ADD: Update Docs

src/scene/vk_scene.cpp

@@ -147,10 +147,13 @@ void SceneManager::update_scene()
     _camera_position_local = world_to_local(mainCamera.position_world, _origin_world);
 
     // Simple per-frame dt (seconds) for animations
-    static auto lastFrameTime = std::chrono::steady_clock::now();
     auto now = std::chrono::steady_clock::now();
-    float dt = std::chrono::duration<float>(now - lastFrameTime).count();
-    lastFrameTime = now;
+    if (_lastFrameTime.time_since_epoch().count() == 0)
+    {
+        _lastFrameTime = now;
+    }
+    float dt = std::chrono::duration<float>(now - _lastFrameTime).count();
+    _lastFrameTime = now;
     if (dt < 0.f)
     {
         dt = 0.f;
@@ -159,6 +162,7 @@ void SceneManager::update_scene()
     {
         dt = 0.1f;
     }
+    _deltaTime = dt;
 
     auto tagOwner = [&](RenderObject::OwnerType type, const std::string &name,
                         size_t opaqueBegin, size_t transpBegin)
@@ -888,3 +892,29 @@ bool SceneManager::setGLTFInstanceAnimationLoop(const std::string &instanceName,
     it->second.animation.animationLoop = loop;
     return true;
 }
+
+void SceneManager::setSunlightDirection(const glm::vec3& dir)
+{
+    glm::vec3 normalized = glm::normalize(dir);
+    sceneData.sunlightDirection = glm::vec4(normalized, sceneData.sunlightDirection.w);
+}
+
+glm::vec3 SceneManager::getSunlightDirection() const
+{
+    return glm::vec3(sceneData.sunlightDirection);
+}
+
+void SceneManager::setSunlightColor(const glm::vec3& color, float intensity)
+{
+    sceneData.sunlightColor = glm::vec4(color, intensity);
+}
+
+glm::vec3 SceneManager::getSunlightColor() const
+{
+    return glm::vec3(sceneData.sunlightColor);
+}
+
+float SceneManager::getSunlightIntensity() const
+{
+    return sceneData.sunlightColor.w;
+}

src/scene/vk_scene.h

@@ -5,6 +5,7 @@
 #include <unordered_map>
 #include <memory>
 #include <optional>
+#include <chrono>
 #include <glm/vec2.hpp>
 #include <string>
 
@@ -85,6 +86,16 @@ public:
     void selectRect(const glm::vec2 &p0, const glm::vec2 &p1, std::vector<RenderObject> &outObjects) const;
 
     const GPUSceneData &getSceneData() const { return sceneData; }
+
+    // Sunlight (directional light) access
+    void setSunlightDirection(const glm::vec3& dir);
+    glm::vec3 getSunlightDirection() const;
+    void setSunlightColor(const glm::vec3& color, float intensity);
+    glm::vec3 getSunlightColor() const;
+    float getSunlightIntensity() const;
+
+    // Delta time (seconds) for the current frame
+    float getDeltaTime() const { return _deltaTime; }
     DrawContext &getMainDrawContext() { return mainDrawContext; }
 
     void loadScene(const std::string &name, std::shared_ptr<LoadedGLTF> scene);
@@ -203,6 +214,8 @@ private:
     glm::vec3 _camera_position_local{0.0f, 0.0f, 0.0f};
     double _floating_origin_recenter_threshold = 1000.0;
     double _floating_origin_snap_size = 100.0;
+    float _deltaTime = 0.0f;
+    std::chrono::steady_clock::time_point _lastFrameTime{};
 
     std::unordered_map<std::string, std::shared_ptr<LoadedGLTF> > loadedScenes;
     // Per-named static glTF scene animation state (independent of instances).