how to animate picture without making it flicker using wxWidgets in erlang? - erlang

I am trying to make images seems like moving. I clear the screen and put the images back on it, but the screen is flickering a lot.
Is there a way to make it seems like moving without flicker that much?
the "draw_asteroids" is called every 100 ms since I want the movement of the image to be as much as continuous as possible,
plus i have many other elements that move on screen as well (the code is similar to the spaceship).
my code:
start->
Wx = wx:new(),
Frame = wxFrame:new(Wx, -1, "Main Game Frame", [{size, {?max_x, ?max_y}}]),
MenuBar = wxMenuBar:new(),
wxFrame:setMenuBar(Frame, MenuBar),
Panel = wxPanel:new(Frame),
wxFrame:connect(Panel, paint),
Image = wxImage:new("asteroid.png"),
wxFrame:show(Frame),
loop(Panel, {0,0}, Image).
loop(Panel, {X,Y}, Image)->
receive
after 100 ->
{NewX,NewY} =claculateNewPosition({X,Y}),
clearScreen(Frame, Panel),
draw_asteroids(Panel, {NewX,NewY}, Image),
loop(Panel, {NewX,NewY}, Image)
end.
draw_asteroids(Panel, {X, Y}, Image) ->
Pos = {round(X), round(Y)},
ClientDC = wxClientDC:new(Panel),
Bitmap = wxBitmap:new(Image),
wxDC:drawBitmap(ClientDC, Bitmap, Pos),
wxBitmap:destroy(Bitmap),
wxClientDC:destroy(ClientDC).
clearScreen(Frame, Panel)->
NewPanel = wxPanel:new(Frame),
wxWindow:setSize(Frame, {?max_x+1, ?max_y+1}),
wxWindow:setSize(Frame, {?max_x, ?max_y}),
NewPanel.

I have solved this in both windows and linux doing the following:
in the init function: create a bitmap of the expected size, and a memoryDC form it:
Bitmap = wxBitmap:new(W,H),
MemoryDC = wxMemoryDC:new(Bitmap),
...
I also define an area where to put the bitmap and I connect it to some event, at least paint:
Panel = wxPanel:new(Board, [{size,{W,H}}]),
wxPanel:connect(Panel, paint, [callback]),
wxPanel:connect(Panel, left_up, []),
wxPanel:connect(Panel, right_down, []),
wxPanel:connect(Panel, middle_down, []),
I use to store the modification request in a list which will be processed later.
then I use an external event to refresh the screen, that trigger window refresh The option {eraseBackground,false} is very important to avoid flickering:
do_refresh(Cb,Z,PMa,PFe,PM,BMa,BFe,BM,P,MemoryDC) ->
wx:batch(fun () ->
Cb1 = lists:reverse(Cb),
[cell(MemoryDC,PMa,PFe,PM,BMa,BFe,BM,State,Cell,Sex,Z) || {State,Cell,Sex} <- Cb1],
wxWindow:refresh(P,[{eraseBackground,false}])
end).
I use this external event for 2 reasons:
have a regular refresh rate that I master
allow many processes to update independently the bitmap (storing the request in the list)
I use an external timer which call a refresh function which collect the list of modification asked by other processes, execute them in order in the memoryDC, and then trigs the paint event using the window:refresh/2 function. The whole function is executed in a batch to improve performances.
And in the redraw event I simply "blit" the panel (note that this function can refresh a part of the panel to reduce the execution time, I didn't use this optimization at first, and the result was fast and smooth enough so I kept my initial code) :
handle_sync_event(#wx{event = #wxPaint{}}, _wxObj, #state{panel=Panel, memoryDC=MDC, w=W, h=H}) ->
redraw(Panel,MDC,W,H).
redraw(Panel, MemoryDC, W, H) ->
DC = wxPaintDC:new(Panel),
wxDC:blit(DC,{0,0},{W,H},MemoryDC,{0,0}),
wxPaintDC:destroy(DC).
It seems to be required to create and destroy the PaintDC.
This code do not manage the resize of the window (no sense in my application), but it should be easy to extend.

Related

Why is the server response after a Drag&Drop so large and slow

I'm having some performance issues dragging cards between grids. From a backend perspective, storing the data from the grids after a change takes about 200ms.
But then, when the backend work seems to be done, it takes another 2,5 seconds for the frontend to get the response from the request. The request that's taking so long contact 2 rpc events: grid-drop and grid-dragend.
The response is also unusually large I think. Just to give you an idea, see screenshot ... notice the tiny scrollbar at the right. 🙂
TTFB is 2,42s, download size about half a MB.
Any ideas what's going on here and how I can eliminate this?
I'm using Vaadin 21.0.4, spring boot 2.5.4.
Steps I've taken to optimise performance:
Optimize db query + indexing
Use #cacheable where possible
Implemented the cards using LitElement
This is the drop listener:
ComponentEventListener<GridDropEvent<Task>> dropListener = event -> {
if (dragSource != null) {
// The item ontop or below where the source item is dropped. Used to calculate the index of the newly dropped item(s)
Optional<Task> targetItem = event.getDropTargetItem();
// if the item is dropped on an existing row and the dragged item contains the same items that's being dropped.
if (targetItem.isPresent() && draggedItems.contains(targetItem.get())) {
return;
}
// Add dragged items to the grid of the target room
Grid<Task> targetGrid = event.getSource();
Optional<Room> room = dayPlanningView.getRoomForGrid(targetGrid);
// The items of the target Grid. Using listdataview so this would not retrigger the query
List<Task> targetItems = targetGrid.getListDataView().getItems().toList();
// Calculate the position of the dropped item
int index = targetItem.map(task -> targetItems.indexOf(task)
+ (event.getDropLocation() == GridDropLocation.BELOW ? 1 : 0))
.orElse(0);
room.ifPresent(r -> service.plan(draggedItems, r, index, dayPlanningView.getSelectedDate()));
// send event to update other users
Optional<ScheduleUpdatedEvent> scheduleUpdatedEvent = room.map(r -> new ScheduleUpdatedEvent(PlanningMasterDetailView.this, r.getId()));
scheduleUpdatedEvent.ifPresent(Broadcaster::broadcast);
// remove items from the source grid. using list provider so items can be removed without DB round-trip.
productionOrderGrid.getListDataView().removeItems(draggedItems);
}
};
I'm a bit stuck now, as I'm kinda out of ideas 😦
Thanks
You should use the TemplateRenderer/LitRenderer instead of the ComponentRenderer because the generated server-side components are affecting the performance:
Read more here: https://vaadin.com/blog/top-5-most-common-vaadin-performance-pitfalls-and-how-to-avoid-them

Printing an image to a dye based application

I am learning about fluid dynamics (and Haxe) and have come across this awesome project and thought I would try to extend to it to help me learn. A demo of the original project in action can be seen here.
So far, I have created a side menu of items containing different shapes. When the user clicks on one of the shapes, then, clicks onto the canvas, the image selected should be imprinted onto the dye. The user will then move the mouse and explore the art etc.
To try and achieve this I did the following:
import js.html.webgl.RenderingContext;
function imageSelection(): Void{
document.querySelector('.myscrollbar1').addEventListener('click', function() {
// twilight image clicked
closeNav();
reset();
var image:js.html.ImageElement = cast document.querySelector('img[src="images/twilight.jpg"]');
gl.current_context.texSubImage2D(cast fluid.dyeRenderTarget.writeToTexture, 0, Math.round(mouse.x), Math.round(mouse.y), RenderingContext.RGB, RenderingContext.UNSIGNED_BYTE, image);
TWILIGHT = true;
});
After this call, inside the update function, I have the following:
override function update( dt:Float ){
time = haxe.Timer.stamp() - initTime;
performanceMonitor.recordFrameTime(dt);
//Smaller number creates a bigger ripple, was 0.016
dt = 0.090;//#!
//Physics
//interaction
updateDyeShader.isMouseDown.set(isMouseDown && lastMousePointKnown);
mouseForceShader.isMouseDown.set(isMouseDown && lastMousePointKnown);
//step physics
fluid.step(dt);
particles.flowVelocityField = fluid.velocityRenderTarget.readFromTexture;
if(renderParticlesEnabled){
particles.step(dt);
}
//Below handles the cycling of colours once the mouse is moved and then the image should be disrupted into the set dye colours.
}
However, although the project builds, I can't seem to get the image imprinted onto the canvas. I have checked the console log and I can see the following error:
WebGL: INVALID_ENUM: texSubImage2D: invalid texture target
Is it safe to assume that my cast for the first param is not allowed?
I have read that the texture target is the first parameter and INVALID_ENUM in particular means that one of the gl.XXX parameters are just flat out wrong for that particular function.
Looking through to the file writeToTexture is declared as so: public var writeToTexture (default, null):GLTexture;. WriteToTexture is a wrapper around a regular webgl handle.
I am using Haxe version 3.2.1 and using Snow to build the project. WriteToTexture is defined inside HaxeToolkit\haxe\lib\gltoolbox\git\gltoolbox\render
writeToTexture in gltoolbox is a GLTexture. With snow and snow_web, this is defined in snow.modules.opengl.GL as:
typedef GLTexture = js.html.webgl.Texture;
So we're simply dealing with a js.html.webgl.Texture here, or WebGLTexture in native JS.
Which means that yes, this is definitely not a valid value for texSubImage2D()'s target, which is specified to take one of the gl.TEXTURE_* constants.
A GLenum specifying the binding point (target) of the active texture.
From this description it's obvious that the parameter isn't actually for the texture itself - it merely gives some info on how the active texture should be used.
The question then becomes how the "active" texture can be set. bindTexture() can be used for this.

How to close a programm in Erlang with WxWidgets?

I have a problem to close a program in Erlang. I use wxWidgets.
-module(g).
-compile(export_all).
-define(height, 500).
-define(width, 500).
-include_lib("wx/include/wx.hrl").
-define(EXIT,?wxID_EXIT).
init() ->
start().
start() ->
Wx = wx:new(),
Frame = wxFrame:new(Wx, -1, "Line", [{size, {?height, ?width}}]),
setup(Frame),
wxFrame:show(Frame),
loop(Frame).
setup(Frame) ->
menuBar(Frame),
wxFrame:connect(Frame, close_window).
menuBar(Frame) ->
MenuBar = wxMenuBar:new(),
File = wxMenu:new(),
wxMenuBar:append(MenuBar,File,"&Fichier"),
wxFrame:setMenuBar(Frame,MenuBar),
Quit = wxMenuItem:new ([{id,400},{text, "&Quit"}]),
wxMenu:append (File, Quit).
loop(Frame) ->
receive
#wx{event=#wxCommand{type=close_window}} ->
io:format("quit icon"),
wxWindow:close(Frame,[]);
#wx{id=?EXIT, event=#wxCommand{type=command_menu_selected}} ->
io:format("quit file menu"),
wxWindow:close(Frame,[])
end.
But the program doesn't close; neither the quit icon or Quit from the menu do anything.
You're almost there, but there's a few mistakes.
First, there's never any event being generated for your quit selection on your mention, you need to use connect again, like this:
Quit = wxMenuItem:new ([{id,400},{text, "&Quit"}]),
wxFrame:connect(Frame, command_menu_selected),
Now you have an event for each of the quit methods, but neither of them is working still.
The event for your quit icon isn't matching because you have the wrong event type in your pattern match, and the event for the menu quit selection isn't matching because you're looking for an ID of ?EXIT, which is defined as ?wxID_EDIT, which is defined as.. well clearly not 400, the ID you used when you created your quit menu item. So your receive clause needs to be changed to something like this:
receive
#wx{event=#wxClose{type=close_window}} ->
io:format("quit icon"),
wxFrame:destroy(Frame);
#wx{id=400, event=#wxCommand{type=command_menu_selected}} ->
io:format("quit file menu"),
wxFrame:destroy(Frame)
end.
In addition to Michael's answer regarding using connect/3 to listen for menu commands, nearly any frame will require a few standard event connections to behave the way you expect them to on closing in addition to whatever specific things you have going on. Note that this is connecting to the close_window event and using the option {skip, true}. This is so the signal doesn't stop propagating before it hits the part of Wx that will handle it the way you expect (one click to close) instead of requiring two clicks to close the frame on some platforms.
The basic skeleton often looks like this:
init(Args) ->
Wx = wx:new(),
Frame = wxFrame:new(Wx, ?wxID_ANY, ""),
% Generate whatever state the process represents
State = some_state_initializer(Args),
% Go through the steps to create your widget layout, etc.
WidgetReferences = make_ui(Frame),
% The standardish connects nearly any frame will need.
ok = wxFrame:connect(Frame, close_window, [{skip, true}]),
ok = wxFrame:connect(Frame, command_button_clicked),
ok = wxFrame:connect(Frame, command_menu_selected),
% Add more connects here depending on what you need.
% Adjust the frame size and location, if necessary
Pos = initial_position(Args),
Size = initial_size(Args),
ok = wxFrame:move(Frame, Pos),
ok = wxFrame:setSize(Frame, Size),
wxFrame:show(Frame),
% Optional step to add this frame to a UI state manager if you're
% writing a multi-window application.
ok = gui_manager:add_live(self()),
% Required return for wx_object behavior
{Frame, State}.
Digressing a bit from the original, but strongly related...
Many wxWidgets application have something very similar to this, customized as necessary not by writing all that out again, but by defining your own callback module and passing it in as an argument:
init({Mod, Args}) ->
% ...
PartialState = blank_state([{mod, Mod}, {frame, Frame}, {wx, Wx}]),
State = Mod:finalize(PartialState, Args),
Where blank_state/1 accepts a proplist and returns whatever the actual data structure will be later (usually a record at this level, that looks something like #s{mod, frame, wx, widgets, data}), and Mod:finalize/2 takes the incomplete state and the initial args and returns a completed GUI frame plus whatever program state it is supposed to manage -- in particular the widgets data structure that carries references to any GUI elements you will need to listen for, match on, or manipulate later.
Later on you have some very basic generic handlers all frames might need to deal with, and pass any other messages through to the specific Mod:
handle_call(Message, From, State = #s{mod = Mod}) ->
Mod:handle_call(Message, From, State).
handle_cast(blit, State) ->
{ok, NewState} = do_blit(State),
{noreply, NewState};
handle_cast(show, State) ->
ok = do_show(State),
{noreply, State};
handle_cast(Message, State = #s{mod = Mod}) ->
Mod:handle_cast(Message, State).
In this case do_blit/1 winds up calling Mod:blit/1 in the callback module which rebuilds and refreshes the GUI, rebuilding it from zero by calling a function that does that within wx:batch/1 to make it appear instant to the user:
blit(State) ->
wx:batch(fun() -> freshen_ui(State) end).
If you have a lot of elements to change in the GUI at once, blitting is far smoother and faster from the user's perspective than incrementally shuffling things around or hiding/showing elements as you go -- and is much more certain to feel the same across platforms and various computer speeds and userland loads (some Wx backends give a lot of flicker or intermediate display weirdness otherwise).
The do_show/1 function usually looks something like
do_show(#s{frame = Frame}) ->
ok = wxFrame:raise(Frame),
wxFrame:requestUserAttention(Frame).
(I have been meaning to write a basic "here is one way to structure a multi-window wxErlang application" tutorial/example but just haven't gotten around to it, so a lot of details are missing here but you'll stumble on them on your own after writing a couple of programs.)

Can I get a calibrated image and skeleton from the Official Kinect SDK at the same time?

Basically, I just want those three things.
Color, Depth, and Skeleton. But I also want the depth and color lined up.
I know that in the official examples, there's GreenScreen.cpp, which is an example of depth/color cut-outs, but no skeleton. There's also SkeletonBasics which has a skeleton, but no image.
I've tried learning from both of them and implementing them together, but I never get a callback for when the skeleton is ready (this: m_hNextSkeletonEvent).
SkeletonBasics.cpp uses this:
hEvents[0] = m_hNextSkeletonEvent;
// Check to see if we have either a message (by passing in QS_ALLEVENTS)
// Or a Kinect event (hEvents)
// Update() will check for Kinect events individually, in case more than one are signalled
DWORD dwEvent = MsgWaitForMultipleObjects(eventCount, hEvents, FALSE, INFINITE, QS_ALLINPUT);
// Check if this is an event we're waiting on and not a timeout or message
if (WAIT_OBJECT_0 == dwEvent)
{
Update();
}
And GreenScreen.cpp uses this:
hEvents[0] = m_hNextDepthFrameEvent;
hEvents[1] = m_hNextColorFrameEvent;
// Check to see if we have either a message (by passing in QS_ALLINPUT)
// Or a Kinect event (hEvents)
// Update() will check for Kinect events individually, in case more than one are signalled
DWORD dwEvent = MsgWaitForMultipleObjects(eventCount, hEvents, FALSE, INFINITE, QS_ALLINPUT);
// Check if this is an event we're waiting on and not a timeout or message
if (WAIT_OBJECT_0 == dwEvent || WAIT_OBJECT_0 + 1 == dwEvent)
{
Update();
}
But, like I said, combining them yields no
if ( WAIT_OBJECT_0 == WaitForSingleObject(m_hNextSkeletonEvent, 0) )
happening. (The KinectBridgeWithOpenCVBasics-D2D also does Skeleton, Color, and Depth, but still is unaligned (like this example I found in a search).
Do you know why the event is not firing? Or perhaps do you know of an example somewhere that has all of these abilities? I've searched high and low, and I've tried tons of different things messing with these examples, but I just cant seem to get it.
Thanks for your help.
EDIT:
At the end of KinectBridgeWithOpenCVBasics, I'm left with a m_colorMat and an m_depthMat. Even if at that point I could align the depth to color, I think that would work out just fine.

Simulating mouse events in Actionscript 3

Given stage coordinates (x,y), I want to make my flash app behave just as if the user clicked at position (x,y). That is, something like
function simulateClick(x:Number, y:Number):void{
var e:MouseEvent = new MouseEvent(MouseEvent.CLICK, true, false, x, y)
stage.dispatchEvent(e);
}
I've found a bunch of pages talking about this kind of thing, and they all give solutions similar to the above. However, this isn't equivalent to the user clicking at (x,y). There are two problems:
The first is that e.stageX and e.stageY are both 0. I can't set them directly. The documentation says they are calculated when e.localX and e.localY are set, but this isn't happening when I set e.localX before dispatchEvent, nor in the event listener.
I could rewrite all of my event listeners with something like this:
var p:Point = e.target.localToGlobal(new Point(e.localX, e.localY));
Is this the only option?
The second problem is that my event listeners are registered with children of stage, not stage itself. So I need to find out what target to call dispatchEvent on. Clearly Flash is capable of determining what the target should be, ie which object owns the topmost pixel visible at position (x,y), because it does so when the user actually clicks. Is there an easy way to get at this information, or should I just write my own recursive function to do the same thing? I'm using DisplayObjectContainer.getObjectsUnderPoint at the moment, but it's not quite right.
I'm writing in FlashDevelop, if that makes any difference.
e.stageX/Y is populated correctly for me... also getObjectsUnderPoint() seems to work fine. I'm assuming that the x/y values passed to simulateClick are global coordinates?
edit: as pointed out in the comments, the mouse event must be dispatched on InteractiveObject instances... modified the code accordingly.
import flash.display.Bitmap;
import flash.display.BitmapData;
import flash.display.DisplayObject;
import flash.display.InteractiveObject;
import flash.display.Sprite;
import flash.events.MouseEvent;
import flash.geom.Point;
public function simulateClick(x:Number, y:Number):void
{
var objects:Array = stage.getObjectsUnderPoint(new Point(x, y));
var target:DisplayObject;
while(target = objects.pop())
{
if(target is InteractiveObject)
{
break;
}
}
if(target !== null)
{
var local:Point = target.globalToLocal(new Point(x, y));
var e:MouseEvent = new MouseEvent(MouseEvent.CLICK, true, false, local.x, local.y);
target.dispatchEvent(e);
}
}
public function addedToStage():void
{
var parent:Sprite = new Sprite();
stage.addChild(parent);
var child:Sprite = new Sprite();
child.name = 'child 1';
child.graphics.beginFill(0xff0000, 1);
child.graphics.drawRect(0, 0, 200, 200);
child.graphics.endFill();
var child2:Sprite = new Sprite();
child2.name = 'child 2';
child2.graphics.beginFill(0xff00ff, 1);
child2.graphics.drawRect(0, 0, 100, 100);
child2.graphics.endFill();
child2.x = 150;
child2.y = 150;
var bmpData:BitmapData = new BitmapData(80, 80, false, 0x00ff00);
var bmp:Bitmap = new Bitmap(bmpData);
bmp.name = 'bitmap';
child2.addChild(bmp);
parent.addChild(child);
parent.addChild(child2);
child2.addEventListener(MouseEvent.CLICK, function(e:MouseEvent):void
{
trace('target: ' + e.target.name);
trace('localX: ' + e.localX);
trace('localY: ' + e.localY);
trace('stageX: ' + e.stageX);
trace('stageY: ' + e.stageY);
});
simulateClick(190, 190);
}
Output:
target: child 2
localX: 40
localY: 40
stageX: 190
stageY: 190
For question 1: After you create the MouseEvent (assigning it a local x,y) you should be able to directly reference e.stageX and set it to what you want prior to dispatching the event. It's just a property of the MouseEvent instance.
For #2, currentTarget is always the thing that is topmost under the mouse, while target is the thing that is dispatching the event -- assuming the event is genuinely being dispatched by mouse interaction. In your case, you can set the target to be whatever object you have dispatching the event, and set the currentTarget arbitrarily. The question really is whether this is the most efficient way to deal with what's under the mouse right now; and the answer is, probably not. You'd be a lot better off using a MOUSE_OVER event to keep tabs on what the mouse is over right now, store that as a variable you can use when you want to call this, and don't try to iterate the whole display chain all the time (because Flash natively does that much faster than you can do it in a loop). If you put a mouseOver on the stage, and just check the currentTarget, you'll be getting whatever the topmost item is under the mouse on every frame where it changes.
You should be aware that (to prevent some obvious nasty scripts), certain actions cannot be triggered by mouse events that are generated dynamically by actionscript. These include opening a file reference and going fullscreen.
I have faced this issue too, gave me a bit of a headache.
In my situation I was creating the event, performing a bit of complex computations, but I couldn't retrieve global coordinates even though I had already set local coordinates.
Actually the solution was quite obvious in my case...
Global coordinates are populated only AFTER the event is dispatched, otherwise how can the event know how to translate local to global?
This is another pitfall, on top of not checking for the object used to dispatch event being an InteractiveObject.
I post this because someone else may face this issue due to both pitfalls. A quick answer easy to read.

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