From b2e3c5f6cc915bd96336583c8f79f3067ac74bbe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Matt=C3=A9o=20Delabre?= <contact@matteodelabre.me>
Date: Tue, 15 Mar 2016 22:09:40 +0100
Subject: [PATCH] Mise en cache de l'inverse des masses

---
 include/object.hpp |  6 ++++++
 src/object.cpp     | 17 ++++++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/include/object.hpp b/include/object.hpp
index c037648..2434c08 100644
--- a/include/object.hpp
+++ b/include/object.hpp
@@ -18,6 +18,7 @@ private:
     sf::VertexArray velocityLine;
 
     float mass;
+    float inv_mass;
     float charge;
     float restitution;
     int layer;
@@ -80,6 +81,11 @@ public:
      */
     float getMass();
 
+    /**
+     * Récupère l'inverse de la masse de l'objet (en cache)
+     */
+    float getMassInvert();
+
     /**
      * Modifie la masse de l'objet
      */
diff --git a/src/object.cpp b/src/object.cpp
index efbff84..3e41c3f 100644
--- a/src/object.cpp
+++ b/src/object.cpp
@@ -5,7 +5,7 @@ Object::Object(float x, float y) :
     acceleration(0, 0), velocity(0, 0), position(x, y),
     accelerationLine(sf::Lines, 2),
     velocityLine(sf::Lines, 2),
-    mass(1.f), charge(0.f), restitution(0.f), layer(10) {}
+    mass(1.f), inv_mass(1.f), charge(0.f), restitution(0.f), layer(10) {}
 
 sf::Vector2f Object::getForces(EngineState& state) {
     sf::Vector2f forces(0, 0);
@@ -72,8 +72,23 @@ float Object::getMass() {
     return mass;
 }
 
+float Object::getMassInvert() {
+    if (inv_mass >= 0) {
+        return inv_mass;
+    }
+
+    if (mass == 0) {
+        inv_mass = 0;
+        return inv_mass;
+    }
+
+    inv_mass = 1 / mass;
+    return inv_mass;
+}
+
 void Object::setMass(float set_mass) {
     mass = set_mass;
+    inv_mass = -1.f;
 }
 
 float Object::getCharge() {