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trs:npc_behaviour [2017/01/04 22:56]
zdimension 		trs:npc_behaviour [2017/11/17 12:19] (current)
stohrendorf
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 +{{indexmenu_n>6}}
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 ====== Non-Player Character Behaviour ====== ====== Non-Player Character Behaviour ======
  
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 Lara is unique player character, so she has a large set of both //control// and //collisional// routines, which are switched depending on her current //state//. Lara is unique player character, so she has a large set of both //control// and //collisional// routines, which are switched depending on her current //state//.
  
-> **Note** +<note> 
->  +In original Tomb Raider source code, notation for collisional and state routines follows two different schemes. For Lara, collisional and control routines are called ''%%lara_col_STATE%%'' and ''%%lara_as_STATE%%'', where ''%%STATE%%'' is the name of the state, like //walk, run, reach//, and so on. 
-> In original Tomb Raider source code, notation for collisional and state routines follows two different schemes. For Lara, collisional and control routines are called ''%%lara_col_STATE%%'' and ''%%lara_as_STATE%%'', where ''%%STATE%%'' is the name of the state, like //walk, run, reach//, and so on. + 
->  +For other entity types, there is more generic scheme: collisional routines are called ''%%NAMECollision%%'', where ''%%NAME%%'' is entity type name, like //CreatureCollision//, and control routines are called ''%%NAMEControl%%'', where ''%%NAME%%'' is entity type name. E.g., bear will have a pair of routines linked to it, named //CreatureCollision// and //BearControl//. 
-> For other entity types, there is more generic scheme: collisional routines are called ''%%NAMECollision%%'', where ''%%NAME%%'' is entity type name, like //CreatureCollision//, and control routines are called ''%%NAMEControl%%'', where ''%%NAME%%'' is entity type name. E.g., bear will have a pair of routines linked to it, named //CreatureCollision// and //BearControl//.+</note>
  
 ===== Entity Scripting ===== ===== Entity Scripting =====
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 Despite the existence of //script files//, here is no any scripting for entity behaviour, like in most contemporary games. This hardcoding makes it difficult to port the earlier Tomb Raider scenarios to the engines of the later games, which could be desirable with their improved hardware support. While textures, models, and animations can be ported, behaviour cannot be. Despite the existence of //script files//, here is no any scripting for entity behaviour, like in most contemporary games. This hardcoding makes it difficult to port the earlier Tomb Raider scenarios to the engines of the later games, which could be desirable with their improved hardware support. While textures, models, and animations can be ported, behaviour cannot be.
  
-However, there is a small change in TR4 and TR5 which indicates that specific entity behaviour can be altered — it’s called //OCB//. It was briefly described in [[meshes_models#object-code-bit|this section]]. OCB is a special value defined for each entity instance, based on which entity can switch the way it acts (most prominent examples are flame emitters, which change their size and emit direction based on OCB, and teeth spikes, which change their orientation in space).+However, there is a small change in TR4 and TR5 which indicates that specific entity behaviour can be altered — it’s called //OCB//. It was briefly described in [[trs:meshes_models#object-code-bit|this section]]. OCB is a special value defined for each entity instance, based on which entity can switch the way it acts (most prominent examples are flame emitters, which change their size and emit direction based on OCB, and teeth spikes, which change their orientation in space).
  
 Sometimes OCB is interpreted as a “packed” field with several values incorporated — like teeth spike OCB contain information about their horizontal and vertical orientation, and also about their “physical” behaviour (stick out constantly, pop-retract in looped manner, or pop-retract just once). Sometimes OCB is interpreted as a “packed” field with several values incorporated — like teeth spike OCB contain information about their horizontal and vertical orientation, and also about their “physical” behaviour (stick out constantly, pop-retract in looped manner, or pop-retract just once).
  
-> **Tip** +<note tip> 
->  +For list of valid entity OCBs in TR4, you may refer to TRLE User’s Manual, although it was written in a big rush, and thus it lacks many existing OCBs for many entities. There are also fan-made OCB lists which are much more comprehensive. 
-> For list of valid entity OCBs in TR4, you may refer to TRLE User’s Manual, although it was written in a big rush, and thus it lacks many existing OCBs for many entities. There are also fan-made OCB lists which are much more comprehensive. + 
->  +As for TR5, no proper OCB list exists for its entity types, so it may be considered a big unknown. 
-> As for TR5, no proper OCB list exists for its entity types, so it may be considered a big unknown.+</note>
  
 However, OCB can’t be seriously called “scripting”, as it also operates with pre-defined hardcoded behaviour. However, OCB can’t be seriously called “scripting”, as it also operates with pre-defined hardcoded behaviour.
  
-> **Note** +<note> 
->  +Recent patches for TR4 game engine (used to play custom levels), like //TREP// and //TRNG//, feature some kind of basic scripting functionality. However, there’s still no sign of //real scripting language// in them, and such scripting is basically specifying pre-defined variables to alter entity behaviour, just like OCB does. 
-> Recent patches for TR4 game engine (used to play custom levels), like //TREP// and //TRNG//, feature some kind of basic scripting functionality. However, there’s still no sign of //real scripting language// in them, and such scripting is basically specifying pre-defined variables to alter entity behaviour, just like OCB does.+</note>
  
 ===== Pathfinding ===== ===== Pathfinding =====
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 This is presumably the way //TRLE// creates boxes for each level: This is presumably the way //TRLE// creates boxes for each level:
  
-* For each sector, extend one axis until a height difference is reached.  +  * For each sector, extend one axis until a height difference is reached.  
-* Then extend this row (or column) perpendicular until another height difference is reached. This is a rectangle with the same height and it //defines a box//. +  * Then extend this row (or column) perpendicular until another height difference is reached. This is a rectangle with the same height and it //defines a box//. 
-* Do the same with the other axis first, and you get another box. +  * Do the same with the other axis first, and you get another box. 
-* Repeat this process for every sector, maybe extending into neighbor rooms through the portals. +  * Repeat this process for every sector, maybe extending into neighbor rooms through the portals. 
-* Make sure that there are no any duplicate boxes. +  * Make sure that there are no any duplicate boxes.
- +
-On a per-room basis, we can have up to 14 boxes.+
  
 There are two variations of box structure — one for TR1 and another for TR2 and any other game version. There are two variations of box structure — one for TR1 and another for TR2 and any other game version.
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 }; };
 </code> </code>
-In ''%%OverlapIndex%%'', the high bit is sometimes set; this occurs in front of swinging doors and the like. That basically means they are unpassable by large enemies, like the T-Rex.+The ''%%OverlapIndex%%'' contains a block mask for path finding by enemies in two highest bits: Bit 15 (blockable) and bit 14 (blocked). The first one marks it as unpassable by large enemies, like the [[:items:details:tr1:trex|T-Rex (ID 18)]], the [[:items:details:tr1:mutant|Mutant (ID 20)]] or the [[:items:details:tr1:centaur|Centaur (ID 23)]] and is always set behind doors. The second one marks it unpassable for other enemies and is set for movable blocks (if blockable bit is set), for closed doors and for some flip maps (set at start).
  
 === Overlaps === === Overlaps ===
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 Since TR3, in addition to pathfinding data structures, there are now special //AI objects//, which are used in a node-like manner, defining specific action, like wandering between two points, guarding specific point or running to specific place in case Lara is around. For example, MP Guards in TR3’s “Area 51” may patrol specific area when they are limited by special //AI_PATROL// object. Since TR3, in addition to pathfinding data structures, there are now special //AI objects//, which are used in a node-like manner, defining specific action, like wandering between two points, guarding specific point or running to specific place in case Lara is around. For example, MP Guards in TR3’s “Area 51” may patrol specific area when they are limited by special //AI_PATROL// object.
  
-> **Note** +<note> 
->  +Not every NPC is “taught” to work with AI objects — usually, only “smart” human enemies or friends can take advantage of them. Analyzing level files with utilities like //FexInspect// may help understanding particular AI object setup and learn which NPCs can actually work with them. 
-> Not every NPC is “taught” to work with AI objects — usually, only “smart” human enemies or friends can take advantage of them. Analyzing level files with utilities like //FexInspect// may help understanding particular AI object setup and learn which NPCs can actually work with them.+</note>
  
 Specific set of AI objects and their respective entity type IDs are different across game versions, but types themselves largely remained unchanged from TR3 to TR5. Here are they: Specific set of AI objects and their respective entity type IDs are different across game versions, but types themselves largely remained unchanged from TR3 to TR5. Here are they:
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   * **AI_FOLLOW** — Used primarily with friendly NPCs, and makes them wait for Lara and then “lead” her to specific point. For such behaviour, one AI_FOLLOW object must be placed in the same sector as NPC, and second AI_FOLLOW object must be placed on target point. If Lara shoots NPC affected with AI_FOLLOW behaviour, he will abandon it and become hostile.   * **AI_FOLLOW** — Used primarily with friendly NPCs, and makes them wait for Lara and then “lead” her to specific point. For such behaviour, one AI_FOLLOW object must be placed in the same sector as NPC, and second AI_FOLLOW object must be placed on target point. If Lara shoots NPC affected with AI_FOLLOW behaviour, he will abandon it and become hostile.
  
-> **Note** +<note> 
->  +If there is a HEAVYTRIGGER under an AI_AMBUSH or AI_PATROL object, the enemy will activate it only when he gets there. 
-> If there is a HEAVYTRIGGER under an AI_AMBUSH or AI_PATROL object, the enemy will activate it only when he gets there.+</note>
  
 {{:icons:tr4.png?nolink|TR4 only}}{{:icons:tr5.png?nolink|TR5 only}} TR4 introduced three additional AI objects, **AI_X1**, **AI_X2** and **LARA_START_POS**. First two are used, for example, with SAS Guards in //Cairo// story arc. When AI_X1 object is placed in the same sector with SAS Guard, he will prefer to shoot grenades instead of bullets. If another SAS Guard with AI_X2 is activated nearby, then first one will stop shooting grenades, and second one will shoot them instead. {{:icons:tr4.png?nolink|TR4 only}}{{:icons:tr5.png?nolink|TR5 only}} TR4 introduced three additional AI objects, **AI_X1**, **AI_X2** and **LARA_START_POS**. First two are used, for example, with SAS Guards in //Cairo// story arc. When AI_X1 object is placed in the same sector with SAS Guard, he will prefer to shoot grenades instead of bullets. If another SAS Guard with AI_X2 is activated nearby, then first one will stop shooting grenades, and second one will shoot them instead.
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 ==== AI Data Block in TR4-5 ==== ==== AI Data Block in TR4-5 ====
  
-Beginning with TR4, AI objects are //not kept along with other entities//. Instead, they have their own structure, which is basically simplified [[meshes_models#tr4_entity|[tr4_entity]]] structure, and moved to separate data block. This seems reasonable, as the only purpose of AI objects is to serve as “waypoints”, and they have neither //collisional// nor //control// code attached to them.+Beginning with TR4, AI objects are //not kept along with other entities//. Instead, they have their own structure, which is basically simplified [[trs:meshes_models#tr4_entity|[tr4_entity]]] structure, and moved to separate data block. This seems reasonable, as the only purpose of AI objects is to serve as “waypoints”, and they have neither //collisional// nor //control// code attached to them.
  
 The format of AI object structure as follows: The format of AI object structure as follows:
trs/npc_behaviour.1483566992.txt.gz · Last modified: 2017/01/04 22:56 by zdimension
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