Mapwad: A High-Level Language for 3D Maze Generation in Quake

1. Project Overview Mapwad: A Maze Generation language Team: Ben Smith, Avrum Tilman, Josh Weinberg, Ron Weiss

2. Overview and Summary • A high level language for creating mazes rendered in 3 dimensions using Quake. • Built in data structures and functions to naturally express a map. • Ability to define custom functions to ease implementation of maps • Java/C style syntax and semantics

3. Motivation

4. Motivation • Designing mazes by hand is tedious and error prone • Build large, complex mazes algorithmically

5. Goals • Easy to use - intuitive syntax, simple language constructs • Flexible - few constraints on maze - walls can be at any angle to each other, etc. • Concise - able to generate complex maze with few lines of code

6. Language Design • The language is designed around high-level data types that offer an intuitive description of a map • Instead of dealing with planes you deal with rooms • Mapwad eliminates the need to specify coordinates • All objects are positioned relative to each other

7. Mapwad syntax • Java/C • Whitespace ignored • Comments /**/ and // • Blocks enclosed in {} • Function default parameters: • MyFunc(int a,int b=3,int c=4) {…} • MyFunc(1,,10); • MyFunc(1,2); • “dot” operator (built-in types only): • myRoom.Walls[0].Length = 10;

8. Reserved Words • Control Flow • if, else, for, while, break, continue, return • Primitive Data Types • int, float, boolean, string • Values • true, false, null

9. Object Data Types • Room • Walls - Super Data Structure • Wall • Location • Thing

10. Built in • Functions • boolean Add(Room r, Wall newWall) • boolean AddAfter(Wall w, Wall newWall) • Remove(Wall w) • boolean Attach(Wall a, Wall b, string connectpoint) • boolean Close(Room r) • boolean IsClosed(Room r) • Math Functions • Variables • MapStart <Location> • MapHeight <float> • CeilingTexture <string> • FloorTexture <string>

11. Semantics • Scoping rules • Global scope • {} blocks have own scope • Rooms and Things automatically added to map • Primitive Types • Passed by value • Instantiated when variable is created • int x; //creates a variable and instantiates an int • Object types • Passed by reference • Object-typed variables are references • Must be explicitly instantiated • Room r; //creates a reference to a Room • r = Room(); //instantiates a Room object

12. Compiler Components • Lexer/Parser • Tree Walker • Walks the AST generated by the parser • Checks types, resolves symbols, etc. • Executes the code • Internal package • Contains code called by the tree walker to manipulate Mapwad structures • Code generator • Creates Quake .map file - text file containing information about contents of map. • QBSP • Compiles .map file into Quake .bsp map file that the game understands.

13. MapwadParser MapwadLexer MapwadWalker Mapwad Builtin Functions qbsp MWGui MWMap Block Diagram

14. Sample Code //creates a regular polygon shaped room Room regularRoom(int walls, float length, string texture="BRICKA2_2") { Room newRoom = Room(); float angle = 180*(walls-2)/walls; int i; for(i=0;i < walls;i++) { Wall w = Wall(length,angle,"",texture); Add(newRoom, w); } Close(newRoom); return newRoom; } Map() { Room r = regularRoom(10, 15, "BRICKA2_4"); Room start = regularRoom(4, 5); Attach(r.Walls[0], start.Walls[0]); Thing t = Thing("monster_army", Location(r.Walls[5], "center", 10)); MapStart = Location(start.Walls[3], "center", 2); CeilingTexture = "sky1"; }

15. Compiler Output "sounds" "1" "classname" "worldspawn" "wad" "quake101.wad" "worldtype" "0" { ( 0 0 0 ) ( 100 0 0 ) ( 0 0 1 ) BRICKA2_4 0 0 0 1.0 1.0 ( 0 -1 0 ) ( 0 -1 1 ) ( 100 -1 0 ) BRICKA2_4 0 0 0 1.0 1.0 ( 0 0 0 ) ( 0 0 1 ) ( 0 -1 0 ) BRICKA2_4 0 0 0 1.0 1.0 ( 100 0 0 ) ( 100 -1 0 ) ( 100 0 1 ) BRICKA2_4 0 0 0 1.0 1.0 ( 0 0 0 ) ( 1 0 0 ) ( 0 1 0 ) BRICKA2_4 0 0 0 1.0 1.0 ( 0 0 100 ) ( 0 1 100 ) ( 1 0 100 ) BRICKA2_4 0 0 0 1.0 1.0 } { ( 100 0 0 ) ( 181 59 0 ) ( 100 0 1 ) BRICKA2_4 0 0 0 1.0 1.0 ( 101 -1 0 ) ( 101 -1 1 ) ( 181 58 0 ) BRICKA2_4 0 0 0 1.0 1.0 …

16. What does it look like?

17. Error Checking There are three types of error checking in Mapwad • Syntax Error • Caught by the lexer/parser • Semantic Error • Caught by the tree walker • Incorrect types, wrong arguments, etc… • Runtime Error/Warning • Caught during code generation • Invalid Geometry • Locations outside of map

18. Testing • Modular Testing • Each module was tested independently • Regression Testing • Basic test cases were reused as code evolved • Integration Testing • Modules were combined slowly and tested at every stage

19. Lessons Learned • Don’t overextend yourself • Our initial design was too ambitious for a one semester project • Fully define interfaces early • We had to modify all our methods late in development • Generalize your code • When we found problems we they were resolved without major code revisions

20. Future Work • Support more generalized 3D structures • More sophisticated error checking • Support for more interactive objects • Doors, Elevators, Moving platforms • Integrate into a graphical level editor