How to use 'keypressfcn' for making a diffrence?

Hi guys. I have a question.

this is an octave code, prior to start.

making a code which like 3-D simulation. even its scientific accuracy is worst

function orbit 
  clc; clear all; close all;
  
  % Defining specific physical quntaties.
  m1 = 1; m2 = 1E+11;
  G = 6.67384*10^(-11); t=0; dt = 1;
  p1 = [1E+2, 0, 0];
  p2 = [0, 0, 0];
  v1 = [0, sqrt((G*m2)/(p1(1)-p2(1))), 0.05] ;
  v2 = [0, 0, 0];

  % Generating graphic objects.
  % o1 = simulating obj
  % o2 = center massive bulk
  o1p = line('xdata', p1(1), 'ydata', p1(2), 'zdata', p1(3), 'marker', 'o', 'color', 'r');

  r1 = 10;
  n1 = 10;
  phi1 = (-n1:1:n1)'/n1*pi;
  theta1 = (-n1:1:n1)/n1*2*pi;
  u1 = r1*cos(phi1);
  x1 = sqrt(r1^2-u1.^2)*cos(theta1);
  y1 = sqrt(r1^2-u1.^2)*sin(theta1);
  z1 = repmat(u1,1,length(phi1));
  o1s = surf(x1+p1(1), y1+p1(2), z1+p1(3));

  r2 = 30;
  n2 = 10;
  phi2 = (-n2:1:n2)'/n2*pi;
  theta2 = (-n2:1:n2)/n2*2*pi;
  u2 = r2*cos(phi2);
  x2 = sqrt(r2^2-u2.^2)*cos(theta2);
  y2 = sqrt(r2^2-u2.^2)*sin(theta2);
  z2 = repmat(u2,1,length(phi2));
  o2 = surf(x2, y2, z2);
  
% equation of motion. 
  while collision == 0  
    dist = sqrt((p2(1)-p1(1))^2 + (p2(2)-p1(2))^2 + (p2(3)-p1(3))^2);
    uvec12 = [p2(1)-p1(1), p2(2)-p1(2), p2(3)-p1(3)]*(1/dist);
    uvec21 = -uvec12;
    absF = G*m1*m2/((dist)^2);
    F1 = absF*uvec12;
    F2 = absF*uvec21;
    dv1 = (F1/m1)*dt;

    p1 = p1 + v1*dt;
    v1 = v1 + dv1*dt;
    absv = sqrt(v1(1)^2 + v1(2)^2 + v1(3)^2);
    uvec_v = v1/absv;

% chek the movement  through o1, auto-scaled 3D view and xy-plane.
    axes(axFPS)
    set(o1s, 'xdata', x1+p1(1), 'ydata', y1+p1(2), 'zdata', z1+p1(3));
    campos([p1(1)-uvec_v(1), p1(2)-uvec_v(2), p1(3)-uvec_v(3)]);
    camup([0, 0, 1]);
    view([p1(1), p1(2), p1(3)]);

    axes(axTPS)
    o1p = line('xdata', p1(1), 'ydata', p1(2), 'zdata', p1(3), 'marker', 'o');
    xlim([-200,200]); ylim([-200,200]); zlim([-200, 200]);
    view(3);
  
    axes(axxy)
    o1p = line('xdata', p1(1), 'ydata', p1(2), 'zdata', p1(3), 'marker', 'o');
    xlim([-200,200]); ylim([-200,200]); zlim([-200, 200]);
    view(0, 90);
  
    drawnow;
  end
  

accutally, i want to put 'some acceleration' .

if i press 'space bar', then the v1 = v1 + v1*(5E-2). % toward its direction

i press 'c', then the v1 = v1 - v1*(5E-2) % deceleration.

i press 'a' , then v1 = v1 + [-v1(2), v1(1)]*(5E-2) % left to the direction of tavel.

i press 'd', then v1 = v1 + [v1(2), -v1(1)]*(5E-2) % right to the direction of travel

i attempt to use 'keypressfcn', in the while loop

but it doesn't work well. what can i do?

hope you have a nice day. thank you for reading guys.

while colllision == 0;
  ...
  set(fig ,'keypressfcn', @move_coltrol)
endwhile

% another script, named 'move_control.m'
function move_control(scr, eventdata)
  
  k = eventdata.Key
  switch k
    case 'space'
      t = t + dt;
      v1 = v1 + v1*(5E-2);
      p1 = p1 + v1*dt;
    case 'c'
      t = t + dt;
      v1 = v1 - v1*(5E-2);
      p1 = p1 + v1*dt;
    % 'a' & 'd' accelerate only 'x, y velocity'
    case 'a'
      t = t + dt;
      v1 = v1 + [-v1(2), v1(1), 0]*(5E-2);
      p1 = p1 + v1*dt;
    case 'd'
      t = t + dt;
      v1 = v1 + [v1(2), -v1(1), 0]*(5E-2);
  endswitch
endfunction