In addition to these, take a look at the ZDoom forums project thread for some more development news.

• Building a project with BDLite
• Structure of BDLite weapons
• Structure of BDLite monsters
• Blood and gibs
• Adding a new BDLite weapon - Revolver
• Adding a new BDLite monster - Zombie Plasma Scientist

Adding a new BDLite monster - Zombie Plasma Scientist

One of the biggest inspirations behind doing the BDLite overhaul was a comment on the first release of my "Vulkan" episode - that it was too easy to notice the difference between the complex hitboxes and death animations of the standard enemies and the relative plainness of the enhanced ones. When rewriting the monster and blood code, I wanted to achieve a compromise where monsters seemed reactive and varied like Brutal Doom, but making sure that adding a new one wasn't a completely insurmountable task like it used to be. Take a look at the Structure of BDLite Monsters tutorial for an overview of what a new BDLite monster should include in its sprites and code.

For this example, I'll complete a circle by enhancing the Zombie Plasma Scientist that was in the original Vulkan and which was subsequently improved by Enjay with more rotations, brightmaps and so on. See the tutorial on making the Revolver for how to lay out and combine the new monster resources with the base BDLite PK3 - you can see the final enhanced enemy in Vulkan 1.5.

After unpacking the enemy from the WAD into the folder that's to become our PK3, we already have a ton of sprites. I'm very grateful to Enjay for building on my mediocre spriting skills and doing the rotations in particular - I'd chosen to give him a missing left arm primarily because that meant I wouldn't have to draw it, but that made it very obvious when the sprite was flipped to fill out the rotations. Let's go in and make some more.

I could never pass as a genuine spriter, but through perseverance, trial and error, I can at least edit things around a bit. Most of these came from splicing together existing frames from the scientist with gore frames from Brutal Doom and pulling the results around until they looked somewhat convincing. Really, very few sprites are required to allow for a reasonable number of death types - we've got a set of sprites for being bowled over backwards (as well as forwards as in the standard death animation), some body parts and dismemberments of two levels of severity. I'm also fortunate that so many of the scientist enemies in Vulkan share exactly the same body, just with the heads and weapons being different - it means I can use these same sprites for many of them.

This is what the scientist's DECORATE looks like straight out of the WAD on Realm667. It's a fairly simple vanilla-style enemy that defines its own projectiles - the main thing that we'll be doing to it is expanding those Death and XDeath states to make them more spectacular.

Let's define some flying body parts first, which will be spawned by several of our death states - these extend from BdGib and follow a simple pattern, with most of the work being done by the base class. Check the Blood and Gibs tutorial for how these work - all that we need here is to define a flying sprite, tell it to roll, splash when it hits the ground and define its lying-around sprite. Again, these are shared by most of the scientist enemies in Vulkan.

As mentioned in the Structure of BDLite Monsters, a BDLite monster's death states come in two parts - the Death.* states that the monster jumps to when its health reaches zero or below, and the Die states which perform the death animations. The Die states are the easiest to explain first, so here are a collection of them for this monster.

Even with a relatively small number of gore frames (and nowhere near the hundreds that were present in the original Brutal Doom), we've got eight different death animations for the scientist. In the actual DECORATE file, the DieNormal2 and DiePlasma states are inherited from an AbstractZombieScientist, making the code a bit shorter still. The labels for these animations are:

• DieNormal - I tend to use this label for the normal death animation that you might see in vanilla Doom.
• DieNormal2 - Another unspectacular death animation - this is for the monster keeling over backwards instead of forwards.
• DieRollBack - Uses the same frames as DieNormal2, but kicks the monster back and upwrads using ThrustThingZ and A_Recoil. This is used for being hit with weapons with more of a punch, such as the shotgun.
• DiePlasma - Uses PBR1, a skeletal sprite in the base BDLite, to show the monster melting from the plasma fire.
• DieJustLegs - The monster is reduced to a pair of legs that fall over. For this die state and the ones below, we start spawning our specific scientist gib objects using A_CustomMissile, along with a collection of generic gibs that can be used on any monster. Again, see the Blood and Gibs tutorial for more on what all these items do - you can use as few or as many as you like.
• DieSplit - The monster splits down the middle and falls over (flipped from the DieJustLegs frames to give a bit more variety to the appearance of the last state).
• DieGibs - This is equivalent in appearance to XDeath in Vanilla Doom, with some enhancements - we use the "gibbing" animation common to many of the smaller enemies in Doom, and spawn some additional items.
• XDeath - The most severe of the states, reached automatically by the monster's health being reduced far beyond zero as well as explicitly (hence we perform XScream, NoBlocking and so on here - most of the time they're handled in the section described next). The monster absolutely explodes and is removed from the game, replaced with a ton of gibs.

The other major change we have to make to the DECORATE file is to get the monster to play these animations when it dies. In ZDoom, the monster will jump to the label called "Death" when its health is reduced to zero - or if available, the state called "Death.[damage type]" according to the projectile or attack that killed it. We can use these to define an array of possible death states to jump to from each damage type that the player can cause in BDLite.

Each major damage type performs the usual stuff to indicate a monster death, then uses A_Jump to jump to a "die" state appropriate to that weapon's damage. Lighter weapons like the rifle will cause relatively unspectacular death animations, whereas big ones like the explosives will cause the gib-spawning ones. This pattern utilizes a handy feature of the A_Jump function - we use 256 as the first parameter to make it always jump to somewhere, but as we provide a list of labels, ZDoom will jump to a randomly chosen one. Without this, we'd have to do much more with A_JumpIf and it would be much less neat.

And so here's the final BDLite-ized version of the scientist. Again, the Death states are shared between many scientist enemies so they're in the AbstractZombieScientist class, shortening the length of this one. I've also removed its DoomEd number (which is defined in MAPINFO instead) and changed its drop item to a SingleCell because they're used so often in Vulkan that dropping a Cell every time would be complete overkill.