10 files changed, 951 insertions, 0 deletions

@@ -0,0 +1,68 @@
+#include "animating.h"
+#include "game.h"
+#include "components/animatable.h"
+#include "components/transformable.h"
+
+void AnimatingSystem::tick(double)
+{
+  std::set<id_type> spriteEntities =
+    game_.getEntityManager().getEntitiesWithComponents<AnimatableComponent>();
+
+  for (id_type entity : spriteEntities)
+  {
+    auto& sprite = game_.getEntityManager().
+      getComponent<AnimatableComponent>(entity);
+
+    sprite.setCountdown(sprite.getCountdown() + 1);
+
+    const Animation& anim = sprite.getAnimation();
+    if (sprite.getCountdown() >= anim.getDelay())
+    {
+      sprite.setFrame(sprite.getFrame() + 1);
+      sprite.setCountdown(0);
+
+      if (sprite.getFrame() >= anim.getFirstFrame() + anim.getNumFrames())
+      {
+        sprite.setFrame(anim.getFirstFrame());
+      }
+    }
+  }
+}
+
+void AnimatingSystem::render(Texture& texture)
+{
+  std::set<id_type> spriteEntities =
+    game_.getEntityManager().getEntitiesWithComponents<
+      AnimatableComponent,
+      TransformableComponent>();
+
+  for (id_type entity : spriteEntities)
+  {
+    auto& sprite = game_.getEntityManager().
+      getComponent<AnimatableComponent>(entity);
+
+    auto& transform = game_.getEntityManager().
+      getComponent<TransformableComponent>(entity);
+
+    Rectangle dstrect {
+      static_cast<int>(transform.getX()),
+      static_cast<int>(transform.getY()),
+      transform.getW(),
+      transform.getH()};
+
+    const AnimationSet& aset = sprite.getAnimationSet();
+    texture.blit(
+      aset.getTexture(),
+      aset.getFrameRect(sprite.getFrame()),
+      dstrect);
+  }
+}
+
+void AnimatingSystem::startAnimation(id_type entity, std::string animation)
+{
+  auto& sprite = game_.getEntityManager().
+    getComponent<AnimatableComponent>(entity);
+
+  sprite.setAnimation(animation);
+  sprite.setFrame(sprite.getAnimation().getFirstFrame());
+}
@@ -0,0 +1,23 @@
+#ifndef ANIMATING_H_5BBF0094
+#define ANIMATING_H_5BBF0094
+
+#include "system.h"
+#include <string>
+#include "renderer.h"
+
+class AnimatingSystem : public System {
+public:
+
+  AnimatingSystem(Game& game) : System(game)
+  {
+  }
+
+  void tick(double dt);
+
+  void render(Texture& texture);
+
+  void startAnimation(id_type entity, std::string animation);
+
+};
+
+#endif /* end of include guard: ANIMATING_H_5BBF0094 */
@@ -0,0 +1,107 @@
+#include "controlling.h"
+#include "game.h"
+#include "components/controllable.h"
+#include "components/orientable.h"
+#include "systems/orienting.h"
+
+void ControllingSystem::tick(double)
+{
+  while (!actions_.empty())
+  {
+    int key = actions_.front().first;
+    int action = actions_.front().second;
+
+    auto entities = game_.getEntityManager().getEntitiesWithComponents<
+      ControllableComponent,
+      OrientableComponent>();
+
+    for (auto entity : entities)
+    {
+      auto& controllable = game_.getEntityManager().
+        getComponent<ControllableComponent>(entity);
+
+      auto& orienting = game_.getSystemManager().getSystem<OrientingSystem>();
+
+      if (action == GLFW_PRESS)
+      {
+        if (key == controllable.getLeftKey())
+        {
+          controllable.setHoldingLeft(true);
+
+          if (!controllable.isFrozen())
+          {
+            orienting.moveLeft(entity);
+          }
+        } else if (key == controllable.getRightKey())
+        {
+          controllable.setHoldingRight(true);
+
+          if (!controllable.isFrozen())
+          {
+            orienting.moveRight(entity);
+          }
+        } else if (key == controllable.getJumpKey())
+        {
+          if (!controllable.isFrozen())
+          {
+            orienting.jump(entity);
+          }
+        } else if (key == controllable.getDropKey())
+        {
+          if (!controllable.isFrozen())
+          {
+            orienting.drop(entity);
+          }
+        }
+      } else if (action == GLFW_RELEASE)
+      {
+        if (key == controllable.getLeftKey())
+        {
+          controllable.setHoldingLeft(false);
+
+          if (!controllable.isFrozen())
+          {
+            if (controllable.isHoldingRight())
+            {
+              orienting.moveRight(entity);
+            } else {
+              orienting.stopWalking(entity);
+            }
+          }
+        } else if (key == controllable.getRightKey())
+        {
+          controllable.setHoldingRight(false);
+
+          if (!controllable.isFrozen())
+          {
+            if (controllable.isHoldingLeft())
+            {
+              orienting.moveLeft(entity);
+            } else {
+              orienting.stopWalking(entity);
+            }
+          }
+        } else if (key == controllable.getDropKey())
+        {
+          if (!controllable.isFrozen())
+          {
+            orienting.stopDropping(entity);
+          }
+        } else if (key == controllable.getJumpKey())
+        {
+          if (!controllable.isFrozen())
+          {
+            orienting.stopJumping(entity);
+          }
+        }
+      }
+    }
+
+    actions_.pop();
+  }
+}
+
+void ControllingSystem::input(int key, int action)
+{
+  actions_.push(std::make_pair(key, action));
+}
@@ -0,0 +1,22 @@
+#ifndef CONTROLLING_H_80B1BB8D
+#define CONTROLLING_H_80B1BB8D
+
+#include "system.h"
+#include <queue>
+
+class ControllingSystem : public System {
+public:
+
+  ControllingSystem(Game& game) : System(game)
+  {
+  }
+
+  void tick(double dt);
+  void input(int key, int action);
+
+private:
+
+  std::queue<std::pair<int,int>> actions_;
+};
+
+#endif /* end of include guard: CONTROLLING_H_80B1BB8D */
@@ -0,0 +1,141 @@
+#include "mapping.h"
+#include "components/mappable.h"
+#include "game.h"
+#include "consts.h"
+
+template <typename Storage>
+inline void addBoundary(
+  Storage& boundaries,
+  int axis,
+  int lower,
+  int upper,
+  MappableComponent::Boundary::Type type)
+{
+  boundaries.emplace(std::piecewise_construct,
+    std::tie(axis),
+    std::tie(axis, lower, upper, type));
+}
+
+void MappingSystem::render(Texture& texture)
+{
+  auto entities = game_.getEntityManager().getEntitiesWithComponents<
+    MappableComponent>();
+
+  for (id_type entity : entities)
+  {
+    auto& mappable = game_.getEntityManager().
+      getComponent<MappableComponent>(entity);
+
+    const Map& map = game_.getWorld().getMap(mappable.getMapId());
+
+    for (int i = 0; i < MAP_WIDTH * MAP_HEIGHT; i++)
+    {
+      int x = i % MAP_WIDTH;
+      int y = i / MAP_WIDTH;
+      int tile = map.getTiles()[i];
+
+      if (tile > 0)
+      {
+        Rectangle dst {
+          x * TILE_WIDTH,
+          y * TILE_HEIGHT,
+          TILE_WIDTH,
+          TILE_HEIGHT};
+
+        Rectangle src {
+          (tile % TILESET_COLS) * TILE_WIDTH,
+          (tile / TILESET_COLS) * TILE_HEIGHT,
+          TILE_WIDTH,
+          TILE_HEIGHT};
+
+        texture.blit(mappable.getTileset(), std::move(src), std::move(dst));
+      }
+    }
+
+    int startX = ((GAME_WIDTH / TILE_WIDTH) / 2) - (map.getTitle().size() / 2);
+    for (size_t i = 0; i < map.getTitle().size(); i++)
+    {
+      Rectangle src {
+        (map.getTitle()[i] % FONT_COLS) * TILE_WIDTH,
+        (map.getTitle()[i] / FONT_COLS) * TILE_HEIGHT,
+        TILE_WIDTH,
+        TILE_HEIGHT};
+
+      Rectangle dst {
+        (startX + static_cast<int>(i)) * TILE_WIDTH,
+        24 * TILE_HEIGHT,
+        TILE_WIDTH,
+        TILE_HEIGHT};
+
+      texture.blit(mappable.getFont(), std::move(src), std::move(dst));
+    }
+  }
+}
+
+void MappingSystem::loadMap(size_t mapId)
+{
+  id_type mapEntity = game_.getEntityManager().emplaceEntity();
+
+  auto& mappable = game_.getEntityManager().
+    emplaceComponent<MappableComponent>(mapEntity,
+      Texture("res/tiles.png"),
+      Texture("res/font.bmp"));
+
+  mappable.setMapId(mapId);
+
+  const Map& map = game_.getWorld().getMap(mappable.getMapId());
+
+  for (size_t i = 0; i < MAP_WIDTH * MAP_HEIGHT; i++)
+  {
+    size_t x = i % MAP_WIDTH;
+    size_t y = i / MAP_WIDTH;
+    int tile = map.getTiles()[i];
+
+    if ((tile >= 5) && (tile <= 7))
+    {
+      addBoundary(
+        mappable.getDownBoundaries(),
+        y * TILE_HEIGHT,
+        x * TILE_WIDTH,
+        (x + 1) * TILE_WIDTH,
+        MappableComponent::Boundary::Type::platform);
+    } else if ((tile > 0) && (tile < 28))
+    {
+      addBoundary(
+        mappable.getRightBoundaries(),
+        x * TILE_WIDTH,
+        y * TILE_HEIGHT,
+        (y+1) * TILE_HEIGHT,
+        MappableComponent::Boundary::Type::wall);
+
+      addBoundary(
+        mappable.getLeftBoundaries(),
+        (x+1) * TILE_WIDTH,
+        y * TILE_HEIGHT,
+        (y+1) * TILE_HEIGHT,
+        MappableComponent::Boundary::Type::wall);
+
+      addBoundary(
+        mappable.getDownBoundaries(),
+        y * TILE_HEIGHT,
+        x * TILE_WIDTH,
+        (x+1) * TILE_WIDTH,
+        MappableComponent::Boundary::Type::wall);
+
+      addBoundary(
+        mappable.getUpBoundaries(),
+        (y+1) * TILE_HEIGHT,
+        x * TILE_WIDTH,
+        (x+1) * TILE_WIDTH,
+        MappableComponent::Boundary::Type::wall);
+    } else if (tile == 42)
+    {
+      addBoundary(
+        mappable.getDownBoundaries(),
+        y * TILE_HEIGHT,
+        x * TILE_WIDTH,
+        (x+1) * TILE_WIDTH,
+        MappableComponent::Boundary::Type::danger);
+    }
+  }
+}
@@ -0,0 +1,19 @@
+#ifndef MAPPING_H_33FC2294
+#define MAPPING_H_33FC2294
+
+#include "system.h"
+
+class MappingSystem : public System {
+public:
+
+  MappingSystem(Game& game) : System(game)
+  {
+  }
+
+  void render(Texture& texture);
+
+  void loadMap(size_t mapId);
+
+};
+
+#endif /* end of include guard: MAPPING_H_33FC2294 */
@@ -0,0 +1,236 @@
+#include "orienting.h"
+#include "game.h"
+#include "components/orientable.h"
+#include "components/ponderable.h"
+#include "systems/animating.h"
+#include "consts.h"
+#include "muxer.h"
+
+void OrientingSystem::tick(double)
+{
+  auto entities = game_.getEntityManager().getEntitiesWithComponents<
+    OrientableComponent,
+    PonderableComponent>();
+
+  for (id_type entity : entities)
+  {
+    auto& orientable = game_.getEntityManager().
+      getComponent<OrientableComponent>(entity);
+
+    auto& ponderable = game_.getEntityManager().
+      getComponent<PonderableComponent>(entity);
+
+    switch (orientable.getWalkState())
+    {
+      case OrientableComponent::WalkState::still:
+      {
+        ponderable.setVelocityX(0);
+
+        break;
+      }
+
+      case OrientableComponent::WalkState::left:
+      {
+        ponderable.setVelocityX(-WALK_SPEED);
+
+        break;
+      }
+
+      case OrientableComponent::WalkState::right:
+      {
+        ponderable.setVelocityX(WALK_SPEED);
+
+        break;
+      }
+    }
+
+    if (orientable.isJumping() && (ponderable.getVelocityY() > 0))
+    {
+      orientable.setJumping(false);
+    }
+  }
+}
+
+void OrientingSystem::moveLeft(id_type entity)
+{
+  auto& ponderable = game_.getEntityManager().
+    getComponent<PonderableComponent>(entity);
+
+  auto& orientable = game_.getEntityManager().
+    getComponent<OrientableComponent>(entity);
+
+  orientable.setFacingRight(false);
+  orientable.setWalkState(OrientableComponent::WalkState::left);
+
+  auto& animating = game_.getSystemManager().getSystem<AnimatingSystem>();
+  if (ponderable.isGrounded())
+  {
+    animating.startAnimation(entity, "walkingLeft");
+  } else {
+    animating.startAnimation(entity, "stillLeft");
+  }
+}
+
+void OrientingSystem::moveRight(id_type entity)
+{
+  auto& ponderable = game_.getEntityManager().
+    getComponent<PonderableComponent>(entity);
+
+  auto& orientable = game_.getEntityManager().
+    getComponent<OrientableComponent>(entity);
+
+  orientable.setFacingRight(true);
+  orientable.setWalkState(OrientableComponent::WalkState::right);
+
+  auto& animating = game_.getSystemManager().getSystem<AnimatingSystem>();
+  if (ponderable.isGrounded())
+  {
+    animating.startAnimation(entity, "walkingRight");
+  } else {
+    animating.startAnimation(entity, "stillRight");
+  }
+}
+
+void OrientingSystem::stopWalking(id_type entity)
+{
+  auto& ponderable = game_.getEntityManager().
+    getComponent<PonderableComponent>(entity);
+
+  auto& orientable = game_.getEntityManager().
+    getComponent<OrientableComponent>(entity);
+
+  orientable.setWalkState(OrientableComponent::WalkState::still);
+
+  if (ponderable.isGrounded())
+  {
+    auto& animating = game_.getSystemManager().getSystem<AnimatingSystem>();
+
+    if (orientable.isFacingRight())
+    {
+      animating.startAnimation(entity, "stillRight");
+    } else {
+      animating.startAnimation(entity, "stillLeft");
+    }
+  }
+}
+
+void OrientingSystem::jump(id_type entity)
+{
+  auto& ponderable = game_.getEntityManager().
+    getComponent<PonderableComponent>(entity);
+
+  if (ponderable.isGrounded())
+  {
+    auto& orientable = game_.getEntityManager().
+      getComponent<OrientableComponent>(entity);
+
+    orientable.setJumping(true);
+
+    playSound("res/Randomize87.wav", 0.25);
+
+    ponderable.setVelocityY(JUMP_VELOCITY);
+    ponderable.setAccelY(JUMP_GRAVITY);
+
+    auto& animating = game_.getSystemManager().getSystem<AnimatingSystem>();
+    if (orientable.isFacingRight())
+    {
+      animating.startAnimation(entity, "stillRight");
+    } else {
+      animating.startAnimation(entity, "stillLeft");
+    }
+  }
+}
+
+void OrientingSystem::stopJumping(id_type entity)
+{
+  auto& orientable = game_.getEntityManager().
+    getComponent<OrientableComponent>(entity);
+
+  if (orientable.isJumping())
+  {
+    orientable.setJumping(false);
+
+    auto& ponderable = game_.getEntityManager().
+      getComponent<PonderableComponent>(entity);
+
+    ponderable.setAccelY(NORMAL_GRAVITY);
+  }
+}
+
+void OrientingSystem::land(id_type entity)
+{
+  auto& orientable = game_.getEntityManager().
+    getComponent<OrientableComponent>(entity);
+
+  auto& animating = game_.getSystemManager().getSystem<AnimatingSystem>();
+
+  switch (orientable.getWalkState())
+  {
+    case OrientableComponent::WalkState::still:
+    {
+      if (orientable.isFacingRight())
+      {
+        animating.startAnimation(entity, "stillRight");
+      } else {
+        animating.startAnimation(entity, "stillLeft");
+      }
+
+      break;
+    }
+
+    case OrientableComponent::WalkState::left:
+    {
+      animating.startAnimation(entity, "walkingLeft");
+
+      break;
+    }
+
+    case OrientableComponent::WalkState::right:
+    {
+      animating.startAnimation(entity, "walkingRight");
+
+      break;
+    }
+  }
+}
+
+void OrientingSystem::startFalling(id_type entity)
+{
+  auto& orientable = game_.getEntityManager().
+    getComponent<OrientableComponent>(entity);
+
+  auto& animating = game_.getSystemManager().getSystem<AnimatingSystem>();
+
+  if (orientable.isFacingRight())
+  {
+    animating.startAnimation(entity, "stillRight");
+  } else {
+    animating.startAnimation(entity, "stillLeft");
+  }
+}
+
+void OrientingSystem::drop(id_type entity)
+{
+  auto& orientable = game_.getEntityManager().
+    getComponent<OrientableComponent>(entity);
+
+  auto& ponderable = game_.getEntityManager().
+    getComponent<PonderableComponent>(entity);
+
+  if (ponderable.isGrounded()
+    && (orientable.getDropState() == OrientableComponent::DropState::none))
+  {
+    orientable.setDropState(OrientableComponent::DropState::ready);
+  }
+}
+
+void OrientingSystem::stopDropping(id_type entity)
+{
+  auto& orientable = game_.getEntityManager().
+    getComponent<OrientableComponent>(entity);
+
+  if (orientable.getDropState() == OrientableComponent::DropState::ready)
+  {
+    orientable.setDropState(OrientableComponent::DropState::none);
+  }
+}
@@ -0,0 +1,35 @@
+#ifndef ORIENTING_H_099F0C23
+#define ORIENTING_H_099F0C23
+
+#include "system.h"
+
+class OrientingSystem : public System {
+public:
+
+  OrientingSystem(Game& game) : System(game)
+  {
+  }
+
+  void tick(double dt);
+
+  void moveLeft(id_type entity);
+
+  void moveRight(id_type entity);
+
+  void stopWalking(id_type entity);
+
+  void jump(id_type entity);
+
+  void stopJumping(id_type entity);
+
+  void land(id_type entity);
+
+  void startFalling(id_type entity);
+
+  void drop(id_type entity);
+
+  void stopDropping(id_type entity);
+
+};
+
+#endif /* end of include guard: ORIENTING_H_099F0C23 */
@@ -0,0 +1,268 @@
+#include "pondering.h"
+#include "game.h"
+#include "components/ponderable.h"
+#include "components/transformable.h"
+#include "components/orientable.h"
+#include "components/mappable.h"
+#include "systems/orienting.h"
+#include "consts.h"
+
+void PonderingSystem::tick(double dt)
+{
+  auto entities = game_.getEntityManager().getEntitiesWithComponents<
+    PonderableComponent,
+    TransformableComponent>();
+
+  auto maps = game_.getEntityManager().getEntitiesWithComponents<
+    MappableComponent>();
+
+  for (id_type entity : entities)
+  {
+    auto& transformable = game_.getEntityManager().
+      getComponent<TransformableComponent>(entity);
+
+    auto& ponderable = game_.getEntityManager().
+      getComponent<PonderableComponent>(entity);
+
+    // Accelerate
+    ponderable.setVelocityX(
+      ponderable.getVelocityX() + ponderable.getAccelX() * dt);
+
+    ponderable.setVelocityY(
+      ponderable.getVelocityY() + ponderable.getAccelY() * dt);
+
+    const double oldX = transformable.getX();
+    const double oldY = transformable.getY();
+    const double oldRight = oldX + transformable.getW();
+    const double oldBottom = oldY + transformable.getH();
+
+    double newX = oldX + ponderable.getVelocityX() * dt;
+    double newY = oldY + ponderable.getVelocityY() * dt;
+
+    bool oldGrounded = ponderable.isGrounded();
+    ponderable.setGrounded(false);
+
+    for (id_type mapEntity : maps)
+    {
+      auto& mappable = game_.getEntityManager().
+        getComponent<MappableComponent>(mapEntity);
+
+      if (newX < oldX)
+      {
+        for (auto it = mappable.getLeftBoundaries().lower_bound(oldX);
+          (it != std::end(mappable.getLeftBoundaries())) && (it->first >= newX);
+          it++)
+        {
+          if ((oldBottom > it->second.getLower())
+            && (oldY < it->second.getUpper()))
+          {
+            // We have a collision!
+            processCollision(
+              entity,
+              Direction::left,
+              newX,
+              newY,
+              it->first,
+              it->second.getType());
+          }
+        }
+      } else if (newX > oldX)
+      {
+        for (auto it = mappable.getRightBoundaries().lower_bound(oldRight);
+          (it != std::end(mappable.getRightBoundaries()))
+            && (it->first <= (newX + transformable.getW()));
+          it++)
+        {
+          if ((oldBottom > it->second.getLower())
+            && (oldY < it->second.getUpper()))
+          {
+            // We have a collision!
+            processCollision(
+              entity,
+              Direction::right,
+              newX,
+              newY,
+              it->first,
+              it->second.getType());
+          }
+        }
+      }
+
+      if (newY < oldY)
+      {
+        for (auto it = mappable.getUpBoundaries().lower_bound(oldY);
+          (it != std::end(mappable.getUpBoundaries())) && (it->first >= newY);
+          it++)
+        {
+          if ((oldRight > it->second.getLower())
+            && (oldX < it->second.getUpper()))
+          {
+            // We have a collision!
+            processCollision(
+              entity,
+              Direction::up,
+              newX,
+              newY,
+              it->first,
+              it->second.getType());
+          }
+        }
+      } else if (newY > oldY)
+      {
+        for (auto it = mappable.getDownBoundaries().lower_bound(oldBottom);
+          (it != std::end(mappable.getDownBoundaries()))
+            && (it->first <= (newY + transformable.getH()));
+          it++)
+        {
+          if ((oldRight > it->second.getLower())
+            && (oldX < it->second.getUpper()))
+          {
+            // We have a collision!
+            processCollision(
+              entity,
+              Direction::down,
+              newX,
+              newY,
+              it->first,
+              it->second.getType());
+          }
+        }
+      }
+    }
+
+    // Move
+    transformable.setX(newX);
+    transformable.setY(newY);
+
+    // Perform cleanup for orientable entites
+    if (game_.getEntityManager().hasComponent<OrientableComponent>(entity))
+    {
+      auto& orientable = game_.getEntityManager().
+        getComponent<OrientableComponent>(entity);
+
+      // Handle changes in groundedness
+      if (ponderable.isGrounded() != oldGrounded)
+      {
+        if (ponderable.isGrounded())
+        {
+          game_.getSystemManager().getSystem<OrientingSystem>().land(entity);
+        } else {
+          game_.getSystemManager().
+            getSystem<OrientingSystem>().startFalling(entity);
+        }
+      }
+
+      // Complete dropping, if necessary
+      if (orientable.getDropState() == OrientableComponent::DropState::active)
+      {
+        orientable.setDropState(OrientableComponent::DropState::none);
+      }
+    }
+  }
+}
+
+void PonderingSystem::initializeBody(
+  id_type entity,
+  PonderableComponent::Type type)
+{
+  auto& ponderable = game_.getEntityManager().
+    emplaceComponent<PonderableComponent>(entity, type);
+
+  if (type == PonderableComponent::Type::freefalling)
+  {
+    ponderable.setAccelY(NORMAL_GRAVITY);
+  }
+}
+
+void PonderingSystem::processCollision(
+  id_type entity,
+  Direction dir,
+  double& newX,
+  double& newY,
+  int axis,
+  MappableComponent::Boundary::Type type)
+{
+  auto& ponderable = game_.getEntityManager().
+    getComponent<PonderableComponent>(entity);
+
+  auto& transformable = game_.getEntityManager().
+    getComponent<TransformableComponent>(entity);
+
+  bool touchedGround = false;
+
+  switch (type)
+  {
+    case MappableComponent::Boundary::Type::wall:
+    {
+      switch (dir)
+      {
+        case Direction::left:
+        {
+          newX = axis;
+          ponderable.setVelocityX(0.0);
+
+          break;
+        }
+
+        case Direction::right:
+        {
+          newX = axis - transformable.getW();
+          ponderable.setVelocityX(0.0);
+
+          break;
+        }
+
+        case Direction::up:
+        {
+          newY = axis;
+          ponderable.setVelocityY(0.0);
+
+          break;
+        }
+
+        case Direction::down:
+        {
+          touchedGround = true;
+
+          break;
+        }
+      }
+
+      break;
+    }
+
+    case MappableComponent::Boundary::Type::platform:
+    {
+      if (game_.getEntityManager().hasComponent<OrientableComponent>(entity))
+      {
+        auto& orientable = game_.getEntityManager().
+          getComponent<OrientableComponent>(entity);
+
+        if (orientable.getDropState() != OrientableComponent::DropState::none)
+        {
+          orientable.setDropState(OrientableComponent::DropState::active);
+        } else {
+          touchedGround = true;
+        }
+      } else {
+        touchedGround = true;
+      }
+
+      break;
+    }
+
+    default:
+    {
+      // Not yet implemented.
+
+      break;
+    }
+  }
+
+  if (touchedGround)
+  {
+    newY = axis - transformable.getH();
+    ponderable.setVelocityY(0.0);
+    ponderable.setGrounded(true);
+  }
+}
@@ -0,0 +1,32 @@
+#ifndef PONDERING_H_F2530E0E
+#define PONDERING_H_F2530E0E
+
+#include "system.h"
+#include "components/mappable.h"
+#include "components/ponderable.h"
+#include "direction.h"
+
+class PonderingSystem : public System {
+public:
+
+  PonderingSystem(Game& game) : System(game)
+  {
+  }
+
+  void tick(double dt);
+
+  void initializeBody(id_type entity, PonderableComponent::Type type);
+
+private:
+
+  void processCollision(
+    id_type entity,
+    Direction dir,
+    double& newX,
+    double& newY,
+    int axis,
+    MappableComponent::Boundary::Type type);
+
+};
+
+#endif /* end of include guard: PONDERING_H_F2530E0E */