Creating Grid in as3 - performance

I am trying to make to grid to squares using as3.
I am using nested for loops to create the grid.
import flash.display.Shape;
import flash.display.MovieClip;
var n=10;
var myClip = new MovieClip;
stage.addChild(myClip);
for (var i = 0; i < n * 10; i += 10) {
for (var j = 0; j < n * 10; j += 10) {
var _shape = new Shape;
myClip.addChild(_shape);
_shape.graphics.lineStyle(1);
_shape.graphics.beginFill(0xcccccc);
_shape.graphics.drawRect(i, j, 10, 10);
_shape.graphics.endFill();
}
}
I am applying Zooming and Panning Gestures on myClip. For this Grid size everything works fine. As soon as I increase the value of n, it starts lagging
My game requires a bigger grid. Please help

I'll show some ideas as code, my AS3 is a bit rusty but perhaps it helps.
You can reduce the number of Shape instances or draw the vector based grid graphic to a Bitmap. Since you are zooming and panning it you'll want to smooth it. Depending on performance and how much you zoom you also may want to draw the bitmap at a higher resolution than initially used. See comments in the below.
import flash.display.Shape;
import flash.display.MovieClip;
var n=10;
// do you actually need dynamic binding or a timeline in this?
// if not (also if you don't know what it means) do use the Sprite class instead
var myClip = new MovieClip;
stage.addChild(myClip);
// if you don't need individual shapes move this out of the for loop
// your logic with all of the shapes having the same origin suggests this might be so
var _shape = new Shape;
myClip.addChild(_shape);
for (var i = 0; i < n * 10; i += 10) {
for (var j = 0; j < n * 10; j += 10) {
_shape.graphics.lineStyle(1);
_shape.graphics.beginFill(0xcccccc);
_shape.graphics.drawRect(i, j, 10, 10);
_shape.graphics.endFill();
}
}
// then we can draw the grid to a bitmap
// since you are scaling it I'm drawing it a 300% resolution
var _bmd:BitmapData = new BitmapData(_shape.width*3, _shape.height*3, true, 0);
var _bit:Bitmap = new Bitmap(_bmd);
myClip.addChild(_bit);
_shape.width*=3;
_shape.height*=3;
_bmd.draw(stage);
_bit.smoothing = true;
_bit.width/=3;
_bit.height/=3;
// and remove the vector shape so it won't be rendered
myClip.removeChild(_shape);
// if need be it can be redrawn later

Related

Kinect Depth Histogram in Processing

I'm trying to create a histogram displaying the distances scanned by a Kinect vs. their occurrences. I've adapted the Histogram example code to create a depth histogram, but it's currently displaying the depth at each pixel (from left to right) multiple times across the depth image width.
What I'm looking to do is reorder the depth information so that it ranges from the lowest value (that isn't 0) to the highest on the x axis, and shows their occurrences on the y. I'm using Processing, so I'm unsure if this is the right site to be posting on, but I've tried on the posting forum and not gotten any help. If anyone can show me where I'm going wrong, that'd be awesome. My current code is below, and a screenshot of my current output can be found here
import SimpleOpenNI.*;
SimpleOpenNI kinect;
void setup() {
size(1200, 580);
kinect = new SimpleOpenNI(this);
kinect.enableDepth();
}
void draw () {
kinect.update();
PImage depthImage = kinect.depthImage();
image (depthImage, 11, 0);
int[] depthValues = kinect.depthMap();
int[] hist = new int[716800];
for (int x = 11; x < depthImage.width; x++) {
for (int y = 0; y < depthImage.height; y++) {
int i = x + y * 640;
hist[i] = depthValues[i];
}
}
int histMax = max(hist);
stroke(20);
for (int i = 0; i < depthImage.width; i += 2) {
int which = int(map(i, 0, depthImage.width, 0, histMax));
int y = int(map(hist[which], 0, histMax, depthImage.height, 0));
line(i, depthImage.height, i, y);
}
}
I think you're asking two questions here.
How to get the histogram to go from 0-N:
Use Processing's sort() function to sort the array.
hist = sort(hist); // sorts your array numerically
How to get the histogram to fill the screen:
I'm not entirely sure why it's drawing twice, but I think you can clean up your code quite a bit.
// how far apart are the bars - set based on screen dimensions
int barSpacing = width / hist.length;
for (int i=0; i<hist.length; i++) {
// get value and map into usable range (note 10 not 0 for min)
int h = int(map(hist[i], 0,histMax, 10,height));
// set x position onscreen
int x = i * barSpacing;
// draw the bar
line(x,height, x,height-h);
}

Three.js set the center of a Object3D based on internal meshes

I have a mesh set that is in a Object3D when i get the vertices they are not centered on the object. so i need to compute the center of the object3D then move the meshes to align them to the center. I have tried computing the boundingboxes of each Mesh then max - min /2; this does not work. Any help here would be fantastic. I have tried the Object3D.setFromObject(); this only return infinity.
To center an Object3D, depending on its children, you have to iterate through them, as far as I know. The code would look like the following:
// myObject3D is your Object3D
var children = myObject3D.children,
completeBoundingBox = new THREE.Box3(); // create a new box which will contain the entire values
for(var i = 0, j = children.length; i < j; i++){ // iterate through the children
children[i].geometry.computeBoundingBox(); // compute the bounding box of the the meshes geometry
var box = children[i].geometry.boundingBox.clone(); // clone the calculated bounding box, because we have to translate it
box.translate(children[i].position); // translate the geometries bounding box by the meshes position
completeBoundingBox.addPoint(box.max).addPoint(box.min); // add the max and min values to your completeBoundingBox
}
var objectCenter = completeBoundingBox.center()
console.log('This is the center of your Object3D:', objectCenter );
// You want the center of you bounding box to be at 0|0|0
myObject3D.position.x -= objectCenter.x;
myObject3D.position.y -= objectCenter.y;
myObject3D.position.z -= objectCenter.z;
Hope I understood your problem right!
center = function(obj) {
var children = obj.children,
completeBoundingBox = new THREE.Box3();
for(var i = 0, j = children.length; i < j; i++) {
children[i].geometry.computeBoundingBox();
var box = children[i].geometry.boundingBox.clone();
box.translate(children[i].position);
completeBoundingBox.set(box.max, box.min);
}
var objectCenter = completeBoundingBox.center()
console.log('This is the center of your Object3D:', objectCenter );
obj.position.x -= objectCenter.x;
obj.position.y -= objectCenter.y;
obj.position.z -= objectCenter.z;
}

Zooming into canvas via js causes content to be lost?

http://deepschool.kd.io/Pages/Experiments/draw.htm
This is a Image editor I am working on, But it has a bug. Let's say you have created an image a 15x Zoom, when you change the zoom, the image is lost. Why is this? and what is the Remedy?
HTML:
Zoom:
<input type="number" id="zoom" min="1" max="50" onchange="zoomy()">
JS:
var zoomy = function() {
var zoomamount = zoom.value
var canvassize = zoomamount * 16
c.width = canvassize
c.height = canvassize
};
Thanks In Advance
If you want to zoom into canvas, it means you have to redraw it with zoom.
So instead of drawing pixels on click right onto canvas, which is made of pure pixels... You need to first create some representation of your grid of pixels.
var gridOfPixels = [];
Let's say you are ok with static size for now. Make it 8x8 pixels. At start you want to initialize your array:
for (var i=0; i < 8*8; i++) gridOfPixels[i] = 0;
So the grid canvas is ready, now we need to draw it.
function renderGrid() {
for (var y=0; y < 8; y++)
for (var x=0; x < 8; x++)
renderPixel( x, y, gridOfPixels[x+y*8] );
}
You already know how to renderPixel - calculate the rectangle position (posX = x*pixWidth, posY*pixHeight), where pixWidth is canvasWidth/8, etc.. Now you draw all your pixels, using the third parameter for the color.
To finish, you have to connect onclick to put a pixel on grid, and then call renderGrid so the user sees the change.
$('#my-canvas').click(function(e) {
var x = ...;
var y = ...; // calculate the position of pixels from mouse position inside canvas
// dont forget to check that x,y are in the 0-7 range
// dont forget to convert x,y to whole number using parseInt()
gridOfPixels[x+y*8] = 1;
renderGrid(); // update the grid canvas
});
Now, every time you resize the canvas or change some variables, the original canvas content will be saved in your grid, and you can renderGrid() any time you need to. You could even do it in realtime, animating the color of the pixels, etc..
Have fun. :)

How do I get a random number to stay fixed with slick?

I'm a beginner in Java as well as with the slick tools. I want to make a game that has different coloured cubes randomly placed within a certain area of the window.
I use two for-loops and call for a random number in render. I get the cubes placed exactly as I want, but the problems is that they flicker in all colours. I guess it has to do with how I call for a random number and that it gets updated with FPS?!
Please help me!!
public void render(GameContainer gc, StateBasedGame sdg, Graphics g) throws SlickException {
//set background
Image background = (new Image("res/background.png")).getScaledCopy(800, 500);
g.drawImage(background, 0, 0);
//set gamescape
blue = (new Image("res/blue.png")).getScaledCopy(20,20);
green = (new Image("res/green.png")).getScaledCopy(20,20);
red = (new Image("res/red.png")).getScaledCopy(20,20);
int xvalue = 300;
int yvalue = 400;
for (int a = 1; a < 20; a++) {
for (int i = 1; i < 10; i++) {
r = rand.nextInt(3);
if(r==0){g.drawImage(blue,xvalue,yvalue);}
else if(r==1){g.drawImage(red, xvalue, yvalue);}
else{g.drawImage(green, xvalue, yvalue);}
xvalue = xvalue+20;
}
yvalue = yvalue - 20;
xvalue = xvalue -180;
}
}
Your problem is that you generate a new random number each time you redraw the scene.
To resolve this, you may have to create an array in which you store the generated color of each cube. And each time you redraw your images, you just read each color value in the array.

Smart Centering and Scaling after Model Import in three.js

Is there a way to determine the size and position of a model and then auto-center and scale the model so that it is positioned at the origin and within the view of the camera? I find that when I import a Collada model from Sketchup, if the model was not centered at the origin in Sketchup, then it is not centered in three.js. While that makes sense, it would be nice to auto-center to origin after importing.
I've seen some discussion in the different file loaders about getting the bounds of the imported model, but I have been unable to find any references to how to do that.
The scaling issue is less important, but I feel like it relates to a bounds function, which is why I asked it too.
EDIT:
More info after playing around a bit and a few more google searches...
The code for my callback function on loading the collada file now looks like this:
loader.load(mURL, function colladaReady( collada ) {
dae = collada.scene;
skin = collada.skins[ 0 ];
dae.scale.x = dae.scale.y = dae.scale.z = 1;
dae.updateMatrix();
//set arbitrary min and max for comparison
var minX = 100000;
var minY = 100000;
var minZ = 100000;
var maxX = 0;
var maxY = 0;
var maxZ = 0;
var geometries = collada.dae.geometries;
for(var propName in geometries){
if(geometries.hasOwnProperty(propName) && geometries[propName].mesh){
dae.geometry = geometries[propName].mesh.geometry3js;
dae.geometry.computeBoundingBox();
bBox = dae.geometry.boundingBox;
if(bBox.min.x < minX) minX = bBox.min.x;
if(bBox.min.y < minY) minY = bBox.min.x;
if(bBox.min.z < minZ) minZ = bBox.min.z;
if(bBox.max.x > maxX) maxX = bBox.max.x;
if(bBox.max.y > maxY) maxY = bBox.max.x;
if(bBox.max.z > maxZ) maxZ = bBox.max.z;
}
}
//rest of function....
This is generating some interesting data about the model. I can get an overall extreme coordinate for the model, which I'm assuming (probably incorrectly) would be close to an overall bounding box for the model. But trying to do anything with those coordinates (like averaging and moving the model to the averages) generates inconsistent results.
Also, it seems inefficient to have to loop through every geometry for a model, is there a better way? If not, can this logic be applied to other loaders?
You can use THREE.Box3#setFromObject to get the bounding box of any Object3D, including an imported model, without having to loop through the geometries yourself. So you could do something like
var bBox = new THREE.Box3().setFromObject(collada.scene);
to get the extreme bounding box of the model; then you could use any of the techniques in the answers that gaitat linked in order to set the camera position correctly. For instance, you could follow this technique (How to Fit Camera to Object) and do something like:
var height = bBox.size().y;
var dist = height / (2 * Math.tan(camera.fov * Math.PI / 360));
var pos = collada.scene.position;
camera.position.set(pos.x, pos.y, dist * 1.1); // fudge factor so you can see the boundaries
camera.lookAt(pos);
Quick fiddle: http://jsfiddle.net/p19r9re2/ .
try geometry.center()
center: function () {
var offset = new Vector3();
return function center() {
this.computeBoundingBox();
this.boundingBox.getCenter( offset ).negate();
this.translate( offset.x, offset.y, offset.z );
return this;
};
}(),

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