General: Mark member functions as const where applicable

These don't modify internal member state, so they can be const.

include/zeus/COBBox.hpp

@@ -46,6 +46,6 @@ public:
 
   bool OBBIntersectsBox(const COBBox& other) const;
 
-  bool AABoxIntersectsBox(const CAABox& other) { return OBBIntersectsBox(FromAABox(other, CTransform())); }
+  bool AABoxIntersectsBox(const CAABox& other) const { return OBBIntersectsBox(FromAABox(other, CTransform())); }
 };
 } // namespace zeus

include/zeus/CQuaternion.hpp

@@ -199,7 +199,7 @@ public:
     z() = i.z();
   }
 
-  CRelAngle angleFrom(const zeus::CQuaternion& other);
+  CRelAngle angleFrom(const zeus::CQuaternion& other) const;
 
   simd<float>::reference operator[](size_t idx) {
     assert(idx < 4);

include/zeus/CTransform.hpp

@@ -52,14 +52,14 @@ public:
 
   static CTransform Translate(float x, float y, float z) { return Translate({x, y, z}); }
 
-  CTransform operator+(const CVector3f& other) { return CTransform(basis, origin + other); }
+  CTransform operator+(const CVector3f& other) const { return CTransform(basis, origin + other); }
 
   CTransform& operator+=(const CVector3f& other) {
     origin += other;
     return *this;
   }
 
-  CTransform operator-(const CVector3f& other) { return CTransform(basis, origin - other); }
+  CTransform operator-(const CVector3f& other) const { return CTransform(basis, origin - other); }
 
   CTransform& operator-=(const CVector3f& other) {
     origin -= other;

include/zeus/CVector2f.hpp

@@ -172,7 +172,7 @@ public:
 
   bool isZero() const { return magSquared() <= FLT_EPSILON; }
 
-  bool isEqu(const CVector2f& other, float epsilon = FLT_EPSILON) {
+  bool isEqu(const CVector2f& other, float epsilon = FLT_EPSILON) const {
     const CVector2f diffVec = other - *this;
     return (diffVec.x() <= epsilon && diffVec.y() <= epsilon);
   }

include/zeus/CVector3d.hpp

@@ -29,7 +29,7 @@ public:
 
   constexpr CVector3d(double x, double y, double z) : mSimd(x, y, z) {}
 
-  CVector3f asCVector3f() { return mSimd; }
+  CVector3f asCVector3f() const { return mSimd; }
 
   double magSquared() const { return mSimd.dot3(mSimd); }
 
@@ -41,7 +41,7 @@ public:
 
   double dot(const CVector3d& rhs) const { return mSimd.dot3(rhs.mSimd); }
 
-  CVector3d asNormalized() {
+  CVector3d asNormalized() const {
     double mag = magnitude();
     mag = 1.0 / mag;
     return mSimd * zeus::simd<double>(mag);

include/zeus/CVector3f.hpp

@@ -180,7 +180,7 @@ public:
     return v;
   }
 
-  bool isEqu(const CVector3f& other, float epsilon = FLT_EPSILON) {
+  bool isEqu(const CVector3f& other, float epsilon = FLT_EPSILON) const {
     const CVector3f diffVec = other - *this;
     return (diffVec.x() <= epsilon && diffVec.y() <= epsilon && diffVec.z() <= epsilon);
   }

include/zeus/CVector4f.hpp

@@ -166,7 +166,7 @@ public:
            std::fabs(w()) >= FLT_EPSILON;
   }
 
-  bool isEqu(const CVector4f& other, float epsilon = FLT_EPSILON) {
+  bool isEqu(const CVector4f& other, float epsilon = FLT_EPSILON) const {
     const CVector4f diffVec = other - *this;
     return (diffVec.x() <= epsilon && diffVec.y() <= epsilon && diffVec.z() <= epsilon && diffVec.w() <= epsilon);
   }

src/CQuaternion.cpp

@@ -226,7 +226,7 @@ CQuaternion CQuaternion::buildEquivalent() const {
     return CQuaternion::fromAxisAngle(CUnitVector3f(mSimd.shuffle<1, 2, 3, 3>()), tmp + 2.0 * M_PI);
 }
 
-CRelAngle CQuaternion::angleFrom(const zeus::CQuaternion& other) {
+CRelAngle CQuaternion::angleFrom(const zeus::CQuaternion& other) const {
   return std::acos(zeus::clamp(-1.f, dot(other), 1.f));
 }