java - OpenGL JOGL camera perspective -

i have drawn 3 boxes each same size having different distance camera. these boxes ought perceived decreasing in size moving away camera. how acheive illusion of distance.

//these 3 planes boxes

  // first plane   gl.glvertex3i(0, 30, 30);   gl.glvertex3i(10, 30, 30);   gl.glvertex3i(10, 20, 30);   gl.glvertex3i(0, 20, 30);    //2nd plane   gl.glvertex3i(20, 20, 37);   gl.glvertex3i(30, 20, 37);   gl.glvertex3i(30, 10, 37);   gl.glvertex3i(20, 10, 37);    //3rd plane   gl.glvertex3i(40, 10, 45);   gl.glvertex3i(50, 10, 45);   gl.glvertex3i(50, 0, 45);   gl.glvertex3i(40, 0, 45); 

//and eye @ code.

gl.glmatrixmode(gl2.gl_modelview); gl.glloadidentity(); glu.glulookat(               35, 15,  10,                25, 15, 30,        0,  1,  0                  );  gl.glmatrixmode(gl2.gl_projection); gl.glloadidentity(); gl.glortho(-50.0, 50.0, -30.0, 30.0, 0.0, 60.0); 

you need use perspective projection, instead of orthographic projection.

instead of calling

gl.glortho(-50.0, 50.0, -30.0, 30.0, 0.0, 60.0); 

you should able replace line with

glu glu = new glu(); glu.gluperspective(60.0, 4.0/3.0, 1.0, 100.0); 

the arguments provided might not correct program, might need adjust them.

the arguments, in order, are: fovy, aspect, znear , zfar.

from manpage:

fovy: specifies field of view angle, in degrees, in y direction.

aspect: specifies aspect ratio determines field of view in x direction. aspect ratio ratio of x (width) y (height).

znear: specifies distance viewer near clipping plane (always positive).

zfar: specifies distance viewer far clipping plane (always positive).

the glu class located here

import javax.media.opengl.glu.glu