From 1e94a118eb0f996a00ba6e5bfe02acfba9905f94 Mon Sep 17 00:00:00 2001
From: tovjemam <zbyvaj@seznam.cz>
Date: Wed, 14 Jan 2026 18:04:24 +0100
Subject: [PATCH] Add convex hull option for meshes

---
 src/assets/model.cpp            | 23 ++++++++++++++++++++
 src/assets/model.hpp            | 38 +++++++++++++++++----------------
 src/collision/dynamicsworld.cpp |  5 +----
 3 files changed, 44 insertions(+), 22 deletions(-)

diff --git a/src/assets/model.cpp b/src/assets/model.cpp
index 452ecd8..dcebb39 100644
--- a/src/assets/model.cpp
+++ b/src/assets/model.cpp
@@ -3,12 +3,15 @@
 #include "cmdfile.hpp"
 #include "cache.hpp"
 
+#include <BulletCollision/CollisionShapes/btShapeHull.h>
+
 std::shared_ptr<const assets::Model> assets::Model::LoadFromFile(const std::string& filename)
 {
     auto model = std::make_shared<Model>();
     std::vector<glm::vec3> vert_pos; // rember for collision trimesh
     
     CLIENT_ONLY(MeshBuilder mb(gfx::MF_NONE);)
+    std::unique_ptr<btConvexHullShape> temp_hull;
 
     LoadCMDFile(filename, [&](const std::string& command, std::istringstream& iss) {
         if (command == "v")
@@ -29,6 +32,9 @@ std::shared_ptr<const assets::Model> assets::Model::LoadFromFile(const std::stri
 
             if (model->cmesh_)
                 vert_pos.emplace_back(pos);
+
+            if (temp_hull)
+                temp_hull->addPoint(btVector3(pos.x, pos.y, pos.z), false);
         }
         else if (command == "f")
         {
@@ -92,6 +98,10 @@ std::shared_ptr<const assets::Model> assets::Model::LoadFromFile(const std::stri
         {
             model->cmesh_ = std::make_unique<collision::TriangleMesh>();
         }
+        else if (command == "makeconvexhull")
+        {
+            temp_hull = std::make_unique<btConvexHullShape>();
+        }
         else
         {
             throw std::runtime_error("Unknown command in model file: " + command);
@@ -105,8 +115,21 @@ std::shared_ptr<const assets::Model> assets::Model::LoadFromFile(const std::stri
         model->mesh_ = mb.GetMesh();
     )
 
+    // tri mesh
     if (model->cmesh_)
         model->cmesh_->Build();
 
+    // convex hull
+    if (temp_hull)
+    {
+        temp_hull->recalcLocalAabb();
+
+        // Optional but recommended
+        auto shape_hull = std::make_unique<btShapeHull>(temp_hull.get());
+        shape_hull->buildHull(temp_hull->getMargin());
+
+        model->cshape_ = std::make_unique<btConvexHullShape>((btScalar*)shape_hull->getVertexPointer(), shape_hull->numVertices(), sizeof(btVector3));
+    }
+
     return model;
 }
diff --git a/src/assets/model.hpp b/src/assets/model.hpp
index d31b0ff..5d57c50 100644
--- a/src/assets/model.hpp
+++ b/src/assets/model.hpp
@@ -14,24 +14,25 @@
 namespace assets
 {
 
-enum ModelCollisionShapeType
-{
-    MCS_NONE,
+// enum ModelCollisionShapeType
+// {
+//     MCS_NONE,
     
-    MCS_BOX,
-    MCS_SPHERE,
-};
+//     MCS_BOX,
+//     MCS_SPHERE,
+// };
+
+// struct ModelCollisionShape
+// {
+//     ModelCollisionShapeType type = MCS_NONE;
+//     glm::vec3 origin = glm::vec3(0.0f);
+//     union
+//     {
+//         float radius;
+//         glm::vec3 half_extents;
+//     };
+// };
 
-struct ModelCollisionShape
-{
-    ModelCollisionShapeType type = MCS_NONE;
-    glm::vec3 origin = glm::vec3(0.0f);
-    union
-    {
-        float radius;
-        glm::vec3 half_extents;
-    };
-};
 
 class Model
 {
@@ -40,13 +41,14 @@ public:
     static std::shared_ptr<const Model> LoadFromFile(const std::string& filename);
 
     const collision::TriangleMesh* GetColMesh() const { return cmesh_.get(); }
-    const std::vector<ModelCollisionShape>& GetColShapes() const { return cshapes_; }
+    btCollisionShape* GetColShape() const { return cshape_.get(); }
 
     CLIENT_ONLY(const std::shared_ptr<const Mesh>& GetMesh() const { return mesh_; })
 
 private:
     std::unique_ptr<collision::TriangleMesh> cmesh_;
-    std::vector<ModelCollisionShape> cshapes_;
+    // std::vector<ModelCollisionShape> cshapes_;
+    std::unique_ptr<btCollisionShape> cshape_;
 
     CLIENT_ONLY(std::shared_ptr<const Mesh> mesh_;)
 
diff --git a/src/collision/dynamicsworld.cpp b/src/collision/dynamicsworld.cpp
index 2bbe546..b7112ac 100644
--- a/src/collision/dynamicsworld.cpp
+++ b/src/collision/dynamicsworld.cpp
@@ -58,8 +58,5 @@ void collision::DynamicsWorld::AddModelInstance(const assets::Model& model, cons
         static_objs_.emplace_back(std::move(obj));
     }
 
-    for (const auto& shapes = model.GetColShapes(); const auto& shape : shapes)
-    {
-        // TODO: add basic shapes
-    }
+    // TODO: add shape
 }