Fix title screen screenshot in automated client test (FabricMC#4177)

* Fix title screen screenshot

* Use accessor to detect when background fade is done

fabric-api-base/src/testmodClient/java/net/fabricmc/fabric/test/base/client/FabricApiAutoTestClient.java

@@ -27,13 +27,15 @@
 import static net.fabricmc.fabric.test.base.client.FabricClientTestHelper.takeScreenshot;
 import static net.fabricmc.fabric.test.base.client.FabricClientTestHelper.waitForLoadingComplete;
 import static net.fabricmc.fabric.test.base.client.FabricClientTestHelper.waitForScreen;
+import static net.fabricmc.fabric.test.base.client.FabricClientTestHelper.waitForTitleScreenFade;
 import static net.fabricmc.fabric.test.base.client.FabricClientTestHelper.waitForWorldTicks;
 
 import java.io.IOException;
 import java.io.UncheckedIOException;
 import java.nio.file.DirectoryStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.time.Duration;
 
 import com.mojang.authlib.GameProfile;
 import org.spongepowered.asm.mixin.MixinEnvironment;
@@ -83,7 +85,8 @@ private void runTest() {
 
 		{
 			waitForScreen(TitleScreen.class);
-			takeScreenshot("title_screen");
+			waitForTitleScreenFade();
+			takeScreenshot("title_screen", Duration.ZERO);
 			clickScreenButton("menu.singleplayer");
 		}
 

fabric-api-base/src/testmodClient/java/net/fabricmc/fabric/test/base/client/FabricClientTestHelper.java

@@ -27,6 +27,7 @@
 import net.minecraft.client.gui.Drawable;
 import net.minecraft.client.gui.screen.GameMenuScreen;
 import net.minecraft.client.gui.screen.Screen;
+import net.minecraft.client.gui.screen.TitleScreen;
 import net.minecraft.client.gui.screen.ingame.CreativeInventoryScreen;
 import net.minecraft.client.gui.screen.ingame.InventoryScreen;
 import net.minecraft.client.gui.screen.multiplayer.ConnectScreen;
@@ -44,6 +45,7 @@
 
 import net.fabricmc.fabric.test.base.client.mixin.CyclingButtonWidgetAccessor;
 import net.fabricmc.fabric.test.base.client.mixin.ScreenAccessor;
+import net.fabricmc.fabric.test.base.client.mixin.TitleScreenAccessor;
 import net.fabricmc.loader.api.FabricLoader;
 
 // Provides thread safe utils for interacting with a running game.
@@ -80,8 +82,12 @@ private static void setScreen(Function<MinecraftClient, Screen> screenSupplier)
 	}
 
 	public static void takeScreenshot(String name) {
+		takeScreenshot(name, Duration.ofSeconds(1));
+	}
+
+	public static void takeScreenshot(String name, Duration delay) {
 		// Allow time for any screens to open
-		waitFor(Duration.ofSeconds(1));
+		waitFor(delay);
 
 		submitAndWait(client -> {
 			ScreenshotRecorder.saveScreenshot(FabricLoader.getInstance().getGameDir().toFile(), name + ".png", client.getFramebuffer(), (message) -> {
@@ -166,6 +172,16 @@ public static void connectToServer(TestDedicatedServer server) {
 		});
 	}
 
+	public static void waitForTitleScreenFade() {
+		waitFor("Title screen fade", client -> {
+			if (!(client.currentScreen instanceof TitleScreen titleScreen)) {
+				return false;
+			}
+
+			return !((TitleScreenAccessor) titleScreen).getDoBackgroundFade();
+		});
+	}
+
 	private static void waitFor(String what, Predicate<MinecraftClient> predicate) {
 		waitFor(what, predicate, Duration.ofSeconds(10));
 	}

fabric-api-base/src/testmodClient/java/net/fabricmc/fabric/test/base/client/mixin/TitleScreenAccessor.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2016, 2017, 2018, 2019 FabricMC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package net.fabricmc.fabric.test.base.client.mixin;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.gen.Accessor;
+
+import net.minecraft.client.gui.screen.TitleScreen;
+
+@Mixin(TitleScreen.class)
+public interface TitleScreenAccessor {
+	@Accessor
+	boolean getDoBackgroundFade();
+}

fabric-api-base/src/testmodClient/resources/fabric-api-base-testmod.client.mixins.json

@@ -5,7 +5,8 @@
   "client": [
     "CyclingButtonWidgetAccessor",
     "MinecraftDedicatedServerMixin",
-    "ScreenAccessor"
+    "ScreenAccessor",
+    "TitleScreenAccessor"
   ],
   "injectors": {
     "defaultRequire": 1