Add OpenGL and GLFW dependencies + example

CMakeLists.txt

@@ -3,4 +3,11 @@ project(ecsgame)
 
 set(CMAKE_CXX_STANDARD 17)
 
+find_package(OpenGL REQUIRED)
+find_package(glfw3 REQUIRED)
+
 add_executable(ecsgame main.cpp)
+
+include_directories(${OPENGL_INCLUDE_DIRS})
+
+target_link_libraries(ecsgame ${OPENGL_LIBRARY} glfw)

main.cpp

@@ -1,11 +1,12 @@
 #include <iostream>
 #include "ECS.h"
+#include <GLFW/glfw3.h>
 
 using namespace ECS;
 
-struct Position
+struct Position {
-{
     Position(float x, float y, float z) : x(x), y(y), z(z) {}
+
     Position() : x(0.f), y(0.f), z(0.f) {}
 
     float x;
@@ -13,18 +14,15 @@ struct Position
     float z;
 };
 
-class GravitySystem : public EntitySystem
+class GravitySystem : public EntitySystem {
-{
 public:
-    GravitySystem(float amount)
+    GravitySystem(float amount) {
-    {
         gravityAmount = amount;
     }
 
     virtual ~GravitySystem() {}
 
-    virtual void tick(World* world, float deltaTime) override
+    virtual void tick(World *world, float deltaTime) override {
-    {
         world->each<Position>([&](Entity *ent, ComponentHandle<Position> position) {
             position->y += gravityAmount * deltaTime;
         });
@@ -46,5 +44,35 @@ int main() {
     ComponentHandle<Position> pos = ent->get<Position>();
 
     std::cout << "y position after tick: " << pos->y << std::endl;
+
+    GLFWwindow *window;
+
+    /* Initialize the library */
+    if (!glfwInit())
+        return -1;
+
+    /* Create a windowed mode window and its OpenGL context */
+    window = glfwCreateWindow(640, 480, "Hello World", NULL, NULL);
+    if (!window) {
+        glfwTerminate();
+        return -1;
+    }
+
+    /* Make the window's context current */
+    glfwMakeContextCurrent(window);
+
+    /* Loop until the user closes the window */
+    while (!glfwWindowShouldClose(window)) {
+        /* Render here */
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        /* Swap front and back buffers */
+        glfwSwapBuffers(window);
+
+        /* Poll for and process events */
+        glfwPollEvents();
+    }
+
+    glfwTerminate();
     return 0;
 }