1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206
use darling::FromDeriveInput; use quote::quote; use syn::{parse_macro_input, DeriveInput}; use action::Action; use consideration::Consideration; mod action; mod consideration; /** `Action`s in `big-brain` are defined through this derive macro. Once defined, they can be freely used in a .ron file. They define actual behaviors that an `actor` will perform when the Thinker engine picks it as the active action, based on [Considerations](derive.Consideration.html). ## Definition Example ```ignore use specs::{Component, Entity, System, WriteStorage}; use big_brain::{Action, ActionState}; // These are your game's components. use crate::components; // This will be used to create `Action` components. They MUST implement the // `specs::Component` trait. #[derive(Debug, Clone, Component, Action)] pub struct Eat { // All actions **must** have a public `actor` field. This will be populated // with the actual actor performing the Action. The `Entity` associated with // the `Action` itself is distinct from the actor. pub actor: Entity, // `default` fields will be populated using default::Default() when the // Action is instantiated. These cannot be used as params. #[action(default)] pub foo: f32, // `param` fields will be populated using the value passed in through the // `.ron` file. #[action(param)] pub reduce_by: f32, } // Once an Action component is defined, we define a System that can act on it. pub struct EatSystem; impl<'a> System<'a> for EatSystem { type SystemData = ( WriteStorage<'a, components::Hunger>, // This is the actual Eat component. WriteStorage<'a, Eat>, // An ActionState component is attached to every Action Entity. // It contains the current running status of the Action, and will be // updated as needed by the actor's Thinker. WriteStorage<'a, ActionState>, ); fn run(&mut self, (mut hungers, mut eat_actions, mut states): Self::SystemData) { // You can join the Eat and ActionState together. They're on the same component. for (state, eat_action) in (&mut states, &mut eat_actions).join() { // Any components attached to the actor must be fetched separately. if let Some(hunger) = hungers.get_mut(eat_action.actor.clone()) { match state { // At the very least, every Action should handle the // `Requested` state. ActionState::Requested => { hunger.hunger -= eat_action.reduce_by; // Success tells the Thinker that this action succeeded! *state = ActionState::Success; } // Make sure to handle Cancelled for long-running Actions. // The Thinker will not continue until the state is either // Success or Failure. ActionState::Cancelled => { *state = ActionState::Failure; } _ => {} } } } } } ``` ## Usage Example ```ignore ( picker: {"FirstToScore": ()}, // Actions are defined using the `then` param to Choices choices: [( consider: [{"Hunger": ()}], // We can use the param defined in our derive definition here. // The `foo` field will be defaulted and cannot be defined here. then: {"Eat": (reduce_by: 80.0)}, )] ) ``` */ #[proc_macro_derive(Action, attributes(action))] pub fn derive_action_builder(input: proc_macro::TokenStream) -> proc_macro::TokenStream { let input = parse_macro_input!(input as DeriveInput); let action = Action::from_derive_input(&input).unwrap(); quote!(#action).into() } /** `Consideration`s in `big-brain` are defined through this derive macro. Once defined, they can be freely used in a .ron file. While `Action`s define behaviors, `Consideration`s are used to determine _whether_ to execute a certain action. `Consideration`s are responsible for determining a specific `Utility`, or score, in Utility AI terms. This score is what sets Utility AI apart from plain old Behavior Trees. Like anything else in an Entity system, considerations and their behaviors consist of a `Component` and an associated `System`. ## Definition Example ```ignore use specs::{Component, Entity, ReadStorage, System, WriteStorage}; use big_brain::{Consideration, Utility}; // These are your game's components. use crate::components; // `Consideration`s are defined by deriving them -- they MUST be Components. #[derive(Debug, Component, Consideration)] pub struct Hunger { // All considerations **must** have a public `actor` field. This will be populated // with the actual actor considering the world around it The `Entity` associated with // the `Consideration` itself is distinct from the actor. pub actor: Entity, // `default` fields will be populated using default::Default() when the // Consideration is instantiated. These cannot be used as params. #[consideration(default)] pub evaluator: PowerEvaluator, // `param` fields will be populated using the value passed in through the // `.ron` file. #[consideration(param)] pub weight: f32, } pub struct ConsiderHunger; impl<'a> System<'a> for ConsiderHunger { type SystemData = ( ReadStorage<'a, components::Hunger>, // This is the actual `Consideration` component. WriteStorage<'a, Hunger>, // The `Utility` component associated with this `Consideration` holds // the current calculated score for that consideration. WriteStorage<'a, Utility>, ); fn run(&mut self, (hungers, mut considerers, mut utilities): Self::SystemData) { // Join the considerations with the utilities -- they share an `Entity`. for (conser, util) in (&mut considerers, &mut utilities).join() { // Any actor-related components must be fetched separately, based on // the consideration's `actor`. if let Some(hunger) = hungers.get(conser.actor.clone()) { *util = Utility { // values and weights can be arbitrary numbers. The final // score is based on combining these two values. // // Utilities with weight `0.0` are not used. // // For the formula, refer to the docs on `WeightedMeasure`. value: conser.evaluator.evaluate(hunger.hunger), weight: conser.weight, }; } } } } ``` ## Usage Example ```ignore ( picker: {"FirstToScore": ()}, choices: [( // Considerations to use are defined using the `consider` param in choices. // A choice can have zero or more considerations. consider: [{"Hunger": (weight: 1.0)}], // This is the action that will be executed if this choice "wins". then: {"Eat": ()}, )] ) ``` */ #[proc_macro_derive(Consideration, attributes(consideration))] pub fn derive_consideration_builder(input: proc_macro::TokenStream) -> proc_macro::TokenStream { let input = parse_macro_input!(input as DeriveInput); let consideration = Consideration::from_derive_input(&input).unwrap(); (quote!(#consideration)).into() }