scanning for pixel colors in fullscreen window

[ChebbyShabby]

basically i want to scan the whole fullscreen window pixel-by-pixel until a certain colour is reached (red, in this case).

i have the following code:

Code: Select all

If OpenScreen(800,600,32,"") 
  Repeat
    FlipBuffers() 
    ClearScreen(0,0,0)
    
    StartDrawing(ScreenOutput())
      Box(400, 300, 100, 100, RGB(255, 0, 0))
    StopDrawing()
    
    For y = 0 To 600
      For x = 0 To 800: xx+1: If xx=800: xx=0: yy+1: EndIf: Next
      If yy=600: yy=0: EndIf    
    Next
    
    C = GetPixel_(GetForegroundWindow_(), xx, yy)
      
    StartDrawing(ScreenOutput())
      DrawText(Str(C))
    StopDrawing()
    
    ExamineKeyboard() 
  Until KeyboardPushed(#PB_KEY_ESCAPE) 
  
EndIf

however, GetPixel_() keeps returning -1, why is this? and how can i fix it?

[Dare]

Hi ChebbyShabby,

I dont know if GetPixel_(GetForegroundWindow_( works with screens, but someone smarter than I can confirm that. You could try with Point( to see what happens.

It looks like you do the loops for no reason other than to increment xx,yy until you reset them to 0 and then check the pixel (at 0,0) outside of the loop. That may not be what you want.

Also would going from 0 to 800 and 0 to 600 not do 801 and 601 hits respectively?



PS: Didn't run it, too lazy to load 3.94, so if I am talking out the wrong oriface just ignore this.

[netmaestro]

GetPixel_() works with the hardware device context of the given window. The handle gets you halfway there, but you need the hDC to provide the function with all it needs:

Code: Select all

color=GetPixel_(GetDC_(GetForegroundWindow_()), 100,100)

For a fullscreen app, you get the dc another way:

Code: Select all

color=GetPixel_(GetDC_(ScreenID()),100,100)

and for both environments you can also do the tried and true:

Code: Select all

hDC = StartDrawing(..... StopDrawing()

[ChebbyShabby]

thanks both of you... it helpted
but now i'm having trouble scanning for pixels on the screen

how would i go about a fast way of scanning every pixel on screen? any ideas?

[Kale]

thanks both of you... it helpted
but now i'm having trouble scanning for pixels on the screen

how would i go about a fast way of scanning every pixel on screen? any ideas?

Use the direct video memory access commands. I cant give example yet im at work.

[ChebbyShabby]

thanks kale... but i'm still confused

[K.puts]

Hi, is it a Color-Bot you try to prog ?

[ChebbyShabby]

yeah i'm making a bot. sorry about the late reply

[White Eagle]

Hi, is it a Color-Bot you try to prog ?

Could one of you youngsters please explain to the old man what a "Color-Bot" is?

[K.puts]

Oh sorry, wasn't here for a long, long time. too long.

A color bot is a program for games, p.e. 3d shooters, that detects the color of textures(pixels) and aims on it automaticly, so u can hit ur targets.

u can use the color of of an enemy face or something like that, some detail on an enemy uniform...

i have tested a prog with "enemy territory" and "warrock", the problem is the lightning in 3d games, so pixels don't have the same color all the time, it's a matter of ur position and range.

so the color bot is absolutely ineffective.
but, was a nice try

for anyone else who wants to code such a bot, don't use _getpixel(),
its not fast enough, you can only scan ~50-100² pixels per second with a 1,8 ghz processor.
you have to use direct_x or opengl functions for that, but its realy hard stuff to extraxt the r,g,b information, i gave up on this .

[Fred]

There is a DrawingBuffer() command to have raw access to the pixel buffer. Here is an old source about direct screen access (courtesy of Va!n) : http://www.purebasic.com/Plasma_DSA.pb

[Heathen]

Oh sorry, wasn't here for a long, long time. too long.

A color bot is a program for games, p.e. 3d shooters, that detects the color of textures(pixels) and aims on it automaticly, so u can hit ur targets.

u can use the color of of an enemy face or something like that, some detail on an enemy uniform...

i have tested a prog with "enemy territory" and "warrock", the problem is the lightning in 3d games, so pixels don't have the same color all the time, it's a matter of ur position and range.

so the color bot is absolutely ineffective.
but, was a nice try

for anyone else who wants to code such a bot, don't use _getpixel(),
its not fast enough, you can only scan ~50-100² pixels per second with a 1,8 ghz processor.
you have to use direct_x or opengl functions for that, but its realy hard stuff to extraxt the r,g,b information, i gave up on this .

I hope you get banned from both games People like you make me sick, you can't just enjoy a game without ruining it for others can you? I hope you will be one of the people crying on the warrock forum about getting a HW ban

[Derek]

I hope you get banned from both games People like you make me sick, you can't just enjoy a game without ruining it for others can you? I hope you will be one of the people crying on the warrock forum about getting a HW ban

A bit harsh.
But, yeah, what is the point of playing if you don't actually play, why ruin it for others.

[Heathen]

I hope you get banned from both games People like you make me sick, you can't just enjoy a game without ruining it for others can you? I hope you will be one of the people crying on the warrock forum about getting a HW ban

A bit harsh.
But, yeah, what is the point of playing if you don't actually play, why ruin it for others.

It may sound harsh but it's true. There's nothing worse than someone who get's joy out of taking other's fun away. I personally play warrock, and not long ago the game was flooded with kids like this guy who go game to game just destorying it for everyone. Thank god they reactivated punkbuster and the amount of hackers was reduced. I just hope this guy get's caught.

[Kaeru Gaman]

yeah. cheating in games is a form of impotence...