I got sidetracked.
I was working on tying volumes to bones in order to calculate mass from volume and density, when I suddenly realised I was going to have to get density from somewhere. I was this close to following the original plan and adding a simple constant “creature density” value to the game… but…
Well, quite frankly, I’m tired of making placeholders and putting the interesting stuff off until I’ve finished the boring stuff. So I decided not to, and dived headfirst into the new material system. I wonder how many of these I can fit in? Any preferences?
My initial thought was to take a leaf out of Dwarf Fortress’ book, and define materials generically, to amplify the possibility of weird, interesting and utterly horrific combinations. The problem with this, though, is that they need to texture differently depending on how they’re applied, especially for things like fur and claws. So it’s more likely we’ll need to split them up based on how they’re applied…
– The furry/feathery/skinny/slimy surface covering. Has a strong influence on friction and insulation. Mass determined by Surface Area * Thickness * Density. Immediately visually apparent by virtue of body texture, obviously.
– The goo and meat and muscle inside the creatures body. Influences the creatures strength and flexibility, as well as their optimal operating temperature and how endothermic they are. Mass determined by Volume * Density. Visual markers are mouth-textures and corpse meat textures.
• Hard Tissue
– Skeleton and weapons (I’ll probably split these into two seperate items, so a creature can have different claw and bone material). Density and compressive/shear strength will be the most influential settings for the skeleton, while density and sharpness will be important for weapons and chewing. Visible on hands and feet, teeth and in corpse bone textures.
These three categories will make up the outer covering (fur, feathers, skin), inner covering/organs (fibrous, porous, fatty) and skeleton/claws/teeth (keratin, chitin, osseous tissue, enamel), respectively. Each item will have its own texture/spritesheet, and a position in the mutation map.
I will likely have to have duplicates so as to allow, for example, chitin to be used as either endoskeleton or exoskeleton. One idea I’m leaning towards is storing materials as three texture objects in the same asset folder, so chitin could be a single Material asset but still be applied as Skin, Flesh or Hard Tissue. I imagine making your internal organs and muscles out of chitin wouldn’t end well, but why should we stop creatures from trying?
And as a bonus, this means creatures can have body coverings and flesh made entirely out of materials I hadn’t considered before now, like fibrous muscle, or bone tissue, or eyeball fluid or retina cords!
Wow. I am a horrible person.
This material system will likely become one of the sources of tangential learning for Species. Much the same as how playing Dwarf Fortress is an extremely effective way to drill into you what Magnetite, Hematite and Limonite are, Species will happily throw a bunch of terms I’ve stolen from Wikipedia at you until you bloody well remember what Osseous Tissue is, damn it.
The system will also have a few additional per-material values. Most of these will be placeholders until their appropriate systems are in place, but it doesn’t hurt in the long run to define them early. So far ‘m thinking these ones look good:
Compressive, Tensile and Shear Strength,
YieldRatio (a simpler way to represent Compressive, Tensile and Shear Yield Strength),
Coefficient Of Friction,
IgnitionTemperature, BurningEmission (that is, the amount of heat this material will emit while burning),
Melting and Boiling Point,
Thermal Capacity and Conductivity,
OperatingTemperature (flesh and muscle specific: determines the optimal body temperature for this creature),
HeatOutput (per unit of mass. This will be what establishes Endotherminess!),
Of course, finding values some of these numbers is gonna be all sorts of fun. “What’s the compression strength of fibrous muscle? What’s the melting point of eyeball fluid?” It won’t be easy, but there’s plenty of dogs and cats in the area.
Or, y’know, I could just ask The Google. But where’s the fun in that?
(Edit) Oh wow. I think I promised to let somebody kick me if I did exactly what I’m doing right now.
Yep. Yep I did. Who wants to do the honours?