Quick and simple multi-car train implementation

3 files changed, 43 insertions, 8 deletions

diff --git a/src/main.cpp b/src/main.cpp
index c19d4e3..0dd2dea 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -15,7 +15,10 @@ int main(int argc, char** argv)
 
 	Level level(32, 32, tiles);
 	Bitmap bitmap(Width, Height);
-	Train car(level);
+	Train engine(level);
+	Train wagon(level);
+
+	engine.addVehicle(&wagon);
 
 	int xOffs = 0, yOffs = 0;
 	int xDrag, yDrag;
@@ -37,7 +40,7 @@ int main(int argc, char** argv)
 			int mx = x / Scale + xOffs;
 			int my = y / Scale + yOffs;
 			auto pos = ScreenToTile({ mx, my });
-			car.setPosition(pos.x, pos.y);
+			engine.setPosition(pos.x, pos.y);
 		}
 	});
 
@@ -63,8 +66,11 @@ int main(int argc, char** argv)
 		bitmap.clear(0xff224466);
 
 		level.draw(bitmap, xOffs, yOffs);
-		car.update(level);
-		car.draw(bitmap, xOffs, yOffs);
+		engine.update(level);
+		engine.draw(bitmap, xOffs, yOffs);
+
+		wagon.update(level);
+		wagon.draw(bitmap, xOffs, yOffs);
 
 		int xx = (hoveredTile.x - hoveredTile.y) * (TileSize / 2) - xOffs;
 		int yy = (hoveredTile.x + hoveredTile.y) * (TileSize / 4) - yOffs;
diff --git a/src/train.cpp b/src/train.cpp
index 98a493f..2604898 100644
--- a/src/train.cpp
+++ b/src/train.cpp
@@ -5,15 +5,29 @@
 
 void Train::update(Level& level)
 {
-	auto tile = level.get(x, y);
-	if (tile == 0)
-		return;
+	if (m_next) {
+		m_speed = m_next->m_speed;
+		m_progress = m_next->m_progress;
+	} else {
+		auto tile = level.get(x, y);
+		if (tile == 0)
+			return;
+	}
 
 	if (m_progress < 1.f) {
 		m_progress += m_speed;
 		return;
 	}
 
+	if (m_next) {
+		x = m_nextX;
+		y = m_nextY;
+		m_nextX = m_next->x;
+		m_nextY = m_next->y;
+		m_progress = 0.f;
+		findDirection();
+	}
+
 	setPosition(m_nextX, m_nextY);
 }
 
@@ -40,6 +54,16 @@ void Train::setPosition(int tx, int ty)
 	findNextTile();
 }
 
+void Train::addVehicle(Train* newTrain)
+{
+	if (!m_prev) {
+		m_prev = newTrain;
+		newTrain->m_next = this;
+	} else {
+		m_prev->addVehicle(newTrain);
+	}
+}
+
 void Train::findDirection()
 {
 	auto tile = m_level.get(x, y);
@@ -81,4 +105,4 @@ void Train::findNextTile()
 		m_nextX = x - 1;
 		m_nextY = y;
 	}
-}
\ No newline at end of file
+}
diff --git a/src/train.h b/src/train.h
index dc09889..9663150 100644
--- a/src/train.h
+++ b/src/train.h
@@ -14,11 +14,16 @@ public:
 	void draw(Bitmap&, int, int);
 
 	void setPosition(int x, int y);
+	// Add a vehicle to the end of this train
+	void addVehicle(Train*);
 
 private:
 	void findDirection();
 	void findNextTile();
 
+	Train* m_next { nullptr };
+	Train* m_prev { nullptr };
+
 	Bitmap m_sprite;
 	Level& m_level;