Color Rendering Probem - Java-Gaming.org

TomUPB

Junior Newbie

« Posted 2012-04-21 22:22:49 »

Hi, I am trying the NeHe lessons and get to No 5. But here an error occurs: The triangle is shown in blue (last color set), the quad is shown correctly:

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package testJOGL; 

import javax.media.opengl.GL2;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.glu.GLU;
 
class Renderer implements GLEventListener 
{
    private GLU glu = new GLU();
 
    public void display(GLAutoDrawable gLDrawable) 
    {
        final GL2 gl = gLDrawable.getGL().getGL2();
        gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT);
        gl.glLoadIdentity();
        gl.glTranslatef(-1.5f, 0.0f, -6.0f);
        gl.glBegin(GL2.GL_TRIANGLES);          // Drawing Using Triangles        
          gl.glColor3f(1.0f, 0.0f, 0.0f);   // Set the current drawing color to red
          gl.glVertex3f( 0.0f, 1.0f, 0.0f);   // Top          
          gl.glColor3f(0.0f, 1.0f, 0.0f);   // Set the current drawing color to green
          gl.glVertex3f(-1.0f,-1.0f, 0.0f);   // Bottom Left          
          gl.glColor3f(0.0f, 0.0f, 1.0f);   // Set the current drawing color to blue
          gl.glVertex3f( 1.0f,-1.0f, 0.0f);   // Bottom Right          
        gl.glEnd();            // Finished Drawing The Triangle
        gl.glTranslatef(3.0f, 0.0f, 0.0f);
        gl.glBegin(GL2.GL_QUADS);              // Draw A Quad
          gl.glColor3f(0.5f, 0.5f, 1.0f);   // Set the current drawing color to light blue
          gl.glVertex3f(-1.0f, 1.0f, 0.0f);   // Top Left
          gl.glVertex3f( 1.0f, 1.0f, 0.0f);   // Top Right
          gl.glVertex3f( 1.0f,-1.0f, 0.0f);   // Bottom Right
          gl.glVertex3f(-1.0f,-1.0f, 0.0f);   // Bottom Left
        gl.glEnd();            // Done Drawing The Quad
        gl.glFlush();
    }
 
 
    public void displayChanged(GLAutoDrawable gLDrawable, boolean modeChanged, boolean deviceChanged) 
    {
       System.out.println("displayChanged called");
    }
 
    public void init(GLAutoDrawable gLDrawable) 
    {
       System.out.println("init() called");
        GL2 gl = gLDrawable.getGL().getGL2();
        gl.glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
        gl.glShadeModel(GL2.GL_FLAT);
        gl.glClearDepth(1.0f);
        gl.glEnable(GL2.GL_DEPTH_TEST);
        gl.glDepthFunc(GL2.GL_LEQUAL);
        gl.glHint(GL2.GL_PERSPECTIVE_CORRECTION_HINT, GL2.GL_NICEST);   
    }
 
    public void reshape(GLAutoDrawable gLDrawable, int x, int y, int width, int height) 
    {
       System.out.println("reshape() called: x = "+x+", y = "+y+", width = "+width+", height = "+height);
        final GL2 gl = gLDrawable.getGL().getGL2();
 
        if (height <= 0) // avoid a divide by zero error!
        {
            height = 1;
        }
 
        final float h = (float) width / (float) height;
 
        gl.glViewport(0, 0, width, height);
        gl.glMatrixMode(GL2.GL_PROJECTION);
        gl.glLoadIdentity();
        glu.gluPerspective(45.0f, h, 1.0, 20.0);
        gl.glMatrixMode(GL2.GL_MODELVIEW);
        gl.glLoadIdentity();
    }
 
 
   public void dispose(GLAutoDrawable arg0) 
   {
      System.out.println("dispose() called");
   }
}
package testJOGL;

import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
 
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLProfile;
import javax.media.opengl.awt.GLCanvas;
import javax.swing.JFrame;
 
public class JOGL_Test1 
{
    public static void main(String[] args) 
    {
       // setup OpenGL Version 2
       GLProfile profile = GLProfile.get(GLProfile.GL2);
       GLCapabilities capabilities = new GLCapabilities(profile);
 
       // The canvas is the widget that's drawn in the JFrame
       GLCanvas glcanvas = new GLCanvas(capabilities);
       glcanvas.addGLEventListener(new Renderer());
       glcanvas.setSize( 640, 480 );
 
        JFrame frame = new JFrame( "Hello World" );
        frame.getContentPane().add( glcanvas);
 
        // shutdown the program on windows close event
        frame.addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent ev) {
                System.exit(0);
            }
        });
 
        frame.setSize( frame.getContentPane().getPreferredSize() );
        frame.setVisible( true );
    }
}

The code is taken from a tutorial from http://schabby.de and other sources as I've tried to fix the problem myself.

Maybe someone could help me? Thx!

TomUPB

Junior Newbie

Re: Color Rendering Probem

« Reply #2 - Posted 2012-04-22 09:52:50 »

I have installed JOGL 2 and imported

1	import javax.media.opengl.GL2;

Thought that would be enough to make sure it's JOGL 2.

TomUPB

Junior Newbie

Re: Color Rendering Probem

« Reply #4 - Posted 2012-04-23 21:25:25 »

I have added JOGL-2.0b633 and GLUEGEN-2.0b480 to my project. After all there cannot be a major problem with my system: both LWJGL and another tutorial on JOGL2.0 work absolutely fine.

I have discovered just one real difference in the code working properly and the code posted above:

1	GLProfile glp = GLProfile.getDefault();

instead of

1	GLProfile profile = GLProfile.get(GLProfile.GL2);

Well, my assignment is to wirte a method receiving a drawable and pushing some GL2-commands to it. As this works now, I am fine.

Thanks for your offered help, guys! Grin