JOGL - Triangle 3D

Dans le chapitre précédent, nous avons vu comment dessiner des formes 3D, ce chapitre vous apprend à dessiner un triangle 3D et à le faire pivoter.

Vous trouverez ci-dessous le programme pour dessiner un triangle 3D et le faire pivoter.

import javax.media.opengl.GL2;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.GLProfile;
import javax.media.opengl.awt.GLCanvas;
import javax.media.opengl.glu.GLU;

import javax.swing.JFrame;

import com.jogamp.opengl.util.FPSAnimator;

public class Triangle3d implements GLEventListener {

   private GLU glu = new GLU();
   private float rtri = 0.0f;
      
   @Override
   public void display(GLAutoDrawable drawable) {
      final GL2 gl = drawable.getGL().getGL2();

      // Clear The Screen And The Depth Buffer
      gl.glClear( GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT );
      gl.glLoadIdentity(); // Reset The View
      gl.glTranslatef( -0.5f, 0.0f, -6.0f ); // Move the triangle
      gl.glRotatef( rtri, 0.0f, 1.0f, 0.0f );
      gl.glBegin( GL2.GL_TRIANGLES ); 
        
      //drawing triangle in all dimensions
      // Front
      gl.glColor3f( 1.0f, 0.0f, 0.0f ); // Red
      gl.glVertex3f( 1.0f, 2.0f, 0.0f ); // Top Of Triangle (Front)
		
      gl.glColor3f( 0.0f, 1.0f, 0.0f ); // Green
      gl.glVertex3f( -1.0f, -1.0f, 1.0f ); // Left Of Triangle (Front)
		
      gl.glColor3f( 0.0f, 0.0f, 1.0f ); // Blue
      gl.glVertex3f( 1.0f, -1.0f, 1.0f ); // Right Of Triangle (Front)
        
      // Right
      gl.glColor3f( 1.0f, 0.0f, 0.0f ); // Red
      gl.glVertex3f( 1.0f, 2.0f, 0.0f ); // Top Of Triangle (Right)
		
      gl.glColor3f( 0.0f, 0.0f, 1.0f ); // Blue
      gl.glVertex3f( 1.0f, -1.0f, 1.0f ); // Left Of Triangle (Right)
		
      gl.glColor3f( 0.0f, 1.0f, 0.0f ); // Green
      gl.glVertex3f( 1.0f, -1.0f, -1.0f ); // Right Of Triangle (Right)
        
      // Left
      gl.glColor3f( 1.0f, 0.0f, 0.0f ); // Red
      gl.glVertex3f( 1.0f, 2.0f, 0.0f ); // Top Of Triangle (Back)
		
      gl.glColor3f( 0.0f, 1.0f, 0.0f ); // Green
      gl.glVertex3f( 1.0f, -1.0f, -1.0f ); // Left Of Triangle (Back)
		
      gl.glColor3f( 0.0f, 0.0f, 1.0f ); // Blue
      gl.glVertex3f( -1.0f, -1.0f, -1.0f ); // Right Of Triangle (Back)
        
      //left
      gl.glColor3f( 0.0f, 1.0f, 0.0f ); // Red
      gl.glVertex3f( 1.0f, 2.0f, 0.0f ); // Top Of Triangle (Left)
		
      gl.glColor3f( 0.0f, 0.0f, 1.0f ); // Blue
      gl.glVertex3f( -1.0f, -1.0f, -1.0f ); // Left Of Triangle (Left)
		
      gl.glColor3f( 0.0f, 1.0f, 0.0f ); // Green
      gl.glVertex3f( -1.0f, -1.0f, 1.0f ); // Right Of Triangle (Left)
		
      gl.glEnd(); // Done Drawing 3d triangle (Pyramid)
      gl.glFlush();
      rtri += 0.2f;
   }
   
   @Override
   public void dispose( GLAutoDrawable drawable ) {
      //method body
   }
   
   @Override
   public void init( GLAutoDrawable drawable ) {
      //method body
   }
   
   @Override
   public void reshape( GLAutoDrawable drawable, int x, int y, int width, int height ) {
	
      // TODO Auto-generated method stub
      final GL2 gl = drawable.getGL().getGL2();
      if(height lt;=;)
         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 static void main( String[] args ) {
   
      // TODO Auto-generated method stub
      final GLProfile profile = GLProfile.get( GLProfile.GL2 );
      GLCapabilities capabilities = new GLCapabilities( profile );
         
      // The canvas
      final GLCanvas glcanvas = new GLCanvas( capabilities );
      Triangle3d triangle = new Triangle3d();
		
      glcanvas.addGLEventListener( triangle );
      glcanvas.setSize( 400, 400 );
		
      final JFrame frame = new JFrame ( "3d Triangle (shallow)" );
		
      frame.getContentPane().add( glcanvas );
      frame.setSize( frame.getContentPane().getPreferredSize() );
      frame.setVisible( true );
		
      final FPSAnimator animator = new FPSAnimator(glcanvas,300,true);
      animator.start();
   }
	
}

Lorsque vous compilez et exécutez le programme ci-dessus, la sortie suivante est générée. Ici, vous avez les instantanés du triangle 3D en rotation. Puisque ce programme n'inclut pas de test de profondeur, le triangle est généré creux.

Pour rendre le triangle solide, vous devez activer le test de profondeur en utilisant glEnable(GL_DEPTH_TEST). L'activation du tampon de profondeur vous donne un écran vide. Cela peut être effacé en effaçant la couleur en utilisantglClear(GL_COLOR_BUFFERBIT | GL_DEPTH_BUFFER_BIT)méthode. Pour activer le test de profondeur dans la méthode init () ou dans leglDisplay() méthode, écrivez le code suivant -

public void init(GLAutoDrawable drawable) {
   final GL2 gl = drawable.getGL().getGL2();
	
   gl.glShadeModel(GL2.GL_SMOOTH);
   gl.glClearColor(0f, 0f, 0f, 0f);
   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);
 }

Ci-dessous est donné le programme pour dessiner un triangle 3D avec test de profondeur.

import javax.media.opengl.GL2;
import javax.media.opengl.GLAutoDrawable;
import javax.media.opengl.GLCapabilities;
import javax.media.opengl.GLEventListener;
import javax.media.opengl.GLProfile;
import javax.media.opengl.awt.GLCanvas;
import javax.media.opengl.glu.GLU;

import javax.swing.JFrame;

import com.jogamp.opengl.util.FPSAnimator;

public class Triangledepthtest implements GLEventListener {

   private GLU glu = new GLU();
   private float rtri = 0.0f; 
	
   @Override
   public void display( GLAutoDrawable drawable ) {
	
      final GL2 gl = drawable.getGL().getGL2();
		
      gl.glShadeModel( GL2.GL_SMOOTH );
      gl.glClearColor( 0f, 0f, 0f, 0f );
      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);

      // Clear The Screen And The Depth Buffer
      gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT); 
      gl.glLoadIdentity(); // Reset The View
      gl.glTranslatef( -0.5f,0.0f,-6.0f ); // Move the triangle
      gl.glRotatef( rtri, 0.0f, 1.0f, 0.0f );
      gl.glBegin( GL2.GL_TRIANGLES ); 

      //drawing triangle in all dimensions
      //front
      gl.glColor3f( 1.0f, 0.0f, 0.0f ); // Red
      gl.glVertex3f( 1.0f, 2.0f, 0.0f ); // Top
		
      gl.glColor3f( 0.0f, 1.0f, 0.0f ); // Green
      gl.glVertex3f( -1.0f, -1.0f, 1.0f ); // Left
		
      gl.glColor3f( 0.0f, 0.0f, 1.0f ); // Blue
      gl.glVertex3f( 1.0f, -1.0f, 1.0f ); // Right)

      //right
      gl.glColor3f( 1.0f, 0.0f, 0.0f );
      gl.glVertex3f( 1.0f, 2.0f, 0.0f ); // Top
		
      gl.glColor3f( 0.0f, 0.0f, 1.0f );
      gl.glVertex3f( 1.0f, -1.0f, 1.0f ); // Left
		
      gl.glColor3f( 0.0f, 1.0f, 0.0f );
      gl.glVertex3f( 1.0f, -1.0f, -1.0f ); // Right

      //left
      gl.glColor3f( 1.0f, 0.0f, 0.0f );
      gl.glVertex3f( 1.0f, 2.0f, 0.0f ); // Top
		
      gl.glColor3f( 0.0f, 1.0f, 0.0f );
      gl.glVertex3f( 1.0f, -1.0f, -1.0f ); // Left 
		
      gl.glColor3f( 0.0f, 0.0f, 1.0f );
      gl.glVertex3f( -1.0f, -1.0f, -1.0f ); // Right 

      //top
      gl.glColor3f( 0.0f, 1.0f, 0.0f );
      gl.glVertex3f( 1.0f, 2.0f, 0.0f ); // Top
		
      gl.glColor3f( 0.0f, 0.0f, 1.0f );
      gl.glVertex3f( -1.0f, -1.0f, -1.0f ); // Left
		
      gl.glColor3f( 0.0f, 1.0f, 0.0f );
      gl.glVertex3f( -1.0f, -1.0f, 1.0f ); // Right
		
      gl.glEnd(); // Done Drawing 3d triangle (Pyramid)

      gl.glFlush();
      rtri += 0.2f;
   }
      
   @Override
   public void dispose( GLAutoDrawable drawable ) {
   }
   
   @Override
   public void init( GLAutoDrawable drawable ) {
	
      final GL2 gl = drawable.getGL().getGL2();
		
      gl.glShadeModel( GL2.GL_SMOOTH );
      gl.glClearColor( 0f, 0f, 0f, 0f );
      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 );
   }
   
   @Override
   public void reshape(GLAutoDrawable drawable, int x, int y, int width, int height ) {
	
      // TODO Auto-generated method stub
      final GL2 gl = drawable.getGL().getGL2();
      if( height <= 0 ) 
         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 static void main( String[] args ) {
	
      // TODO Auto-generated method stub
      final GLProfile profile = GLProfile.get( GLProfile.GL2 );
      GLCapabilities capabilities = new GLCapabilities( profile );
		
      // The canvas
      final GLCanvas glcanvas = new GLCanvas( capabilities );
      Triangledepthtest triangledepthtest = new Triangledepthtest();
		
      glcanvas.addGLEventListener( triangledepthtest );
      glcanvas.setSize( 400, 400 );
		
      final JFrame frame = new JFrame ( "3d Triangle (solid)" );
      frame.getContentPane().add(glcanvas);
      frame.setSize( frame.getContentPane().getPreferredSize() );
      frame.setVisible( true );
      final FPSAnimator animator = new FPSAnimator( glcanvas, 300,true);
		
      animator.start();
   }
	
}

Lorsque vous compilez et exécutez le programme ci-dessus, la sortie suivante est générée.

Ici, vous pouvez voir les instantanés d'un triangle 3D en rotation. Puisque ce programme inclut le code pour le test de profondeur, le triangle est généré solide.