From 3504fd5080dbcfd0172299c5c6d13895e53ad163 Mon Sep 17 00:00:00 2001
From: Kelly Rauchenberger <fefferburbia@gmail.com>
Date: Sat, 23 Feb 2019 12:15:46 -0500
Subject: Removed position caches

There aren't going to be enough entities at once for position checking to ever really be a bottleneck, I don't think. Removing the caches makes the range logic a bit more intuitive, and it removes the possibility of accidentally not updating a cache when it needs to be.
---
 src/grid_cache.h   | 59 ------------------------------------------------------
 src/simulation.cpp | 22 ++++++++------------
 src/simulation.h   |  4 ----
 src/vector.h       |  5 +++++
 src/views.h        | 14 +++++++++++++
 5 files changed, 27 insertions(+), 77 deletions(-)
 delete mode 100644 src/grid_cache.h

diff --git a/src/grid_cache.h b/src/grid_cache.h
deleted file mode 100644
index e837f55..0000000
--- a/src/grid_cache.h
+++ /dev/null
@@ -1,59 +0,0 @@
-#ifndef GRID_CACHE_H_67BBE74D
-#define GRID_CACHE_H_67BBE74D
-
-#include <unordered_map>
-#include <unordered_set>
-#include "level.h"
-
-template <typename T>
-class GridCache {
-public:
-
-  explicit GridCache(const Level& level) : width_(level.getSize().w())
-  {
-  }
-
-  void set(T value, vec2s pos)
-  {
-    if (reverse_.count(value))
-    {
-      size_t oldPosIndex = reverse_.at(value);
-      lookup_[oldPosIndex].erase(value);
-    }
-
-    size_t newPosIndex = getIndex(pos);
-    lookup_[newPosIndex].insert(value);
-    reverse_[value] = newPosIndex;
-  }
-
-  void remove(T value)
-  {
-    if (reverse_.count(value))
-    {
-      size_t index = reverse_.at(value);
-      lookup_[index].erase(value);
-      reverse_.erase(value);
-    }
-  }
-
-  const std::unordered_set<T>& at(vec2s pos) const
-  {
-    size_t index = getIndex(pos);
-
-    return lookup_[index];
-  }
-
-private:
-
-  inline size_t getIndex(const vec2s& pos) const
-  {
-    return pos.x() + pos.y() * width_;
-  }
-
-  size_t width_;
-
-  mutable std::unordered_map<size_t, std::unordered_set<T>> lookup_;
-  std::unordered_map<T, size_t> reverse_;
-};
-
-#endif /* end of include guard: GRID_CACHE_H_67BBE74D */
diff --git a/src/simulation.cpp b/src/simulation.cpp
index f75bd3d..27ac6ab 100644
--- a/src/simulation.cpp
+++ b/src/simulation.cpp
@@ -89,12 +89,6 @@ Simulation::Simulation(
   crate2.canBePushedBy.insert(ColliderType::crate);
   crate2.canBePushedBy.insert(ColliderType::train);
   crate2.gridPos = vec2s { 6, 7 };
-
-
-  for (Entity& entity : active_ | entityView())
-  {
-    posCache_.set(entity.id, entity.gridPos);
-  }
 }
 
 void Simulation::tick(
@@ -132,8 +126,9 @@ void Simulation::tick(
       vec2s lookPos = posInDir(entity.gridPos, lookDir);
 
       for (Entity& block :
-            posCache_.at(lookPos) |
+            active_ |
             entityView() |
+            views::atGridPos(lookPos) |
             views::isNotMoving() |
             views::canBePushedBy(entity.colliderType) |
             views::isOnLayer(entity.layer))
@@ -185,8 +180,9 @@ void Simulation::tick(
           views::isNotMoving())
     {
       auto tracks =
-        posCache_.at(entity.gridPos) |
+        active_ |
         entityView() |
+        views::atGridPos(entity.gridPos) |
         views::isTrack();
 
       if (!ranges::empty(tracks))
@@ -233,8 +229,6 @@ void Simulation::tick(
       {
         entity.moving = false;
         entity.gridPos = entity.destPos;
-        posCache_.set(entity.id, entity.gridPos);
-        moveToCache_.remove(entity.id);
       }
     }
 
@@ -340,16 +334,18 @@ bool Simulation::moveEntityOnGrid(
 
   // Can't move into a space that something else is already moving into.
   if (!ranges::empty(
-        moveToCache_.at(shouldMoveTo) |
+        active_ |
         entityView() |
+        views::isMovingTo(shouldMoveTo) |
         views::isOnLayer(entity.layer)))
   {
     return false;
   }
 
   for (Entity& block :
-        posCache_.at(shouldMoveTo) |
+        active_ |
         entityView() |
+        views::atGridPos(shouldMoveTo) |
         views::isOnLayer(entity.layer))
   {
     if (!block.moving)
@@ -389,8 +385,6 @@ bool Simulation::moveEntityOnGrid(
     entity.destPos = shouldMoveTo;
     entity.movementTween = 0.0;
     entity.moveDir = moveDir;
-
-    moveToCache_.set(entity.id, entity.destPos);
   }
 
   return true;
diff --git a/src/simulation.h b/src/simulation.h
index a205796..096377c 100644
--- a/src/simulation.h
+++ b/src/simulation.h
@@ -4,7 +4,6 @@
 #include "entity.h"
 #include "renderer.h"
 #include "schedule.h"
-#include "grid_cache.h"
 #include <range/v3/all.hpp>
 #include <vector>
 #include <deque>
@@ -76,9 +75,6 @@ private:
   std::vector<Entity> entities_;
   std::deque<id_type> available_;
   std::set<id_type> active_;
-
-  mutable GridCache<id_type> posCache_ { level_ };
-  mutable GridCache<id_type> moveToCache_ { level_ };
 };
 
 #endif /* end of include guard: SIMULATION_H_7BF6EEA4 */
diff --git a/src/vector.h b/src/vector.h
index 10fe4da..a94aea0 100644
--- a/src/vector.h
+++ b/src/vector.h
@@ -112,6 +112,11 @@ public:
     return vec2(x() * other.x(), y() * other.y());
   }
 
+  constexpr bool operator==(const vec2& other) const
+  {
+    return (x() == other.x()) && (y() == other.y());
+  }
+
 };
 
 using vec2s = vec2<size_t>;
diff --git a/src/views.h b/src/views.h
index 69bd2b5..540dc52 100644
--- a/src/views.h
+++ b/src/views.h
@@ -55,6 +55,20 @@ namespace views {
     });
   }
 
+  inline auto atGridPos(vec2s pos)
+  {
+    return ranges::view::filter([pos] (const Entity& entity) {
+      return entity.gridPos == pos;
+    });
+  }
+
+  inline auto isMovingTo(vec2s pos)
+  {
+    return ranges::view::filter([pos] (const Entity& entity) {
+      return entity.moving && entity.destPos == pos;
+    });
+  }
+
 
 
 }
-- 
cgit 1.4.1