Add Value.patch()

Author: zicklag

assets/scripts/breakout.ts

@@ -34,9 +34,19 @@ function run() {
       world.insert(item.entity, Value.create(Ball));
 
       // Create a velocity component
+      //
+      // We can optionally include a patch to the default value of velocity as the second argument
+      // to create().
       let vel = Value.create(Velocity, [
         {
           x: -200,
+        },
+      ]);
+
+      // For demonstration purposes, we can also patch values after they have been created. This
+      // works on any ECS component, not just ones created with Value.create().
+      Value.patch(vel, [
+        {
           y: 200,
         },
       ]);

src/runtime/ops/ecs.rs

@@ -40,6 +40,7 @@ pub fn insert_ecs_ops(ops: &mut OpMap) {
         "ecs_value_ref_default",
         Box::new(value::ecs_value_ref_default),
     );
+    ops.insert("ecs_value_ref_patch", Box::new(value::ecs_value_ref_patch));
     ops.insert(
         "ecs_component_insert",
         Box::new(component::ecs_component_insert),

src/runtime/ops/ecs/ecs.js

@@ -187,6 +187,10 @@
         create(type, patch) {
             return Value.wrapValueRef(bevyModJsScriptingOpSync("ecs_value_ref_default", type.typeName, patch));
         },
+
+        patch(value, patch) {
+            Value.wrapValueRef(bevyModJsScriptingOpSync("ecs_value_ref_patch", Value.unwrapValueRef(value), patch));
+        }
     }
 
     const world = new World();

src/runtime/ops/ecs/value.rs

@@ -364,6 +364,32 @@ pub fn ecs_value_ref_default(
     Ok(serde_json::to_value(value_ref)?)
 }
 
+pub fn ecs_value_ref_patch(
+    context: OpContext,
+    world: &mut bevy::prelude::World,
+    args: serde_json::Value,
+) -> anyhow::Result<serde_json::Value> {
+    // Parse args
+    let (value_ref, patch): (JsValueRef, serde_json::Value) =
+        serde_json::from_value(args).context("parse args")?;
+
+    let value_refs = context
+        .op_state
+        .entry::<JsValueRefs>()
+        .or_insert_with(default);
+
+    let value_ref = value_refs
+        .get_mut(value_ref.key)
+        .ok_or_else(|| format_err!("Value ref does not exist"))?;
+
+    let mut value = value_ref.get_mut(world)?;
+
+    // Patch the default value if a patch is provided
+    patch_reflect_with_json(value.as_reflect_mut(), patch)?;
+
+    Ok(serde_json::Value::Null)
+}
+
 pub fn ecs_value_ref_call(
     context: OpContext,
     world: &mut bevy::prelude::World,

types/lib.bevy.d.ts

@@ -24,6 +24,7 @@ declare type RawValueRef = unknown;
 
 declare interface ValueGlobal {
   create<T>(t: BevyType<T>, patch?: any): T;
+  patch<T>(value: any, patch: any): T;
 }
 
 declare let Value: ValueGlobal;