Matrix Transformations of Points / Vectors

[Ma-Shell]

Hi,

I noticed, Leadwerks has functions for transforming vectors and points to different spaces. However, I am not really sure, what to think of the following things:

 

I would have thought, transformation of the point A into the space of the matrix M simply means multiplying the matrix (from left) with setting the fourth coordinate of the point to 1:

A' = M*A

The same for vectors but just have the fourth coordinate be 0 instead of 1. I wrote the following code to do a matrix multiplication:

 

ret = Vec4(0)
for i = 0,3,1 do
ret[i] = 0
for j = 0,3,1 do
 ret[i] = ret[i] + M[i][j] * A[j]
end
end

 

(I also noticed, the matrix of self.entity:GetMatrix() has to be transposed before doing this because otherwise the last row is not 0,0,0,1, which is a MUST for transformation-matrices).

However,

Transform:Vector() and Transform:Point() all yield different results and I can't figure out, why.

Transform:Vector yields quite similar results to my function, if I do not transpose the matrix beforehand, except for the fourth coordinate. The values yielded by Transform:Point() don't seem to be related to my values at all. Consider the following example code:

 

local M = self.entity:GetMatrix():Transpose()
local A = Vec4(0,0,1,0)
System:Print(mat)
ret = Vec4(0)
for i = 0,3,1 do
ret[i] = 0
for j = 0,3,1 do
 ret[i] = ret[i] + M[i][j] * A[j]
end
end

local a = Vec3(0,0,1)
local v = Transform:Vector(a, nil, self.entity)
System:Print(v[0] .. "," .. v[1] .. "," .. v[2] .. "," .. v[3])
local v = Transform:Point(a, nil, self.entity)
System:Print(v[0] .. "," .. v[1] .. "," .. v[2] .. "," .. v[3])
System:Print(ret[0] .. "," .. ret1] .. "," .. ret[2] .. "," .. ret[3])

 

All of these yield different values, when actually Transform:Vector should be the same. If I change the last coordinate of A to 1 instead of 0, Transform:Point should be the same. Can anyone enlighten me on this?