Add a game timerHEADmaster

This adds a delta time that ensures that everything moves at the same
speed regardless of framerate or system.

5 files changed, 13 insertions, 7 deletions

diff --git a/src/level.cpp b/src/level.cpp
index 22f861b..43ca215 100644
--- a/src/level.cpp
+++ b/src/level.cpp
@@ -32,10 +32,10 @@ void Level::set(int x, int y, uint8_t tile)
 		m_tiles[x + y * m_width] = tile;
 }
 
-void Level::update()
+void Level::update(float deltaTime)
 {
 	for (const auto& vehicle : m_vehicles) {
-		vehicle->update();
+		vehicle->update(deltaTime);
 	}
 }
 
diff --git a/src/level.h b/src/level.h
index fa6376d..c706b06 100644
--- a/src/level.h
+++ b/src/level.h
@@ -36,7 +36,7 @@ public:
 	void set(int x, int y, uint8_t tile);
 	bool inBounds(int x, int y) const { return x >= 0 && x < m_width && y >= 0 && y < m_height; }
 
-	void update();
+	void update(float deltaTime);
 	void draw(Bitmap& bitmap, int xo, int yo);
 
 	void addVehicle(int x, int y);
diff --git a/src/main.cpp b/src/main.cpp
index 25e6fea..b417b45 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -5,6 +5,7 @@
 #include "window.h"
 
 #include <SDL_keycode.h>
+#include <chrono>
 
 int main(int argc, char** argv)
 {
@@ -107,7 +108,12 @@ int main(int argc, char** argv)
 		}
 	});
 
+	auto lastTime = std::chrono::high_resolution_clock::now();
 	while (!window.shouldClose()) {
+		auto now = std::chrono::high_resolution_clock::now();
+		float deltaTime = std::chrono::duration_cast<std::chrono::duration<float>>(now - lastTime).count() * 100;
+		lastTime = now;
+
 		window.update();
 		bitmap.clear(0xff224466);
 
@@ -116,7 +122,7 @@ int main(int argc, char** argv)
 		if (left) xOffs -= cameraMoveSpeed;
 		if (right) xOffs += cameraMoveSpeed;
 
-		level.update();
+		level.update(deltaTime);
 		level.draw(bitmap, xOffs, yOffs);
 
 		int xx = (hoveredTile.x - hoveredTile.y) * (TileSize / 2) - xOffs;
diff --git a/src/train.cpp b/src/train.cpp
index 43ebe8a..8507af0 100644
--- a/src/train.cpp
+++ b/src/train.cpp
@@ -7,7 +7,7 @@
 
 static const Bitmap SPRITES("res/car.png");
 
-void Train::update()
+void Train::update(float deltaTime)
 {
 	if (m_next) {
 		m_speed = m_next->m_speed;
@@ -20,7 +20,7 @@ void Train::update()
 
 	m_speed *= m_acceleration;
 	if (m_progress < 1.f) {
-		m_progress += m_speed;
+		m_progress += m_speed * deltaTime;
 		return;
 	}
 
diff --git a/src/train.h b/src/train.h
index c496db8..9e064df 100644
--- a/src/train.h
+++ b/src/train.h
@@ -10,7 +10,7 @@ public:
 	explicit Train(Level& level)
 		: m_level(level) { }
 
-	void update();
+	void update(float deltaTime);
 	void draw(Bitmap&, int, int);
 
 	void setPosition(int x, int y);