Added lookat

Nuake/src/Core/Maths.cpp

@@ -2,9 +2,55 @@
 
 using namespace Nuake;
 
+Quat Nuake::LookAt(Vector3 sourcePoint, Vector3 destPoint)
+{
+    Vector3 forwardVector = glm::normalize(destPoint - sourcePoint);
+
+    float dot = glm::dot(Vector3(0, 0, 1), forwardVector);
+    if (glm::abs(dot - (-1.0f)) < 0.000001f)
+    {
+        return Quat(0, 1, 0, 3.1415926535897932f);
+    }
+    if (glm::abs(dot - (1.0f)) < 0.000001f)
+    {
+        return Quat(); // identity
+    }
+
+    float rotAngle = acos(dot);
+    Vector3 rotAxis = glm::cross(Vector3(0, 0, 1), forwardVector);
+    rotAxis = glm::normalize(rotAxis);
+    return CreateFromAxisAngle(rotAxis, rotAngle);
+}
+
+// just in case you need that function also
+Quat Nuake::CreateFromAxisAngle(Vector3 axis, float angle)
+{
+    float halfAngle = angle * .5f;
+    float s = sin(halfAngle);
+    Quat q;
+    q.x = axis.x * s;
+    q.y = axis.y * s;
+    q.z = axis.z * s;
+    q.w = cos(halfAngle);
+    return q;
+}
+
 Quat Nuake::QuatFromEuler(float x, float y, float z)
 {
-	return Quat(Vector3(Rad(z), Rad(y), Rad(x)));
+    Quat q;
+
+    float cr = cos(x * 0.5);
+    float sr = sin(x * 0.5);
+    float cp = cos(y * 0.5);
+    float sp = sin(y * 0.5);
+    float cy = cos(z * 0.5);
+    float sy = sin(z * 0.5);
+
+    q.w = cr * cp * cy + sr * sp * sy;
+    q.x = sr * cp * cy - cr * sp * sy;
+    q.y = cr * sp * cy + sr * cp * sy;
+    q.z = cr * cp * sy - sr * sp * cy;
+    return q;
 }
 
 Vector3 Nuake::QuatToDirection(const Quat& quat)