Implement sprite depth sorting

This algorithm draws the level in two passes; the ground and rail tiles
are drawn first, then the train cars and walls. This method isn't
perfect, but it'll do for now.

1 files changed, 7 insertions, 0 deletions

diff --git a/src/train.cpp b/src/train.cpp
index cfbae97..080a357 100644
--- a/src/train.cpp
+++ b/src/train.cpp
@@ -57,6 +57,13 @@ void Train::setPosition(int tx, int ty)
 	findNextTile();
 }
 
+Point2D Train::getSpritePosition() const
+{
+	int xi = ceil((float)x + (float)(m_nextX - x) * m_progress);
+	int yi = ceil((float)y + (float)(m_nextY - y) * m_progress);
+	return { xi, yi };
+}
+
 void Train::addVehicle(Train* newTrain)
 {
 	if (!m_prev) {