package net.sf.breed.mini.jogl.article;

import java.awt.BorderLayout;
import java.io.IOException;
import java.io.InputStream;

import javax.media.opengl.DebugGL;
import javax.media.opengl.GL;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCanvas;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.glu.GLU;
import javax.media.opengl.glu.GLUquadric;
import javax.swing.JFrame;

import com.sun.opengl.util.FPSAnimator;
import com.sun.opengl.util.texture.Texture;
import com.sun.opengl.util.texture.TextureData;
import com.sun.opengl.util.texture.TextureIO;

/**
 * A minimal JOGL demo.
 * 
 * @author <a href="mailto:kain@land-of-kain.de">Kai Ruhl</a>
 * @since 26 Feb 2009
 */
public class MyJoglCanvasStep5 extends GLCanvas implements GLEventListener {

    /** Serial version UID. */
    private static final long serialVersionUID = 1L;

    /** The GL unit (helper class). */
    private GLU glu;

    /** The frames per second setting. */
    private int fps = 60;

    /** The OpenGL animator. */
    private FPSAnimator animator;

    /** The earth texture. */
    private Texture earthTexture;

    /**
     * A new mini starter.
     * 
     * @param capabilities The GL capabilities.
     * @param width The window width.
     * @param height The window height.
     */
    public MyJoglCanvasStep5(GLCapabilities capabilities, int width, int height) {
        addGLEventListener(this);
    }

    /**
     * @return Some standard GL capabilities (with alpha).
     */
    private static GLCapabilities createGLCapabilities() {
        GLCapabilities capabilities = new GLCapabilities();
        capabilities.setRedBits(8);
        capabilities.setBlueBits(8);
        capabilities.setGreenBits(8);
        capabilities.setAlphaBits(8);
        return capabilities;
    }

    /**
     * Sets up the screen.
     * 
     * @see javax.media.opengl.GLEventListener#init(javax.media.opengl.GLAutoDrawable)
     */
    public void init(GLAutoDrawable drawable) {
        drawable.setGL(new DebugGL(drawable.getGL()));
        final GL gl = drawable.getGL();

        // Enable z- (depth) buffer for hidden surface removal. 
        gl.glEnable(GL.GL_DEPTH_TEST);
        gl.glDepthFunc(GL.GL_LEQUAL);

        // Enable smooth shading.
        gl.glShadeModel(GL.GL_SMOOTH);

        // Define "clear" color.
        gl.glClearColor(0f, 0f, 0f, 0f);

        // We want a nice perspective.
        gl.glHint(GL.GL_PERSPECTIVE_CORRECTION_HINT, GL.GL_NICEST);

        // Create GLU.
        glu = new GLU();

        // Load earth texture.
        try {
            InputStream stream = getClass().getResourceAsStream("earth_1024x512.png");
            TextureData data = TextureIO.newTextureData(stream, false, "png");
            earthTexture = TextureIO.newTexture(data);
        }
        catch (IOException exc) {
            exc.printStackTrace();
            System.exit(1);
        }

        // Start animator.
        animator = new FPSAnimator(this, fps);
        animator.start();
    }

    /**
     * The only method that you should implement by yourself.
     * 
     * @see javax.media.opengl.GLEventListener#display(javax.media.opengl.GLAutoDrawable)
     */
    public void display(GLAutoDrawable drawable) {
        if (!animator.isAnimating()) {
            return;
        }
        final GL gl = drawable.getGL();

        // Clear screen.
        gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);

        // Set camera.
        setCamera(gl, glu, 30);

        // Prepare light parameters.
        float SHINE_ALL_DIRECTIONS = 1;
        float[] lightPos = {-30, 0, 0, SHINE_ALL_DIRECTIONS};
        float[] lightColorAmbient = {0.2f, 0.2f, 0.2f, 1f};
        float[] lightColorSpecular = {0.8f, 0.8f, 0.8f, 1f};

        // Set light parameters.
        gl.glLightfv(GL.GL_LIGHT1, GL.GL_POSITION, lightPos, 0);
        gl.glLightfv(GL.GL_LIGHT1, GL.GL_AMBIENT, lightColorAmbient, 0);
        gl.glLightfv(GL.GL_LIGHT1, GL.GL_SPECULAR, lightColorSpecular, 0);

        // Enable lighting in GL.
        gl.glEnable(GL.GL_LIGHT1);
        gl.glEnable(GL.GL_LIGHTING);

        // Set material properties.
        float[] rgba = {1f, 1f, 1f};
        gl.glMaterialfv(GL.GL_FRONT, GL.GL_AMBIENT, rgba, 0);
        gl.glMaterialfv(GL.GL_FRONT, GL.GL_SPECULAR, rgba, 0);
        gl.glMaterialf(GL.GL_FRONT, GL.GL_SHININESS, 0.5f);

        // Apply texture.
        earthTexture.enable();
        earthTexture.bind();

        // Draw sphere (possible styles: FILL, LINE, POINT).
        GLUquadric earth = glu.gluNewQuadric();
        glu.gluQuadricTexture(earth, true);
        glu.gluQuadricDrawStyle(earth, GLU.GLU_FILL);
        glu.gluQuadricNormals(earth, GLU.GLU_FLAT);
        glu.gluQuadricOrientation(earth, GLU.GLU_OUTSIDE);
        final float radius = 6.378f;
        final int slices = 16;
        final int stacks = 16;
        glu.gluSphere(earth, radius, slices, stacks);
        glu.gluDeleteQuadric(earth);
    }

    /**
     * Resizes the screen.
     * 
     * @see javax.media.opengl.GLEventListener#reshape(javax.media.opengl.GLAutoDrawable,
     *      int, int, int, int)
     */
    public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height) {
        final GL gl = drawable.getGL();
        gl.glViewport(0, 0, width, height);
    }

    /**
     * Changing devices is not supported.
     * 
     * @see javax.media.opengl.GLEventListener#displayChanged(javax.media.opengl.GLAutoDrawable,
     *      boolean, boolean)
     */
    public void displayChanged(GLAutoDrawable drawable, boolean modeChanged, boolean deviceChanged) {
        throw new UnsupportedOperationException("Changing display is not supported.");
    }

    /**
     * @param gl The GL context.
     * @param glu The GL unit.
     * @param distance The distance from the screen.
     */
    private void setCamera(GL gl, GLU glu, float distance) {
        // Change to projection matrix.
        gl.glMatrixMode(GL.GL_PROJECTION);
        gl.glLoadIdentity();

        // Perspective.
        float widthHeightRatio = (float) getWidth() / (float) getHeight();
        glu.gluPerspective(45, widthHeightRatio, 1, 1000);
        glu.gluLookAt(0, 0, distance, 0, 0, 0, 0, 1, 0);

        // Change back to model view matrix.
        gl.glMatrixMode(GL.GL_MODELVIEW);
        gl.glLoadIdentity();
    }

    /**
     * Starts the JOGL mini demo.
     * 
     * @param args Command line args.
     */
    public final static void main(String[] args) {
        GLCapabilities capabilities = createGLCapabilities();
        MyJoglCanvasStep5 canvas = new MyJoglCanvasStep5(capabilities, 800, 500);
        JFrame frame = new JFrame("Mini JOGL Demo (breed)");
        frame.getContentPane().add(canvas, BorderLayout.CENTER);
        frame.setSize(800, 500);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
        canvas.requestFocus();
    }

}