Code/net/minecraft/world/entity/vehicle/DismountHelper.java

package net.minecraft.world.entity.vehicle;

import java.util.function.Function;
import javax.annotation.Nullable;
import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.tags.BlockTags;
import net.minecraft.world.entity.EntityType;
import net.minecraft.world.entity.LivingEntity;
import net.minecraft.world.entity.Pose;
import net.minecraft.world.level.BlockGetter;
import net.minecraft.world.level.CollisionGetter;
import net.minecraft.world.level.block.TrapDoorBlock;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.phys.AABB;
import net.minecraft.world.phys.Vec3;
import net.minecraft.world.phys.shapes.Shapes;
import net.minecraft.world.phys.shapes.VoxelShape;

public class DismountHelper {
    public static int[][] offsetsForDirection(Direction p_38468_) {
        Direction direction = p_38468_.getClockWise();
        Direction direction1 = direction.getOpposite();
        Direction direction2 = p_38468_.getOpposite();
        return new int[][]{
            {direction.getStepX(), direction.getStepZ()},
            {direction1.getStepX(), direction1.getStepZ()},
            {direction2.getStepX() + direction.getStepX(), direction2.getStepZ() + direction.getStepZ()},
            {direction2.getStepX() + direction1.getStepX(), direction2.getStepZ() + direction1.getStepZ()},
            {p_38468_.getStepX() + direction.getStepX(), p_38468_.getStepZ() + direction.getStepZ()},
            {p_38468_.getStepX() + direction1.getStepX(), p_38468_.getStepZ() + direction1.getStepZ()},
            {direction2.getStepX(), direction2.getStepZ()},
            {p_38468_.getStepX(), p_38468_.getStepZ()}
        };
    }

    public static boolean isBlockFloorValid(double p_38440_) {
        return !Double.isInfinite(p_38440_) && p_38440_ < 1.0;
    }

    public static boolean canDismountTo(CollisionGetter p_38457_, LivingEntity p_38458_, AABB p_38459_) {
        for (VoxelShape voxelshape : p_38457_.getBlockCollisions(p_38458_, p_38459_)) {
            if (!voxelshape.isEmpty()) {
                return false;
            }
        }

        return p_38457_.getWorldBorder().isWithinBounds(p_38459_);
    }

    public static boolean canDismountTo(CollisionGetter p_150280_, Vec3 p_150281_, LivingEntity p_150282_, Pose p_150283_) {
        return canDismountTo(p_150280_, p_150282_, p_150282_.getLocalBoundsForPose(p_150283_).move(p_150281_));
    }

    public static VoxelShape nonClimbableShape(BlockGetter p_38447_, BlockPos p_38448_) {
        BlockState blockstate = p_38447_.getBlockState(p_38448_);
        return !blockstate.is(BlockTags.CLIMBABLE) && (!(blockstate.getBlock() instanceof TrapDoorBlock) || !blockstate.getValue(TrapDoorBlock.OPEN))
            ? blockstate.getCollisionShape(p_38447_, p_38448_)
            : Shapes.empty();
    }

    public static double findCeilingFrom(BlockPos p_38464_, int p_38465_, Function<BlockPos, VoxelShape> p_38466_) {
        BlockPos.MutableBlockPos blockpos$mutableblockpos = p_38464_.mutable();
        int i = 0;

        while (i < p_38465_) {
            VoxelShape voxelshape = p_38466_.apply(blockpos$mutableblockpos);
            if (!voxelshape.isEmpty()) {
                return p_38464_.getY() + i + voxelshape.min(Direction.Axis.Y);
            }

            i++;
            blockpos$mutableblockpos.move(Direction.UP);
        }

        return Double.POSITIVE_INFINITY;
    }

    @Nullable
    public static Vec3 findSafeDismountLocation(EntityType<?> p_38442_, CollisionGetter p_38443_, BlockPos p_38444_, boolean p_38445_) {
        if (p_38445_ && p_38442_.isBlockDangerous(p_38443_.getBlockState(p_38444_))) {
            return null;
        } else {
            double d0 = p_38443_.getBlockFloorHeight(nonClimbableShape(p_38443_, p_38444_), () -> nonClimbableShape(p_38443_, p_38444_.below()));
            if (!isBlockFloorValid(d0)) {
                return null;
            } else if (p_38445_ && d0 <= 0.0 && p_38442_.isBlockDangerous(p_38443_.getBlockState(p_38444_.below()))) {
                return null;
            } else {
                Vec3 vec3 = Vec3.upFromBottomCenterOf(p_38444_, d0);
                AABB aabb = p_38442_.getDimensions().makeBoundingBox(vec3);

                for (VoxelShape voxelshape : p_38443_.getBlockCollisions(null, aabb)) {
                    if (!voxelshape.isEmpty()) {
                        return null;
                    }
                }

                if (p_38442_ != EntityType.PLAYER
                    || !p_38443_.getBlockState(p_38444_).is(BlockTags.INVALID_SPAWN_INSIDE) && !p_38443_.getBlockState(p_38444_.above()).is(BlockTags.INVALID_SPAWN_INSIDE)) {
                    return !p_38443_.getWorldBorder().isWithinBounds(aabb) ? null : vec3;
                } else {
                    return null;
                }
            }
        }
    }
}