force view

gistfile1.txt

import net.minestom.server.MinecraftServer;
import net.minestom.server.collision.BoundingBox;
import net.minestom.server.collision.CollisionUtils;
import net.minestom.server.collision.PhysicsResult;
import net.minestom.server.coordinate.Pos;
import net.minestom.server.coordinate.Vec;
import net.minestom.server.entity.Entity;
import net.minestom.server.entity.EntityType;
import net.minestom.server.entity.PlayerExtended;
import net.minestom.server.event.player.PlayerPacketEvent;
import net.minestom.server.network.packet.client.play.ClientPlayerRotationPacket;
import net.minestom.server.network.packet.client.play.ClientSteerVehiclePacket;
import net.minestom.server.timer.TaskSchedule;
import net.worldseed.contexts.ItemContext;
import net.worldseed.entities.WorldSeedFakePlayer;
import net.worldseed.regions.RegionAction;
import net.worldseed.regions.WorldSeedInstance;

import java.util.List;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicBoolean;

public class ForcedViewHandler {
    private final PlayerExtended player;
    private AtomicBoolean active = new AtomicBoolean(false);
    private double distance = 5;

    private Pos pos = null;
    private Entity viewing = null;

    private float yaw, pitch;

    private static final BoundingBox cameraBoundingBox = new BoundingBox(0.5, 0.5, 0.5, new Pos(0, 1.5, 0));

    private List<RegionAction> onJump;
    private List<RegionAction> onSneak;

    public ForcedViewHandler(PlayerExtended player) {
        this.player = player;

        player.eventNode().addListener(PlayerPacketEvent.class, (event) -> {
            if (active.get()) {
                if (event.getPacket() instanceof ClientPlayerRotationPacket rotation) {
                    updateView(rotation.yaw(), rotation.pitch());
                }

                if (event.getPacket() instanceof ClientSteerVehiclePacket packet) {
                    var fakePlayer = player.getFakePlayer();

                    if (fakePlayer != null && player.getInstance() instanceof WorldSeedInstance wsi) {
                        if (fakePlayer.isSneaking() && packet.flags() == 0) {
                            fakePlayer.setSneaking(false);
                        } else if (!fakePlayer.isSneaking() && packet.flags() == 2) {
                            fakePlayer.setSneaking(true);

                            var context = new ItemContext<>(wsi, player, null);
                            if (onSneak != null) player.getExecutor().executeActions(onSneak, context, UUID.randomUUID(), List.of());
                        } else if (player.isOnGround() && packet.flags() == 1) {
                            var context = new ItemContext<>(wsi, player, null);
                            if (onJump != null) player.getExecutor().executeActions(onJump, context, UUID.randomUUID(), List.of());
                        }
                    }
                }
            }
        });
    }

    public void setPositionView(Pos p) {
        this.pos = p;

        if (!active.get()) {
            active.set(true);
            start();
        }
    }

    public void stopView() {
        if (viewing != null) {
            player.teleport(player.getFakePlayer().getPosition().withView(yaw, pitch)).thenRun(() -> {
                player.stopSpectating();
                viewing.removePassenger(player);
                viewing.remove();
                viewing = null;
                onJump = null;
                onSneak = null;
                active.set(false);
                player.setInvisible(false);
            });

            player.getFakePlayer().remove();
            player.setFakePlayer(null);
        }
    }

    private void start() {
        if (active.get()) stopView();
        if (!(player.getInstance() instanceof WorldSeedInstance wsi)) return;

        this.viewing = new Entity(EntityType.ZOMBIE);

        viewing.setNoGravity(true);
        viewing.setHasPhysics(false);
        viewing.setHasCollision(false);
        viewing.setInvisible(true);

        this.yaw = 180-pos.yaw();
        this.pitch = pos.pitch();

        viewing.setInstance(player.getInstance(), player.getPosition().sub(0, 1.5, 0).withView(-pos.yaw(), pos.pitch())).thenRun(() -> {
            MinecraftServer.getSchedulerManager().scheduleTask(() -> {
                player.setInvisible(true);

                viewing.addPassenger(player);
                player.spectate(viewing);
            }, TaskSchedule.tick(4), TaskSchedule.stop());

            var fakePlayer = new WorldSeedFakePlayer(player, wsi, player.getPosition(), 4);
            player.setFakePlayer(fakePlayer);

            fakePlayer.setHasPhysics(true);
            fakePlayer.setNoGravity(false);

            redraw();
        });
    }

    private void updateView(float yaw, float pitch) {
        this.yaw = 180-yaw;
        this.pitch = pitch;

        redraw();
    }

    private void redraw() {
        if (viewing == null) return;
        if (pos == null) return;

        double pr = Math.toRadians(yaw);
        double yr = Math.toRadians(pitch);

        final double xz = Math.cos(yr);

        double x = xz * Math.sin(pr) * distance + pos.x();
        double y = Math.sin(yr) * distance + pos.y() - 1.5;
        double z = xz * Math.cos(pr) * distance + pos.z();

        Vec desiredPos = new Vec(x, y, z);
        PhysicsResult result = CollisionUtils.handlePhysics(player.getInstance(), player.getInstance().getChunkAt(pos), cameraBoundingBox, pos, desiredPos.sub(pos), null, true);

        viewing.setView(180 - yaw, pitch);
        viewing.teleport(result.newPosition().withView(180 - yaw, pitch));

        if (player.getFakePlayer() != null) player.getFakePlayer().setView(180 - yaw, pitch);
    }

    public void setSneakHandler(List<RegionAction> actionListSneak) {
        this.onSneak = actionListSneak;
    }

    public void setJumpHandler(List<RegionAction> actionListJump) {
        this.onJump = actionListJump;
    }

    public void setDistanceView(double distance) {
        this.distance = distance;
    }
}