/*******************************************************************************
 * 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 com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.Pixmap;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.Texture.TextureFilter;
import com.badlogic.gdx.graphics.Texture.TextureWrap;

/** <p>
 * Encapsulates OpenGL ES 2.0 frame buffer objects. This is a simple helper class which should cover most FBO uses. It will
 * automatically create a texture for the color attachment and a renderbuffer for the depth buffer. You can get a hold of the
 * texture by {@link FrameBuffer#getColorBufferTexture()}. This class will only work with OpenGL ES 2.0.
 * </p>
 *
 * <p>
 * FrameBuffers are managed. In case of an OpenGL context loss, which only happens on Android when a user switches to another
 * application or receives an incoming call, the framebuffer will be automatically recreated.
 * </p>
 *
 * <p>
 * A FrameBuffer must be disposed if it is no longer needed
 * </p>
 *
 * @author mzechner, realitix */
public class FrameBuffer extends GLFrameBuffer<Texture> {

	/** Creates a new FrameBuffer having the given dimensions and potentially a depth buffer attached. */
	public FrameBuffer (Pixmap.Format format, int width, int height, boolean hasDepth) {
		this(format, width, height, hasDepth, false);
	}

	/** Creates a new FrameBuffer having the given dimensions and potentially a depth and a stencil buffer attached.
	 *
	 * @param format the format of the color buffer; according to the OpenGL ES 2.0 spec, only RGB565, RGBA4444 and RGB5_A1 are
	 *           color-renderable
	 * @param width the width of the framebuffer in pixels
	 * @param height the height of the framebuffer in pixels
	 * @param hasDepth whether to attach a depth buffer
	 * @throws com.badlogic.gdx.utils.GdxRuntimeException in case the FrameBuffer could not be created */
	public FrameBuffer (Pixmap.Format format, int width, int height, boolean hasDepth, boolean hasStencil) {
		super(format, width, height, hasDepth, hasStencil);
	}

	@Override
	protected Texture createColorTexture () {
		int glFormat = Pixmap.Format.toGlFormat(format);
		int glType = Pixmap.Format.toGlType(format);
		GLOnlyTextureData data = new GLOnlyTextureData(width, height, 0, glFormat, glFormat, glType);
		Texture result = new Texture(data);
		result.setFilter(TextureFilter.Linear, TextureFilter.Linear);
		result.setWrap(TextureWrap.ClampToEdge, TextureWrap.ClampToEdge);
		return result;
	}

	@Override
	protected void disposeColorTexture (Texture colorTexture) {
		colorTexture.dispose();
	}

	@Override
	protected void attachFrameBufferColorTexture () {
		Gdx.gl20.glFramebufferTexture2D(GL20.GL_FRAMEBUFFER, GL20.GL_COLOR_ATTACHMENT0, GL20.GL_TEXTURE_2D,
				colorTexture.getTextureObjectHandle(), 0);
	}

	/** See {@link GLFrameBuffer#unbind()} */
	public static void unbind () {
		GLFrameBuffer.unbind();
	}
}