Intro to AI STRIPS Planning & Applications in Video-games Lecture5-Part1
Upcoming SlideShare
Loading in...5
×
 

Intro to AI STRIPS Planning & Applications in Video-games Lecture5-Part1

on

  • 543 views

This is a short course that aims to provide an introduction to the techniques currently used for the decision making of non-player characters (NPCs) in commercial video games, and show how a simple ...

This is a short course that aims to provide an introduction to the techniques currently used for the decision making of non-player characters (NPCs) in commercial video games, and show how a simple deliberation technique from academic artificial intelligence research can be employed to advance the state-of-the art.

For more information and downloading the supplementary material please use the following links:
http://stavros.lostre.org/2012/05/19/video-games-sapienza-roma-2012/
http://tinyurl.com/AI-NPC-LaSapienza

Statistics

Views

Total Views
543
Views on SlideShare
543
Embed Views
0

Actions

Likes
0
Downloads
7
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

Intro to AI STRIPS Planning & Applications in Video-games Lecture5-Part1 Intro to AI STRIPS Planning & Applications in Video-games Lecture5-Part1 Presentation Transcript

  • Stavros Vassos, University of Athens, Greece stavrosv@di.uoa.gr May 2012INTRODUCTION TO AISTRIPS PLANNING.. and Applications to Video-games!
  • Course overview2  Lecture 1: Game-inspired competitions for AI research, AI decision making for non-player characters in games  Lecture 2: STRIPS planning, state-space search  Lecture 3: Planning Domain Definition Language (PDDL), using an award winning planner to solve Sokoban  Lecture 4: Planning graphs, domain independent heuristics for STRIPS planning  Lecture 5: Employing STRIPS planning in games: SimpleFPS, iThinkUnity3D, SmartWorkersRTS  Lecture 6: Planning beyond STRIPS
  • Course overview3  Lecture 1: Game-inspired competitions for AI research, AI decision making for non-player characters in games  Lecture 2: STRIPS planning, state-space search  Lecture 3: Planning Domain Definition Language (PDDL), using an award winning planner to solve Sokoban  Lecture 4: Planning graphs, domain independent heuristics for STRIPS planning  Lecture 5: Employing STRIPS planning in games: SimpleFPS, iThinkUnity3D, SmartWorkersRTS  Lecture 6: Planning beyond STRIPS
  • SimpleFPS planning benchmark4  Focus on first-person shooter (FPS) games and the non-player characters (NPCs) that act against the human player.  Focus on goal-oriented action planning (GOAP) for NPC behavior.
  • SimpleFPS planning benchmark5  Focus on first-person shooter (FPS) games and the non-player characters (NPCs) that act against the human player.  Focus on goal-oriented action planning (GOAP) for NPC behavior.  SimpleFPS is a first step towards evaluating how the existing academic approaches for planning would perform if directly applied in an FPS setting.
  • SimpleFPS planning benchmark6  Focus on first-person shooter (FPS) games and the non-player characters (NPCs) that act against the human player.  Focus on goal-oriented action planning (GOAP) for NPC behavior.  SimpleFPS is a first step towards evaluating how the existing academic approaches for planning would perform if directly applied in an FPS setting.
  • STRIPS Planning7  Given:  Initial State  Goal  Available actions  Find: A sequence of actions that satisfy the goal  E.g.: [Left, Down, Left, Up, …]
  • Planning Domain Description Language8  Language for specifying STRIPS planning problems  Formal syntax like a programming language  Initial State (:init …)  Goal (:goal …)  Actions (:action name :parameters (?from ?to ?dir) :preconditions (…) :effects (…) )
  • Planning Domain Description Language9  Language for specifying STRIPS planning problems  Formal syntax like a programming language  Initial State (:init …)  Goal (:goal …)  Actions (:action name :parameters (?from ?to ?dir) :preconditions (…) :effects (…) )  Literals like Lisp, e.g., bot-at(area1) (bot-at area1)
  • Planning Domain Description Language10  Language for specifying STRIPS planning problems  Formal syntax like a programming language  Predicates (:predicates …)  Actions (:action name :parameters (?from ?to ?dir) :preconditions (…) Planning :effects (…) Domain )  Objects (:objects …) Planning  Initial State (:init …) Problem  Goal (:goal …)
  • Planning Domain Description Language11  Planning Domain Description Language  SAT Plan Planning Domains in PDDL:  TL Plan Blocks world, Storage, Trucks, …  FF  BlackBox Planning Problems in PDDL for these domains  SHOP2  TALPlanner … Comparisons Evaluation Conclusions
  • Planning Domain Description Language12  Planning Domain Description Language  SAT Plan Planning Domains in PDDL:  TL Plan SimpleFPS Domain  FF  BlackBox Planning Problems in PDDL for SimpleFPS domain  SHOP2  TALPlanner … Comparisons Evaluation Conclusions
  • Motivation for SimpleFPS13  Planning in academia: extensively tested  Planning in FPS video games: not extensively tested  SimpleFPS: A PDDL domain for evaluating academic planning techniques for NPCs in First-Person Shooters
  • Motivation for SimpleFPS14  Planning in academia: extensively tested  Many PDDL planning domains and problems available  Many off-the-shelf PDDL planners available  Planning in FPS video games: not extensively tested A few success stories but not clear if the same works under different assumptions or what is the best approach  SimpleFPS: A PDDL domain for evaluating academic planning techniques for NPCs in First-Person Shooters
  • SimpleFPS planning benchmark15  SimpleFPS_PDDL_Domain.txt  SimpleFPS_PDDL_ProblemGenerator.c
  • SimpleFPS planning benchmark16  SimpleFPS_PDDL_Domain.txt:  Specifies the predicates that can be used to describe the initial state of the game-world and the goal condition for the NPC.  Specifies a list of available actions that the NPC can perform, along with their preconditions and effects in terms of the predicates of the domain.  SimpleFPS_PDDL_ProblemGenerator.c: A tool to generate problem instances, i.e., an initial state of the game-world and a goal for the NPC.
  • SimpleFPS planning benchmark17  Summer student project at the University of Athens  Michail Papakonstantinou  AIIDE-2011 workshop paper  TheSimpleFPS Planning Domain: A PDDL Benchmark for Proactive NPCs  Code/datasets available online  http://code.google.com/p/simple-fps-pddl/
  • SimpleFPS domain18
  • SimpleFPS domain19  Represent only very simple high-level features:  Game-world consists of interconnected areas, each of which has a number of points of interest (POIs). A few types of items located at POIs (weapons, ammo, med-kits, keycards).  NPC can perform basic actions (move between areas or POIs, pick-up/use items, attack, take cover).
  • A SimpleFPS problem instance20  (:init …)
  • A SimpleFPS problem instance21  (:init …) 6 areas, some of them connected through doors a1 a3 and corridors: a2  (area a1)  (area a2) a4  (area a3)  (area a4) a6 a5  (area a5)  (area a6)
  • A SimpleFPS problem instance22  (:init …) 6 areas, some of them connected through doors a1 and corridors: a2  (poi door1 a1)  (waypoint door1)  (connected a1 a2 door1)  (closed door1)  (opens door1 keycard1)
  • A SimpleFPS problem instance23  (:init …)  For each area a number of POIs are listed along with their properties: a2  (poi door1 a2)  (poi c1 a2)  (poi c2 a2)  (connected a2 a1 door1)  (cover-point c1)  (cover-point c2)
  • A SimpleFPS problem instance24  (:init …)  For each area a number of POIs are listed along with their properties:  (poi g1 a5)  (poi amm1 a5)  (gun g1)  (unloaded g1) a5  (ammo amm1 g1)
  • A SimpleFPS problem instance25  (:init …)  For each area a number of POIs are listed along a1 a3 with their properties: a2  knife  med-kit a4  control-box  night-vision-gun a6 a5 …
  • SimpleFPS domain: predicates26  NPC-related  Area-related  Item-related:  (npc-at ?a)  (area ?a)  (med-kit ?m)  (npc-close-to ?p)  (conn ?a1 ?a2 ?w)  (knife ?k)  (npc-covered)  (waypoint ?w)  (gun ?g)  (npc-uncovered)  (lighted ?area)  (loaded ?g)  (npc-holding ?o)  (dark ?area)  (unloaded ?g)  (npc-injured)  (poi ?p ?a)  (ammo ?i ?g)  (npc-full-health)  (control-box ?p)  (night-vision ?g)  (npc-aware)  (cover-point ?p)  (npc-unaware)  (item ?p)
  • SimpleFPS domain: actions27  (: action …)  Available NPC actions: a1 a3  move-to-area a2  move-to-poi  pick-up-item  use-item a4  take-cover a6 a5  un-cover
  • SimpleFPS domain: move-to-point28 (:action move-to-point :parameters (?area ?point) :precondition (and (npc-at ?area) (point-of-interest ?point ?area) ) :effect (and (npc-close-to ?point) ) )
  • SimpleFPS domain: reload29 (:action reload :parameters (?gun ?item) :precondition (and (npc-holding ?gun) (gun ?gun) (unloaded ?gun) (npc-holding ?item) (ammo ?item ?gun) ) :effect (and (not (unloaded ?gun)) (loaded ?gun) (not (npc-holding ?item)) ) )
  • The SimpleFPS domain: actions30  Location-related:  Attack-related:  moving-to-patrol  make-contact  moving-to-take-position  take-cover  move-away-from-point  uncover  move-to-point  use-med-kit  move-to-point-from-point  reload  make-accessible  attack-melee  place-in-inventory  attack-ranged  turn-on-lights  sneak-kill  turn-off-lights
  • A SimpleFPS problem instance31  (:goal …)  NPC goals: a1 a3  g1: (player-wounded) a2  g2: (npc-covered)  g3: (npc-full-health) a4  g4: (and g1 g2 g3) a6 a5
  • A SimpleFPS problem instance32  blackbox -o problemssfps-domain.txt -f problemssfps-problem1.txt  1. (move-to-point area3 door3-2)  2. (move-to-point area2 control-box2)  3. (turn-on-lights area2 control-box2)  4. (make-contact area2 p)  5. (move-to-point-from-point area2 knife2 control-box2)  6. (place-in-inventory area2 knife2)  7. (move-to-point area2 p)  8. (attack-melee area2 knife2 p)  9. (move-to-point-from-point area2 door2-0 p)  10. (moving-to-take-position area2 area0 door2-0)  11. (move-to-point area0 coverpoint1)  12. (take-cover area0 coverpoint1)
  • SimpleFPS problem generator33
  • SimpleFPS problem generator34  Takes as input:  -a number of areas,  -c the probability that two areas are connected  -n total number of points of interest  -g the goal condition as one of g1, g2, g3, g4  -l the number of instances to be generated  Generates problem instances also using some rules:  Card-keysare added for locked doors  Ammo is added for guns that are unloaded …
  • SimpleFPS datasets35  Used the tool to generate 3 datasets: 5 areas  7 areas  10 areas  For each dataset we generated 10 instances with:  10 items …  100 items  For each of the 4 goals:  g1, g2, g3, g4
  • Preliminary results with SimpleFPS36  Used two award-winning planners in these datasets:  BlackBox [Kauts, Selman 1999]  FastForward [Hoffman 2001]  Run the planners on an average laptop  1.4GHz  2 GB RAM
  • Preliminary results with SimpleFPS37  BlackBox, FastForward  Problems planners always return an answer within 1.5sec BB: up to 5 areas/50 POIs FF: up to 10 areas/70 POIs
  • Preliminary results with SimpleFPS38  BlackBox,Different planning techniques paper FastForward: Two graphs in the  Problems planners a lot of difference within 1.5sec make always return an answer BB: up to 5 areas/50 POIs FF: up to 10 areas/70 POIs
  • Preliminary results with SimpleFPS39  Investigate further the available heuristics for progression planning using FastDownward as a framework
  • Thorough results with SimpleFPS40  Left: best-first search with FF heuristic  Right: weighted A* search with a combination of FF and landmark cut heuristic  Average (total) run-time of planner
  • Thorough results with SimpleFPS41  Left: best-first search with FF heuristic  Right: weighted A* search with a combination of FF and landmark cut heuristic  Average (total) run-time of planner
  • Thorough results with SimpleFPS42  Left: best-first search with FF heuristic  Right: weighted A* search with a combination of FF and landmark cut heuristic  Average run-time of planner doing search
  • Thorough results with SimpleFPS43  Left: best-first search with FF heuristic  Right: weighted A* search with a combination of FF and landmark cut heuristic  Average run-time of planner doing search
  • Thorough results with SimpleFPS44  Left: best-first search with FF heuristic  Right: weighted A* search with a combination of FF and landmark cut heuristic  Average plan length
  • Thorough results with SimpleFPS45  Left: best-first search with FF heuristic  Right: weighted A* search with a combination of FF and landmark cut heuristic  Average plan length
  • Some conclusions46
  • Some conclusions47  Relatively small-sized problems wrt FPS games:  10 areas/100 POIs  The planner takes a lot of resources: A lot of time: up to 1.4 sec to respond using 100% of the CPU resources of a laptop  A lot of memory: up to 6.5MB for each problem
  • Some conclusions48  Relatively small-sized problems wrt FPS games:  10 areas/100 POIs  The planner takes a lot of resources: A lot of time: up to 1.4 sec to respond using 100% of the CPU resources of a laptop  A lot of memory: up to 6.5MB for each problem  Different assumptions in academia and FPS games
  • Some conclusions49  There is a lot of room for improvement  Take advantage of pre-processing  6.5 MBs is too much for 1 character but how about 100?  Maintain the pre-processed state and update instead of re-computing it each time  Guide the search method  The Golog family of languages
  • Bibliography50  References  The SimpleFPS Planning Domain: A PDDL Benchmark for Proactive NPCs. Stavros Vassos, Michail Papakonstantinou. In Proceedings of the Non- Player Character AI workshop (NPCAI-2011), 2011  PDDL - The Planning Domain Definition Language. Drew McDermott, Malik Ghallab, Adele Howe, Craig Knoblock, Ashwin Ram, Manuela Veloso, Daniel Weld, David Wilkins. Technical report, Yale Center for Computational Vision and Control, TR-98-003, 1998.  Unifying SAT-Based and Graph-Based Planning. Henry Kautz, Bart Selman. In Proceedings of the International Joint Conference on Artificial Intelligence (IJCAI), 1999  The FF planning system: Fast plan generation through heuristic search. Jörg Hoffmann, Bernhard Nebel. Artificial Intelligence Research, Vol. 14, 2001  The Fast Downward Planning System. Malte Helmert. Artificial Intelligence Research (JAIR), Vol. 26, 2006