Evochron Legacy - Particle Weapon Physics...

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Evochron Legacy - Particle Weapon Physics...

Post by Vice »

This post provides some information on the reasoning behind particle weapon behavior in Evochron Legacy, which does have several changes that are new to the series.

During the latter stages of beta testing, a few testers mentioned that they wanted to see their ship's velocity transfer to their weapon fire shots. This was primarily due to enabling them to fire at targets ahead of them and have a fair chance of hitting the target while it was flying backwards.

Previously in Mercenary, no variables from the ship's speed or vector were transferred to particle gunfire shots. Such factors were entirely offset for gunfire shots so they always travelled at the same speed when fired, regardless of the velocity of the player's ship. The problem with this was that if a player flew backwards, they could fire back at a ship behind them while the forward moving attacker wasn't as likely to be hit because their shots would move slower relative to the player flying backwards. As long as a player didn't fall for the bait and fly in behind a backwards flying opponent, they wouldn't be so vulnerable. But in some potential situations, the mismatched speed would result in a condition where the backwards flying player had an advantage over the forward flying player.

In Legacy, this has been changed significantly. Velocity is now imparted to particle gunfire shots. This way, a player flying backwards can still be hit by a player flying forward at them... once they are in range of course. This is because the ship's velocity is now applied to the particle shots so if you fly forward at 1000, the system will apply around +1000 velocity to your shots the moment you pull the trigger. If you fly forward at 5000, then around +5000 is added. And the reverse also applies an adjusted negative factor to shots. So whether you fly at 100 or 4000, your shots will move out ahead of your ship at the same rate.

So what about vector? This was an aspect I wrestled with for a very long time. Eventually, after months of testing, the decision was made to provide physics offsets to particle shots so that they would maintain a consistent track along the gunsight's path exactly 1:1. If this wasn't done, gunfire would drift away from where the gunsight was pointing at the time the shots were fired, rather than continue to track directly toward where the gunsight was pointing. Here are some images to illustrate. In the first image, the ship's vector is transferred to the gunfire shots. This results in the shots drifting sideways at the same rate the player's ship does, resulting in a miss because the target wasn't travelling at exactly the same trajectory as the player's ship. Plus, the shots fail to go where the gunsight was pointing because of the imparted drift:
Image
In this second image, the particle shots go where the gunsight is pointing. This means that wherever the player aims, the gunshots will go there, regardless of how their ship is moving. The line of sight is maintained and the computer system does the work of offsetting the shots so they travel exactly along the path from the barrel to the point the gunsight is aiming precisely:
Image
So gunfire will always follow the track of the gunsight at the moment the trigger is pulled, regardless of how fast the player's ship is flying and in what direction. All the player has to do is focus on aiming the gunsight where they want their shots to go. The computer then does the work of making sure their shots follow the track of where they put the gunsight.

Even current modern weapon systems have a form of auto-offsetting for firing bullets at a target from an aircraft or vehicle that is moving. They compensate by simply aiming the barrel(s) at a different angle for their lead calculations. It's not unreasonable to expect that in the future, such technology will be improved upon and for energy based weapons, offsetting could be done internally as the particle charge is generated and fired. A charged energy burst could be rapidly shifted as it left the barrel, giving it the offset needed to precisely follow the track that the gunsight is aiming at the moment the pilot pulled the trigger.

So while vector is offset for precise 1:1 accuracy with gunsight tracking, velocity is imparted to the shot to provide the push/pull factor players wanted for the scenario above.
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