From f3a76eb13e2e70d9774a77f95119c0d32df0b4fc Mon Sep 17 00:00:00 2001
From: William Moberg <william.moberg@live.se>
Date: Wed, 10 Feb 2016 15:00:13 +0100
Subject: [PATCH] Explosion effects should get a proper sized AABB.

---
 include/Engine/Collision/Collision.h          |  1 +
 src/Engine/Collision/Collision.cpp            | 26 +++++++++++++++++++
 .../Collision/FillFrustumOctreeSystem.cpp     | 16 +++++-------
 3 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/include/Engine/Collision/Collision.h b/include/Engine/Collision/Collision.h
index 6e4858b2..8137ceef 100644
--- a/include/Engine/Collision/Collision.h
+++ b/include/Engine/Collision/Collision.h
@@ -80,6 +80,7 @@ bool AABBVsAABB(const AABB& a, const AABB& b, glm::vec3& minimumTranslation);
 
 // Calculates an absolute AABB from an entity AABB component
 boost::optional<EntityAABB> EntityAbsoluteAABB(EntityWrapper& entity);
+boost::optional<EntityAABB> AbsoluteAABBExplosionEffect(EntityWrapper& entity);
 
 }
 
diff --git a/src/Engine/Collision/Collision.cpp b/src/Engine/Collision/Collision.cpp
index c0c27190..d82ec3fb 100644
--- a/src/Engine/Collision/Collision.cpp
+++ b/src/Engine/Collision/Collision.cpp
@@ -612,4 +612,30 @@ boost::optional<EntityAABB> EntityAbsoluteAABB(EntityWrapper& entity)
     return aabb;
 }
 
+boost::optional<EntityAABB> AbsoluteAABBExplosionEffect(EntityWrapper& entity)
+{
+    boost::optional<EntityAABB> modelBox = EntityAbsoluteAABB(entity);
+    if (!modelBox) {
+        return boost::none;
+    }
+    bool isRandom = (bool)entity["ExplosionEffect"]["Randomness"];
+    float random = isRandom ? (float)(double)entity["ExplosionEffect"]["RandomnessScalar"] : 0;
+    glm::vec3 origin = (glm::vec3)entity["ExplosionEffect"]["ExplosionOrigin"];
+    glm::vec3 randomVel = (glm::vec3)entity["ExplosionEffect"]["Velocity"];
+    randomVel *= (random + 1);
+    float endVelocity = randomVel.y;
+    if ((bool)entity["ExplosionEffect"]["ExponentialAccelaration"]) {
+        endVelocity *= endVelocity / 2.f;
+    }
+    float maxRadius = (float)(double)entity["ExplosionEffect"]["ExplosionDuration"] * endVelocity;
+    glm::vec3 size;
+    AABB explosionBox(origin - (size / 2.f), origin + (size / 2.f));
+
+    glm::vec3 mini = glm::min(explosionBox.MinCorner(), (*modelBox).MinCorner());
+    glm::vec3 maxi = glm::max(explosionBox.MaxCorner(), (*modelBox).MaxCorner());
+    EntityAABB aabb = AABB(mini, maxi);
+    aabb.Entity = entity;
+    return aabb;
+}
+
 }
diff --git a/src/Engine/Collision/FillFrustumOctreeSystem.cpp b/src/Engine/Collision/FillFrustumOctreeSystem.cpp
index f02a30f1..a8835266 100644
--- a/src/Engine/Collision/FillFrustumOctreeSystem.cpp
+++ b/src/Engine/Collision/FillFrustumOctreeSystem.cpp
@@ -7,15 +7,13 @@ void FillFrustumOctreeSystem::Update(double dt)
 
 void FillFrustumOctreeSystem::UpdateComponent(EntityWrapper& entity, ComponentWrapper& component, double dt)
 {
+    boost::optional<EntityAABB> absoluteAABB;
     if (entity.HasComponent("ExplosionEffect")) {
-        //TODO: Fix hack, get real box by using shader equation.
-        EntityAABB aabb = AABB(glm::vec3(-300), glm::vec3(300));
-        aabb.Entity = entity;
-        m_Octree->AddDynamicObject(aabb);
+        absoluteAABB = Collision::AbsoluteAABBExplosionEffect(entity);
     } else {
-        boost::optional<EntityAABB> absoluteAABB = Collision::EntityAbsoluteAABB(entity);
-        if (absoluteAABB) {
-            m_Octree->AddDynamicObject(*absoluteAABB);
-        }
+        absoluteAABB = Collision::EntityAbsoluteAABB(entity);
     }
-}
\ No newline at end of file
+    if (absoluteAABB) {
+        m_Octree->AddDynamicObject(*absoluteAABB);
+    }
+}