1 files changed, 97 insertions, 0 deletions

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+#include "collision.h"
+
+bool Collision::operator<(const Collision& other) const
+{
+  // Most important is the type of collision
+  if (type_ != other.type_)
+  {
+    return (static_cast<int>(type_) > static_cast<int>(other.type_));
+  }
+
+  // Next, categorize the collisions arbitrarily based on direction
+  if (dir_ != other.dir_)
+  {
+    return (static_cast<int>(dir_) < static_cast<int>(other.dir_));
+  }
+
+  // We want to process closer collisions first
+  if (axis_ != other.axis_)
+  {
+    switch (dir_)
+    {
+      case Direction::left:
+      case Direction::up:
+      {
+        return (axis_ < other.axis_);
+      }
+
+      case Direction::right:
+      case Direction::down:
+      {
+        return (axis_ > other.axis_);
+      }
+    }
+  }
+
+  // Order the remaining attributes arbitrarily
+  return std::tie(collider_, lower_, upper_) <
+    std::tie(other.collider_, other.lower_, other.upper_);
+}
+
+bool Collision::isColliding(
+  double x,
+  double y,
+  int w,
+  int h) const
+{
+  int right = x + w;
+  int bottom = y + h;
+
+  switch (dir_)
+  {
+    case Direction::left:
+    case Direction::right:
+    {
+      if (!((bottom > lower_) && (y < upper_)))
+      {
+        return false;
+      }
+
+      break;
+    }
+
+    case Direction::up:
+    case Direction::down:
+    {
+      if (!((right > lower_) && (x < upper_)))
+      {
+        return false;
+      }
+
+      break;
+    }
+  }
+
+  switch (dir_)
+  {
+    case Direction::left:
+    {
+      return (axis_ >= x);
+    }
+
+    case Direction::right:
+    {
+      return (axis_ <= right);
+    }
+
+    case Direction::up:
+    {
+      return (axis_ >= y);
+    }
+
+    case Direction::down:
+    {
+      return (axis_ <= bottom);
+    }
+  }
+}