diff --git a/include/util/gen_tangents.h b/include/util/gen_tangents.h
index 7b9637e..529fc23 100644
--- a/include/util/gen_tangents.h
+++ b/include/util/gen_tangents.h
@@ -1 +1,23 @@
-#pragma once
\ No newline at end of file
+#pragma once
+
+#include <cstdint> // uint32_t
+
+#include <vector>
+
+namespace engine {
+struct Vertex; // resources/mesh.h
+}
+
+namespace engine::util {
+
+/*
+ * Generate tangents for a given list of vertices.
+ * The provided vertices must be in proper order.
+ * Parameters:
+ *     vertices (in/out) - vertices to modify with generated tangents (size can change)
+ * Returns:
+ *     index list for the provided vertices
+ */
+std::vector<uint32_t> GenTangents(std::vector<engine::Vertex>& vertices);
+
+} // namespace engine::util
\ No newline at end of file
diff --git a/res/engine/shaders/fancy.frag b/res/engine/shaders/fancy.frag
index 74f9785..2f1adef 100644
--- a/res/engine/shaders/fancy.frag
+++ b/res/engine/shaders/fancy.frag
@@ -119,7 +119,7 @@ void main() {
 	lighting *= (1.0 - shadow);
 
 	const vec3 ambient_light = vec3(0.09082, 0.13281, 0.18164) * 2.4 * 0.1;
-	//lighting += mix(ambient_light, texture(globalSetSkybox, R).rgb, metallic) * ao * diffuse_brdf; // this is NOT physically-based, it just looks cool
+	lighting += mix(ambient_light, texture(globalSetSkybox, R).rgb, metallic) * ao * diffuse_brdf; // this is NOT physically-based, it just looks cool
 	lighting += (ambient_light * ao * diffuse_brdf);
 
 	// tone mapping
diff --git a/src/application.cpp b/src/application.cpp
index f1b4b30..f0ea6af 100644
--- a/src/application.cpp
+++ b/src/application.cpp
@@ -333,7 +333,7 @@ void Application::GameLoop()
                 if (ImGui::Button("Load glTF")) {
 #ifdef _WIN32
                     std::string path = std::filesystem::path(openGLTFDialog()).string();
-
+					LOG_ERROR("Not yet implemented!");
 #endif
                 }
 #ifndef _WIN32
diff --git a/src/util/gen_tangents.cpp b/src/util/gen_tangents.cpp
index 0d00346..278a208 100644
--- a/src/util/gen_tangents.cpp
+++ b/src/util/gen_tangents.cpp
@@ -1 +1,81 @@
-#include "util/gen_tangents.h"
\ No newline at end of file
+#include "util/gen_tangents.h"
+
+#include <stdexcept>
+
+#include "libs/mikktspace.h"
+#include "libs/weldmesh.h"
+
+#include "resources/mesh.h"
+
+namespace engine::util {
+
+std::vector<uint32_t> engine::util::GenTangents(std::vector<engine::Vertex>& vertices)
+{
+
+    using VertList = std::vector<Vertex>;
+
+    SMikkTSpaceInterface mts_interface{};
+    mts_interface.m_getNumFaces = [](const SMikkTSpaceContext* pContext) -> int {
+        auto vertices = static_cast<const VertList*>(pContext->m_pUserData);
+        return static_cast<int>(vertices->size() / 3);
+    };
+    mts_interface.m_getNumVerticesOfFace = [](const SMikkTSpaceContext*, const int) -> int { return 3; };
+    mts_interface.m_getPosition = [](const SMikkTSpaceContext* pContext, float fvPosOut[], const int iFace, const int iVert) -> void {
+        auto vertices = static_cast<const VertList*>(pContext->m_pUserData);
+        const size_t i = static_cast<size_t>(iFace) * 3 + static_cast<size_t>(iVert);
+        const glm::vec3 pos = vertices->operator[](i).pos;
+        fvPosOut[0] = pos.x;
+        fvPosOut[1] = pos.y;
+        fvPosOut[2] = pos.z;
+    };
+    mts_interface.m_getNormal = [](const SMikkTSpaceContext* pContext, float fvNormOut[], const int iFace, const int iVert) -> void {
+        auto vertices = static_cast<const VertList*>(pContext->m_pUserData);
+        const size_t i = static_cast<size_t>(iFace) * 3 + static_cast<size_t>(iVert);
+        const glm::vec3 norm = vertices->operator[](i).norm;
+        fvNormOut[0] = norm.x;
+        fvNormOut[1] = norm.y;
+        fvNormOut[2] = norm.z;
+    };
+    mts_interface.m_getTexCoord = [](const SMikkTSpaceContext* pContext, float fvTexcOut[], const int iFace, const int iVert) -> void {
+        auto vertices = static_cast<const VertList*>(pContext->m_pUserData);
+        const size_t i = static_cast<size_t>(iFace) * 3 + static_cast<size_t>(iVert);
+        const glm::vec2 uv = vertices->operator[](i).uv;
+        fvTexcOut[0] = uv.x;
+        fvTexcOut[1] = uv.y;
+    };
+    mts_interface.m_setTSpaceBasic = [](const SMikkTSpaceContext* pContext, const float fvTangent[], const float fSign, const int iFace,
+                                        const int iVert) -> void {
+        auto vertices = static_cast<VertList*>(pContext->m_pUserData);
+        const size_t i = static_cast<size_t>(iFace) * 3 + static_cast<size_t>(iVert);
+        vertices->operator[](i).tangent.x = fvTangent[0];
+        vertices->operator[](i).tangent.y = fvTangent[1];
+        vertices->operator[](i).tangent.z = fvTangent[2];
+        vertices->operator[](i).tangent.w = fSign;
+    };
+    SMikkTSpaceContext mts_context{};
+    mts_context.m_pInterface = &mts_interface;
+    mts_context.m_pUserData = &vertices;
+
+    bool tan_result = genTangSpaceDefault(&mts_context);
+    if (tan_result == false) throw std::runtime_error("Failed to generate tangents!");
+
+    // generate new vertex and index list without duplicates:
+
+    std::vector<uint32_t> remap_table(vertices.size());   // initialised to zeros
+    std::vector<Vertex> vertex_data_out(vertices.size()); // initialised to zeros
+
+    const int new_vertex_count = WeldMesh(reinterpret_cast<int*>(remap_table.data()), reinterpret_cast<float*>(vertex_data_out.data()), reinterpret_cast<float*>(vertices.data()),
+                                          static_cast<int>(vertices.size()), Vertex::FloatsPerVertex());
+    assert(new_vertex_count >= 0);
+
+    // get new vertices into the vector.
+    // This potentially modifies the size of the input 'vector' argument
+    vertices.resize(static_cast<size_t>(new_vertex_count));
+    for (size_t i = 0; i < static_cast<size_t>(new_vertex_count); ++i) {
+        vertices[i] = vertex_data_out[i];
+    }
+
+    return remap_table;
+}
+
+} // namespace engine::util
\ No newline at end of file
diff --git a/test/res/models/box.glb b/test/res/models/box.glb
new file mode 100644
index 0000000..7b7b8db
Binary files /dev/null and b/test/res/models/box.glb differ
diff --git a/test/src/game.cpp b/test/src/game.cpp
index 4fb9e27..1977e17 100644
--- a/test/src/game.cpp
+++ b/test/src/game.cpp
@@ -81,8 +81,8 @@ void PlayGame(GameSettings settings)
         engine::Entity camera_child = main_scene->CreateEntity("camera_child", camera, glm::vec3{0.0f, 0.0f, -3.0f});
         main_scene->GetTransform(camera_child)->is_static = false;
         auto camren = main_scene->AddComponent<engine::MeshRenderableComponent>(camera_child);
-        camren->visible = true;
-        camren->mesh = GenSphereMesh(app.renderer()->GetDevice(), 1.0f, 16);
+        camren->visible = false;
+        camren->mesh = GenSphereMesh(app.renderer()->GetDevice(), 1.0f, /*16*/32);
         camren->material = app.GetResource<engine::Material>("builtin.default");
 
         /* as of right now, the entity with tag 'camera' is used to build the view
@@ -155,6 +155,12 @@ void PlayGame(GameSettings settings)
 
         engine::Entity tree = engine::util::LoadGLTF(*main_scene, app.GetResourcePath("models/tree.glb"), true);
         main_scene->GetPosition(tree) = glm::vec3{-5.0f, -5.0f, 0.0f};
+
+        engine::Entity box = engine::util::LoadGLTF(*main_scene, app.GetResourcePath("models/box.glb"), true);
+        main_scene->GetPosition(box) = glm::vec3{ -5.0f, -17.0f, 0.1f };
+        main_scene->GetScale(box) *= 10.0f;
+        main_scene->GetRotation(box) = glm::angleAxis(glm::pi<float>(), glm::vec3{ 0.0f, 0.0f, 1.0f });
+        main_scene->GetRotation(box) *= glm::angleAxis(glm::half_pi<float>(), glm::vec3{ 1.0f, 0.0f, 0.0f });
     }
 
     start_scene->GetSystem<CameraControllerSystem>()->next_scene_ = main_scene;
diff --git a/test/src/meshgen.cpp b/test/src/meshgen.cpp
index ebabcb4..2ff2997 100644
--- a/test/src/meshgen.cpp
+++ b/test/src/meshgen.cpp
@@ -7,6 +7,7 @@
 #include <glm/trigonometric.hpp>
 
 #include "resources/mesh.h"
+#include "util/gen_tangents.h"
 
 std::unique_ptr<engine::Mesh> GenSphereMesh(engine::GFXDevice* gfx, float r, int detail, bool wind_inside, bool flip_normals)
 {
@@ -72,7 +73,9 @@ std::unique_ptr<engine::Mesh> GenSphereMesh(engine::GFXDevice* gfx, float r, int
         }
     }
 
-    return std::make_unique<engine::Mesh>(gfx, vertices);
+    std::vector<uint32_t> indices = engine::util::GenTangents(vertices);
+
+    return std::make_unique<engine::Mesh>(gfx, vertices, indices);
 }
 
 std::unique_ptr<engine::Mesh> GenCuboidMesh(engine::GFXDevice* gfx, float x, float y, float z, float tiling, bool wind_inside)
@@ -83,56 +86,58 @@ std::unique_ptr<engine::Mesh> GenCuboidMesh(engine::GFXDevice* gfx, float x, flo
 
     using namespace glm;
 
-    std::vector<engine::Vertex> v{};
+    std::vector<engine::Vertex> vertices{};
 
     // front
-    v.push_back({{0.0f, 0.0f, z}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
-    v.push_back({{0.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, tiling}});
-    v.push_back({{x, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{x, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{x, 0.0f, z}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
-    v.push_back({{0.0f, 0.0f, z}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{0.0f, 0.0f, z}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{0.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, tiling}});
+    vertices.push_back({{x, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{x, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{x, 0.0f, z}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
+    vertices.push_back({{0.0f, 0.0f, z}, {0.0f, -1.0f, 0.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
     // back
-    v.push_back({{x, y, z}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
-    v.push_back({{x, y, 0.0f}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, tiling}});
-    v.push_back({{0.0f, y, 0.0f}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{0.0f, y, 0.0f}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{0.0f, y, z}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
-    v.push_back({{x, y, z}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{x, y, z}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{x, y, 0.0f}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, tiling}});
+    vertices.push_back({{0.0f, y, 0.0f}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{0.0f, y, 0.0f}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{0.0f, y, z}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
+    vertices.push_back({{x, y, z}, {0.0f, 1.0f, 0.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
     // left
-    v.push_back({{0.0f, y, z}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
-    v.push_back({{0.0f, y, 0.0f}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {0.0f, tiling}});
-    v.push_back({{0.0f, 0.0f, 0.0f}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{0.0f, 0.0f, 0.0f}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{0.0f, 0.0f, z}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
-    v.push_back({{0.0f, y, z}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{0.0f, y, z}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{0.0f, y, 0.0f}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {0.0f, tiling}});
+    vertices.push_back({{0.0f, 0.0f, 0.0f}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{0.0f, 0.0f, 0.0f}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{0.0f, 0.0f, z}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
+    vertices.push_back({{0.0f, y, z}, {-1.0f, 0.0f, 0.0f}, {0.0f, -1.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
     // right
-    v.push_back({{x, 0.0f, z}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
-    v.push_back({{x, 0.0f, 0.0f}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {0.0f, tiling}});
-    v.push_back({{x, y, 0.0f}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{x, y, 0.0f}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{x, y, z}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
-    v.push_back({{x, 0.0f, z}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{x, 0.0f, z}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{x, 0.0f, 0.0f}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {0.0f, tiling}});
+    vertices.push_back({{x, y, 0.0f}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{x, y, 0.0f}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{x, y, z}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
+    vertices.push_back({{x, 0.0f, z}, {1.0f, 0.0f, 0.0f}, {0.0f, 1.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
     // top
-    v.push_back({{0.0f, y, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
-    v.push_back({{0.0f, 0.0f, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, tiling}});
-    v.push_back({{x, 0.0f, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{x, 0.0f, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{x, y, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
-    v.push_back({{0.0f, y, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{0.0f, y, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{0.0f, 0.0f, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, tiling}});
+    vertices.push_back({{x, 0.0f, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{x, 0.0f, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{x, y, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
+    vertices.push_back({{0.0f, y, z}, {0.0f, 0.0f, 1.0f}, {1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
     // bottom
-    v.push_back({{x, y, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
-    v.push_back({{x, 0.0f, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, tiling}});
-    v.push_back({{0.0f, 0.0f, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{0.0f, 0.0f, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
-    v.push_back({{0.0f, y, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
-    v.push_back({{x, y, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{x, y, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
+    vertices.push_back({{x, 0.0f, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, tiling}});
+    vertices.push_back({{0.0f, 0.0f, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{0.0f, 0.0f, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, tiling}});
+    vertices.push_back({{0.0f, y, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {tiling, 0.0f}});
+    vertices.push_back({{x, y, 0.0f}, {0.0f, 0.0f, -1.0f}, {-1.0f, 0.0f, 0.0f, 1.0f}, {0.0f, 0.0f}});
 
     if (wind_inside) {
-        for (size_t i = 0; i < v.size(); i += 3) {
-            std::swap(v[i], v[i + 2]);
+        for (size_t i = 0; i < vertices.size(); i += 3) {
+            std::swap(vertices[i], vertices[i + 2]);
         }
     }
 
-    return std::make_unique<engine::Mesh>(gfx, v);
+    std::vector<uint32_t> indices = engine::util::GenTangents(vertices);
+
+    return std::make_unique<engine::Mesh>(gfx, vertices, indices);
 }