I'm trying to implement a GUI system in my game that uses opengl. I know that to do 2D you need to make a call to gl.glOrthof and to do 3D you make a call to gl.glPerspective when the view is set up or changed.

My problem is that idk how I would be able to make a call to both of them at the same time. I'm not a professional with OpenGL or anything I've only been using it for a couple of weeks but I'm not like a complete noob at it either.

These are the two functions in my program which I think are what need to be changed

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   public void onDrawFrame(GL10 gl) {
      gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
      gl.glLoadIdentity();
      gl.glPushMatrix();
      meshes.drawAll(gl);
      gl.glPopMatrix();
   }
   
   public void onSurfaceChanged(GL10 gl, int width, int height) {
      gl.glViewport(0, 0, width, height);
      gl.glMatrixMode(GL10.GL_PROJECTION);
      GLU.gluPerspective(gl, 45.0f, (float)width / (float)height, 0.1f, 1000.0f);
      gl.glMatrixMode(GL10.GL_MODELVIEW);
      gl.glLoadIdentity();
   }

any help is greatly appreciated as this is the only thing stopping me from finishing my game

and also please dont just say "you can check out my project at http://imtoolazytohelpyou.com" because that doesn't help and is a pain in the ass for other people looking for a solution to the same problem

Here are my set/reset ortho utility methods, "gl" is statically referenced.

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   public void resetOrtho()
   {
      gl.glMatrixMode(GL_PROJECTION);                 // Select Projection
      gl.glPopMatrix();                                 // Pop The Matrix
      gl.glMatrixMode(GL_MODELVIEW);                  // Select Modelview
      gl.glPopMatrix();                                 // Pop The Matrix
   }

   public void setOrtho(int width, int height)
   {
      gl.glMatrixMode(GL_PROJECTION);                  // Select Projection
      gl.glPushMatrix();                              // Push The Matrix
      gl.glLoadIdentity();                              // Reset The Matrix
      gl.glOrthof( 0, width, height, 0, -1, 1 );      // Select Ortho Mode
      gl.glMatrixMode(GL_MODELVIEW);                  // Select Modelview Matrix
      gl.glPushMatrix();                              // Push The Matrix
      gl.glLoadIdentity();                              // Reset The Matrix
   }


Take note of your matrix mode when you push/pop

All you have to do is render your 3D scene then pop into ortho mode and draw your GUI then reset ortho and call swapBuffers.

Your code works but I can only display one scene at a time. If I draw the 3D scene then I cant see the 2D scene =(

also, I can't find a function called swapBuffers anywhere

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   public void onDrawFrame(GL10 gl) {   
      gl.glClear(GL10.GL_COLOR_BUFFER_BIT | GL10.GL_DEPTH_BUFFER_BIT);
      gl.glLoadIdentity();
      gl.glPushMatrix();
      scene.drawAll(gl);     //draw my 3D scene
      gl.glPopMatrix();
      setOrtho(gl,50,30);  //Your function
                gui.drawAll(gl);     //draw my 2D GUI
      resetOrtho(gl);     //your function
   }


You're turning off depth testing when you draw the 2d scene I take it?

gl.glDisable(GL10.GL_DEPTH_TEST);