can see camera working but not the actor gravity

src/net/torvald/gdx/backends/lwjgl/audio/Opus.kt

@@ -0,0 +1,17 @@
+package net.torvald.gdx.backends.lwjgl.audio
+
+import com.badlogic.gdx.backends.lwjgl.audio.OggInputStream
+import com.badlogic.gdx.backends.lwjgl.audio.OpenALAudio
+import com.badlogic.gdx.backends.lwjgl.audio.OpenALMusic
+import com.badlogic.gdx.backends.lwjgl.audio.OpenALSound
+import com.badlogic.gdx.files.FileHandle
+import com.badlogic.gdx.utils.StreamUtils
+import java.io.ByteArrayOutputStream
+
+/**
+ * Created by minjaesong on 2017-06-26.
+ */
+
+class Opus {
+
+}

src/net/torvald/gdx/backends/lwjgl/audio/OpusInputStream.java

@@ -0,0 +1,60 @@
+package net.torvald.gdx.backends.lwjgl.audio;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+/**
+ * Created by minjaesong on 2017-06-26.
+ */
+public class OpusInputStream extends InputStream {
+    public OpusInputStream() {
+        super();
+    }
+
+    @Override
+    public int read(@NotNull byte[] b) throws IOException {
+        return super.read(b);
+    }
+
+    @Override
+    public int read(@NotNull byte[] b, int off, int len) throws IOException {
+        return super.read(b, off, len);
+    }
+
+    @Override
+    public long skip(long n) throws IOException {
+        return super.skip(n);
+    }
+
+    @Override
+    public int available() throws IOException {
+        return super.available();
+    }
+
+    @Override
+    public void close() throws IOException {
+        super.close();
+    }
+
+    @Override
+    public synchronized void mark(int readlimit) {
+        super.mark(readlimit);
+    }
+
+    @Override
+    public synchronized void reset() throws IOException {
+        super.reset();
+    }
+
+    @Override
+    public boolean markSupported() {
+        return super.markSupported();
+    }
+
+    @Override
+    public int read() throws IOException {
+        return 0;
+    }
+}