[ui] store Hud addition/removal tasks in order and process the queue …

…at the beginning of every frame while in a world (#213)

src/main/java/io/wispforest/owo/mixin/ui/MinecraftClientMixin.java

@@ -1,5 +1,6 @@
 package io.wispforest.owo.mixin.ui;
 
+import io.wispforest.owo.ui.event.ClientRenderCallback;
 import io.wispforest.owo.ui.event.WindowResizeCallback;
 import io.wispforest.owo.ui.util.DisposableScreen;
 import net.minecraft.client.MinecraftClient;
@@ -38,6 +39,16 @@ private void captureResize(CallbackInfo ci) {
         WindowResizeCallback.EVENT.invoker().onResized((MinecraftClient) (Object) this, this.window);
     }
 
+    @Inject(method = "render", at = @At(value = "INVOKE", target = "Lnet/minecraft/client/util/Window;setPhase(Ljava/lang/String;)V", ordinal = 1))
+    private void beforeRender(boolean tick, CallbackInfo ci) {
+        ClientRenderCallback.BEFORE.invoker().onRender((MinecraftClient) (Object) this);
+    }
+
+    @Inject(method = "render", at = @At(value = "INVOKE", target = "Lnet/minecraft/client/util/Window;swapBuffers()V", shift = At.Shift.AFTER))
+    private void afterRender(boolean tick, CallbackInfo ci) {
+        ClientRenderCallback.AFTER.invoker().onRender((MinecraftClient) (Object) this);
+    }
+
     @Inject(method = "setScreen", at = @At(value = "INVOKE", target = "Lnet/minecraft/client/gui/screen/Screen;removed()V"))
     private void captureSetScreen(Screen screen, CallbackInfo ci) {
         if (screen != null && this.currentScreen instanceof DisposableScreen disposable) {
@@ -64,5 +75,4 @@ private void captureSetScreen(Screen screen, CallbackInfo ci) {
             this.screensToDispose.clear();
         }
     }
-
 }

src/main/java/io/wispforest/owo/ui/event/ClientRenderCallback.java

@@ -0,0 +1,30 @@
+package io.wispforest.owo.ui.event;
+
+import net.fabricmc.fabric.api.event.Event;
+import net.fabricmc.fabric.api.event.EventFactory;
+import net.minecraft.client.MinecraftClient;
+
+public interface ClientRenderCallback {
+
+    /**
+     * Invoked just before the client's window enters the 'Render' phase, after the client
+     * has ticked and cleared the render task queue
+     */
+    Event<ClientRenderCallback> BEFORE = EventFactory.createArrayBacked(ClientRenderCallback.class, callbacks -> (client) -> {
+        for (var callback : callbacks) {
+            callback.onRender(client);
+        }
+    });
+
+    /**
+     * Called just after the client has finished rendering and drawing the
+     * current frame and swapped buffers
+     */
+    Event<ClientRenderCallback> AFTER = EventFactory.createArrayBacked(ClientRenderCallback.class, callbacks -> (client) -> {
+        for (var callback : callbacks) {
+            callback.onRender(client);
+        }
+    });
+
+    void onRender(MinecraftClient client);
+}

src/main/java/io/wispforest/owo/ui/hud/Hud.java

@@ -3,16 +3,16 @@
 import io.wispforest.owo.ui.container.FlowLayout;
 import io.wispforest.owo.ui.core.Component;
 import io.wispforest.owo.ui.core.OwoUIAdapter;
+import io.wispforest.owo.ui.event.ClientRenderCallback;
 import io.wispforest.owo.ui.event.WindowResizeCallback;
 import net.fabricmc.fabric.api.client.rendering.v1.HudRenderCallback;
+import net.fabricmc.fabric.api.resource.ResourceManagerHelper;
 import net.minecraft.client.MinecraftClient;
 import net.minecraft.util.Identifier;
 import org.jetbrains.annotations.Nullable;
 
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.Map;
-import java.util.Set;
+import java.util.*;
+import java.util.function.Consumer;
 import java.util.function.Supplier;
 
 /**
@@ -25,8 +25,7 @@ public class Hud {
     static boolean suppress = false;
 
     private static final Map<Identifier, Component> activeComponents = new HashMap<>();
-    private static final Map<Identifier, Supplier<Component>> pendingComponents = new HashMap<>();
-    private static final Set<Identifier> pendingRemovals = new HashSet<>();
+    private static final List<Consumer<FlowLayout>> pendingActions = new ArrayList<>();
 
     /**
      * Add a new component to be rendered on the in-game HUD.
@@ -40,7 +39,12 @@ public class Hud {
      *                  when the HUD is first rendered
      */
     public static void add(Identifier id, Supplier<Component> component) {
-        pendingComponents.put(id, component);
+        pendingActions.add(flowLayout -> {
+            var instance = component.get();
+
+            flowLayout.child(instance);
+            activeComponents.put(id, instance);
+        });
     }
 
     /**
@@ -49,7 +53,13 @@ public static void add(Identifier id, Supplier<Component> component) {
      * @param id The ID of the HUD component to remove
      */
     public static void remove(Identifier id) {
-        pendingRemovals.add(id);
+        pendingActions.add(flowLayout -> {
+            var component = activeComponents.get(id);
+            if (component == null) return;
+
+            flowLayout.removeChild(component);
+            activeComponents.remove(id);
+        });
     }
 
     /**
@@ -84,33 +94,18 @@ private static void initializeAdapter() {
             adapter.moveAndResize(0, 0, window.getScaledWidth(), window.getScaledHeight());
         });
 
-        HudRenderCallback.EVENT.register((context, tickDelta) -> {
-            if (suppress) return;
-
-            if (!pendingRemovals.isEmpty() && adapter != null) {
-                pendingRemovals.forEach(identifier -> {
-                    var component = activeComponents.get(identifier);
-                    if (component == null) return;
-
-                    adapter.rootComponent.removeChild(component);
-                    activeComponents.remove(identifier);
-                });
-                pendingRemovals.clear();
-            }
-
-            if (!pendingComponents.isEmpty()) {
+        ClientRenderCallback.BEFORE.register(client -> {
+            if (client.world == null) return;
+            if (!pendingActions.isEmpty()) {
                 if (adapter == null) initializeAdapter();
 
-                pendingComponents.forEach((identifier, componentSupplier) -> {
-                    var component = componentSupplier.get();
-
-                    adapter.rootComponent.child(component);
-                    activeComponents.put(identifier, component);
-                });
-                pendingComponents.clear();
+                pendingActions.forEach(action -> action.accept(adapter.rootComponent));
+                pendingActions.clear();
             }
+        });
 
-            if (adapter == null) return;
+        HudRenderCallback.EVENT.register((context, tickDelta) -> {
+            if (adapter == null || suppress) return;
 
             context.push().translate(0, 0, 100);
             adapter.render(context, -69, -69, tickDelta);