I'm using a camera and barcode markers. In order for my cannon to shoot I need to spawn a sphere when a clicked. I tried to get the marker position by using .getAttribute('position') but I'm getting disappointing results e.g. null and [object, object]. Is there a real way to to access the coordinates of a marker in AFrame? So far it creates a sphere but right in the camera because its unable to find the location of the marker.
Javascript
var sceneEl = document.querySelector('a-scene'); //select scene
var markerEl = document.querySelector('#cannonMarker');
// trigger event when button is pressed.
document.addEventListener("click", function (e) {
var pos = markerEl.getAttribute('position');
var Sphere = document.createElement('a-sphere');
Sphere.setAttribute('dynamic-body', {
shape: 'sphere',
mass: 4
});
Sphere.setAttribute('position', pos);
sceneEl.appendChild(Sphere);
console.log('Sphere coordinates:' + pos);
});
Provided the marker is being recognized and the references are correct
markerEl.getAttribute('position')
should return the current marker position.
If your script is in the <head> element, the marker may not yet exist when the code is executed.
It's a good idea to throw your code into an a-frame component:
HTML:
<a-scene ball-spawner></a-scene>
js:
AFRAME.registerComponent('ball-spawner', {
init: function() {
// your code here - the scene should be ready
}
})
I've made a slight modification to your code (working glitch here):
var sceneEl = document.querySelector('a-scene'); //select scene
var markerEl = document.querySelector('a-marker');
// trigger event when button is pressed.
sceneEl.addEventListener("click", function (e) {
if (markerEl.object3D.visible === false) {
return;
}
var pos = markerEl.getAttribute('position');
var Sphere = document.createElement('a-sphere');
Sphere.setAttribute('radius', 0.5)
Sphere.setAttribute('dynamic-body', {
shape: 'sphere',
mass: 4
});
Sphere.setAttribute('position', pos);
sceneEl.appendChild(Sphere);
});
}
When the marker gets out of vision, it's position is 'last remembered'. So it's the same place on the screen. That's why there's a return if the marker element is not visible.
It seems to be working as you want since the ball is falling out of a transparent box on the marker (the box is a nice way to be sure the marker is recognized):
Related
I'm trying to replicate a potter's wheel effect, where a user can click on a piece of the wheel, hold down the mouse, and a circle will be created with respect to the center of the wheel.
Like in this persons demo: https://balazsdavid987.github.io/Pottery-Wheel/
But what's happening for me can be seen here:
http://p2-paperjs-dpayne5-dpayne589733.codeanyapp.com:3000/coloring/
The relevant pieces of code are the following:
var tool = new paper.Tool();
//array to hold all curves drawn from mousedrags
var allPaths = [];
var currPath;
var rotationPath;
//wheel center point, #center of canvas
var wheelCenter = new paper.Point(350,350);
//create the potters wheel
var wheel = new paper.Path.Circle({
center: wheelCenter,
radius: 300,
strokeColor: 'black',
strokeWidth: 5
});
//hold down to create a continous curve with respect to wheelCenter
tool.onMouseDown = function(event) {
currPath = new paper.Path();
currPath.strokeColor = cp.history[cp.history.length-1];
currPath.strokeWidth = 10;
currPath.add(event.point);
}
//creates a curve from the last position to the new position of mouse
tool.onMouseDrag = function(event) {
currPath.add(currPath.rotate(4, wheelCenter));
}
//add the curve to allPaths, which then gets animated in onFrame
tool.onMouseUp = function(event) {
allPaths.push(currPath);
}
paper.view.onFrame = function(event) {
for (var i = 0; i < allPaths.length; i++) {
allPaths[i].rotate(4, wheelCenter);
}
//testPath.rotate(3, wheelCenter);
}
paper.view.draw();
I'm not understanding why the mouseDrag would make a circle way father out from where my mouse has clicked, and I've been stuck on this for awhile.
Any help would be greatly appreciated, thanks!
Apart from your technical difficulty with the onMouseDrag method, I think that you should change your approach to the problem.
The thing is that if you rely on mouse drag event (which is only triggered when the mouse move), you won't be able to paint on the wheel by keeping your mouse static (as shown in your reference demo).
So you would better keep track of the mouse position (by listening to a mouse move event), and draw on each frame, adding the last mouse position to the current path (only when drawing of course).
Better than a thousand words, here is a sketch demonstrating how this can be achieved.
// Create the wheel.
const wheel = new Path.Circle({
center: view.center,
radius: 300,
strokeColor: 'black',
strokeWidth: 3
});
// Create a group that will contain all the user drawn path.
// This will allow us to more easily rotate them together.
const paths = new Group();
// Init state variables.
let currentPath;
let drawing = false;
let lastMousePosition;
// On mouse down...
function onMouseDown(event) {
// ...start a new path.
currentPath = new Path({
segments: [event.point],
strokeColor: 'red',
strokeWidth: 2
});
// Add it to the paths group.
paths.addChild(currentPath);
// Mark state as drawing.
drawing = true;
}
// On mouse move...
function onMouseMove(event) {
// ...keep track of the mouse position, this will be used to add points to
// the current path on each frame.
lastMousePosition = event.point;
}
// On mouse up...
function onMouseUp(event) {
// ...improve performances by simplifying the path.
currentPath.simplify();
// Mark state as not drawing.
drawing = false;
}
// On each frame...
function onFrame(event) {
// ...rotate paths around the wheel center.
paths.rotate(4, wheel.position);
// If we are currently drawing...
if (drawing) {
// ...add the last mouse position to the current path.
currentPath.add(lastMousePosition);
}
}
I'm pretty much new to canvas. What I'm trying to make is that I can write text in canvas using input and can be able to resize it by dragging it's corners. Also I should be able to drag text position within the canvas.
Following is the screen shot of what I want!
Canvas is raster, not vector. By simply drawing and resizing text you would expect it to get blurry or pixelated. And redrawing the whole canvas each time user moves the cursor while resizing will not result in the best performance. Consider using svg instead. In case you do need canvas and don't want to implement all the functions yourself, you can use the paperjs library.
http://paperjs.org/reference/pointtext/
As #hirasawa-yui mentioned, you can use Paper.js to greatly facilitate the implementation of what you want in a canvas.
Here is a simplified sketch showing a possible implementation of dragging/resizing interactions.
// create item
var item = new PointText({
content: 'Custom text content',
point: view.center,
justification: 'center',
fontSize: 30,
selected: true
});
// init variables so they can be shared by event handlers
var resizeVector;
var moving;
// on mouse down...
function onMouseDown(event) {
// ...do a hit test on item bounds with a small tolerance for better UX
var cornerHit = item.hitTest(event.point, {
bounds: true,
tolerance: 5
});
// if a hit is detected on one of the corners...
if (cornerHit && ['top-left', 'top-right', 'bottom-left', 'bottom-right'].indexOf(cornerHit.name) >= 0) {
// ...store current vector from item center to point
resizeVector = event.point - item.bounds.center;
// ...else if hit is detected inside item...
} else if (item.hitTest(event.point, { fill: true })) {
// ...store moving state
moving = true;
}
}
// on mouse drag...
function onMouseDrag(event) {
// ...if a corner was previously hit...
if (resizeVector) {
// ...calculate new vector from item center to point
var newVector = event.point - item.bounds.center;
// scale item so current mouse position is corner position
item.scale(newVector / resizeVector);
// store vector for next event
resizeVector = newVector;
// ...if item fill was previously hit...
} else {
// ...move item
item.position += event.delta;
}
}
// on mouse up...
function onMouseUp(event) {
// ... reset state
resizeVector = null;
moving = null;
}
// draw instructions
new PointText({
content: 'Drag rectangle to move, drag corners to resize.',
point: view.center + [0, -50],
justification: 'center'
});
I'm trying to develop a function with leaflet which make user be able to draw a circle by pressing ctrl & dragging mouse, as the following
let mouseDownPos = null
let mouseUpPos = null
L.Map.CircleSelector = L.Map.Drag.extend({
_onMouseDown: function(e) {
if (!e.ctrlKey)
return
let map = this._map
map.dragging.disable()
mouseDownPos = map.containerPointToLatLng(this._point)
},
_onMouseUp: function(e) {
if (!e.ctrlKey) {
this._map.dragging.enable()
return
}
let map = this._map
mouseUpPos = map.containerPointToLatLng(this._point)
let radius = map.distance(mouseDownPos, mouseUpPos)
L.circle(mouseDownPos, {radius: radius}).addTo(map)
map.dragging.enable()
}
})
L.Map.mergeOptions({circleSelector: true})
L.Map.addInitHook('addHandler', 'circleSelector', L.Map.CircleSelector)
When I press ctrl & drag mouse on the map, it still does not work.
I've tried to print text to console at the beginning in _onMouseDown(), it shows nothing.
It seems that the event doesn't trigger.
What should I need to modify? Thank you.
Finally I extend leaflet.draw to approach my goal.
Refer to the source code of L.Draw.Circle, I extend my selector from L.Draw.Circle. The mainly modified part is in _onMouseUp, as the following
L.Map.CircleSelector = L.Draw.SimpleShape.extend({
_onMouseUp: function (e) {
// TODO
// 1. Get the circle center & radius
// 2. Calculate distances between center & markers
// 3. If the distance in step 2 <= radius, it is in the circle
// 4. Anything you'd like to do......
}
})
The rest code of the event can be referred to L.Draw.Circle, e.g., addHooks, _onMouseMove......
I'm having problems, trying to display the mouse position x/y when they click on an image, im using one of the click on and image example that phaser provides.
here is the code
var game = new Phaser.Game(800, 500, Phaser.AUTO, 'phaser-example', { preload: preload, create: create });
var text;
var counter = 0;
function preload () {
// You can fill the preloader with as many assets as your game requires
// Here we are loading an image. The first parameter is the unique
// string by which we'll identify the image later in our code.
// The second parameter is the URL of the image (relative)
game.load.image('Happy-face', 'happy.png');
}
function create() {
// This creates a simple sprite that is using our loaded image and
// displays it on-screen and assign it to a variable
var image = game.add.sprite(game.world.centerX, game.world.centerY, 'Happy-face');
// Moves the image anchor to the middle, so it centers inside the game properly
image.anchor.set(0.5);
// Enables all kind of input actions on this image (click, etc)
image.inputEnabled = true;
this.position = new Phaser.Point();
text = game.add.text(250, 16, '', { fill: '#ffffff' });
image.events.onInputDown.add(listener, this);
}
function listener () {
counter++;
text.text = "Position x/y " + counter + "!";
}
if you want x and y position o f input
game.input.x;
game.input.y;
if you want for mouse specifically
game.input.mousePointer.x;
game.input.mousePointer.y;
the listener function will be like
function listener () {
counter++;
text.text = game.input.mousePointer.x +"/"+game.input.mousePointer.y + counter + "!";
}
Just to add that the listener function will be sent 2 parameters: sprite and pointer. So you can do:
function listener (sprite, pointer) {
var x = pointer.x;
var y = pointer.y;
...
}
This will be the most accurate method to use as it accounts for multi-touch devices, where-as accessing input.x/y directly doesn't, it only contains the most recent touch event coordinates (which in a mouse only environment is fine, but not anywhere else).
Using the Google Earth plugin, I want to be able to allow the user to select placemarks on the ground while the camera is moving, but am not sure how this is possible. It seems that when you call setAbstractView(), even with the flyToSpeed set to SPEED_TELEPORT, the Google Earth plugin ignores any mouse down events except for those to the GEGlobe.
Here's the code, altered slightly (from http://code.google.com/apis/ajax/playground/#draggable_placemark) to illustrate my issue:
var ge;
var placemark;
var dragInfo = null;
var la;
var lat = 37;
var lon = -122;
google.load("earth", "1");
function init() {
google.earth.createInstance('map3d', initCallback, failureCallback);
}
function tick() {
la.set(lat, lon,
0, // altitude
ge.ALTITUDE_RELATIVE_TO_GROUND,
0, // heading
0, // straight-down tilt
5000 // range (inverse of zoom)
);
ge.getView().setAbstractView(la);
lon = lon + 0.00000001;
}
function initCallback(instance) {
ge = instance;
ge.getWindow().setVisibility(true);
// add a navigation control
ge.getNavigationControl().setVisibility(ge.VISIBILITY_AUTO);
// add some layers
ge.getLayerRoot().enableLayerById(ge.LAYER_BORDERS, true);
ge.getLayerRoot().enableLayerById(ge.LAYER_ROADS, true);
// create the placemark
placemark = ge.createPlacemark('');
var point = ge.createPoint('');
point.setLatitude(lat);
point.setLongitude(lon);
placemark.setGeometry(point);
// add the placemark to the earth DOM
ge.getFeatures().appendChild(placemark);
// look at the placemark we created
la = ge.createLookAt('');
placemark.setName('Drag Me!');
ge.getOptions().setFlyToSpeed(ge.SPEED_TELEPORT);
tick();
// Comment this next line out and the drag works as expected.
google.earth.addEventListener(ge, "frameend", tick);
// listen for mousedown on the window (look specifically for point placemarks)
google.earth.addEventListener(ge.getWindow(), 'mousedown', function(event) {
console.log("target type = " + event.getTarget().getType());
if (event.getTarget().getType() == 'KmlPlacemark' &&
event.getTarget().getGeometry().getType() == 'KmlPoint') {
//event.preventDefault();
var placemark = event.getTarget();
dragInfo = {
placemark: event.getTarget(),
dragged: false
};
}
});
// listen for mousemove on the globe
google.earth.addEventListener(ge.getGlobe(), 'mousemove', function(event) {
if (dragInfo) {
event.preventDefault();
var point = dragInfo.placemark.getGeometry();
point.setLatitude(event.getLatitude());
point.setLongitude(event.getLongitude());
dragInfo.dragged = true;
}
});
// listen for mouseup on the window
google.earth.addEventListener(ge.getWindow(), 'mouseup', function(event) {
if (dragInfo) {
if (dragInfo.dragged) {
// if the placemark was dragged, prevent balloons from popping up
event.preventDefault();
}
dragInfo = null;
}
});
document.getElementById('installed-plugin-version').innerHTML =
ge.getPluginVersion().toString();
}
function failureCallback(errorCode) {
}
If you comment out line 56, where tick() is called at each frameend, everything works as in the unaltered code: you can successfully drag the place mark. But when line 56 is in, you can't. So the problem is really with setAbstractView keeping mousedown events from propagating to either the globe or whatever placemark or feature was being clicked.
Any ideas? Is there a workaround for this?
The issue isn't caused by the setAbstractView method, it is caused because of the repeated calls to the tick method via framend.
To explain, you have set up the tick method as an event handler for the frameend event.
Then the tick method updates the view immediately, triggering the frameend event, ad infinitum ...
This pattern causes an issue with the browser message loop, in effect it is blocking the other drag events. Think of it like a very tight loop that is causing a deadlock. To work it you can use setTimeout with a value of 0 to execute the code. This way the animation won't be processed until all other pending drag messages are processed.
The key part is a the modification to your tick() method.
function tick() {
// prevent deadlock
setTimeout(function () {
la.set(lat, lon, 0, ge.ALTITUDE_RELATIVE_TO_GROUND, 0, 0, 5000);
ge.getView().setAbstractView(la);
lon += 0.00001;
}, 0);
};
Here, I made a fully working example for you http://jsfiddle.net/fraser/JFLaT/
I tested it and it is working in Chrome, IE, Firefox on Windows 8 and Chrome, Safari, Firefox on OSX.