Remove global variables.

Global variables are overall bad practice.

src/display.c

@@ -21,11 +21,9 @@
 #ifdef DEBUG
 #	include <stdio.h>
 #endif
-#include <allegro5/allegro.h>
 
-ALLEGRO_DISPLAY *display;
-
-int create_display(unsigned int width, unsigned int height) {
+int create_display(ALLEGRO_DISPLAY *display,
+		unsigned int width, unsigned int height) {
 	display = al_create_display(width, height);
 	if(!display)
 		return 0;
@@ -35,7 +33,7 @@ int create_display(unsigned int width, unsigned int height) {
 	return 1;
 }
 
-void destroy_display() {
+void destroy_display(ALLEGRO_DISPLAY *display) {
 	al_destroy_display(display);
 #ifdef DEBUG
 	puts("Destroyed display.");

src/display.h

@@ -18,17 +18,23 @@
 
 #pragma once
 
+#include <allegro5/allegro.h>
+
 /**
  * @brief Create an allegro 5 display with a given width and height.
  *
+ * @param display The display to create.
  * @param width The width of the display.
  * @param height The height of the display.
  *
  * @return If successful it will return 1, else it will return 0.
  */
-int create_display(unsigned int width, unsigned int height);
+int create_display(ALLEGRO_DISPLAY *display,
+		unsigned int width, unsigned int height);
 
 /**
  * @brief Destroy the display (used for shutdown).
+ *
+ * @param display The display to destroy.
  */
-void destroy_display();
+void destroy_display(ALLEGRO_DISPLAY *display);

src/event_manager.c

@@ -29,7 +29,7 @@ static ALLEGRO_EVENT_QUEUE *event_queue;
 static ALLEGRO_TIMER *timer;
 static int keys[KEY_MAX];
 
-int evnt_mngr_init() {
+int evnt_mngr_init(ALLEGRO_DISPLAY *display) {
 	if(!al_install_keyboard())
 		return 0;
 #ifdef DEBUG

src/event_manager.h

@@ -18,6 +18,8 @@
 
 #pragma once
 
+#include <allegro5/allegro.h>
+
 enum {
 	KEY_UP          = 0x0,
 	KEY_DOWN        = 0x1,
@@ -33,7 +35,7 @@ enum {
  *
  * @return 0 upon failure, 1 upon success.
  */
-int evnt_mngr_init();
+int evnt_mngr_init(ALLEGRO_DISPLAY *display);
 
 /**
  * @brief Deinitialize the event handler.

src/globals.h

@@ -28,8 +28,6 @@
 
 #include <allegro5/allegro.h>
 
-extern ALLEGRO_DISPLAY *display; ///< The allegro display.
-
 extern int redraw; ///< Whether or not to redraw the screen.
 extern int run; ///< Whether or not to continue running the simulation.
 extern int show_help; ///< Whether or not to show the help info.

src/main.c

@@ -43,16 +43,18 @@ int main() {
 		fprintf(stderr, "alleg5: failed to initialize primitives addon.\n");
 		return 1;
 	}
-	if(!create_display(800, 600))
+
+	ALLEGRO_DISPLAY *display;
+	if(!create_display(display, 800, 600))
 	{
 		fprintf(stderr, "alleg5: failed to create display.\n");
 		return 1;
 	}
 
-	if(!evnt_mngr_init())
+	if(!evnt_mngr_init(display))
 	{
 		fprintf(stderr, "alleg5: failed to initialize event queue.\n");
-		destroy_display();
+		destroy_display(display);
 		return 1;
 	}
 
@@ -95,7 +97,7 @@ int main() {
 	}
 
 	evnt_mngr_deinit();
-	destroy_display();
+	destroy_display(display);
 	al_shutdown_primitives_addon();
 #ifdef DEBUG
 	puts("Shutdown primitives addon.");