RenderTarget.java

/**
 * Copyright 2008 - 2015 The Loon Game Engine Authors
 * 
 * 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.
 * 
 * @project loon
 * @author cping
 * @email：javachenpeng@yahoo.com
 * @version 0.5
 */
package loon.opengl;

import static loon.opengl.GL20.*;
import loon.Graphics;
import loon.LRelease;
import loon.LSystem;
import loon.LTexture;

public abstract class RenderTarget implements LRelease {

	public static RenderTarget create(Graphics gfx, final LTexture tex) {
		GL20 gl = gfx.gl;
		final int fb = gl.glGenFramebuffer();
		if (fb == 0){
			throw LSystem.runThrow("Failed to gen framebuffer: "
					+ gl.glGetError());
		}
		gl.glBindFramebuffer(GL_FRAMEBUFFER, fb);
		gl.glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
				GL_TEXTURE_2D, tex.getID(), 0);
		gl.checkError("RenderTarget.create");
		return new RenderTarget(gfx) {
			public int id() {
				return fb;
			}

			public int width() {
				return tex.pixelWidth();
			}

			public int height() {
				return tex.pixelHeight();
			}

			public float xscale() {
				return tex.pixelWidth() / tex.width();
			}

			public float yscale() {
				return tex.pixelHeight() / tex.height();
			}

			public boolean flip() {
				return false;
			}
		};
	}

	public final Graphics gfx;

	public RenderTarget(Graphics gfx) {
		this.gfx = gfx;
	}

	public abstract int id();

	public abstract int width();

	public abstract int height();

	public abstract float xscale();

	public abstract float yscale();

	public abstract boolean flip();

	public void bind() {
		gfx.gl.glBindFramebuffer(GL_FRAMEBUFFER, id());
		gfx.gl.glViewport(0, 0, width(), height());
	}

	@Override
	public void close() {
		if (!disposed) {
			disposed = true;
			gfx.gl.glDeleteFramebuffer(id());
		}
	}

	@Override
	public String toString() {
		return "[id=" + id() + ", size=" + width() + "x" + height() + " @ "
				+ xscale() + "x" + yscale() + ", flip=" + flip() + "]";
	}

	@Override
	protected void finalize() {
		if (!disposed){
			gfx.queueForDispose(this);
		}
	}

	private boolean disposed;
}