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o3de/Assets/Engine/Scripts/Utils/Math.lua

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Lua

----------------------------------------------------------------------------------------------------
--
-- Copyright (c) Contributors to the Open 3D Engine Project.
-- For complete copyright and license terms please see the LICENSE at the root of this distribution.
--
-- SPDX-License-Identifier: Apache-2.0 OR MIT
--
--
--
----------------------------------------------------------------------------------------------------
function ConstVec(v)
return v
end
----------------------------------------------------
-- global Vectors table and some vector functions
----------------------------------------------------
g_Vectors =
{
v000=ConstVec({x=0,y=0,z=0}),
v001=ConstVec({x=0,y=0,z=1}),
v010=ConstVec({x=0,y=1,z=0}),
v011=ConstVec({x=0,y=1,z=1}),
v100=ConstVec({x=1,y=0,z=0}),
v101=ConstVec({x=1,y=0,z=1}),
v110=ConstVec({x=1,y=1,z=0}),
v111=ConstVec({x=1,y=1,z=1}),
up = ConstVec({x=0,y=0,z=1}),
down = ConstVec({x=0,y=0,z=-1}),
temp={x=0,y=0,z=0},
tempColor={x=0,y=0,z=0},
temp_v1={x=0,y=0,z=0},
temp_v2={x=0,y=0,z=0},
temp_v3={x=0,y=0,z=0},
temp_v4={x=0,y=0,z=0},
temp_v5={x=0,y=0,z=0},
temp_v6={x=0,y=0,z=0},
vecMathTemp1={x=0,y=0,z=0},
vecMathTemp2={x=0,y=0,z=0},
}
-----------------------------------------------------------------------------
-- Math constants
-----------------------------------------------------------------------------
g_Rad2Deg = 180/math.pi;
g_Deg2Rad = math.pi/180;
g_Pi = math.pi;
g_2Pi = 2*math.pi;
g_Pi2 = 0.5*math.pi;
-----------------------------------------------------------------------------
-- Import commonly used math functions from math. table to global namespace.
-----------------------------------------------------------------------------
random = math.random;
math.randomseed(os.time()); -- seed and pop
random();
-----------------------------------------------------------------------------
function IsNullVector(a)
return (a.x==0 and a.y==0 and a.z ==0);
end
function IsNotNullVector(a)
return (a.x~=0 or a.y~=0 or a.z ~=0);
end
function LengthSqVector(a)
return (a.x * a.x + a.y * a.y + a.z * a.z);
end
function LengthVector(a)
return math.sqrt(LengthSqVector(a));
end
function DistanceSqVectors(a, b)
local x = a.x-b.x;
local y = a.y-b.y;
local z = a.z-b.z;
return x*x + y*y + z*z;
end
function DistanceSqVectors2d(a, b)
local x = a.x-b.x;
local y = a.y-b.y;
return x*x + y*y;
end
function DistanceVectors(a, b)
local x = a.x-b.x;
local y = a.y-b.y;
local z = a.z-b.z;
return math.sqrt(x*x + y*y + z*z);
end
-----------------------------------------------------------------------------
function dotproduct3d(a,b)
return (a.x * b.x) + (a.y * b.y) + (a.z * b.z);
end
-----------------------------------------------------------------------------
function dotproduct2d(a,b)
return (a.x * b.x) + (a.y * b.y);
end
function LogVec(name,v)
Log("%s = (%f %f %f)",name,v.x,v.y,v.z);
end
function ZeroVector(dest)
dest.x=0;
dest.y=0;
dest.z=0;
end
function CopyVector(dest,src)
dest.x=src.x;
dest.y=src.y;
dest.z=src.z;
end
----------------------------------
function SumVectors(a,b)
return {x=a.x+b.x,y=a.y+b.y,z=a.z+b.z};
end
function NegVector(a)
a.x = -a.x;
a.y = -a.y;
a.z = -a.z;
end
----------------------------------
function SubVectors(dest,a,b)
dest.x = a.x - b.x;
dest.y = a.y - b.y;
dest.z = a.z - b.z;
end
----------------------------------
function FastSumVectors(dest,a,b)
dest.x=a.x+b.x;
dest.y=a.y+b.y;
dest.z=a.z+b.z;
end
----------------------------------
function DifferenceVectors(a,b)
return {x=a.x-b.x,y=a.y-b.y,z=a.z-b.z};
end
----------------------------------
function FastDifferenceVectors(dest,a,b)
dest.x=a.x-b.x;
dest.y=a.y-b.y;
dest.z=a.z-b.z;
end
----------------------------------
function ProductVectors(a,b)
return {x=a.x*b.x,y=a.y*b.y,z=a.z*b.z};
end
----------------------------------
function FastProductVectors(dest,a,b)
dest.x=a.x*b.x;
dest.y=a.y*b.y;
dest.z=a.z*b.z;
end
----------------------------------
function ScaleVector(a,b)
return {x=a.x*b,y=a.y*b,z=a.z*b};
end
function ScaleVectorInPlace(a,b)
a.x=a.x*b;
a.y=a.y*b;
a.z=a.z*b;
end
----------------------------------
function NormalizeVector(a)
local len=math.sqrt(LengthSqVector(a));
local multiplier;
if(len>0)then
multiplier=1/len;
else
multiplier=0.0001;
end
a.x=a.x*multiplier;
a.y=a.y*multiplier;
a.z=a.z*multiplier;
return a
end
----------------------------------
function FastScaleVector(dest,a,b)
dest.x=a.x*b;
dest.y=a.y*b;
dest.z=a.z*b;
end
--linear interpolation
----------------------------------
function LerpColors(a,b,k)
g_Vectors.tempColor.x = a.x+(b.x-a.x)*k
g_Vectors.tempColor.y = a.y+(b.y-a.y)*k
g_Vectors.tempColor.z = a.z+(b.z-a.z)*k
return g_Vectors.tempColor;
end
----------------------------------
function Lerp(a,b,k)
return (a + (b - a)*k);
end
----------------------------------
function __max(a, b)
if (a > b) then
return a;
else
return b;
end
end
----------------------------------
function __min(a, b)
if (a < b) then
return a;
else
return b;
end
end
----------------------------------
function clamp(_n, _min, _max)
if (_n > _max) then _n = _max; end
if (_n < _min) then _n = _min; end
return _n;
end
----------------------------------
function Interpolate(actual,goal,speed)
local delta = goal - actual;
if (math.abs(delta)<0.001) then
return goal;
end
local res = actual + delta * __min(speed,1.0);
return res;
end
-----------------------------------
function sgn(a)
if (a == 0) then
return 0;
elseif (a > 0) then
return 1;
else
return -1;
end
end
-----------------------------------
function sgnnz(a)
return (a>=0) and 1 or -1;
end
-----------------------------------
function sqr(a)
return a*a;
end
-----------------
function randomF(a,b)
if (a>b) then
local c = b;
b = a;
a = c;
end
local delta = b-a;
return (a + math.random()*delta);
end
function VecRotate90_Z(v)
local x = v.x;
v.x = v.y;
v.y = -x;
end
function VecRotateMinus90_Z(v)
local x = v.x;
v.x = -v.y;
v.y = x;
end
function iff(c,a,b)
if c then return a else return b end
end
-----------------------------------------------------------------------------
-- calculate cross product
function crossproduct3d( dest, p, q )
dest.x = p.y*q.z-p.z*q.y;
dest.y = p.z*q.x-p.x*q.z;
dest.z = p.x*q.y-p.y*q.x;
end
-- rotate vector p around vector r by angle
-- the length of r needs to be 1
function RotateVectorAroundR( dest, p, r, angle )
-- p' = v1 + v2 +v3
-- v1 = pcosA
-- v2 = r**psinA;
-- v3 = r< r,p >( 1- cosA );
local cosValue = math.cos( angle );
local sinValue = math.sin( angle );
local v1 = {};
local v2 = {};
local v3 = {};
local vTmp = {};
-- v1
CopyVector( v1, p );
FastScaleVector( v1, v1, cosValue );
-- v2
CopyVector( vTmp, p );
FastScaleVector( vTmp, vTmp, sinValue );
crossproduct3d( v2, r, vTmp );
-- v3
CopyVector( v3, r );
FastScaleVector( v3, v3, dotproduct3d( r, p ) );
FastScaleVector( v3, v3, 1.0 - cosValue );
-- p'
CopyVector( dest, v1 );
FastSumVectors( dest, v1, v2 );
FastSumVectors( dest, dest, v3 );
end
-- project P to the surface whose normal vector is N.
function ProjectVector( dest, P, N )
-- projected vector is vector X (output)
-- X =P+(-P*N)N
local minusP ={};
FastScaleVector( minusP , P , -1.0 );
local t = dotproduct3d( minusP, N );
CopyVector( dest , N );
FastScaleVector( dest , dest , t );
FastSumVectors( dest , dest , P );
end
-- get a distance between line(pt+q) and point(a)
function DistanceLineAndPoint( a, p, q )
-- d=|| p * (a-q) || / ||p||
local length = LengthVector( p );
local outerProduct;
local vOuterProduct = {};
local vTmp = {};
local d;
SubVectors( vTmp, a, q );
crossproduct3d( vOuterProduct, p, vTmp );
outerProduct =LengthVector( vOuterProduct );
if ( length>0.01 ) then
d = outerProduct/length;
else
d = 0.0;
end
return d;
end
-- Get normalized direction vector from point 'a' to point 'b'
function GetDirection(a, b)
local dir = {};
SubVectors(dir, b, a);
NormalizeVector(dir);
return dir;
end
function GetAngleBetweenVectors2D(a, b)
return math.acos(dotproduct2d(a, b));
end
function GetAngleBetweenVectors(a, b)
return math.acos(clamp(dotproduct3d(a, b), -1, 1));
end