Improve serialization format of EffectAsset (#294)

This change makes a few improvements to the serialized representation of
an `EffectAsset`:
- `LiteralExpr`, `ExprHandle`, and `Module` are now
  `#[serde(transparent)]`, which makes them less verbose.
- `VectorValue` is serialized as its glam math type representation,
  making it a lot more readable in text format (_e.g._ RON).

Before:

```
module: (
    expressions: [
        Literal((
            value: Vector((
                vector_type: (
                    elem_type: Float,
                    count: 3,
                ),
                storage: (1067030938, 3227307213, 1118770935, 0),
            )),
        )),
        Literal((
            value: Vector((
                vector_type: (
                    elem_type: Bool,
                    count: 2,
                ),
                storage: (0, 4294967295, 0, 0),
            )),
        )),
        Binary(
            op: Add,
            left: (
                index: 2,
            ),
            right: (
                index: 1,
            ),
        ),
    ],
),
```

After:

```
module: [
    Literal(Vector(Vec3((1.2, -3.45, 87.54485)))),
    Literal(Vector(BVec2((false, true)))),
    Binary(
        op: Add,
        left: 2,
        right: 1,
    ),
]
```

CHANGELOG.md

@@ -27,6 +27,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Merged the `InitModifier` and `UpdateModifier` traits into the `Modifier` subtrait; see other changelog entries for details. This helps manage modifiers in a unified way, and generally simplifies writing and maintain modifiers compatible with both the init and update contexts.
 - `EffectAsset::init()` and `EffectAsset::update()` now take a `Modifier`-bound type, and validate its `ModifierContext` is compatible (and panics if not).
 - `EffectAsset::render()` now panics if the modifier is not compatible with the `ModifierContext::Render`. Note that this indicates a malformed render modifier, because all objects implementing `RenderModifier` must include `ModifierContext::Render` in their `Modifier::context()`.
+- Improved the serialization format to reduce verbosity, by making the following types `#[serde(transparent)]`: `ExprHandle`, `LiteralExpr`, `Module`.
 
 ### Removed
 

src/asset.rs

@@ -592,6 +592,8 @@ impl AssetLoader for EffectAssetLoader {
 
 #[cfg(test)]
 mod tests {
+    use ron::ser::PrettyConfig;
+
     use crate::*;
 
     use super::*;
@@ -734,15 +736,94 @@ mod tests {
 
     #[test]
     fn test_serde_ron() {
+        let w = ExprWriter::new();
+
+        let pos = w.lit(Vec3::new(1.2, -3.45, 87.54485));
+        let x = w.lit(BVec2::new(false, true));
+        let _ = x + pos.clone();
+        let mod_pos = SetAttributeModifier::new(Attribute::POSITION, pos.expr());
+
         let effect = EffectAsset {
             name: "Effect".into(),
             capacity: 4096,
             spawner: Spawner::rate(30.0.into()),
+            module: w.finish(),
             ..Default::default()
-        };
-
-        let s = ron::to_string(&effect).unwrap();
-        let _effect_serde: EffectAsset = ron::from_str(&s).unwrap();
-        // assert_eq!(effect, effect_serde);
+        }
+        .with_property("my_prop", Vec3::new(1.2, -2.3, 55.32).into())
+        .init(mod_pos);
+
+        let s = ron::ser::to_string_pretty(&effect, PrettyConfig::new().new_line("\n".to_string()))
+            .unwrap();
+        assert_eq!(
+            s,
+            r#"(
+    name: "Effect",
+    capacity: 4096,
+    spawner: (
+        num_particles: Single(30.0),
+        spawn_time: Single(1.0),
+        period: Single(1.0),
+        starts_active: true,
+        starts_immediately: true,
+    ),
+    z_layer_2d: 0.0,
+    simulation_space: Global,
+    simulation_condition: WhenVisible,
+    init_modifiers: [
+        {
+            "SetAttributeModifier": (
+                attribute: "position",
+                value: 1,
+            ),
+        },
+    ],
+    update_modifiers: [],
+    render_modifiers: [],
+    properties: [
+        (
+            name: "my_prop",
+            default_value: Vector(Vec3((1.2, -2.3, 55.32))),
+        ),
+    ],
+    motion_integration: PostUpdate,
+    module: [
+        Literal(Vector(Vec3((1.2, -3.45, 87.54485)))),
+        Literal(Vector(BVec2((false, true)))),
+        Binary(
+            op: Add,
+            left: 2,
+            right: 1,
+        ),
+    ],
+    alpha_mode: Blend,
+)"#
+        );
+        let effect_serde: EffectAsset = ron::from_str(&s).unwrap();
+        assert_eq!(effect.name, effect_serde.name);
+        assert_eq!(effect.capacity, effect_serde.capacity);
+        assert_eq!(effect.spawner, effect_serde.spawner);
+        assert_eq!(effect.z_layer_2d, effect_serde.z_layer_2d);
+        assert_eq!(effect.simulation_space, effect_serde.simulation_space);
+        assert_eq!(
+            effect.simulation_condition,
+            effect_serde.simulation_condition
+        );
+        assert_eq!(effect.properties, effect_serde.properties);
+        assert_eq!(effect.motion_integration, effect_serde.motion_integration);
+        assert_eq!(effect.module, effect_serde.module);
+        assert_eq!(effect.alpha_mode, effect_serde.alpha_mode);
+        assert_eq!(
+            effect.init_modifiers().count(),
+            effect_serde.init_modifiers().count()
+        );
+        assert_eq!(
+            effect.update_modifiers().count(),
+            effect_serde.update_modifiers().count()
+        );
+        assert_eq!(
+            effect.render_modifiers().count(),
+            effect_serde.render_modifiers().count()
+        );
     }
 }

src/graph/expr.rs

@@ -125,6 +125,7 @@ type Index = NonZeroU32;
     Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Reflect, Serialize, Deserialize,
 )]
 #[repr(transparent)]
+#[serde(transparent)]
 pub struct ExprHandle {
     index: Index,
 }
@@ -161,6 +162,7 @@ impl ExprHandle {
 /// [`lit()`]: Module::lit
 /// [`attr()`]: Module::attr
 #[derive(Debug, Default, Clone, PartialEq, Hash, Reflect, Serialize, Deserialize)]
+#[serde(transparent)]
 pub struct Module {
     expressions: Vec<Expr>,
 }
@@ -872,6 +874,7 @@ impl Expr {
 ///
 /// [`is_const()`]: LiteralExpr::is_const
 #[derive(Debug, Clone, Copy, PartialEq, Hash, Reflect, Serialize, Deserialize)]
+#[serde(transparent)]
 pub struct LiteralExpr {
     value: Value,
 }

src/graph/mod.rs

@@ -437,6 +437,7 @@ impl ElemType for u32 {
 
 /// Variant storage for a vector value.
 #[derive(Debug, Clone, Copy, Reflect, Serialize, Deserialize)]
+#[serde(from = "VectorValueEnum", into = "VectorValueEnum")]
 pub struct VectorValue {
     vector_type: VectorType,
     storage: [u32; 4],
@@ -1203,6 +1204,90 @@ impl From<Vec4> for VectorValue {
     }
 }
 
+/// Helper used as placeholder instead of [`VectorValue`] for serialization.
+///
+/// This enables serializing [`VectorValue`] as a glam type enum, instead of the
+/// compressed binary runtime representation actually stored inside
+/// [`VectorValue`].
+#[derive(Serialize, Deserialize)]
+enum VectorValueEnum {
+    BVec2(BVec2),
+    BVec3(BVec3),
+    BVec4(BVec4),
+    IVec2(IVec2),
+    IVec3(IVec3),
+    IVec4(IVec4),
+    UVec2(UVec2),
+    UVec3(UVec3),
+    UVec4(UVec4),
+    Vec2(Vec2),
+    Vec3(Vec3),
+    Vec4(Vec4),
+}
+
+impl From<VectorValueEnum> for VectorValue {
+    fn from(value: VectorValueEnum) -> Self {
+        match value {
+            VectorValueEnum::BVec2(v) => VectorValue::new_bvec2(v),
+            VectorValueEnum::BVec3(v) => VectorValue::new_bvec3(v),
+            VectorValueEnum::BVec4(v) => VectorValue::new_bvec4(v),
+            VectorValueEnum::IVec2(v) => VectorValue::new_ivec2(v),
+            VectorValueEnum::IVec3(v) => VectorValue::new_ivec3(v),
+            VectorValueEnum::IVec4(v) => VectorValue::new_ivec4(v),
+            VectorValueEnum::UVec2(v) => VectorValue::new_uvec2(v),
+            VectorValueEnum::UVec3(v) => VectorValue::new_uvec3(v),
+            VectorValueEnum::UVec4(v) => VectorValue::new_uvec4(v),
+            VectorValueEnum::Vec2(v) => VectorValue::new_vec2(v),
+            VectorValueEnum::Vec3(v) => VectorValue::new_vec3(v),
+            VectorValueEnum::Vec4(v) => VectorValue::new_vec4(v),
+        }
+    }
+}
+
+impl From<VectorValue> for VectorValueEnum {
+    fn from(value: VectorValue) -> Self {
+        let count = value.vector_type.count();
+        match value.elem_type() {
+            ScalarType::Bool => {
+                if count == 2 {
+                    VectorValueEnum::BVec2(value.as_bvec2())
+                } else if count == 3 {
+                    VectorValueEnum::BVec3(value.as_bvec3())
+                } else {
+                    VectorValueEnum::BVec4(value.as_bvec4())
+                }
+            }
+            ScalarType::Int => {
+                if count == 2 {
+                    VectorValueEnum::IVec2(value.as_ivec2())
+                } else if count == 3 {
+                    VectorValueEnum::IVec3(value.as_ivec3())
+                } else {
+                    VectorValueEnum::IVec4(value.as_ivec4())
+                }
+            }
+            ScalarType::Uint => {
+                if count == 2 {
+                    VectorValueEnum::UVec2(value.as_uvec2())
+                } else if count == 3 {
+                    VectorValueEnum::UVec3(value.as_uvec3())
+                } else {
+                    VectorValueEnum::UVec4(value.as_uvec4())
+                }
+            }
+            ScalarType::Float => {
+                if count == 2 {
+                    VectorValueEnum::Vec2(value.as_vec2())
+                } else if count == 3 {
+                    VectorValueEnum::Vec3(value.as_vec3())
+                } else {
+                    VectorValueEnum::Vec4(value.as_vec4())
+                }
+            }
+        }
+    }
+}
+
 /// Floating-point matrix value.
 #[derive(Debug, Clone, Copy, Reflect, Serialize, Deserialize)]
 pub struct MatrixValue {