From 3dacb0c095d837d2e035308bd824c3a4f35e0ede Mon Sep 17 00:00:00 2001
From: Karl <karl.bittner@hexaquo.at>
Date: Fri, 30 Apr 2021 23:11:01 +0200
Subject: [PATCH] Add ability for client to override fixed and dynamic update

---
 cpp/Application.cpp          |  8 +++-----
 include/Gedeng/Application.h | 22 ++++++++++++++++++++--
 include/Gedeng/Input.h       |  3 ++-
 test/test-app/main.cpp       | 15 +++++++++++++--
 4 files changed, 38 insertions(+), 10 deletions(-)

diff --git a/cpp/Application.cpp b/cpp/Application.cpp
index 723195b..e73cb69 100644
--- a/cpp/Application.cpp
+++ b/cpp/Application.cpp
@@ -9,7 +9,7 @@ namespace Gedeng {
 void Application::run() {
     // Setup Rendering
     // FIXME: Make these parameters variable, maybe move this to a different function
-    RenderBackend::initialize_window(1920, 1080, String("Application"));
+    RenderBackend::initialize_window(WINDOW_SIZE_X, WINDOW_SIZE_Y, WINDOW_NAME);
     Input::initialize(RenderBackend::get_window());
 
     unsigned long previous_time_ms = Time::get_time_ms();
@@ -26,13 +26,11 @@ void Application::run() {
 
         // Update fixed time step
         while (time_until_fixed_update_ms >= MS_PER_UPDATE) {
-            // Fixed Update
-            GG_CORE_INFO("Fixed Update");
+            fixed_update(static_cast<double>(MS_PER_UPDATE) / 1000.0);
             time_until_fixed_update_ms -= MS_PER_UPDATE;
         }
 
-        // Variable update
-        GG_CORE_INFO("Variable Update");
+        dynamic_update(static_cast<double>(elapsed_time_ms) / 1000.0);
     }
 }
 
diff --git a/include/Gedeng/Application.h b/include/Gedeng/Application.h
index d3f737d..05eb7c1 100644
--- a/include/Gedeng/Application.h
+++ b/include/Gedeng/Application.h
@@ -1,18 +1,36 @@
 #pragma once
 
+#include "String.h"
+
 namespace Gedeng {
 
 class Application {
   public:
-    Application() = default;
+    Application(unsigned long ms_per_update, unsigned int window_size_x, unsigned int window_size_y, String window_name)
+        : MS_PER_UPDATE(ms_per_update), WINDOW_SIZE_X(window_size_x), WINDOW_SIZE_Y(window_size_y),
+          WINDOW_NAME(window_name) {
+    }
 
     // Virtual since this class will be inherited by user-created applications
     virtual ~Application() = default;
 
+    // Game Loop
     void run();
 
+    // Primarily for gameplay and physics
+    // To be overridden by client applications
+    virtual void fixed_update(double delta) = 0;
+
+    // Primarily for rendering
+    // To be overridden by client applications
+    virtual void dynamic_update(double delta) = 0;
+
   private:
-    const unsigned long MS_PER_UPDATE = 20;
+    // TODO: These will probably become a separate Settings struct
+    const unsigned long MS_PER_UPDATE;
+    const unsigned int WINDOW_SIZE_X;
+    const unsigned int WINDOW_SIZE_Y;
+    const String WINDOW_NAME;
 };
 
 // To be defined in client applications
diff --git a/include/Gedeng/Input.h b/include/Gedeng/Input.h
index b304615..1212999 100644
--- a/include/Gedeng/Input.h
+++ b/include/Gedeng/Input.h
@@ -17,7 +17,8 @@ class Input {
         glfwSetKeyCallback(window, key_callback);
     }
 
-    // FIXME: Ignore warnings produced by these unused variables -- they're required for the callback to work
+    // FIXME: Ignore warnings produced by these unused variables -- they're required for the callback to work:
+    // https://gcc.gnu.org/onlinedocs/gcc/Diagnostic-Pragmas.html
     static void key_callback(GLFWwindow *window, int key, int scancode, int action, int mods) {
         if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS) glfwSetWindowShouldClose(window, GLFW_TRUE);
 
diff --git a/test/test-app/main.cpp b/test/test-app/main.cpp
index 7d2e221..94172a1 100644
--- a/test/test-app/main.cpp
+++ b/test/test-app/main.cpp
@@ -4,12 +4,23 @@
 
 class TestApp : public Gedeng::Application {
   public:
-    TestApp() = default;
+    TestApp(unsigned long ms_per_update, unsigned int window_size_x, unsigned int window_size_y,
+            Gedeng::String window_name)
+        : Application(ms_per_update, window_size_x, window_size_y, window_name) {
+    }
 
     ~TestApp() = default;
+
+    void fixed_update(double delta) override {
+        GG_CLIENT_INFO("Fixed update");
+    }
+
+    void dynamic_update(double delta) override {
+        GG_CLIENT_INFO("Dynamic update");
+    }
 };
 
 Gedeng::Application *Gedeng::create_application() {
     GG_CLIENT_INFO("Creating Application");
-    return new TestApp();
+    return new TestApp(20, 900, 600, String("Test App"));
 }