/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */
package com.tecnosens.ladon.streaming;

import com.jogamp.common.nio.Buffers;
import com.jogamp.opengl.util.awt.TextRenderer;
import java.awt.Font;
import java.nio.FloatBuffer;
import java.nio.IntBuffer;
import javax.media.opengl.GL;
import javax.media.opengl.GL2;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.awt.GLCanvas;
import javax.media.opengl.glu.GLU;

/**
 *
 * @author Matteo Battaglio
 */
public class JOGLTextRenderingCanvas extends GLCanvas implements GLEventListener {
    
    private static final float[] quadVertexArray = {-1.0f, -1.0f, 0.0f,
                                                    -1.0f,  1.0f, 0.0f,
                                                     1.0f, -1.0f, 0.0f,
                                                     1.0f,  1.0f, 0.0f};
    private static final FloatBuffer quadVertices = Buffers.newDirectFloatBuffer(quadVertexArray);
    private int quadVerticesHandle;
    private final GLU glu = new GLU();
    private TextRenderer textRenderer;

    public JOGLTextRenderingCanvas() {
        addGLEventListener(this);
    }

    @Override
    public void init(GLAutoDrawable drawable) {
        GL2 gl = drawable.getGL().getGL2();

        gl.glEnable(GL.GL_DEPTH_TEST);
        gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);

        IntBuffer vboHandles = IntBuffer.allocate(1);
        gl.glGenBuffers(vboHandles.capacity(), vboHandles);
        
        quadVerticesHandle = vboHandles.get(0);
        gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, quadVerticesHandle);
        gl.glBufferData(GL2.GL_ARRAY_BUFFER, quadVertices.capacity() * 4, quadVertices, GL2.GL_STATIC_DRAW);
        gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, 0);
        
        this.textRenderer = new TextRenderer(new Font(Font.SANS_SERIF, Font.BOLD, 14));
        textRenderer.setUseVertexArrays(true);
    }

    @Override
    public void dispose(GLAutoDrawable drawable) {
        
    }

    @Override
    public synchronized void display(GLAutoDrawable drawable) {
        GL2 gl = drawable.getGL().getGL2();
        gl.glEnableClientState(GL2.GL_VERTEX_ARRAY);
        gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
        gl.glLoadIdentity();

        gl.glTranslatef(0.0f, 0.0f, -5.0f);
        gl.glColor4f(1.0f, 1.0f, 1.0f, 1.0f);

        gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, quadVerticesHandle);
        gl.glVertexPointer(3, GL2.GL_FLOAT, 0, 0);
        gl.glDrawArrays(GL2.GL_TRIANGLE_STRIP, 0, 4);
        gl.glBindBuffer(GL2.GL_ARRAY_BUFFER, 0);
        
        gl.glDisableClientState(GL2.GL_VERTEX_ARRAY);
        
        textRenderer.beginRendering(drawable.getWidth(), drawable.getHeight());
        textRenderer.draw("JOGL is fantastic", 10, 10);
        textRenderer.endRendering();
    }

    @Override
    public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
        GL2 gl = drawable.getGL().getGL2();
        if (height <= 0) { // avoid a divide by zero error!
            height = 1;
        }
        float panelAspectRatio = (float) width / (float) height;
        gl.glViewport(0, 0, width, height);
        gl.glMatrixMode(GL2.GL_PROJECTION);
        gl.glLoadIdentity();
        glu.gluPerspective(45.0f, panelAspectRatio, 1.0f, 1000.0f);
        gl.glMatrixMode(GL2.GL_MODELVIEW);
        gl.glLoadIdentity();
    }
    
}