Can transform->_angle be greater than 360 here (I suppose so since otherwise the modulo seems pointless)? If so, this is dangerous.
For example, think of the following code:
```
unsigned int angle = 400;
unsigned int test = (360 - angle) % 360;
printf("%u %u\n", 360 - angle, test);
```
It will result in test being 216 (the precise output over here is: 4294967256 216). The reason for his surprising behavior (at least I would expect you expect it to end up with -40/320) is that the substraction underflows the unsigned type. Actually, there is also a potentional issue when you use signed types because the sign of the result is implementation dependant in C98 when only one of the two operands is negative IIRC (you would need to check up if that's really an issue).

If you want to handle transform->_angle values > 360 I would suggest to use:
```
uint32 invAngle = 360 - (transform->_angle % 360);
```
instead. This will assure invAngle to be the correct result in the range [0, 360]. It will also be free of potentional implementation specific behavior.