Construct Vehicle archetype from input file (#2)

* Delete level generation code

* Add nlohmann json as a submodule

* Create Vehicle archetypes from an input file

Unlike madrona_escape_room which procedurally generates an environment, gpudrive
generates an environment from an input map file. This updates level_gen.cpp to
construct Vehicles based on a (currently hardcoded) input file. The Agent
archetype is reused for Vechicles.

* Fix up task graph

Since buttons and doors are no longer being generated, this deletes the nodes
associated with those concepts.

Author: SamanKazemkhani

Diff for: .gitmodules

@@ -1,3 +1,6 @@
 [submodule "external/madrona"]
 	path = external/madrona
 	url = https://github.com/shacklettbp/madrona.git
+[submodule "external/json"]
+	path = external/json
+	url = https://github.com/nlohmann/json.git

Diff for: external/CMakeLists.txt

@@ -1 +1,4 @@
 add_subdirectory("${MADRONA_DIR}" madrona EXCLUDE_FROM_ALL)
+add_subdirectory(nlohmann_json)
+
+

Diff for: src/CMakeLists.txt

@@ -13,6 +13,7 @@ target_link_libraries(mad_escape_cpu_impl
     PUBLIC
         madrona_mw_core
     PRIVATE
+        nlohmann_json::nlohmann_json
         madrona_common
         madrona_mw_physics
         madrona_viz_system

Diff for: src/consts.hpp

@@ -9,8 +9,11 @@ namespace consts {
 // must solve in order to maximize their reward.
 inline constexpr madrona::CountT numRooms = 3;
 
-// Generated levels assume 2 agents
-inline constexpr madrona::CountT numAgents = 2;
+// TODO(samk): This number is specifically derived for
+// tfrecord-00004-of-00150_246.json. Once we move to multiple map files, it will
+// have to be updated.
+inline constexpr madrona::CountT numAgents = 42;
+inline constexpr madrona::CountT numRoadSegments = 4425;
 
 // Maximum number of interactive objects per challenge room. This is needed
 // in order to setup the fixed-size learning tensors appropriately.
@@ -48,8 +51,10 @@ inline constexpr float deltaT = 0.04f;
 inline constexpr float doorSpeed = 30.f;
 
 // Number of physics substeps
-inline constexpr madrona::CountT numPhysicsSubsteps = 4.f;
+inline constexpr madrona::CountT numPhysicsSubsteps = 0.f;
 
+inline constexpr float zDimensionScale = 1;
+inline constexpr float xDimensionScaleRoadSegment = 1;
 }
 
 }