Package nokunami.floral_warfare.common.entity.projectile

Class TrajectoryUtil

java.lang.Object

nokunami.floral_warfare.common.entity.projectile.TrajectoryUtil

public final class TrajectoryUtil
extends Object

TrajectoryUtil — projectile trajectory helpers for Minecraft Forge 1.20.1 Minecraft projectile physics recap: - Each tick: velocity *= drag, then velocity.y -= gravity - Default arrow: drag = 0.99, gravity = 0.05 (per tick) - Default snowball/egg: drag = 0.99, gravity = 0.03 - Fireball: drag = 0.95, gravity = 0.0 - ThrownPotion: drag = 0.99, gravity = 0.05 All positions are in blocks (doubles). Time is measured in ticks.

Field Summary

Fields

Modifier and Type	Field	Description
static final double	DRAG_FIREBALL
static final double	DRAG_NORMAL
static final double	GRAVITY_ARROW
static final double	GRAVITY_NONE
static final double	GRAVITY_THROWABLE

Method Summary

Modifier and Type	Method	Description
static net.minecraft.world.phys.Vec3	aimArrow(net.minecraft.world.phys.Vec3 shooterEye, net.minecraft.world.phys.Vec3 target, double power)	Aim an arrow at a target given a power multiplier (0.0–1.0 → 0–3 blocks/tick).
static net.minecraft.world.phys.Vec3	calculateAimVelocity(net.minecraft.world.phys.Vec3 shooterEye, net.minecraft.world.phys.Vec3 target, double speed, double drag, double gravity, int maxTicks)	Calculates the launch velocity needed to hit a target position, given a fixed projectile speed (magnitude) and physics constants.
static net.minecraft.world.phys.Vec3	getEyePosition(net.minecraft.world.entity.Entity entity)	Returns the eye-level position of an entity as a Vec3, convenient as the launch origin for projectiles.
static net.minecraft.world.phys.Vec3	getImpactPosition(net.minecraft.world.phys.Vec3 origin, net.minecraft.world.phys.Vec3 velocity, double drag, double gravity, double targetY, int maxTicks)	Returns only the final landing position (Y ≤ targetY) or the position after maxTicks if the projectile never reaches that height.
static net.minecraft.world.phys.Vec3[]	simulateArrow(net.minecraft.world.phys.Vec3 origin, net.minecraft.world.phys.Vec3 velocity, int maxTicks)	Simulate an arrow (drag=0.99, gravity=0.05).
static net.minecraft.world.phys.Vec3[]	simulatePath(net.minecraft.world.phys.Vec3 origin, net.minecraft.world.phys.Vec3 velocity, double drag, double gravity, int maxTicks)	Simulates a projectile step-by-step and returns the position at each tick.
static net.minecraft.world.phys.Vec3[]	simulateThrowable(net.minecraft.world.phys.Vec3 origin, net.minecraft.world.phys.Vec3 velocity, int maxTicks)	Simulate a thrown snowball / egg / potion (drag=0.99, gravity=0.03).
static net.minecraft.world.phys.Vec3	velocityFromAngles(double yawRad, double pitchRad, double speed)	Builds a velocity vector from yaw/pitch angles and a speed scalar.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

GRAVITY_ARROW

public static final double GRAVITY_ARROW

See Also:

• Constant Field Values

GRAVITY_THROWABLE

public static final double GRAVITY_THROWABLE

See Also:

• Constant Field Values

GRAVITY_NONE

public static final double GRAVITY_NONE

See Also:

• Constant Field Values

DRAG_NORMAL

public static final double DRAG_NORMAL

See Also:

• Constant Field Values

DRAG_FIREBALL

public static final double DRAG_FIREBALL

See Also:

• Constant Field Values

Method Details

simulatePath

public static net.minecraft.world.phys.Vec3[] simulatePath(net.minecraft.world.phys.Vec3 origin,
 net.minecraft.world.phys.Vec3 velocity,
 double drag,
 double gravity,
 int maxTicks)

Simulates a projectile step-by-step and returns the position at each tick.

Parameters:

origin - starting position (block coords)

velocity - initial velocity vector (blocks/tick)

drag - velocity multiplier applied each tick (e.g. 0.99)

gravity - downward acceleration applied each tick (e.g. 0.05)

maxTicks - maximum number of ticks to simulate

Returns:

array of positions, index 0 = origin (tick 0)

getImpactPosition

public static net.minecraft.world.phys.Vec3 getImpactPosition(net.minecraft.world.phys.Vec3 origin,
 net.minecraft.world.phys.Vec3 velocity,
 double drag,
 double gravity,
 double targetY,
 int maxTicks)

Returns only the final landing position (Y ≤ targetY) or the position after maxTicks if the projectile never reaches that height.

Parameters:

origin - launch position

velocity - initial velocity

drag - per-tick drag coefficient

gravity - per-tick downward acceleration

targetY - Y level considered "ground" (stop condition)

maxTicks - safety cap

Returns:

estimated impact position

calculateAimVelocity

public static net.minecraft.world.phys.Vec3 calculateAimVelocity(net.minecraft.world.phys.Vec3 shooterEye,
 net.minecraft.world.phys.Vec3 target,
 double speed,
 double drag,
 double gravity,
 int maxTicks)

Calculates the launch velocity needed to hit a target position, given a fixed projectile speed (magnitude) and physics constants. Uses a binary-search approach on the pitch angle to find a solution. Returns null if no valid arc exists within the given constraints.

Parameters:

shooterEye - position of the shooter's eye (launch point)

target - position to hit

speed - scalar speed of the projectile (blocks/tick)

drag - per-tick drag coefficient

gravity - per-tick gravity

maxTicks - maximum flight time to consider

Returns:

velocity vector to launch the projectile, or null

simulateArrow

public static net.minecraft.world.phys.Vec3[] simulateArrow(net.minecraft.world.phys.Vec3 origin,
 net.minecraft.world.phys.Vec3 velocity,
 int maxTicks)

Simulate an arrow (drag=0.99, gravity=0.05).

simulateThrowable

public static net.minecraft.world.phys.Vec3[] simulateThrowable(net.minecraft.world.phys.Vec3 origin,
 net.minecraft.world.phys.Vec3 velocity,
 int maxTicks)

Simulate a thrown snowball / egg / potion (drag=0.99, gravity=0.03).

aimArrow

public static net.minecraft.world.phys.Vec3 aimArrow(net.minecraft.world.phys.Vec3 shooterEye,
 net.minecraft.world.phys.Vec3 target,
 double power)

Aim an arrow at a target given a power multiplier (0.0–1.0 → 0–3 blocks/tick).

getEyePosition

public static net.minecraft.world.phys.Vec3 getEyePosition(net.minecraft.world.entity.Entity entity)

Returns the eye-level position of an entity as a Vec3, convenient as the launch origin for projectiles.

velocityFromAngles

public static net.minecraft.world.phys.Vec3 velocityFromAngles(double yawRad,
 double pitchRad,
 double speed)

Builds a velocity vector from yaw/pitch angles and a speed scalar. Angles should be in radians.

Parameters:

yawRad - horizontal angle (0 = south / +Z)

pitchRad - vertical angle (negative = upward in standard math, but Minecraft stores pitch inverted; pass raw look angle)

speed - magnitude in blocks/tick