How to move a sprite forward - Revision history

SebNozzi at 20:01, 20 November 2021

2021-11-20T20:01:35Z

JoeStrout at 13:58, 6 March 2020

2020-03-06T13:58:42Z

JoeStrout: Created page with "Move a sprite in its "forward" direction (i.e. in the +X direction when the sprite is not rotated) by using the cos and sin functions, as shown below. Note that cos..."

2020-03-06T13:56:48Z

Created page with "Move a sprite in its "forward" direction (i.e. in the +X direction when the sprite is not rotated) by using the cos and sin functions, as shown below. Note that cos..."

New page

Move a sprite in its "forward" direction (i.e. in the +X direction when the sprite is not rotated) by using the [[cos]] and [[sin]] functions, as shown below. Note that [[cos]] and [[sin]] require an angle in radians, while [[Sprite.rotation]] is in degrees. Convert from degrees to radians by multiplying by [[pi]]/180.

== Example ==
This example moves a sprite in its forward direction, now and then changing to a new random direction. (If the sprite wanders off the screen, just press Control-C to stop the program, and run again.)

This could be combined with [[How to point a sprite at a target]] to make the sprite chase a target (such as the mouse).

<ms>clear
sp = new Sprite
sp.image = file.loadImage("/sys/pics/arrows/arrow2.png")
sp.x = 300
sp.y = 320
display(4).sprites.push sp
speed = 2 // (pixels per frame)
while true // (press Control-C to exit)
if rnd < 0.01 then sp.rotation = 360*rnd
ang = sp.rotation * pi/180
sp.x = sp.x + cos(ang) * speed
sp.y = sp.y + sin(ang) * speed
yield
end while</ms>

[[Category:Mini Micro]]
[[Category:How To]]

← Older revision		Revision as of 20:01, 20 November 2021
Line 1:		Line 1:
−	Move a sprite in its "forward" direction (i.e. in the +X direction when the sprite is not rotated) by using the [[cos]] and [[sin]] functions, as shown below. Note that [[cos]] and [[sin]] require an angle in radians, while [[Sprite.rotation]] is in degrees. Convert from degrees to radians by multiplying by [[pi]]/180.	+	Move a [[Sprite\|sprite]] in its "forward" direction (i.e. in the +X direction when the sprite is not rotated) by using the [[cos]] and [[sin]] functions, as shown below. Note that [[cos]] and [[sin]] require an angle in radians, while [[Sprite.rotation]] is in degrees. Convert from degrees to radians by multiplying by [[pi]]/180.

	If "forward" for your sprite is not oriented to the right in the unrotated sprite image, then simply add some constant (e.g. 90) to the sprite rotation before converting to degrees. The same can be done to make a sprite move left or right relative to whatever way it is facing. To move backwards, you could either add 180 degrees, or simply use a negative speed.		If "forward" for your sprite is not oriented to the right in the unrotated sprite image, then simply add some constant (e.g. 90) to the sprite rotation before converting to degrees. The same can be done to make a sprite move left or right relative to whatever way it is facing. To move backwards, you could either add 180 degrees, or simply use a negative speed.

← Older revision		Revision as of 13:58, 6 March 2020
Line 1:		Line 1:
	Move a sprite in its "forward" direction (i.e. in the +X direction when the sprite is not rotated) by using the [[cos]] and [[sin]] functions, as shown below. Note that [[cos]] and [[sin]] require an angle in radians, while [[Sprite.rotation]] is in degrees. Convert from degrees to radians by multiplying by [[pi]]/180.		Move a sprite in its "forward" direction (i.e. in the +X direction when the sprite is not rotated) by using the [[cos]] and [[sin]] functions, as shown below. Note that [[cos]] and [[sin]] require an angle in radians, while [[Sprite.rotation]] is in degrees. Convert from degrees to radians by multiplying by [[pi]]/180.
		+
		+	If "forward" for your sprite is not oriented to the right in the unrotated sprite image, then simply add some constant (e.g. 90) to the sprite rotation before converting to degrees. The same can be done to make a sprite move left or right relative to whatever way it is facing. To move backwards, you could either add 180 degrees, or simply use a negative speed.

	== Example ==		== Example ==