Merge pull request jMonkeyEngine#1276 from MeFisto94/fix-gldebug

Fixes jMonkeyEngine#1272 - Improve GLDebugDesktop by reducing manual overrides

Author: MeFisto94

jme3-android/src/main/java/com/jme3/system/android/OGLESContext.java

@@ -52,13 +52,7 @@
 import com.jme3.input.dummy.DummyKeyInput;
 import com.jme3.input.dummy.DummyMouseInput;
 import com.jme3.renderer.android.AndroidGL;
-import com.jme3.renderer.opengl.GL;
-import com.jme3.renderer.opengl.GLES_30;
-import com.jme3.renderer.opengl.GLDebugES;
-import com.jme3.renderer.opengl.GLExt;
-import com.jme3.renderer.opengl.GLFbo;
-import com.jme3.renderer.opengl.GLRenderer;
-import com.jme3.renderer.opengl.GLTracer;
+import com.jme3.renderer.opengl.*;
 import com.jme3.system.*;
 import com.jme3.util.AndroidBufferAllocator;
 import com.jme3.util.BufferAllocatorFactory;
@@ -209,14 +203,14 @@ public void uncaughtException(Thread thread, Throwable thrown) {
         });
 
         timer = new NanoTimer();
-        Object gl = new AndroidGL();
+        GL gl = new AndroidGL();
         if (settings.getBoolean("GraphicsDebug")) {
-            gl = new GLDebugES((GL) gl, (GLExt) gl, (GLFbo) gl);
+            gl = (GL) GLDebug.createProxy(gl, gl, GL.class, GL2.class, GLES_30.class, GLFbo.class, GLExt.class);
         }
         if (settings.getBoolean("GraphicsTrace")) {
-            gl = GLTracer.createGlesTracer(gl, GL.class, GLES_30.class, GLFbo.class, GLExt.class);
+            gl = (GL)GLTracer.createGlesTracer(gl, GL.class, GLES_30.class, GLFbo.class, GLExt.class);
         }
-        renderer = new GLRenderer((GL)gl, (GLExt)gl, (GLFbo)gl);
+        renderer = new GLRenderer(gl, (GLExt)gl, (GLFbo)gl);
         renderer.initialize();
 
         JmeSystem.setSoftTextDialogInput(this);

jme3-core/src/main/java/com/jme3/renderer/opengl/GLDebug.java

@@ -1,11 +1,66 @@
+/*
+ * Copyright (c) 2009-2020 jMonkeyEngine
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * * Redistributions in binary form must reproduce the above copyright
+ *   notice, this list of conditions and the following disclaimer in the
+ *   documentation and/or other materials provided with the distribution.
+ *
+ * * Neither the name of 'jMonkeyEngine' nor the names of its contributors
+ *   may be used to endorse or promote products derived from this software
+ *   without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+ * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+ * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
 package com.jme3.renderer.opengl;
 
 import com.jme3.renderer.RendererException;
 
-public abstract class GLDebug {
+import java.lang.reflect.InvocationHandler;
+import java.lang.reflect.Method;
+import java.lang.reflect.Proxy;
 
+/**
+ * This class uses Reflection to intercept method calls to the Proxy Object ({@link #createProxy(GL, Object, Class[])}
+ * and extends them with the Error Checking in {@link #checkError()}.<br/>
+ * This means we don't have to generate a class with overrides for every possible method just to add a
+ * {@link #checkError()} call.<br/>
+ * Note that we should not call {@link #checkError()} for {@link GL#glGetError()}, it doesn't make sense.<br />
+ * Note that this class is general purpose and as such every class instance (every object) can be guarded as long as
+ * the passed gl instance is valid.<br/>
+ *
+ * @author MeFisto94
+ */
+public class GLDebug implements InvocationHandler {
+    protected Object obj;
     protected GL gl;
-    
+    protected Method methodGlGetError;
+
+    private GLDebug(GL gl, Object obj) throws NoSuchMethodException {
+        this.gl = gl;
+        this.obj = obj;
+        methodGlGetError = GL.class.getMethod("glGetError");
+        /* The NoSuchMethodException shouldn't be thrown, but since we're in a constructor and cannot fail safe
+         * otherwise, we throw it. */
+    }
+
     protected String decodeError(int err) {
         String errMsg;
         switch (err) {
@@ -46,4 +101,38 @@ protected void checkError() {
             throw new RendererException("An OpenGL error occurred - " + decodeError(err));
         }
     }
+
+    @Override
+    public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
+        Object result = method.invoke(obj, args);
+
+        if (method.equals(methodGlGetError)) {
+            return result;
+        }
+
+        checkError();
+        return result;
+    }
+
+    /**
+     * Creates a debug-proxied object, which will call {@link GL#glGetError()} after every method invocation and throw
+     * a {@link com.jme3.renderer.RendererException} if there was a GL Error.
+     *
+     * @param gl The GL Context, required to call {@link GL#glGetError()}
+     * @param obj The object which methods will be proxied
+     * @param implementedInterfaces The interfaces/class this object implements
+     * @return The Proxy object (or null if an error occured)
+     */
+    public static Object createProxy(GL gl, Object obj, Class<?>... implementedInterfaces) {
+        try {
+            return Proxy.newProxyInstance(
+                    GLDebug.class.getClassLoader(),
+                    implementedInterfaces,
+                    new GLDebug(gl, obj)
+            );
+        } catch (NoSuchMethodException nsme) {
+            throw new IllegalArgumentException ("Could not initialize the proxy because the glGetError method wasn't " +
+                    "found!", nsme);
+        }
+    }
 }