I am playing around, trying to make a little JavaFX application to visualize data received via the serial port from an arduino-based board and some sensors.
After adding some live-updating LineGraphs, I am currently trying to display the roll, pitch and yaw values received from the micro-controller, by rotating a simple box-element.
I have one thread calling a function every x ms, which stores the incoming data into an ObservableList with an changeListener and calls the controller based function to update/rotate the orientation of the box.
Since the calculation of the angles is allready done on the micro-controller, I would like to rotate the box to the received absolute orientation.
From what I've understand so far, I can't simply rotate from any previous orientation to a new absolute one, but only change the orientation relatively to the previous one.
I came up with the following idea to just subtract the last roll/pitch/yaw values from the penultimate one of the observableList.
Data dataTmp = observableList.get(observableList.size()-2);
Data dataTmp2 = observableList.get(observableList.size()-1);
newRoll = dataTmp2.getRoll() - dataTmp.getRoll();
newPitch = dataTmp2.getPitch() - dataTmp.getPitch();
newYaw = dataTmp2.getYaw() - dataTmp.getYaw();
Platform.runLater(new Runnable() {
#Override
public void run() {
controller.setToPosition(newRoll, newPitch, newYaw);
}
});
//...
This only works out to a certain extent. I still want to rotate to the absolute position received from the micro-controller.
So my question is this: Is there a way to reset the orientation of the box to e.g. 0, 0, 0 from where I could rotate to my new absolute orientation? Simply removing the box and adding a new one did not work out at all.
group.getChildren().remove(box);
box = new Box(300,50,300);
group.getChildren().add(box);
Thank you in advance for any ideas or even solutions. If you need more information or code snippets let me know.
Referring to this example, an onMouseMoved handler rotates the red Box around the x and y axes as the mouse moves. The following onKeyPressed handler restores the red Box to its original position when the Z key is pressed. Each handler uses the setAngle() method of the Rotate class.
scene.setOnKeyPressed(e -> {
if (e.getCode() == KeyCode.Z) {
content.rx.setAngle(0);
content.ry.setAngle(0);
content.rz.setAngle(0);
}
});
Similarly, your setToPosition() implementation can invoke setAngle() to establish the new roll, pitch and yaw values.
Before:
After:
More subtly, verify that you synchronize access to any data shared between your data acquisition thread and the JavaFX application thread. This example illustrates a Task<Canvas>, while your application might instead implement a Task<Point3D>, where a Point3D holds the roll, pitch and yaw values.
I have a player and a few NPCs.
The NPCs have random movement, and I control my players movement. They both have RigidBody2D to deal with physics and BoxCollider2D to deal with Collisions.
However, when I walk into a NPC my player pushes it. Same thing if a NPC moves into my player while the player stands still.
I can't set the mass of either object to some extreme number since that will interfere with how they behave with other objects in my game.
What I want:
When an NPC collides with the player, the NPC stops (I get this effect if I set player mass to ex. 1000, but then the player can push the NPC, which I dont want), and the NPC acts as a "wall", i.e it doesnt move, but nor can the player push it around. How can I do this?
EDIT: So I created my own method for it:
void OnCollisionEnter2D(Collision2D other){
if (other.gameObject.name == "Player") {
collidedWithPlayer = true; //we only move if !collidedWithPlayer
isMoving = false; //stop moving
myRigidBody.mass = 1000; //turn NPC into "wall"
}
}
void OnCollisionExit2D(Collision2D other){
if (other.gameObject.name == "Player") {
collidedWithPlayer = false;
waitCounter = waitTime; //stop NPC from starting to move right after we exit
myRigidBody.mass = 1;
}
}
I mean this works, but is there no native method to do this?
What you are trying to do is essentially use a "realistic" physics engine to create rather unrealistic physics. That's why it's not supported by Unity's built-in functions. Furthermore, you are correct in assuming that messing with the object masses is not a good idea.
Here's one suggestion that avoids playing with mass. It's a bit kludgey, but give it a try and see if it works for you. (I assume your player rigidbody is not Kinematic?)
Step 1: Create 2 new layers; call them NPCWall and PlayerWall. Setup 2D physics so that player collides with NPCWall and NPC collides with PlayerWall, but player does not collide with NPCs. (If your NPCs and player are on the same layer, then of course put them on 2 separate layers.)
Step 2: Create an NPCWall prefab that uses the same kind of collider as the NPCs. I assume you only have one size of NPC. Likewise, create a PlayerWall prefab that uses the same kind of collider as the player. Set the NPCWall prefab to NPCWall layer, and PlayerWall prefab to PlayerWall layer.
Step 3: We can't parent the NPCWall to the NPC, because it would end up as part of the rigidbody. Therefore add a simple script to the NPCWall and PlayerWall:
public class TrackingWall
{
//This invisible wall follows an NPC around to block the player.
//It also follows the player around to block NPCs.
Transform followTransform;
public void Init(Transform targetTrans)
{
followTransform = targetTrans;
transform.position = followTransform.position;
transform.rotation = followTransform.rotation;
}
void Update()
{
if (followTransform == null)
Destroy(gameObject);
transform.position = followTransform.position;
transform.rotation = followTransform.rotation;
}
}
Step 4: In the NPC and player scripts:
TrackingWall myWallPrefab;
void Start()
{
[whatever else you are doing in Start()]
TrackingWall myWall = Instantiate<TrackingWall>(myWallPrefab);
myWall.Init(transform);
}
Obviously, for NPCs, myWallPrefab should be set to the NPCWall prefab, and for players, myWallPrefab should be set to the PlayerWall prefab.
In theory this should give each character an impenetrable, immovable wall that only moves when they do, prevents other characters from pushing them, and cleans itself up when they are destroyed. I can't guarantee it will work though!
recently i start to learn Qt and now i'm working on GCS project that it must have a map with some tiled imges and and some graphics item like Plan,the path and also on over off all some gauge.
so we have 3 kind of item:
Tiled map in the background so that its change by scrolling .
in the middle there is a picture of airplane that move by gps changes and also its way .
on the all on off these items there 3 or 4 gauge like speed meter, horizontal gauge and altimeter gauge there are must be solid in somewhere of graphicsview and not change when scrolling down/up or left right
The question is what is the best way to implement this ?
here is first look of my project:
in first look gauge are not over map but i want to be ! i want to have bigger map screen with gauges include it !
And here is map updater code :
void mainMap::update()
{
m_scene->clear();
QString TilePathTemp;
QImage *imageTemp = new QImage();
int X_Start=visibleRect().topLeft().x()/256;
int X_Num=qCeil((float)visibleRect().bottomRight().x()/256.0f-(float)visibleRect().topLeft().x()/256.0f);
int Y_Start=visibleRect().topLeft().y()/256;
int Y_Num=qCeil((float)visibleRect().bottomRight().y()/256.0f-(float)visibleRect().topLeft().y()/256.0f);
LastCenterPoint->setX(visibleRect().center().x());
LastCenterPoint->setY(visibleRect().center().y());
X_Start=(X_Start-X_MAP_MARGIN)>0?(X_Start-X_MAP_MARGIN):0;
Y_Start=(Y_Start-Y_MAP_MARGIN)>0?(Y_Start-Y_MAP_MARGIN):0;
X_Num+=X_MAP_MARGIN;
Y_Num+=Y_MAP_MARGIN;
qDebug()<<"XS:"<<X_Start<<" Num:"<<X_Num;
qDebug()<<"YS:"<<Y_Start<<" Num:"<<Y_Num;
for(int x=X_Start;x<=X_Start+X_Num;x++){
for(int y=Y_Start;y<=Y_Start+Y_Num;y++){
if(Setting->value("MapType",gis::Hybrid).toInt()==gis::Hybrid) TilePathTemp=Setting->value("MapPath","/Users/M410/Documents/Map").toString()+"/Hybrid/gh_"+QString::number(x)+"_"+QString::number(y)+"_"+QString::number(ZoomLevel)+".jpeg" ;
else if(Setting->value("MapType",gis::Sattelite).toInt()==gis::Sattelite) TilePathTemp=Setting->value("MapPath","/Users/M410/Documents/Map").toString()+"/Sattelite/gs_"+QString::number(x)+"_"+QString::number(y)+"_"+QString::number(ZoomLevel)+".jpeg" ;
else if(Setting->value("MapType",gis::Street).toInt()==gis::Street) TilePathTemp=Setting->value("MapPath","/Users/M410/Documents/Map").toString()+"/Street/gm_"+QString::number(x)+"_"+QString::number(y)+"_"+QString::number(ZoomLevel)+".jpeg" ;
QFileInfo check_file(TilePathTemp);
// check if file exists and if yes: Is it really a file and no directory?
if (check_file.exists() && check_file.isFile()) {
// qDebug()<<"Exist!";
imageTemp->load(TilePathTemp);
QPixmap srcImage = QPixmap::fromImage(*imageTemp);
//QPixmap srcImage("qrc:/Map/File1.jpeg");
QGraphicsPixmapItem* item = new QGraphicsPixmapItem(srcImage);
item->setPos(QPointF(x*256, y*256));
m_scene->addItem(item);
// centerOn( width() / 2.0f , height() / 2.0f );
} else {
qDebug()<<"NOT Exist!";
}
}
}
Really, you should consider using QML. The advantage of using QML instead of QGraphicsView is you can iterate a lot faster than if you were working directly in C++. The primary downside is generally increased memory usage and incompatibility with QWidgets.
So if you need unique graphics, and very little "standard widget" stuff, you should use QML first and then QGraphicsView ONLY IF requirements dictate it.
Specific to your project though, Qt has a Map type which could be useful: https://doc.qt.io/qt-5/qml-qtlocation-map.html
I have a lineEdit I use so the user can enter a frequency interval,
// Making the lineedit objects only accept numbers and align it leftside
ui->frequency->setValidator(new QIntValidator(36, 1000, this));
ui->frequency->setAlignment(Qt::AlignRight);
It works fine to the top limit 1000 but the lower dos not. So I created an slot to control it,
// Control freqeuncy interval
void gui::f_interval()
{
QString f = ui->frequency->text();
freq = f.toInt();
if (freq < 36)
{
int status = QMessageBox::warning(this,"Warning","Invalid frequency interval",QMessageBox::Ok);
}
}
and connected it to the signal of the lineEdit,
// Control frequency interval
connect(ui->frequency, SIGNAL(editingFinished()), this, SLOT(f_interval()));
so that when the user enters a number lower than 36 it gets a warning dialog window.
But it doesn't seem to work. can anyone help me?
You want to connect with textChanged signal instead of editingFinished.
LE: also i don't remember having issues with validator, so can you provide more details, like Qt version, Os version, compiler, maybe see if the issue is reproduced in a sample project.
I am using a GDI+ Graphic to draw a 4000*3000 image to screen, but it is really slow. It takes about 300ms. I wish it just occupy less than 10ms.
Bitmap *bitmap = Bitmap::FromFile("XXXX",...);
//--------------------------------------------
// this part takes about 300ms, terrible!
int width = bitmap->GetWidth();
int height = bitmap->GetHeight();
DrawImage(bitmap,0,0,width,height);
//------------------------------------------
I cannot use CachedBitmap, because I want to edit the bitmap later.
How can I improve it? Or is any thing wrong?
This native GDI function also draws the image into the screen, and it just take 1 ms:
SetStretchBltMode(hDC, COLORONCOLOR);
StretchDIBits(hDC, rcDest.left, rcDest.top,
rcDest.right-rcDest.left, rcDest.bottom-rcDest.top,
0, 0, width, height,
BYTE* dib, dibinfo, DIB_RGB_COLORS, SRCCOPY);
//--------------------------------------------------------------
If I want to use StretchDIBits, I need to pass BITMAPINFO, But how can I get BITMAPINFO from a Gdi+ Bitmap Object? I did the experiment by FreeImage lib, I call StretchDIBits using FreeImageplus object, it draw really fast. But now I need to draw Bitmap, and write some algorithm on Bitmap's bits array, how can I get BITMAPINFO if I have an Bitmap object? It's really annoying -___________-|
If you're using GDI+, the TextureBrush class is what you need for rendering images fast. I've written a couple of 2d games with it, getting around 30 FPS or so.
I've never written .NET code in C++, so here's a C#-ish example:
Bitmap bmp = new Bitmap(...)
TextureBrush myBrush = new TextureBrush(bmp)
private void Paint(object sender, PaintEventArgs e):
{
//Don't draw the bitmap directly.
//Only draw TextureBrush inside the Paint event.
e.Graphics.FillRectangle(myBrush, ...)
}
You have a screen of 4000 x 3000 resolution? Wow!
If not, you should draw only the visible part of the image, it would be much faster...
[EDIT after first comment] My remark is indeed a bit stupid, I suppose DrawImage will mask/skip unneeded pixels.
After your edit (showing StretchDIBits), I guess a possible source of speed difference might come from the fact that StretchDIBits is hardware accelerated ("If the driver cannot support the JPEG or PNG file image" is a hint...) while DrawImage might be (I have no proof for that!) coded in C, relying on CPU power instead of GPU's one...
If I recall correctly, DIB images are fast (despite being "device independent"). See High Speed Win32 Animation: "use CreateDIBSection to do high speed animation". OK, it applies to DIB vs. GDI, in old Windows version (1996!) but I think it is still true.
[EDIT] Maybe Bitmap::GetHBITMAP function might help you to use StretchDIBits (not tested...).
Just a thought; instead of retrieving the width and height of the image before drawing, why not cache these values when you load the image?
Explore the impact of explicitly setting the interpolation mode to NearestNeighbor (where, in your example, it looks like interpolation is not actually needed! But 300ms is the kind of cost of doing high-quality interpolation when no interpolation is needed, so its worth a try)
Another thing to explore is changing the colour depth of the bitmap.
Unfortunately when I had a similar problem, I found that GDI+ is known to be much slower than GDI and not generally hardware accelerated, but now Microsoft have moved on to WPF they will not come back to improve GDI+!
All the graphics card manufacturers have moved onto 3D performance and don't seem interested in 2D acceleration, and there's no clear source of information on which functions are or can be hardware accelerated or not. Very frustrating because having written an app in .NET using GDI+, I am not happy to change to a completely different technology to speed it up to reasonable levels.
i don't think they'll make much of a different, but since you're not actually needing to resize the image, try using the overload of DrawImage that doesn't (attempt) to resize:
DrawImage(bitmap,0,0);
Like i said, i doubt it will make any difference, because i'm sure that DrawImage checks the Width and Height of the bitmap, and if there's no resizing needed, just calls this overload. (i would hope it doesn't bother going through all 12 million pixels performing no actual work).
Update: My ponderings are wrong. i had since found out, but guys comment reminded me of my old answer: you want to specify the destination size; even though it matches the source size:
DrawImage(bitmap, 0, 0, bitmap.GetWidth, bitmap.GetHeight);
The reason is because of dpi differences between the dpi of bitmap and the dpi of the destination. GDI+ will perform scaling to get the image to come out the right "size" (i.e. in inches)
What i've learned on my own since last October is that you really want to draw a "cached" version of your bitmap. There is a CachedBitmap class in GDI+. There are some tricks to using it. But in there end i have a function bit of (Delphi) code that does it.
The caveat is that the CachedBitmap can become invalid - meaning it can't be used to draw. This happens if the user changes resolutions or color depths (e.g. Remote Desktop). In that case the DrawImage will fail, and you have to re-created the CachedBitmap:
class procedure TGDIPlusHelper.DrawCachedBitmap(image: TGPImage;
var cachedBitmap: TGPCachedBitmap;
Graphics: TGPGraphics; x, y: Integer; width, height: Integer);
var
b: TGPBitmap;
begin
if (image = nil) then
begin
//i've chosen to not throw exceptions during paint code - it gets very nasty
Exit;
end;
if (graphics = nil) then
begin
//i've chosen to not throw exceptions during paint code - it gets very nasty
Exit;
end;
//Check if we have to invalidate the cached image because of size mismatch
//i.e. if the user has "zoomed" the UI
if (CachedBitmap <> nil) then
begin
if (CachedBitmap.BitmapWidth <> width) or (CachedBitmap.BitmapHeight <> height) then
FreeAndNil(CachedBitmap); //nil'ing it will force it to be re-created down below
end;
//Check if we need to create the "cached" version of the bitmap
if CachedBitmap = nil then
begin
b := TGDIPlusHelper.ResizeImage(image, width, height);
try
CachedBitmap := TGPCachedBitmap.Create(b, graphics);
finally
b.Free;
end;
end;
if (graphics.DrawCachedBitmap(cachedBitmap, x, y) <> Ok) then
begin
//The calls to DrawCachedBitmap failed
//The API is telling us we have to recreate the cached bitmap
FreeAndNil(cachedBitmap);
b := TGDIPlusHelper.ResizeImage(image, width, height);
try
CachedBitmap := TGPCachedBitmap.Create(b, graphics);
finally
b.Free;
end;
graphics.DrawCachedBitmap(cachedBitmap, x, y);
end;
end;
The cachedBitmap is passed in by reference. The first call to DrawCachedBitmap it cached version will be created. You then pass it in subsequent calls, e.g.:
Image imgPrintInvoice = new Image.FromFile("printer.png");
CachedBitmap imgPrintInvoiceCached = null;
...
int glyphSize = 16 * (GetCurrentDpi() / 96);
DrawCachedBitmap(imgPrintInvoice , ref imgPrintInvoiceCached , graphics,
0, 0, glyphSize, glyphSize);
i use the routine to draw glyphs on buttons, taking into account the current DPI. The same could have been used by the Internet Explorer team to draw images when the user is running high dpi (ie is very slow drawing zoomed images, because they use GDI+).
/*
First sorry for ma English, and the code is partly in polish, but it's simple to understand.
I had the same problem and I found the best solution. Here it is.
Dont use: Graphics graphics(hdc); graphics.DrawImage(gpBitmap, 0, 0); It is slow.
Use: GetHBITMAP(Gdiplus::Color(), &g_hBitmap) for HBITMAP and draw using my function ShowBitmapStretch().
You can resize it and it is much faster! Artur Czekalski / Poland
*/
//--------Global-----------
Bitmap *g_pGDIBitmap; //for loading picture
int gRozXOkna, gRozYOkna; //size of working window
int gRozXObrazu, gRozYObrazu; //Size of picture X,Y
HBITMAP g_hBitmap = NULL; //for displaying on window
//------------------------------------------------------------------------------
int ShowBitmapStretch(HDC hdc, HBITMAP hBmp, int RozX, int RozY, int RozXSkal, int RozYSkal, int PozX, int PozY)
{
if (hBmp == NULL) return -1;
HDC hdc_mem = CreateCompatibleDC(hdc); //utworzenie kontekstu pamięciowego
if (NULL == hdc_mem) return -2;
//Trzeba połączyć BMP z hdc_mem, tzn. umieścić bitmapę w naszym kontekście pamięciowym
if (DeleteObject(SelectObject(hdc_mem, hBmp)) == NULL) return -3;
SetStretchBltMode(hdc, COLORONCOLOR); //important! for smoothness
if (StretchBlt(hdc, PozX, PozY, RozXSkal, RozYSkal, hdc_mem, 0, 0, RozX, RozY, SRCCOPY) == 0) return -4;
if (DeleteDC(hdc_mem) == 0) return -5;
return 0; //OK
}
//---------------------------------------------------------------------------
void ClearBitmaps(void)
{
if (g_hBitmap) { DeleteObject(g_hBitmap); g_hBitmap = NULL; }
if (g_pGDIBitmap) { delete g_pGDIBitmap; g_pGDIBitmap = NULL; }
}
//---------------------------------------------------------------------------
void MyOpenFile(HWND hWnd, szFileName)
{
ClearBitmaps(); //Important!
g_pGDIBitmap = new Bitmap(szFileName); //load a picture from file
if (g_pGDIBitmap == 0) return;
//---Checking if picture was loaded
gRozXObrazu = g_pGDIBitmap->GetWidth();
gRozYObrazu = g_pGDIBitmap->GetHeight();
if (gRozXObrazu == 0 || gRozYObrazu == 0) return;
//---Uworzenie bitmapy do wyświatlaia; DO IT ONCE HERE!
g_pGDIBitmap->GetHBITMAP(Gdiplus::Color(), &g_hBitmap); //creates a GDI bitmap from this Bitmap object
if (g_hBitmap == 0) return;
//---We need to force the window to redraw itself
InvalidateRect(hWnd, NULL, TRUE);
UpdateWindow(hWnd);
}
//---------------------------------------------------------------------------
void MyOnPaint(HDC hdc, HWND hWnd) //in case WM_PAINT; DO IT MANY TIMES
{
if (g_hBitmap)
{
double SkalaX = 1.0, SkalaY = 1.0; //scale
if (gRozXObrazu > gRozXOkna || gRozYObrazu > gRozYOkna || //too big picture, więc zmniejsz;
(gRozXObrazu < gRozXOkna && gRozYObrazu < gRozYOkna)) //too small picture, można powiększyć
{
SkalaX = (double)gRozXOkna / (double)gRozXObrazu; //np. 0.7 dla zmniejszania; FOR DECREASE
SkalaY = (double)gRozYOkna / (double)gRozYObrazu; //np. 1.7 dla powiększania; FOR INCREASE
if (SkalaY < SkalaX) SkalaX = SkalaY; //ZAWSZE wybierz większe skalowanie, czyli mniejszą wartość i utaw w SkalaX
}
if (ShowBitmapStretch(hdc, g_hBitmap, gRozXObrazu, gRozYObrazu, (int)(gRozXObrazu*SkalaX), (int)(gRozYObrazu*SkalaX), 0, 0, msg) < 0) return;
Try using copy of Bitmap from file. FromFile function on some files returns "slow" image, but its copy will draw faster.
Bitmap *bitmap = Bitmap::FromFile("XXXX",...);
Bitmap *bitmap2 = new Bitmap(bitmap); // make copy
DrawImage(bitmap2,0,0,width,height);
I have made some researching and wasn't able to find a way to render images with GDI/GDI+ more faster than
Graphics.DrawImage/DrawImageUnscaled
and at the same time simple like it.
Till I discovered
ImageList.Draw(GFX,Point,Index)
and yeah it's really so fast and simple.