Fix Windows build

FindGLM now properly searches newer glm packages which
doesn't include a "include" folder.

CMakeLists.txt

@@ -21,7 +21,7 @@ add_executable(raytracer
     src/main.cpp
     src/scene.cpp)
 target_include_directories(raytracer PUBLIC include PRIVATE ${GLM_INCLUDE_DIR})
-target_link_libraries(raytracer PUBLIC stb SDL2::Core imgui glad)
+target_link_libraries(raytracer PUBLIC stb SDL2::Main imgui glad)
 set_target_properties(raytracer PROPERTIES
     CXX_STANDARD 17
     CXX_STANDARD_REQUIRED YES

cmake/FindGLM.cmake

@@ -25,6 +25,7 @@ if (WIN32)
         PATHS
         $ENV{PROGRAMFILES}/include
         ${GLM_ROOT_DIR}/include
+        ${GLM_ROOT_DIR}
         DOC "The directory where glm/glm.hpp resides")
 else()
     # Find include files

src/scene.cpp

@@ -1,6 +1,7 @@
 #include "scene.h"
 
 #include <glm/gtx/perpendicular.hpp>
+#include <functional>
 
 constexpr double pi = 3.14159265358979323846l;
 
@@ -112,6 +113,8 @@ Node<T>* find_hit_ray_search(Node<T>& node, const Ray ray, std::vector<Node<T>*>
             out->push_back(&node);
         }
     }
+
+    return nullptr;
 }
 
 template<typename T>
@@ -161,7 +164,7 @@ std::tuple<glm::vec3, glm::vec3> orthogonal_system(const glm::vec3& v1) {
 
 glm::vec3 hemisphere(const double u1, const double u2) {
     const double r = sqrt(1.0 - u1 * u1);
-    const double phi = 2 * M_PI * u2;
+    const double phi = 2 * pi * u2;
     
     return glm::vec3(cos(phi) * r, sin(phi) * r, u1);
 }