Allow for pony data to be loaded from off-thread processes

src/main/java/com/minelittlepony/client/pony/Memoize.java

@@ -0,0 +1,43 @@
+package com.minelittlepony.client.pony;
+
+import java.util.function.Consumer;
+
+public interface Memoize<T> {
+    T get();
+
+    default T get(T fallback) {
+        T value = get();
+        return value == null ? fallback : value;
+    }
+
+    default boolean isPresent() {
+        return true;
+    }
+
+    static <T> Memoize<T> of(T value) {
+        return () -> value;
+    }
+
+    static <T> Memoize<T> load(Consumer<Consumer<T>> factory) {
+        return new Memoize<>() {
+            T value;
+            boolean loadRequested;
+            @Override
+            public T get() {
+                synchronized (this) {
+                    if (!loadRequested) {
+                        loadRequested = true;
+                        factory.accept(value -> {
+                            this.value = value;
+                        });
+                    }
+                }
+                return value;
+            }
+            @Override
+            public boolean isPresent() {
+                return value != null;
+            }
+        };
+    }
+}

src/main/java/com/minelittlepony/client/pony/Pony.java

@@ -37,11 +37,11 @@ import org.jetbrains.annotations.Unmodifiable;
 public class Pony implements IPony {
 
     private final Identifier texture;
-    private final IPonyData metadata;
+    private final Memoize<IPonyData> metadata;
 
     private boolean defaulted = false;
 
-    Pony(Identifier resource, IPonyData data) {
+    Pony(Identifier resource, Memoize<IPonyData> data) {
         texture = resource;
         metadata = data;
     }
@@ -62,16 +62,20 @@ public class Pony implements IPony {
 
     @Override
     public void updateForEntity(Entity entity) {
+        if (!metadata.isPresent()) {
+            return;
+        }
+
         if (entity instanceof RegistrationHandler && ((RegistrationHandler)entity).shouldUpdateRegistration(this)) {
             entity.calculateDimensions();
 
             PlayerEntity clientPlayer = MinecraftClient.getInstance().player;
             if (clientPlayer != null) {
                 if (Objects.equals(entity, clientPlayer) || Objects.equals(((PlayerEntity)entity).getGameProfile(), clientPlayer.getGameProfile())) {
-                    Channel.broadcastPonyData(new MsgPonyData(metadata, defaulted));
+                    Channel.broadcastPonyData(new MsgPonyData(getMetadata(), defaulted));
                 }
             }
-            PonyDataCallback.EVENT.invoker().onPonyDataAvailable((PlayerEntity)entity, metadata, defaulted, EnvType.CLIENT);
+            PonyDataCallback.EVENT.invoker().onPonyDataAvailable((PlayerEntity)entity, getMetadata(), defaulted, EnvType.CLIENT);
         }
     }
 
@@ -144,7 +148,7 @@ public class Pony implements IPony {
     }
 
     protected Vec3d getVisualEyePosition(LivingEntity entity) {
-        Size size = entity.isBaby() ? Sizes.FOAL : metadata.getSize();
+        Size size = entity.isBaby() ? Sizes.FOAL : getMetadata().getSize();
 
         return new Vec3d(
                 entity.getX(),
@@ -155,7 +159,7 @@ public class Pony implements IPony {
 
     @Override
     public Race getRace(boolean ignorePony) {
-        return getEffectiveRace(metadata.getRace(), ignorePony);
+        return getEffectiveRace(getMetadata().getRace(), ignorePony);
     }
 
     @Override
@@ -165,15 +169,12 @@ public class Pony implements IPony {
 
     @Override
     public IPonyData getMetadata() {
-        return metadata;
+        return metadata.get(PonyData.NULL);
     }
 
     @Override
     public boolean isSitting(LivingEntity entity) {
-        return entity.hasVehicle()/*
+        return entity.hasVehicle();
-                || (entity instanceof PlayerEntity
-                        && entity.getVelocity().x == 0 && entity.getVelocity().z == 0
-                        && !entity.isInsideWaterOrBubbleColumn() && entity.onGround && isCrouching(entity))*/;
     }
 
     @Override

src/main/java/com/minelittlepony/client/pony/PonyData.java

@@ -34,21 +34,22 @@ public class PonyData implements IPonyData {
     private static final PonyDataSerialiser SERIALISER = new PonyDataSerialiser();
 
     public static final IPonyData NULL = new PonyData(Race.HUMAN);
+    public static final Memoize<IPonyData> MEM_NULL = Memoize.of(NULL);
 
     /**
      * Parses the given resource into a new IPonyData.
      * This may either come from an attached json file or the image itself.
      */
-    public static IPonyData parse(@Nullable Identifier identifier) {
+    public static Memoize<IPonyData> parse(@Nullable Identifier identifier) {
         if (identifier == null) {
-            return NULL;
+            return MEM_NULL;
         }
 
         try (Resource res = MinecraftClient.getInstance().getResourceManager().getResource(identifier)) {
             PonyData data = res.getMetadata(SERIALISER);
 
             if (data != null) {
-                return data;
+                return Memoize.of(data);
             }
         } catch (FileNotFoundException e) {
             // Ignore uploaded texture
@@ -56,12 +57,14 @@ public class PonyData implements IPonyData {
             MineLittlePony.logger.warn("Unable to read {} metadata", identifier, e);
         }
 
-        try {
+        return Memoize.load(callback -> {
-            return NativeUtil.parseImage(identifier, NativePonyData::new);
+            NativeUtil.parseImage(identifier, img -> {
-        } catch (IllegalStateException e) {
+                callback.accept(new NativePonyData(img));
+            }, e -> {
                 MineLittlePony.logger.fatal("Unable to read {} metadata", identifier, e);
-            return NULL;
+                callback.accept(NULL);
-        }
+            });
+        });
     }
 
     @Expose

src/main/java/com/minelittlepony/client/pony/PonyManager.java

@@ -49,7 +49,7 @@ public class PonyManager implements IPonyManager, IdentifiableResourceReloadList
         try {
             return poniesCache.get(resource);
         } catch (ExecutionException e) {
-            return new Pony(resource, PonyData.NULL);
+            return new Pony(resource, Memoize.of(PonyData.NULL));
         }
     }
 

src/main/java/com/minelittlepony/client/util/render/NativeUtil.java

@@ -9,7 +9,7 @@ import com.mojang.blaze3d.systems.RenderSystem;
 
 import java.util.HashMap;
 import java.util.Map;
-import java.util.function.Function;
+import java.util.function.Consumer;
 
 import static com.mojang.blaze3d.platform.GlStateManager._getTexLevelParameter;
 import static org.lwjgl.opengl.GL11.*;
@@ -91,14 +91,16 @@ public class NativeUtil {
         }
     }
 
-    public static <T> T parseImage(Identifier resource, Function<NativeImage, T> consumer) {
+    public static void parseImage(Identifier resource, Consumer<NativeImage> consumer, Consumer<Exception> fail) {
+        try {
+            if (!RenderSystem.isOnRenderThread()) {
+                RenderSystem.recordRenderCall(() -> parseImage(resource, consumer, fail));
+                return;
+            }
+
             MinecraftClient mc = MinecraftClient.getInstance();
             TextureManager textures = mc.getTextureManager();
 
-        if (!RenderSystem.isOnRenderThread()) {
-            throw new IllegalStateException("This can only be called from the main thread.");
-        }
-
             // recreate NativeImage from the GL matrix
             textures.bindTexture(resource);
 
@@ -117,8 +119,10 @@ public class NativeUtil {
                 // This allocates a new array to store the image every time.
                 // Don't do this every time. Keep a cache and store it so we don't destroy memory.
                 image.loadFromTextureImage(0, false);
-
+                consumer.accept(image);
-            return consumer.apply(image);
+            }
+        } catch (Exception e) {
+            fail.accept(e);
         }
     }
 }