Add camera entity (#120)

Author: aaravpandya

Diff for: src/level_gen.cpp

@@ -315,8 +315,27 @@ void createPaddingEntities(Engine &ctx) {
     }
 }
 
+void createCameraEntity(Engine &ctx)
+{
+    auto camera = ctx.makeRenderableEntity<CameraAgent>();
+    ctx.get<Position>(camera) = Vector3{.x = 0, .y = 0, .z = 20};
+    ctx.get<Rotation>(camera) = (math::Quat::angleAxis(0, math::up) *
+            math::Quat::angleAxis(-math::pi / 2.f, math::right)).normalize();
+
+    render::RenderingSystem::attachEntityToView(ctx,
+        camera,
+        150.f, 0.001f,
+        1.5f * math::up);
+}
+
 void createPersistentEntities(Engine &ctx, Map *map) {
     // createFloorPlane(ctx);
+
+    if (ctx.data().enableRender)
+    {
+        createCameraEntity(ctx);
+    }
+
     ctx.data().mean = {0, 0};
     ctx.data().mean.x = map->mean.x;
     ctx.data().mean.y = map->mean.y;

Diff for: src/mgr.cpp

@@ -81,7 +81,7 @@ static inline Optional<render::RenderManager> initRenderManager(
         .agentViewWidth = mgr_cfg.batchRenderViewWidth,
         .agentViewHeight = mgr_cfg.batchRenderViewHeight,
         .numWorlds = mgr_cfg.numWorlds,
-        .maxViewsPerWorld = consts::kMaxAgentCount, // FIXME?
+        .maxViewsPerWorld = consts::kMaxAgentCount + 1, // FIXME?
         .maxInstancesPerWorld = 3000,
         .execMode = mgr_cfg.execMode,
         .voxelCfg = {},

Diff for: src/sim.cpp

@@ -55,6 +55,7 @@ void Sim::registerTypes(ECSRegistry &registry, const Config &cfg)
 
     registry.registerArchetype<Agent>();
     registry.registerArchetype<PhysicsEntity>();
+    registry.registerArchetype<CameraAgent>();
 
     registry.exportSingleton<WorldReset>(
         (uint32_t)ExportID::Reset);

Diff for: src/types.hpp

@@ -217,6 +217,13 @@ static_assert(sizeof(AbsoluteSelfObservation) == sizeof(float) * AbsoluteSelfObs
 
 /* ECS Archetypes for the game */
 
+struct CameraAgent : public madrona::Archetype<
+    Position,
+    Rotation,
+    madrona::render::RenderCamera,
+    madrona::render::Renderable
+> {};
+
 // There are 2 Agents in the environment trying to get to the destination
 struct Agent : public madrona::Archetype<
     // Basic components required for physics. Note that the current physics