GLDebugHelper.java

/*
 * Copyright (C) 2007 The Android Open Source Project
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */

package com.badlogic.gdx.backends.android.surfaceview;

import java.io.Writer;

import javax.microedition.khronos.egl.EGL;
import javax.microedition.khronos.opengles.GL;

/**
 * A helper class for debugging OpenGL ES applications.
 * 
 * Wraps the supplied GL interface with a new GL interface that adds support for error checking and logging.
 */
public class GLDebugHelper {

	/**
	 * Wrap an existing GL interface in a new GL interface that adds support for error checking and/or logging.
	 * <p>
	 * Wrapping means that the GL instance that is passed in to this method is wrapped inside a new GL instance that
	 * optionally performs additional operations before and after calling the wrapped GL instance.
	 * <p>
	 * Error checking means that the wrapper will automatically call glError after each GL operation, and throw a
	 * GLException if an error occurs. (By design, calling glError itself will not cause an exception to be thrown.)
	 * Enabling error checking is an alternative to manually calling glError after every GL operation.
	 * <p>
	 * Logging means writing a text representation of each GL method call to a log.
	 * <p>
	 * 
	 * @param gl
	 *            the existing GL interface. Must implement GL and GL10. May optionally implement GL11 as well.
	 * @param configFlags
	 *            A bitmask of error checking flags.
	 * @param log
	 *            - null to disable logging, non-null to enable logging.
	 * @return the wrapped GL instance.
	 */

	/** Check glError() after every call. */
	public static final int CONFIG_CHECK_GL_ERROR = (1 << 0);

	/** Check if all calls are on the same thread. */
	public static final int CONFIG_CHECK_THREAD = (1 << 1);

	/** Print argument names when logging GL Calls. */
	public static final int CONFIG_LOG_ARGUMENT_NAMES = (1 << 2);

	/**
	 * The Error number used in the GLException that is thrown if CONFIG_CHECK_THREAD is enabled and you call OpenGL ES
	 * on the a different thread.
	 */
	public static final int ERROR_WRONG_THREAD = 0x7000;

	public static GL wrap(GL gl, int configFlags, Writer log) {
		if (configFlags != 0) {
			gl = new GLErrorWrapper(gl, configFlags);
		}
		if (log != null) {
			boolean logArgumentNames = (CONFIG_LOG_ARGUMENT_NAMES & configFlags) != 0;
			gl = new GLLogWrapper(gl, log, logArgumentNames);
		}
		return gl;
	}

	/**
	 * Wrap an existing EGL interface in a new EGL interface that adds support for error checking and/or logging.
	 * 
	 * @param egl
	 *            the existing GL interface. Must implement EGL and EGL10. May optionally implement EGL11 as well.
	 * @param configFlags
	 *            A bitmask of error checking flags.
	 * @param log
	 *            - null to disable logging, non-null to enable logging.
	 * @return the wrapped EGL interface.
	 */
	public static EGL wrap(EGL egl, int configFlags, Writer log) {
		if (log != null) {
			egl = new EGLLogWrapper(egl, configFlags, log);
		}
		return egl;
	}
}