What is the new feature?

Improvements to modded rocket ammo.

• Examples of using AmmoID.Sets.SpecificLauncherAmmoProjectileMatches to provide weapon specific projectiles for specific ammo items, typical of rocket launchers but useable by any weapon.
• AmmoID.Sets.SpecificLauncherAmmoProjectileFallback allows for weapons to "inherit" ammo specific projectiles from other weapons, facilitating mod compatibility for these types of weapons.
• ProjectileID.Sets.Explosive[] to handle all of the things that Projecitle AI Style 16 (Explosive) did.
  • Sets the timeLeft to 3 and the projectile direction when colliding with an NPC or player in PVP (so the explosive can detonate).
  • Shimmer interaction: bounce off of the top of Shimmer and explode with no blast damage when hitting the sides or bottom.
  • Damage other players in the blast radius in For the Worthy worlds.
• Expose Projectile.PrepareBombToBlow and add Mod/GlobalProjectile.PrepareBombToBlow hooks to facilitate modded explosives, allowing explosives to properly adjust properties when exploding.
• Projectile.HurtPlayer(Rectangle hitbox). A simplified copy of Projectile.BombsHurtPlayers() which damages the local player if they intersect with the hitbox.

Why should this be part of tModLoader?

Rocket ammo is very strange and isn't as intuitive as arrow and bullet ammo. Rocket ammo was quite difficult to deal with because each launcher in vanilla has its own behavior depending on the ammo type. Interaction between mods with custom rocket ammo types were also questionable.

What are the changes to ExampleMod?

Added Example Rocket based on Rocket I which includes ExampleRocket item, ExampleRocketLauncher item, ExampleRocketProjectile, ExampleGrenadeProjectile, ExampleProximityMineProjectile, and ExampleSnowmanRocketProjectile.

Even though this is based on Rocket I, I included a few comments about things from Rocket III, Mini Nuke I, and how to destroy tiles like Rocket II.

This PR also updates ExampleExplosive: Updating its sprite, adding Shimmer interaction, adding the new ProjectileID.Sets.PlayerHurtDamageIgnoresDifficultyScaling set, and making the projectile damage the player.

Are there alternative designs?

• I thought the ProjectileID.Sets.Explosive would handle damaging other players in For the Worthy worlds, but it seems like it doesn't because the vanilla Kill() isn't called on ModProjectiles? Might need some more investigation. So, the parts in the projectiles that resize the projectile and damage the player in For the Worthy worlds may or may not be necessary.

Do these changes need additional documentation?

Shouldn't contain any breakage. Any projectile using Projectile AI Style 16 will still work as before. Using PickAmmo() instead of ProjectileID.Sets.SpecificLauncherAmmoProjectileMatches should still work.

Short Summary

• ProjectileID.Sets.Explosive[] to match the behavior of vanilla explosives without having to use aiStyle 16
• New Projectile.HurtPlayer(Rectangle hitbox) method which will damage the local player if they intersect the hitbox.
• New PrepareBombToBlow hook to implement explosives correctly.
• A full set of rocket projectiles as well as rocket launcher and rocket ammo items, showing how they all connect to each other.

Porting Notes

• If you were using Projectile.aiStyle = ProjAIStyleID.Explosive (16) to match the vanilla behavior of explosives, you can now use ProjectileID.Sets.Explosive[]. Also override PrepareBombToBlow and add the explosion resizing logic there.
• Rocket ammo should have ProjectileID.Sets.SpecificLauncherAmmoProjectileMatches defined for all applicable vanilla launchers.
• Rocket launchers should set AmmoID.Sets.SpecificLauncherAmmoProjectileFallback to the closest vanilla launcher to inherit ammo-specific projectiles from.
• If you were using PickAmmo() or similar to fix your rocket ammo shooting the wrong projectile for the Snowman Cannon and Celebration Mk2, double check that because it is probably not necessary anymore.