src/geometry/Circle.cpp

   1 /*
   2  * Circle.cpp
   3  *
   4  *  Created on: Apr 20, 2012
   5  *      Author: holy
   6  */
   7
   8 #include "Circle.h"
   9
  10 #include "AABB.h"
  11 #include "FakeLens.h"
  12 #include "../game/Entity.h"
  13
  14
  15 namespace geometry {
  16
  17 bool Circle::Overlaps(const Shape &other, Vector &normal) const {
  18         if (other.Overlaps(*this, normal)) {
  19                 normal *= -1;
  20                 return true;
  21         } else {
  22                 return false;
  23         }
  24 }
  25
  26 bool Circle::Overlaps(const AABB &other, Vector &normal) const {
  27         // fast checks for far away shapes
  28         if (Bottom() <= other.Top()) return false;
  29         if (other.Bottom() <= Top()) return false;
  30         if (Right() <= other.Left()) return false;
  31         if (other.Right() <= Left()) return false;
  32
  33         int xZone(
  34                         X() < other.Left() ? 0 : (
  35                         other.Right() < X() ? 2 : 1));
  36         int yZone(
  37                                 Y() < other.Top() ? 0 : (
  38                                 other.Bottom() < Y() ? 2 : 1));
  39         int zone(xZone + 3*yZone);
  40
  41         if (zone == 4) {
  42                 normal = (Center() - other.Center()).Unit();
  43                 return true;
  44         }
  45
  46         if (zone % 2) {
  47                 if (xZone == 1) { // vertical
  48                         if (Bottom() < other.Top()) return false;
  49                         if (other.Bottom() < Top()) return false;
  50
  51                         if (Bottom() < other.Bottom()) {
  52                                 normal = Vector(0, -1);
  53                         } else {
  54                                 normal = Vector(0, 1);
  55                         }
  56
  57                         return true;
  58                 } else {
  59                         if (Right() < other.Left()) return false;
  60                         if (other.Right() < Left()) return false;
  61
  62                         if (Left() < other.Left()) {
  63                                 normal = Vector(-1, 0);
  64                         } else {
  65                                 normal = Vector(1, 0);
  66                         }
  67
  68                         return true;
  69                 }
  70         } else {
  71                 Vector near(
  72                                 yZone ? other.Right() : other.Left(),
  73                                 xZone ? other.Bottom() : other.Top());
  74                 Vector distance(position - near);
  75                 Sint32 distanceSquared(distance.LengthSquared());
  76                 if (distanceSquared < (Radius() * Radius())) {
  77                         normal = distance.Unit();
  78                         return true;
  79                 } else {
  80                         return false;
  81                 }
  82         }
  83 }
  84
  85 bool Circle::Overlaps(const Circle &other, Vector &normal) const {
  86         Vector delta(position - other.position);
  87         Sint32 distanceSquared(delta.LengthSquared()), minDistance(Radius() + other.Radius());
  88         if (distanceSquared < (minDistance * minDistance)) {
  89                 normal = delta.Unify();
  90                 return true;
  91         } else {
  92                 return false;
  93         }
  94 }
  95
  96 bool Circle::Overlaps(const FakeLens &other, Vector &normal) const {
  97         if (other.Overlaps(*this, normal)) {
  98                 normal *= -1;
  99                 return true;
 100         } else {
 101                 return false;
 102         }
 103 }
 104
 105 std::ostream &Circle::Write(std::ostream &out) const {
 106         return out << "Circle(" << Radius() << '+' << Top() << '+' << Left() << ')';
 107 }
 108
 109 }