Purpose: To create a compass and speedometer that gives you your location and velocity.
What to do: Open cmds.c. Scroll down until you find the ClientCommand function and find a long string of
else if commands. Somewhere in there, insert these lines:
else if (Q_stricmp (cmd, "compass") == 0)
Cmd_Compass_f (ent);
else if (Q_stricmp (cmd, "speedometer") == 0)
Cmd_Speedometer_f (ent);
You have just created two new console commands. One is called "compass" and activates the function
Cmd_Compass_f. The other is called "speedometer" and activates the function Cmd_Speedometer_f. Of
course, neither of these functions exist. Time to rectify that.
Scroll up to above ClientCommand and enter this code:
void Cmd_Compass_f (edict_t *ent)
{
gi.cprintf (ent, PRINT_HIGH, "%d %d %d \n",ent->client->ps.pmove.origin[1], ent->client->ps.pmove.origin[2],
ent->client->ps.pmove.origin[3]); //should be one line
}
What does that rather long command mean? Well, gi.cprintf (ent, PRINT_HIGH, means to put a message
at the top of the client (you) who used the command's screen. "%d %d %d \n", means that this message
should consist of 3 integers and then go to a new line. (Always put \n at the end of such commands.) Now,
what does ent->client->ps.pmove.origin[1] mean? Well, ent is you, which owns a structure called client,
which owns a structure called ps, which has a field called pmove. Pmove is a message sent to the quake2
engine telling what's been happening to the player. The thing is, you can also read this message. One of
pmove's fields is origin, which represents where you are. Origin is a vec3_t, which is a collection of three
floating-point numbers, (which our code will round off to integers for the sake of simplicity) [1], [2], and
[3]. In the case of origin, they are your x, y, and z coordinates. So, this command will display your current
coordinates at the top of the screen.
Now, insert this:
void Cmd_Speedometer_f (edict_t *ent)
{
gi.cprintf (ent, PRINT_HIGH, "%d %d %d \n",ent->client->ps.pmove.velocity[1], ent->client->ps.pmove.velocity[2],
ent->client->ps.pmove.velocity[3]);
}
This, you'll notice, is exactly the same as the compass code, except that origin has been changed to
velocity. Velocity is another vec3_t, representing (you guessed it) your velocity. Pmove has many other
useful vec3_t fields, like weaponangle and viewangle.
How to run this mod: First, compile it. Then put the gamex86.dll into a subdirectory of quake2. Then run
quake2 with quake2 +set game "subdirectoryname". Then start a new game. Go to the console (~) and
type cmd compass (you have to type cmd before any command. It just doesn't seem like you have to for
normal game commands because they are aliased.) and press enter. You will see three coordinates,
representing your location in the map. Move around, and these number change accordingly.
Now try cmd speedometer. If you are standing still, you should get three 0s, because you have no velocity.
Jump and try the command in midair, and you will see that you are moving along the z axis. Run around and
you'll find that you are moving along the x and y axes, depending on which way you're moving.
