Initial work on attack scripting system

src/scripting/move_compiler.rs

@@ -0,0 +1,177 @@
+use std::{cell::RefCell, collections::HashMap, rc::Rc};
+
+use rhai::EvalAltResult;
+
+use crate::{
+    fighter::attack::{self, AttackAngle, FighterDamage, Knockback, KnockbackType},
+    math::{int::FGi32, vec::FGVec2, vec3::FGVec3},
+};
+
+#[derive(Debug, Default)]
+struct MoveCompiler {
+    hitboxes: HashMap<u32, attack::AttackHitbox>,
+    active_hitboxes: Vec<u32>,
+    cursor: u32,
+}
+
+impl MoveCompiler {
+    fn frame(&mut self, new_frame: u32) -> Result<(), Box<EvalAltResult>> {
+        if new_frame < self.cursor {
+            return Err(format!(
+                "Tried to go back from frame {} -> {}, rolling back is not supported",
+                self.cursor, new_frame
+            )
+            .into());
+        }
+
+        self.cursor = new_frame;
+
+        Ok(())
+    }
+
+    fn remove_hitbox(&mut self, id: u32) -> Result<(), Box<EvalAltResult>> {
+        let hb = self
+            .hitboxes
+            .get_mut(&id)
+            .ok_or(format!("Can't remove hitbox with {id}: Hitbox not found"))?;
+
+        let active_hbox_position =
+            self.active_hitboxes
+                .iter()
+                .position(|i| *i == id)
+                .ok_or(format!(
+                    "Can't remove hitbox with ID {id}: Hitbox was not active"
+                ))?;
+
+        hb.end_frame = self.cursor;
+
+        self.active_hitboxes.remove(active_hbox_position);
+
+        Ok(())
+    }
+    fn remove_all_hitboxes(&mut self) -> Result<(), Box<EvalAltResult>> {
+        // We are gonna modify the array, so take a copy...
+        for hitbox_id in self.active_hitboxes.clone() {
+            self.remove_hitbox(hitbox_id)?;
+        }
+
+        self.active_hitboxes.clear();
+
+        Ok(())
+    }
+}
+
+// scripting functions
+
+pub fn register_common_types(engine: &mut rhai::Engine) {
+    engine
+        .register_type_with_name::<KnockbackType>("KnockbackType")
+        .register_fn("knockback_normal", KnockbackType::make_normal)
+        .register_fn("knockback_fixed", KnockbackType::make_fixed)
+        .register_type_with_name::<AttackAngle>("Angle")
+        .register_fn("angle", AttackAngle::make_normal)
+        .register_fn("angle_sakurai", AttackAngle::make_sakurai)
+        .register_type_with_name::<Knockback>("Knockback")
+        .register_fn("knockback", Knockback::lit)
+        .register_type_with_name::<FGi32>("FGi32")
+        .register_fn("fg32", FGi32::lit)
+        .register_type_with_name::<FGVec2>("Vec2")
+        .register_fn("vec2", FGVec2::lit)
+        .register_type_with_name::<FGVec3>("Vec3")
+        .register_fn("vec3", FGVec3::lit)
+        .register_type_with_name::<FighterDamage>("FighterDamage")
+        .register_fn("damage", FighterDamage::lit);
+}
+
+pub fn compile_script(text: &str) -> Result<MoveCompiler, String> {
+    let mc = Rc::new(RefCell::new(MoveCompiler {
+        cursor: 0,
+        ..Default::default()
+    }));
+    let mut engine = rhai::Engine::new();
+
+    register_common_types(&mut engine);
+
+    {
+        let mc = mc.clone();
+        engine.register_fn(
+            "frame",
+            move |frame: i64| -> Result<(), Box<EvalAltResult>> {
+                let mut b = mc.borrow_mut();
+                b.frame(frame as u32)
+            },
+        );
+    }
+
+    {
+        let mc = mc.clone();
+        engine.register_fn(
+            "remove_all_hitboxes",
+            move || -> Result<(), Box<EvalAltResult>> {
+                let mut b = mc.borrow_mut();
+                b.remove_all_hitboxes()
+            },
+        );
+    }
+
+    {
+        let mc = mc.clone();
+        engine.register_fn(
+            "remove_all_hitboxes",
+            move |id: i64| -> Result<(), Box<EvalAltResult>> {
+                let mut b = mc.borrow_mut();
+                b.remove_hitbox(id as u32)
+            },
+        );
+    }
+
+    {
+        let mc = mc.clone();
+        engine.register_fn(
+            "hitbox",
+            move |id: i64,
+                  bone: &str,
+                  damage: FighterDamage,
+                  offset: FGVec3,
+                  radius: FGi32,
+                  angle: AttackAngle,
+                  knockback_type: KnockbackType,
+                  knockback: Knockback,
+                  knockback_growth: FGi32|
+                  -> Result<(), Box<EvalAltResult>> {
+                let mut b = mc.borrow_mut();
+
+                // Rhai does not have first class u32 support, so we have to do this.
+                let id = id as u32;
+
+                if b.hitboxes.contains_key(&id) {
+                    return Err(format!("Hitbox with ID {} already existed!", id).into());
+                }
+
+                let hitbox = attack::AttackHitbox {
+                    id,
+                    bone: bone.to_owned(),
+                    damage,
+                    offset,
+                    radius,
+                    angle,
+                    knockback_type,
+                    knockback,
+                    knockback_growth,
+                    start_frame: b.cursor,
+                    end_frame: b.cursor,
+                };
+
+                b.hitboxes.insert(id, hitbox);
+                b.active_hitboxes.push(id);
+
+                Ok(())
+            },
+        );
+    }
+
+    engine
+        .run(&text)
+        .map(|_| Rc::into_inner(mc).unwrap().into_inner())
+        .map_err(|err| err.to_string())
+}