Riven external commands
Riven scripts make use of "external commands" to perform complex actions. External commands are code blocks living outside Mohawk files (hence "external"); probably they are part of the engine executable itself. Many complex devices in the game are implemented with external commands (for example the domes and the fire marbles puzzle); this is bad news because no reverse-engineering can be done on them easily. An alternative engine would have to implement custom code for those devices.
This is the first step in understanding the role of each external command. This list has been put together by looking into NAME 3 resources, which store external command names used within each stack. Arguments have been found or guessed by reading scripts.
Each command is reported in a way similar to C functions: command_name(argument1, argument2...). Names without trailing '()' have not yet been investigated.
- 1 a_Data
- 2 b_Data
- 3 g_Data
- 4 j_Data
- 5 o_Data
- 6 p_Data
- 7 r_Data
- 8 t_Data
Used in the main menu card. Hides the "setup" (or "play riven") button by filling the hotspot rectangle with black and disabling the hotspot.
Called when clicking the "continue" button in the "volume adjustment" card.
Called after loading Atrus's journal card.
xaatrusbookback(), xaatrusbookprevpage(), xaatrusbooknextpage()
Called when clicking hotspots in Atrus's journal card.
Called after loading Catherine's journal card.
xacathbookback(), xacathbookprevpage(), xacathbooknextpage()
Called when clicking hotspots in Catherine's journal card.
xtrapbookback(), xatrapbookclose(), xatrapbookopen()
Called when clicking hotspots in the trap book card.
Called by the display update handler of card 278 (Gehn's lab journal). It must display the correct picture since the script doesn't.
Called by two hotspots of card 278 (Gehn's lab journal). They must handle the correct variable (probably blabbook) and update the display accordingly, since the script does nothing.
Called by several cards in their load handler (e.g. card 282, 284, 286, 288, 289).
Used by hotspots in cards 282 and 284 when acting on the boiler controls. It can have one or two args, both taking small numbers (1 to 4).
Used by hotspots in card 284 when acting on the boiler controls. The command is invoked towards the end of the scripts. Among other things it probably reloads (or redraws) the card to reflect the updated controls, as the scripts don't.
Reacts to mouse movements to let the user control the steam valve at the center of the lake (card 415). It must set variable bvalve accordingly.
The mouse tracking algorithm looks very complicated.
Called by the chipper lever hotspot (card 498) when the steam is correctly directed to the chipper. It must play the MLST record with code=2. Why an external?
Start the "flies" realtime effect. u0 seems always 0, u1 is a small number (< 10).
The effect is quite complicated as it randomly moves "flies", which look like tiny icons, around the card. Depending on parameters, their number seems to vary and different kinds of flies may be introduced (e.g. blinking ones).
Called when clicking on the handle inside the jungle elevator, when the elevator is at the top. It must track mouse movements, play the elevator movie and set involved variables.
Apparently, the algorithm is triggered by a single mouse movement, directed towards the bottom.
Called when clicking on the handle inside the jungle elevator, when the elevator is at ground level. It must track mouse movements, play the elevator movie and set involved variables.
Apparently, the algorithm is triggered by single mouse movements, directed towards the top or the bottom.
Called when clicking on the handle inside the jungle elevator, when the elevator is underground. It must track mouse movements, play the elevator movie and set involved variables.
Apparently, the algorithm is triggered by a single mouse movement, directed towards the top.
Called when using the whark toy in the school (card 769). It must take care of playing the correct movies and all. Apparently it uses the jwharkpos variable to know the toy position.
- xbookclick(movie_sref, start_time, end_time, u0)
Called when hitting the telescope button in card 137. Which external will be called depends on the state of variable ttelehandle (0→up, 1→down). The externals must
- inspect ttelecover, ttelepin, ttelescope, ttelevalve and ttelehandle
- increment/decrement ttelescope if needed
- play the correct movie span and the correct sound
- take care of playing the ending sequence if the variables are set correctly.
Called when clicking the telescope cover buttons. button is the button number (1...5).
xtatrusgivesbooks(), xtchotakesbook(), xthideinventory()
Called in this sequence in the "open card" handler for card 155, which is where the intro movie sequence takes place.
Called on display update of card 223: it must draw the marbles at the correct locations in the waffle plate. This is not trivial since prespective must be applied! The marble icons are located in separate tBMP resources (IDs 526-531 in the CD version).
Called in load handler of card 225. Probably it takes care of moving the marble hotspots to the right locations.
Called on display update of card 225. Probably it takes care of drawing the waffle plate with the marbles at the right locations.
Called by marble hotspots in card 225, on mouse down. It must track mouse movements until mouse up, determine the new marble location, set any involved variable and load the card.