Q: In Aum 21 the tanks have no gravity and if they are up in the air they will not go down the bottom. I know that this code was written for A5 but I'm trying to get it to work for A6; can you help?
A: Use the project from Aum36's faq as a base; it includes gravity, as well as slope alignment for a car. Click here to download the modified project.

Q: I was wondering if you could show me how to set up a rotating camera? Say you are in a room and you press 's' to start the camera rotating in around 360 degrees and then press 's' to stop it.
A: Use the code below:

var camera_mode = 0;
var rotation_speed = 1.5;

view rotating_camera{}

starter set_camera()
{
   sleep (1); // wait a bit more
   rotating_camera.pos_x = 0;
   rotating_camera.pos_y = 0;
   rotating_camera.size_x = screen_size.x;
   rotating_camera.size_y = screen_size.y;
}

function switch_cameras()
{
   if (player == null) {return;}
   camera_mode += 1;
   if (camera_mode %2 == 1) // rotating camera?
   {
      rotating_camera.x = player.x;
      rotating_camera.y = player.y;
      rotating_camera.z = player.z;
      rotating_camera.pan = player.pan;
      rotating_camera.tilt = player.tilt;
      rotating_camera.roll = player.roll;
      rotating_camera.visible = on;
      camera.visible = off;
      while (camera_mode % 2 == 1)
      {
         rotating_camera.pan += rotation_speed * time;
         wait (1);
      }
   }
   else
  {
     rotating_camera.visible = off;
     camera.visible = on;
   }
}

on_s = switch_cameras;

Q: I'd need a little jump-pad type code. I've positioned entities throughout the level, and when the character runs on them I'd like him to be thrusted about 30 - 40 scaled feet into the air. I'd also like to have a sound file associated with the trigger.
A: Click here to download the code for my old "Maniac Miner" project from Aum3 that now includes jump pads as well.

Q: I want to determine exactly where the bullet hits the entity. How can I get the closest vertex of the model?
A: Use the code below:

action enemy // attach this action to your enemy model
{
  my.enable_impact = on;
  my.enable_shoot = on;
  my.enable_entity = on;
  my.event = compute_shot_pos;
}

function compute_shot_pos()
{
   var temp_vertex = 0;
   var hit_vertex = 0;
   var index = 1;
   var temp_dist = 0;
   var min_dist = 10000; // set to a big value on purpose
   vec_set(bullet_pos, you.pos); // store bullet's coords before they get lost (before the bullet disappears)
   my.event = null; // don't react to other bullets from now on
   wait (1); // now we can wait for a frame
   while (index < ent_vertices(my)) // get the number of vertices
   {
      vec_for_vertex (temp_vertex, my, index); // store the coordinates of the current vertex in temp_vertex
      temp_dist = vec_dist(bullet_pos.x, temp_vertex.x); // compute the distance from the vertex to the impact coordinates
      if (temp_dist < min_dist) // if we have got a tiny value
      {
         min_dist = temp_dist; // then this will be the closest vertex, at least for now
         hit_vertex = index; // and we store the index
      }
      index += 1; // check the next vertex
   }
   my.event = compute_shot_pos; // the loop has ended, start reacting to other bullets from now on
   // hit_vertex contains the closest vertex number now
}

Q: I'd like to have a panel that can be closed by clicking a small "X" in the upper right corner. Is this possible?
A: Sure. Use the code below:

bmap mypanel_pcx = <mypanel.pcx>;

function close_panel;

panel mypanel_pan
{
   bmap = mypanel_pcx;
   layer = 20;
   pos_x = 250;
   pos_y = 50;
   flags = overlay, refresh, visible;
   on_click = close_panel;
}

function close_panel()
{
   if ((pointer.x > mypanel_pan.pos_x + bmap_width(mypanel_pcx) - 10) && (pointer.y < mypanel_pan.pos_y + 10)) // the "X" has 10x10 pixels
   {
      mypanel_pan.visible = off;
   }
}

Q: How can I create a cone of particles?
A: Use the code below:

bmap effect_tga = <effect.tga>;

function particle_cone();
function fade_particles();

action cone
{
   my.invisible = on;
   my.passable = on;
   while(1)
   {
      effect(particle_cone, 20 * time, my.x, nullvector);
      wait(1);
   }
}

function particle_cone()
{
   temp.x = random(10) - 5;
   temp.y = random(10) - 5;
   temp.z = random(5) + 5;
   vec_set(my.vel_x,temp);
   my.bmap = effect_tga;
   my.size = 2.5;
   my.flare = on;
   my.bright = on;
   my.move = on;
   my.streak = on; // if your engine version supports it
   my.alpha = 80;
   my.lifespan = 50;
   my.function = fade_particles;
}

function fade_particles()
{
   my.alpha -= 2 * time;
   if(my.alpha < 0) // not really needed
   {
      my.lifespan = 0;
   }
}

Q: How can I smoothly fade one view into another?
A: Use the code below:

view second_camera{}

action set_second_camera // place any entity in the level and set its proper position and orientation
{
   my.invisible = on;
   my.passable = on;
   wait (3);
   second_camera.pos_x = 0;
   second_camera.pos_y = 0;
   second_camera.size_x = screen_size.x;
   second_camera.size_y = screen_size.y;
   second_camera.alpha = 0;
   second_camera.transparent = on;
   camera.alpha = 100;
   camera.transparent = on;
   second_camera.x = my.x;
   second_camera.y = my.y;
   second_camera.z = my.z;
   second_camera.pan = my.pan;
   second_camera.tilt = my.tilt;
   second_camera.roll = my.roll;
}

function toggle_cameras()
{
   second_camera.visible = on;
   while (second_camera.alpha < 99)
   {
      second_camera.alpha += 2 * time;
      camera.alpha -= 2 * time;
      wait (1);
   }
   camera.visible = off;
   second_camera.transparent = off;
}

on_t = toggle_cameras;

Q: How can I replace all the "a" characters in a string with "b" characters?
A: Use the example below:

var number_of_characters;
var string_index;

string initial_str;
string replaced_str;
string backup_str;

text tester_txt
{
   layer = 200;
   string = replaced_str;
   flags = visible;
}

function replace_characters()
{
   str_cpy(initial_str, "Mary is an awesome painter");
   number_of_characters = str_len(initial_str);
   string_index = 0;
   str_cpy(replaced_str, "");
   while (string_index < number_of_characters)
   {
      str_cpy (backup_str, initial_str);
      str_clip(backup_str, string_index);
      str_trunc(backup_str, number_of_characters - string_index - 1);
      if (str_cmpi(backup_str, "a") == 1) // found an "a"?
      {
         str_cat(replaced_str, "b"); // replace it with a "b"
      }
      else
      {
         str_cat(replaced_str, backup_str); // keep the current letter
      }
      string_index += 1;
   }
}

on_r = replace_characters;

Q: I'd like to be able to create objects (trees) at runtime and place them in front of the player. How can I do that?
A: Use this example:

string tree_mdl = <tree.mdl>;

function create_tree()
{
   wait (1);
   vec_set (temp.x, my.x);
   temp.z -= 10000;
   trace_mode = ignore_me + ignore_sprites + ignore_models + use_box;
   my.z -= trace (my.pos, temp) + 20;
}

function place_trees()
{
   temp.x = 200; // place the trees 200 quants in front of the player
   temp.y = 0;
   temp.z = 0;
   vec_rotate (temp, player.pan);
   vec_add (temp, player.x);
   ent_create(tree_mdl, temp.x, create_tree); // create the tree
}

on_p = place_trees;