Image Processor with LUA

Community Forums/Showcase/Image Processor with LUA

degac

(Posted 2009) [#1]

Hi, this morning I've started (from scratch) my first application with LUA support (I dont' know quite anything about its syntax...but give me time...)

The first application (is just a test to understand the basis) is a simple Image Processor. Basically the Bmx program loads an image and the LUA script can interact with it: nothing special I know...

I've implemented some RGB/YUV function that are not *so* perfect (or didnt' work at all...) but remember it is only a starting point

PS: I've used a LUA-type structure, I dont' like very much the LuaL_procedure implemented in MaxLUA. I prefer something more understandable
this is more clear - for now and my knowledge of Lua

Lua.SetVar("width",320)

than

lua_pushstring(lua_State,_name)
lua_pushnumber(lua_State, value)
lua_settable(lua_State , LUA_GLOBALSINDEX)

Graphics 640,480
Global current_pixmap:TPixmap=LoadPixmap("contacts.png")

Type LuaScript
	Global lua_state:Byte Ptr
	
	Method New() 
		lua_State = luaL_newstate()
		luaL_openlibs(lua_State)
	EndMethod
	
	Method Run(source:String) 
		'execture a script
		'reports the error in negative case
		If luaL_dostring(Lua_state,source)
			Print "Error: "+lua_tostring(Lua_state,-1)
		EndIf
	EndMethod
	
	Method SetVar:Int(_name$,value:Int)
	'set a variable for LUA
		lua_pushstring(lua_State,_name)
		lua_pushnumber(lua_State, value)
		lua_settable(lua_State , LUA_GLOBALSINDEX) 
	End Method
	
	Method RegisterFunction(_luaName$,fun(p:Byte Ptr))
		lua_register(lua_State,_luaName,fun)	
	End Method
	
	Method Stop()
		lua_close(Lua_state)
	End Method
	
	Method GetInt:Int(_index:Int=1)
		Return luaL_checkinteger(lua_state,_index)	
	End Method

	Method GetString:String(_index:Int)
		Return lua_tostring(lua_state,_index)
	End Method

End Type



Global LUA:LuaScript=New LuaScript

Global pix_w:Int=PixmapWidth(current_pixmap)
Global pix_h:Int=PixmapHeight(current_pixmap)


lua.SetVar("width",pix_w)
lua.SetVar("height",pix_h)
lua.SetVar("RGB",0)
lua.SetVar("x",0)
lua.SetVar("y",0)
lua.setVar("RED",0)
lua.setVar("GREEN",0)
lua.setVar("BLUE",0)
lua.setVar("ALPHA",0)




lua.RegisterFunction("echo",BMX_ECHO)
lua.Run("echo('Size is:'..width..' x '..height)")
lua.run("echo('RGB:'..RGB)")

lua.RegisterFunction("get_rgb",LUA_GET_RGB)
lua.RegisterFunction("set_rgb",LUA_SET_RGB)
lua.RegisterFunction("set_yuv",LUA_SET_YUV)'not perfect
lua.RegisterFunction("get_yuv",LUA_GET_YUV)'not perfect

'--- interactive function
lua.RegisterFunction("update",LUA_UPDATE)
lua.RegisterFunction("UserAction",LUA_USERACTION)
lua.RegisterFunction("LoadImage",LUA_LOADIMAGE)


lua.Run(LoadText("Lua_script1.lua"))

DrawPixmap current_pixmap,0,0
Flip
Rem
	For Local X:Int=0 Until PIX_W
	For Local Y:Int=0 Until PIX_H
	
	Get_Yuv:Int(current_pixmap,x,y)
	
	Next
	Next
End Rem

WaitKey
End 

Function BMX_ECHO:Int(ls:Byte Ptr)
	Local msg:String = lua_tostring(ls, 1)
	If String(msg)
		 Print msg
	Else
		Print lua_tonumber(ls, 1)
	EndIf

	Return 0
End Function

Function LUA_GET_RGB:Int(ls:Byte Ptr)
	Local x:Int=lua.getInt(1)
	Local Y:Int=lua.getInt(2)
	Get_Rgb(current_pixmap,x,y)
End Function
Function LUA_GET_YUV:Int(ls:Byte Ptr)
	Local x:Int=lua.getInt(1)
	Local Y:Int=lua.getInt(2)
	Get_Yuv(current_pixmap,x,y)

End Function




Function LUA_UPDATE(ls:Byte Ptr)
'	Print "Update draw..."
	If current_pixmap=Null Return
	DrawPixmap current_pixmap,0,0
Flip
	
End Function


Function LUA_USERACTION(ls:Byte Ptr)
	Notify lua.getString(1)
End Function

Function LUA_LOADIMAGE(ls:Byte Ptr)
	Local file:String=RequestFile("Load an image","Images:bmp,png,tga",False)
	If file<>""
		current_pixmap:TPixmap=LoadPixmap(file)	
		
		pix_w=PixmapWidth(current_pixmap)
		pix_h=PixmapHeight(current_pixmap)
		lua.SetVar("width",pix_w)
		lua.SetVar("height",pix_h)
				
	End If
	
End Function

Function LUA_SET_RGB:Int(ls:Byte Ptr)
	Local x:Int=lua.getInt(1)
	Local Y:Int=lua.getInt(2)
	Local re:Int,bl:Int,gr:Int
	
	re=lua.getInt(3)
	gr=Lua.getInt(4)
	bl=Lua.getInt(5)

	Set_Rgb(current_pixmap,x,y,re,gr,bl)
End Function

Function LUA_SET_YUV:Int(LS:Byte Ptr)
	Local x:Int=lua.getInt(1)
	Local Y:Int=lua.getInt(2)
	Local Y1:Int,U1:Int,V1:Int
	
	Y1=lua.getInt(3)
	U1=Lua.getInt(4)
	V1=Lua.getInt(5)

	Set_Yuv(current_pixmap,x,y,y1,u1,v1)
End Function

Function Get_Yuv:Int(_pix:TPixmap,x:Int,y:Int)
	If _pix=Null Return
	'If x<0 Or y<0 Or x>PixmapWidth(_pix) Or y>PixmapHeight(_pix) Return -1
	Local asrgb:Int=ReadPixel(_pix,x,y)
	
	rgb(asrgb,re,gr,bl)
	Lua.SetVar("RED",re)
	Lua.SetVar("GREEN",gr)
	Lua.SetVar("BLUE",bl)
	
	Local y1:Float ,u1:Float ,v1:Float 
	
	Rgb2Yuv(Re,gr,bl,Y1,u1,v1)

	lua.setVar("Y1",Y1)
	lua.setVar("U1",U1)
	lua.setVar("V1",V1)
		
End Function

Function SET_YUV:Int(_pix:TPixmap,x:Int,y:Int,y1:Int,u1:Int,v1:Int)
	If _pix=Null Print "No pix";Return
	Local r:Int,g:Int,b:Int
	
	Yuv2Rgb(y1,u1,v1,r,g,b)
	
	Local col:Int=IntColor(r,g,b)
	WritePixel _pix,x,y,col
	
End Function


Function Get_rgb:Int(_pix:TPixmap,x:Int,y:Int)
	If _pix=Null Return
	'If x<0 Or y<0 Or x>PixmapWidth(_pix) Or y>PixmapHeight(_pix) Return -1
	Local ssrgb:Int=ReadPixel(_pix,x,y)
	
	Local re:Int,gr:Int,bl:Int
	
	rgb(ssrgb,re,gr,bl)
	Lua.SetVar("RED",re)
	Lua.SetVar("GREEN",gr)
	Lua.SetVar("BLUE",bl)
		
	Return ssrgb
	
End Function


Function rgb(pixelValue%,red:Int Var,green:Int Var,blue:Int Var)
	Local r%, g%, b%
	pixelValue = ($00ffffff & pixelvalue) 'gets rid of the alpha bits making the number make sense
	red = pixelvalue/$10000
	pixelValue = ($00ffff & pixelvalue) 'removes the r value
	green = pixelvalue/$100
	pixelValue = ($00ff & pixelvalue) 'removes the g value leaving only b
	blue = pixelvalue
	Return
EndFunction

Function set_yiq2rgb:Int(y#,i#,q#)

End Function


Function Set_rgb:Int(_pix:TPixmap,x:Int,y:Int,r:Int,g:Int,b:Int)
	
	If _pix=Null Print "No pix";Return
	
	Local col:Int=IntColor(r,g,b)
	WritePixel _pix,x,y,col
	
	
End Function

Function IntColor(R:Int,G:Int,B:Int,A:Int=0)
     Return A Shl 24 | R Shl 16 | G Shl 8 | B Shl 0
End Function

Rem
	Convert RGB 2 YUV
End Rem
Function Rgb2Yuv(R:Int,B:Int,G:Int,Y:Float Var,U:Float Var,V:Float Var)
	Y = 0.299*Float(R) + 0.587*Float(G) + 0.114*Float(B)
	U= Float(B-Y)*0.565
	V= Float(R-Y)*0.713
	'Print r+" "+g+" "+b
	'Print r+" "+g+" "+b+" --> "+Y+" "+u+" "+v
	
	Return
End Function
Rem
	convert Yuv 2 RGB
End Rem
Function Yuv2Rgb:Int(Y:Int,U:Int,V:Int,R:Int Var,G:Int Var,B:Int Var)
	R = Y + 1.403*V
	G = Y - 0.344*U - 0.714*V
	B = Y + 1.770*U
	Return
End Function

echo('Starting...')
-- LoadImage()
-- this writes a RED rect from 10,10 to 20,20 on the image
for y = 10, 20 do
  for x = 10, 20 do
	set_rgb(x,y,255,x,y)
	--update()
  end
end 
update()

UserAction('Press any key to continue')
-- color components are RED GREEN BLUE

for y = 0, height - 1 do
  for x = 0, width -1 do
  	get_rgb(x, y)
    RED = RED * (x / width)
    set_rgb(x, y, RED,GREEN,BLUE)
  end
end
update()

UserAction("Yuv example")
-- YUV components are Y1 U1 V1
for y = 0, height - 1 do
  for x = 0, width -1 do
    get_yuv(x, y)
    U1 = U1 * (x / width)
	--echo("Y1 U1 V1 "..Y1.." "..U1.." "..V1)
    set_yuv(x, y, Y1,U1,V1)
  end
end
echo('finished...')

PS: there are very few tutorials on how interface BlitzMax to LUA...and what I found is related to something very OLD (more than 3 years with modules gone).
Comments and suggestions are welcomed.