Trains move on tracks to the beat

Small implementation changes in various places, biggest thing is now we're using ranges, which is experimental and will be included for real in C++20.

7 files changed, 159 insertions, 40 deletions

@@ -0,0 +1,25 @@
+#include "direction.h"
+
+vec2s posInDir(vec2s orig, Direction dir)
+{
+  switch (dir)
+  {
+    case Direction::left: return orig - vec2s { 1, 0 };
+    case Direction::right: return orig + vec2s { 1, 0 };
+    case Direction::up: return orig - vec2s { 0, 1 };
+    case Direction::down: return orig + vec2s { 0, 1 };
+    case Direction::none: return orig;
+  }
+}
+
+Direction oppositeDir(Direction dir)
+{
+  switch (dir)
+  {
+    case Direction::left: return Direction::right;
+    case Direction::right: return Direction::left;
+    case Direction::up: return Direction::down;
+    case Direction::down: return Direction::up;
+    case Direction::none: return Direction::none;
+  }
+}
@@ -0,0 +1,18 @@
+#ifndef DIRECTION_H_2B40D968
+#define DIRECTION_H_2B40D968
+
+#include "vector.h"
+
+enum class Direction {
+  none,
+  left,
+  right,
+  up,
+  down
+};
+
+vec2s posInDir(vec2s orig, Direction dir);
+
+Direction oppositeDir(Direction dir);
+
+#endif /* end of include guard: DIRECTION_H_2B40D968 */
@@ -4,6 +4,7 @@
 #include <set>
 #include "vector.h"
 #include "enums.h"
+#include "direction.h"
 
 class Entity {
 public:
@@ -14,6 +15,7 @@ public:
 
   // Grid placement
   vec2s gridPos;
+  Layer layer = Layer::object;
 
   // Movement
   Direction shouldMoveTo = Direction::none;
@@ -35,6 +37,11 @@ public:
 
   bool scheduled = false;
 
+  // Track
+  bool isTrack = false;
+  Direction trackDir1 = Direction::none;
+  Direction trackDir2 = Direction::none;
+
 };
 
 #endif /* end of include guard: ENTITY_H_0D6CB29A */
@@ -8,12 +8,9 @@ enum class ColliderType {
   other
 };
 
-enum class Direction {
-  none,
-  left,
-  right,
-  up,
-  down
+enum class Layer {
+  track,
+  object
 };
 
 #endif /* end of include guard: ENUMS_H_CD0A75E4 */
@@ -5,17 +5,23 @@ class Schedule {
 public:
 
   explicit Schedule(
-    size_t bpm) :
+    double bpm) :
       bpm_(bpm),
-      tick_(60.0 / static_cast<double>(bpm_))
+      bps_(bpm_ / 60.0),
+      tick_(1.0 / bps_)
   {
   }
 
-  size_t getBPM() const
+  double getBPM() const
   {
     return bpm_;
   }
 
+  double getBPS() const
+  {
+    return bps_;
+  }
+
   void accumulate(double dt)
   {
     accum_ += dt;
@@ -26,6 +32,7 @@ public:
     if (accum_ > tick_)
     {
       accum_ -= tick_;
+      beats_++;
 
       return true;
     } else {
@@ -33,11 +40,18 @@ public:
     }
   }
 
+  size_t getBeat() const
+  {
+    return beats_;
+  }
+
 private:
 
-  size_t bpm_;
+  double bpm_;
+  double bps_;
   double tick_;
   double accum_ = 0.0;
+  size_t beats_ = 0;
 
 };
 
@@ -1,5 +1,6 @@
 #include "simulation.h"
 
+#include <range/v3/all.hpp>
 #include "consts.h"
 #include "level.h"
 
@@ -7,6 +8,59 @@ Simulation::Simulation(
   const Level& level) :
     level_(level)
 {
+
+
+  id_type trackId = emplaceEntity();
+  Entity& track = getEntity(trackId);
+  track.size = TILE_SIZE;
+  track.layer = Layer::track;
+  track.isTrack = true;
+  track.trackDir1 = Direction::right;
+  track.trackDir2 = Direction::down;
+  track.colorVal = 130;
+  track.gridPos = vec2s { 6, 1 };
+
+  id_type trackId2 = emplaceEntity();
+  Entity& track2 = getEntity(trackId2);
+  track2.size = TILE_SIZE;
+  track2.layer = Layer::track;
+  track2.isTrack = true;
+  track2.trackDir1 = Direction::right;
+  track2.trackDir2 = Direction::up;
+  track2.colorVal = 130;
+  track2.gridPos = vec2s { 6, 2 };
+
+  id_type trackId3 = emplaceEntity();
+  Entity& track3 = getEntity(trackId3);
+  track3.size = TILE_SIZE;
+  track3.layer = Layer::track;
+  track3.isTrack = true;
+  track3.trackDir1 = Direction::up;
+  track3.trackDir2 = Direction::left;
+  track3.colorVal = 130;
+  track3.gridPos = vec2s { 7, 2 };
+
+  id_type trackId4 = emplaceEntity();
+  Entity& track4 = getEntity(trackId4);
+  track4.size = TILE_SIZE;
+  track4.layer = Layer::track;
+  track4.isTrack = true;
+  track4.trackDir1 = Direction::left;
+  track4.trackDir2 = Direction::down;
+  track4.colorVal = 130;
+  track4.gridPos = vec2s { 7, 1 };
+
+
+  id_type trainId = emplaceEntity();
+  Entity& train = getEntity(trainId);
+  train.size = TILE_SIZE;
+  train.speed = schedule_.getBPS() * 2.0;
+  train.colliderType = ColliderType::train;
+  train.scheduled = true;
+  train.colorVal = 90;
+  train.gridPos = vec2s { 6, 1 };
+  train.moveDir = Direction::left;
+
   id_type player = emplaceEntity();
   Entity& entity = getEntity(player);
   entity.size = TILE_SIZE;
@@ -19,7 +73,7 @@ Simulation::Simulation(
   id_type crateId = emplaceEntity();
   Entity& crate = getEntity(crateId);
   crate.size = TILE_SIZE;
-  crate.speed = static_cast<double>(schedule_.getBPM()) / 30.0;
+  crate.speed = schedule_.getBPS() * 2.0;
   crate.colliderType = ColliderType::crate;
   crate.canBePushedBy.insert(ColliderType::player);
   crate.canBePushedBy.insert(ColliderType::crate);
@@ -29,24 +83,13 @@ Simulation::Simulation(
   id_type crateId2 = emplaceEntity();
   Entity& crate2 = getEntity(crateId2);
   crate2.size = TILE_SIZE;
-  crate2.speed = static_cast<double>(schedule_.getBPM()) / 30.0;
+  crate2.speed = schedule_.getBPS() * 2.0;
   crate2.colliderType = ColliderType::crate;
   crate2.canBePushedBy.insert(ColliderType::player);
   crate2.canBePushedBy.insert(ColliderType::crate);
   crate2.canBePushedBy.insert(ColliderType::train);
   crate2.gridPos = vec2s { 6, 7 };
 
-  id_type trainId = emplaceEntity();
-  Entity& train = getEntity(trainId);
-  train.size = TILE_SIZE;
-  train.speed = static_cast<double>(schedule_.getBPM()) / 30.0;
-  train.colliderType = ColliderType::train;
-  train.scheduled = true;
-  train.colorVal = 90;
-  train.gridPos = vec2s { 6, 1 };
-
-
-
 
   for (id_type id : active_)
   {
@@ -145,7 +188,28 @@ void Simulation::tick(
 
       if (entity.scheduled && !entity.moving)
       {
-        moveEntityOnGrid(id, Direction::down);
+        auto tracks =
+          posCache_.at(entity.gridPos) |
+          ranges::view::transform([&] (id_type id) -> Entity& { return entities_.at(id); }) |
+          ranges::view::filter([&] (Entity& other) { return other.isTrack; });
+
+        if (!ranges::empty(tracks))
+        {
+          Entity& track = ranges::front(tracks);
+
+          Direction dir = Direction::none;
+          Direction from = oppositeDir(entity.moveDir);
+
+          if (from == track.trackDir1)
+          {
+            dir = track.trackDir2;
+          } else if (from == track.trackDir2)
+          {
+            dir = track.trackDir1;
+          }
+
+          moveEntityOnGrid(id, dir);
+        }
       }
     }
   }
@@ -282,7 +346,10 @@ bool Simulation::moveEntityOnGrid(
   }
 
   // Can't move into a space that something else is already moving into.
-  if (!moveToCache_.at(shouldMoveTo).empty())
+  if (!ranges::empty(
+        moveToCache_.at(shouldMoveTo) |
+        ranges::view::transform([&] (id_type id) -> Entity& { return entities_.at(id); }) |
+        ranges::view::filter([&] (Entity& other) { return other.layer == entity.layer; })))
   {
     return false;
   }
@@ -291,6 +358,11 @@ bool Simulation::moveEntityOnGrid(
   {
     Entity& block = entities_.at(blockId);
 
+    if (block.layer != entity.layer)
+    {
+      continue;
+    }
+
     if (!block.moving)
     {
       if (!block.canBePushedBy.count(entity.colliderType))
@@ -334,15 +406,3 @@ bool Simulation::moveEntityOnGrid(
 
   return true;
 }
-
-vec2s Simulation::posInDir(vec2s orig, Direction dir)
-{
-  switch (dir)
-  {
-    case Direction::left: return orig - vec2s { 1, 0 };
-    case Direction::right: return orig + vec2s { 1, 0 };
-    case Direction::up: return orig - vec2s { 0, 1 };
-    case Direction::down: return orig + vec2s { 0, 1 };
-    case Direction::none: return orig;
-  }
-}
@@ -47,8 +47,6 @@ public:
     return level_;
   }
 
-  static vec2s posInDir(vec2s orig, Direction dir);
-
 private:
 
 
@@ -60,7 +58,7 @@ private:
     bool validate = false);
 
   const Level& level_;
-  Schedule schedule_ { 120 };
+  Schedule schedule_ { 90 };
 
   std::vector<Entity> entities_;
   std::deque<id_type> available_;