Image blending with memblocks - GameCreators Forum

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Scraggle

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Posted: 5th Feb 2015 21:13 Edited at: 6th Feb 2015 16:15

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Hi,

[Edit]I've edited the AppGameKit code to show the now working version should anyone wish to use it

[/Edit]

Back in 2007 I wrote a function that would blend two images together based on a third alpha mask image and posted here on the code snippets board. I'm trying to convert it to AppGameKit which I thought would be pretty straight forward but it isn't working.
Is there a BUG with the memblock image commands or am I doing something wacky that I can't see?

This is the original code from the link above:

`------------------------------
`Project : Memblock Image Blend
`------------------------------
`Author	: Scraggle
`------------------------------
`Started : 9th September 2007
`------------------------------

`------------------------------------------------------------------------------
`Note:		This project will take two images of any size (equal or not)
`				and blend them together according to the values of a third
`				greyscale alpha map image

`				It has been written as a function so that is can easily be 
`				included in any project.  The parameters for the function are 
`				listed below

`IMPORTANT: In order to use the code as it is, you will need to download and 
`				install IanM\'s Matrix1 Utils plug-in.
`				You can still run the code with out the plugin but you will need 
`				to change the FIND FREE MEMBLOCK() & FIND FREE BITMAP() commands.
`------------------------------------------------------------------------------

`------------------------------------------------------------------------------
`PARAMETERS:
`iUpper : 	The image that will show through in the white areas of the alpha map
`iLower : 	The image that will show through in the black areas of the alpha map
`iAlpha : 	The greyscale image used to blend iUpper & iLower
`iResult: 	The image number of the resultant blended image
`Width  : 	The width you want the resultant image to be
`Height : 	The height you want the resultant image to be

`Note   : 	The images do not need to be the same size nor do any of them need to 
`         	be the size of the resultant image.  
`         	They will all be scaled automatically.
`------------------------------------------------------------------------------

function blend_Images( iUpper, iLower, iAlpha, iResult, Width, Height)
	
	Local Percent		as float
	Local UpperBlue	as byte
	Local UpperGreen	as byte
	Local UpperRed		as byte
	Local LowerBlue	as byte
	Local LowerGreen	as byte
	Local LowerRed		as byte
	Local ResultBlue	as byte
	Local ResultGreen	as byte
	Local ResultRed	as byte
	Local mUpper 		as integer
	Local mLower 		as integer
	Local mAlpha		as integer
	Local mResult 		as integer

if image width(iUpper) <> width or image height(iUpper) <> height then iUpper = ResizeImage( iUpper, Width, Height )
	if image width(iLower) <> width or image height(iLower) <> height then iLower = ResizeImage( iLower, Width, Height )
	if image width(iAlpha) <> width or image height(iAlpha) <> height then iAlpha = ResizeImage( iAlpha, Width, Height )
			
	mUpper  = find free memblock(  1, 10 )
	mLower  = find free memblock( 11, 10 )
	mAlpha  = find free memblock( 21, 10 )
	mResult = find free memblock( 31, 10 )
	
	make memblock from image mUpper,  iUpper
	make memblock from image mLower,  iLower
	make memblock from image mAlpha,  iAlpha
	make memblock from image mResult, iUpper
	
	mbSize = get memblock size( mUpper )
	for Pos = 12 to mbSize - 12 step 4

Percent     = ( memblock byte( mAlpha, Pos ) / 255.0 )
		
		UpperBlue   = memblock byte( mUpper, Pos + 0 )
		UpperGreen  = memblock byte( mUpper, Pos + 1 )
		UpperRed    = memblock byte( mUpper, Pos + 2 )

LowerBlue   = memblock byte( mLower, Pos + 0 )
		LowerGreen  = memblock byte( mLower, Pos + 1 )
		LowerRed    = memblock byte( mLower, Pos + 2 )

ResultBlue  = UpperBlue  * ( 1- Percent ) + LowerBlue  * Percent
		ResultGreen = UpperGreen * ( 1- Percent ) + LowerGreen * Percent
		ResultRed   = UpperRed   * ( 1- Percent ) + LowerRed   * Percent
						
		write memblock byte mResult, Pos + 0, ResultBlue
		write memblock byte mResult, Pos + 1, ResultGreen
		write memblock byte mResult, Pos + 2, ResultRed
		write memblock byte mResult, Pos + 3, 255
		
	next Pos
	
	make image from memblock iResult, mResult
	
	delete memblock mUpper
	delete memblock mLower
	delete memblock mAlpha
	delete memblock mResult
			
endfunction

function ResizeImage( Image, Width, Height )

bResize = find free bitmap()	
	Create Bitmap bResize, width, height

sprite 1, 5000, 5000, Image
	size sprite 1, width, height
	paste sprite 1, 0,0
	get image Image, 0, 0, width, height, 1
	
	delete bitmap bResize
	
endfunction Image

+ Code Snippet

`------------------------------
`Project : Memblock Image Blend
`------------------------------
`Author	: Scraggle
`------------------------------
`Started : 9th September 2007
`------------------------------

`------------------------------------------------------------------------------
`Note:		This project will take two images of any size (equal or not)
`				and blend them together according to the values of a third
`				greyscale alpha map image 

`				It has been written as a function so that is can easily be 
`				included in any project.  The parameters for the function are 
`				listed below

`IMPORTANT: In order to use the code as it is, you will need to download and 
`				install IanM\'s Matrix1 Utils plug-in.
`				You can still run the code with out the plugin but you will need 
`				to change the FIND FREE MEMBLOCK() & FIND FREE BITMAP() commands.
`------------------------------------------------------------------------------


`------------------------------------------------------------------------------
`PARAMETERS:
`iUpper : 	The image that will show through in the white areas of the alpha map
`iLower : 	The image that will show through in the black areas of the alpha map
`iAlpha : 	The greyscale image used to blend iUpper & iLower
`iResult: 	The image number of the resultant blended image
`Width  : 	The width you want the resultant image to be
`Height : 	The height you want the resultant image to be

`Note   : 	The images do not need to be the same size nor do any of them need to 
`         	be the size of the resultant image.  
`         	They will all be scaled automatically.
`------------------------------------------------------------------------------

function blend_Images( iUpper, iLower, iAlpha, iResult, Width, Height)
	
	Local Percent		as float
	Local UpperBlue	as byte
	Local UpperGreen	as byte
	Local UpperRed		as byte
	Local LowerBlue	as byte
	Local LowerGreen	as byte
	Local LowerRed		as byte
	Local ResultBlue	as byte
	Local ResultGreen	as byte
	Local ResultRed	as byte
	Local mUpper 		as integer
	Local mLower 		as integer
	Local mAlpha		as integer
	Local mResult 		as integer

	if image width(iUpper) <> width or image height(iUpper) <> height then iUpper = ResizeImage( iUpper, Width, Height )
	if image width(iLower) <> width or image height(iLower) <> height then iLower = ResizeImage( iLower, Width, Height )
	if image width(iAlpha) <> width or image height(iAlpha) <> height then iAlpha = ResizeImage( iAlpha, Width, Height )
			
	mUpper  = find free memblock(  1, 10 )
	mLower  = find free memblock( 11, 10 )
	mAlpha  = find free memblock( 21, 10 )
	mResult = find free memblock( 31, 10 )
	
	make memblock from image mUpper,  iUpper
	make memblock from image mLower,  iLower
	make memblock from image mAlpha,  iAlpha
	make memblock from image mResult, iUpper
	
	mbSize = get memblock size( mUpper )
	for Pos = 12 to mbSize - 12 step 4

		Percent     = ( memblock byte( mAlpha, Pos ) / 255.0 )
		
		UpperBlue   = memblock byte( mUpper, Pos + 0 )
		UpperGreen  = memblock byte( mUpper, Pos + 1 )
		UpperRed    = memblock byte( mUpper, Pos + 2 )

		LowerBlue   = memblock byte( mLower, Pos + 0 )
		LowerGreen  = memblock byte( mLower, Pos + 1 )
		LowerRed    = memblock byte( mLower, Pos + 2 )

		ResultBlue  = UpperBlue  * ( 1- Percent ) + LowerBlue  * Percent
		ResultGreen = UpperGreen * ( 1- Percent ) + LowerGreen * Percent
		ResultRed   = UpperRed   * ( 1- Percent ) + LowerRed   * Percent
						
		write memblock byte mResult, Pos + 0, ResultBlue
		write memblock byte mResult, Pos + 1, ResultGreen
		write memblock byte mResult, Pos + 2, ResultRed
		write memblock byte mResult, Pos + 3, 255
		
	next Pos
	
	make image from memblock iResult, mResult
	
	delete memblock mUpper
	delete memblock mLower
	delete memblock mAlpha
	delete memblock mResult
			
endfunction
	

function ResizeImage( Image, Width, Height )

	bResize = find free bitmap()	
	Create Bitmap bResize, width, height

	sprite 1, 5000, 5000, Image
	size sprite 1, width, height
	paste sprite 1, 0,0
	get image Image, 0, 0, width, height, 1
	
	delete bitmap bResize
	
endfunction Image

And this is my attempt to convert it to AppGameKit v2:

`------------------------------
`Project : Memblock Image Blend
`------------------------------
`Author	: Scraggle
`------------------------------
`Started : 4th February 2015
`------------------------------

`------------------------------------------------------------------------------
`Note:		This project will take two images of any size (equal or not)
`				and blend them together according to the values of a third
`				greyscale alpha map image

`				It has been written as a function so that is can easily be 
`				included in any project.  The parameters for the function are 
`				listed below

`			 	Converted to AGK from the original DBP code
`------------------------------------------------------------------------------

`------------------------------------------------------------------------------
`PARAMETERS:
`iUpper : 	The image that will show through in the white areas of the alpha map
`iLower : 	The image that will show through in the black areas of the alpha map
`iAlpha : 	The greyscale image used to blend iUpper & iLower
`iResult: 	The image number of the resultant blended image
`Width  : 	The width you want the resultant image to be
`Height : 	The height you want the resultant image to be

`Note   : 	The images do not need to be the same size nor do any of them need to 
`         	be the size of the resultant image.  
`         	They will all be scaled automatically.
`------------------------------------------------------------------------------

function blend_Images( iUpper, iLower, iAlpha, Width, Height)
	
	Local Percent		as float
	Local UpperBlue		as integer
	Local UpperGreen	as integer
	Local UpperRed		as integer
	Local LowerBlue		as integer
	Local LowerGreen	as integer
	Local LowerRed		as integer
	Local ResultBlue	as integer
	Local ResultGreen	as integer
	Local ResultRed		as integer
	Local mUpper 		as integer
	Local mLower 		as integer
	Local mAlpha		as integer
	Local mResult 		as integer
	Local iResult 		as integer

if getimagewidth(iUpper) <> width or getimageheight(iUpper) <> height then iUpper = ResizeImage( iUpper, Width, Height )
	if getimagewidth(iLower) <> width or getimageheight(iLower) <> height then iLower = ResizeImage( iLower, Width, Height )
	if getimagewidth(iAlpha) <> width or getimageheight(iAlpha) <> height then iAlpha = ResizeImage( iAlpha, Width, Height )
			
	mUpper  = 1
	mLower 	= 2
	mAlpha  = 3
	mResult = 4
	
	CreateMemblockFromImage( mUpper,  iUpper )
	CreateMemblockFromImage( mLower,  iLower )
	CreateMemblockFromImage( mAlpha,  iAlpha )
	CreateMemblockFromImage( mResult, iUpper )
	
	mbSize = getmemblocksize( mUpper )
	for Pos = 12 to mbSize step 4

Percent     = ( getmemblockbyte( mAlpha, Pos ) / 255.0 )
		
		UpperBlue   = getMemblockByte( mUpper, Pos + 0 )
		UpperGreen  = getMemblockByte( mUpper, Pos + 1 )
		UpperRed    = getMemblockByte( mUpper, Pos + 2 )

LowerBlue   = getMemblockByte( mLower, Pos + 0 )
		LowerGreen  = getMemblockByte( mLower, Pos + 1 )
		LowerRed    = getMemblockByte( mLower, Pos + 2 )

ResultBlue  = UpperBlue  * ( 1- Percent ) + LowerBlue  * Percent
		ResultGreen = UpperGreen * ( 1- Percent ) + LowerGreen * Percent
		ResultRed   = UpperRed   * ( 1- Percent ) + LowerRed   * Percent
						
		setmemblockbyte( mResult, Pos + 0, ResultBlue )
		setmemblockbyte( mResult, Pos + 1, ResultGreen )
		setmemblockbyte( mResult, Pos + 2, ResultRed )
		setmemblockbyte( mResult, Pos + 3, 255 )
		
	next Pos
	
	iResult = CreateImageFromMemblock( mResult )

deletememblock( mUpper )
	deletememblock( mLower )
	deletememblock( mAlpha )
	deletememblock( mResult )
			
endfunction iResult

function ResizeImage( Image, Width, Height )

s = CreateSprite( image )
	SetSpriteSize( s, Width, Height )
	SetSpritePosition( s, 0, 0 )
	Render()
	i = GetImage( 0, 0, Width, Height )
	
	DeleteSprite( s )
	
endfunction i

+ Code Snippet

`------------------------------
`Project : Memblock Image Blend
`------------------------------
`Author	: Scraggle
`------------------------------
`Started : 4th February 2015
`------------------------------

`------------------------------------------------------------------------------
`Note:		This project will take two images of any size (equal or not)
`				and blend them together according to the values of a third
`				greyscale alpha map image 

`				It has been written as a function so that is can easily be 
`				included in any project.  The parameters for the function are 
`				listed below

`			 	Converted to AGK from the original DBP code
`------------------------------------------------------------------------------


`------------------------------------------------------------------------------
`PARAMETERS:
`iUpper : 	The image that will show through in the white areas of the alpha map
`iLower : 	The image that will show through in the black areas of the alpha map
`iAlpha : 	The greyscale image used to blend iUpper & iLower
`iResult: 	The image number of the resultant blended image
`Width  : 	The width you want the resultant image to be
`Height : 	The height you want the resultant image to be

`Note   : 	The images do not need to be the same size nor do any of them need to 
`         	be the size of the resultant image.  
`         	They will all be scaled automatically.
`------------------------------------------------------------------------------

function blend_Images( iUpper, iLower, iAlpha, Width, Height)
	
	Local Percent		as float
	Local UpperBlue		as integer
	Local UpperGreen	as integer
	Local UpperRed		as integer
	Local LowerBlue		as integer
	Local LowerGreen	as integer
	Local LowerRed		as integer
	Local ResultBlue	as integer
	Local ResultGreen	as integer
	Local ResultRed		as integer
	Local mUpper 		as integer
	Local mLower 		as integer
	Local mAlpha		as integer
	Local mResult 		as integer
	Local iResult 		as integer

	if getimagewidth(iUpper) <> width or getimageheight(iUpper) <> height then iUpper = ResizeImage( iUpper, Width, Height )
	if getimagewidth(iLower) <> width or getimageheight(iLower) <> height then iLower = ResizeImage( iLower, Width, Height )
	if getimagewidth(iAlpha) <> width or getimageheight(iAlpha) <> height then iAlpha = ResizeImage( iAlpha, Width, Height )
			
	mUpper  = 1
	mLower 	= 2
	mAlpha  = 3
	mResult = 4
	
	CreateMemblockFromImage( mUpper,  iUpper )
	CreateMemblockFromImage( mLower,  iLower )
	CreateMemblockFromImage( mAlpha,  iAlpha )
	CreateMemblockFromImage( mResult, iUpper )
	
	mbSize = getmemblocksize( mUpper )
	for Pos = 12 to mbSize step 4

		Percent     = ( getmemblockbyte( mAlpha, Pos ) / 255.0 )
		
		UpperBlue   = getMemblockByte( mUpper, Pos + 0 )
		UpperGreen  = getMemblockByte( mUpper, Pos + 1 )
		UpperRed    = getMemblockByte( mUpper, Pos + 2 )

		LowerBlue   = getMemblockByte( mLower, Pos + 0 )
		LowerGreen  = getMemblockByte( mLower, Pos + 1 )
		LowerRed    = getMemblockByte( mLower, Pos + 2 )

		ResultBlue  = UpperBlue  * ( 1- Percent ) + LowerBlue  * Percent
		ResultGreen = UpperGreen * ( 1- Percent ) + LowerGreen * Percent
		ResultRed   = UpperRed   * ( 1- Percent ) + LowerRed   * Percent
						
		setmemblockbyte( mResult, Pos + 0, ResultBlue )
		setmemblockbyte( mResult, Pos + 1, ResultGreen )
		setmemblockbyte( mResult, Pos + 2, ResultRed )
		setmemblockbyte( mResult, Pos + 3, 255 )
		
	next Pos
	
	iResult = CreateImageFromMemblock( mResult )

	
	deletememblock( mUpper )
	deletememblock( mLower )
	deletememblock( mAlpha )
	deletememblock( mResult )
			
endfunction iResult
	

function ResizeImage( Image, Width, Height )

	s = CreateSprite( image )
	SetSpriteSize( s, Width, Height )
	SetSpritePosition( s, 0, 0 )
	Render()
	i = GetImage( 0, 0, Width, Height )
	
	DeleteSprite( s )
	
endfunction i

If you'd like to test it then I used this test code to call the function:

+ Code Snippet

// Project: Image Functions 
// Created: 2015-02-04

// set window properties
SetWindowTitle( "Image Functions" )
SetWindowSize( 768, 512, 0 )

// set display properties
SetVirtualResolution( 768, 512 )
SetOrientationAllowed( 1, 1, 1, 1 )

#include "Image Functions.agc"

type tImage
	img as integer
	spr as integer
endtype

Grass as tImage
Rock as tImage
Mask as tImage
Result as tImage


Grass.img = LoadImage( "Grass.png" )
Rock.img = LoadImage( "Rock.png" )
Mask.img = LoadImage( "mask.png" )

Result.img = blend_Images( Grass.img, Rock.img, Mask.img, 256, 256 )

Grass.spr = CreateSprite( Grass.img )
Mask.spr = CreateSprite( Mask.img )
Rock.spr = CreateSprite( Rock.img )
Result.spr = CreateSprite( Result.img )

SetSpritePosition( Grass.spr, 0, 0 )
SetSpritePosition( Mask.spr, 256, 0 )
SetSpritePosition( Rock.spr, 512, 0 )
SetSpritePosition( Result.spr, 256, 256 )

do
    Sync()
loop

And I've attached the images I used to this post

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CJB

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Posted: 6th Feb 2015 10:55 Edited at: 6th Feb 2015 11:02

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It doesn't like iResult for some reason. Swapped it for a constant and BOOM!

These are the changes I made to the blend_images function:

+ Code Snippet

	
`	CreateImageFromMemblock( iResult, mResult )
	CreateImageFromMemblock( 100, mResult )
	s = CreateSprite(100)
	SetSpritePosition(s, 500, 0)
	SetSpriteSize(s, 256, 256)

`	do
		print(mbSize)
		print(GetImageWidth(iResult))
		print(GetImageHeight(iResult))
		print(GetSpriteWidth(s))
		print(GetSpriteHeight(s))
		sync()
`	loop
	
	deletememblock( mUpper )
	deletememblock( mLower )
	deletememblock( mAlpha )
	deletememblock( mResult )
			
endfunction 100

I'm guessing it is something to do with iResult being a local variable in the function. No idea why you can't return that value though :s I hope this points you in the right direction!

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Uzmadesign

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BatVink

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Posted: 6th Feb 2015 11:51

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I'm impressed that you picked out iResult as the culprit!
It's because iResult is 0, it never gets set.

This should also fix it, replace:

CreateImageFromMemblock( iResult, mResult )

with

iResult = CreateImageFromMemblock(mResult)

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CJB

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Posted: 6th Feb 2015 14:58

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"I can only show you the door. You're the one that has to walk through it."

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BatVink

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Posted: 6th Feb 2015 15:07

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You have the look of a man who accepts what he sees because he expects to wake up

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Scraggle

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Posted: 6th Feb 2015 16:10 Edited at: 6th Feb 2015 16:11

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Thank you both of you.

I'm not sure why we have slipped into matrix quotes but thanks anyway

So, what have we learned here?
Is there a bug in the createImageFromMemblock command? Or should the help files be amended?

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BatVink

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Posted: 6th Feb 2015 16:21

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The help files are ok, there's 2 ways of writing the command. The way you wrote it requires you to manually set the imageID (iResult). Because it was 0, it failed silently and gave you an empty image.

I think you wanted it to automatically assign a new image number to it, in which case you need the second syntax, as shown in my post above.

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Scraggle

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Posted: 6th Feb 2015 17:45

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I don't think the help files are OK.
It's this part I have an issue with:

Quote: " if the image exists it will be overwritten, if not it will be created."

That obviously didn't happen for me and no error was reported either.

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JimHawkins

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Posted: 6th Feb 2015 17:47

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Isn't zero an invalid ID?

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BatVink

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Posted: 6th Feb 2015 17:53 Edited at: 6th Feb 2015 17:55

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Quote: "if the image exists it will be overwritten.."

If you have a nice image of an alien in image 99 then:

CreateImageFromMemblock( 99, memID )

will replace your alien with your memblock image.

Quote: "...if not it will be created."

If image 99 has never been used then:

CreateImageFromMemblock( 99, memID )

will create the image.

But this will never work:

CreateImageFromMemblock( 0, memID )

because you can't have an image 0. Thisis what your code has tried to do. AppGameKit fails silenty. In other words the damage isn't catastrophic enough to halt your program, so it carries on without erroring. This is an expectation of iOS and Android. You can use GetErrorOccurred() to manually check, or SetErrorMode() to force an error.

Finally...

iResult = CreateImageFromMemblock( memID )

will return an image ID plucked from the pool. These start at 10,000 and increment each time you create an image.

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AppGameKit Classic Chat / Image blending with memblocks

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