Error handling, Keyboard input, Shader stuff

EventHandler.cpp

@@ -1,9 +1,32 @@
 #include "EventHandler.h"
 
-void EventHandler::handleEvents(GLFWwindow *window) {
+bool EventHandler::wireFrameMode = 0;
+
+EventHandler::EventHandler(GLFWwindow *p_window)
+    : window(p_window) {
+
+    glfwSetKeyCallback(window, key_callback);
+
+}
+
+void EventHandler::handleEvents() {
     glfwPollEvents();
 
     if(glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
         glfwSetWindowShouldClose(window, true);
+
 }
 
+void EventHandler::key_callback(GLFWwindow *p_window, int key, int scancode, int action, int mods) {
+    // Silence warnings of unused variables.
+    (void)p_window; (void)scancode; (void)mods;
+
+    if (key == GLFW_KEY_O && action == GLFW_PRESS) {
+        wireFrameMode = !wireFrameMode;
+        if(wireFrameMode) {
+            glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+        } else {
+            glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+        }
+    }
+}