[gl4java-usergroup] dont manage to run feedback properly

[<phi...@ya...>]

hello,

I need to get back the coordinates of the polygons I
have tesselated (with your help, thank you).

So I use the glRenderMode(GL_FEEDBACK).

I've experienced two problems:

I draw:
        if(mode == GL_FEEDBACK)
gl.glPassThrough(1.0f);

        gl.glBegin(GL_POINTS);
        gl.glVertex3f(1f, 1f, 1f);
        gl.glEnd();

        gl.glBegin(GL_POLYGON);
        gl.glVertex3f(0.0f, 0.0f, 0.0f);
        gl.glVertex3f(0.0f, 3.0f, 0.0f);
        gl.glVertex3f(4.0f, 3.0f, 0.0f);
        gl.glVertex3f(6.0f, 1.5f, 0.0f);
        gl.glVertex3f(4.0f, 0.0f, 0.0f);
        gl.glEnd();




then I parse the feedbackBuffer:
(with: gl.glFeedbackBuffer(60, GL_3D, feedBuffer);)


    void printBuffer(int size, float[] buffer) {
        int count;
        float token;
        
        count = size;
        
        System.out.println("
***********start*************");
        while(count != 0) 
        {
            token = buffer[size - count];
            count--;
            
            if(token == gl.GL_PASS_THROUGH_TOKEN)
            {
                System.out.println("FLAG " +
gl.GL_PASS_THROUGH_TOKEN + "  " + buffer[size -
count]);
                count--;
            }
            else if(token == gl.GL_POINT_TOKEN)
            {
                System.out.println("POINT " +
gl.GL_POINT_TOKEN);
                count = print3Dvertex(size, count,
buffer);               
            }
            else if(token == 1799.0f)
            {
                System.out.println("FALSE POLYGON " +
"1799.0");
                count = print3Dvertex(size, count,
buffer);
                count = print3Dvertex(size, count,
buffer);
            }
            else if(token == GL_POLYGON_TOKEN)
            {
              System.out.println("TRUE POLYGON " +
gl.GL_POLYGON_TOKEN);
              float nvertices = buffer[size - count];
              count--;
              for (; nvertices > 0; nvertices--)
              {
                print3Dvertex(size, count, buffer);
              }
            }
            else if(token == 1794.0f)
            {
                System.out.println("SUMMIT");
                count = print3Dvertex(size, count,
buffer);
                count = print3Dvertex(size, count,
buffer);
            }
        }
}




Then with "gl.glOrtho(-10.0, 10.0, -10.0, 10.0, 0.0,
100.0);", I get:

***********start*************

FLAG 1792  1.0
POINT 1793
   i=3 : 288.0     i=4 : 216.0     i=5 : 0.060000002  
  
FALSE POLYGON 1799.0
   i=7 : 256.0     i=8 : 192.0     i=9 : 0.06999999   
 
   i=10 : 256.0     i=11 : 264.0     i=12 : 0.06999999
    
SUMMIT
   i=14 : 256.0     i=15 : 264.0     i=16 : 0.06999999
    
   i=17 : 384.0     i=18 : 264.0     i=19 : 0.06999999
    
SUMMIT
   i=21 : 384.0     i=22 : 264.0     i=23 : 0.06999999
    
   i=24 : 448.0     i=25 : 228.0     i=26 : 0.06999999
    
SUMMIT
   i=28 : 448.0     i=29 : 228.0     i=30 : 0.06999999
    
   i=31 : 384.0     i=32 : 192.0     i=33 : 0.06999999
    
SUMMIT
   i=35 : 384.0     i=36 : 192.0     i=37 : 0.06999999
    
   i=38 : 256.0     i=39 : 192.0     i=40 : 0.06999999



but with: "glu.gluPerspective(45.0f, width / height,
0.1f, 100.0f);", I get:

 ***********start*************
FLAG 1792  1.0
POINT 1793
   i=3 : 191.24219     i=4 : 143.4336     i=5 :
0.98431766     
FALSE POLYGON 1799.0
   i=7 : 99.27344     i=8 : 74.45703     i=9 :
0.986701     
   i=10 : 99.27344     i=11 : 322.77344     i=12 :
0.986701     
SUMMIT
   i=14 : 99.27344     i=15 : 322.77344     i=16 :
0.986701     
   i=17 : 540.72656     i=18 : 322.77344     i=19 :
0.986701     
SUMMIT
   i=21 : 540.72656     i=22 : 322.77344     i=23 :
0.986701     
   i=24 : 639.9961     i=25 : 266.9336     i=26 :
0.986701     
SUMMIT
   i=28 : 639.9961     i=29 : 266.9336     i=30 :
0.986701     
   i=31 : 639.9961     i=32 : 130.29688     i=33 :
0.986701     
SUMMIT
   i=35 : 639.9961     i=36 : 130.29688     i=37 :
0.986701     
   i=38 : 540.72656     i=39 : 74.45703     i=40 :
0.986701     
SUMMIT
   i=42 : 540.72656     i=43 : 74.45703     i=44 :
0.986701     
   i=45 : 99.27344     i=46 : 74.45703     i=47 :
0.986701


As you can see, my first problem is that it doesn't
identifies the GL_POLYGON_TOKEN, but each summit of my
polygon identified by a "1794.0" value. Why?

My second problem is that the returned values don't
match with the ones I've entered. I don't understand
at all why they should depend on the kind of
perspective view (I need the coordinates in the 3D
scene).

Could you help me?
thanks.

philippe, student.

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