minecraft-src/net/minecraft/world/entity/ai/control/MoveControl.java

package net.minecraft.world.entity.ai.control;

import net.minecraft.core.BlockPos;
import net.minecraft.core.Direction;
import net.minecraft.tags.BlockTags;
import net.minecraft.util.Mth;
import net.minecraft.world.entity.Mob;
import net.minecraft.world.entity.ai.attributes.Attributes;
import net.minecraft.world.entity.ai.navigation.PathNavigation;
import net.minecraft.world.level.block.state.BlockState;
import net.minecraft.world.level.pathfinder.NodeEvaluator;
import net.minecraft.world.level.pathfinder.PathType;
import net.minecraft.world.phys.shapes.VoxelShape;

public class MoveControl implements Control {
	public static final float MIN_SPEED = 5.0E-4F;
	public static final float MIN_SPEED_SQR = 2.5000003E-7F;
	protected static final int MAX_TURN = 90;
	protected final Mob mob;
	protected double wantedX;
	protected double wantedY;
	protected double wantedZ;
	protected double speedModifier;
	protected float strafeForwards;
	protected float strafeRight;
	protected MoveControl.Operation operation = MoveControl.Operation.WAIT;

	public MoveControl(Mob mob) {
		this.mob = mob;
	}

	/**
	 * @return If the mob is currently trying to go somewhere
	 */
	public boolean hasWanted() {
		return this.operation == MoveControl.Operation.MOVE_TO;
	}

	public double getSpeedModifier() {
		return this.speedModifier;
	}

	/**
	 * Sets the speed and location to move to
	 */
	public void setWantedPosition(double x, double y, double z, double speed) {
		this.wantedX = x;
		this.wantedY = y;
		this.wantedZ = z;
		this.speedModifier = speed;
		if (this.operation != MoveControl.Operation.JUMPING) {
			this.operation = MoveControl.Operation.MOVE_TO;
		}
	}

	public void strafe(float forward, float strafe) {
		this.operation = MoveControl.Operation.STRAFE;
		this.strafeForwards = forward;
		this.strafeRight = strafe;
		this.speedModifier = 0.25;
	}

	public void tick() {
		if (this.operation == MoveControl.Operation.STRAFE) {
			float f = (float)this.mob.getAttributeValue(Attributes.MOVEMENT_SPEED);
			float g = (float)this.speedModifier * f;
			float h = this.strafeForwards;
			float i = this.strafeRight;
			float j = Mth.sqrt(h * h + i * i);
			if (j < 1.0F) {
				j = 1.0F;
			}

			j = g / j;
			h *= j;
			i *= j;
			float k = Mth.sin(this.mob.getYRot() * (float) (Math.PI / 180.0));
			float l = Mth.cos(this.mob.getYRot() * (float) (Math.PI / 180.0));
			float m = h * l - i * k;
			float n = i * l + h * k;
			if (!this.isWalkable(m, n)) {
				this.strafeForwards = 1.0F;
				this.strafeRight = 0.0F;
			}

			this.mob.setSpeed(g);
			this.mob.setZza(this.strafeForwards);
			this.mob.setXxa(this.strafeRight);
			this.operation = MoveControl.Operation.WAIT;
		} else if (this.operation == MoveControl.Operation.MOVE_TO) {
			this.operation = MoveControl.Operation.WAIT;
			double d = this.wantedX - this.mob.getX();
			double e = this.wantedZ - this.mob.getZ();
			double o = this.wantedY - this.mob.getY();
			double p = d * d + o * o + e * e;
			if (p < 2.5000003E-7F) {
				this.mob.setZza(0.0F);
				return;
			}

			float n = (float)(Mth.atan2(e, d) * 180.0F / (float)Math.PI) - 90.0F;
			this.mob.setYRot(this.rotlerp(this.mob.getYRot(), n, 90.0F));
			this.mob.setSpeed((float)(this.speedModifier * this.mob.getAttributeValue(Attributes.MOVEMENT_SPEED)));
			BlockPos blockPos = this.mob.blockPosition();
			BlockState blockState = this.mob.level().getBlockState(blockPos);
			VoxelShape voxelShape = blockState.getCollisionShape(this.mob.level(), blockPos);
			if (o > this.mob.maxUpStep() && d * d + e * e < Math.max(1.0F, this.mob.getBbWidth())
				|| !voxelShape.isEmpty()
					&& this.mob.getY() < voxelShape.max(Direction.Axis.Y) + blockPos.getY()
					&& !blockState.is(BlockTags.DOORS)
					&& !blockState.is(BlockTags.FENCES)) {
				this.mob.getJumpControl().jump();
				this.operation = MoveControl.Operation.JUMPING;
			}
		} else if (this.operation == MoveControl.Operation.JUMPING) {
			this.mob.setSpeed((float)(this.speedModifier * this.mob.getAttributeValue(Attributes.MOVEMENT_SPEED)));
			if (this.mob.onGround() || this.mob.isInLiquid() && this.mob.isAffectedByFluids()) {
				this.operation = MoveControl.Operation.WAIT;
			}
		} else {
			this.mob.setZza(0.0F);
		}
	}

	/**
	 * @return true if the mob can walk successfully to a given X and Z
	 */
	private boolean isWalkable(float relativeX, float relativeZ) {
		PathNavigation pathNavigation = this.mob.getNavigation();
		if (pathNavigation != null) {
			NodeEvaluator nodeEvaluator = pathNavigation.getNodeEvaluator();
			if (nodeEvaluator != null
				&& nodeEvaluator.getPathType(this.mob, BlockPos.containing(this.mob.getX() + relativeX, this.mob.getBlockY(), this.mob.getZ() + relativeZ))
					!= PathType.WALKABLE) {
				return false;
			}
		}

		return true;
	}

	/**
	 * Attempt to rotate the first angle to become the second angle, but only allow overall direction change to at max be third parameter
	 */
	protected float rotlerp(float sourceAngle, float targetAngle, float maximumChange) {
		float f = Mth.wrapDegrees(targetAngle - sourceAngle);
		if (f > maximumChange) {
			f = maximumChange;
		}

		if (f < -maximumChange) {
			f = -maximumChange;
		}

		float g = sourceAngle + f;
		if (g < 0.0F) {
			g += 360.0F;
		} else if (g > 360.0F) {
			g -= 360.0F;
		}

		return g;
	}

	public double getWantedX() {
		return this.wantedX;
	}

	public double getWantedY() {
		return this.wantedY;
	}

	public double getWantedZ() {
		return this.wantedZ;
	}

	protected static enum Operation {
		WAIT,
		MOVE_TO,
		STRAFE,
		JUMPING;
	}
}