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Add NewQuatEulerXYZ+better comments

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bloeys
2022-05-22 20:14:01 +04:00
parent f3db256007
commit e45e4d3304
2 changed files with 35 additions and 2 deletions
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31
gglm/quat.go
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@ -16,7 +16,7 @@ func (q *Quat) Eq(q2 *Quat) bool {
return q.Data == q2.Data
}
//Angle returns the angle represented by this quaternion
//Angle returns the angle represented by this quaternion in radians
func (q *Quat) Angle() float32 {
if Abs32(q.Data[3]) > CosHalf {
@ -74,7 +74,34 @@ func NewQuatEuler(v *Vec3) *Quat {
}
}
//AngleAxis rotates rotRad radians around the *normalized* vector rotAxisNorm
//Euler takes rotations in radians and produces a rotation that
//rotates around the z-axis, y-axis and lastly x-axis.
func NewQuatEulerXYZ(x, y, z float32) *Quat {
//Some other common terminology: x=roll, y=pitch, z=yaw
sinX, cosX := Sincos32(x * 0.5)
sinY, cosY := Sincos32(y * 0.5)
sinZ, cosZ := Sincos32(z * 0.5)
//This produces a z->y->x multiply order, but its written as XYZ.
//This is due to XYZ meaning independent rotation matrices, so Z is applied
//first, then Y matrix and lastly X.
//See this for more info: https://github.com/godotengine/godot/issues/6816#issuecomment-254592170
//
//Note: On most conversion tools putting the multiply order (e.g. ZYX for us) is required.
return &Quat{
Vec4: Vec4{
Data: [4]float32{
sinX*cosY*cosZ - cosX*sinY*sinZ,
cosX*sinY*cosZ + sinX*cosY*sinZ,
cosX*cosY*sinZ - sinX*sinY*cosZ,
cosX*cosY*cosZ + sinX*sinY*sinZ,
},
},
}
}
//NewQuatAngleAxis produces a quaternion thats rotates rotRad radians around the *normalized* vector rotAxisNorm
func NewQuatAngleAxis(rotRad float32, rotAxisNorm *Vec3) *Quat {
s, c := Sincos32(rotRad * 0.5)