libGDX 1.9.7, fix #434

vtm-web/src/org/oscim/gdx/emu/com/badlogic/gdx/backends/gwt/GwtGraphics.java

@@ -143,6 +143,27 @@ public class GwtGraphics implements Graphics {
         return gl;
     }
 
+    @Override
+    public void setGL20(GL20 gl20) {
+        this.gl = gl20;
+        Gdx.gl = gl20;
+        Gdx.gl20 = gl20;
+    }
+
+    @Override
+    public boolean isGL30Available() {
+        return false;
+    }
+
+    @Override
+    public GL30 getGL30() {
+        return null;
+    }
+
+    @Override
+    public void setGL30(GL30 gl30) {
+    }
+
     @Override
     public int getWidth() {
         return canvas.getWidth();
@@ -524,16 +545,6 @@ public class GwtGraphics implements Graphics {
         return isFullscreenJSNI();
     }
 
-    @Override
-    public boolean isGL30Available() {
-        return false;
-    }
-
-    @Override
-    public GL30 getGL30() {
-        return null;
-    }
-
     @Override
     public Cursor newCursor(Pixmap pixmap, int xHotspot, int yHotspot) {
         return new GwtCursor(pixmap, xHotspot, yHotspot);