///
///
/**
* Phaser - Motion
*
* The Motion class contains lots of useful functions for moving game objects around in world space.
*/
module Phaser {
export class Motion {
constructor(game: Game) {
this._game = game;
}
private _game: Game;
/**
* A tween-like function that takes a starting velocity and some other factors and returns an altered velocity.
*
* @param Velocity Any component of velocity (e.g. 20).
* @param Acceleration Rate at which the velocity is changing.
* @param Drag Really kind of a deceleration, this is how much the velocity changes if Acceleration is not set.
* @param Max An absolute value cap for the velocity.
*
* @return The altered Velocity value.
*/
public computeVelocity(Velocity: number, Acceleration: number = 0, Drag: number = 0, Max: number = 10000): number {
if (Acceleration !== 0)
{
Velocity += Acceleration * this._game.time.elapsed;
}
else if (Drag !== 0)
{
var drag: number = Drag * this._game.time.elapsed;
if (Velocity - drag > 0)
{
Velocity = Velocity - drag;
}
else if (Velocity + drag < 0)
{
Velocity += drag;
}
else
{
Velocity = 0;
}
}
if ((Velocity != 0) && (Max != 10000))
{
if (Velocity > Max)
{
Velocity = Max;
}
else if (Velocity < -Max)
{
Velocity = -Max;
}
}
return Velocity;
}
/**
* Given the angle and speed calculate the velocity and return it as a Point
*
* @param angle The angle (in degrees) calculated in clockwise positive direction (down = 90 degrees positive, right = 0 degrees positive, up = 90 degrees negative)
* @param speed The speed it will move, in pixels per second sq
*
* @return A Point where Point.x contains the velocity x value and Point.y contains the velocity y value
*/
public velocityFromAngle(angle: number, speed: number): Point {
if (isNaN(speed))
{
speed = 0;
}
var a: number = this._game.math.degreesToRadians(angle);
return new Point((Math.cos(a) * speed), (Math.sin(a) * speed));
}
/**
* Sets the source Sprite x/y velocity so it will move directly towards the destination Sprite at the speed given (in pixels per second)
* If you specify a maxTime then it will adjust the speed (over-writing what you set) so it arrives at the destination in that number of seconds.
* Timings are approximate due to the way Flash timers work, and irrespective of SWF frame rate. Allow for a variance of +- 50ms.
* The source object doesn't stop moving automatically should it ever reach the destination coordinates.
* If you need the object to accelerate, see accelerateTowardsObject() instead
* Note: Doesn't take into account acceleration, maxVelocity or drag (if you set drag or acceleration too high this object may not move at all)
*
* @param source The Sprite on which the velocity will be set
* @param dest The Sprite where the source object will move to
* @param speed The speed it will move, in pixels per second (default is 60 pixels/sec)
* @param maxTime Time given in milliseconds (1000 = 1 sec). If set the speed is adjusted so the source will arrive at destination in the given number of ms
*/
public moveTowardsObject(source:GameObject, dest:GameObject, speed:number= 60, maxTime:number = 0)
{
var a:number = this.angleBetween(source, dest);
if (maxTime > 0)
{
var d:number = this.distanceBetween(source, dest);
// We know how many pixels we need to move, but how fast?
speed = d / (maxTime / 1000);
}
source.velocity.x = Math.cos(a) * speed;
source.velocity.y = Math.sin(a) * speed;
}
/**
* Sets the x/y acceleration on the source Sprite so it will move towards the destination Sprite at the speed given (in pixels per second)
* You must give a maximum speed value, beyond which the Sprite won't go any faster.
* If you don't need acceleration look at moveTowardsObject() instead.
*
* @param source The Sprite on which the acceleration will be set
* @param dest The Sprite where the source object will move towards
* @param speed The speed it will accelerate in pixels per second
* @param xSpeedMax The maximum speed in pixels per second in which the sprite can move horizontally
* @param ySpeedMax The maximum speed in pixels per second in which the sprite can move vertically
*/
public accelerateTowardsObject(source:GameObject, dest:GameObject, speed:number, xSpeedMax:number, ySpeedMax:number)
{
var a:number = this.angleBetween(source, dest);
source.velocity.x = 0;
source.velocity.y = 0;
source.acceleration.x = Math.cos(a) * speed;
source.acceleration.y = Math.sin(a) * speed;
source.maxVelocity.x = xSpeedMax;
source.maxVelocity.y = ySpeedMax;
}
/**
* Move the given Sprite towards the mouse pointer coordinates at a steady velocity
* If you specify a maxTime then it will adjust the speed (over-writing what you set) so it arrives at the destination in that number of seconds.
* Timings are approximate due to the way Flash timers work, and irrespective of SWF frame rate. Allow for a variance of +- 50ms.
* The source object doesn't stop moving automatically should it ever reach the destination coordinates.
*
* @param source The Sprite to move
* @param speed The speed it will move, in pixels per second (default is 60 pixels/sec)
* @param maxTime Time given in milliseconds (1000 = 1 sec). If set the speed is adjusted so the source will arrive at destination in the given number of ms
*/
public moveTowardsMouse(source:GameObject, speed:number = 60, maxTime:number = 0)
{
var a:number = this.angleBetweenMouse(source);
if (maxTime > 0)
{
var d:number = this.distanceToMouse(source);
// We know how many pixels we need to move, but how fast?
speed = d / (maxTime / 1000);
}
source.velocity.x = Math.cos(a) * speed;
source.velocity.y = Math.sin(a) * speed;
}
/**
* Sets the x/y acceleration on the source Sprite so it will move towards the mouse coordinates at the speed given (in pixels per second)
* You must give a maximum speed value, beyond which the Sprite won't go any faster.
* If you don't need acceleration look at moveTowardsMouse() instead.
*
* @param source The Sprite on which the acceleration will be set
* @param speed The speed it will accelerate in pixels per second
* @param xSpeedMax The maximum speed in pixels per second in which the sprite can move horizontally
* @param ySpeedMax The maximum speed in pixels per second in which the sprite can move vertically
*/
public accelerateTowardsMouse(source:GameObject, speed:number, xSpeedMax:number, ySpeedMax:number)
{
var a:number = this.angleBetweenMouse(source);
source.velocity.x = 0;
source.velocity.y = 0;
source.acceleration.x = Math.cos(a) * speed;
source.acceleration.y = Math.sin(a) * speed;
source.maxVelocity.x = xSpeedMax;
source.maxVelocity.y = ySpeedMax;
}
/**
* Sets the x/y velocity on the source Sprite so it will move towards the target coordinates at the speed given (in pixels per second)
* If you specify a maxTime then it will adjust the speed (over-writing what you set) so it arrives at the destination in that number of seconds.
* Timings are approximate due to the way Flash timers work, and irrespective of SWF frame rate. Allow for a variance of +- 50ms.
* The source object doesn't stop moving automatically should it ever reach the destination coordinates.
*
* @param source The Sprite to move
* @param target The Point coordinates to move the source Sprite towards
* @param speed The speed it will move, in pixels per second (default is 60 pixels/sec)
* @param maxTime Time given in milliseconds (1000 = 1 sec). If set the speed is adjusted so the source will arrive at destination in the given number of ms
*/
public moveTowardsPoint(source:GameObject, target:Point, speed:number = 60, maxTime:number = 0)
{
var a:number = this.angleBetweenPoint(source, target);
if (maxTime > 0)
{
var d:number = this.distanceToPoint(source, target);
// We know how many pixels we need to move, but how fast?
speed = d / (maxTime / 1000);
}
source.velocity.x = Math.cos(a) * speed;
source.velocity.y = Math.sin(a) * speed;
}
/**
* Sets the x/y acceleration on the source Sprite so it will move towards the target coordinates at the speed given (in pixels per second)
* You must give a maximum speed value, beyond which the Sprite won't go any faster.
* If you don't need acceleration look at moveTowardsPoint() instead.
*
* @param source The Sprite on which the acceleration will be set
* @param target The Point coordinates to move the source Sprite towards
* @param speed The speed it will accelerate in pixels per second
* @param xSpeedMax The maximum speed in pixels per second in which the sprite can move horizontally
* @param ySpeedMax The maximum speed in pixels per second in which the sprite can move vertically
*/
public accelerateTowardsPoint(source:GameObject, target:Point, speed:number, xSpeedMax:number, ySpeedMax:number)
{
var a:number = this.angleBetweenPoint(source, target);
source.velocity.x = 0;
source.velocity.y = 0;
source.acceleration.x = Math.cos(a) * speed;
source.acceleration.y = Math.sin(a) * speed;
source.maxVelocity.x = xSpeedMax;
source.maxVelocity.y = ySpeedMax;
}
/**
* Find the distance (in pixels, rounded) between two Sprites, taking their origin into account
*
* @param a The first Sprite
* @param b The second Sprite
* @return int Distance (in pixels)
*/
public distanceBetween(a:GameObject, b:GameObject):number
{
var dx:number = (a.x + a.origin.x) - (b.x + b.origin.x);
var dy:number = (a.y + a.origin.y) - (b.y + b.origin.y);
return this._game.math.vectorLength(dx, dy);
}
/**
* Find the distance (in pixels, rounded) from an Sprite to the given Point, taking the source origin into account
*
* @param a The Sprite
* @param target The Point
* @return int Distance (in pixels)
*/
public distanceToPoint(a:GameObject, target:Point):number
{
var dx:number = (a.x + a.origin.x) - (target.x);
var dy:number = (a.y + a.origin.y) - (target.y);
return this._game.math.vectorLength(dx, dy);
}
/**
* Find the distance (in pixels, rounded) from the object x/y and the mouse x/y
*
* @param a The Sprite to test against
* @return int The distance between the given sprite and the mouse coordinates
*/
public distanceToMouse(a:GameObject):number
{
var dx: number = (a.x + a.origin.x) - this._game.input.x;
var dy: number = (a.y + a.origin.y) - this._game.input.y;
return this._game.math.vectorLength(dx, dy);
}
/**
* Find the angle (in radians) between an Sprite and an Point. The source sprite takes its x/y and origin into account.
* The angle is calculated in clockwise positive direction (down = 90 degrees positive, right = 0 degrees positive, up = 90 degrees negative)
*
* @param a The Sprite to test from
* @param target The Point to angle the Sprite towards
* @param asDegrees If you need the value in degrees instead of radians, set to true
*
* @return Number The angle (in radians unless asDegrees is true)
*/
public angleBetweenPoint(a:GameObject, target:Point, asDegrees:bool = false):number
{
var dx:number = (target.x) - (a.x + a.origin.x);
var dy:number = (target.y) - (a.y + a.origin.y);
if (asDegrees)
{
return this._game.math.radiansToDegrees(Math.atan2(dy, dx));
}
else
{
return Math.atan2(dy, dx);
}
}
/**
* Find the angle (in radians) between the two Sprite, taking their x/y and origin into account.
* The angle is calculated in clockwise positive direction (down = 90 degrees positive, right = 0 degrees positive, up = 90 degrees negative)
*
* @param a The Sprite to test from
* @param b The Sprite to test to
* @param asDegrees If you need the value in degrees instead of radians, set to true
*
* @return Number The angle (in radians unless asDegrees is true)
*/
public angleBetween(a:GameObject, b:GameObject, asDegrees:bool = false):number
{
var dx:number = (b.x + b.origin.x) - (a.x + a.origin.x);
var dy:number = (b.y + b.origin.y) - (a.y + a.origin.y);
if (asDegrees)
{
return this._game.math.radiansToDegrees(Math.atan2(dy, dx));
}
else
{
return Math.atan2(dy, dx);
}
}
/**
* Given the GameObject and speed calculate the velocity and return it as an Point based on the direction the sprite is facing
*
* @param parent The Sprite to get the facing value from
* @param speed The speed it will move, in pixels per second sq
*
* @return An Point where Point.x contains the velocity x value and Point.y contains the velocity y value
*/
public velocityFromFacing(parent:GameObject, speed:number):Point
{
var a:number;
if (parent.facing == Collision.LEFT)
{
a = this._game.math.degreesToRadians(180);
}
else if (parent.facing == Collision.RIGHT)
{
a = this._game.math.degreesToRadians(0);
}
else if (parent.facing == Collision.UP)
{
a = this._game.math.degreesToRadians(-90);
}
else if (parent.facing == Collision.DOWN)
{
a = this._game.math.degreesToRadians(90);
}
return new Point(Math.cos(a) * speed, Math.sin(a) * speed);
}
/**
* Find the angle (in radians) between an Sprite and the mouse, taking their x/y and origin into account.
* The angle is calculated in clockwise positive direction (down = 90 degrees positive, right = 0 degrees positive, up = 90 degrees negative)
*
* @param a The Object to test from
* @param asDegrees If you need the value in degrees instead of radians, set to true
*
* @return Number The angle (in radians unless asDegrees is true)
*/
public angleBetweenMouse(a:GameObject, asDegrees:bool = false):number
{
// In order to get the angle between the object and mouse, we need the objects screen coordinates (rather than world coordinates)
var p:MicroPoint = a.getScreenXY();
var dx:number = a._game.input.x - p.x;
var dy:number = a._game.input.y - p.y;
if (asDegrees)
{
return this._game.math.radiansToDegrees(Math.atan2(dy, dx));
}
else
{
return Math.atan2(dy, dx);
}
}
}
}