package graphics;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.nio.IntBuffer;

import org.lwjgl.opengl.Display;
import org.lwjgl.opengl.EXTFramebufferObject;
import org.lwjgl.opengl.GL11;
import org.lwjgl.opengl.GLContext;
import org.newdawn.slick.opengl.InternalTextureLoader;
import org.newdawn.slick.opengl.Texture;

public class OffscreenTexture
{
	private int myFBOId;
	private int m_iWidth;
	private int m_iHeight;
	private Texture m_texture;
	//private int m_iTextureID;
	private boolean drawn;
	
	public OffscreenTexture(int width, int height)
	{
		drawn = false;
		m_iWidth = width;
		m_iHeight = height;
		CreateTexture();
		boolean FBOEnabled = GLContext.getCapabilities().GL_EXT_framebuffer_object;
		
		if (!FBOEnabled)
			return;
		
		IntBuffer buffer = ByteBuffer.allocateDirect(1*4).order(ByteOrder.nativeOrder()).asIntBuffer(); // allocate a 1 int byte buffer
		EXTFramebufferObject.glGenFramebuffersEXT( buffer ); // generate
		myFBOId = buffer.get();
		
		EXTFramebufferObject.glBindFramebufferEXT( EXTFramebufferObject.GL_FRAMEBUFFER_EXT, myFBOId );
		EXTFramebufferObject.glFramebufferTexture2DEXT( EXTFramebufferObject.GL_FRAMEBUFFER_EXT, EXTFramebufferObject.GL_COLOR_ATTACHMENT0_EXT,
		                GL11.GL_TEXTURE_2D, m_texture.getTextureID(), 0);
	}
	
	private void CreateTexture()
	{
		/*	m_iTextureID = GL11.glGenTextures();
    		// initialize color texture
    		GL11.glBindTexture(GL11.GL_TEXTURE_2D, m_iTextureID);									// Bind the colorbuffer texture
    		GL11.glTexParameterf(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER, GL11.GL_LINEAR);				// make it linear filterd
    		GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGBA8, m_iWidth, m_iHeight, 0,GL11.GL_RGBA, GL11.GL_INT, (java.nio.ByteBuffer) null);	// Create the texture data
		*/
		
		try
		{
			m_texture = InternalTextureLoader.get().createTexture(m_iWidth, m_iHeight, GL11.GL_TEXTURE_2D);
		} catch (IOException e)
		{
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}

	public void TestDraw()
	{
		GL11.glLoadIdentity();
		
		GL11.glColor4f(1,0,0,1);
		Graphics.DrawSquare(0, 0, m_iWidth, m_iHeight);
		
		drawn = true;
	}
	
	public void Bind()
	{
		GL11.glBindTexture(GL11.GL_TEXTURE_2D, 0);
		EXTFramebufferObject.glBindFramebufferEXT( EXTFramebufferObject.GL_FRAMEBUFFER_EXT, myFBOId);
		GL11.glPushAttrib(GL11.GL_VIEWPORT_BIT);
		GL11.glViewport( 0, 0, m_iWidth, m_iHeight );
		
		GL11.glMatrixMode(GL11.GL_PROJECTION);
		GL11.glLoadIdentity();
		
		GL11.glOrtho(0, m_iWidth, m_iHeight, 0, -1, 1);
		GL11.glMatrixMode(GL11.GL_MODELVIEW);
		GL11.glLoadIdentity();
		
		GL11.glClear(GL11.GL_COLOR_BUFFER_BIT);
	}
	
	public void UnBind()
	{
		EXTFramebufferObject.glBindFramebufferEXT( EXTFramebufferObject.GL_FRAMEBUFFER_EXT, 0);
		GL11.glPopAttrib();
		
		GL11.glMatrixMode(GL11.GL_PROJECTION);
		GL11.glLoadIdentity();
		GL11.glOrtho(0, Display.getWidth(), Display.getHeight(), 0, -1, 1);
		GL11.glMatrixMode(GL11.GL_MODELVIEW);
		GL11.glLoadIdentity();
	}
	
	public int GetTextureID()
	{
		return m_texture.getTextureID();
	}

	public boolean Drawn()
	{
		return drawn;
	}
}