feat: add basic forward lighting coverage

engine/src/Rendering/RenderSceneExtractor.cpp

@@ -2,6 +2,7 @@
 
 #include "Components/CameraComponent.h"
 #include "Components/GameObject.h"
+#include "Components/LightComponent.h"
 #include "Components/MeshFilterComponent.h"
 #include "Components/MeshRendererComponent.h"
 #include "Components/TransformComponent.h"
@@ -22,6 +23,13 @@ bool IsUsableCamera(const Components::CameraComponent* camera) {
            camera->GetGameObject()->IsActiveInHierarchy();
 }
 
+bool IsUsableLight(const Components::LightComponent* light) {
+    return light != nullptr &&
+           light->IsEnabled() &&
+           light->GetGameObject() != nullptr &&
+           light->GetGameObject()->IsActiveInHierarchy();
+}
+
 bool CompareVisibleItems(const VisibleRenderItem& lhs, const VisibleRenderItem& rhs) {
     if (lhs.renderQueue != rhs.renderQueue) {
         return lhs.renderQueue < rhs.renderQueue;
@@ -66,6 +74,7 @@ RenderSceneData RenderSceneExtractor::Extract(
         sceneData.visibleItems.begin(),
         sceneData.visibleItems.end(),
         CompareVisibleItems);
+    ExtractLighting(scene, sceneData.lighting);
 
     return sceneData;
 }
@@ -93,6 +102,7 @@ RenderSceneData RenderSceneExtractor::ExtractForCamera(
         sceneData.visibleItems.begin(),
         sceneData.visibleItems.end(),
         CompareVisibleItems);
+    ExtractLighting(scene, sceneData.lighting);
 
     return sceneData;
 }
@@ -171,6 +181,46 @@ RenderCameraData RenderSceneExtractor::BuildCameraData(
     return cameraData;
 }
 
+void RenderSceneExtractor::ExtractLighting(
+    const Components::Scene& scene,
+    RenderLightingData& lightingData) const {
+    const std::vector<Components::LightComponent*> lights =
+        scene.FindObjectsOfType<Components::LightComponent>();
+
+    Components::LightComponent* mainDirectionalLight = nullptr;
+    for (Components::LightComponent* light : lights) {
+        if (!IsUsableLight(light) ||
+            light->GetLightType() != Components::LightType::Directional) {
+            continue;
+        }
+
+        if (mainDirectionalLight == nullptr ||
+            light->GetIntensity() > mainDirectionalLight->GetIntensity()) {
+            mainDirectionalLight = light;
+        }
+    }
+
+    if (mainDirectionalLight == nullptr) {
+        lightingData = {};
+        return;
+    }
+
+    RenderDirectionalLightData lightData;
+    lightData.enabled = true;
+    lightData.intensity = mainDirectionalLight->GetIntensity();
+    lightData.color = mainDirectionalLight->GetColor();
+
+    Math::Vector3 direction = mainDirectionalLight->transform().GetForward() * -1.0f;
+    if (direction.SqrMagnitude() <= Math::EPSILON) {
+        direction = Math::Vector3::Back();
+    } else {
+        direction = direction.Normalized();
+    }
+    lightData.direction = direction;
+
+    lightingData.mainDirectionalLight = lightData;
+}
+
 void RenderSceneExtractor::ExtractVisibleItems(
     Components::GameObject* gameObject,
     const Math::Vector3& cameraPosition,