From f1c91f539cd1ba1b4deeeb7258c9bd44c87b7e03 Mon Sep 17 00:00:00 2001
From: Vectozavr <60608292+vectozavr@users.noreply.github.com>
Date: Wed, 3 Nov 2021 20:21:39 +0700
Subject: [PATCH] accelerate collision detection in x3 times (feat. Neirokan)

---
 ShooterConsts.h              |  2 +-
 engine/Object.h              |  2 ++
 engine/Vec2D.cpp             |  2 +-
 engine/Vec4D.cpp             |  2 +-
 engine/physics/RigidBody.cpp | 10 ++++++----
 5 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/ShooterConsts.h b/ShooterConsts.h
index c8ad50e..bd35522 100644
--- a/ShooterConsts.h
+++ b/ShooterConsts.h
@@ -21,7 +21,7 @@ namespace ShooterConsts {
 
     const std::string ABILITY_OBJ = "obj/ability.obj";
     const std::string HILL_OBJ = "obj/hill.obj";
-    const std::string GUN_OBJ = "obj/gun.obj";
+    const std::string GUN_OBJ = "obj/weapon.obj";
     const std::string GUN_FIRE_SOUND = "sound/weapons/gun.ogg";
     const std::string GUN_RELOAD_SOUND = "sound/weapons/reload_gun.ogg";
     const std::string AK47_OBJ = "obj/ak47.obj";
diff --git a/engine/Object.h b/engine/Object.h
index d33ca85..ea2f9ac 100644
--- a/engine/Object.h
+++ b/engine/Object.h
@@ -105,6 +105,8 @@ public:
 
     [[nodiscard]] Matrix4x4 model() const { return Matrix4x4::Translation(_position) * _transformMatrix; }
 
+    [[nodiscard]] Matrix4x4 view() const { return Matrix4x4::View(left(), up(), lookAt(), position()); }
+
     // OpenGL function
     [[nodiscard]] GLfloat *glModel() const;
 
diff --git a/engine/Vec2D.cpp b/engine/Vec2D.cpp
index 5db1e25..ef0fd37 100644
--- a/engine/Vec2D.cpp
+++ b/engine/Vec2D.cpp
@@ -66,7 +66,7 @@ double Vec2D::abs() const {
 Vec2D Vec2D::normalized() const {
     double vecAbs = abs();
     if (vecAbs > Consts::EPS) {
-        return Vec2D(*this) / abs();
+        return Vec2D(*this) / vecAbs;
     } else {
         return Vec2D(0);
     }
diff --git a/engine/Vec4D.cpp b/engine/Vec4D.cpp
index 6aa8423..f9a92a6 100644
--- a/engine/Vec4D.cpp
+++ b/engine/Vec4D.cpp
@@ -67,7 +67,7 @@ double Vec4D::abs() const {
 Vec4D Vec4D::normalized() const {
     double vecAbs = abs();
     if (vecAbs > Consts::EPS) {
-        return Vec4D(*this) / abs();
+        return Vec4D(*this) / vecAbs;
     } else {
         return Vec4D(1);
     }
diff --git a/engine/physics/RigidBody.cpp b/engine/physics/RigidBody.cpp
index ac008bc..0428e1f 100644
--- a/engine/physics/RigidBody.cpp
+++ b/engine/physics/RigidBody.cpp
@@ -16,14 +16,16 @@ RigidBody::RigidBody(ObjectNameTag nameTag, const std::string &filename, const V
 
 Vec3D RigidBody::_findFurthestPoint(const Vec3D &direction) {
     Vec3D maxPoint{0, 0, 0};
+
     double maxDistance = -std::numeric_limits<double>::max();
 
+    Vec3D transformedDirection = (view() * direction).normalized();
+
     for (auto &tri : triangles()) {
         for (int i = 0; i < 3; i++) {
-            // TODO: multiplying model() * tri[i] costs too much time to compute
-            Vec3D point(model() * tri[i]);
+            Vec3D point = Vec3D(tri[i]);
+            double distance = point.dot(transformedDirection);
 
-            double distance = point.dot(direction.normalized());
             if (distance > maxDistance) {
                 maxDistance = distance;
                 maxPoint = point;
@@ -31,7 +33,7 @@ Vec3D RigidBody::_findFurthestPoint(const Vec3D &direction) {
         }
     }
 
-    return maxPoint;
+    return model()*maxPoint + position();
 }
 
 Vec3D RigidBody::_support(std::shared_ptr<RigidBody> obj, const Vec3D &direction) {