
angParent:RotateAroundAxis( angParent:Up( ), angDiff.y );
angParent:RotateAroundAxis( angParent:Forward( ), angDiff.r );

ent_child:SetAngles( angParent );
[/lua]

Tested and works perfectly.[/QUOTE]

Tested, and does not work perfectly. If you take an angle and rotate it around it's own axises with it's negated p,y,r values, it doesn't become 0,0,0.

[_Kilburn]

[QUOTE=ralle105;17121707]Tested, and does not work perfectly. If you take an angle and rotate it around it's own axises with it's negated p,y,r values, it doesn't become 0,0,0.[/QUOTE]

That's where we really need matrices and matrix inversions. [url]http://en.wikipedia.org/wiki/Change_of_basis[/url]