IndexData.java

/*******************************************************************************
 * Copyright 2011 See AUTHORS file.
 * 
 * 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.graphics.glutils;

import java.nio.ShortBuffer;

import com.badlogic.gdx.utils.Disposable;

/**
 * An IndexData instance holds index data. Can be either a plain short buffer or an OpenGL buffer object.
 * 
 * @author mzechner
 */
public interface IndexData extends Disposable {
	/** @return the number of indices currently stored in this buffer */
	public int getNumIndices();

	/** @return the maximum number of indices this IndexBufferObject can store. */
	public int getNumMaxIndices();

	/**
	 * <p>
	 * Sets the indices of this IndexBufferObject, discarding the old indices. The count must equal the number of
	 * indices to be copied to this IndexBufferObject.
	 * </p>
	 * 
	 * <p>
	 * This can be called in between calls to {@link #bind()} and {@link #unbind()}. The index data will be updated
	 * instantly.
	 * </p>
	 * 
	 * @param indices
	 *            the vertex data
	 * @param offset
	 *            the offset to start copying the data from
	 * @param count
	 *            the number of floats to copy
	 */
	public void setIndices(short[] indices, int offset, int count);

	/**
	 * <p>
	 * Returns the underlying ShortBuffer. If you modify the buffer contents they wil be uploaded on the call to
	 * {@link #bind()}. If you need immediate uploading use {@link #setIndices(short[], int, int)}.
	 * </p>
	 * 
	 * @return the underlying short buffer.
	 */
	public ShortBuffer getBuffer();

	/** Binds this IndexBufferObject for rendering with glDrawElements. */
	public void bind();

	/** Unbinds this IndexBufferObject. */
	public void unbind();

	/** Invalidates the IndexBufferObject so a new OpenGL buffer handle is created. Use this in case of a context loss. */
	public void invalidate();

	/** Disposes this IndexDatat and all its associated OpenGL resources. */
	public void dispose();
}