From 32cdec6b7e89e1755ea62f247331b6f655c83879 Mon Sep 17 00:00:00 2001
From: Sarah Faey <Sarah@witch.gay>
Date: Wed, 7 May 2025 22:52:40 +0200
Subject: [PATCH] cleanes up deltaTime calculation and fps limit

---
 src/Game.cpp | 55 ++++++++++++++++++++++++++++++++++++----------------
 src/Game.h   | 10 ++++++----
 2 files changed, 44 insertions(+), 21 deletions(-)

diff --git a/src/Game.cpp b/src/Game.cpp
index e261d70..a52808a 100644
--- a/src/Game.cpp
+++ b/src/Game.cpp
@@ -14,13 +14,13 @@
 #include "DataStructures/Vector2D.h"
 #include "DataStructures/Hitbox.h"
 
-Game::Game(SDL_Window *window, SDL_Renderer *renderer) 
-    : m_Window(window, SDL_DestroyWindow), 
+Game::Game(SDL_Window *window, SDL_Renderer *renderer) : 
+    m_Player1DirectionInput({ 0,0 }),
+    m_Player2DirectionInput({ 0,0 }),
+    m_Window(window, SDL_DestroyWindow), 
     m_Renderer(renderer, SDL_DestroyRenderer),  
     m_Gamepad1(nullptr, SDL_CloseGamepad),
-    m_TickCount(0),
-    m_Player1DirectionInput({ 0,0 }),
-    m_Player2DirectionInput({ 0,0 })
+    m_Gamepad2(nullptr, SDL_CloseGamepad)
 {
     SDL_FRect player1Hitbox;
     player1Hitbox.x = 0;
@@ -29,6 +29,9 @@ Game::Game(SDL_Window *window, SDL_Renderer *renderer)
     player1Hitbox.h = 20;
     m_Player1 = ActorFactory::CreateMovingActor(Vector2D(0,0), player1Hitbox, player1Hitbox);
 
+    //TODO: read game settings from config file
+    SetFps(60);
+
     //TODO: read keybinds from config if it exists. otherwise initialze standard and write file
     m_KeyboardCommandMap.emplace(SDL_SCANCODE_ESCAPE, new EndGameCommand(this));
     m_KeyboardCommandMap.emplace(SDL_SCANCODE_W, new MoveUpCommand(m_Player1DirectionButtonStatus));
@@ -41,22 +44,12 @@ Game::Game(SDL_Window *window, SDL_Renderer *renderer)
     m_Gamepad1ButtonCommandMap.emplace(SDL_GAMEPAD_BUTTON_DPAD_RIGHT, new MoveRightCommand(m_Player1DirectionButtonStatus));
     m_Gamepad1AxisCommandMap.emplace(SDL_GAMEPAD_AXIS_LEFTX, new MoveXCommand(m_Player1DirectionInput));
     m_Gamepad1AxisCommandMap.emplace(SDL_GAMEPAD_AXIS_LEFTY, new MoveYCommand(m_Player1DirectionInput));
-
 }
 
 void Game::Run()
 {
-    uint64_t currentTicksNS = SDL_GetTicksNS();
-    uint64_t frameTicks = currentTicksNS - m_TickCount;
-    if(frameTicks < m_MinTicksPerFrame)
-    {
-        SDL_DelayNS(m_MinTicksPerFrame - frameTicks);
-        currentTicksNS = SDL_GetTicksNS();
-        frameTicks = currentTicksNS - m_TickCount;
-    }
-	float deltaTime = frameTicks / c_NSPerSecond;
-	m_TickCount = currentTicksNS;
-    long fps = 1/deltaTime;
+    float deltaTime = GetDeltaTime();
+    ulong fps = lround(1/deltaTime);
 
 
     HandleMovement();
@@ -75,6 +68,20 @@ void Game::Run()
     
 }
 
+float Game::GetDeltaTime()
+{
+    uint64_t currentTicksNS = SDL_GetTicksNS();
+    uint64_t frameTicks = currentTicksNS - m_TickCount;
+    if(frameTicks < m_MinTicksPerFrame)
+    {
+        SDL_DelayPrecise(m_MinTicksPerFrame - frameTicks);
+        currentTicksNS = SDL_GetTicksNS();
+        frameTicks = currentTicksNS - m_TickCount;
+    }
+	m_TickCount = currentTicksNS;
+    return frameTicks / c_NSPerSecond;
+}
+
 void Game::HandleMovement()
 {
     NormalizedDirection direction;
@@ -156,6 +163,20 @@ void Game::RemoveGamepad(SDL_JoystickID id)
     }
 }
 
+/// @brief sets the fps limit, 0 = no limit
+/// @param fps 
+void Game::SetFps(uint16_t fps)
+{
+    if(fps == 0)
+    {
+        m_MinTicksPerFrame = 1;
+    }
+    else
+    {
+        m_MinTicksPerFrame = c_NSPerSecond/fps;
+    }
+}
+
 void Game::EndGame() 
 {
     SDL_Event * event = new SDL_Event();
diff --git a/src/Game.h b/src/Game.h
index 5e0ea99..3286d3f 100644
--- a/src/Game.h
+++ b/src/Game.h
@@ -15,20 +15,22 @@ public:
     Game(SDL_Window *window, SDL_Renderer *renderer);
     ~Game() {};
     void Run();
+    float GetDeltaTime();
     void HandleMovement();
     void HandleKeyboardInput(const SDL_Event &event);
     void HandleGamepadButton(const SDL_Event &event);
     void HandleGamepadAxis(const SDL_Event &event);
     void AddGamepad(SDL_JoystickID id);
     void RemoveGamepad(SDL_JoystickID id);
+    void SetFps(uint16_t fps = 0);
     void EndGame();
 private:
-    const float c_GamepadAxisDeadzone = (float)0.2; //TODO: make this a setting?
-    const float c_NSPerSecond = 1000000000;
+    const float c_GamepadAxisDeadzone = 0.2f; //TODO: make this a setting?
+    const float c_NSPerSecond = 1000000000.0f;
 
     bool m_running = true;
     uint64_t m_TickCount = 0;
-    uint64_t m_MinTicksPerFrame = c_NSPerSecond/60;
+    uint64_t m_MinTicksPerFrame;
 
     std::map<SDL_Scancode, GameCommand*> m_KeyboardCommandMap;
     std::map<SDL_GamepadButton, GameCommand*> m_Gamepad1ButtonCommandMap;
@@ -46,7 +48,7 @@ private:
     std::unique_ptr<SDL_Window, decltype(&SDL_DestroyWindow)> m_Window;
     std::unique_ptr<SDL_Renderer, decltype(&SDL_DestroyRenderer)> m_Renderer;
     std::unique_ptr<SDL_Gamepad, decltype(&SDL_CloseGamepad)> m_Gamepad1; 
-    //std::unique_ptr<SDL_Gamepad, decltype(&SDL_CloseGamepad)> m_Gamepad2; 
+    std::unique_ptr<SDL_Gamepad, decltype(&SDL_CloseGamepad)> m_Gamepad2; 
 
 };