/*******************************************************************************
* 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.ByteBuffer;
import java.nio.ShortBuffer;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.utils.BufferUtils;
import com.badlogic.gdx.utils.GdxRuntimeException;
/** <p>
* In IndexBufferObject wraps OpenGL's index buffer functionality to be used in conjunction with VBOs. This class can be
* seamlessly used with OpenGL ES 1.x and 2.0.
* </p>
*
* <p>
* Uses indirect Buffers on Android 1.5/1.6 to fix GC invocation due to leaking PlatformAddress instances.
* </p>
*
* <p>
* You can also use this to store indices for vertex arrays. Do not call {@link #bind()} or {@link #unbind()} in this case but
* rather use {@link #getBuffer()} to use the buffer directly with glDrawElements. You must also create the IndexBufferObject with
* the second constructor and specify isDirect as true as glDrawElements in conjunction with vertex arrays needs direct buffers.
* </p>
*
* <p>
* VertexBufferObjects must be disposed via the {@link #dispose()} method when no longer needed
* </p>
*
* @author mzechner, Thorsten Schleinzer */
public class IndexBufferObject implements IndexData {
final ShortBuffer buffer;
final ByteBuffer byteBuffer;
int bufferHandle;
final boolean isDirect;
boolean isDirty = true;
boolean isBound = false;
final int usage;
// used to work around bug: https://android-review.googlesource.com/#/c/73175/
private final boolean empty;
/** Creates a new static IndexBufferObject to be used with vertex arrays.
*
* @param maxIndices the maximum number of indices this buffer can hold */
public IndexBufferObject (int maxIndices) {
this(true, maxIndices);
}
/** Creates a new IndexBufferObject.
*
* @param isStatic whether the index buffer is static
* @param maxIndices the maximum number of indices this buffer can hold */
public IndexBufferObject (boolean isStatic, int maxIndices) {
empty = maxIndices == 0;
if (empty) {
maxIndices = 1; // avoid allocating a zero-sized buffer because of bug in Android's ART < Android 5.0
}
byteBuffer = BufferUtils.newUnsafeByteBuffer(maxIndices * 2);
isDirect = true;
buffer = byteBuffer.asShortBuffer();
buffer.flip();
byteBuffer.flip();
bufferHandle = Gdx.gl20.glGenBuffer();
usage = isStatic ? GL20.GL_STATIC_DRAW : GL20.GL_DYNAMIC_DRAW;
}
/** @return the number of indices currently stored in this buffer */
public int getNumIndices () {
return empty ? 0 : buffer.limit();
}
/** @return the maximum number of indices this IndexBufferObject can store. */
public int getNumMaxIndices () {
return empty ? 0 : buffer.capacity();
}
/** <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 shorts to copy */
public void setIndices (short[] indices, int offset, int count) {
isDirty = true;
buffer.clear();
buffer.put(indices, offset, count);
buffer.flip();
byteBuffer.position(0);
byteBuffer.limit(count << 1);
if (isBound) {
Gdx.gl20.glBufferData(GL20.GL_ELEMENT_ARRAY_BUFFER, byteBuffer.limit(), byteBuffer, usage);
isDirty = false;
}
}
public void setIndices (ShortBuffer indices) {
isDirty = true;
int pos = indices.position();
buffer.clear();
buffer.put(indices);
buffer.flip();
indices.position(pos);
byteBuffer.position(0);
byteBuffer.limit(buffer.limit() << 1);
if (isBound) {
Gdx.gl20.glBufferData(GL20.GL_ELEMENT_ARRAY_BUFFER, byteBuffer.limit(), byteBuffer, usage);
isDirty = false;
}
}
@Override
public void updateIndices (int targetOffset, short[] indices, int offset, int count) {
isDirty = true;
final int pos = byteBuffer.position();
byteBuffer.position(targetOffset * 2);
BufferUtils.copy(indices, offset, byteBuffer, count);
byteBuffer.position(pos);
buffer.position(0);
if (isBound) {
Gdx.gl20.glBufferData(GL20.GL_ELEMENT_ARRAY_BUFFER, byteBuffer.limit(), byteBuffer, usage);
isDirty = false;
}
}
/** <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 () {
isDirty = true;
return buffer;
}
/** Binds this IndexBufferObject for rendering with glDrawElements. */
public void bind () {
if (bufferHandle == 0) throw new GdxRuntimeException("No buffer allocated!");
Gdx.gl20.glBindBuffer(GL20.GL_ELEMENT_ARRAY_BUFFER, bufferHandle);
if (isDirty) {
byteBuffer.limit(buffer.limit() * 2);
Gdx.gl20.glBufferData(GL20.GL_ELEMENT_ARRAY_BUFFER, byteBuffer.limit(), byteBuffer, usage);
isDirty = false;
}
isBound = true;
}
/** Unbinds this IndexBufferObject. */
public void unbind () {
Gdx.gl20.glBindBuffer(GL20.GL_ELEMENT_ARRAY_BUFFER, 0);
isBound = false;
}
/** Invalidates the IndexBufferObject so a new OpenGL buffer handle is created. Use this in case of a context loss. */
public void invalidate () {
bufferHandle = Gdx.gl20.glGenBuffer();
isDirty = true;
}
/** Disposes this IndexBufferObject and all its associated OpenGL resources. */
public void dispose () {
Gdx.gl20.glBindBuffer(GL20.GL_ELEMENT_ARRAY_BUFFER, 0);
Gdx.gl20.glDeleteBuffer(bufferHandle);
bufferHandle = 0;
BufferUtils.disposeUnsafeByteBuffer(byteBuffer);
}
}