complete rewrite

src/main/java/one/oth3r/sit/mixin/TextDisplayDismountMixin.java

@@ -0,0 +1,74 @@
+package one.oth3r.sit.mixin;
+
+import net.minecraft.entity.*;
+import net.minecraft.entity.decoration.DisplayEntity;
+import net.minecraft.util.math.*;
+import net.minecraft.world.World;
+import org.jetbrains.annotations.Nullable;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Unique;
+
+@Mixin(DisplayEntity.TextDisplayEntity.class)
+public class TextDisplayDismountMixin extends DisplayEntity {
+
+    public TextDisplayDismountMixin(EntityType<?> type, World world) {
+        super(type, world);
+    }
+
+    @Override
+    public void refreshData(boolean shouldLerp, float lerpProgress) {}
+
+    @Override
+    public Vec3d updatePassengerForDismount(LivingEntity passenger) {
+        int[][] offset = Dismounting.getDismountOffsets(Direction.NORTH);
+        // new array with another slot
+        int[][] dismountOffsets = new int[offset.length + 1][];
+        // add an empty offset to the start of the array
+        dismountOffsets[0] = new int[]{0, 0};
+        // copy the original elements into the new array starting from index 1
+        System.arraycopy(offset, 0, dismountOffsets, 1, offset.length);
+
+        BlockPos blockPos = this.getBlockPos();
+
+        for (EntityPose entityPose : passenger.getPoses()) {
+            Vec3d vec3d = getDismountPos(passenger, entityPose, dismountOffsets, blockPos);
+
+            // check around the block above
+            if (vec3d == null) vec3d = getDismountPos(passenger, entityPose, dismountOffsets, blockPos.up());
+
+            if (vec3d != null) return vec3d;
+
+        }
+
+        return super.updatePassengerForDismount(passenger);
+    }
+
+    /**
+     * searches around the BlockPos for a stable dismount spot using the dismountOffsets
+     * @param passenger the passenger to check
+     * @param entityPose the pose of the passenger to check
+     * @param dismountOffsets the positions to check around the BlockPos
+     * @param blockPos the BlockPos to check around
+     * @return the Vec3d to dismount at, null if not found
+     */
+    @Unique
+    private @Nullable Vec3d getDismountPos(LivingEntity passenger, EntityPose entityPose, int[][] dismountOffsets, BlockPos blockPos) {
+        // iterate through all dismount offsets
+        for (int[] offset : dismountOffsets) {
+            BlockPos.Mutable mutable = new BlockPos.Mutable();
+            mutable.set(blockPos.getX() + offset[0], blockPos.getY(), blockPos.getZ() + offset[1]);
+
+            double dismountHeight = this.getWorld().getDismountHeight(mutable);
+            if (Dismounting.canDismountInBlock(dismountHeight)) {
+                Vec3d vec3d = Vec3d.ofCenter(mutable, dismountHeight);
+
+                Box boundingBox = passenger.getBoundingBox(entityPose);
+                if (Dismounting.canPlaceEntityAt(this.getWorld(), passenger, boundingBox.offset(vec3d))) {
+                    passenger.setPose(entityPose);
+                    return vec3d;
+                }
+            }
+        }
+        return null;
+    }
+}