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Index > Windows > plotting pixels to the screen

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tthsqe



Joined: 20 May 2009
Posts: 730
tthsqe
I'm trying to program a plotter that can animate plots in real time. I've looked at the Julia/Mandelbrot examples which are similar to what I want to do, but have not been able to figure out how to do the following:

1: set screen to 1024 by 768 mode
2: plot a given color at a given pixel coordinate
3: clear the whole screen (to black)
4: plot another point
5: exit upon key press

Would anyone who knows how to do this mind showing me how to code the above into a win32 program? Also, are 2 and 4 as simple as writting the color to a memory location?
Post 25 Jul 2009, 22:48
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bitshifter



Joined: 04 Dec 2007
Posts: 764
Location: Massachusetts, USA
bitshifter
There are 3 popular ways to render in windows.
(You cant write directly to video memory)

1) GDI
2) DirectX
3) OpenGL

What is this application for, a game?
I have many demos, maybe one for you.
Post 26 Jul 2009, 04:44
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tthsqe



Joined: 20 May 2009
Posts: 730
tthsqe
I would like to make a program that animates plots in real-time. Each plot is generated not by calculating a color for each pixel but by a random walk-like process on the screen. Thus, it is almost necessary that the screen be cleared between plots. Each step in the walk requires 40-50 cycles to generate the next screen coordinate, and I would like to do 10^5 - 10^6 or so iterations. If I did the math right, this works out to a max of 46fps on a 2.3GHz cpu for a million iterations. I can't afford a performance hit for plotting each point, so I though writing directly to the screen buffer in memory would be a solution. I have seen something like this in the mandelbrot and juilia set programs involving [ddsd.lpSurface], but have not been able to extract the essential parts of these codes. Is [ddsd.lpSurface] not a pointer to the screen buffer? Any help would be appreciated. I am not too familiar with direct draw code.
Post 26 Jul 2009, 07:14
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bitshifter



Joined: 04 Dec 2007
Posts: 764
Location: Massachusetts, USA
bitshifter
The DX surface is a buffer which gets transfered to screen.
If you are using WinXP or less you can make .com files
which can access video memory for VGA hardware.
That would be the fastest way to plot pixels.
Also i have made a simple OpenGL app which paints pixel.
The relevant code is commented like ;xxxxxxxxxxxxxxxx
If this turns out too slow for you i can help with the VGA coding.
You sure are lucky i have such a passion for graphics coding Very Happy


Description: OpenGL set pixel demo.
Download
Filename: pixel.zip
Filesize: 20.44 KB
Downloaded: 124 Time(s)


_________________
Coding a 3D game engine with fasm is like trying to eat an elephant,
you just have to keep focused and take it one 'byte' at a time.


Last edited by bitshifter on 21 Sep 2009, 12:51; edited 1 time in total
Post 26 Jul 2009, 16:32
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tthsqe



Joined: 20 May 2009
Posts: 730
tthsqe
thanks. I'll write back as soon as I try it out
Post 26 Jul 2009, 18:23
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tthsqe



Joined: 20 May 2009
Posts: 730
tthsqe
Everything seems to be working up to the 1365th point. When glVertex2i is called for the 1365th time in render, something abnormal happens and all of the xmmx registers are cleared upon return. Are you able to reproduce this? Is there a limit to the number of points one can plot in one frame?
Post 27 Jul 2009, 04:33
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bitshifter



Joined: 04 Dec 2007
Posts: 764
Location: Massachusetts, USA
bitshifter
I see no reason why you cant fill the entire resolution.
Post 31 Jul 2009, 20:26
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Kuemmel



Joined: 30 Jan 2006
Posts: 200
Location: Stuttgart, Germany
Kuemmel
Hi tthsqe,

regarding your request about plotting something on the screen and waiting for key pressed, I stripped down my Mandelbrot bench (kind of fast rude strip down, some may be unusefull code, especially for threading left over).

You'll find it attached, it just displays now my palette data. So you should find the plot routine easily now. Everything should be there, like screen address, etc etc. Just read also up about DirectDraw, you need 'ddsd.lpSurface' for the address and also 'ddsd.lPitch'...to have the right offsets in case there.

You asked also about clearing the screen...so I don't do that in my code...but it would be just a memory fill to the screen or may be or for sure there might be some faster DirectDraw routine for that (sorry not a DirectDraw expert).


Description:
Download
Filename: KMB_plot.zip
Filesize: 5.17 KB
Downloaded: 64 Time(s)

Post 03 Aug 2009, 19:59
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windwakr



Joined: 30 Jun 2004
Posts: 827
Location: Michigan, USA
windwakr
Kuemmel, have you tested that code? On my computer it went to fullscreen, drew the palette, and then COMPLETELY LOCKED UP MY SYSTEM. I had to hard boot my computer.
Post 03 Aug 2009, 20:18
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vid
Verbosity in development


Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia
vid
IMO the easiest to use is SDL.
Post 03 Aug 2009, 21:03
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windwakr



Joined: 30 Jun 2004
Posts: 827
Location: Michigan, USA
windwakr
Someone should code up an example of SDL in assembly, I can't find anything about using it in assembly. It would require a lot of include converting...Ok, nvm...
Post 03 Aug 2009, 21:07
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Kuemmel



Joined: 30 Jan 2006
Posts: 200
Location: Stuttgart, Germany
Kuemmel
windwakr wrote:
Kuemmel, have you tested that code? On my computer it went to fullscreen, drew the palette, and then COMPLETELY LOCKED UP MY SYSTEM. I had to hard boot my computer.

Hm, works well here on Vista 64 (but is 32bit code)...use ESC to exit after drawing...as I said, was quite a fast hack, might have some problems...the SDL stuff sounds quite nice...anybody setting it up for FASM !?
Post 03 Aug 2009, 21:46
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windwakr



Joined: 30 Jun 2004
Posts: 827
Location: Michigan, USA
windwakr
I have 32 bit win xp sp3, It completely locks it up. ESC does nothing.

SDL in FASM would be quite an undertaking, but that would be awesome if someone managed it. Anyone here wanna do it? Too bad its not as simple as just importing the dll....
Post 03 Aug 2009, 21:54
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c rex



Joined: 10 Sep 2009
Posts: 1
c rex
I used to code in visual basic, and someone showed me StretchDiBits which typically beats opengl and directx because they must convert video memory to normal ram, you do math, and memory is shot back to ram

Code:
Type RGBQUAD
 Blue  As Byte
 Green As Byte
 Red   As Byte
 Alpha As Byte
End Type

Type BITMAPINFOHEADER
    biSize          As Long 'vb 32 bits
    biWidth         As Long
    biHeight        As Long
    biPlanes        As Integer 'vb 16 bits
    biBitCount      As Integer
    biCompression   As Long
    biSizeImage     As Long
    biXPelsPerMeter As Long
    biYPelsPerMeter As Long
    biClrUsed       As Long
    biClrImportant  As Long
End Type

Type BITMAPINFO
    bmiHeader As BITMAPINFOHEADER
    bmiColors As RGBQUAD
End Type

Declare Function StretchDIBits Lib "gdi32" _
        (ByVal hDC As Long, _
         ByVal X As Long, _
         ByVal Y As Long, _
         ByVal dx As Long, _
         ByVal dy As Long, _
         ByVal SrcX As Long, _
         ByVal SrcY As Long, _
         ByVal wSrcWidth As Long, _
         ByVal wSrcHeight As Long, _
         lpBits As Any, _
         lpBitsInfo As BITMAPINFOHEADER, _
         ByVal wUsage As Long, _
         ByVal dwRop As Long) As Long

Public Const BI_RGB         As Long = 0
Public Const DIB_RGB_COLORS As Long = 0

'Function call

StretchDIBits DC, _
      X, Y, Wid, Hgt, _
      0, 0, BIH.biWidth, BIH.biHeight, _
      Array32bpp(0, 0), BIH, DIB_RGB_COLORS, vbSrcCopy
    

I think vbSrcCopy = 0
Post 11 Sep 2009, 20:59
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pabloreda



Joined: 24 Jan 2007
Posts: 104
Location: Argentina
pabloreda
Hi, perhaps this help

I'm finish the core for compile and I use StretchDiBits, I don't finish the fullscreen mode.

this example fill the buffer and copy to video.


Description: core for :r4 language
Download
Filename: r4fasm.rar
Filesize: 3.73 KB
Downloaded: 59 Time(s)

Post 15 Oct 2009, 15:20
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Rahsennor



Joined: 07 Jul 2007
Posts: 61
Rahsennor
Google TinyPTC and its successor pixeltoaster. They use C, but they do exactly (and only) what you want and shouldn't take much to port to fasm.
Post 09 Nov 2009, 02:42
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