Class of static functions to help with ballistic projectile calculations. These functions assume that gravity acts in the y-axis. More...

Static Public Member Functions
static float	ComputeSpeedToReachMaxFlatRange (float range, float gravity_negative, out float timeToLand)
	Given a maximum range (on flat ground) and gravity, what is the maximum speed the projectile can be launched? Use case: The player can only throw grenades with a max range of 30 meters on flat ground. What is the max speed he can throw it? More...

static bool	CanReachTargetWithSpeed (Vector3 startPosition, Vector3 targetPosition, float gravity_negative, float speed)
	Given a start position, gravity and initial speed, can a projectile reach a target position? Use case: If my cannonballs always fire at 200m/sec, can it reach a target position? More...

static bool	ComputeDirectionToHitTargetWithSpeed (Vector3 startPosition, Vector3 targetPosition, float gravity_negative, float speed, out Vector3 direction1, out Vector3 direction2)
	Given a start position, gravity and initial speed, what direction should we fire the projectile to hit a target position? More...

static bool	ComputeTimeToHitGround (Vector3 startPosition, Vector3 velocity, float groundLevel, float gravity_negative, out float timeToHit)
	Given a start position, initial velocity (with direction) and gravity, how much time is needed to reach the ground (at a specified height level). Use case: Artillery has begun firing upon your position. How much time do you have to evacuate / take cover? More...

static Vector3	ComputePositionAtTimeAhead (Vector3 currentPosition, Vector3 velocity, float gravity_negative, float timeAhead)
	Determine what position a projectile will be after a certain time, given its current position and velocity. Use case: To display the trajectory of a grenade before you throw it More...

static Vector3	ComputeVelocityAtTimeAhead (Vector3 currentPosition, Vector3 currentVelocity, float gravity_negative, float timeAhead)
	Determine the velocity of a projectile after a certain time, given its current position and velocity. More...

static Vector3	ComputeVelocityToHitTargetAtTime (Vector3 startPosition, Vector3 targetPosition, float gravity_negative, float timeToTargetPosition)
	Determine the velocity needed to hit a target position in exactly the given amount of time. Use case: you want to fire a catapult projectile to land at a specific position, giving the player exactly 4 seconds of warning time to escape More...

static void	UpdateProjectile (ref Vector3 currentPosition, ref Vector3 currentVelocity, float gravity_negative, float deltaTime)
	Update a projectile's current position and velocity, given the gravity and delta time More...

static float	ComputeGravityToReachTargetWithSpeedAndElevation (float distanceOffset, float heightOffset, float elevationRadians, float speed)
	Determine the gravity needed to reach a target distance and height with a given speed and elevation angle More...

static bool	ComputeSpeedToReachTargetWithElevation (Vector3 startPosition, Vector3 targetPosition, float elevationRadians, float gravity_negative, ref float outSpeed)
	Determine the speed needed to reach a target position given a starting elevation. More...

static bool	ComputeSpeedToReachFlatRangeWithElevation (float elevationRadians, float range, float gravityNegative, out float speed)
	Determine the speed needed to reach a certain range (on flat ground) given a starting elevation More...

static bool	ComputeElevationToHitTargetWithSpeed (float heightOffset, float distanceOffset, float gravityNegative, float speed, bool useSmallerAngle, out float angleRadians)
	Given an initial speed, what elevation angle is needed to hit a target at a specified height offset and flat distance away? More...

Detailed Description

Class of static functions to help with ballistic projectile calculations. These functions assume that gravity acts in the y-axis.

Member Function Documentation

◆ CanReachTargetWithSpeed()

static bool ProjectileHelper.CanReachTargetWithSpeed	(	Vector3	startPosition,
		Vector3	targetPosition,
		float	gravity_negative,
		float	speed
	)

static

Given a start position, gravity and initial speed, can a projectile reach a target position? Use case: If my cannonballs always fire at 200m/sec, can it reach a target position?

Parameters

startPosition	Starting Position of the projectile.
targetPosition	Target Position of the projectile.
gravity_negative	Acceleration due to gravity on y-axis. Should be negative, eg -9.8f
speed	Initial speed of the projectile.

Returns: Returns true if the target position can be reached with the given parameters.

◆ ComputeDirectionToHitTargetWithSpeed()

static bool ProjectileHelper.ComputeDirectionToHitTargetWithSpeed	(	Vector3	startPosition,
		Vector3	targetPosition,
		float	gravity_negative,
		float	speed,
		out Vector3	direction1,
		out Vector3	direction2
	)

static

Given a start position, gravity and initial speed, what direction should we fire the projectile to hit a target position?

Parameters

startPosition	Starting Position of the projectile.
targetPosition	Target Position of the projectile.
gravity_negative	Acceleration due to gravity on y-axis. Should be negative, eg -9.8f
speed	Initial speed of the projectile.
direction1	First possible direction for the projectile
direction2	Second possible direction for the projectile

Returns: Returns true if the target position can be reached with the given parameters.

◆ ComputeElevationToHitTargetWithSpeed()

static bool ProjectileHelper.ComputeElevationToHitTargetWithSpeed	(	float	heightOffset,
		float	distanceOffset,
		float	gravityNegative,
		float	speed,
		bool	useSmallerAngle,
		out float	angleRadians
	)

static

Given an initial speed, what elevation angle is needed to hit a target at a specified height offset and flat distance away?

Parameters

heightOffset	Difference in height of the target from the starting position
distanceOffset	Flat distance away from the starting position.
gravity_negative	Acceleration due to gravity on y-axis. Should be negative, eg -9.8f
speed	Initial speed of the projectile.
useSmallerAngle	Whether to calculate the smaller or larger elevation angle, since two elevations are possible.
angleRadians	Output: the elevation angle needed.

Returns: Returns true if the target can be reached.

◆ ComputeGravityToReachTargetWithSpeedAndElevation()

static float ProjectileHelper.ComputeGravityToReachTargetWithSpeedAndElevation	(	float	distanceOffset,
		float	heightOffset,
		float	elevationRadians,
		float	speed
	)

static

Determine the gravity needed to reach a target distance and height with a given speed and elevation angle

Parameters

distanceOffset	Flat distance away from the starting position.
heightOffset	Height difference from the starting position.
elevationRadians	Elevation angle the projectile will be fired at.
speed	The initial speed of the projectile.

Returns: Returns the necessary gravity to reach the target.

◆ ComputePositionAtTimeAhead()

static Vector3 ProjectileHelper.ComputePositionAtTimeAhead	(	Vector3	currentPosition,
		Vector3	velocity,
		float	gravity_negative,
		float	timeAhead
	)

static

Determine what position a projectile will be after a certain time, given its current position and velocity. Use case: To display the trajectory of a grenade before you throw it

Parameters

currentPosition	Current position of the projectile.
velocity	Current velocity of the projectile.
gravity_negative	Acceleration due to gravity on y-axis. Should be negative, eg -9.8f
timeAhead	The amount of time in the future at which you want to know the position

Returns: Returns the position of the projectile after the specified time.

◆ ComputeSpeedToReachFlatRangeWithElevation()

static bool ProjectileHelper.ComputeSpeedToReachFlatRangeWithElevation	(	float	elevationRadians,
		float	range,
		float	gravityNegative,
		out float	speed
	)

static

Determine the speed needed to reach a certain range (on flat ground) given a starting elevation

Parameters

elevationRadians	Elevation angle the projectile will be fired at.
range	Flat distance away from the starting position.
gravity_negative	Acceleration due to gravity on y-axis. Should be negative, eg -9.8f
speed	Output: Speed of projectile needed to reach the wanted range.

Returns: Returns true if the range can be reached. This could be false, for eg if the elevation is lower than zero.

◆ ComputeSpeedToReachMaxFlatRange()

static float ProjectileHelper.ComputeSpeedToReachMaxFlatRange	(	float	range,
		float	gravity_negative,
		out float	timeToLand
	)

static

Given a maximum range (on flat ground) and gravity, what is the maximum speed the projectile can be launched? Use case: The player can only throw grenades with a max range of 30 meters on flat ground. What is the max speed he can throw it?

Parameters

range	Maximum range of the projectile on flat ground, in meters
gravity_negative	Acceleration due to gravity on y-axis. Should be negative, eg -9.8f
timeToLand	Outputs the time taken for the projectile to reach max range on flat ground. In seconds.

Returns: Returns the speed needed to reach the max range.

◆ ComputeSpeedToReachTargetWithElevation()

static bool ProjectileHelper.ComputeSpeedToReachTargetWithElevation	(	Vector3	startPosition,
		Vector3	targetPosition,
		float	elevationRadians,
		float	gravity_negative,
		ref float	outSpeed
	)

static

Determine the speed needed to reach a target position given a starting elevation.

Parameters

startPosition	Starting position of the projectile.
targetPosition	Target position of the projectile.
elevationRadians	Elevation angle the projectile will be fired at. This should be less than PiBy2 radians, ie 90degrees.
gravity_negative	Acceleration due to gravity on y-axis. Should be negative, eg -9.8f
outSpeed	Output: The calculated speed needed.

Returns: Returns true if the target can be reached with the given elevation, otherwise false

◆ ComputeTimeToHitGround()

static bool ProjectileHelper.ComputeTimeToHitGround	(	Vector3	startPosition,
		Vector3	velocity,
		float	groundLevel,
		float	gravity_negative,
		out float	timeToHit
	)

static

Given a start position, initial velocity (with direction) and gravity, how much time is needed to reach the ground (at a specified height level). Use case: Artillery has begun firing upon your position. How much time do you have to evacuate / take cover?

Parameters

startPosition	Starting position of the projectile.
velocity	Initial velocity of the projectile.
groundLevel	The y-value of the ground level.
gravity_negative	Acceleration due to gravity on y-axis. Should be negative, eg -9.8f
timeToHit	Output: Time to reach the groundlevel specified.

Returns: Returns true if the ground level can be reached with the given parameters.

◆ ComputeVelocityAtTimeAhead()

static Vector3 ProjectileHelper.ComputeVelocityAtTimeAhead	(	Vector3	currentPosition,
		Vector3	currentVelocity,
		float	gravity_negative,
		float	timeAhead
	)

static

Determine the velocity of a projectile after a certain time, given its current position and velocity.

Parameters

currentPosition	Current position of the projectile.
currentVelocity	Current velocity of the projectile.
gravity_negative	Acceleration due to gravity on y-axis. Should be negative, eg -9.8f
timeAhead	The amount of time in the future at which you want to know the velocity

Returns: Returns the velocity of the projectile after the specified time.

◆ ComputeVelocityToHitTargetAtTime()

static Vector3 ProjectileHelper.ComputeVelocityToHitTargetAtTime	(	Vector3	startPosition,
		Vector3	targetPosition,
		float	gravity_negative,
		float	timeToTargetPosition
	)

static

Determine the velocity needed to hit a target position in exactly the given amount of time. Use case: you want to fire a catapult projectile to land at a specific position, giving the player exactly 4 seconds of warning time to escape

Parameters

startPosition	Starting position of the projectile.
targetPosition	Target position of the projectile.
gravity_negative	Acceleration due to gravity on y-axis. Should be negative, eg -9.8f
timeToTargetPosition	The amount of time the projectile should take to reach the target

Returns: Returns the necessary initial velocity of the projectile.

◆ UpdateProjectile()

static void ProjectileHelper.UpdateProjectile	(	ref Vector3	currentPosition,
		ref Vector3	currentVelocity,
		float	gravity_negative,
		float	deltaTime
	)

static

Update a projectile's current position and velocity, given the gravity and delta time

Parameters

currentPosition	Current position of the projectile. Will be modified to give the new position.
currentVelocity	Current velocity of the projectile. Will be modified to give the new velocity.
gravity_negative	Acceleration due to gravity on y-axis. Should be negative, eg -9.8f
deltaTime	The amount of time elapsed since the last update

The documentation for this class was generated from the following file:

ProjectileHelper.cs

Static Public Member Functions

Detailed Description

Member Function Documentation

◆ CanReachTargetWithSpeed()

◆ ComputeDirectionToHitTargetWithSpeed()

◆ ComputeElevationToHitTargetWithSpeed()

◆ ComputeGravityToReachTargetWithSpeedAndElevation()

◆ ComputePositionAtTimeAhead()

◆ ComputeSpeedToReachFlatRangeWithElevation()

◆ ComputeSpeedToReachMaxFlatRange()

◆ ComputeSpeedToReachTargetWithElevation()

◆ ComputeTimeToHitGround()

◆ ComputeVelocityAtTimeAhead()

◆ ComputeVelocityToHitTargetAtTime()

◆ UpdateProjectile()