Moving Sprites on a Curve/s has me totally upside down

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GreekToMe

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Joined: 27th Oct 2009

Location: Colorado

Posted: 13th Mar 2020 14:24

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Hi,
This is hopefully easy for a lot of you. It could create some interesting stimulating discussion. (may be?)
I have been long "mystified" with some sprite moving techniques. I have invested a lot of hours trying to figure things out to no avail. I can move sprites in all directions and in all formations (as in space invaders etc). I can move them and also rotate them at the same time, either with or without offset. I have spent a lot of time with interpolation and Bezier curves. As a separate issue for me, I can make "free curves", as in S curves etc using the Bezier curve formulas/formulae (which one is correct?

), but I cannot figure out how to make a sprite follow the curve created.
And then again, I am not sure this is the right approach.

How do they do the sprite movement as indicated in the following links?
The early 80s Galaga game
https://www.youtube.com/watch?v=dvjapcHsqXY&t=195s
The 1982 AppGameKit game. You can see the particular sprite movement at about 55 seconds. The figure eight and or random curve movement. The rest of the stuff with bouncing of the walls etc, I can do with some work.
https://www.youtube.com/watch?v=zyhwHEsQJcM

Well, help, suggestions, ideas and what not, are WELCOME!
Cheers!

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Mesher

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Posted: 13th Mar 2020 14:41 Edited at: 13th Mar 2020 14:42

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Maybe useful to take a look into CreateTweenSprite and CreateTweenChain and all the other lovely Tween commands available - i did something with tweens long time ago and worked well.

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GreekToMe

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Posted: 13th Mar 2020 15:33

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@Mesher, You know, I have looked at "tweening" briefly and didn't seem at the time that was an avenue which could bring solutions. Now, I am on it again, and see where I get. Thanks and
Cheers!

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Mesher

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Posted: 13th Mar 2020 15:55 Edited at: 13th Mar 2020 16:16

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Unless you create your own method

by using an array of paths points using the X/Y coords in an array and move the sprite to each point in turn in that array.

If ya know my meaning.

Ill see what i can do after work. I can quickly knock something up for you to take a look at.

EDIT

Something like this

// Project: sprite mover 
// Created: 2020-03-13

// show all errors
SetErrorMode(2)
#constant screenwidth=1024
#constant screenheight= 768
// set window properties
SetWindowTitle( "sprite mover" )
SetWindowSize( 1024, 768, 0 )
SetWindowAllowResize( 1 ) // allow the user to resize the window

// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 ) // since version 2.0.22 we can use nicer default fonts

type _Points
	x#
	y#
endtype
points as _Points[]
point as _Points

// lets create a circle in the centre of the screen for a sprite to follow
for a=0 to 360 step 10
	point.x# = screenwidth / 2 + 10 * sin(a)
	point.y# = screenheight / 2 + 10 * cos(a)
	points.insert(point)
next

spr = CreateSprite(0)

currentpoint=0
do
	SetSpritePosition(spr,points[currentpoint].x#, points[currentpoint].y#)
	inc currentpoint
	if currentpoint>points.length then currentpoint=0

Print( ScreenFPS() )
    Sync()
loop

+ Code Snippet


// Project: sprite mover 
// Created: 2020-03-13

// show all errors
SetErrorMode(2)
#constant screenwidth=1024
#constant screenheight= 768
// set window properties
SetWindowTitle( "sprite mover" )
SetWindowSize( 1024, 768, 0 )
SetWindowAllowResize( 1 ) // allow the user to resize the window

// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 ) // since version 2.0.22 we can use nicer default fonts

type _Points
	x#
	y#
endtype
points as _Points[]
point as _Points


// lets create a circle in the centre of the screen for a sprite to follow
for a=0 to 360 step 10
	point.x# = screenwidth / 2 + 10 * sin(a)
	point.y# = screenheight / 2 + 10 * cos(a)
	points.insert(point)
next


spr = CreateSprite(0)

	

currentpoint=0
do
	SetSpritePosition(spr,points[currentpoint].x#, points[currentpoint].y#)
	inc currentpoint
	if currentpoint>points.length then currentpoint=0
	


    Print( ScreenFPS() )
    Sync()
loop

Moves a sprite along points thats been added to an array - this creates a set of points in a style of a clock.

Or this creates a style of a figure of 8

// Project: sprite mover 
// Created: 2020-03-13

// show all errors
SetErrorMode(2)
#constant screenwidth=1024
#constant screenheight= 768
// set window properties
SetWindowTitle( "sprite mover" )
SetWindowSize( 1024, 768, 0 )
SetWindowAllowResize( 1 ) // allow the user to resize the window

// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 ) // since version 2.0.22 we can use nicer default fonts

type _Points
	x#
	y#
endtype
points as _Points[]
point as _Points

// lets create a circle in the centre of the screen for a sprite to follow
for a=0 to 360 step 10
	point.x# = screenwidth / 2 + 100 * sin(a) + cos(a)
	point.y# = screenheight / 2 + 100 * cos(a) * sin(a)
	points.insert(point)
next

spr = CreateSprite(0)

currentpoint=0
do
	SetSpritePosition(spr,points[currentpoint].x#, points[currentpoint].y#)
	inc currentpoint
	if currentpoint>points.length then currentpoint=0

Print( ScreenFPS() )
    Sync()
loop

+ Code Snippet


// Project: sprite mover 
// Created: 2020-03-13

// show all errors
SetErrorMode(2)
#constant screenwidth=1024
#constant screenheight= 768
// set window properties
SetWindowTitle( "sprite mover" )
SetWindowSize( 1024, 768, 0 )
SetWindowAllowResize( 1 ) // allow the user to resize the window

// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 ) // since version 2.0.22 we can use nicer default fonts

type _Points
	x#
	y#
endtype
points as _Points[]
point as _Points


// lets create a circle in the centre of the screen for a sprite to follow
for a=0 to 360 step 10
	point.x# = screenwidth / 2 + 100 * sin(a) + cos(a)
	point.y# = screenheight / 2 + 100 * cos(a) * sin(a)
	points.insert(point)
next


spr = CreateSprite(0)

	

currentpoint=0
do
	SetSpritePosition(spr,points[currentpoint].x#, points[currentpoint].y#)
	inc currentpoint
	if currentpoint>points.length then currentpoint=0
	


    Print( ScreenFPS() )
    Sync()
loop

Hope this helps for now

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GreekToMe

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Joined: 27th Oct 2009

Location: Colorado

Posted: 13th Mar 2020 16:25

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@Mesher. Awesome! I will look at it shortly. Should you take the time to add more then...

Cheers!

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Mesher

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Posted: 13th Mar 2020 16:26

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This creates a snake.

// Project: sprite mover 
// Created: 2020-03-13

// show all errors
SetErrorMode(2)
#constant screenwidth=1024
#constant screenheight= 768
// set window properties
SetWindowTitle( "sprite mover" )
SetWindowSize( 1024, 768, 0 )
SetWindowAllowResize( 1 ) // allow the user to resize the window

// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 ) // since version 2.0.22 we can use nicer default fonts

type _Points
	x#
	y#
endtype
points as _Points[]
point as _Points

// lets create a circle in the centre of the screen for a sprite to follow
for a=0 to 360 step 5
	point.x# = screenwidth / 2 + 100 * sin(a) - cos(a)
	point.y# = screenheight / 2 + 100 * cos(a) * sin(a)
	points.insert(point)
next

spr as integer[5]
for a=0 to 4
	spr[a] = CreateSprite(0)

currentpoint=0
do
	for a=0 to 4
		if currentpoint-a>0 then SetSpritePosition(spr[a],points[currentpoint-a].x#, points[currentpoint-a].y#)
	next
		
		inc currentpoint
	if currentpoint>points.length then currentpoint=0

Print( ScreenFPS() )
    Sync()
loop

+ Code Snippet


// Project: sprite mover 
// Created: 2020-03-13

// show all errors
SetErrorMode(2)
#constant screenwidth=1024
#constant screenheight= 768
// set window properties
SetWindowTitle( "sprite mover" )
SetWindowSize( 1024, 768, 0 )
SetWindowAllowResize( 1 ) // allow the user to resize the window

// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 ) // since version 2.0.22 we can use nicer default fonts

type _Points
	x#
	y#
endtype
points as _Points[]
point as _Points


// lets create a circle in the centre of the screen for a sprite to follow
for a=0 to 360 step 5
	point.x# = screenwidth / 2 + 100 * sin(a) - cos(a)
	point.y# = screenheight / 2 + 100 * cos(a) * sin(a)
	points.insert(point)
next

spr as integer[5]
for a=0 to 4
	spr[a] = CreateSprite(0)

next
	

currentpoint=0
do
	for a=0 to 4
		if currentpoint-a>0 then SetSpritePosition(spr[a],points[currentpoint-a].x#, points[currentpoint-a].y#)
	next
		
		inc currentpoint
	if currentpoint>points.length then currentpoint=0
	


    Print( ScreenFPS() )
    Sync()
loop

Have fun...

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GreekToMe

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Joined: 27th Oct 2009

Location: Colorado

Posted: 13th Mar 2020 16:31

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@Mesher
BTW if you are new to the community..WELCOME!!!!
Glad to have you!

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GreekToMe

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Location: Colorado

Posted: 13th Mar 2020 17:07

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@Mesher,
Sometimes we get involved in a project with the wrong approach and we fail to see the simple solution, or portion of it. So, we get stuck deeper and deeper in code and never get anywhere.
Today I decided to stop working on Interpolation, both linear and circular, along with Bezier curves, sit back, catch up a bit on my sleep and ponder. Yes,stupidity abounds!
Then, the light bulb lit up. Quit being stubborn and ask for help! Help is an amazing thing!
I should have done it about 80 hrs of code writing earlier!
You gave me plenty to get started!
I am ever so Thankful!
Cheers!

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Mesher

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Posted: 13th Mar 2020 18:02

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Its always useful to see how others would acheive things. Thats how we learn new ways of doing things.

Your more than welcome, hope you find this technique useful.

It can be useful for many things:-

Asteroids
Centepede
Snake

or anything similar

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GreekToMe

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Location: Colorado

Posted: 13th Mar 2020 18:34

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@Mesher. Roger that!
Thanks again!
Cheers!

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Mesher

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Posted: 13th Mar 2020 18:38

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My version of a Beizer in AGK

// Project: sprite mover 
// Created: 2020-03-13

// show all errors
SetErrorMode(2)
#constant screenwidth=1024
#constant screenheight= 768
// set window properties
SetWindowTitle( "sprite mover" )
SetWindowSize( 1024, 768, 0 )
SetWindowAllowResize( 1 ) // allow the user to resize the window

// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 ) // since version 2.0.22 we can use nicer default fonts

type _Points
	x#
	y#
endtype
global points as _Points[]
global point as _Points
global spr as integer[]

// Beizer

// create 3 points that is statically positioned on screen
p1x#=10
p1y#=10

p2x#=screenwidth/2
p2y#=screenheight

p3x#=screenwidth-10
p3y#=10

createBeizer(4,p1x#,p1y#,p2x#,p2y#,p3x#,p3y#,0)

spr.insert(CreateSprite(0))

currentpoint=0
c=MakeColor(255,255,255)
do
	print(points.length)

for a=0 to points.length-2
		DrawLine(points[a].x#,points[a].y#,points[a+1].x#,points[a+1].y#,c,c)
		DrawLine(points[a+1].x#,points[a+1].y#,points[a+2].x#,points[a+2].y#,c,c)
	next
	
	SetSpritePosition(spr[0],points[currentpoint].x#, points[currentpoint].y#)
		
	inc currentpoint
	if currentpoint>points.length then currentpoint=0

Print( ScreenFPS() )
    Sync()
    sleep(100)
loop

function createBeizer(n, p1x#,p1y#, p2x#, p2y#, p3x#, p3y#,b)
// insert points
	point.x# = p1x#
	point.y# = p1y#
	points.insert(point)

/*	point.x# = p2x#
	point.y# = p2y#
	points.insert(point)

point.x# = p3x#
	point.y# = p3y#
	points.insert(point)
*/

//calculate new step

if n>0
		
		p12x# = (p1x# + p2x#) / 2.0
		p12y# = (p1y# + p2y#) / 2.0
		
		p23x# = (p2x# + p3x#) / 2.0
		p23y# = (p2y# + p3y#) / 2.0
		
		p123x# = (p12x# + p23x#) / 2.0
		p123y# = (p12y# + p23y#) / 2.0
		
		
		createBeizer(n-1,p1x#,p1y#,p12x#,p12y#,p123x#,p123y#,b+3)
		createBeizer(n-1,p123x#,p123y#,p23x#,p23y#,p3x#,p3y#,b+3)
		
	endif
	
endfunction

+ Code Snippet


// Project: sprite mover 
// Created: 2020-03-13

// show all errors
SetErrorMode(2)
#constant screenwidth=1024
#constant screenheight= 768
// set window properties
SetWindowTitle( "sprite mover" )
SetWindowSize( 1024, 768, 0 )
SetWindowAllowResize( 1 ) // allow the user to resize the window

// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 ) // since version 2.0.22 we can use nicer default fonts

type _Points
	x#
	y#
endtype
global points as _Points[]
global point as _Points
global spr as integer[]


// Beizer

// create 3 points that is statically positioned on screen
p1x#=10
p1y#=10

p2x#=screenwidth/2
p2y#=screenheight

p3x#=screenwidth-10
p3y#=10

createBeizer(4,p1x#,p1y#,p2x#,p2y#,p3x#,p3y#,0)

spr.insert(CreateSprite(0))

currentpoint=0
c=MakeColor(255,255,255)
do
	print(points.length)

	for a=0 to points.length-2
		DrawLine(points[a].x#,points[a].y#,points[a+1].x#,points[a+1].y#,c,c)
		DrawLine(points[a+1].x#,points[a+1].y#,points[a+2].x#,points[a+2].y#,c,c)
	next
	
	SetSpritePosition(spr[0],points[currentpoint].x#, points[currentpoint].y#)
		
	inc currentpoint
	if currentpoint>points.length then currentpoint=0
	


    Print( ScreenFPS() )
    Sync()
    sleep(100)
loop

function createBeizer(n, p1x#,p1y#, p2x#, p2y#, p3x#, p3y#,b)
// insert points
	point.x# = p1x#
	point.y# = p1y#
	points.insert(point)

/*	point.x# = p2x#
	point.y# = p2y#
	points.insert(point)

	point.x# = p3x#
	point.y# = p3y#
	points.insert(point)
*/

//calculate new step

	if n>0
		
		p12x# = (p1x# + p2x#) / 2.0
		p12y# = (p1y# + p2y#) / 2.0
		
		p23x# = (p2x# + p3x#) / 2.0
		p23y# = (p2y# + p3y#) / 2.0
		
		p123x# = (p12x# + p23x#) / 2.0
		p123y# = (p12y# + p23y#) / 2.0
		
		
		createBeizer(n-1,p1x#,p1y#,p12x#,p12y#,p123x#,p123y#,b+3)
		createBeizer(n-1,p123x#,p123y#,p23x#,p23y#,p3x#,p3y#,b+3)
		
	endif
	
endfunction

Its rubbish i know

Increase the N in the function from 4 to what ever for detail

Line 42

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blink0k

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Posted: 13th Mar 2020 20:35 Edited at: 13th Mar 2020 20:35

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I did an experiment with a galaga game once. I found the simplest way to control the movement was with a string of instructions (S-Straight, L-Left, R-Right) with an accompanying distance or angle. Not super accurate but it worked out ok for me.

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Raven

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Location: Hertfordshire, England

Posted: 14th Mar 2020 05:46

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Generally speaking the "Paths" that Enemies had in Old School Shoot 'em Up Games was essentially a hardcoded Formula.

#CONSTANT TRUE					0xFF
#CONSTANT FALSE					0x00

#CONSTANT SIZEOF_IMAGE_HEADER 	12
#CONSTANT SIZEOF_INTEGER			4

#CONSTANT DEVICEWIDTH			640
#CONSTANT DEVICEHEIGHT			480
#CONSTANT DEVICEDEPTH			32
#CONSTANT DEVICEPITCH			(640 * 4)

SETWINDOWSIZE( DEVICEWIDTH, DEVICEHEIGHT, FALSE )
SETSYNCRATE( 0, TRUE )

GLOBAL RENDERBUFFER, RENDERTARGET AS INTEGER
RENDERBUFFER = CREATEMEMBLOCK( SIZEOF_IMAGE_HEADER + (DEVICEWIDTH * DEVICEHEIGHT * SIZEOF_INTEGER) )
			   SETMEMBLOCKINT( RENDERBUFFER, 0, DEVICEWIDTH )
			   SETMEMBLOCKINT( RENDERBUFFER, 4, DEVICEHEIGHT )
			   SETMEMBLOCKINT( RENDERBUFFER, 8, DEVICEDEPTH )
RENDERTARGET = CREATEOBJECTQUAD()

GLOBAL XOLD, YOLD, X, Y AS INTEGER

XOLD = 1
YOLD = 300

REPEAT
	IF X > DEVICEWIDTH
		CLEAR_SCREEN( 0xFF000000 )
		X = 0
	ENDIF
	IF Y > DEVICEHEIGHT
		Y = 0
	ENDIF
	DRAW_PIXEL( X, 50 + 20 * SIN( X * 2 ), MAKECOLOR( 255, 255, 255 ) )
	DRAW_PIXEL( 50 + 20 * SIN(Y * 2), Y, MAKECOLOR( 128, 128, 128 ) )
	INC X
	INC Y
	
	DRAW_SCREEN()
UNTIL GETRAWKEYPRESSED(27)

// CLEAN UP
IF GETMEMBLOCKEXISTS( RENDERBUFFER ) THEN DELETEMEMBLOCK( RENDERBUFFER )

FUNCTION CLEAR_SCREEN( COLOR AS INTEGER )
	LOCAL POSITION AS INTEGER
	IF GETMEMBLOCKEXISTS( RENDERBUFFER )
		POSITION = SIZEOF_IMAGE_HEADER
		FOR Y = 0 TO DEVICEWIDTH - 1
			FOR X = 0 TO DEVICEHEIGHT - 1
				INC POSITION, SIZEOF_INTEGER
				SETMEMBLOCKINT( RENDERBUFFER, POSITION, COLOR )
			NEXT
		NEXT
	ENDIF
ENDFUNCTION

FUNCTION DRAW_SCREEN( )
	UPDATE(0)
	LOCAL RENDERCACHE AS INTEGER
	IF GETMEMBLOCKEXISTS( RENDERBUFFER )
		RENDERCACHE = CREATEIMAGEFROMMEMBLOCK( RENDERBUFFER )
		SETOBJECTIMAGE( RENDERTARGET, RENDERCACHE, 0 )
		DRAWOBJECT( RENDERTARGET )	
		DELETEIMAGE( RENDERCACHE )	
	ENDIF
	SWAP()
ENDFUNCTION

FUNCTION DRAW_PIXEL( X AS INTEGER, Y AS INTEGER, COLOR AS INTEGER )
	LOCAL POSITION AS INTEGER
	IF GETMEMBLOCKEXISTS( RENDERBUFFER )
		POSITION = ( Y * DEVICEPITCH ) + ( X * SIZEOF_INTEGER ) + SIZEOF_IMAGE_HEADER
		SETMEMBLOCKINT( RENDERBUFFER, POSITION, COLOR )
	ENDIF
ENDFUNCTION

+ Code Snippet

#CONSTANT TRUE					0xFF
#CONSTANT FALSE					0x00

#CONSTANT SIZEOF_IMAGE_HEADER 	12
#CONSTANT SIZEOF_INTEGER			4

#CONSTANT DEVICEWIDTH			640
#CONSTANT DEVICEHEIGHT			480
#CONSTANT DEVICEDEPTH			32
#CONSTANT DEVICEPITCH			(640 * 4)

SETWINDOWSIZE( DEVICEWIDTH, DEVICEHEIGHT, FALSE )
SETSYNCRATE( 0, TRUE )

GLOBAL RENDERBUFFER, RENDERTARGET AS INTEGER
RENDERBUFFER = CREATEMEMBLOCK( SIZEOF_IMAGE_HEADER + (DEVICEWIDTH * DEVICEHEIGHT * SIZEOF_INTEGER) )
			   SETMEMBLOCKINT( RENDERBUFFER, 0, DEVICEWIDTH )
			   SETMEMBLOCKINT( RENDERBUFFER, 4, DEVICEHEIGHT )
			   SETMEMBLOCKINT( RENDERBUFFER, 8, DEVICEDEPTH )
RENDERTARGET = CREATEOBJECTQUAD()

GLOBAL XOLD, YOLD, X, Y AS INTEGER

XOLD = 1
YOLD = 300

REPEAT
	IF X > DEVICEWIDTH
		CLEAR_SCREEN( 0xFF000000 )
		X = 0
	ENDIF
	IF Y > DEVICEHEIGHT
		Y = 0
	ENDIF
	DRAW_PIXEL( X, 50 + 20 * SIN( X * 2 ), MAKECOLOR( 255, 255, 255 ) )
	DRAW_PIXEL( 50 + 20 * SIN(Y * 2), Y, MAKECOLOR( 128, 128, 128 ) )
	INC X
	INC Y
	
	DRAW_SCREEN()
UNTIL GETRAWKEYPRESSED(27)

// CLEAN UP
IF GETMEMBLOCKEXISTS( RENDERBUFFER ) THEN DELETEMEMBLOCK( RENDERBUFFER )

FUNCTION CLEAR_SCREEN( COLOR AS INTEGER )
	LOCAL POSITION AS INTEGER
	IF GETMEMBLOCKEXISTS( RENDERBUFFER )
		POSITION = SIZEOF_IMAGE_HEADER
		FOR Y = 0 TO DEVICEWIDTH - 1
			FOR X = 0 TO DEVICEHEIGHT - 1
				INC POSITION, SIZEOF_INTEGER
				SETMEMBLOCKINT( RENDERBUFFER, POSITION, COLOR )
			NEXT
		NEXT
	ENDIF
ENDFUNCTION

FUNCTION DRAW_SCREEN( )
	UPDATE(0)
	LOCAL RENDERCACHE AS INTEGER
	IF GETMEMBLOCKEXISTS( RENDERBUFFER )
		RENDERCACHE = CREATEIMAGEFROMMEMBLOCK( RENDERBUFFER )
		SETOBJECTIMAGE( RENDERTARGET, RENDERCACHE, 0 )
		DRAWOBJECT( RENDERTARGET )	
		DELETEIMAGE( RENDERCACHE )	
	ENDIF
	SWAP()
ENDFUNCTION

FUNCTION DRAW_PIXEL( X AS INTEGER, Y AS INTEGER, COLOR AS INTEGER )
	LOCAL POSITION AS INTEGER
	IF GETMEMBLOCKEXISTS( RENDERBUFFER )
		POSITION = ( Y * DEVICEPITCH ) + ( X * SIZEOF_INTEGER ) + SIZEOF_IMAGE_HEADER
		SETMEMBLOCKINT( RENDERBUFFER, POSITION, COLOR )
	ENDIF
ENDFUNCTION

This would be considerably easier if AppGameKit Studio didn't deprecate EnableClearColor( ) function, which let's you disable "Clear Screen" but then I have a sneaking suspicion that their Vulkan implementation doesn't utilise the ImageBuffer to switch between RenderBuffer and VkImage.
While the Memblock Peformance is frankly abysmal it's good enough for what we're doing here.

That is to showcase the Animation of Movement.
Now remember, if you want to create a Circle then you'd use COS instead of SIN on one of the Axis... it's common practice to use COS(X) and SIN(Y) but really it actually doesn't matter which way around you do it.

If you ever watch the Movement Patterns in the old Games, you'll see they're creatively using simple formula like this (usually pre-calculated in a Look-Up Table... i.e. an Array) that gives their Enemies all that sweeping Movement; and because with CosSine approach you get more points in smaller arcs, this actually provides the illusion of an enemy slowing down and speeding up.

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fubarpk

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Playing: AGK is my friend

Posted: 14th Mar 2020 07:34 Edited at: 14th Mar 2020 07:36

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pathpoints is one way and I personally think the formula way is the best
but I started work with the path point method here with an editor https://forum.thegamecreators.com/thread/221096
edit Allows you to draw any path you want the enemy to take

fubarpk on Itch...………...https://fubarpk.itch.io/
fubarpk on googleplay..https://play.google.com/store/apps/developer?id=fubarpk

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GreekToMe

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Posted: 16th Mar 2020 20:27

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Excellent responses from all of you!!!
Much appreciated!
Cheers!

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blink0k

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Posted: 16th Mar 2020 20:36

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Sorry. Forgot to attach the project to my post

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GreekToMe

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Posted: 16th Mar 2020 20:58

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A welcome add on

. Thanks!
Cheers!

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AppGameKit Studio Chat / Moving Sprites on a Curve/s has me totally upside down

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