Added OpenGL buffers cleanup

- Now OpenGL buffers are being cleaned when GL objects are disposed
- Fixed a bug when garbage collector ignore OpenGL objects

src/main/java/ru/windcorp/progressia/client/graphics/backend/LWJGLInitializer.java

@@ -83,6 +83,8 @@ class LWJGLInitializer {
 		glEnable(GL_DEPTH_TEST);
 		glEnable(GL_BLEND);
 		glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+
+		RenderTaskQueue.schedule(OpenGLObjectTracker::deleteEnqueuedObjects);
 	}
 
 	private static void setupWindowCallbacks() {

src/main/java/ru/windcorp/progressia/client/graphics/backend/OpenGLObjectTracker.java

@@ -17,29 +17,80 @@
  *******************************************************************************/
 package ru.windcorp.progressia.client.graphics.backend;
 
+import java.lang.ref.PhantomReference;
+import java.lang.ref.ReferenceQueue;
 import java.util.ArrayList;
 import java.util.Collection;
-
+import java.util.function.IntConsumer;
-/* 
- * FIXME deal with client invocations of .delete() when properly disposing of
- * objects mid-execution
- */
 
 public class OpenGLObjectTracker {
 
-	public static interface OpenGLDeletable {
+	public interface OpenGLDeletable {
-		void delete();
+		int getHandle();
 	}
 	
-	private static final Collection<OpenGLDeletable> TO_DELETE = new ArrayList<>();
+	private static final Collection<GLPhantomReference<OpenGLDeletable>> TO_DELETE = new ArrayList<>();
+	private static final ReferenceQueue<OpenGLDeletable> DELETE_QUEUE = new ReferenceQueue<>();
 	
-	public synchronized static void register(OpenGLDeletable object) {
+	public synchronized static void register(OpenGLDeletable object, IntConsumer glDeleter) {
-		TO_DELETE.add(object);
+		GLPhantomReference<OpenGLDeletable> glRef =
+				new GLPhantomReference<>(object, DELETE_QUEUE, object.getHandle(), glDeleter);
+		TO_DELETE.add(glRef);
 	}
 
-	public synchronized static void deleteAllObjects() {
+	public static void deleteAllObjects() {
-		TO_DELETE.forEach(OpenGLDeletable::delete);
+		for (GLPhantomReference<OpenGLDeletable> glRef
-		TO_DELETE.clear();
+				: TO_DELETE
+			 ) {
+			glRef.clear();
+		}
 	}
 
+	public static void deleteEnqueuedObjects() {
+		while (true) {
+			GLPhantomReference<?> glRef;
+			glRef = (GLPhantomReference<?>) DELETE_QUEUE.poll();
+			if (glRef == null) {
+				break;
+			} else {
+				glRef.delete();
+			}
+		}
+	}
+
+	private static class GLPhantomReference<T> extends PhantomReference<T> {
+
+		private final int referentGLhandle;
+		private final IntConsumer GLDeleter;
+
+		/**
+		 * Creates a new phantom reference that refers to the given object and
+		 * is registered with the given queue.
+		 *
+		 * <p> It is possible to create a phantom reference with a {@code null}
+		 * queue, but such a reference is completely useless: Its {@code get}
+		 * method will always return {@code null} and, since it does not have a queue,
+		 * it will never be enqueued.
+		 *
+		 * @param referent the object the new phantom reference will refer to
+		 * @param q        the queue with which the reference is to be registered,
+		 *                 or {@code null} if registration is not required
+		 */
+		public GLPhantomReference(T referent,
+								  ReferenceQueue<? super T> q,
+								  int referentGLhandle,
+								  IntConsumer GLDeleter) {
+			super(referent, q);
+			this.referentGLhandle = referentGLhandle;
+			this.GLDeleter = GLDeleter;
+		}
+
+		public int getHandle() {
+			return referentGLhandle;
+		}
+
+		public void delete() {
+			GLDeleter.accept(referentGLhandle);
+		}
+	}
 }

src/main/java/ru/windcorp/progressia/client/graphics/backend/VertexBufferObject.java

@@ -21,6 +21,7 @@ import static org.lwjgl.opengl.GL20.*;
 
 import java.nio.*;
 
+import org.lwjgl.opengl.GL20;
 import ru.windcorp.progressia.client.graphics.backend.OpenGLObjectTracker.OpenGLDeletable;
 
 public class VertexBufferObject implements OpenGLDeletable {
@@ -47,7 +48,7 @@ public class VertexBufferObject implements OpenGLDeletable {
 	
 	public VertexBufferObject(Usage usage) {
 		handle = glGenBuffers();
-		OpenGLObjectTracker.register(this);
+		OpenGLObjectTracker.register(this, GL20::glDeleteBuffers);
 
 		this.usage = usage;
 	}
@@ -194,10 +195,4 @@ public class VertexBufferObject implements OpenGLDeletable {
 	public int getHandle() {
 		return handle;
 	}
-
-	@Override
-	public void delete() {
-		glDeleteBuffers(handle);
-	}
-
 }

src/main/java/ru/windcorp/progressia/client/graphics/backend/shaders/Program.java

@@ -20,6 +20,7 @@ package ru.windcorp.progressia.client.graphics.backend.shaders;
 import static org.lwjgl.opengl.GL11.*;
 import static org.lwjgl.opengl.GL20.*;
 
+import org.lwjgl.opengl.GL20;
 import ru.windcorp.progressia.client.graphics.backend.OpenGLObjectTracker;
 import ru.windcorp.progressia.client.graphics.backend.OpenGLObjectTracker.OpenGLDeletable;
 import ru.windcorp.progressia.client.graphics.backend.shaders.attributes.Attribute;
@@ -32,7 +33,7 @@ public class Program implements OpenGLDeletable {
 
 	public Program(Shader vertexShader, Shader fragmentShader) {
 		handle = glCreateProgram();
-		OpenGLObjectTracker.register(this);
+		OpenGLObjectTracker.register(this, GL20::glDeleteProgram);
 
 		glAttachShader(handle, vertexShader.getHandle());
 		glAttachShader(handle, fragmentShader.getHandle());
@@ -57,8 +58,6 @@ public class Program implements OpenGLDeletable {
 	}
 
 	@Override
-	public void delete() {
+	public int getHandle() { return handle; }
-		glDeleteProgram(handle);
-	}
 
 }

src/main/java/ru/windcorp/progressia/client/graphics/backend/shaders/Shader.java

@@ -22,6 +22,7 @@ import static org.lwjgl.opengl.GL20.*;
 
 import java.util.Locale;
 
+import org.lwjgl.opengl.GL20;
 import ru.windcorp.progressia.client.graphics.backend.OpenGLObjectTracker;
 import ru.windcorp.progressia.client.graphics.backend.OpenGLObjectTracker.OpenGLDeletable;
 import ru.windcorp.progressia.common.resource.Resource;
@@ -69,7 +70,7 @@ public class Shader implements OpenGLDeletable {
 
 	public Shader(ShaderType type, String source) {
 		handle = glCreateShader(type.getGlCode());
-		OpenGLObjectTracker.register(this);
+		OpenGLObjectTracker.register(this, GL20::glDeleteShader);
 
 		this.type = type;
 
@@ -90,11 +91,6 @@ public class Shader implements OpenGLDeletable {
 		);
 	}
 
-	@Override
-	public void delete() {
-		glDeleteShader(handle);
-	}
-
 	public int getHandle() {
 		return handle;
 	}

src/main/java/ru/windcorp/progressia/client/graphics/texture/TexturePrimitive.java

@@ -22,6 +22,7 @@ import static org.lwjgl.opengl.GL20.*;
 
 import java.util.Arrays;
 
+import org.lwjgl.opengl.GL11;
 import ru.windcorp.progressia.client.graphics.backend.OpenGLObjectTracker;
 import ru.windcorp.progressia.client.graphics.backend.OpenGLObjectTracker.OpenGLDeletable;
 import ru.windcorp.progressia.common.util.crash.CrashReports;
@@ -87,7 +88,7 @@ public class TexturePrimitive implements OpenGLDeletable {
 		if (isLoaded()) return;
 		
 		handle = pixels.load();
-		OpenGLObjectTracker.register(this);
+		OpenGLObjectTracker.register(this, GL11::glDeleteTextures);
 
 		if (handle < 0) {
 			CrashReports.report(null, "Failed to allocate texture");
@@ -95,9 +96,7 @@ public class TexturePrimitive implements OpenGLDeletable {
 	}
 
 	@Override
-	public void delete() {
+	public int getHandle() {
-		if (isLoaded())
+		return handle;
-			glDeleteTextures(handle);
 	}
-
 }