ADD: BVH Selection ongoing

src/core/vk_engine.cpp

@@ -466,6 +466,7 @@ void VulkanEngine::draw()
                 _lastPick.mesh = picked.sourceMesh;
                 _lastPick.scene = picked.sourceScene;
                 _lastPick.worldPos = fallbackPos;
+                _lastPick.worldTransform = picked.transform;
                 _lastPick.firstIndex = picked.firstIndex;
                 _lastPick.indexCount = picked.indexCount;
                 _lastPick.surfaceIndex = picked.surfaceIndex;
@@ -496,6 +497,7 @@ void VulkanEngine::draw()
             _hoverPick.mesh = hoverObj.sourceMesh;
             _hoverPick.scene = hoverObj.sourceScene;
             _hoverPick.worldPos = hoverPos;
+            _hoverPick.worldTransform = hoverObj.transform;
             _hoverPick.firstIndex = hoverObj.firstIndex;
             _hoverPick.indexCount = hoverObj.indexCount;
             _hoverPick.surfaceIndex = hoverObj.surfaceIndex;
@@ -816,6 +818,7 @@ void VulkanEngine::run()
                             _lastPick.mesh = hitObject.sourceMesh;
                             _lastPick.scene = hitObject.sourceScene;
                             _lastPick.worldPos = hitPos;
+                            _lastPick.worldTransform = hitObject.transform;
                             _lastPick.firstIndex = hitObject.firstIndex;
                             _lastPick.indexCount = hitObject.indexCount;
                             _lastPick.surfaceIndex = hitObject.surfaceIndex;
@@ -851,6 +854,7 @@ void VulkanEngine::run()
                             // Use bounds origin transformed to world as a representative point.
                             glm::vec3 centerWorld = glm::vec3(obj.transform * glm::vec4(obj.bounds.origin, 1.0f));
                             info.worldPos = centerWorld;
+                             info.worldTransform = obj.transform;
                             info.firstIndex = obj.firstIndex;
                             info.indexCount = obj.indexCount;
                             info.surfaceIndex = obj.surfaceIndex;

src/core/vk_engine.h

@@ -121,6 +121,7 @@ public:
         MeshAsset *mesh = nullptr;
         LoadedGLTF *scene = nullptr;
         glm::vec3 worldPos{0.0f};
+        glm::mat4 worldTransform{1.0f};
         uint32_t indexCount = 0;
         uint32_t firstIndex = 0;
         uint32_t surfaceIndex = 0;
@@ -151,6 +152,8 @@ public:
 
     // Toggle to enable/disable ID-buffer picking in addition to raycast
     bool _useIdBufferPicking = false;
+    // Debug: draw mesh BVH boxes for last pick
+    bool _debugDrawBVH = false;
 
     // Debug: persistent pass enable overrides (by pass name)
     std::unordered_map<std::string, bool> _rgPassToggles;

src/core/vk_engine_ui.cpp

@@ -19,6 +19,8 @@
 #include "engine_context.h"
 #include <vk_types.h>
 
+#include "mesh_bvh.h"
+
 namespace {
 
 // Background / compute playground
@@ -538,7 +540,9 @@ static void ui_scene(VulkanEngine *eng)
     ImGui::Text("Opaque draws: %zu", dc.OpaqueSurfaces.size());
     ImGui::Text("Transp draws: %zu", dc.TransparentSurfaces.size());
     ImGui::Checkbox("Use ID-buffer picking", &eng->_useIdBufferPicking);
+    ImGui::Checkbox("Debug draw mesh BVH (last pick)", &eng->_debugDrawBVH);
     ImGui::Separator();
+
     if (eng->_lastPick.valid)
     {
         const char *meshName = eng->_lastPick.mesh ? eng->_lastPick.mesh->name.c_str() : "<unknown>";
@@ -556,6 +560,21 @@ static void ui_scene(VulkanEngine *eng)
         ImGui::Text("Indices: first=%u count=%u",
                     eng->_lastPick.firstIndex,
                     eng->_lastPick.indexCount);
+
+        if (eng->_sceneManager)
+        {
+            const SceneManager::PickingDebug &dbg = eng->_sceneManager->getPickingDebug();
+            ImGui::Text("Mesh BVH used: %s, hit: %s, fallback box: %s",
+                        dbg.usedMeshBVH ? "yes" : "no",
+                        dbg.meshBVHHit ? "yes" : "no",
+                        dbg.meshBVHFallbackBox ? "yes" : "no");
+            if (dbg.meshBVHPrimCount > 0)
+            {
+                ImGui::Text("Mesh BVH stats: prims=%u, nodes=%u",
+                            dbg.meshBVHPrimCount,
+                            dbg.meshBVHNodeCount);
+            }
+        }
     }
     else
     {