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• I am new to game development, what do I need to know? [closed]

  - by farmdve

  I am unsure if this question is a duplicate, I hope it isn't. Are there any resources on the terminology when doing game development? Because, even if you tell me to learn some graphics API, how would I understand the things it does, if I am not well into the terminology(voxel,mesh,polygon,shading). What about the math that is involved in the game(geometry) or the concept of the gravity,collision detection in the game and their respective maths? I am very bad at math, never was good, because I have ADHD, but I won't give up just yet. I look at a game, and I see "textures", but how am I walking on them, how do they take substance so I don't fall off of them? And depth? This is what I need information about, not just a link to a library like SDL(which I have compiled under MinGW and MinGW-W64) and tell me to learn it and the cliché answer "start simple/small". I hope the question(s) are not too vague.

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• Calculating a circle or sphere along a vector

  - by Sparky

  Updated this post and the one at Math SE (http://math.stackexchange.com/questions/127866/calculating-a-circle-or-sphere-along-a-vector), hope this makes more sense. I previously posted a question (about half an hour ago) involving computations along line segments, but the question and discussion were really off track and not what I was trying to get at. I am trying to work with an FPS engine I am attempting to build in Java. The problem I am encountering is with hitboxing. I am trying to calculate whether or not a "shot" is valid. I am working with several approaches and any insight would be helpful. I am not a native speaker of English nor skilled in Math so please bear with me. Player position is at P0 = (x0,y0,z0), Enemy is at P1 = (x1,y1,z1). I can of course compute the distance between them easily. The target needs a "hitbox" object, which is basically a square/rectangle/mesh either in front of, in, or behind them. Here are the solutions I am considering: I have ruled this out...doesn't seem practical. [Place a "hitbox" a small distance in front of the target. Then I would be able to find the distance between the player and the hitbox, and the hitbox and the target. It is my understanding that you can compute a circle with this information, and I could simply consider any shot within that circle a "hit". However this seems not to be an optimal solution, because it requires you to perform a lot of calculations and is not fully accurate.] Input, please! Place the hitbox "in" the player. This seems like the better solution. In this case what I need is a way to calculate a circle along the vector, at whatever position I wish (in this case, the distance between the two objects). Then I can pick some radius that encompasses the whole player, and count anything within this area a "hit". I am open to your suggestions. I'm trying to do this on paper and have no familiarity with game engines. If any software folk out there think I'm doing this the hard way, I'm open to help! Also - Anyone with JOGL/LWJGL experience, please chime in. Is this making sense?

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• Circular movement - eliminating speed ups near Y = 0

  - by Fibericon

  I have a basic algorithm to rotate an enemy around a 200 unit radius circle with center 0. This is how I'm achieving that: if (position.Y <= 0 && position.X > -200) { position.X -= 2; position.Y = 0 - (float)Math.Sqrt((200 * 200) - (position.X * position.X)); } else { position.X += 2; position.Y = (float)Math.Sqrt((200 * 200) - (position.X * position.X)); } It does work, and I've ensured that at no point does either X or Y equal NaN. However, when Y approaches 0, it seems to go significantly faster. This surprises me, because the Y values are locked to the X, which is being incremented by a steady amount. What can I do to smooth the speed?

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• Actionscript - Dropping Multiple Objects Using an Array?

  - by Eratosthenes

  I'm trying to get these fireBalls to drop more often, im not sure if im using Math.random correctly also, for some reason I'm getting a null reference because I think the fireBalls array waits for one to leave the stage before dropping another one? this is the relevant code: var sun:Sun=new Sun var fireBalls:Array=new Array() var left:Boolean; function onEnterFrame(event:Event){ if (left) { sun.x = sun.x - 15; }else{ sun.x = sun.x + 15; } if (fireBalls.length>0&&fireBalls[0].y>stage.stageHeight){ // Fireballs exit stage removeChild(fireBalls[0]); fireBalls.shift(); } for (var j:int=0; j<fireBalls.length; j++){ fireBalls[j].y=fireBalls[j].y+15; if (fireBalls[j].y>stage.stageHeight-fireBall.width/2){ } } if (Math.random()<.2){ // Fireballs shooting from Sun var fireBall:FireBall=new FireBall; fireBall.x=sun.x; addChild(fireBall); fireBalls.push(fireBall); } }

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• SlimDX: Lightning problem with Direct3D9

  - by Spi1988

  I am creating a simple application to get familiar with SlimDX library. I found some code written in MDX and I'm trying to convert it to run on SlimDX. I am having some problems with the light because everything is being shown as black. The code is: public partial class DirectTest : Form { private Device device= null; private float angle = 0.0f; Light light = new Light(); public DirectTest() { InitializeComponent(); this.Size = new Size(800, 600); this.SetStyle(ControlStyles.AllPaintingInWmPaint | ControlStyles.Opaque, true); } /// <summary> /// We will initialize our graphics device here /// </summary> public void InitializeGraphics() { PresentParameters pres_params = new PresentParameters() { Windowed = true, SwapEffect = SwapEffect.Discard }; device = new Device(new Direct3D(), 0, DeviceType.Hardware, this.Handle, CreateFlags.SoftwareVertexProcessing, pres_params); } private void SetupCamera() { device.SetRenderState(RenderState.CullMode, Cull.None); device.SetTransform(TransformState.World, Matrix.RotationAxis(new Vector3(angle / ((float)Math.PI * 2.0f), angle / ((float)Math.PI * 4.0f), angle / ((float)Math.PI * 6.0f)), angle / (float)Math.PI)); angle += 0.1f; device.SetTransform(TransformState.Projection, Matrix.PerspectiveFovLH((float)Math.PI / 4, this.Width / this.Height, 1.0f, 100.0f)); device.SetTransform(TransformState.View, Matrix.LookAtLH(new Vector3(0, 0, 5.0f), new Vector3(), new Vector3(0, 1, 0))); device.SetRenderState(RenderState.Lighting, false); } protected override void OnPaint(System.Windows.Forms.PaintEventArgs e) { device.Clear(ClearFlags.Target | ClearFlags.ZBuffer, Color.CornflowerBlue, 1.0f, 0); SetupCamera(); CustomVertex.PositionColored[] verts = new CustomVertex.PositionColored[3]; verts[0].Position = new Vector3(0.0f, 1.0f, 1.0f); verts[0].Normal = new Vector3(0.0f, 0.0f, -1.0f); verts[0].Color = System.Drawing.Color.White.ToArgb(); verts[1].Position = new Vector3(-1.0f, -1.0f, 1.0f); verts[1].Normal = new Vector3(0.0f, 0.0f, -1.0f); verts[1].Color = System.Drawing.Color.White.ToArgb(); verts[2].Position = new Vector3(1.0f, -1.0f, 1.0f); verts[2].Normal = new Vector3(0.0f, 0.0f, -1.0f); verts[2].Color = System.Drawing.Color.White.ToArgb(); light.Type = LightType.Point; light.Position = new Vector3(); light.Diffuse = System.Drawing.Color.White; light.Attenuation0 = 0.2f; light.Range = 10000.0f; device.SetLight(0, light); device.EnableLight(0, true); device.BeginScene(); device.VertexFormat = CustomVertex.PositionColored.format; device.DrawUserPrimitives<CustomVertex.PositionColored>(PrimitiveType.TriangleList, 1, verts); device.EndScene(); device.Present(); this.Invalidate(); } } } The Vertex Format that I am using is the following [StructLayout(LayoutKind.Sequential)] public struct PositionNormalColored { public Vector3 Position; public int Color; public Vector3 Normal; public static readonly VertexFormat format = VertexFormat.Diffuse | VertexFormat.Position | VertexFormat.Normal; } Any suggestions on what the problem might be? Thanks in Advance

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• Common Mercator Projection formulas for Google Maps not working correctly

  - by Tom Halladay

  I am building a Tile Overlay server for Google maps in C#, and have found a few different code examples for calculating Y from Latitude. After getting them to work in general, I started to notice certain cases where the overlays were not lining up properly. To test this, I made a test harness to compare Google Map's Mercator LatToY conversion against the formulas I found online. As you can see below, they do not match in certain cases. Case #1 Zoomed Out: The problem is most evident when zoomed out. Up close, the problem is barely visible. Case #2 Point Proximity to Top & Bottom of viewing bounds: The problem is worse in the middle of the viewing bounds, and gets better towards the edges. This behavior can negate the behavior of Case #1 The Test: I created a google maps page to display red lines using the Google Map API's built in Mercator conversion, and overlay this with an image using the reference code for doing Mercator conversion. These conversions are represented as black lines. Compare the difference. The Results: Check out the top-most and bottom-most lines: The problem gets visually larger but numerically smaller as you zoom in: And it all but disappears at closer zoom levels, regardless of screen orientation. The Code: Google Maps Client Side Code: var lat = 0; for (lat = -80; lat <= 80; lat += 5) { map.addOverlay(new GPolyline([new GLatLng(lat, -180), new GLatLng(lat, 0)], "#FF0033", 2)); map.addOverlay(new GPolyline([new GLatLng(lat, 0), new GLatLng(lat, 180)], "#FF0033", 2)); } Server Side Code: Tile Cutter : http://mapki.com/wiki/Tile_Cutter OpenStreetMap Wiki : http://wiki.openstreetmap.org/wiki/Mercator protected override void ImageOverlay_ComposeImage(ref Bitmap ZipCodeBitMap) { Graphics LinesGraphic = Graphics.FromImage(ZipCodeBitMap); Int32 MapWidth = Convert.ToInt32(Math.Pow(2, zoom) * 255); Point Offset = Cartographer.Mercator2.toZoomedPixelCoords(North, West, zoom); TrimPoint(ref Offset, MapWidth); for (Double lat = -80; lat <= 80; lat += 5) { Point StartPoint = Cartographer.Mercator2.toZoomedPixelCoords(lat, -179, zoom); Point EndPoint = Cartographer.Mercator2.toZoomedPixelCoords(lat, -1, zoom); TrimPoint(ref StartPoint, MapWidth); TrimPoint(ref EndPoint, MapWidth); StartPoint.X = StartPoint.X - Offset.X; EndPoint.X = EndPoint.X - Offset.X; StartPoint.Y = StartPoint.Y - Offset.Y; EndPoint.Y = EndPoint.Y - Offset.Y; LinesGraphic.DrawLine(new Pen(Color.Black, 2), StartPoint.X, StartPoint.Y, EndPoint.X, EndPoint.Y); LinesGraphic.DrawString( lat.ToString(), new Font("Verdana", 10), new SolidBrush(Color.Black), new Point( Convert.ToInt32((width / 3.0) * 2.0), StartPoint.Y)); } } protected void TrimPoint(ref Point point, Int32 MapWidth) { point.X = Math.Max(point.X, 0); point.X = Math.Min(point.X, MapWidth - 1); point.Y = Math.Max(point.Y, 0); point.Y = Math.Min(point.Y, MapWidth - 1); } So, Anyone ever experienced this? Dare I ask, resolved this? Or simply have a better C# implementation of Mercator Project coordinate conversion? Thanks!

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• I'm trying to make lots of the same object appear randomly on the screen subject to conditions and k

  - by Katsideswide

  Hi! A good friend recommended this site to me, it looks really useful! I'm a bit of a shameless noob at actionscript and after 3 days of tutorials and advice I've hit a brick wall. I've managed to get a sensor attached to an arduino talking to flash using something called AS3glue. it works, when i set up a trace("leaf") for the contition that the sensor reads 0, i get a printout of the word "leaf". however i want the program to make a graphic appear on the screen when this condition is met, not just trace something. I'm trying to get the program to generate a library object called "Enemy" on the screen at a random position each time the conditions are met. It's called enemy because I was following a game tutorial...actually it's a drawing of a leaf. Here's the bit of the code which is causing me problems: var army:Array; var enemy:Enemy; function AvoiderGame() { army = new Array(); var newEnemy = new Enemy( 100, 100 ); army.push( newEnemy ); addChild( newEnemy ); } function timerEvent(event:Event):void { if (a.getAnalogData(0) ==0 && a.getAnalogData(0) != this.lastposition){ trace("leaf"); var randomX:Number = (Math.random() * 200) + 100; var randomY:Number = (Math.random() * 150) + 50; var newEnemy = new Enemy( randomX, randomY); army.push( newEnemy ); addChild( newEnemy ); } else if (a.getAnalogData(0) == 0) { //don't trace anything } else { //don't trace anything } this.lastposition = a.getAnalogData(0); //afterwards, set the position to be the new lastposition and repeat. } I've imported "import flash.display.MovieClip;" and the code for the Enemy class looks like this: package { import flash.display.MovieClip; public class Enemy extends MovieClip { public function Enemy( startX:Number, startY:Number ) { x = startX; y = startY; } } } Here's my error. I've tried googling, it seems like a pretty general error: TypeError: Error #1009: Cannot access a property or method of a null object reference. at as3glue_program_fla::MainTimeline/timerEvent() at flash.utils::Timer/_timerDispatch() at flash.utils::Timer/tick() I've made sure that the "Enemy" object is exported for AS3. I'm going for something like this when it's programmed in AS2: leafCounter = 0; //set the counter to 0 counter.swapDepths(1000); //puts the counter on top of pretty much anything, unless you make more than 1000 leaves! counter.textbox.text = 0; //shows "0" in the text box in the "counter" movie clip this.onMouseDown = function() { //triggers when the mouse is clicked this.attachMovie("Leaf","Leaf"+leafCounter,leafCounter,{_x:Math.random()*Stage.width,_y:Math.random()*Stage.height,_rotation:Math.random()*360}); //adds a leaf to rthe stage with a random position and random rotation leafCounter++; //adds 1 to the leaf counter counter.textbox.text = leafCounter; //shows that number in the text box } I'm sure it must be a simple error, I can get the logic working when it just traces something on the screen but i can't get it to generate an "enemy" Any help or hints would be really useful! I know this is a bit of a ham-fisted job of altering existing code.

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• Path to background in servlet

  - by kapil chhattani

  //the below line is the element of my HTML form which renders the image sent by the servlet written further below. <img style="margin-left:91px; margin-top:-6px;" class="image" src="http://www.abcd.com/captchaServlet"> I generate a captcha code using the following code in java. public class captchaServlet extends HttpServlet { protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { int width = 150; int height = 50; int charsToPrint = 6; String elegibleChars = "ABCDEFGHJKLMPQRSTUVWXYabcdefhjkmnpqrstuvwxy1234567890"; char[] chars = elegibleChars.toCharArray(); StringBuffer finalString = new StringBuffer(); for ( int i = 0; i < charsToPrint; i++ ) { double randomValue = Math.random(); int randomIndex = (int) Math.round(randomValue * (chars.length - 1)); char characterToShow = chars[randomIndex]; finalString.append(characterToShow); } System.out.println(finalString); BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics2D g2d = bufferedImage.createGraphics(); Font font = new Font("Georgia", Font.BOLD, 18); g2d.setFont(font); RenderingHints rh = new RenderingHints( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); rh.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY); g2d.setRenderingHints(rh); GradientPaint gp = new GradientPaint(0, 0, Color.BLUE, 0, height/2, Color.black, true); g2d.setPaint(gp); g2d.fillRect(0, 0, width, height); g2d.setColor(new Color(255, 255, 0)); Random r = new Random(); int index = Math.abs(r.nextInt()) % 5; char[] data=new String(finalString).toCharArray(); String captcha = String.copyValueOf(data); int x = 0; int y = 0; for (int i=0; i<data.length; i++) { x += 10 + (Math.abs(r.nextInt()) % 15); y = 20 + Math.abs(r.nextInt()) % 20; g2d.drawChars(data, i, 1, x, y); } g2d.dispose(); response.setContentType("image/png"); OutputStream os = response.getOutputStream(); ImageIO.write(bufferedImage, "png", os); os.close(); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } } But in the above code background is also generated using the setPaint menthod I am guessing. I want the background to be some image from my local machine whoz URL i should be able to mention like URL url=this.getClass().getResource("Desktop/images.jpg"); BufferedImage bufferedImage = ImageIO.read(url); I am just writing the above two lines for making the reader understand better what the issue is. Dont want to use the exact same commands. All I want is the the background of the captcha code generated should be an image of my choice.

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• MSAcpi_ThermalZoneTemperature class not showing actual temperature

  - by jchoudhury

  i want to fetch CPU Performance data in real time including temperature. i used the following code to get CPU Temperature: try { ManagementObjectSearcher searcher = new ManagementObjectSearcher("root\\WMI", "SELECT * FROM MSAcpi_ThermalZoneTemperature"); foreach (ManagementObject queryObj in searcher.Get()) { double temp = Convert.ToDouble(queryObj["CurrentTemperature"].ToString()); double temp_critical = Convert.ToDouble(queryObj["CriticalTripPoint"].ToString()); double temp_cel = (temp/10 - 273.15); double temp_critical_cel = temp_critical / 10 - 273.15; lblCurrentTemp.Text = temp_cel.ToString(); lblCriticalTemp.Text = temp_critical_cel.ToString(); } } catch (ManagementException e) { MessageBox.Show("An error occurred while querying for WMI data: " + e.Message); } but this code shows the temperature that is not the correct temperature. It ususally shows 49.5-50.5 degrees centigrade. But I used "OpenHardwareMonitor" that report CPU temperature over 71 degree centigrade and changing fractions along with time fractions. is there anything I am missing in the code? I used the above code in timer_click event for every 500ms interval to refresh the temperature reading but it's always showing the same temperature from the beginning of execution. That implies if you run this application and if it shows 49 degree then after 1 hour session, it'll constantly show 49 degree. Where is the problem? please help. Thanks in advance.

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• c# find nearest match to array of doubles

  - by Scott

  Given the code below, how do I compare a List of objects's values with a test value? I'm building a geolocation application. I'll be passing in longitude and latitude and would like to have the service answer back with the location closest to those values. I started down the path of converting to a string, and formatting the values down to two decimal places, but that seemed a bit too ghetto, and I'm looking for a more elegant solution. Any help would be great. Thanks, Scott public class Location : IEnumerable { public string label { get; set; } public double lat { get; set; } public double lon { get; set; } //Implement IEnumerable public IEnumerator GetEnumerator() { return (IEnumerator)this; } } [HandleError] public class HomeController : Controller { private List<Location> myList = new List<Location> { new Location { label="Atlanta Midtown", lon=33.657674, lat=-84.423130}, new Location { label="Atlanta Airport", lon=33.794151, lat=-84.387228}, new Location { label="Stamford, CT", lon=41.053758, lat=-73.530979}, ... } public static int Main(String[] args) { string inLat = "-80.987654"; double dblInLat = double.Parse(inLat); // here's where I would like to find the closest location to the inLat // once I figure out this, I'll implement the Longitude, and I'll be set }

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• Wpf binding to a function

  - by carlopenid

  I've a created a simple scrollviewer (pnlDayScroller) and want to have a separate horizontal scrollbar (associated scroller) to do the horizontal scrolling. All works with the below code accept I need to bind the visibility of the associated scroller. I can't simply bind this to the visibility property of the horizontal template part of the scroll viewer as I've set this to be always hidden. The only way I can think to do this is to bind the visibility of the associated scroller to a function such that If associatedScroller.scrollableWidth > 0 then associatedScroller.visibility = visibility.visible else associatedScroller.visibility = visibility.collapsed end if Is this possible to do and if so how do I do it? Private Sub pnlDayScroller_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles pnlDayScroller.Loaded Dim binViewport, binMax, binMin, binSChange, binLChange As Binding Dim horizontalScrollBar As Primitives.ScrollBar = CType(pnlDayScroller.Template.FindName("PART_HorizontalScrollBar", pnlDayScroller), Primitives.ScrollBar) binViewport = New Binding("ViewportSize") binViewport.Mode = BindingMode.OneWay binViewport.Source = horizontalScrollBar associatedScroller.SetBinding(Primitives.ScrollBar.ViewportSizeProperty, binViewport) binMax = New Binding("Maximum") binMax.Mode = BindingMode.OneWay binMax.Source = horizontalScrollBar associatedScroller.SetBinding(Primitives.ScrollBar.MaximumProperty, binMax) binMin = New Binding("Minimum") binMin.Mode = BindingMode.OneWay binMin.Source = horizontalScrollBar associatedScroller.SetBinding(Primitives.ScrollBar.MinimumProperty, binMin) binSChange = New Binding("SmallChange") binSChange.Mode = BindingMode.OneWay binSChange.Source = horizontalScrollBar associatedScroller.SetBinding(Primitives.ScrollBar.SmallChangeProperty, binSChange) binLChange = New Binding("LargeChange") binLChange.Mode = BindingMode.OneWay binLChange.Source = horizontalScrollBar associatedScroller.SetBinding(Primitives.ScrollBar.LargeChangeProperty, binLChange) End Sub Private Sub associatedScroller_Scroll(ByVal sender As System.Object, ByVal e As System.Windows.RoutedPropertyChangedEventArgs(Of Double)) Handles associatedScroller.ValueChanged pnlDayScroller.ScrollToHorizontalOffset(e.NewValue) end sub FOLLOW UP (thanks to JustABill) : I've add this code into the pnlDayScroller sub above (I've discovered scrollableWidth is a property of scrollviewer not scrollbar, but the maximum property gives a result I can use instead) binVisibility = New Binding("Maximum") binVisibility.Mode = BindingMode.OneWay binVisibility.Source = horizontalScrollBar binVisibility.Converter = New ScrollableConverter associatedScroller.SetBinding(Primitives.ScrollBar.VisibilityProperty, binVisibility) and I've created this class Public Class ScrollableConverter Implements IValueConverter Public Function Convert(ByVal value As Object, ByVal targetType As Type, ByVal parameter As Object, ByVal culture As System.Globalization.CultureInfo) As Object Implements IValueConverter.Convert Dim dblMaximum As Double If targetType IsNot GetType(Visibility) Then Throw New InvalidOperationException("The target must be a visibility") Else dblMaximum = CType(value, Double) Debug.WriteLine("Value of double is " & dblMaximum) If dblMaximum > 0 Then Return Visibility.Visible Else Return Visibility.Collapsed End If End If End Function Public Function ConvertBack(ByVal value As Object, ByVal targetType As Type, ByVal parameter As Object, ByVal culture As System.Globalization.CultureInfo) As Object Implements IValueConverter.ConvertBack Throw New NotSupportedException() End Function End Class And the problem is resolved.

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• Linq-To-Objects group by

  - by Oskar Kjellin

  Hey, I'm building a software for timereporting I have a Dictionary<string, Dictionary<string, double>>. The key in the main dictionary is a users name and their value is a dictionary of . I have a function GetDepartment(string UserName) which returns a string with the users department. What I want is to crate a new dictionary, of the same type, that has the department as the main key and in the subdictionary a where hours is the total for that department. I have been trying to do this with linq but did not succeed. Would be very glad for some help here! EDIT: This code does exactly what I want. But I want it in LINQ Dictionary<string, Dictionary<string, double>> temphours = new Dictionary<string, Dictionary<string, double>>(); ; foreach (var user in hours) { string department = GetDepartment(user.Key); if (!temphours.ContainsKey(department)) { temphours.Add(department, new Dictionary<string, double>()); } foreach (var customerReport in user.Value) { if (!temphours[department].ContainsKey(customerReport.Key)) { temphours[department].Add(customerReport.Key, 0); } temphours[department][customerReport.Key] += customerReport.Value; } }

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• the problem of "cvEigenVV"

  - by gg-anny

  Hi!When I compile the program,VC2005 always tell :"error C2198: 'cvEigenVV' : too few arguments for call". Part of the code below: void draw_oxfd_feature( IplImage* img, struct feature* feat, CvScalar color ) { double m[4] = { feat-a, feat-b, feat-b, feat-c }; double v[4] = { 0 }; double e[2] = { 0 }; CvMat M; CvMat V; CvMat E; double alpha, l1, l2; /* compute axes and orientation of ellipse surrounding affine region */ cvInitMatHeader( &M, 2, 2, CV_64FC1, m, CV_AUTOSTEP ); cvInitMatHeader( &V, 2, 2, CV_64FC1, v, CV_AUTOSTEP ); cvInitMatHeader( &E, 2, 1, CV_64FC1, e, CV_AUTOSTEP ); cvEigenVV( &M, &V, &E, DBL_EPSILON ); l1 = 1 / sqrt( e[1] ); l2 = 1 / sqrt( e[0] ); alpha = -atan2( v[1], v[0] ); alpha *= 180 / CV_PI; cvEllipse( img, cvPoint( feat-x, feat-y ), cvSize( l2, l1 ), alpha, 0, 360, CV_RGB(0,0,0), 3, 8, 0 ); cvEllipse( img, cvPoint( feat-x, feat-y ), cvSize( l2, l1 ), alpha, 0, 360, color, 1, 8, 0 ); cvLine( img, cvPoint( feat-x+2, feat-y ), cvPoint( feat-x-2, feat-y ), color, 1, 8, 0 ); cvLine( img, cvPoint( feat-x, feat-y+2 ), cvPoint( feat-x, feat-y-2 ), color, 1, 8, 0 ); // cvCircle(img,cvPoint(cvRound( feat-x ),cvRound( feat-y )),2, color, CV_FILLED, 8, 0); cvCircle(img,cvPoint( cvRound( feat-x ), cvRound( feat-y )), 2,CV_RGB(0,255,0), CV_FILLED, 8, 0 ); } How to solve the problem?Thank you!

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• Efficient Multiple Linear Regression in C# / .Net

  - by mrnye

  Does anyone know of an efficient way to do multiple linear regression in C#, where the number of simultaneous equations may be in the 1000's (with 3 or 4 different inputs). After reading this article on multiple linear regression I tried implementing it with a matrix equation: Matrix y = new Matrix( new double[,]{{745}, {895}, {442}, {440}, {1598}}); Matrix x = new Matrix( new double[,]{{1, 36, 66}, {1, 37, 68}, {1, 47, 64}, {1, 32, 53}, {1, 1, 101}}); Matrix b = (x.Transpose() * x).Inverse() * x.Transpose() * y; for (int i = 0; i < b.Rows; i++) { Trace.WriteLine("INFO: " + b[i, 0].ToDouble()); } However it does not scale well to the scale of 1000's of equations due to the matrix inversion operation. I can call the R language and use that, however I was hoping there would be a pure .Net solution which will scale to these large sets. Any suggestions? EDIT #1: I have settled using R for the time being. By using statconn (downloaded here) I have found it to be both fast & relatively easy to use this method. I.e. here is a small code snippet, it really isn't much code at all to use the R statconn library (note: this is not all the code!). _StatConn.EvaluateNoReturn(string.Format("output <- lm({0})", equation)); object intercept = _StatConn.Evaluate("coefficients(output)['(Intercept)']"); parameters[0] = (double)intercept; for (int i = 0; i < xColCount; i++) { object parameter = _StatConn.Evaluate(string.Format("coefficients(output)['x{0}']", i)); parameters[i + 1] = (double)parameter; }

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• Resizing and saving an image in WinMobile and .NET CF throws OutOfMemoryException

  - by devguy

  I have a WinMobile app which allows the user the snap a photo with the camera, and then use for for various things. The photo can be snapped at 1600x1200, 800x600 or 640x480, but it must always be resized to 400px for the longest size (the other is proportional of course). Here's the code: private void LoadImage(string path) { Image tmpPhoto = new Bitmap(path); // calculate new bitmap size... double width = ... double height = ... // draw new bitmap Image photo = new Bitmap(width, height, System.Drawing.Imaging.PixelFormat.Format24bppRgb); using (Graphics g = Graphics.FromImage(photo)) { g.FillRectangle(new SolidBrush(Color.White), new Rectangle(0, 0, photo.Width, photo.Height)); int srcX = (int)((double)(tmpPhoto.Width - width) / 2d); int srcY = (int)((double)(tmpPhoto.Height - height) / 2d); g.DrawImage(tmpPhoto, new Rectangle(0, 0, photo.Width, photo.Height), new Rectangle(srcX, srcY, photo.Width, photo.Height), GraphicsUnit.Pixel); } tmpPhoto.Dispose(); // save new image and dispose photo.Save(Path.Combine(config.TempPath, config.TempPhotoFileName), System.Drawing.Imaging.ImageFormat.Jpeg); photo.Dispose(); } Now the problem is that the app breaks in the photo.Save call, with an OutOfMemoryException. And I don't know why, since I dispose the tempPhoto (with the original photo from the camera) as soon as I can, and I also dispose the Graphics obj. Why does this happen? It seems impossible to me that one can't take a photo with the camera and resize/save it without making it crash :( Should I restor t C++ for such a simple thing? Thanks.

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• Linq-To-Entities group by

  - by Oskar Kjellin

  Hey, I'm building a software for timereporting I have a Dictionary<string, Dictionary<string, double>>. The key in the main dictionary is a users name and their value is a dictionary of . I have a function GetDepartment(string UserName) which returns a string with the users department. What I want is to crate a new dictionary, of the same type, that has the department as the main key and in the subdictionary a where hours is the total for that department. I have been trying to do this with linq but did not succeed. Would be very glad for some help here! EDIT: This code does exactly what I want. But I want it in LINQ Dictionary<string, Dictionary<string, double>> temphours = new Dictionary<string, Dictionary<string, double>>(); ; foreach (var user in hours) { string department = GetDepartment(user.Key); if (!temphours.ContainsKey(department)) { temphours.Add(department, new Dictionary<string, double>()); } foreach (var customerReport in user.Value) { if (!temphours[department].ContainsKey(customerReport.Key)) { temphours[department].Add(customerReport.Key, 0); } temphours[department][customerReport.Key] += customerReport.Value; } }

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• Resize transparent images using C#

  - by MartinHN

  Does anyone have the secret formula to resizing transparent images (mainly GIFs) without ANY quality loss - what so ever? I've tried a bunch of stuff, the closest I get is not good enough. Take a look at my main image: http://www.thewallcompany.dk/test/main.gif And then the scaled image: http://www.thewallcompany.dk/test/ScaledImage.gif //Internal resize for indexed colored images void IndexedRezise(int xSize, int ySize) { BitmapData sourceData; BitmapData targetData; AdjustSizes(ref xSize, ref ySize); scaledBitmap = new Bitmap(xSize, ySize, bitmap.PixelFormat); scaledBitmap.Palette = bitmap.Palette; sourceData = bitmap.LockBits(new Rectangle(0, 0, bitmap.Width, bitmap.Height), ImageLockMode.ReadOnly, bitmap.PixelFormat); try { targetData = scaledBitmap.LockBits(new Rectangle(0, 0, xSize, ySize), ImageLockMode.WriteOnly, scaledBitmap.PixelFormat); try { xFactor = (Double)bitmap.Width / (Double)scaledBitmap.Width; yFactor = (Double)bitmap.Height / (Double)scaledBitmap.Height; sourceStride = sourceData.Stride; sourceScan0 = sourceData.Scan0; int targetStride = targetData.Stride; System.IntPtr targetScan0 = targetData.Scan0; unsafe { byte* p = (byte*)(void*)targetScan0; int nOffset = targetStride - scaledBitmap.Width; int nWidth = scaledBitmap.Width; for (int y = 0; y < scaledBitmap.Height; ++y) { for (int x = 0; x < nWidth; ++x) { p[0] = GetSourceByteAt(x, y); ++p; } p += nOffset; } } } finally { scaledBitmap.UnlockBits(targetData); } } finally { bitmap.UnlockBits(sourceData); } } I'm using the above code, to do the indexed resizing. Does anyone have improvement ideas?

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• JavaScript and JQuery - Encoding HTML

  - by user70192

  Hello, I have a web page that has a textarea defined on it like so: <textarea id="myTextArea" rows="6" cols="75"></textarea> There is a chance that a user may enter single and double quotes in this field. For instance, I have been testing with the following string: Just testin' using single and double "quotes". I'm hoping the end of this task is comin'. Additionally, the user may enter HTML code, which I would prefer to prevent. Regardless, I am passing the contents of this textarea onto web service. I must encode the contents of the textarea in JavaScript before I can send it on. Currently, I'm trying the following: var contents $('<div/>').text($("#myTextArea).val()).html(); alert(contents); I was expecting contents to display Just testin&#39; using single and double &#34;quotes&#34;. I&#39;m hoping the end of this task is comin&#39;. Instead, the original string is printed out. Beyond just double-and-single quotes, there are a variety of entities to consider. Because of this, I was assuming there would be a way to encode HTML before passing it on. Can someone please tell me how to do this? Thank you,

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• Strange C++ performance difference?

  - by STingRaySC

  I just stumbled upon a change that seems to have counterintuitive performance ramifications. Can anyone provide a possible explanation for this behavior? Original code: for (int i = 0; i < ct; ++i) { // do some stuff... int iFreq = getFreq(i); double dFreq = iFreq; if (iFreq != 0) { // do some stuff with iFreq... // do some calculations with dFreq... } } While cleaning up this code during a "performance pass," I decided to move the definition of dFreq inside the if block, as it was only used inside the if. There are several calculations involving dFreq so I didn't eliminate it entirely as it does save the cost of multiple run-time conversions from int to double. I expected no performance difference, or if any at all, a negligible improvement. However, the perfomance decreased by nearly 10%. I have measured this many times, and this is indeed the only change I've made. The code snippet shown above executes inside a couple other loops. I get very consistent timings across runs and can definitely confirm that the change I'm describing decreases performance by ~10%. I would expect performance to increase because the int to double conversion would only occur when iFreq != 0. Chnaged code: for (int i = 0; i < ct; ++i) { // do some stuff... int iFreq = getFreq(i); if (iFreq != 0) { // do some stuff with iFreq... double dFreq = iFreq; // do some stuff with dFreq... } } Can anyone explain this? I am using VC++ 9.0 with /O2. I just want to understand what I'm not accounting for here.

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• VBA Public Function to Excel

  - by Sugih

  Dear sir , I have create below function Option Explicit Public Function fyi(x As Double, f As String) As String Application.Volatile Dim data As Double Dim post(5) post(1) = "Ribu " post(2) = "Juta " post(3) = "Milyar " post(4) = "Trilyun " post(5) = "Ribu Trilyun " Dim part As String Dim text As String Dim cond As Boolean Dim i As Integer If (x < 0) Then fyi = " " Exit Function End If If (x = 0) Then fyi = "Nol" Exit Function End If If (x < 2000) Then cond = True End If text = " " If (x >= 1E+15) Then fyi = "Nilai Terlalu Besar" Exit Function End If For i = 4 To 1 Step -1 data = Int(x / (10 ^ (3 * i))) If (data 0) Then part = fyis(data, cond) text = text & part & post(i) End If x = x - data * (10 ^ (3 * i)) Next text = text & fyis(x, False) fyi = text & f End Function Function fyis(ByVal y As Double, ByVal conds As Boolean) As String Dim datas As Double Dim posts(2) posts(1) = "Puluh" posts(2) = "Ratus" Dim parts As String Dim texts As String 'Dim conds As Boolean Dim j As Integer Dim value(9) value(1) = "Se" value(2) = "Dua " value(3) = "Tiga " value(4) = "Empat " value(5) = "Lima " value(6) = "Enam " value(7) = "Tujuh " value(8) = "Delapan " value(9) = "Sembilan " texts = " " For j = 2 To 1 Step -1 datas = Int(y / 10 ^ j) If (datas 0) Then parts = value(datas) If (j = 1 And datas = 1) Then y = y - datas * 10 ^ j If (y = 1) Then posts(j) = "belas" Else value(y) = "Se" End If texts = texts & value(y) & posts(j) fyis = texts Exit Function Else texts = texts & parts & posts(j) End If End If y = y - datas * 10 ^ j Next If (conds = False) Then value(1) = "Satu " End If texts = texts & value(y) fyis = texts End Function but when I return to Excel and type '=fyi(500,"USD") it return to #name? please do me favor to inform me how to solve Rgds, Sugih

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• Correct escaping of delimited identifers in SQL Server without using QUOTENAME

  - by Ross Bradbury

  Is there anything else that the code must do to sanitize identifiers (table, view, column) other than to wrap them in double quotation marks and "double up" and double quotation marks present in the identifier name? References would be appreciated. I have inherited a code base that has a custom object-relational mapping (ORM) system. SQL cannot be written in the application but the ORM must still eventually generate the SQL to send to the SQL Server. All identifiers are quoted with double quotation marks. string QuoteName(string identifier) { return "\" + identifier.Replace("\"", "\"\"") + "\""; } If I were building this dynamic SQL in SQL, I would use the built-in SQL Server QUOTENAME function: declare @identifier nvarchar(128); set @identifier = N'Client"; DROP TABLE [dbo].Client; --'; declare @delimitedIdentifier nvarchar(258); set @delimitedIdentifier = QUOTENAME(@identifier, '"'); print @delimitedIdentifier; -- "Client""; DROP TABLE [dbo].Client; --" I have not found any definitive documentation about how to escape quoted identifiers in SQL Server. I have found Delimited Identifiers (Database Engine) and I also saw this stackoverflow question about sanitizing. If it were to have to call the QUOTENAME function just to quote the identifiers that is a lot of traffic to SQL Server that should not be needed. The ORM seems to be pretty well thought out with regards to SQL Injection. It is in C# and predates the nHibernate port and Entity Framework etc. All user input is sent using ADO.NET SqlParameter objects, it is just the identifier names that I am concerned about in this question. This needs to work on SQL Server 2005 and 2008.

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• Reading CSV files in numpy where delimiter is ","

  - by monch1962

  Hello all, I've got a CSV file with a format that looks like this: "FieldName1", "FieldName2", "FieldName3", "FieldName4" "04/13/2010 14:45:07.008", "7.59484916392", "10", "6.552373" "04/13/2010 14:45:22.010", "6.55478493312", "9", "3.5378543" ... Note that there are double quote characters at the start and end of each line in the CSV file, and the "," string is used to delimit fields within each line. When I try to read this into numpy via: import numpy as np data = np.genfromtxt(csvfile, dtype=None, delimiter=',', names=True) all the data gets read in as string values, surrounded by double-quote characters. Not unreasonable, but not much use to me as I then have to go back and convert every column to its correct type When I use delimiter='","' instead, everything works as I'd like, except for the 1st and last fields. As the start of line and end of line characters are a single double-quote character, this isn't seen as a valid delimiter for the 1st and last fields, so they get read in as e.g. "04/13/2010 14:45:07.008 and 6.552373" - note the leading and trailing double-quote characters respectively. Because of these redundant characters, numpy assumes the 1st and last fields are both String types; I don't want that to be the case Is there a way of instructing numpy to read in files formatted in this fashion as I'd like, without having to go back and "fix" the structure of the numpy array after the initial read?

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• database design to speed up hibernate querying of large dataset

  - by paddydub

  I currently have the below tables representing a bus network mapped in hibernate, accessed from a Spring MVC based bus route planner I'm trying to make my route planner application perform faster, I load all the above tables into Lists to perform the route planner logic. I would appreciate if anyone has any ideas of how to speed my performace Or any suggestions of another method to approach this problem of handling a large set of data Coordinate Connections Table (INT,INT,INT)( Containing 50,000 Coordinate Connections) ID, FROMCOORDID, TOCOORDID 1 1 2 2 1 17 3 1 63 4 1 64 5 1 65 6 1 95 Coordinate Table (INT,DECIMAL, DECIMAL) (Containing 4700 Coordinates) ID , LAT, LNG 0 59.352669 -7.264341 1 59.352669 -7.264341 2 59.350012 -7.260653 3 59.337585 -7.189798 4 59.339221 -7.193582 5 59.341408 -7.205888 Bus Stop Table (INT, INT, INT)(Containing 15000 Stops) StopID RouteID COORDINATEID 1000100001 100 17 1000100002 100 18 1000100003 100 19 1000100004 100 20 1000100005 100 21 1000100006 100 22 1000100007 100 23 This is how long it takes to load all the data from each table: stop.findAll = 148ms, stops.size: 15670 Hibernate: select coordinate0_.COORDINATEID as COORDINA1_2_, coordinate0_.LAT as LAT2_, coordinate0_.LNG as LNG2_ from COORDINATES coordinate0_ coord.findAll = 51ms , coordinates.size: 4704 Hibernate: select coordconne0_.COORDCONNECTIONID as COORDCON1_3_, coordconne0_.DISTANCE as DISTANCE3_, coordconne0_.FROMCOORDID as FROMCOOR3_3_, coordconne0_.TOCOORDID as TOCOORDID3_ from COORDCONNECTIONS coordconne0_ coordinateConnectionDao.findAll = 238ms ; coordConnectioninates.size:48132 Hibernate Annotations @Entity @Table(name = "STOPS") public class Stop implements Serializable { @Id @GeneratedValue @Column(name = "COORDINATEID") private Integer CoordinateID; @Column(name = "LAT") private double latitude; @Column(name = "LNG") private double longitude; } @Table(name = "COORDINATES") public class Coordinate { @Id @GeneratedValue @Column(name = "COORDINATEID") private Integer CoordinateID; @Column(name = "LAT") private double latitude; @Column(name = "LNG") private double longitude; } @Entity @Table(name = "COORDCONNECTIONS") public class CoordConnection { @Id @GeneratedValue @Column(name = "COORDCONNECTIONID") private Integer CoordinateID; /** * From Coordinate_id value */ @Column(name = "FROMCOORDID", nullable = false) private int fromCoordID; /** * To Coordinate_id value */ @Column(name = "TOCOORDID", nullable = false) private int toCoordID; //private Coordinate toCoordID; }

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• How to convert CMYK to RGB programmatically in indesign.

  - by BBDeveloper

  Hi, I have a CMYK colorspace in indesign, i want to convert that as RGB color space, I got some codes, but I am getting incorrect data. Some of the codes which I tried are given below double cyan = 35.0; double magenta = 29.0; double yellow = 0.0; double black = 16.0; cyan = Math.min(255, cyan + black); //black is from K magenta = Math.min(255, magenta + black); yellow = Math.min(255, yellow + black); l_res[0] = 255 - cyan; l_res[1] = 255 - magenta; l_res[2] = 255 - yellow; @Override public float[] toRGB(float[] p_colorvalue) { float[] l_res = {0,0,0}; if (p_colorvalue.length >= 4) { float l_black = (float)1.0 - p_colorvalue[3]; l_res[0] = l_black * ((float)1.0 - p_colorvalue[0]); l_res[1] = l_black * ((float)1.0 - p_colorvalue[1]); l_res[2] = l_black * ((float)1.0 - p_colorvalue[2]); } return (l_res); } The values are C=35, M = 29, Y = 0, K = 16 in CMYK color space and the correct RGB values are R = 142, G = 148, B = 186. In adobe indesign, using swatches we can change the mode to CMYK or to RGB. But I want to do that programmatically, Can I get any algorithm to convert CMYK to RGB which will give the correct RGB values. And one more question, if the alpha value for RGB is 1 then what will be the alpha value for CMYK? Can anyone help me to solve these issues... Thanks in advance.

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• create TableModel and populate jTable dynamically

  - by Julia

  Hi all! I want to store the results of reading lucene index into jTable, so that I can make it sortable by different columns. From index I am reading terms with different measures of their frequencies. Table columns are these : [string term][int absFrequency][int docFrequency][double invFrequency] So i in AbstractTableModel I can define column names, but i dont know how to get the Object[][]data with results from the following method: public static void FrequencyMap(Directory indexDir) throws Exception { List<Object>redoviLista = new ArrayList<Object>(); //final Map<String,TermRow> map = new TreeMap<String,TermRow>(); List<String>termList = new ArrayList<String>(); IndexReader iReader = IndexReader.open(indexDir); FilterIndexReader fReader = new FilterIndexReader(iReader); int numOfDocs = fReader.numDocs(); TermEnum terms = fReader.terms(); while (terms.next()){ Term term = terms.term(); String termText = term.text(); termList.add(termText); //Calculating the frequencies int df = iReader.docFreq(term); double idf = 0.0F; idf = Math.log10((double) numOfDocs / df); double tfidf = (df*idf); //Here comes important part Object oneTableRow[] = {termText, df, idf, tfidf}; redoviLista.add(jedanRed); // So i thaught to store them into list, and then later to copy into table, but didnt manage } iReader.close(); // So I need something like this, and i Neeed this array to be stored out of this method Object[][]data = new Object[redoviLista.size()][]; for (int i = 0; i < data.length; i++) { data[i][0] = redoviLista.get(i); } So I am kindda stuck here to proceed to implement AbstractTableModel and populate and display this table .... :/ Please help!

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