Make train movement smoother

3 files changed, 39 insertions, 14 deletions

diff --git a/src/main.cpp b/src/main.cpp
index b1942c9..4fa5e47 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -85,7 +85,7 @@ int main(int argc, char **argv)
 	Level level(32, 32);
 
 	Bitmap bitmap(Width, Height);
-	TrainCar car(0, 0);
+	TrainCar car;
 
 	int xOffs = 0, yOffs = 0;
 	int xDrag, yDrag;
@@ -123,8 +123,7 @@ int main(int argc, char **argv)
 			float mx = x / Scale + xOffs;
 			float my = y / Scale + yOffs;
 			auto pos = screenToTile({ mx, my });
-			car.x = pos.x;
-			car.y = pos.y;
+            car.setPosition(pos.x, pos.y);
 		}
 	});
 
diff --git a/src/train.cpp b/src/train.cpp
index e369887..046c580 100644
--- a/src/train.cpp
+++ b/src/train.cpp
@@ -9,13 +9,12 @@ void TrainCar::update(Level& level)
 	if (tile == 0)
 		return;
 
-	if (m_progress < 12) {
-		m_progress++;
+	if (m_progress < 1.f) {
+		m_progress += m_speed;
 		return;
 	}
-	else {
-		m_progress = 0;
-	}
+
+	m_progress = 0.f;
 
 	auto n = level.get(x, y - 1);
 	auto e = level.get(x + 1, y);
@@ -42,11 +41,31 @@ void TrainCar::update(Level& level)
 		if (w == SouthEast) m_dir = South;
 		x--;
 	}
+
+    nextTile();
 }
 
 void TrainCar::draw(Bitmap& bitmap, int xo, int yo)
 {
-	int xx = (x - y) * (24 / 2) - xo;
-	int yy = (x + y) * (24 / 4) - yo;
+	float xi = ((float)x + (float)(m_nextX - x) * m_progress) * 24;
+	float yi = ((float)y + (float)(m_nextY - y) * m_progress) * 24;
+	int xx = (int)((xi - yi) / 2.f - (float)xo);
+	int yy = (int)((xi + yi) / 4.f - (float)yo);
 	bitmap.blit(m_sprite, xx, yy, 0, 0, 24, 24);
+}
+
+void TrainCar::setPosition(int tx, int ty)
+{
+    x = tx;
+    y = ty;
+    m_progress = 0.f;
+    nextTile();
+}
+
+void TrainCar::nextTile()
+{
+    if (m_dir == North) { m_nextX = x; m_nextY = y - 1; }
+    if (m_dir == East) { m_nextX = x + 1; m_nextY = y; }
+    if (m_dir == South) { m_nextX = x; m_nextY = y + 1; }
+    if (m_dir == West) { m_nextX = x - 1; m_nextY = y; }
 }
\ No newline at end of file
diff --git a/src/train.h b/src/train.h
index 342c787..05b0da5 100644
--- a/src/train.h
+++ b/src/train.h
@@ -13,15 +13,22 @@ class Level;
 
 class TrainCar {
 public:
-	TrainCar(int x, int y) 
-		: x(x), y(y), m_sprite("../res/car.png") {}
+	TrainCar()
+		: m_sprite("../res/car.png") {}
 
 	void update(Level&);
 	void draw(Bitmap&, int, int);
 
-	int x, y;
+    void setPosition(int x, int y);
 private:
+    void nextTile();
+
 	Bitmap m_sprite;
-	int m_progress{ 0 };
+
+    int x{0}, y{0};
+    float m_speed{0.05f};
+	float m_progress{ 0.f };
+
 	CarDirection m_dir{ North };
+    int m_nextX{0}, m_nextY{0};
 };