nicklockwood/vectormath

A Swift library for Mac and iOS that implements common 2D and 3D vector and matrix functions, useful for games or vector-based graphics

vectormath's Issues

Initialize Quaternion from identity Matrix4 yields nan values

(lldb) po Quaternion(rotationMatrix: Matrix4.identity)
▿ Quaternion
  - x : nan
  - y : nan
  - z : 0.0
  - w : nan

Matrix3 / 4 multiplier order

Correct me if I'm wrong or midunderstangind something, but I think the order of matrix multiplication of VectorMath library seems reversed.

    public static func *(lhs: Matrix3, rhs: Matrix3) -> Matrix3 {
        
        return Matrix3(
            lhs.m11 * rhs.m11 + lhs.m21 * rhs.m12 + lhs.m31 * rhs.m13,
            .....
    }

    public static func *(lhs: Matrix4, rhs: Matrix4) -> Matrix4 {
        
        var m = Matrix4.identity
        
        m.m11 = lhs.m11 * rhs.m11 + lhs.m21 * rhs.m12
        m.m11 += lhs.m31 * rhs.m13 + lhs.m41 * rhs.m14
       ....
    }

According to this, algorithm of two matrices is something like this:

where I believe VectorMath's * operator represents ABin this equation. (meaning you can write A * B in swift to do same calculation.) If so, the function's lhs and rhs is reversed and since Matrix multiplication is not commutative, it'll produce different results.

I did write a simple Matrix4 <-> CATransform3D conversion code and check something like this:

    let m1 = Matrix4( /* init with some values */)
    let m2 = Matrix4( /* init with some other values */)

    let con1 = CATransform3DConcat(CATransform3D(m1), CATransform3D(m2) )
    let con2 = m1 * m2
    XCTAssertTrue(Matrix4(con1) == con2)  // this should pass, but fails

    let con3 = m2 * m1
    XCTAssertFalse(Matrix4(con1) == con3)  // this should pass, but fails

Here's what CATransform3DConcats document says:

Concatenate 'b' to 'a' and return the result: t' = a * b.

I think it would be better to have reversed order for those methods.

Swift 3 compatibility

Hey, I'd love to see this lib available in Swift 3 so I can implement it in my project.

Thanks 😄

Cocoapods

I'd be cool to also add Cocoapods support. I done this implementation myself last month for my library. Just follow this post and this checklist.

normalize() maybe wrong?

func normalized() -> Vector4 {
    let lengthSquared = self.lengthSquared
    if lengthSquared ~= 0 || lengthSquared ~= 1 {
        return self
    }
    return self / sqrt(lengthSquared)
}

should be " lengthSquared == 0 || lengthSquared == 1 "

Add support to OSX 10.11.1

I ran tests on OSX 10.11.1 but couldn't compile

Make extensions public

put the "public" keyword before the extension declarations, so that they export properly from bundle to bundle/app

example:

public extension SCNVector3 {
    init(_ v: Vector3) {
        self.init(x: SCNFloat(v.x), y: SCNFloat(v.y), z: SCNFloat(v.z))
    }
}

Quaternion <-> Euler angle converting back and forth does not return original value

Insert the following testing code to testEulerConversion test case and observe it to fail

let quat2 = Quaternion(pitch: 0.12334412, yaw: 1.3521468, roll: -0.53435323)
let (pitch, yaw, roll) = quat2.toPitchYawRoll()
let quat2Ref = Quaternion(pitch: pitch, yaw: yaw, roll: roll)
XCTAssertTrue(quat2 ~= quat2Ref)

Won't compile to Swift's new version