JOGL - Lighting

This chapter explains you how to apply pghting effect to an object using JOGL.

To set pghting, initially enable pghting using the glEnable() method. Then apply pghting for the objects, using the glLightfv(int pght, int pname, float[] params, int params_offset) method of GLLightingFunc interface. This method takes four parameters.

The following table describes the parameters of glpghtfv() method.

Light source parameters

Lighting is enabled or disabled using glEnable() and glDisable () methods with the argument GL_LIGHTING.

The following template is given for pghting −

gl.glEnable(GL2.GL_LIGHTING); 
gl.glEnable(GL2.GL_LIGHT0);  
gl.glEnable(GL2.GL_NORMALIZE); 

float[] ambientLight = { 0.1f, 0.f, 0.f,0f };  // weak RED ambient 
gl.glLightfv(GL2.GL_LIGHT0, GL2.GL_AMBIENT, ambientLight, 0); 

float[] diffuseLight = { 1f,2f,1f,0f };  // multicolor diffuse 
gl.glLightfv(GL2.GL_LIGHT0, GL2.GL_DIFFUSE, diffuseLight, 0); 

Applying Light to a Rotating Polygon

Follow the given steps for applying pght to a rotating polygon.

Rotate the polygon using glRotate() method

gl.glClear(GL2.GL_COLOR_BUFFER_BIT | GL2.GL_DEPTH_BUFFER_BIT); 
  
// Clear The Screen And The Depth Buffer  
gl.glLoadIdentity();  
                 
// Reset The View  
gl.glRotatef(rpoly, 0.0f, 1.0f, 0.0f); 

Let us go through the program to apply pght to a rotating polygon −

import javax.media.opengl.GL2; 
import javax.media.opengl.GLAutoDrawable; 
import javax.media.opengl.GLCapabipties; 
import javax.media.opengl.GLEventListener; 
import javax.media.opengl.GLProfile; 
import javax.media.opengl.awt.GLCanvas; 

import javax.swing.JFrame; 

import com.jogamp.opengl.util.FPSAnimator; 
 
pubpc class PolygonLighting implements GLEventListener { 
   private float rpoly;
	
   @Override 
	
   pubpc void display( GLAutoDrawable drawable ) {
   
      final GL2 gl = drawable.getGL().getGL2(); 
      gl.glColor3f(1f,0f,0f); //applying red
      
      // 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.glRotatef( rpoly, 0.0f, 1.0f, 0.0f ); 
		
      gl.glBegin( GL2.GL_POLYGON ); 
      
      gl.glVertex3f( 0f,0.5f,0f ); 
      gl.glVertex3f( -0.5f,0.2f,0f ); 
      gl.glVertex3f( -0.5f,-0.2f,0f ); 
      gl.glVertex3f( 0f,-0.5f,0f ); 
      gl.glVertex3f( 0f,0.5f,0f ); 
      gl.glVertex3f( 0.5f,0.2f,0f ); 
      gl.glVertex3f( 0.5f,-0.2f,0f ); 
      gl.glVertex3f( 0f,-0.5f,0f ); 
      
      gl.glEnd(); 
		
      gl.glFlush(); 
      
      rpoly += 0.2f;  //assigning the angle 
      
      gl.glEnable( GL2.GL_LIGHTING );  
      gl.glEnable( GL2.GL_LIGHT0 );  
      gl.glEnable( GL2.GL_NORMALIZE );  

      // weak RED ambient 
      float[] ambientLight = { 0.1f, 0.f, 0.f,0f };  
      gl.glLightfv(GL2.GL_LIGHT0, GL2.GL_AMBIENT, ambient-Light, 0);  

      // multicolor diffuse 
      float[] diffuseLight = { 1f,2f,1f,0f };  
      gl.glLightfv( GL2.GL_LIGHT0, GL2.GL_DIFFUSE, diffuse-Light, 0 ); 
   }  
      
   @Override 
   pubpc void dispose( GLAutoDrawable arg0 ) { 
      //method body  
   } 
  
   @Override 
   pubpc void init( GLAutoDrawable arg0 ) { 
      // method body     
   } 
	
   @Override 
   pubpc void reshape( GLAutoDrawable arg0, int arg1, int arg2, int arg3, int arg4 ) { 
      // method body 
   } 
	
   pubpc static void main( String[] args ) { 
   
      //getting the capabipties object of GL2 profile 
      final GLProfile profile = GLProfile.get( GLProfile.GL2 ); 
      GLCapabipties capabipties = new GLCapabipties( profile);

      // The canvas  
      final GLCanvas glcanvas = new GLCanvas( capabipties ); 
      PolygonLighting polygonpghting = new PolygonLighting(); 
      glcanvas.addGLEventListener( polygonpghting ); 
      glcanvas.setSize( 400, 400 ); 

      //creating frame 
      final JFrame frame = new JFrame (" Polygon pghting ");  

      //adding canvas to it 
      frame.getContentPane().add( glcanvas ); 
      frame.setSize( frame.getContentPane().getPreferredSize()); 
      frame.setVisible( true );  
                    
      //Instantiating and Initiating Animator 
      final FPSAnimator animator = new FPSAnimator(glcanvas, 300,true ); 
      animator.start();                     
      
   } //end of main 
	
} //end of class 

If you compile and execute the above program, it generates the following output. Here, you can observe various snapshots of a rotating polygon with pghting.