Add API to force modified speed logic on carts

Other mods can use AudakiCartEngine.registerModifiedEngineCheck to
register a cart checker function. Return true to force modified speed
logic, false to force vanilla speed logic.

src/main/java/audaki/cart_engine/AudakiCartEngine.java

@@ -0,0 +1,22 @@
+package audaki.cart_engine;
+
+import net.fabricmc.api.ModInitializer;
+import net.minecraft.entity.vehicle.AbstractMinecartEntity;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.function.Function;
+
+public class AudakiCartEngine implements ModInitializer {
+ public static List<Function<AbstractMinecartEntity, Boolean>> CART_CHECK_MODIFIED_ENGINE = new ArrayList<>();
+
+ // Function should take one AbstractMinecartEntity. Return true to force
+ // modified speed logic, false to force vanilla speed logic, and null
+ // otherwise.
+ public static void registerModifiedEngineCheck(Function<AbstractMinecartEntity, Boolean> cartChecker) {
+ CART_CHECK_MODIFIED_ENGINE.add(cartChecker);
+ }
+
+ public void onInitialize() {
+ }
+}

src/main/java/audaki/cart_engine/mixin/AbstractMinecartEntityMixin.java

@@ -1,5 +1,6 @@
 package audaki.cart_engine.mixin;
 
+import audaki.cart_engine.AudakiCartEngine;
 import com.mojang.datafixers.util.Pair;
 import net.minecraft.block.AbstractRailBlock;
 import net.minecraft.block.BlockState;
@@ -28,6 +29,7 @@
 import java.util.List;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.function.BiFunction;
+import java.util.function.Function;
 import java.util.function.Supplier;
 
 @Mixin(AbstractMinecartEntity.class) // lower value, higher priority - apply first so other mods can still mixin
@@ -69,16 +71,34 @@ private static RailShape getRailShape(BlockState state) {
 
  @Inject(at = @At("HEAD"), method = "moveOnRail", cancellable = true)
  protected void moveOnRailOverwrite(BlockPos pos, BlockState state, CallbackInfo ci) {
+ // Loop through checks registered by other mods
+ Boolean shouldUseModifiedEngine = null;
+ for (Function<AbstractMinecartEntity, Boolean> cartChecker : AudakiCartEngine.CART_CHECK_MODIFIED_ENGINE) {
+ shouldUseModifiedEngine = cartChecker.apply((AbstractMinecartEntity) (Object) this);
+ // Check if the modified engine is required/suppressed
+ if (shouldUseModifiedEngine != null) {
+ break;
+ }
+ }
 
- // We only change logic for rideable minecarts so we don't break hopper/chest minecart creations
- if (this.getMinecartType() != Type.RIDEABLE) {
+ // Check if modified engine was suppressed
+ if (!shouldUseModifiedEngine) {
  return;
  }
 
- // We only change logic when the minecart is currently being ridden by a living entity (player/villager/mob)
- boolean hasLivingRider = this.getFirstPassenger() instanceof LivingEntity;
- if (!hasLivingRider) {
- return;
+ // If no mods required modified engine, we do our own logic here
+ if (shouldUseModifiedEngine == null) {
+
+ // We only change logic for rideable minecarts so we don't break hopper/chest minecart creations
+ if (this.getMinecartType() != Type.RIDEABLE) {
+ return;
+ }
+
+ // We only change logic when the minecart is currently being ridden by a living entity (player/villager/mob)
+ boolean hasLivingRider = this.getFirstPassenger() instanceof LivingEntity;
+ if (!hasLivingRider) {
+ return;
+ }
  }
 
  this.modifiedMoveOnRail(pos, state);

src/main/resources/fabric.mod.json

@@ -24,6 +24,11 @@
  "icon": "assets/audaki_cart_engine/icon.png",
 
  "environment": "*",
+ "entrypoints": {
+ "main": [
+ "audaki.cart_engine.AudakiCartEngine"
+ ]
+ },
  "mixins": [
  "audaki_cart_engine.mixins.json"
  ],