DreamRaycast.java

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/*
 * MIT License
 *
 * Copyright (c) 2025 Dreamfire Studio
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */
package com.dreamfirestudios.dreamcore.DreamRaycast;
 
import org.bukkit.FluidCollisionMode;
import org.bukkit.Location;
import org.bukkit.Material;
import org.bukkit.Particle;
import org.bukkit.World;
import org.bukkit.block.Block;
import org.bukkit.entity.Entity;
import org.bukkit.entity.Player;
import org.bukkit.util.RayTraceResult;
import org.bukkit.util.Vector;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
 
import java.util.Objects;
import java.util.Set;
import java.util.function.Predicate;
 
public final class DreamRaycast {
 
    private DreamRaycast() {}
 
    // ===== Types =====================================================================================================
 
    public static final class RaycastHit {
        private final @Nullable Block block;
        private final @Nullable Entity entity;
        private final @Nullable Location hitPosition;
        private final double distance;
 
        public RaycastHit(@Nullable Block block, @Nullable Entity entity, @Nullable Location hitPosition, double distance) {
            this.block = block;
            this.entity = entity;
            this.hitPosition = hitPosition;
            this.distance = distance;
        }
        public @Nullable Block block() { return block; }
        public @Nullable Entity entity() { return entity; }
        public @Nullable Location hitPosition() { return hitPosition; }
        public double distance() { return distance; }
        public boolean hitBlock() { return block != null; }
        public boolean hitEntity() { return entity != null; }
    }
 
    @FunctionalInterface
    public interface PathRenderer {
        void render(@NotNull World world, @NotNull Location point, double t, double max);
    }
 
    // ===== Public convenience wrappers ==============================================================================
 
    public static @Nullable Block rayCastFromPlayerIgnore(Player player, int range, @Nullable Particle particle, Set<Material> ignored) {
        RaycastHit hit = raycast(player, range, 0.0, e -> true, ignored, false,
                particle == null ? null : simpleParticle(particle));
        return hit == null ? null : hit.block();
    }
 
    public static @Nullable Block rayCastFromPlayerMust(Player player, int range, @Nullable Particle particle, Set<Material> mustMatch) {
        RaycastHit hit = raycast(player, range, 0.0, e -> true, mustMatch, true,
                particle == null ? null : simpleParticle(particle));
        return hit == null ? null : hit.block();
    }
 
    public static @Nullable RaycastHit raycastEntities(Player player, double range, double raySize,
                                                       @NotNull Predicate<Entity> entityFilter,
                                                       @Nullable PathRenderer renderer) {
        Objects.requireNonNull(player, "player");
        Objects.requireNonNull(entityFilter, "entityFilter");
        World world = requireWorld(player);
 
        Location start = player.getEyeLocation();
        Vector dir = start.getDirection().normalize();
 
        // Render path (optional)
        if (renderer != null) drawPath(renderer, world, start, dir, range, 0.3);
 
        RayTraceResult ent = world.rayTraceEntities(start, dir, range, raySize, entityFilter);
        if (ent == null || ent.getHitEntity() == null || ent.getHitPosition() == null) return null;
 
        double dist = ent.getHitPosition().toLocation(world).distance(start);
        return new RaycastHit(null, ent.getHitEntity(), ent.getHitPosition().toLocation(world), dist);
    }
 
    public static @Nullable RaycastHit raycast(Player player,
                                               double range,
                                               double raySize,
                                               @NotNull Predicate<Entity> entityFilter,
                                               @NotNull Set<Material> materials,
                                               boolean mustMatch,
                                               @Nullable PathRenderer renderer) {
        Objects.requireNonNull(player, "player");
        Objects.requireNonNull(entityFilter, "entityFilter");
        Objects.requireNonNull(materials, "materials");
        if (range <= 0) throw new IllegalArgumentException("range must be > 0");
        if (raySize < 0) throw new IllegalArgumentException("raySize must be >= 0");
 
        World world = requireWorld(player);
        Location start = player.getEyeLocation();
        Vector dir = start.getDirection().normalize();
 
        // Block hit (respect include/ignore rule)
        RaycastHit blockHit = traceBlocksWithMaterialFilter(world, start, dir, range, materials, mustMatch);
 
        // Entity hit (optional)
        RaycastHit entityHit = null;
        if (raySize > 0.0) {
            RayTraceResult er = world.rayTraceEntities(start, dir, range, raySize, entityFilter);
            if (er != null && er.getHitEntity() != null && er.getHitPosition() != null) {
                double d = er.getHitPosition().toLocation(world).distance(start);
                entityHit = new RaycastHit(null, er.getHitEntity(), er.getHitPosition().toLocation(world), d);
            }
        }
 
        // Choose closest
        RaycastHit chosen = closest(start, blockHit, entityHit);
 
        // Render path (to chosen distance if available; otherwise full range)
        if (renderer != null) {
            double max = chosen == null ? range : chosen.distance();
            drawPath(renderer, world, start, dir, max, 0.3);
        }
 
        return chosen;
    }
 
    // ===== Internals =================================================================================================
 
    private static World requireWorld(Player p) {
        World w = p.getWorld();
        if (w == null) throw new IllegalStateException("Player world is null");
        return w;
    }
 
    private static @Nullable RaycastHit closest(Location start, @Nullable RaycastHit a, @Nullable RaycastHit b) {
        if (a == null) return b;
        if (b == null) return a;
        return a.distance() <= b.distance() ? a : b;
    }
 
    private static @Nullable RaycastHit traceBlocksWithMaterialFilter(World world,
                                                                      Location start,
                                                                      Vector dir,
                                                                      double range,
                                                                      Set<Material> materials,
                                                                      boolean mustMatch) {
        double remaining = range;
        Location cursor = start.clone();
        final double epsilon = 0.01;
 
        while (remaining > 0) {
            RayTraceResult br = world.rayTraceBlocks(
                    cursor, dir, remaining,
                    FluidCollisionMode.NEVER, // ignore fluids by default
                    true                      // ignore passable blocks so we stop on solids
            );
            if (br == null || br.getHitBlock() == null || br.getHitPosition() == null) return null;
 
            Block hit = br.getHitBlock();
            Location pos = br.getHitPosition().toLocation(world);
            double dist = pos.distance(cursor);
 
            boolean inSet = materials.contains(hit.getType());
            if (mustMatch ? inSet : !inSet) {
                double totalDist = start.distance(pos);
                return new RaycastHit(hit, null, pos, totalDist);
            }
 
            // Skip this block and continue from just beyond the hit point
            double advance = Math.max(dist + epsilon, epsilon);
            cursor.add(dir.clone().multiply(advance));
            remaining -= advance;
        }
        return null;
    }
 
    private static void drawPath(PathRenderer renderer, World world, Location start, Vector dir, double maxDistance, double step) {
        Vector unit = dir.clone().normalize();
        double drawn = 0;
        while (drawn <= maxDistance) {
            Location p = start.clone().add(unit.clone().multiply(drawn));
            renderer.render(world, p, drawn, maxDistance);
            drawn += step;
        }
    }
 
    public static PathRenderer simpleParticle(Particle particle) {
        Objects.requireNonNull(particle, "particle");
        return (world, point, t, max) -> world.spawnParticle(particle, point, 1, 0, 0, 0, 0);
    }
}