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- | {{anchor: | + | {{indexmenu_n> |
====== 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 // | Lara is unique player character, so she has a large set of both //control// and // | ||
- | > **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 '' |
- | > In original Tomb Raider source code, notation for collisional and state routines follows two different schemes. For Lara, collisional and control routines are called '' | + | |
- | > | + | For other entity types, there is more generic scheme: collisional routines are called '' |
- | > For other entity types, there is more generic scheme: collisional routines are called '' | + | </ |
===== 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# | + | 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# |
Sometimes OCB is interpreted as a “packed” field with several values incorporated — like teeth spike OCB contain information about their horizontal and vertical orientation, | Sometimes OCB is interpreted as a “packed” field with several values incorporated — like teeth spike OCB contain information about their horizontal and vertical orientation, | ||
- | > **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. | + | </ |
However, OCB can’t be seriously called “scripting”, | However, OCB can’t be seriously called “scripting”, | ||
- | > **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. | + | </ |
===== Pathfinding ===== | ===== Pathfinding ===== | ||
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TR engines use three different structures to assist pathfinding. These are //boxes, overlaps, and zones//. Most sectors point to some //box//, the main exceptions being horizontal-portal sectors. Several neighbour sectors may point to the same box. A box is a horizontal rectangle, with corners and height specified; each box also has a pointer into the list of // | TR engines use three different structures to assist pathfinding. These are //boxes, overlaps, and zones//. Most sectors point to some //box//, the main exceptions being horizontal-portal sectors. Several neighbour sectors may point to the same box. A box is a horizontal rectangle, with corners and height specified; each box also has a pointer into the list of // | ||
+ | Several neighbour sectors may point to the same box. Each box also has a pointer into the list of // | ||
This selection is done with the help of the //zones//. These structures of 6 (TR1) or 10 (TR2-TR5) '' | This selection is done with the help of the //zones//. These structures of 6 (TR1) or 10 (TR2-TR5) '' | ||
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{{anchor: | {{anchor: | ||
=== Boxes === | === Boxes === | ||
+ | |||
+ | A box is a horizontal rectangle, with corners and height specified. | ||
+ | |||
+ | This is presumably the way //TRLE// creates boxes for each level: | ||
+ | |||
+ | * 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//. | ||
+ | * 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. | ||
+ | * Make sure that there are no any duplicate 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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uint32_t Xmax; | uint32_t Xmax; | ||
| | ||
- | uint16_t OverlapIndex; | + | uint16_t OverlapIndex; |
}; | }; | ||
</ | </ | ||
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uint8_t Xmax; | uint8_t Xmax; | ||
int16_t TrueFloor; | int16_t TrueFloor; | ||
- | int16_t OverlapIndex; | + | int16_t OverlapIndex; |
}; | }; | ||
</ | </ | ||
- | In '' | + | The '' |
=== Overlaps === | === Overlaps === | ||
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This is a set of lists of neighbouring boxes for each box, each member being a '' | This is a set of lists of neighbouring boxes for each box, each member being a '' | ||
- | Overlaps must be parsed in serial manner, as with // | + | Overlaps must be parsed in serial manner, as with // |
=== Zones === | === Zones === | ||
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</ | </ | ||
The ground zones are for NPCs that travel on the ground, while the fly zones are for flying or swimming NPCs. | The ground zones are for NPCs that travel on the ground, while the fly zones are for flying or swimming NPCs. | ||
+ | |||
+ | ==== Moods ==== | ||
+ | |||
+ | Each mobile NPC in TR may be in a certain //mood//. A mood defines the way creature behaves. The way NPCs change their mood is based on several conditions, mainly on certain enemy implementation. | ||
+ | |||
+ | Most obvious example of mood change is wolf, which can sleep, walk slowly, chase Lara and flee. This change of mood is based on Lara’s position — if Lara is found in any of the box that NPC can reach, mood is changed to //chase//, which means that // | ||
+ | |||
+ | There are another examples of mood changes. In TR3, monkeys are calm unless Lara shoots them. However, this is not the case for level 2 (Temple Ruins), where monkeys are hardcoded to chase Lara on start-up. | ||
+ | |||
+ | {{anchor: | ||
+ | ==== Pathfinding algorithm ==== | ||
+ | |||
+ | For most of TR NPCs, when they are in //chase// mood, pathfinding (and eventual attack) may be broken down to several steps: | ||
+ | |||
+ | * Collect all boxes that are in the same zone as the NPC. | ||
+ | * Find a path using // | ||
+ | * Calculate a random point in the intersection of the current box and the next box on the waypoint. | ||
+ | * If NPC is finally shortly at arriving at Lara, try to predict the direction in which Lara is running (with different lookahead distances for different types of NPCs). | ||
+ | * Perform an attack based on aforementioned calculations. | ||
{{anchor: | {{anchor: | ||
===== AI Objects ===== | ===== AI Objects ===== | ||
- | Since TR3, in addition to pathfinding data structures, there are now special //AI objects//, which are used in a waypoint-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 // | + | 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 // |
- | > **Note** | + | <note> |
- | > | + | Not every NPC is “taught” to work with AI objects — usually, |
- | > Not every NPC is “taught” to work with AI objects — usually, | + | </ |
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. | + | </ |
{{: | {{: | ||
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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 | + | Beginning with TR4, AI objects are //not kept along with other entities//. Instead, they have their own structure, which is basically |
The format of AI object structure as follows: | The format of AI object structure as follows: |