Pepper's catches

- GlCompat now a singleton, doesn't need to be re-created
 - Fix crash with F3 open and backend off
 - Clear program spec map before loading
 - Merge FlywheelClient and Flywheel classes

src/main/java/com/jozufozu/flywheel/Flywheel.java

@@ -4,15 +4,26 @@ import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.maven.artifact.versioning.ArtifactVersion;
 
+import com.jozufozu.flywheel.backend.Backend;
+import com.jozufozu.flywheel.backend.OptifineHandler;
 import com.jozufozu.flywheel.config.EngineArgument;
 import com.jozufozu.flywheel.config.FlwCommands;
 import com.jozufozu.flywheel.config.FlwConfig;
+import com.jozufozu.flywheel.core.Contexts;
+import com.jozufozu.flywheel.core.PartialModel;
+import com.jozufozu.flywheel.core.StitchedSprite;
+import com.jozufozu.flywheel.core.compile.ProgramCompiler;
+import com.jozufozu.flywheel.event.ReloadRenderersEvent;
+import com.jozufozu.flywheel.mixin.PausedPartialTickAccessor;
+import com.jozufozu.flywheel.vanilla.VanillaInstances;
 
 import net.minecraft.commands.synchronization.ArgumentTypes;
 import net.minecraft.commands.synchronization.EmptyArgumentSerializer;
 import net.minecraft.resources.ResourceLocation;
 import net.minecraftforge.api.distmarker.Dist;
 import net.minecraftforge.common.MinecraftForge;
+import net.minecraftforge.eventbus.api.IEventBus;
+import net.minecraftforge.fml.CrashReportCallables;
 import net.minecraftforge.fml.DistExecutor;
 import net.minecraftforge.fml.ModList;
 import net.minecraftforge.fml.common.Mod;
@@ -39,17 +50,43 @@ public class Flywheel {
 				.getModEventBus()
 				.addListener(this::setup);
 
-		MinecraftForge.EVENT_BUS.addListener(FlwCommands::onServerStarting);
-
 		FlwConfig.init();
 
-		DistExecutor.unsafeRunWhenOn(Dist.CLIENT, () -> FlywheelClient::clientInit);
+		DistExecutor.unsafeRunWhenOn(Dist.CLIENT, () -> Flywheel::clientInit);
 	}
 
 	public static ResourceLocation rl(String path) {
 		return new ResourceLocation(ID, path);
 	}
 
+	public static void clientInit() {
+		CrashReportCallables.registerCrashCallable("Flywheel Backend", Backend::getBackendDescriptor);
+
+		OptifineHandler.init();
+		Backend.init();
+		IEventBus modEventBus = FMLJavaModLoadingContext.get()
+				.getModEventBus();
+
+		modEventBus.addListener(Contexts::flwInit);
+		modEventBus.addListener(PartialModel::onModelRegistry);
+		modEventBus.addListener(PartialModel::onModelBake);
+		modEventBus.addListener(StitchedSprite::onTextureStitchPre);
+		modEventBus.addListener(StitchedSprite::onTextureStitchPost);
+
+		MinecraftForge.EVENT_BUS.addListener(FlwCommands::registerClientCommands);
+
+		MinecraftForge.EVENT_BUS.<ReloadRenderersEvent>addListener(ProgramCompiler::invalidateAll);
+
+		VanillaInstances.init();
+
+		// https://github.com/Jozufozu/Flywheel/issues/69
+		// Weird issue with accessor loading.
+		// Only thing I've seen that's close to a fix is to force the class to load before trying to use it.
+		// From the SpongePowered discord:
+		// https://discord.com/channels/142425412096491520/626802111455297538/675007581168599041
+		LOGGER.info("Successfully loaded {}", PausedPartialTickAccessor.class.getName());
+	}
+
 	private void setup(final FMLCommonSetupEvent event) {
 		ArgumentTypes.register(rl("engine").toString(), EngineArgument.class, new EmptyArgumentSerializer<>(EngineArgument::getInstance));
 	}

src/main/java/com/jozufozu/flywheel/FlywheelClient.java

@@ -1,45 +0,0 @@
-package com.jozufozu.flywheel;
-
-import com.jozufozu.flywheel.backend.Backend;
-import com.jozufozu.flywheel.backend.OptifineHandler;
-import com.jozufozu.flywheel.core.Contexts;
-import com.jozufozu.flywheel.core.PartialModel;
-import com.jozufozu.flywheel.core.StitchedSprite;
-import com.jozufozu.flywheel.core.compile.ProgramCompiler;
-import com.jozufozu.flywheel.event.ReloadRenderersEvent;
-import com.jozufozu.flywheel.mixin.PausedPartialTickAccessor;
-import com.jozufozu.flywheel.vanilla.VanillaInstances;
-
-import net.minecraftforge.common.MinecraftForge;
-import net.minecraftforge.eventbus.api.IEventBus;
-import net.minecraftforge.fml.CrashReportCallables;
-import net.minecraftforge.fml.javafmlmod.FMLJavaModLoadingContext;
-
-public class FlywheelClient {
-
-	public static void clientInit() {
-		CrashReportCallables.registerCrashCallable("Flywheel Backend", Backend::getBackendDescriptor);
-
-		OptifineHandler.init();
-		Backend.init();
-		IEventBus modEventBus = FMLJavaModLoadingContext.get()
-				.getModEventBus();
-
-		modEventBus.addListener(Contexts::flwInit);
-		modEventBus.addListener(PartialModel::onModelRegistry);
-		modEventBus.addListener(PartialModel::onModelBake);
-		modEventBus.addListener(StitchedSprite::onTextureStitchPre);
-		modEventBus.addListener(StitchedSprite::onTextureStitchPost);
-
-		MinecraftForge.EVENT_BUS.<ReloadRenderersEvent>addListener(ProgramCompiler::invalidateAll);
-
-		VanillaInstances.init();
-
-		// https://github.com/Jozufozu/Flywheel/issues/69
-		// Weird issue with accessor loading.
-		// Only thing I've seen that's close to a fix is to force the class to load before trying to use it.
-		// From the SpongePowered discord:
-		// https://discord.com/channels/142425412096491520/626802111455297538/675007581168599041
-		Flywheel.LOGGER.info("Successfully loaded {}", PausedPartialTickAccessor.class.getName());
-	}
-}

src/main/java/com/jozufozu/flywheel/backend/Backend.java

@@ -21,8 +21,6 @@ public class Backend {
 
 	private static FlwEngine engine;
 
-	public static GlCompat compat;
-
 	private static final Loader loader = new Loader();
 
 	public static FlwEngine getEngine() {
@@ -45,9 +43,7 @@ public class Backend {
 	public static void refresh() {
 		OptifineHandler.refresh();
 
-		compat = new GlCompat();
-
-		engine = chooseEngine(compat);
+		engine = chooseEngine();
 	}
 
 	public static boolean isOn() {
@@ -79,7 +75,7 @@ public class Backend {
 		RenderWork.enqueue(Minecraft.getInstance().levelRenderer::allChanged);
 	}
 
-	private static FlwEngine chooseEngine(GlCompat compat) {
+	private static FlwEngine chooseEngine() {
 		FlwEngine preferredChoice = FlwConfig.get()
 				.getEngine();
 
@@ -87,7 +83,7 @@ public class Backend {
 		boolean canUseEngine = switch (preferredChoice) {
 			case OFF -> true;
 			case BATCHING -> !usingShaders;
-			case INSTANCING -> !usingShaders && compat.instancedArraysSupported();
+			case INSTANCING -> !usingShaders && GlCompat.getInstance().instancedArraysSupported();
 		};
 
 		return canUseEngine ? preferredChoice : FlwEngine.OFF;

src/main/java/com/jozufozu/flywheel/backend/Loader.java

@@ -42,7 +42,7 @@ public class Loader implements ResourceManagerReloadListener {
 	public static final String PROGRAM_DIR = "flywheel/programs/";
 	private static final Gson GSON = new GsonBuilder().create();
 
-	private final Map<ResourceLocation, ProgramSpec> programSpecRegistry = new HashMap<>();
+	private final Map<ResourceLocation, ProgramSpec> programs = new HashMap<>();
 
 	private boolean firstLoad = true;
 
@@ -59,7 +59,7 @@ public class Loader implements ResourceManagerReloadListener {
 
 	@Nullable
 	public ProgramSpec get(ResourceLocation name) {
-		return programSpecRegistry.get(name);
+		return programs.get(name);
 	}
 
 	@Override
@@ -91,6 +91,8 @@ public class Loader implements ResourceManagerReloadListener {
 	}
 
 	private void loadProgramSpecs(ResourceManager manager) {
+		programs.clear();
+
 		Collection<ResourceLocation> programSpecs = manager.listResources(PROGRAM_DIR, s -> s.endsWith(".json"));
 
 		for (ResourceLocation location : programSpecs) {
@@ -109,21 +111,15 @@ public class Loader implements ResourceManagerReloadListener {
 
 				spec.setName(specName);
 
-				register(spec);
+				if (programs.containsKey(specName)) {
+					throw new IllegalStateException("Program spec '" + specName + "' already registered.");
+				}
+				programs.put(specName, spec);
+
 			} catch (Exception e) {
 				Backend.LOGGER.error(e);
 			}
 		}
 	}
 
-	/**
-	 * Register a shader program.
-	 */
-	private void register(ProgramSpec spec) {
-		ResourceLocation name = spec.name;
-		if (programSpecRegistry.containsKey(name)) {
-			throw new IllegalStateException("Program spec '" + name + "' already registered.");
-		}
-		programSpecRegistry.put(name, spec);
-	}
 }

src/main/java/com/jozufozu/flywheel/backend/gl/buffer/GlBuffer.java

@@ -4,8 +4,8 @@ import java.nio.ByteBuffer;
 
 import org.lwjgl.opengl.GL20;
 
-import com.jozufozu.flywheel.backend.Backend;
 import com.jozufozu.flywheel.backend.gl.GlObject;
+import com.jozufozu.flywheel.backend.gl.versioned.GlCompat;
 
 public abstract class GlBuffer extends GlObject {
 
@@ -21,7 +21,8 @@ public abstract class GlBuffer extends GlObject {
 	 * @return A buffer that will be persistent if the driver supports it.
 	 */
 	public static GlBuffer requestPersistent(GlBufferType type) {
-		if (Backend.compat.bufferStorageSupported()) {
+		if (GlCompat.getInstance()
+                .bufferStorageSupported()) {
 			return new PersistentGlBuffer(type);
 		} else {
 			return new MappedGlBuffer(type);

src/main/java/com/jozufozu/flywheel/backend/gl/buffer/PersistentGlBuffer.java

@@ -8,10 +8,10 @@ import java.nio.ByteBuffer;
 
 import org.lwjgl.opengl.GL30;
 
-import com.jozufozu.flywheel.backend.Backend;
 import com.jozufozu.flywheel.backend.gl.GlFence;
 import com.jozufozu.flywheel.backend.gl.error.GlError;
 import com.jozufozu.flywheel.backend.gl.error.GlException;
+import com.jozufozu.flywheel.backend.gl.versioned.GlCompat;
 
 public class PersistentGlBuffer extends GlBuffer implements Mappable {
 
@@ -46,7 +46,7 @@ public class PersistentGlBuffer extends GlBuffer implements Mappable {
 
 		fence.clear();
 
-		Backend.compat.bufferStorage.bufferStorage(type, size, flags);
+        GlCompat.getInstance().bufferStorage.bufferStorage(type, size, flags);
 
 		ByteBuffer byteBuffer = GL30.glMapBufferRange(type.glEnum, 0, size, flags);
 

src/main/java/com/jozufozu/flywheel/backend/gl/versioned/GlCompat.java

@@ -20,11 +20,20 @@ import net.minecraft.Util;
  */
 public class GlCompat {
 
+	private static GlCompat instance;
+
+	public static GlCompat getInstance() {
+		if (instance == null) {
+			instance = new GlCompat();
+		}
+		return instance;
+	}
+
 	public final InstancedArrays instancedArrays;
 	public final BufferStorage bufferStorage;
 	public final boolean amd;
 
-	public GlCompat() {
+	private GlCompat() {
 		GLCapabilities caps = GL.createCapabilities();
 		instancedArrays = getLatest(InstancedArrays.class, caps);
 		bufferStorage = getLatest(BufferStorage.class, caps);

src/main/java/com/jozufozu/flywheel/backend/instancing/InstanceWorld.java

@@ -1,8 +1,5 @@
 package com.jozufozu.flywheel.backend.instancing;
 
-import java.util.List;
-
-import com.jozufozu.flywheel.Flywheel;
 import com.jozufozu.flywheel.api.instance.DynamicInstance;
 import com.jozufozu.flywheel.api.instance.TickableInstance;
 import com.jozufozu.flywheel.backend.Backend;
@@ -137,10 +134,4 @@ public class InstanceWorld {
 				.forEach(entityInstanceManager::add);
 	}
 
-	public void getDebugString(List<String> debug) {
-		debug.add("");
-		debug.add("Flywheel: " + Flywheel.VERSION);
-		debug.add("B: " + blockEntityInstanceManager.getObjectCount() + ", E: " + entityInstanceManager.getObjectCount());
-		engine.addDebugInfo(debug);
-	}
 }

src/main/java/com/jozufozu/flywheel/backend/instancing/InstancedRenderDispatcher.java

@@ -2,6 +2,7 @@ package com.jozufozu.flywheel.backend.instancing;
 
 import java.util.List;
 
+import com.jozufozu.flywheel.Flywheel;
 import com.jozufozu.flywheel.backend.Backend;
 import com.jozufozu.flywheel.event.BeginFrameEvent;
 import com.jozufozu.flywheel.event.ReloadRenderersEvent;
@@ -116,7 +117,16 @@ public class InstancedRenderDispatcher {
 	}
 
 	public static void getDebugString(List<String> debug) {
-		instanceWorlds.get(Minecraft.getInstance().level)
-				.getDebugString(debug);
+		debug.add("");
+		debug.add("Flywheel: " + Flywheel.VERSION);
+
+		if (Backend.isOn()) {
+			InstanceWorld instanceWorld = instanceWorlds.get(Minecraft.getInstance().level);
+
+			debug.add("B: " + instanceWorld.blockEntityInstanceManager.getObjectCount() + ", E: " + instanceWorld.entityInstanceManager.getObjectCount());
+			instanceWorld.engine.addDebugInfo(debug);
+		} else {
+			debug.add("Disabled");
+		}
 	}
 }

src/main/java/com/jozufozu/flywheel/backend/instancing/instancing/GPUInstancer.java

@@ -6,11 +6,11 @@ import com.jozufozu.flywheel.Flywheel;
 import com.jozufozu.flywheel.api.InstanceData;
 import com.jozufozu.flywheel.api.struct.Instanced;
 import com.jozufozu.flywheel.api.struct.StructWriter;
-import com.jozufozu.flywheel.backend.Backend;
 import com.jozufozu.flywheel.backend.gl.GlVertexArray;
 import com.jozufozu.flywheel.backend.gl.buffer.GlBuffer;
 import com.jozufozu.flywheel.backend.gl.buffer.GlBufferType;
 import com.jozufozu.flywheel.backend.gl.buffer.MappedBuffer;
+import com.jozufozu.flywheel.backend.gl.versioned.GlCompat;
 import com.jozufozu.flywheel.backend.instancing.AbstractInstancer;
 import com.jozufozu.flywheel.backend.model.BufferedModel;
 import com.jozufozu.flywheel.backend.model.ModelAllocator;
@@ -198,7 +198,7 @@ public class GPUInstancer<D extends InstanceData> extends AbstractInstancer<D> {
 		vao.bindAttributes(attributeBaseIndex, instanceFormat);
 
 		for (int i = 0; i < instanceFormat.getAttributeCount(); i++) {
-			Backend.compat.instancedArrays.vertexAttribDivisor(attributeBaseIndex + i, 1);
+            GlCompat.getInstance().instancedArrays.vertexAttribDivisor(attributeBaseIndex + i, 1);
 		}
 	}
 }

src/main/java/com/jozufozu/flywheel/backend/instancing/instancing/InstancedMaterialGroup.java

@@ -7,8 +7,8 @@ import com.jozufozu.flywheel.api.InstanceData;
 import com.jozufozu.flywheel.api.MaterialGroup;
 import com.jozufozu.flywheel.api.struct.Instanced;
 import com.jozufozu.flywheel.api.struct.StructType;
-import com.jozufozu.flywheel.backend.Backend;
 import com.jozufozu.flywheel.backend.RenderLayer;
+import com.jozufozu.flywheel.backend.gl.versioned.GlCompat;
 import com.jozufozu.flywheel.backend.model.FallbackAllocator;
 import com.jozufozu.flywheel.backend.model.ModelAllocator;
 import com.jozufozu.flywheel.backend.model.ModelPool;
@@ -40,7 +40,8 @@ public class InstancedMaterialGroup<P extends WorldProgram> implements MaterialG
 	public InstancedMaterialGroup(InstancingEngine<P> owner, RenderType type) {
 		this.owner = owner;
 		this.type = type;
-		if (Backend.compat.onAMDWindows()) {
+        if (GlCompat.getInstance()
+                .onAMDWindows()) {
 			this.allocator = FallbackAllocator.INSTANCE;
 		} else {
 			this.allocator = new ModelPool(Formats.POS_TEX_NORMAL, 2048);

src/main/java/com/jozufozu/flywheel/config/FlwCommands.java

@@ -9,7 +9,7 @@ import net.minecraft.commands.Commands;
 import net.minecraftforge.client.event.RegisterClientCommandsEvent;
 
 public class FlwCommands {
-	public static void onServerStarting(RegisterClientCommandsEvent event) {
+	public static void registerClientCommands(RegisterClientCommandsEvent event) {
 		CommandDispatcher<CommandSourceStack> dispatcher = event.getDispatcher();
 
 		dispatcher.register(Commands.literal("flywheel")