Add initial jab at the track API

Author: cam72cam

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

@@ -0,0 +1,78 @@
+package trackapi.compat;
+
+import net.minecraft.block.BlockRailBase;
+import net.minecraft.block.BlockRailBase.EnumRailDirection;
+import net.minecraft.block.state.IBlockState;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.Vec3d;
+import net.minecraft.world.World;
+import trackapi.lib.ITrackTile;
+import trackapi.lib.Util;
+
+public class MinecraftRail implements ITrackTile {
+
+	private EnumRailDirection direction;
+
+	public MinecraftRail(World world, BlockPos pos) {
+		IBlockState state = world.getBlockState(pos);
+        BlockRailBase blockrailbase = (BlockRailBase)state.getBlock();
+        this.direction = blockrailbase.getRailDirection(world, pos, state, null);
+	}
+
+	@Override
+	public double getTrackGauge() {
+		return Util.MINECRAFT_GAUGE;
+	}
+
+	@Override
+	public double getTrackSlope() {
+		return	direction == EnumRailDirection.ASCENDING_EAST ||
+				direction == EnumRailDirection.ASCENDING_WEST ||
+				direction == EnumRailDirection.ASCENDING_NORTH ||
+				direction == EnumRailDirection.ASCENDING_SOUTH ? 1 : 0;
+	}
+
+	@Override
+	public Vec3d getNextPosition(Vec3d currentPosition, float rotationYaw, float bogeyYaw, double distance) {
+		if (distance < 0) {
+			distance = -distance;
+			rotationYaw = (rotationYaw + 180) % 360;
+			bogeyYaw = (bogeyYaw + 180) % 360;
+		}
+		
+		//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:
+			break;
+		case NORTH_EAST:
+			break;
+		case NORTH_SOUTH:
+			if (rotationYaw / 180 == 0) {
+				return currentPosition.addVector(0, 0, distance);
+			}
+			return currentPosition.addVector(0, 0, -distance);
+		case NORTH_WEST:
+			break;
+		case SOUTH_EAST:
+			break;
+		case SOUTH_WEST:
+			break;
+		}
+		
+		return currentPosition;
+	}
+
+	public static boolean isRail(World world, BlockPos pos) {
+		return BlockRailBase.isRailBlock(world, pos);
+	}
+	
+}

src/main/java/trackapi/lib/ITrackTile.java

@@ -0,0 +1,31 @@
+package trackapi.lib;
+
+import net.minecraft.util.math.Vec3d;
+
+public interface ITrackTile {
+	
+	/**
+	 * The distance between the rails measured in meters
+	 * 
+	 * @see Util#STANDARD_GAUGE
+	 * @see Util#MINECRAFT_GAUGE
+	 */
+	public double getTrackGauge();
+	
+	/**
+	 * The slope of the track.  For example, going up 1 meter for every 100 meters in
+	 * length would equal 1/100 or 0.01
+	 */
+	public double getTrackSlope();
+	
+	/**
+	 * Used by rolling stock to look up their next position.
+	 * 
+	 * @param currentPosition - Current entity or bogey position
+	 * @param rotationYaw - Current entity rotation in degrees
+	 * @param bogieYaw - Current bogey rotation in degrees (set to rotationYaw if unused)
+	 * @param distance - Distanced traveled in meters
+	 * @return The new position of the entity or bogey
+	 */
+	public Vec3d getNextPosition(Vec3d currentPosition, float rotationYaw, float bogeyYaw, double distance);
+}

src/main/java/trackapi/lib/Util.java

@@ -0,0 +1,51 @@
+package trackapi.lib;
+
+import net.minecraft.tileentity.TileEntity;
+import net.minecraft.util.math.BlockPos;
+import net.minecraft.util.math.MathHelper;
+import net.minecraft.util.math.Vec3d;
+import net.minecraft.world.World;
+import trackapi.compat.MinecraftRail;
+
+public class Util {
+	/**
+	 * US Standard Gauge in meters
+	 */
+	public static final double STANDARD_GAUGE = 1.435;
+
+	/**
+	 * Minecraft Gauge in meters
+	 */
+	public static final double MINECRAFT_GAUGE = 0.632;
+	
+	private static ITrackTile getInternalTileEntity(World world, Vec3d pos, boolean acceptMinecraftRails) {
+		BlockPos bp = new BlockPos(MathHelper.floor(pos.x), MathHelper.floor(pos.y), MathHelper.floor(pos.z));
+		TileEntity te = world.getTileEntity(bp);
+		if (te instanceof ITrackTile) {
+			return (ITrackTile) te;
+		}
+		if (acceptMinecraftRails) {
+			if (MinecraftRail.isRail(world, bp)) {
+				return new MinecraftRail(world, bp);
+			}
+		}
+		return null;
+	}
+	
+	public static ITrackTile getTileEntity(World world, Vec3d pos, boolean acceptMinecraftRails) {
+		ITrackTile track = getInternalTileEntity(world, pos, acceptMinecraftRails);
+		if (track != null) {
+			return track;
+		}
+		// Allow a bit of vertical fuzziness
+		track = getInternalTileEntity(world, pos.addVector(0, 0.4, 0), acceptMinecraftRails);
+		if (track != null) {
+			return track;
+		}
+		track = getInternalTileEntity(world, pos.addVector(0, -0.4, 0), acceptMinecraftRails);
+		if (track != null) {
+			return track;
+		}
+		return null;
+	}
+}

src/main/resources/pack.mcmeta

@@ -1,6 +1,6 @@
 {
     "pack": {
         "description": "trackapi resources",
-        "pack_format": 3,
+        "pack_format": 3
     }
 }