For my graphics class, I need to match an OpenGL sample output in a pixel-perfect way.
I figured it would be cool if I could spawn the sample, send it some input, then take a screenshot of the exact OpenGL area, do the same for mine, and then just compare those screenshots. I also figured something like AutoIT would be the easiest way to do something like this.
I know that I can use the screencapture function, but I'm unsure of how to get the exact coordinates and size of the OpenGL area of the window (not the title bar/surrounding window stuff).
If anybody could help me out that would be awesome.
Or if anybody can think of an easier solution than AutoIt, and can point me in the right direction, that'd be great too.
EDIT: I also don't have access to the source code of the sample output program.
AutoIt is a pretty good tool for this job. I think you already found the _ScreenCapture in the help file, it has parameters for: X left, Y top, X right and Y bottom coordinates. However, the _ScreenCapture function stores to a file. I've made a library where you can capture part of the screen, or a window, and save this to memory. Then you can get the pixel colors from the memory and compare them to your existing pixels. You can find it here: http://www.autoitscript.com/forum/topic/63318-get-or-read-pixel-from-memory-udf-pixelgetcolor-au3/
The part of a window which does not include the titlebar and the borders is called the 'client area'. You can get the width and the height of the client area with the WinGetClientSize. Alternatively, you can use ControlGetPos on the OpenGL control to get the X and Y relative to the window, and the width and height of the OpenGL control. Combined with WinGetPos you should be able to calculate the values you need for _ScreenCapture. You should be able to find out a good approach if you use the "AutoIt window info" tool.
Finally, a simple and short solution which gives you little control, but might be just what you need, is the PixelChecksum function. Once you have the coordinates of the OpenGL part, you can use PixelChecksum and get a value corresponding to the pixels of the screen (a checksum of the pixels). You can then compare this value to a pre-recorded value to tell whether the pixels on the screen are exactly the same. Check the Autoit help file of PixelChecksum for an example.
If you want to capture data from an OpenGL buffer, here is how you can do it with legacy OpenGL (version 1.2 or so)
glFinish();
glReadBuffer(GL_FRONT);
glPixelStorei(GL_PACK_ALIGNMENT, 4);
glPixelStorei(GL_PACK_ROW_LENGTH, 0);
glPixelStorei(GL_PACK_SKIP_ROWS, 0);
glPixelStorei(GL_PACK_SKIP_PIXELS, 0);
glReadPixels(ox, oy, w, h, mode, GL_UNSIGNED_BYTE, img);
where:
ox and oy are origin x and y
w and h are width and height
mode is the mode, like GL_BGR if you want to save to BMP
img is a pointer to unsigned int * to copy the image to
You can search for glReadPixels on the internet and see the reference for more information.
Related
I'm Using a Wrapper Library in GMS2 That was made back in GM6 Days (gamemaker) Someone was able to wrap majority of the win32API to use in GM6-8. There is only 1 odd instance in where the WinAPI system seems to mess up when drawing the controls to the Main Application Window.
The desired goal is to draw an image to an Child window and draw a grid defining it's splitting according to the user input EX: 16x16 and having the user select squares VIA Mouse Click + Dragging over the boxes.
Unfortunately I have little to no experience in win32API so i'm a bit lost as to where to start.
Looking over the documentation it looks like he left majority of the script names of the DLL to mimic the format of that when calling in C++ or C (just my assumptions).
From His Documentation he has things like "Drawing System" Which Contains things like "Move Item","Add Line","Add Graphic Buffer" etc... and then other Graphic Buffer functions. But then theres the "Draw" functions which has things like "Draw Fill Rect , DrawSelectObj" etc... he doesn't really provide examples so i'm unsure as to how to use these things together to get my desired results. What is the difference between a drawing system and a draw function? Do I have to use them in conjunction, along with the Graphics Buffer?
Can Someone point in the right direction of the necessary steps to get it done? An Example without code and just the function equivalent will suffice, I just need to know out of which functions to use and then later bind it to the Child Window.
An Example Code from his demo is something like this
GbGradient2 = API_GB_Create (105,105); //Graphics Buffer
DcGradient2 = API_GB_GetDC (GbGradient2);
API_Draw_Gradient (DcGradient2,0,0,105,105,0,c_yellow,c_lime);
BrGradient2 = API_Draw_CreatePatternBrush (API_GB_GetBitmap (GbGradient2));
API_Draw_Gradient (DcGradient2,0,0,105,105,0,c_red,65535);
BrGradient3 = API_Draw_CreatePatternBrush (API_GB_GetBitmap (GbGradient2));
hRectangle = API_DS_AddRectangle (2,5,5,105,105); // Adds a rectangle(Drawing System)
hEllipse = API_DS_AddEllipse (2,5,5,105,105);
hNoPen = API_Draw_CreatePen (PS_NULL,0,0);
API_DS_SetItemBrush (hRectangle,BrGradient2); // Sets the brush
API_DS_SetItemBrush (hEllipse,BrGradient3);
API_DS_SetItemPen (hRectangle,hNoPen); // Sets the pen
API_DS_SetItemPen (hEllipse,hNoPen);
API_Draw_Gradient (GbGradient2,0,0,16,16,0,c_yellow,c_lime);
Lookin at it a little more it looks like the draw functions are linked to GDI somehow.
since GMS2 is a cross platform tool , its windows-only functionality gas been removed.
you can make a nice GUI for that porpose by using GMS2 objects , as you have a little Xp
about Win32 API,this will be easier than that big stuffy coding
here are some tips ,
creating a window object with a rectangle sprite
creating ui objects at the create event of above object
adding some code to the global mouse event
I am trying to scale images/text etc using MM_ANISTROPIC and what I've done is the following (by the way if the syntax is a little weird, it's originally from delphi so treat the following as pseudocode)
I would expect the following code to produce a rectangle that is 70% of the width of the PaintBox and 30% of the height, yet it doesn't, instead it it noticeably too small.
SetMapMode(hdc,MM_ANISOTROPIC);
SetWindowExtEx(hdc,100,100,0);
SetViewportExtEx(hdc,70,30,0);
Rectangle(hdc, 0,0,PaintBox.width-1,PaintBox.Height-1);
if, on the other hand I change the code so that the SetWindowExtEx has 91 instead of 100 as its parameters (as shown below) then it works, which makes no sense to me at all...
SetMapMode(hdc,MM_ANISOTROPIC);
SetWindowExtEx(hdc,91,91,0);
SetViewportExtEx(hdc,70,30,0);
Rectangle(hdc, 0,0,PaintBox.width-1,PaintBox.Height-1);
My sanity test case was to add the following pseudocode
SetMapMode(hdc,MM_TEXT);
DrawLine(hdc,Round(PaintBox.width*0.7),0,Round(PaintBox.width*0.7),PaintBox.Height-1);
DrawLine(hdc,0,Round(PaintBox.height*0.3),PaintBox.width-1,Round(PaintBox.height*0.3));
I would have expected this to overwrite the lower / bottom edges of my original Rectangle but it does not unless I uses that 91,91 SetWindowExtEx.
Can anyone duplicate this?
FURTHER EDIT: Here is my exact original code I had given pseudo code before to make the question more accessible to non-delphi users but one of my commenters wanted full code to see if my contention that it was a delphi quirk was true or not.
The entire project consisted of a VCL form with a rectangular paintbox dropped on it centered so there was space all around it, and its onPaint event was set to the code below resulting in this image::
procedure TForm11.PaintBox2Paint(Sender: TObject);
var
hdc:THandle;
res:TPoint;
procedure SetupMapMode;
begin
SetMapMode(hdc,MM_ANISOTROPIC);
SetWindowExtEx(hdc,100,100,0);
SetViewportExtEx(hdc,70,30,0);
// These lines are required when we're painting to a TPaintBox but can't be used
// if we're paiting to a TPanel and they were NOT in my original question but only
// got added as part of the answer
// SetViewportOrgEx(hdc,PaintBox2.Left,PaintBox2.Top,#ZeroPoint);
// SetWindowOrgEx(hdc,0,0,#ZeroPoint);
end;
begin
//draw a rectangle to frame the Paintbox Surface
PaintBox2.Canvas.Pen.Style:=psSolid;
PaintBox2.Canvas.Pen.width:=2;
PaintBox2.Canvas.Pen.Color:=clGreen;
PaintBox2.Canvas.Brush.Style:=bsClear;
PaintBox2.Canvas.Rectangle(0,0,PaintBox2.Width-1,PaintBox2.Height-1);
PaintBox2.Canvas.Brush.Style:=bsSolid;
//initialize convenience variable
hdc:=PaintBox2.Canvas.Handle;
SetTextAlign(hdc,TA_LEFT);
//as doing things to the PaintBox2.Canvas via Delphi's interface tends to reset
//everything, I'm ensuring the map mode gets set **immediately** before
//each drawing call
SetupMapMode;
/// Draw Text at the bottom of the PaintBox2.Canvas (though as it's mapped it
/// SHOULD be 1/3 of the way down and much smaller instead)
TextOut(hdc,200,PaintBox2.Height-PaintBox2.Canvas.TextHeight('Ap'),'Hello, World!',13);
PaintBox2.Canvas.Pen.Color:=clblue;
PaintBox2.Canvas.Brush.Style:=bsClear;
//ensure it's set before doing the rectangle
SetupMapMode;
// Redraw the same rectangle as before but in the mapped mode
Rectangle(hdc, 0,0,PaintBox2.Width-1,PaintBox2.Height-1);
PaintBox2.Canvas.Brush.Style:=bsSolid;
//reset the map mode to normal
SetMapMode(hdc,MM_Text);
//draw text at the "same" position as before but unmapped...
TextOut(hdc,200,PaintBox2.Height-PaintBox2.Canvas.TextHeight('Ap'),'Goodbye, World!',15);
//Draw lines exactly at 70% of the way across and 30% of the way down
//if this works as expected they should overwrite the right and bottom
//borders of the rectangle drawn in the mapped mode
PaintBox2.Canvas.Pen.Color:=RGB(0,255,255);
PaintBox2.Canvas.MoveTo(Round(PaintBox2.Width*0.7),0);
PaintBox2.Canvas.LineTo(Round(PaintBox2.Width*0.7),PaintBox2.Height);
PaintBox2.Canvas.MoveTo(0,Round(PaintBox2.Height*0.3));
PaintBox2.Canvas.LineTo(PaintBox2.Width,Round(PaintBox2.Height*0.3));
end;
Okay, I don't know WHY the following is necessary -- it may be a Delphi quirk, the fact that I'm using a TPaintBox with is a TGraphicControl rather than a Component, or if I'm missing out on some fundamental concept on how this whole mapping mode works, BUT if I add the following code:
ZeroPoint:=TPoint.Zero;
SetViewportOrgEx(hdc,PaintBox1.Left,PaintBox1.Top,#ZeroPoint);
SetWindowOrgEx(hdc,0,0,#ZeroPoint);
Then it all displays as expected. Anyone have any explanations as to why this is necessary?
EDIT: Okay, I've got a PARTIAL explanation. It has to do with the control I was painting on being a TPaintBox, which is a TGraphic control rather than a TWinControl. To wit:
TGraphicControl is the base class for all lightweight controls.
TGraphicControl supports simple lightweight controls that do not need the ability to accept keyboard input or contain other controls. Since lightweight controls do not wrap Windows screen objects, they are faster and user fewer resources than controls based on TWinControl.
As such, although they APPEAR to have a separate canvas, I have this sneaking feeling that they are really sharing the form's canvas which is why, when I switched to a TWinControl descendant, which DOES own its own Windows DC, then the display worked as expected without setting the ViewpointOrg.
So it was a Delphi quirk after all...!
I followed this post to play with OpenGL (programmable pipeline) on Ruby
Basically, I'm just trying to create a blue window, and here's the code.
Ray::GL.major_version = 3
Ray::GL.minor_version = 2
Ray::GL.core_profile = true # if you want/need one
window = Ray::Window.new("Test Window", [800, 600])
window.make_current
glClearColor(0, 0, 1, 1);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glEnable(GL_DEPTH_TEST);
Instead, I got a white window created. This indicated that I was missing something, but I couldn't figure out what I was missing as the resources for OpenGL on Ruby seemed limited. I have been searching all over the web, but all I found was fixed-pipeline OpenGL stuff for Ruby.
Yes, I could use Ray's built-in functions to set the background color and draw stuff, but I didn't want to do that. I just wanted to use Ray to setup the window, then called OpenGL APIs directly. However, I couldn't figure out what I was missing in the code above.
I would greatly appreciate any hint or pointer to this (maybe I needed to swap the buffer? but then I didn't know how to do it with Ray). Is there any body familiar with using Ray that can give me some hints on this?
Or, are there any other tools that would allow me to setup OpenGL binding (for none fixed-pipeline)?
It would appear that you set the clear color to be blue, then cleared the back buffer to make it blue. But, as you said, you have not swapped the buffers to put the back buffer onto your screen. As far as swapping buffers goes, here's another answer from stack overflow
"Swapping the front and back buffer of a double buffered window is a function provided by the underlying graphics system, i.e. Win32 GDI, or X11 GLX. The function's you're looking for are wglSwapBuffers and/or glXSwapBuffers. On MacOS X NSOpenGLViews are automatically swapped.
However most likely you're using some framework, like GLUT, GLFW or Qt, which provide a portable wrapper around those functions. Read the framework's documentation."
I've never used Ray, so I'd say just keep rooting around in the documentation or look through example projects to see how buffer swapping is done.
I am starting to play with wxErlang on XP, and am looking for a method of getting the screens dimension, so that I can cause my app to be drawn on the lower right hand corner of the screen. The wxErlang documentation seems to have an undue number of references to the wxWidgets c++ external documentation.
After Googling for a bit I ended up here, which seems to describe what I am looking for.
void wxClientDisplayRect
(
int * x,
int * y,
int * width,
int * height
);
Returns the dimensions of the work area on the display.
On Windows this means the area not covered by the taskbar, etc. Other platforms are currently defaulting to the whole display until a way is found to provide this info for all window managers, etc.
Include file:
#include <wx/gdicmn.h>
After searching the wxErlang doc, I haven't found anything corresponding to this function, nor recognized any hint of what should be used.
How does one get the screen dimensions, using wxErlang, so the window being drawn, can be set to the lower right hand corner of the screen?
It can't be done, hence it is a good reason to not use it.
I am developing an OpenGL application that has two working modes: windowed mode and full screen.
The app displays several graphic objects using OpenGL and writes some text strings using that same API. The program displays the texts strings in its intended positions when running as a windowed application, but when running full screen the text strings are displayed in an upper position that its intended position.
The app creates the fonts using wglUseFontBitmap and displays the text strings with glCallLists (it sets the text position using glRasterPos2i). Before the text is displayed I adjust the text position adding an offset to the Y coord. I get that offset using the GetDCOrgEx Win32 API call.
I think you have to call GetDCOrgEx again after getting in fullscreen mode, or do you already do this? It would help if you could post the code where you call GetDCOrgEx and calculate the Y offset.
EDIT: Another idea: Could it be that you can use the same Y offset, but negative? Or perhaps calculate Y position and then use height-ypos? There's some source code here that uses glRasterPos2i different when in fullScreen:
if(!state->fullScreen)
// if fullScreen (don't forget the image/GL y-coord vertical flip)
glRasterPos2i((w - state->img->cols())/2, (h - state->img->rows())/2);
else
// for non-fullscreen images
glRasterPos2i(0,h);
Schnaader, thanks a lot for your answers.
I have solved the problem modifying how I calculate the offset that I need to add to the Y coord. Now the offset is calculated with the following code:
m_iYOffset = GetSystemMetrics(SM_CYCAPTION) + GetSystemMetrics(SM_CYBORDER);
The above code solves the problem for my application.
Here's the code to calculate the Y offset:
POINT vOffset;
m_hdc = GetDC(m_hWnd);
if (m_hdc)
{
GetDCOrgEx(m_hdc, &vOffset);
m_iYOffset = vOffset.y;
}
The above code is called once the program has set up full screen mode. I tried to call GetDCOrgEx every time I need to write a text string, but the text is written at the same positions that when GetDCOrgEx is called only once.