Hey all,

I'm trying to get some openGL stuffs working (trying to go around the inbuilt processing library in the hope of achieving Fancier Effects) but I seem to be stumbling all over the place. I've been trying to get some basic lighting into one of the openGL examples - it runs, but er... doesn't seem to lighting the spinning object. Any ideas?  

Also, sorry for not using "Copy for Discourse" - it was throwing up an error! My lucky day eh?

Thanks a lot,

s.

import javax.media.opengl.*;
import processing.opengl.*;
import java.nio.*;
import com.sun.opengl.util.*;

float a;

PGraphicsOpenGL pgl;
GL gl;

void setup() {
   
 size(800, 600, OPENGL);
 pgl = (PGraphicsOpenGL) g;  // g may change
 gl = pgl.gl;

 gl.glShadeModel(GL.GL_SMOOTH);
 gl.glClearColor(0.0, 0.0, 0.0, 0.0);
 
 
 FloatBuffer mat_specular = BufferUtil.newFloatBuffer(4);
 mat_specular.put(1.0);
 mat_specular.put(1.0);
 mat_specular.put(1.0);
 mat_specular.put(1.0);
 
 FloatBuffer mat_shininess = BufferUtil.newFloatBuffer(1);
 mat_shininess.put(50.0);
 
 FloatBuffer light_position = BufferUtil.newFloatBuffer(4);
 light_position.put(1.0);
 light_position.put(1.0);
 light_position.put(1.0);
 light_position.put(0.0);
 
 FloatBuffer white_light = BufferUtil.newFloatBuffer(4);
 white_light.put(1.0);
 white_light.put(1.0);
 white_light.put(1.0);
 white_light.put(1.0);
 
 FloatBuffer lmodel_ambient = BufferUtil.newFloatBuffer(4);
 lmodel_ambient.put(1.0);
 lmodel_ambient.put(1.0);
 lmodel_ambient.put(1.0);
 lmodel_ambient.put(1.0);
 
 gl.glMaterialfv(GL.GL_FRONT, GL.GL_SPECULAR, mat_specular);
 gl.glMaterialfv(GL.GL_FRONT, GL.GL_SHININESS, mat_shininess);
 gl.glLightfv(GL.GL_LIGHT0, GL.GL_POSITION, light_position);
 gl.glLightfv(GL.GL_LIGHT0, GL.GL_DIFFUSE, white_light);
 gl.glLightfv(GL.GL_LIGHT0, GL.GL_SPECULAR, white_light);
 gl.glLightModelfv(GL.GL_LIGHT_MODEL_AMBIENT, lmodel_ambient);
 
 gl.glEnable(GL.GL_LIGHTING);
 gl.glEnable(GL.GL_LIGHT0);
 gl.glEnable(GL.GL_DEPTH_TEST);  
 
}

void draw() {

 gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
 gl = pgl.beginGL();  // always use the GL object returned by beginGL
 
 gl.glColor4f(0.7, 0.7, 0.7, 0.8);
 gl.glTranslatef(width/2, height/2, 0);
 gl.glRotatef(a, 1, 0, 0);
 gl.glRotatef(a*2, 0, 1, 0);
 gl.glRectf(-200, -200, 200, 200);
 gl.glRotatef(90, 1, 0, 0);
 gl.glRectf(-200, -200, 200, 200);
 
 pgl.endGL();
 
 gl.glFlush();
 
 a += 0.5;
}

Er... yeah, just got rid of the float buffers and used a float array followed by a int offset (which I set to 0 as I don't really understand what it does...) and that er... fixed it. I feel quite embarrassed now. But anyway, here's the working code! Hope it at least saves someone else a headache!

s.


import javax.media.opengl.*;
import processing.opengl.*;
import java.nio.*;
import com.sun.opengl.util.*;

float a;

PGraphicsOpenGL pgl;
GL gl;
GLUT glut = new GLUT();;

FloatBuffer mat_specular, mat_shininess, light_position, white_light, lmodel_ambient;

void setup() {
   
 size(800, 600, OPENGL);
 pgl = (PGraphicsOpenGL) g;  // g may change
 gl = pgl.gl;

 gl.glShadeModel(GL.GL_SMOOTH);
 gl.glClearColor(1.0, 1.0, 1.0, 1.0);
 
 mat_specular = BufferUtil.newFloatBuffer(4);
 mat_specular.put(1.0);
 mat_specular.put(0.0);
 mat_specular.put(0.0);
 mat_specular.put(1.0);
 
 mat_shininess = BufferUtil.newFloatBuffer(1);
 mat_shininess.put(500.0);
 
 light_position = BufferUtil.newFloatBuffer(4);
 light_position.put(1.0);
 light_position.put(1.0);
 light_position.put(1.0);
 light_position.put(1.0);
 
 white_light = BufferUtil.newFloatBuffer(4);
 white_light.put(1.0);
 white_light.put(1.0);
 white_light.put(1.0);
 white_light.put(1.0);
 
 lmodel_ambient = BufferUtil.newFloatBuffer(4);
 lmodel_ambient.put(1.0);
 lmodel_ambient.put(1.0);
 lmodel_ambient.put(1.0);
 lmodel_ambient.put(1.0);
 
 gl.glMaterialfv(GL.GL_FRONT, GL.GL_SPECULAR, new float[]{1.0, 0.0, 0.0, 1.0}, 0);
 gl.glMaterialfv(GL.GL_FRONT, GL.GL_SHININESS, new float[]{0.0, 0.0, 1.0, 1.0}, 0);
 gl.glLightfv(GL.GL_LIGHT0, GL.GL_POSITION, new float[]{1.0, 1.0, 1.0, 1.0}, 0);
 gl.glLightfv(GL.GL_LIGHT0, GL.GL_DIFFUSE, new float[]{1.0, 1.0, 1.0, 1.0}, 0);
 gl.glLightfv(GL.GL_LIGHT0, GL.GL_SPECULAR, new float[]{1.0, 1.0, 1.0, 1.0}, 0);
 gl.glLightModelfv(GL.GL_LIGHT_MODEL_AMBIENT, new float[]{1.0, 0.0, 0.0, 1.0}, 0);
 
}

void draw() {

 gl.glClear(GL.GL_COLOR_BUFFER_BIT | GL.GL_DEPTH_BUFFER_BIT);
   
 gl.glEnable(GL.GL_LIGHTING);
 gl.glEnable(GL.GL_LIGHT0);
 gl.glEnable(GL.GL_DEPTH_TEST);  

 
 gl = pgl.beginGL();  // always use the GL object returned by beginGL
   
 gl.glColor4f(0.7, 0.7, 0.7, 0.8);
 gl.glTranslatef(width/2, height/2, 0);
 gl.glRotatef(a, 1, 0, 0);
 gl.glRotatef(a*2, 0, 1, 0);
 gl.glRectf(-200, -200, 200, 200);
 gl.glRotatef(90, 1, 0, 0);
 gl.glRectf(-200, -200, 200, 200);
 
 pgl.endGL();
 
 gl.glFlush();
 
 a += 0.5;
}

Ah, cheers for the .rewind tip, I'll give it a whirl.

Yes, I know processing can easily do everything above, but there are many things that it can't easily do that I plan to use in my forthcoming patches - accumulation buffer effects such as motion blur and full GLSL support being the 2 most important. Why use Processing at all then right? Well, i prefer Java to C++ (not to mention to lovely environment)! And Processing's built in graphics API makes it quick and easy to prototype/code logic. Also, I get to bin Jitter.

Cheers!

s.

Hi,

Thanks for the heads up on the accumulation buffer - if processing doesn't support it then I guess I just won't be able to use it. The idea of learning C++ makes me quite ill. Maybe it's possible to capture the screen as a texture and feed it back through a GL shader to achieve a similar effect (much as you do in Jitter). Also, thanks for the link, that'll keep me busy for a while ;)

Cheers,

s.