This should avoid some unnecessary animation overhead

CHANGELOG.md

@@ -27,8 +27,10 @@
 - Pokémon can now have their Minecraft footstep sounds silenced in their poser. This doesn't affect emitting game events.
 - Fixed the Molang coalescing operator not working the way you'd expect a coalesce operator to. 
 - Added `v.spawnable_position` to the weight spawn rule component's "weight" expression
+- Added `is_alive` function to entities. Can be useful for terminating particles bound to them.
 
 ### Particles
+- Fixed local space settings for particles that are attached to Pokemon locators. Should fix a lot of jitters and rotation issues.
 
 ### Localization
 - Updated translations for:

common/src/main/kotlin/com/cobblemon/mod/common/api/molang/function/EntityMoLangFunctions.kt

@@ -266,6 +266,9 @@ object EntityMoLangFunctions : AbstractMoLangFunctionHolder<Entity>() {
             entity.noPhysics = intangible
             DoubleValue.ONE
         }
+        functions["is_alive"] = { params ->
+            if (entity.isAlive) DoubleValue.ONE else DoubleValue.ZERO
+        }
 
         when (entity) {
             is PosableEntity -> {

common/src/main/kotlin/com/cobblemon/mod/common/client/render/SnowstormParticle.kt

@@ -15,7 +15,9 @@ import com.cobblemon.mod.common.ModAPI
 import com.cobblemon.mod.common.api.snowstorm.ParticleMaterial
 import com.cobblemon.mod.common.api.snowstorm.ParticleMaterials
 import com.cobblemon.mod.common.api.snowstorm.UVDetails
+import com.cobblemon.mod.common.client.MountedPokemonAnimationRenderController
 import com.cobblemon.mod.common.client.particle.ParticleStorm
+import com.cobblemon.mod.common.entity.pokemon.PokemonEntity
 import com.cobblemon.mod.common.util.math.geometry.transformDirection
 import com.cobblemon.mod.common.util.resolveBoolean
 import com.cobblemon.mod.common.util.resolveDouble
@@ -140,6 +142,19 @@ class SnowstormParticle(
            }
         }
 
+        /* Without this, locators will lag behind the animation because particles render before Pokemon.
+         * This is important for particles attached to locators using local position/rotation.
+         *
+         * In the future, we may want to make `MountedPokemonAnimationRenderController` a more
+         * generic utility for bedrock models if we see a case where other non-pokemon models (ie. NPCs)
+         * should emit particles in their animations that utilise local space.
+         */
+        storm.entity?.let {
+            if (storm.effect.space.localPosition && it is PokemonEntity) {
+                MountedPokemonAnimationRenderController.setup(it, tickDelta)
+            }
+        }
+
         applyRandoms()
         setParticleAgeInRuntime()
         storm.effect.curves.forEach { it.apply(runtime) }
@@ -147,11 +162,16 @@ class SnowstormParticle(
 
         val vec3d = camera.position
 
+        // Interpolate because we are often between the ticks where these positions update.
         val interpLocalX = Mth.lerp(tickDelta.toDouble(), prevLocalX, localX)
         val interpLocalY = Mth.lerp(tickDelta.toDouble(), prevLocalY, localY)
         val interpLocalZ = Mth.lerp(tickDelta.toDouble(), prevLocalZ, localZ)
 
-        val pos = if (storm.effect.space.localRotation) {
+        val pos = if (storm.effect.space.localPosition && storm.effect.space.localRotation) {
+            val vec = Vec3(interpLocalX, interpLocalY, interpLocalZ)
+            val rotated = storm.attachedMatrix.matrix.transformDirection(vec)
+            Vector3d(rotated.x, rotated.y, rotated.z)
+        } else if (storm.effect.space.localRotation) {
             val interpRotation = Mth.lerp(tickDelta.toDouble(), 0.0, currentRotation.angle)
             val vec = Vector3d(interpLocalX, interpLocalY, interpLocalZ)
             oldAxisRotation.transform(vec)
@@ -160,9 +180,11 @@ class SnowstormParticle(
             Vector3d(interpLocalX, interpLocalY, interpLocalZ)
         }
 
-        val f = (pos.x + originPos.x - vec3d.x()).toFloat()
-        val g = (pos.y + originPos.y - vec3d.y()).toFloat()
-        val h = (pos.z + originPos.z - vec3d.z()).toFloat()
+        val origin = if (storm.effect.space.localPosition) storm.attachedMatrix.getOrigin() else originPos
+
+        val f = (pos.x + origin.x - vec3d.x()).toFloat()
+        val g = (pos.y + origin.y - vec3d.y()).toFloat()
+        val h = (pos.z + origin.z - vec3d.z()).toFloat()
         val quaternion = storm.effect.particle.cameraMode.getRotation(
             matrixWrapper = matrixWrapper,
             prevAngle = oRoll,
@@ -231,7 +253,7 @@ class SnowstormParticle(
 
     override fun tick() {
         if (storm.effect.space.localPosition) {
-            originPos = matrixWrapper.getOrigin()
+            originPos = storm.attachedMatrix.getOrigin()
         }
 
         applyRandoms()