Transform::combine is not robust.

[Des-Nerger]

Not any two Transforms can be combined into one.
For instance, you can't combine these two:
Tranform(vec3(0, 0, 0), angleAxis(45.0f * QUAT_DEG2RAD, vec3(0, 0, 1)), vec3(1, 1, 1))
Tranform(vec3(0, 0, 0), quat(), vec3(1, 0.5, 1))
To illustrate, here's an example of applying these two Transforms to an axis-aligned square with the origin in the center:
So Transform::combine doesn't give the expected result in this case.

Possible solutions:

1. Either narrow the definition of Transform to prohibit non-uniform scales:

struct Transform {
	vec3 position;
	quat rotation;
	float scale;

2. Or the opposite: widen the definition:

struct Transform {
	vec3 position;
	mat3 linear;

3. Or give up the idea of implementing Transform::combine at all.