Projectiles have no actual collision detection

[Aritra Chakraborty]

Projectiles are purely graphical (and are indeed Local entities) and do not perform actual collision detection. This means they go through all obstructions on the way to their target, and also cannot hit "behind" the target if that is missed in a flat trajectory, requiring hacks such as the "linear splash" damage for bolt shooters.

The actual "hit" is handled via timers and DelayedDamage, completely irrespective of what the projectile is doing. There is primitive collision detection there (see #5964).

Relates to #5965 also.

[Erik Johansson]

I'm pretty sure this is intentional, the amount of work needed to get this working is higher than the relatively low level of additional realism.

[historic_bruno]

Replying to feneur:

I'm pretty sure this is intentional, the amount of work needed to get this working is higher than the relatively low level of additional realism.

Yeah, I don't see this changing any time soon, but I wouldn't mind seeing a better accuracy calculation for ranged units based on distance, possibly visual obstructions, and other factors.

[historic_bruno]

It was discussed in IRC ​yesterday, that instead of arbitrary entities blocking a projectile (requiring messy slow collision detection), we could just make this a visual effect. Projectiles would have their initial angle set according to calculated static obstruction heights between them and the target. The accuracy and timing would be unaffected. I don't know if we'll do this for all structures, but at least walls was suggested.