Merge pull request #4 from TeamOpenIndustry/mc_rails_compat

Add better MC rails compatibility

Author: cam72cam

src/main/java/trackapi/compat/MinecraftRail.java

@@ -9,7 +9,42 @@
 import trackapi.lib.Gauges;
 import trackapi.lib.ITrack;
 
+import java.util.HashMap;
+import java.util.Map;
+
 public class MinecraftRail implements ITrack {
+	private static Map<EnumRailDirection, Vec3d> vectors = new HashMap<>();
+	private static Map<EnumRailDirection, Vec3d> centers = new HashMap<>();
+	static {
+		Vec3d north = new Vec3d(0, 0, 1);
+		Vec3d south = new Vec3d(0, 0, -1);
+		Vec3d east = new Vec3d(1, 0, 0);
+		Vec3d west = new Vec3d(-1, 0, 0);
+		Vec3d ascending = new Vec3d(0, 1, 0);
+
+        vectors.put(EnumRailDirection.ASCENDING_EAST, east.add(ascending).normalize());
+        vectors.put(EnumRailDirection.ASCENDING_NORTH, north.add(ascending).normalize());
+        vectors.put(EnumRailDirection.ASCENDING_SOUTH, south.add(ascending).normalize());
+        vectors.put(EnumRailDirection.ASCENDING_WEST, west.add(ascending).normalize());
+        vectors.put(EnumRailDirection.EAST_WEST, east.normalize());
+        vectors.put(EnumRailDirection.NORTH_EAST, north.add(east).normalize());
+        vectors.put(EnumRailDirection.NORTH_SOUTH, north.normalize());
+        vectors.put(EnumRailDirection.NORTH_WEST, north.add(west).normalize());
+        vectors.put(EnumRailDirection.SOUTH_EAST, south.add(east).normalize());
+        vectors.put(EnumRailDirection.SOUTH_WEST, south.add(west).normalize());
+
+        centers.put(EnumRailDirection.ASCENDING_EAST, new Vec3d(0.5, 0.5, 0.5));
+        centers.put(EnumRailDirection.ASCENDING_NORTH, new Vec3d(0.5, 0.5, 0.5));
+        centers.put(EnumRailDirection.ASCENDING_SOUTH, new Vec3d(0.5, 0.5, 0.5));
+        centers.put(EnumRailDirection.ASCENDING_WEST, new Vec3d(0.5, 0.5, 0.5));
+        centers.put(EnumRailDirection.EAST_WEST, new Vec3d(0.5, 0.1, 0.5));
+        centers.put(EnumRailDirection.NORTH_EAST, new Vec3d(0.75, 0.1, 0.25));
+        centers.put(EnumRailDirection.NORTH_SOUTH, new Vec3d(0.5, 0.1, 0.5));
+        centers.put(EnumRailDirection.NORTH_WEST, new Vec3d(0.25, 0.1, 0.25));
+        centers.put(EnumRailDirection.SOUTH_EAST, new Vec3d(0.75, 0.1, 0.75));
+        centers.put(EnumRailDirection.SOUTH_WEST, new Vec3d(0.25, 0.1, 0.75));
+	}
+
 
 	private EnumRailDirection direction;
 	private BlockPos pos;
@@ -28,32 +63,23 @@ public double getTrackGauge() {
 
 	@Override
 	public Vec3d getNextPosition(Vec3d currentPosition, Vec3d motion) {
-		//TODO fill in the rest of the states
-		
-		switch (direction) {
-		case ASCENDING_EAST:
-			break;
-		case ASCENDING_NORTH:
-			break;
-		case ASCENDING_SOUTH:
-			break;
-		case ASCENDING_WEST:
-			break;
-		case EAST_WEST:
-			return currentPosition.addVector(motion.x > 0 ? motion.lengthVector() : -motion.lengthVector(), 0, pos.getZ() - currentPosition.z + 0.5);
-		case NORTH_EAST:
-			break;
-		case NORTH_SOUTH:
-			return currentPosition.addVector(pos.getX() - currentPosition.x + 0.5, 0, motion.z > 0 ? motion.lengthVector() : -motion.lengthVector());
-		case NORTH_WEST:
-			break;
-		case SOUTH_EAST:
-			break;
-		case SOUTH_WEST:
-			break;
-		}
-		
-		return currentPosition;
+		Vec3d trackMovement = vectors.get(direction);
+		Vec3d trackCenter = centers.get(direction);
+
+		Vec3d posRelativeToCenter = currentPosition.subtractReverse(new Vec3d(pos).add(trackCenter));
+		double distanceToCenter = posRelativeToCenter.lengthVector();
+
+		// Determine if trackMovement should be positive or negative as relative to block center
+		boolean trackPosMotionInverted = posRelativeToCenter.distanceTo(trackMovement) < posRelativeToCenter.scale(-1).distanceTo(trackMovement);
+
+		boolean trackMotionInverted = motion.distanceTo(trackMovement) > motion.scale(-1).distanceTo(trackMovement);
+
+		Vec3d newPosition = new Vec3d(pos).add(trackCenter);
+		//Correct new pos to track alignment
+		newPosition = newPosition.add(trackMovement.scale(trackPosMotionInverted ? -distanceToCenter : distanceToCenter));
+		// Move new pos along track alignment
+		newPosition = newPosition.add(trackMovement.scale(trackMotionInverted ? -motion.lengthVector() : motion.lengthVector()));
+		return newPosition;
 	}
 
 	public static boolean isRail(World world, BlockPos pos) {