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  • Name hiding from inherited classes

    - by Mercerbearman
    I have the following sample code and I wanted to know the correct way to get access to the Pass method in the CBar class. Currently I have found 3 ways to get access to this method and they are as follows: Casting the object, ((CBar *) &foo)-Pass(1, 2, 3); Using this syntax, foo.CBar::Pass(1,2,3); Use the "using" syntax in the CFoo class declaration, using CBar::Pass. The following is an example of a simple project to test this capability. Foo.h #include "bar.h" class CFoo : public CBar { private: double m_a; double m_b; public: CFoo(void); ~CFoo(void); void Pass(double a, double b); }; Foo.cpp #include "Foo.h" CFoo::CFoo(void) { m_a = 0.0; m_b = 0.0; } CFoo::~CFoo(void) { } void CFoo::Pass(double a, double b) { m_a = a; m_b = b; } Bar.h class CBar { int m_x; int m_y; int m_z; public: CBar(void); ~CBar(void); void Pass(int x, int y, int z); }; Bar.cpp #include "Bar.h" CBar::CBar(void) { m_x = 0; m_y = 0; m_z = 0; } CBar::~CBar(void) { } void CBar::Pass(int x, int y, int z) { m_x = x; m_y = y; m_z = z; } And my main class DoStuff.cpp #include "DoStuff.h" #include "Foo.h" CDoStuff::CDoStuff(void) { } CDoStuff::~CDoStuff(void) { } int main() { CFoo foo, foo1, foo2; //This only gets to the Pass method in Foo. foo.Pass(2.5, 3.5); //Gets access to Pass method in Bar. foo1.CBar::Pass(5,10,15); //Can also case and access by location for the same result?? ((CBar *) &foo2)->Pass(100,200,300); return 0; } Are each of these options viable? Are some preferred? Are there pitfalls with using any one of the methods listed? I am especially curious about the foo.CBar::Pass(1,2,3) syntax. Thanks, B

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  • Adding objects to the environment at timed intervals

    - by david
    I am using an ArrayList to handle objects and at each interval of 120 frames, I am adding a new object of the same type at a random location along the z-axis of 60. The problem is, it doesn't add just 1. It depends on how many are in the list. If I kill the Fox before the time interval when one is supposed to spawn comes, then no Fox will be spawned. If I don't kill any foxes, it grows exponentially. I only want one Fox to be added every 120 frames. This problem never happened before when I created new ones and added them to the environment. Any insights? Here is my code: /**** FOX CLASS ****/ import env3d.EnvObject; import java.util.ArrayList; public class Fox extends Creature { private int frame = 0; public Fox(double x, double y, double z) { super(x, y, z); // Must use the mutator as the fields have private access // in the parent class setTexture("models/fox/fox.png"); setModel("models/fox/fox.obj"); setScale(1.4); } public void move(ArrayList<Creature> creatures, ArrayList<Creature> dead_creatures, ArrayList<Creature> new_creatures) { frame++; setX(getX()-0.2); setRotateY(270); if (frame > 120) { Fox f = new Fox(60, 1, (int)(Math.random()*28)+1); new_creatures.add(f); frame = 0; } for (Creature c : creatures) { if (this.distance(c) < this.getScale()+c.getScale() && c instanceof Tux) { dead_creatures.add(c); } } for (Creature c : creatures) { if (c.getX() < 1 && c instanceof Fox) { dead_creatures.add(c); } } } } import env3d.Env; import java.util.ArrayList; import org.lwjgl.input.Keyboard; /** * A predator and prey simulation. Fox is the predator and Tux is the prey. */ public class Game { private Env env; private boolean finished; private ArrayList<Creature> creatures; private KingTux king; private Snowball ball; private int tuxcounter; private int kills; /** * Constructor for the Game class. It sets up the foxes and tuxes. */ public Game() { // we use a separate ArrayList to keep track of each animal. // our room is 50 x 50. creatures = new ArrayList<Creature>(); for (int i = 0; i < 10; i++) { creatures.add(new Tux((int)(Math.random()*10)+1, 1, (int)(Math.random()*28)+1)); } for (int i = 0; i < 1; i++) { creatures.add(new Fox(60, 1, (int)(Math.random()*28)+1)); } king = new KingTux(25, 1, 35); ball = new Snowball(-400, -400, -400); } /** * Play the game */ public void play() { finished = false; // Create the new environment. Must be done in the same // method as the game loop env = new Env(); // Make the room 50 x 50. env.setRoom(new Room()); // Add all the animals into to the environment for display for (Creature c : creatures) { env.addObject(c); } for (Creature c : creatures) { if (c instanceof Tux) { tuxcounter++; } } env.addObject(king); env.addObject(ball); // Sets up the camera env.setCameraXYZ(30, 50, 55); env.setCameraPitch(-63); // Turn off the default controls env.setDefaultControl(false); // A list to keep track of dead tuxes. ArrayList<Creature> dead_creatures = new ArrayList<Creature>(); ArrayList<Creature> new_creatures = new ArrayList<Creature>(); // The main game loop while (!finished) { if (env.getKey() == 1 || tuxcounter == 0) { finished = true; } env.setDisplayStr("Tuxes: " + tuxcounter, 15, 0); env.setDisplayStr("Kills: " + kills, 140, 0); processInput(); ball.move(); king.check(); // Move each fox and tux. for (Creature c : creatures) { c.move(creatures, dead_creatures, new_creatures); } for (Creature c : creatures) { if (c.distance(ball) < c.getScale()+ball.getScale() && c instanceof Fox) { dead_creatures.add(c); ball.setX(-400); ball.setY(-400); ball.setZ(-400); kills++; } } // Clean up of the dead tuxes. for (Creature c : dead_creatures) { if (c instanceof Tux) { tuxcounter--; } env.removeObject(c); creatures.remove(c); } for (Creature c : new_creatures) { creatures.add(c); env.addObject(c); } // we clear the ArrayList for the next loop. We could create a new one // every loop but that would be very inefficient. dead_creatures.clear(); new_creatures.clear(); // Update display env.advanceOneFrame(); } // Just a little clean up env.exit(); } private void processInput() { int keyDown = env.getKeyDown(); int key = env.getKey(); if (keyDown == 203) { king.setX(king.getX()-1); } else if (keyDown == 205) { king.setX(king.getX()+1); } if (ball.getX() <= -400 && key == Keyboard.KEY_S) { ball.setX(king.getX()); ball.setY(king.getY()); ball.setZ(king.getZ()); } } /** * Main method to launch the program. */ public static void main(String args[]) { (new Game()).play(); } } /**** CREATURE CLASS ****/ /* (Parent class to Tux, Fox, and KingTux) */ import env3d.EnvObject; import java.util.ArrayList; abstract public class Creature extends EnvObject { private int frame; private double rand; /** * Constructor for objects of class Creature */ public Creature(double x, double y, double z) { setX(x); setY(y); setZ(z); setScale(1); rand = Math.random(); } private void randomGenerator() { rand = Math.random(); } public void move(ArrayList<Creature> creatures, ArrayList<Creature> dead_creatures, ArrayList<Creature> new_creatures) { frame++; if (frame > 12) { randomGenerator(); frame = 0; } // if (rand < 0.25) { // setX(getX()+0.3); // setRotateY(90); // } else if (rand < 0.5) { // setX(getX()-0.3); // setRotateY(270); // } else if (rand < 0.75) { // setZ(getZ()+0.3); // setRotateY(0); // } else if (rand < 1) { // setZ(getZ()-0.3); // setRotateY(180); // } if (rand < 0.5) { setRotateY(getRotateY()-7); } else if (rand < 1) { setRotateY(getRotateY()+7); } setX(getX()+Math.sin(Math.toRadians(getRotateY()))*0.5); setZ(getZ()+Math.cos(Math.toRadians(getRotateY()))*0.5); if (getX() < getScale()) setX(getScale()); if (getX() > 50-getScale()) setX(50 - getScale()); if (getZ() < getScale()) setZ(getScale()); if (getZ() > 50-getScale()) setZ(50 - getScale()); // The move method now handles collision detection if (this instanceof Fox) { for (Creature c : creatures) { if (c.distance(this) < c.getScale()+this.getScale() && c instanceof Tux) { dead_creatures.add(c); } } } } } The rest of the classes are a bit trivial to this specific problem.

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  • Why is syslog so much slower than file IO?

    - by ceving
    I wrote a simple test program to measure the performance of the syslog function. This are the results of my test system: (Debian 6.0.2 with Linux 2.6.32-5-amd64) Test Case Calls Payload Duration Thoughput [] [MB] [s] [MB/s] -------------------- ---------- ---------- ---------- ---------- syslog 200000 10.00 7.81 1.28 syslog %s 200000 10.00 9.94 1.01 write /dev/null 200000 10.00 0.03 343.93 printf %s 200000 10.00 0.13 76.29 The test program did 200000 system calls writing 50 Bytes of data during each call. Why is Syslog more than ten times slower than file IO? This is the program I used to perform the test: #include <fcntl.h> #include <stdio.h> #include <string.h> #include <sys/stat.h> #include <sys/time.h> #include <sys/types.h> #include <syslog.h> #include <unistd.h> const int iter = 200000; const char msg[] = "123456789 123456789 123456789 123456789 123456789"; struct timeval t0; struct timeval t1; void start () { gettimeofday (&t0, (void*)0); } void stop () { gettimeofday (&t1, (void*)0); } void report (char *action) { double dt = (double)t1.tv_sec - (double)t0.tv_sec + 1e-6 * ((double)t1.tv_usec - (double)t0.tv_usec); double mb = 1e-6 * sizeof (msg) * iter; if (action == NULL) printf ("Test Case Calls Payload Duration Thoughput \n" " [] [MB] [s] [MB/s] \n" "-------------------- ---------- ---------- ---------- ----------\n"); else { if (strlen (action) > 20) action[20] = 0; printf ("%-20s %-10d %-10.2f %-10.2f %-10.2f\n", action, iter, mb, dt, mb / dt); } } void test_syslog () { int i; openlog ("test_syslog", LOG_PID | LOG_NDELAY, LOG_LOCAL0); start (); for (i = 0; i < iter; i++) syslog (LOG_DEBUG, msg); stop (); closelog (); report ("syslog"); } void test_syslog_format () { int i; openlog ("test_syslog", LOG_PID | LOG_NDELAY, LOG_LOCAL0); start (); for (i = 0; i < iter; i++) syslog (LOG_DEBUG, "%s", msg); stop (); closelog (); report ("syslog %s"); } void test_write_devnull () { int i, fd; fd = open ("/dev/null", O_WRONLY); start (); for (i = 0; i < iter; i++) write (fd, msg, sizeof(msg)); stop (); close (fd); report ("write /dev/null"); } void test_printf () { int i; FILE *fp; fp = fopen ("/tmp/test_printf", "w"); start (); for (i = 0; i < iter; i++) fprintf (fp, "%s", msg); stop (); fclose (fp); report ("printf %s"); } int main (int argc, char **argv) { report (NULL); test_syslog (); test_syslog_format (); test_write_devnull (); test_printf (); }

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  • Single hardware unit to protect web servers and implement smart publishing

    - by Maxim V. Pavlov
    Thus far we've been using the combination of Forefront TMG 2010 as an edge firewall + intrusion prevention system + web site publishing mechanism in the data center to work with a few web server machines. Since we develop on ASP.NET, we are IIS and in general - Microsoft crowd. Since TMG is being deprecated, we need to come up with a hardware alternative to protect and serve our data center web cloud. Could you please advise a hardware or virtual appliance solution that can provide routing, flood prevention and smart web-site publishing (one IP - many web sites based on domain name filter) all in one. Even if it is hard to configure, as long as it covers all these features, we will invest to learn and replace TMG eventually.

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  • MySQL Database Query Problem

    - by moustafa
    I need your help!!!. I need to query a table in my database that has record of goods sold. I want the query to detect a particular product and also calculate the quantity sold. The product are 300 now, but it would increase in the future. Below is a sample of my DB Table #---------------------------- # Table structure for litorder #---------------------------- CREATE TABLE `litorder` ( `id` int(10) NOT NULL auto_increment, `name` varchar(50) NOT NULL default '', `address` varchar(50) NOT NULL default '', `xdate` date NOT NULL default '0000-00-00', `ref` varchar(20) NOT NULL default '', `code1` varchar(50) NOT NULL default '', `code2` varchar(50) NOT NULL default '', `code3` varchar(50) NOT NULL default '', `code4` varchar(50) NOT NULL default '', `code5` varchar(50) NOT NULL default '', `code6` varchar(50) NOT NULL default '', `code7` varchar(50) NOT NULL default '', `code8` varchar(50) NOT NULL default '', `code9` varchar(50) NOT NULL default '', `code10` varchar(50) NOT NULL default '', `code11` varchar(50) character set latin1 collate latin1_bin NOT NULL default '', `code12` varchar(50) NOT NULL default '', `code13` varchar(50) NOT NULL default '', `code14` varchar(50) NOT NULL default '', `code15` varchar(50) NOT NULL default '', `product1` varchar(100) NOT NULL default '0', `product2` varchar(100) NOT NULL default '0', `product3` varchar(100) NOT NULL default '0', `product4` varchar(100) NOT NULL default '0', `product5` varchar(100) NOT NULL default '0', `product6` varchar(100) NOT NULL default '0', `product7` varchar(100) NOT NULL default '0', `product8` varchar(100) NOT NULL default '0', `product9` varchar(100) NOT NULL default '0', `product10` varchar(100) NOT NULL default '0', `product11` varchar(100) NOT NULL default '0', `product12` varchar(100) NOT NULL default '0', `product13` varchar(100) NOT NULL default '0', `product14` varchar(100) NOT NULL default '0', `product15` varchar(100) NOT NULL default '0', `price1` int(10) NOT NULL default '0', `price2` int(10) NOT NULL default '0', `price3` int(10) NOT NULL default '0', `price4` int(10) NOT NULL default '0', `price5` int(10) NOT NULL default '0', `price6` int(10) NOT NULL default '0', `price7` int(10) NOT NULL default '0', `price8` int(10) NOT NULL default '0', `price9` int(10) NOT NULL default '0', `price10` int(10) NOT NULL default '0', `price11` int(10) NOT NULL default '0', `price12` int(10) NOT NULL default '0', `price13` int(10) NOT NULL default '0', `price14` int(10) NOT NULL default '0', `price15` int(10) NOT NULL default '0', `quantity1` int(10) NOT NULL default '0', `quantity2` int(10) NOT NULL default '0', `quantity3` int(10) NOT NULL default '0', `quantity4` int(10) NOT NULL default '0', `quantity5` int(10) NOT NULL default '0', `quantity6` int(10) NOT NULL default '0', `quantity7` int(10) NOT NULL default '0', `quantity8` int(10) NOT NULL default '0', `quantity9` int(10) NOT NULL default '0', `quantity10` int(10) NOT NULL default '0', `quantity11` int(10) NOT NULL default '0', `quantity12` int(10) NOT NULL default '0', `quantity13` int(10) NOT NULL default '0', `quantity14` int(10) NOT NULL default '0', `quantity15` int(10) NOT NULL default '0', `amount1` int(10) NOT NULL default '0', `amount2` int(10) NOT NULL default '0', `amount3` int(10) NOT NULL default '0', `amount4` int(10) NOT NULL default '0', `amount5` int(10) NOT NULL default '0', `amount6` int(10) NOT NULL default '0', `amount7` int(10) NOT NULL default '0', `amount8` int(10) NOT NULL default '0', `amount9` int(10) NOT NULL default '0', `amount10` int(10) NOT NULL default '0', `amount11` int(10) NOT NULL default '0', `amount12` int(10) NOT NULL default '0', `amount13` int(10) NOT NULL default '0', `amount14` int(10) NOT NULL default '0', `amount15` int(10) NOT NULL default '0', `totalNaira` double(20,0) NOT NULL default '0', `totalDollar` int(20) NOT NULL default '0', PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 COMMENT='InnoDB free: 4096 kB; InnoDB free: 4096 kB; InnoDB free: 409'; #---------------------------- # Records for table litorder #---------------------------- insert into litorder values (27, 'Sanyaolu Fisayo', '14 Adegboyega Street Palmgrove Lagos', '2010-05-31', '', 'DL 001', 'DL 002', 'DL 003', '', '', '', '', '', '', '', '', '', '', '', '', 'AILMENT & PREVENTION DVD- ENGLISH', 'AILMENT & PREVENTION DVD- HAUSA', 'BEAUTY CD', '', '', '', '', '', '', '', '', '', '', '', '', 800, 800, 3000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 16, 20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12800, 12800, 60000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, '85600', 563), (28, 'Irenonse Esther', 'Lagos,Nigeria', '2010-06-01', '', 'DL 005', 'DL 008', 'FC 004', '', '', '', '', '', '', '', '', '', '', '', '', 'GET HEALTHY DVD', 'YOUR FUTURE DVD', 'FOREVER FACE CAP (YELLOW)', '', '', '', '', '', '', '', '', '', '', '', '', 1000, 900, 2000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2000, 1800, 6000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, '9800', 64), (29, 'Kalu Lekway', 'Lagos, Nigeria', '2010-06-01', '', 'DL 001', 'DL 003', '', '', '', '', '', '', '', '', '', '', '', '', '', 'AILMENT & PREVENTION DVD- ENGLISH', 'BEAUTY CD', '', '', '', '', '', '', '', '', '', '', '', '', '', 800, 3000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2400, 18000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, '20400', 133), (30, 'Dele', 'Ilupeju', '2010-06-02', '', 'DL 001', 'DL 003', '', '', '', '', '', '', '', '', '', '', '', '', '', 'AILMENT & PREVENTION DVD- ENGLISH', 'BEAUTY CD', '', '', '', '', '', '', '', '', '', '', '', '', '', 800, 3000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 10, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8000, 30000, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, '38000', 250);

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  • Basic Spatial Data with SQL Server and Entity Framework 5.0

    - by Rick Strahl
    In my most recent project we needed to do a bit of geo-spatial referencing. While spatial features have been in SQL Server for a while using those features inside of .NET applications hasn't been as straight forward as could be, because .NET natively doesn't support spatial types. There are workarounds for this with a few custom project like SharpMap or a hack using the Sql Server specific Geo types found in the Microsoft.SqlTypes assembly that ships with SQL server. While these approaches work for manipulating spatial data from .NET code, they didn't work with database access if you're using Entity Framework. Other ORM vendors have been rolling their own versions of spatial integration. In Entity Framework 5.0 running on .NET 4.5 the Microsoft ORM finally adds support for spatial types as well. In this post I'll describe basic geography features that deal with single location and distance calculations which is probably the most common usage scenario. SQL Server Transact-SQL Syntax for Spatial Data Before we look at how things work with Entity framework, lets take a look at how SQL Server allows you to use spatial data to get an understanding of the underlying semantics. The following SQL examples should work with SQL 2008 and forward. Let's start by creating a test table that includes a Geography field and also a pair of Long/Lat fields that demonstrate how you can work with the geography functions even if you don't have geography/geometry fields in the database. Here's the CREATE command:CREATE TABLE [dbo].[Geo]( [id] [int] IDENTITY(1,1) NOT NULL, [Location] [geography] NULL, [Long] [float] NOT NULL, [Lat] [float] NOT NULL ) Now using plain SQL you can insert data into the table using geography::STGeoFromText SQL CLR function:insert into Geo( Location , long, lat ) values ( geography::STGeomFromText ('POINT(-121.527200 45.712113)', 4326), -121.527200, 45.712113 ) insert into Geo( Location , long, lat ) values ( geography::STGeomFromText ('POINT(-121.517265 45.714240)', 4326), -121.517265, 45.714240 ) insert into Geo( Location , long, lat ) values ( geography::STGeomFromText ('POINT(-121.511536 45.714825)', 4326), -121.511536, 45.714825) The STGeomFromText function accepts a string that points to a geometric item (a point here but can also be a line or path or polygon and many others). You also need to provide an SRID (Spatial Reference System Identifier) which is an integer value that determines the rules for how geography/geometry values are calculated and returned. For mapping/distance functionality you typically want to use 4326 as this is the format used by most mapping software and geo-location libraries like Google and Bing. The spatial data in the Location field is stored in binary format which looks something like this: Once the location data is in the database you can query the data and do simple distance computations very easily. For example to calculate the distance of each of the values in the database to another spatial point is very easy to calculate. Distance calculations compare two points in space using a direct line calculation. For our example I'll compare a new point to all the points in the database. Using the Location field the SQL looks like this:-- create a source point DECLARE @s geography SET @s = geography:: STGeomFromText('POINT(-121.527200 45.712113)' , 4326); --- return the ids select ID, Location as Geo , Location .ToString() as Point , @s.STDistance( Location) as distance from Geo order by distance The code defines a new point which is the base point to compare each of the values to. You can also compare values from the database directly, but typically you'll want to match a location to another location and determine the difference for which you can use the geography::STDistance function. This query produces the following output: The STDistance function returns the straight line distance between the passed in point and the point in the database field. The result for SRID 4326 is always in meters. Notice that the first value passed was the same point so the difference is 0. The other two points are two points here in town in Hood River a little ways away - 808 and 1256 meters respectively. Notice also that you can order the result by the resulting distance, which effectively gives you results that are ordered radially out from closer to further away. This is great for searches of points of interest near a central location (YOU typically!). These geolocation functions are also available to you if you don't use the Geography/Geometry types, but plain float values. It's a little more work, as each point has to be created in the query using the string syntax, but the following code doesn't use a geography field but produces the same result as the previous query.--- using float fields select ID, geography::STGeomFromText ('POINT(' + STR (long, 15,7 ) + ' ' + Str(lat ,15, 7) + ')' , 4326), geography::STGeomFromText ('POINT(' + STR (long, 15,7 ) + ' ' + Str(lat ,15, 7) + ')' , 4326). ToString(), @s.STDistance( geography::STGeomFromText ('POINT(' + STR(long ,15, 7) + ' ' + Str(lat ,15, 7) + ')' , 4326)) as distance from geo order by distance Spatial Data in the Entity Framework Prior to Entity Framework 5.0 on .NET 4.5 consuming of the data above required using stored procedures or raw SQL commands to access the spatial data. In Entity Framework 5 however, Microsoft introduced the new DbGeometry and DbGeography types. These immutable location types provide a bunch of functionality for manipulating spatial points using geometry functions which in turn can be used to do common spatial queries like I described in the SQL syntax above. The DbGeography/DbGeometry types are immutable, meaning that you can't write to them once they've been created. They are a bit odd in that you need to use factory methods in order to instantiate them - they have no constructor() and you can't assign to properties like Latitude and Longitude. Creating a Model with Spatial Data Let's start by creating a simple Entity Framework model that includes a Location property of type DbGeography: public class GeoLocationContext : DbContext { public DbSet<GeoLocation> Locations { get; set; } } public class GeoLocation { public int Id { get; set; } public DbGeography Location { get; set; } public string Address { get; set; } } That's all there's to it. When you run this now against SQL Server, you get a Geography field for the Location property, which looks the same as the Location field in the SQL examples earlier. Adding Spatial Data to the Database Next let's add some data to the table that includes some latitude and longitude data. An easy way to find lat/long locations is to use Google Maps to pinpoint your location, then right click and click on What's Here. Click on the green marker to get the GPS coordinates. To add the actual geolocation data create an instance of the GeoLocation type and use the DbGeography.PointFromText() factory method to create a new point to assign to the Location property:[TestMethod] public void AddLocationsToDataBase() { var context = new GeoLocationContext(); // remove all context.Locations.ToList().ForEach( loc => context.Locations.Remove(loc)); context.SaveChanges(); var location = new GeoLocation() { // Create a point using native DbGeography Factory method Location = DbGeography.PointFromText( string.Format("POINT({0} {1})", -121.527200,45.712113) ,4326), Address = "301 15th Street, Hood River" }; context.Locations.Add(location); location = new GeoLocation() { Location = CreatePoint(45.714240, -121.517265), Address = "The Hatchery, Bingen" }; context.Locations.Add(location); location = new GeoLocation() { // Create a point using a helper function (lat/long) Location = CreatePoint(45.708457, -121.514432), Address = "Kaze Sushi, Hood River" }; context.Locations.Add(location); location = new GeoLocation() { Location = CreatePoint(45.722780, -120.209227), Address = "Arlington, OR" }; context.Locations.Add(location); context.SaveChanges(); } As promised, a DbGeography object has to be created with one of the static factory methods provided on the type as the Location.Longitude and Location.Latitude properties are read only. Here I'm using PointFromText() which uses a "Well Known Text" format to specify spatial data. In the first example I'm specifying to create a Point from a longitude and latitude value, using an SRID of 4326 (just like earlier in the SQL examples). You'll probably want to create a helper method to make the creation of Points easier to avoid that string format and instead just pass in a couple of double values. Here's my helper called CreatePoint that's used for all but the first point creation in the sample above:public static DbGeography CreatePoint(double latitude, double longitude) { var text = string.Format(CultureInfo.InvariantCulture.NumberFormat, "POINT({0} {1})", longitude, latitude); // 4326 is most common coordinate system used by GPS/Maps return DbGeography.PointFromText(text, 4326); } Using the helper the syntax becomes a bit cleaner, requiring only a latitude and longitude respectively. Note that my method intentionally swaps the parameters around because Latitude and Longitude is the common format I've seen with mapping libraries (especially Google Mapping/Geolocation APIs with their LatLng type). When the context is changed the data is written into the database using the SQL Geography type which looks the same as in the earlier SQL examples shown. Querying Once you have some location data in the database it's now super easy to query the data and find out the distance between locations. A common query is to ask for a number of locations that are near a fixed point - typically your current location and order it by distance. Using LINQ to Entities a query like this is easy to construct:[TestMethod] public void QueryLocationsTest() { var sourcePoint = CreatePoint(45.712113, -121.527200); var context = new GeoLocationContext(); // find any locations within 5 kilometers ordered by distance var matches = context.Locations .Where(loc => loc.Location.Distance(sourcePoint) < 5000) .OrderBy( loc=> loc.Location.Distance(sourcePoint) ) .Select( loc=> new { Address = loc.Address, Distance = loc.Location.Distance(sourcePoint) }); Assert.IsTrue(matches.Count() > 0); foreach (var location in matches) { Console.WriteLine("{0} ({1:n0} meters)", location.Address, location.Distance); } } This example produces: 301 15th Street, Hood River (0 meters)The Hatchery, Bingen (809 meters)Kaze Sushi, Hood River (1,074 meters)   The first point in the database is the same as my source point I'm comparing against so the distance is 0. The other two are within the 5 mile radius, while the Arlington location which is 65 miles or so out is not returned. The result is ordered by distance from closest to furthest away. In the code, I first create a source point that is the basis for comparison. The LINQ query then selects all locations that are within 5km of the source point using the Location.Distance() function, which takes a source point as a parameter. You can either use a pre-defined value as I'm doing here, or compare against another database DbGeography property (say when you have to points in the same database for things like routes). What's nice about this query syntax is that it's very clean and easy to read and understand. You can calculate the distance and also easily order by the distance to provide a result that shows locations from closest to furthest away which is a common scenario for any application that places a user in the context of several locations. It's now super easy to accomplish this. Meters vs. Miles As with the SQL Server functions, the Distance() method returns data in meters, so if you need to work with miles or feet you need to do some conversion. Here are a couple of helpers that might be useful (can be found in GeoUtils.cs of the sample project):/// <summary> /// Convert meters to miles /// </summary> /// <param name="meters"></param> /// <returns></returns> public static double MetersToMiles(double? meters) { if (meters == null) return 0F; return meters.Value * 0.000621371192; } /// <summary> /// Convert miles to meters /// </summary> /// <param name="miles"></param> /// <returns></returns> public static double MilesToMeters(double? miles) { if (miles == null) return 0; return miles.Value * 1609.344; } Using these two helpers you can query on miles like this:[TestMethod] public void QueryLocationsMilesTest() { var sourcePoint = CreatePoint(45.712113, -121.527200); var context = new GeoLocationContext(); // find any locations within 5 miles ordered by distance var fiveMiles = GeoUtils.MilesToMeters(5); var matches = context.Locations .Where(loc => loc.Location.Distance(sourcePoint) <= fiveMiles) .OrderBy(loc => loc.Location.Distance(sourcePoint)) .Select(loc => new { Address = loc.Address, Distance = loc.Location.Distance(sourcePoint) }); Assert.IsTrue(matches.Count() > 0); foreach (var location in matches) { Console.WriteLine("{0} ({1:n1} miles)", location.Address, GeoUtils.MetersToMiles(location.Distance)); } } which produces: 301 15th Street, Hood River (0.0 miles)The Hatchery, Bingen (0.5 miles)Kaze Sushi, Hood River (0.7 miles) Nice 'n simple. .NET 4.5 Only Note that DbGeography and DbGeometry are exclusive to Entity Framework 5.0 (not 4.4 which ships in the same NuGet package or installer) and requires .NET 4.5. That's because the new DbGeometry and DbGeography (and related) types are defined in the 4.5 version of System.Data.Entity which is a CLR assembly and is only updated by major versions of .NET. Why this decision was made to add these types to System.Data.Entity rather than to the frequently updated EntityFramework assembly that would have possibly made this work in .NET 4.0 is beyond me, especially given that there are no native .NET framework spatial types to begin with. I find it also odd that there is no native CLR spatial type. The DbGeography and DbGeometry types are specific to Entity Framework and live on those assemblies. They will also work for general purpose, non-database spatial data manipulation, but then you are forced into having a dependency on System.Data.Entity, which seems a bit silly. There's also a System.Spatial assembly that's apparently part of WCF Data Services which in turn don't work with Entity framework. Another example of multiple teams at Microsoft not communicating and implementing the same functionality (differently) in several different places. Perplexed as a I may be, for EF specific code the Entity framework specific types are easy to use and work well. Working with pre-.NET 4.5 Entity Framework and Spatial Data If you can't go to .NET 4.5 just yet you can also still use spatial features in Entity Framework, but it's a lot more work as you can't use the DbContext directly to manipulate the location data. You can still run raw SQL statements to write data into the database and retrieve results using the same TSQL syntax I showed earlier using Context.Database.ExecuteSqlCommand(). Here's code that you can use to add location data into the database:[TestMethod] public void RawSqlEfAddTest() { string sqlFormat = @"insert into GeoLocations( Location, Address) values ( geography::STGeomFromText('POINT({0} {1})', 4326),@p0 )"; var sql = string.Format(sqlFormat,-121.527200, 45.712113); Console.WriteLine(sql); var context = new GeoLocationContext(); Assert.IsTrue(context.Database.ExecuteSqlCommand(sql,"301 N. 15th Street") > 0); } Here I'm using the STGeomFromText() function to add the location data. Note that I'm using string.Format here, which usually would be a bad practice but is required here. I was unable to use ExecuteSqlCommand() and its named parameter syntax as the longitude and latitude parameters are embedded into a string. Rest assured it's required as the following does not work:string sqlFormat = @"insert into GeoLocations( Location, Address) values ( geography::STGeomFromText('POINT(@p0 @p1)', 4326),@p2 )";context.Database.ExecuteSqlCommand(sql, -121.527200, 45.712113, "301 N. 15th Street") Explicitly assigning the point value with string.format works however. There are a number of ways to query location data. You can't get the location data directly, but you can retrieve the point string (which can then be parsed to get Latitude and Longitude) and you can return calculated values like distance. Here's an example of how to retrieve some geo data into a resultset using EF's and SqlQuery method:[TestMethod] public void RawSqlEfQueryTest() { var sqlFormat = @" DECLARE @s geography SET @s = geography:: STGeomFromText('POINT({0} {1})' , 4326); SELECT Address, Location.ToString() as GeoString, @s.STDistance( Location) as Distance FROM GeoLocations ORDER BY Distance"; var sql = string.Format(sqlFormat, -121.527200, 45.712113); var context = new GeoLocationContext(); var locations = context.Database.SqlQuery<ResultData>(sql); Assert.IsTrue(locations.Count() > 0); foreach (var location in locations) { Console.WriteLine(location.Address + " " + location.GeoString + " " + location.Distance); } } public class ResultData { public string GeoString { get; set; } public double Distance { get; set; } public string Address { get; set; } } Hopefully you don't have to resort to this approach as it's fairly limited. Using the new DbGeography/DbGeometry types makes this sort of thing so much easier. When I had to use code like this before I typically ended up retrieving data pks only and then running another query with just the PKs to retrieve the actual underlying DbContext entities. This was very inefficient and tedious but it did work. Summary For the current project I'm working on we actually made the switch to .NET 4.5 purely for the spatial features in EF 5.0. This app heavily relies on spatial queries and it was worth taking a chance with pre-release code to get this ease of integration as opposed to manually falling back to stored procedures or raw SQL string queries to return spatial specific queries. Using native Entity Framework code makes life a lot easier than the alternatives. It might be a late addition to Entity Framework, but it sure makes location calculations and storage easy. Where do you want to go today? ;-) Resources Download Sample Project© Rick Strahl, West Wind Technologies, 2005-2012Posted in ADO.NET  Sql Server  .NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • SQLBits VI session submission - Today is your last day

    - by simonsabin
    We will be deciding on the sessions tomorrow (Tuesday 8th March) so make sure you get your session in for SQLBits quick. Don't forget we are focussing on performance an scalability so make sure your session covers one or both of these. To submit your session Step 1 - Complete your Speaker Profile Step 2 - Submit My Sessions

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  • SQLBits VI session submission - Today is your last day

    - by simonsabin
    We will be deciding on the sessions tomorrow (Tuesday 8th March) so make sure you get your session in for SQLBits quick. Don't forget we are focussing on performance an scalability so make sure your session covers one or both of these. To submit your session Step 1 - Complete your Speaker Profile Step 2 - Submit My Sessions

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  • ASP.NET MVC 2 Model Binding for a Collection

    - by nmarun
    Yes, my yet another post on Model Binding (previous one is here), but this one uses features presented in MVC 2. How I got to writing this blog? Well, I’m on a project where we’re doing some MVC things for a shopping cart. Let me show you what I was working with. Below are my model classes: 1: public class Product 2: { 3: public int Id { get; set; } 4: public string Name { get; set; } 5: public int Quantity { get; set; } 6: public decimal UnitPrice { get; set; } 7: } 8:   9: public class Totals 10: { 11: public decimal SubTotal { get; set; } 12: public decimal Tax { get; set; } 13: public decimal Total { get; set; } 14: } 15:   16: public class Basket 17: { 18: public List<Product> Products { get; set; } 19: public Totals Totals { get; set;} 20: } The view looks as below:  1: <h2>Shopping Cart</h2> 2:   3: <% using(Html.BeginForm()) { %> 4: 5: <h3>Products</h3> 6: <% for (int i = 0; i < Model.Products.Count; i++) 7: { %> 8: <div style="width: 100px;float:left;">Id</div> 9: <div style="width: 100px;float:left;"> 10: <%= Html.TextBox("ID", Model.Products[i].Id) %> 11: </div> 12: <div style="clear:both;"></div> 13: <div style="width: 100px;float:left;">Name</div> 14: <div style="width: 100px;float:left;"> 15: <%= Html.TextBox("Name", Model.Products[i].Name) %> 16: </div> 17: <div style="clear:both;"></div> 18: <div style="width: 100px;float:left;">Quantity</div> 19: <div style="width: 100px;float:left;"> 20: <%= Html.TextBox("Quantity", Model.Products[i].Quantity)%> 21: </div> 22: <div style="clear:both;"></div> 23: <div style="width: 100px;float:left;">Unit Price</div> 24: <div style="width: 100px;float:left;"> 25: <%= Html.TextBox("UnitPrice", Model.Products[i].UnitPrice)%> 26: </div> 27: <div style="clear:both;"><hr /></div> 28: <% } %> 29: 30: <h3>Totals</h3> 31: <div style="width: 100px;float:left;">Sub Total</div> 32: <div style="width: 100px;float:left;"> 33: <%= Html.TextBox("SubTotal", Model.Totals.SubTotal)%> 34: </div> 35: <div style="clear:both;"></div> 36: <div style="width: 100px;float:left;">Tax</div> 37: <div style="width: 100px;float:left;"> 38: <%= Html.TextBox("Tax", Model.Totals.Tax)%> 39: </div> 40: <div style="clear:both;"></div> 41: <div style="width: 100px;float:left;">Total</div> 42: <div style="width: 100px;float:left;"> 43: <%= Html.TextBox("Total", Model.Totals.Total)%> 44: </div> 45: <div style="clear:both;"></div> 46: <p /> 47: <input type="submit" name="Submit" value="Submit" /> 48: <% } %> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Nothing fancy, just a bunch of div’s containing textboxes and a submit button. Just make note that the textboxes have the same name as the property they are going to display. Yea, yea, I know. I’m displaying unit price as a textbox instead of a label, but that’s beside the point (and trust me, this will not be how it’ll look on the production site!!). The way my controller works is that initially two dummy products are added to the basked object and the Totals are calculated based on what products were added in what quantities and their respective unit price. So when the page loads in edit mode, where the user can change the quantity and hit the submit button. In the ‘post’ version of the action method, the Totals get recalculated and the new total will be displayed on the screen. Here’s the code: 1: public ActionResult Index() 2: { 3: Product product1 = new Product 4: { 5: Id = 1, 6: Name = "Product 1", 7: Quantity = 2, 8: UnitPrice = 200m 9: }; 10:   11: Product product2 = new Product 12: { 13: Id = 2, 14: Name = "Product 2", 15: Quantity = 1, 16: UnitPrice = 150m 17: }; 18:   19: List<Product> products = new List<Product> { product1, product2 }; 20:   21: Basket basket = new Basket 22: { 23: Products = products, 24: Totals = ComputeTotals(products) 25: }; 26: return View(basket); 27: } 28:   29: [HttpPost] 30: public ActionResult Index(Basket basket) 31: { 32: basket.Totals = ComputeTotals(basket.Products); 33: return View(basket); 34: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } That’s that. Now I run the app, I see two products with the totals section below them. I look at the view source and I see that the input controls have the right ID, the right name and the right value as well. 1: <input id="ID" name="ID" type="text" value="1" /> 2: <input id="Name" name="Name" type="text" value="Product 1" /> 3: ... 4: <input id="ID" name="ID" type="text" value="2" /> 5: <input id="Name" name="Name" type="text" value="Product 2" /> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } So just as a regular user would do, I change the quantity value of one of the products and hit the submit button. The ‘post’ version of the Index method gets called and I had put a break-point on line 32 in the above snippet. When I hovered my mouse on the ‘basked’ object, happily assuming that the object would be all bound and ready for use, I was surprised to see both basket.Products and basket.Totals were null. Huh? A little research and I found out that the reason the DefaultModelBinder could not do its job is because of a naming mismatch on the input controls. What I mean is that when you have to bind to a custom .net type, you need more than just the property name. You need to pass a qualified name to the name property of the input control. I modified my view and the emitted code looked as below: 1: <input id="Product_Name" name="Product.Name" type="text" value="Product 1" /> 2: ... 3: <input id="Product_Name" name="Product.Name" type="text" value="Product 2" /> 4: ... 5: <input id="Totals_SubTotal" name="Totals.SubTotal" type="text" value="550" /> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now, I update the quantity and hit the submit button and I see that the Totals object is populated, but the Products list is still null. Once again I went: ‘Hmm.. time for more research’. I found out that the way to do this is to provide the name as: 1: <%= Html.TextBox(string.Format("Products[{0}].ID", i), Model.Products[i].Id) %> 2: <!-- this will be rendered as --> 3: <input id="Products_0__ID" name="Products[0].ID" type="text" value="1" /> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } It was only now that I was able to see both the products and the totals being properly bound in the ‘post’ action method. Somehow, I feel this is kinda ‘clunky’ way of doing things. Seems like people at MS felt in a similar way and offered us a much cleaner way to solve this issue. The simple solution is that instead of using a Textbox, we can either use a TextboxFor or an EditorFor helper method. This one directly spits out the name of the input property as ‘Products[0].ID and so on. Cool right? I totally fell for this and changed my UI to contain EditorFor helper method. At this point, I ran the application, changed the quantity field and pressed the submit button. Of course my basket object parameter in my action method was correctly bound after these changes. I let the app complete the rest of the lines in the action method. When the page finally rendered, I did see that the quantity was changed to what I entered before the post. But, wait a minute, the totals section did not reflect the changes and showed the old values. My status: COMPLETELY PUZZLED! Just to recap, this is what my ‘post’ Index method looked like: 1: [HttpPost] 2: public ActionResult Index(Basket basket) 3: { 4: basket.Totals = ComputeTotals(basket.Products); 5: return View(basket); 6: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } A careful debug confirmed that the basked.Products[0].Quantity showed the updated value and the ComputeTotals() method also returns the correct totals. But still when I passed this basket object, it ended up showing the old totals values only. I began playing a bit with the code and my first guess was that the input controls got their values from the ModelState object. For those who don’t know, the ModelState is a temporary storage area that ASP.NET MVC uses to retain incoming attempted values plus binding and validation errors. Also, the fact that input controls populate the values using data taken from: Previously attempted values recorded in the ModelState["name"].Value.AttemptedValue Explicitly provided value (<%= Html.TextBox("name", "Some value") %>) ViewData, by calling ViewData.Eval("name") FYI: ViewData dictionary takes precedence over ViewData's Model properties – read more here. These two indicators led to my guess. It took me quite some time, but finally I hit this post where Brad brilliantly explains why this is the preferred behavior. My guess was right and I, accordingly modified my code to reflect the following way: 1: [HttpPost] 2: public ActionResult Index(Basket basket) 3: { 4: // read the following posts to see why the ModelState 5: // needs to be cleared before passing it the view 6: // http://forums.asp.net/t/1535846.aspx 7: // http://forums.asp.net/p/1527149/3687407.aspx 8: if (ModelState.IsValid) 9: { 10: ModelState.Clear(); 11: } 12:   13: basket.Totals = ComputeTotals(basket.Products); 14: return View(basket); 15: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } What this does is that in the case where your ModelState IS valid, it clears the dictionary. This enables the values to be read from the model directly and not from the ModelState. So the verdict is this: If you need to pass other parameters (like html attributes and the like) to your input control, use 1: <%= Html.TextBox(string.Format("Products[{0}].ID", i), Model.Products[i].Id) %> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Since, in EditorFor, there is no direct and simple way of passing this information to the input control. If you don’t have to pass any such ‘extra’ piece of information to the control, then go the EditorFor way. The code used in the post can be found here.

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  • Converting System.DateTime to JD Edwards Date

    - by Christopher House
    As a follow up to my post the other day on converting a JD Edwards date to a .Net System.DateTime, here is some code to convert a System.DateTime to a JD Edwards date: public static double ToJdeDate(DateTime theDate) {   double jdeDate = 0d;   int dayInYear = theDate.DayOfYear;   int theYear = theDate.Year - 1900;   jdeDate = (theYear * 1000) + dayInYear;   return jdeDate; }

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  • How to speed up this simple mysql query?

    - by Jim Thio
    The query is simple: SELECT TB.ID, TB.Latitude, TB.Longitude, 111151.29341326*SQRT(pow(-6.185-TB.Latitude,2)+pow(106.773-TB.Longitude,2)*cos(-6.185*0.017453292519943)*cos(TB.Latitude*0.017453292519943)) AS Distance FROM `tablebusiness` AS TB WHERE -6.2767668133836 < TB.Latitude AND TB.Latitude < -6.0932331866164 AND FoursquarePeopleCount >5 AND 106.68123318662 < TB.Longitude AND TB.Longitude <106.86476681338 ORDER BY Distance See, we just look at all business within a rectangle. 1.6 million rows. Within that small rectangle there are only 67,565 businesses. The structure of the table is 1 ID varchar(250) utf8_unicode_ci No None Change Change Drop Drop More Show more actions 2 Email varchar(400) utf8_unicode_ci Yes NULL Change Change Drop Drop More Show more actions 3 InBuildingAddress varchar(400) utf8_unicode_ci Yes NULL Change Change Drop Drop More Show more actions 4 Price int(10) Yes NULL Change Change Drop Drop More Show more actions 5 Street varchar(400) utf8_unicode_ci Yes NULL Change Change Drop Drop More Show more actions 6 Title varchar(400) utf8_unicode_ci Yes NULL Change Change Drop Drop More Show more actions 7 Website varchar(400) utf8_unicode_ci Yes NULL Change Change Drop Drop More Show more actions 8 Zip varchar(400) utf8_unicode_ci Yes NULL Change Change Drop Drop More Show more actions 9 Rating Star double Yes NULL Change Change Drop Drop More Show more actions 10 Rating Weight double Yes NULL Change Change Drop Drop More Show more actions 11 Latitude double Yes NULL Change Change Drop Drop More Show more actions 12 Longitude double Yes NULL Change Change Drop Drop More Show more actions 13 Building varchar(200) utf8_unicode_ci Yes NULL Change Change Drop Drop More Show more actions 14 City varchar(100) utf8_unicode_ci No None Change Change Drop Drop More Show more actions 15 OpeningHour varchar(400) utf8_unicode_ci Yes NULL Change Change Drop Drop More Show more actions 16 TimeStamp timestamp on update CURRENT_TIMESTAMP No CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP Change Change Drop Drop More Show more actions 17 CountViews int(11) Yes NULL Change Change Drop Drop More Show more actions The indexes are: Edit Edit Drop Drop PRIMARY BTREE Yes No ID 1965990 A Edit Edit Drop Drop City BTREE No No City 131066 A Edit Edit Drop Drop Building BTREE No No Building 21 A YES Edit Edit Drop Drop OpeningHour BTREE No No OpeningHour (255) 21 A YES Edit Edit Drop Drop Email BTREE No No Email (255) 21 A YES Edit Edit Drop Drop InBuildingAddress BTREE No No InBuildingAddress (255) 21 A YES Edit Edit Drop Drop Price BTREE No No Price 21 A YES Edit Edit Drop Drop Street BTREE No No Street (255) 982995 A YES Edit Edit Drop Drop Title BTREE No No Title (255) 1965990 A YES Edit Edit Drop Drop Website BTREE No No Website (255) 491497 A YES Edit Edit Drop Drop Zip BTREE No No Zip (255) 178726 A YES Edit Edit Drop Drop Rating Star BTREE No No Rating Star 21 A YES Edit Edit Drop Drop Rating Weight BTREE No No Rating Weight 21 A YES Edit Edit Drop Drop Latitude BTREE No No Latitude 1965990 A YES Edit Edit Drop Drop Longitude BTREE No No Longitude 1965990 A YES The query took forever. I think there has to be something wrong there. Showing rows 0 - 29 ( 67,565 total, Query took 12.4767 sec)

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  • Looking for a user suggestion script

    - by Jamison
    I'm looking for a script that would easily fit or be customized to work as a suggestion script where users can submit suggestions anonymously and have them be displayed on one page and either upvoted or downvoted like digg or reddit without user accounts. Basically i want users to be able to submit an idea and the other users like or dislike it and no one is track for voting, commenting or submitting.

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  • Conferences: Starting the round for 2011 with Mix

    - by Enrique Lima
    There are several conferences lining up for 2011.  There are some private conferences I will be participating in and some other where there is an invitation to submit content for consideration.  That is the case with Mix 2011. The date:  April 12-14, 2011 The venue: Mandalay Bay, Las Vegas Here is the general information: http://live.visitmix.com/ To submit content: http://live.visitmix.com/opencall

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  • Sliding collision response

    - by dbostream
    I have been reading plenty of tutorials about sliding collision responses yet I am not able to implement it properly in my project. What I want to do is make a puck slide along the rounded corner boards of a hockey rink. In my latest attempt the puck does slide along the boards but there are some strange velocity behaviors. First of all the puck slows down a lot pretty much right away and then it slides for awhile and stops before exiting the corner. Even if I double the speed I get a similar behavior and the puck does not make it out of the corner. I used some ideas from this document http://www.peroxide.dk/papers/collision/collision.pdf. This is what I have: Update method called from the game loop when it is time to update the puck (I removed some irrelevant parts). I use two states (current, previous) which are used to interpolate the position during rendering. public override void Update(double fixedTimeStep) { /* Acceleration is set to 0 for now. */ Acceleration.Zero(); PreviousState = CurrentState; _collisionRecursionDepth = 0; CurrentState.Position = SlidingCollision(CurrentState.Position, CurrentState.Velocity * fixedTimeStep + 0.5 * Acceleration * fixedTimeStep * fixedTimeStep); /* Should not this be affected by a sliding collision? and not only the position. */ CurrentState.Velocity = CurrentState.Velocity + Acceleration * fixedTimeStep; Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private Vector2 SlidingCollision(Vector2 position, Vector2 velocity) { if(_collisionRecursionDepth > 5) return position; bool collisionFound = false; Vector2 futurePosition = position + velocity; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ if(!collisionFound) return futurePosition; /* If no collision was detected it is safe to move to the future position. */ /* It is not exactly the intersection point, but slightly before. */ Vector2 newPosition = intersectionPoint; /* oldVelocity is set to the distance from the newPosition(intersection point) to the position it had moved to had it not collided. */ Vector2 oldVelocity = futurePosition - newPosition; /* Project the distance left to move along the intersection normal. */ Vector2 newVelocity = oldVelocity - intersectionPointNormal * oldVelocity.DotProduct(intersectionPointNormal); if(newVelocity.LengthSq() < 0.001) return newPosition; /* If almost no speed, no need to continue. */ _collisionRecursionDepth++; return SlidingCollision(newPosition, newVelocity); } What am I doing wrong with the velocity? I have been staring at this for very long so I have gone blind. I have tried different values of recursion depth but it does not seem to make it better. Let me know if you need more information. I appreciate any help. EDIT: A combination of Patrick Hughes' and teodron's answers solved the velocity problem (I think), thanks a lot! This is the new code: I decided to use a separate recursion method now too since I don't want to recalculate the acceleration in each recursion. public override void Update(double fixedTimeStep) { Acceleration.Zero();// = CalculateAcceleration(fixedTimeStep); PreviousState = new MovingEntityState(CurrentState.Position, CurrentState.Velocity); CurrentState = SlidingCollision(CurrentState, fixedTimeStep); Heading = Vector2.NormalizeRet(CurrentState.Velocity); } private MovingEntityState SlidingCollision(MovingEntityState state, double timeStep) { bool collisionFound = false; /* Calculate the next position given no detected collision. */ Vector2 futurePosition = state.Position + state.Velocity * timeStep; Vector2 intersectionPoint = new Vector2(); Vector2 intersectionPointNormal = new Vector2(); /* I did not include the collision detection code, if a collision is detected the intersection point and normal in that point is returned. */ /* If no collision was detected it is safe to move to the future position. */ if (!collisionFound) return new MovingEntityState(futurePosition, state.Velocity); /* Set new position to the intersection point (slightly before). */ Vector2 newPosition = intersectionPoint; /* Project the new velocity along the intersection normal. */ Vector2 newVelocity = state.Velocity - 1.90 * intersectionPointNormal * state.Velocity.DotProduct(intersectionPointNormal); /* Calculate the time of collision. */ double timeOfCollision = Math.Sqrt((newPosition - state.Position).LengthSq() / (futurePosition - state.Position).LengthSq()); /* Calculate new time step, remaining time of full step after the collision * current time step. */ double newTimeStep = timeStep * (1 - timeOfCollision); return SlidingCollision(new MovingEntityState(newPosition, newVelocity), newTimeStep); } Even though the code above seems to slide the puck correctly please have a look at it. I have a few questions, if I don't multiply by 1.90 in the newVelocity calculation it doesn't work (I get a stack overflow when the puck enters the corner because the timeStep decreases very slowly - a collision is found early in every recursion), why is that? what does 1.90 really do and why 1.90? Also I have a new problem, the puck does not move parallell to the short side after exiting the curve; to be more exact it moves outside the rink (I am not checking for any collisions with the short side at the moment). When I perform the collision detection I first check that the puck is in the correct quadrant. For example bottom-right corner is quadrant four i.e. circleCenter.X < puck.X && circleCenter.Y puck.Y is this a problem? or should the short side of the rink be the one to make the puck go parallell to it and not the last collision in the corner? EDIT2: This is the code I use for collision detection, maybe it has something to do with the fact that I can't make the puck slide (-1.0) but only reflect (-2.0): /* Point is the current position (not the predicted one) and quadrant is 4 for the bottom-right corner for example. */ if (GeometryHelper.PointInCircleQuadrant(circleCenter, circleRadius, state.Position, quadrant)) { /* The line is: from = state.Position, to = futurePosition. So a collision is detected when from is inside the circle and to is outside. */ if (GeometryHelper.LineCircleIntersection2d(state.Position, futurePosition, circleCenter, circleRadius, intersectionPoint, quadrant)) { collisionFound = true; /* Set the intersection point to slightly before the real intersection point (I read somewhere this was good to do because of floting point precision, not sure exactly how much though). */ intersectionPoint = intersectionPoint - Vector2.NormalizeRet(state.Velocity) * 0.001; /* Normal at the intersection point. */ intersectionPointNormal = Vector2.NormalizeRet(circleCenter - intersectionPoint) } } When I set the intersection point, if I for example use 0.1 instead of 0.001 the puck travels further before it gets stuck, but for all values I have tried (including 0 - the real intersection point) it gets stuck somewhere (but I necessarily not get a stack overflow). Can something in this part be the cause of my problem? I can see why I get the stack overflow when using -1.0 when calculating the new velocity vector; but not how to solve it. I traced the time steps used in the recursion (initial time step is always 1/60 ~ 0.01666): Recursion depth Time step next recursive call [Start recursion, time step ~ 0.016666] 0 0,000985806527246773 [No collision, stop recursion] [Start recursion, time step ~ 0.016666] 0 0,0149596704364629 1 0,0144883449376379 2 0,0143155612984837 3 0,014224925727213 4 0,0141673917461608 5 0,0141265435314026 6 0,0140953966184117 7 0,0140704653746625 ...and so on. As you can see the collision is detected early in every recursive call which means the next time step decreases very slowly thus the recursion depth gets very big - stack overflow.

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  • Changing CSS with jQuery syntax in Silverlight using jLight

    - by Timmy Kokke
    Lately I’ve ran into situations where I had to change elements or had to request a value in the DOM from Silverlight. jLight, which was introduced in an earlier article, can help with that. jQuery offers great ways to change CSS during runtime. Silverlight can access the DOM, but it isn’t as easy as jQuery. All examples shown in this article can be looked at in this online demo. The code can be downloaded here.   Part 1: The easy stuff Selecting and changing properties is pretty straight forward. Setting the text color in all <B> </B> elements can be done using the following code:   jQuery.Select("b").Css("color", "red");   The Css() method is an extension method on jQueryObject which is return by the jQuery.Select() method. The Css() method takes to parameters. The first is the Css style property. All properties used in Css can be entered in this string. The second parameter is the value you want to give the property. In this case the property is “color” and it is changed to “red”. To specify which element you want to select you can add a :selector parameter to the Select() method as shown in the next example.   jQuery.Select("b:first").Css("font-family", "sans-serif");   The “:first” pseudo-class selector selects only the first element. This example changes the “font-family” property of the first <B></B> element to “sans-serif”. To make use of intellisense in Visual Studio I’ve added a extension methods to help with the pseudo-classes. In the example below the “font-weight” of every “Even” <LI></LI> is set to “bold”.   jQuery.Select("li".Even()).Css("font-weight", "bold");   Because the Css() extension method returns a jQueryObject it is possible to chain calls to Css(). The following example show setting the “color”, “background-color” and the “font-size” of all headers in one go.   jQuery.Select(":header").Css("color", "#12FF70") .Css("background-color", "yellow") .Css("font-size", "25px");   Part 2: More complex stuff In only a few cases you need to change only one style property. More often you want to change an entire set op style properties all in one go.  You could chain a lot of Css() methods together. A better way is to add a class to a stylesheet and define all properties in there. With the AddClass() method you can set a style class to a set of elements. This example shows how to add the “demostyle” class to all <B></B> in the document.   jQuery.Select("b").AddClass("demostyle");   Removing the class works in the same way:   jQuery.Select("b").RemoveClass("demostyle");   jLight is build for interacting with to the DOM from Silverlight using jQuery. A jQueryObjectCss object can be used to define different sets of style properties in Silverlight. The over 60 most common Css style properties are defined in the jQueryObjectCss class. A string indexer can be used to access all style properties ( CssObject1[“background-color”] equals CssObject1.BackgroundColor). In the code below, two jQueryObjectCss objects are defined and instantiated.   private jQueryObjectCss CssObject1; private jQueryObjectCss CssObject2;   public Demo2() { CssObject1 = new jQueryObjectCss { BackgroundColor = "Lime", Color="Black", FontSize = "12pt", FontFamily = "sans-serif", FontWeight = "bold", MarginLeft = 150, LineHeight = "28px", Border = "Solid 1px #880000" }; CssObject2 = new jQueryObjectCss { FontStyle = "Italic", FontSize = "48", Color = "#225522" }; InitializeComponent(); }   Now instead of chaining to set all different properties you can just pass one of the jQueryObjectCss objects to the Css() method. In this case all <LI></LI> elements are set to match this object.   jQuery.Select("li").Css(CssObject1); When using the jQueryObjectCss objects chaining is still possible. In the following example all headers are given a blue backgroundcolor and the last is set to match CssObject2.   jQuery.Select(":header").Css(new jQueryObjectCss{BackgroundColor = "Blue"}) .Eq(-1).Css(CssObject2);   Part 3: The fun stuff Having Silverlight call JavaScript and than having JavaScript to call Silverlight requires a lot of plumbing code. Everything has to be registered and strings are passed back and forth to execute the JavaScript. jLight makes this kind of stuff so easy, it becomes fun to use. In a lot of situations jQuery can call a function to decide what to do, setting a style class based on complex expressions for example. jLight can do the same, but the callback methods are defined in Silverlight. This example calls the function() method for each <LI></LI> element. The callback method has to take a jQueryObject, an integer and a string as parameters. In this case jLight differs a bit from the actual jQuery implementation. jQuery uses only the index and the className parameters. A jQueryObject is added to make it simpler to access the attributes and properties of the element. If the text of the listitem starts with a ‘D’ or an ‘M’ the class is set. Otherwise null is returned and nothing happens.   private void button1_Click(object sender, RoutedEventArgs e) { jQuery.Select("li").AddClass(function); }   private string function(jQueryObject obj, int index, string className) { if (obj.Text[0] == 'D' || obj.Text[0] == 'M') return "demostyle"; return null; }   The last thing I would like to demonstrate uses even more Silverlight and less jLight, but demonstrates the power of the combination. Animating a style property using a Storyboard with easing functions. First a dependency property is defined. In this case it is a double named Intensity. By handling the changed event the color is set using jQuery.   public double Intensity { get { return (double)GetValue(IntensityProperty); } set { SetValue(IntensityProperty, value); } }   public static readonly DependencyProperty IntensityProperty = DependencyProperty.Register("Intensity", typeof(double), typeof(Demo3), new PropertyMetadata(0.0, IntensityChanged));   private static void IntensityChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { var i = (byte)(double)e.NewValue; jQuery.Select("span").Css("color", string.Format("#{0:X2}{0:X2}{0:X2}", i)); }   An animation has to be created. This code defines a Storyboard with one keyframe that uses a bounce ease as an easing function. The animation is set to target the Intensity dependency property defined earlier.   private Storyboard CreateAnimation(double value) { Storyboard storyboard = new Storyboard(); var da = new DoubleAnimationUsingKeyFrames(); var d = new EasingDoubleKeyFrame { EasingFunction = new BounceEase(), KeyTime = KeyTime.FromTimeSpan(TimeSpan.FromSeconds(1.0)), Value = value }; da.KeyFrames.Add(d); Storyboard.SetTarget(da, this); Storyboard.SetTargetProperty(da, new PropertyPath(Demo3.IntensityProperty)); storyboard.Children.Add(da); return storyboard; }   Initially the Intensity is set to 128 which results in a gray color. When one of the buttons is pressed, a new animation is created an played. One to animate to black, and one to animate to white.   public Demo3() { InitializeComponent(); Intensity = 128; }   private void button2_Click(object sender, RoutedEventArgs e) { CreateAnimation(255).Begin(); }   private void button3_Click(object sender, RoutedEventArgs e) { CreateAnimation(0).Begin(); }   Conclusion As you can see jLight can make the life of a Silverlight developer a lot easier when accessing the DOM. Almost all jQuery functions that are defined in jLight use the same constructions as described above. I’ve tried to stay as close as possible to the real jQuery. Having JavaScript perform callbacks to Silverlight using jLight will be described in more detail in a future tutorial about AJAX or eventing.

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  • Pet Peeves with the Windows Phone 7 Marketplace

    - by Bil Simser
    Have you ever noticed how something things just gnaw at your very being. This is the case with the WP7 marketplace, the Zune software, and the things that drive me batshit crazy with a side of fries. To go. I wanted to share. XBox Live is Not the Centre of the Universe Okay, it’s fine that the Zune software has an XBox live tag for games so can see them clearly but do we really need to have it shoved down our throats. On every click? Click on Games in the marketplace: The first thing that it defaults to on the filters on the right is XBox Live: Okay. Fine. However if you change it (say to Paid) then click onto a title when you come back from that title is the filter still set to Paid? No. It’s back to XBox Live again. Really? Give us a break. If you change to any filter on any other genre then click on the selected title, it doesn’t revert back to anything. It stays on the selection you picked. Let’s be fair here. The Games genre should behave just like every other one. If I pick Paid then when I come back to the list please remember that. Double Dipping On the subject of XBox Live titles, Microsoft (and developers who have an agreement with Microsoft to produce Live titles, which generally rules out indie game developers) is double dipping with regards to exposure of their titles. Here’s the Puzzle and Trivia Game section on the Marketplace for XBox Live titles: And here’s the same category filtered on Paid titles: See the problem? Two indie titles while the rest are XBox Live ones. So while XBL has it’s filter, they also get to showcase their wares in the Paid and Free filters as well. If you’re going to have an XBox Live filter then use it and stop pushing down indie titles until they’re off the screen (on some genres this is already the case). Free and Paid titles should be just that and not include XBox Live ones. If you’re really stoked that people can’t find the Free XBox Live titles vs. the paid ones, then create a Free XBox Live filter and a Paid XBox Live filter. I don’t think we would mind much. Whose Trial is it Anyways? You might notice apps in the marketplace with titles like “My Fart App Professional Lite” or “Silicon Lamb Spleen Builder Free”. When you submit and app to the marketplace it can either be free or paid. If it’s a paid app you also have the option to submit it with Trial capabilities. It’s up to you to decide what you offer in the trial version but trial versions can be purchased from within the app so after someone trys out your app (for free) and wants to unlock the Super Secret Obama Spy Ring Level, they can just go to the marketplace from your app (if you built that functionality in) and upgrade to the paid version. However it creates a rift of sorts when it comes to visibility. Some developers go the route of the paid app with a trial version, others decide to submit *two* apps instead of one. One app is the “Free” or “Lite” verions and the other is the paid version. Why go to the hassle of submitting two apps when you can just create a trial version in the same app? Again, visibility. There’s no way to tell Paid apps with Trial versions and ones without (it’s an option, you don’t have to provide trial versions, although I think it’s a good idea). However there is a way to see the Free apps from the Paid ones so some submit the two apps and have the Free version have links to buy the paid one (again through the Marketplace tasks in the API). What we as developers need for visibility is a new filter. Trial. That’s it. It would simply filter on Paid apps that have trial capabilities and surface up those apps just like the free ones. If Microsoft added this filter to the marketplace, it would eliminate the need for people to submit their “Free” and “Lite” versions and make it easier for the developer not to have to maintain two systems. I mean, is it really that hard? Can’t be any more difficult than the XBox Live Filter that’s already there. Location is Everything The last thing on my bucket list is about location. When I launch Zune I’m running in my native location setting, Canada. What’s great is that I navigate to the Travel Tools section where I have one of my apps and behold the splendour that I see: There are my apps in the number 1 and number 4 slot for top selling in that category. I show it to my wife to make up for the sleepless nights writing this stuff and we dance around and celebrate. Then I change my location on my operation system to United States and re-launch Zune. WTF? My flight app has slipped to the 10th spot (I’m only showing 4 across here out of the 7 in Zune) and my border check app that was #1 is now in the 32nd spot! End of celebration. Not only is relevance being looked at here, I value the comments people make on may apps as do most developers. I want to respond to them and show them that I’m listening. The next version of my border app will provide multiple camera angles. However when I’m running in my native Canada location, I only see two reviews. Changing over to United States I see fourteen! While there are tools out there to provide with you a unified view, I shouldn’t have to rely on them. My own Zune desktop software should allow me to see everything. I realize that some developers will submit an app and only target it for some locations and that’s their choice. However I shouldn’t have to jump through hoops to see what apps are ahead of mine, or see people comments and ratings. Another proposal. Either unify the marketplace (i.e. when I’m looking at it show me everything combined) or let me choose a filter. I think the first option might be difficult as you’re trying to average out top selling apps across all markets and have to deal with some apps that have been omitted from some markets. Although I think you could come up with a set of use cases that would handle that, maybe that’s too much work. At the very least, let us developers view the markets in a drop down or something from within the Zune desktop. Having to shut down Zune, change our location, and re-launch Zune to see other perspectives is just too onerous. A Call to Action These are just one mans opinion. Do you agree? Disagree? Feel hungry for a bacon sandwich? Let everyone know via the comments below. Perhaps someone from Microsoft will be reading and take some of these ideas under advisement. Maybe not, but at least let’s get the word out that we really want to see some change. Egypt can do it, why not WP7 developers!

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  • Android, how important is deltaTime?

    - by iQue
    Im making a game that is getting pretty big and sometimes my thread has to skip a frame, so far I'm not using deltaTime for setting the speed of my different objects in the game because it's still not a big enough game for it to matter imo. But its getting bigger then I planned, so my question is, how important is delta Time? If I should use delta time there is a problem, since speedX and speedY are integers(they have to be for eclipse to let you make a rectangle of them), I cant add delta time very functionally as far as I understand, but might be wrong? Ive tried adding deltaTime to the code below, and sometimes my enemies just not move after spawn, they just stand there and run in the same place Will add an some code for how I set / use speed: public void update(int dx, int dy) { double theta = 180.0 / Math.PI * Math.atan2(-(y - controls.pointerPosition.y), controls.pointerPosition.x - x); x +=dx * Math.cos(Math.toRadians(theta)); y +=dy * Math.sin(Math.toRadians(theta)); currentFrame = ++currentFrame % BMP_COLUMNS; } public void draw(Canvas canvas) { int srcX = currentFrame * width; int srcY = 1 * height; Rect src = new Rect(srcX, srcY, srcX + width, srcY + height); Rect dst = new Rect(x, y, x + width, y + height); canvas.drawBitmap(bitmap, src, dst, null); } So if someone with some experience with this has any thoughts, please share. Thank you! Changed code: public void update(int dx, int dy, float delta) { double theta = 180.0 / Math.PI * Math.atan2(-(y - controls.pointerPosition.y), controls.pointerPosition.x - x); double speedX = delta * dx * Math.cos(Math.toRadians(theta)); double speedY = delta * dy * Math.sin(Math.toRadians(theta)); x += speedX; y += speedY; currentFrame = ++currentFrame % BMP_COLUMNS; } public void draw(Canvas canvas) { int srcX = currentFrame * width; int srcY = 1 * height; Rect src = new Rect(srcX, srcY, srcX + width, srcY + height); Rect dst = new Rect(x, y, x + width, y + height); canvas.drawBitmap(bitmap, src, dst, null); } with this code my enemies move like before, except they wont move to the right (wont increment x), all other directions work.

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  • 2D Skeletal Animation Transformations

    - by Brad Zeis
    I have been trying to build a 2D skeletal animation system for a while, and I believe that I'm fairly close to finishing. Currently, I have the following data structures: struct Bone { Bone *parent; int child_count; Bone **children; double x, y; }; struct Vertex { double x, y; int bone_count; Bone **bones; double *weights; }; struct Mesh { int vertex_count; Vertex **vertices; Vertex **tex_coords; } Bone->x and Bone->y are the coordinates of the end point of the Bone. The starting point is given by (bone->parent->x, bone->parent->y) or (0, 0). Each entity in the game has a Mesh, and Mesh->vertices is used as the bounding area for the entity. Mesh->tex_coords are texture coordinates. In the entity's update function, the position of the Bone is used to change the coordinates of the Vertices that are bound to it. Currently what I have is: void Mesh_update(Mesh *mesh) { int i, j; double sx, sy; for (i = 0; i < vertex_count; i++) { if (mesh->vertices[i]->bone_count == 0) { continue; } sx, sy = 0; for (j = 0; j < mesh->vertices[i]->bone_count; j++) { sx += (/* ??? */) * mesh->vertices[i]->weights[j]; sy += (/* ??? */) * mesh->vertices[i]->weights[j]; } mesh->vertices[i]->x = sx; mesh->vertices[i]->y = sy; } } I think I have everything I need, I just don't know how to apply the transformations to the final mesh coordinates. What tranformations do I need here? Or is my approach just completely wrong?

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  • Problems building application for Ubuntu App Showdown

    - by Neil Munro
    I have managed to submit my source application to the Ubuntu build servers, however it's not building. This is the build output: https://launchpadlibrarian.net/109592385/buildlog_ubuntu-precise-i386.liberedit_12.07.20_FAILEDTOBUILD.txt.gz I know that there is a dependency on lxml for my application but I don't know how to correct that, but I can also see that it's failing to find my own python modules. I am not sure what is going on in it's entirety here, but I would greatly appreciate getting this to build so I can submit it to the Ubuntu App Showdown. Thanks, Neil

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  • How is precedence determined in C pointers?

    - by ankur.trapasiya
    I've come across two pointer declarations that I'm having trouble understanding. My understanding of precedence rules goes something like this: Operator Precedence Associativity (), [ ] 1 Left to Right *, identifier 2 Right to Left Data type 3 But even given this, I can't seem to figure out how to evaluate the following examples correctly: First example float * (* (*ptr)(int))(double **,char c) My evaluation: *(ptr) (int) *(*ptr)(int) *(*(*ptr)(int)) Then, double ** char c Second example unsigned **( * (*ptr) [5] ) (char const *,int *) *(ptr) [5] *(*ptr)[5] *(*(*ptr)[5]) **(*(*ptr)[5]) How should I read them?

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  • Finding Z given X & Y coordinates on terrain?

    - by mrky
    I need to know what the most efficient way of finding Z given X & Y coordinates on terrain. My terrain is set up as a grid, each grid block consisting of two triangles, which may be flipped in any direction. I want to move game objects smoothly along the floor of the terrain without "stepping." I'm currently using the following method with unexpected results: double mapClass::getZ(double x, double y) { int vertexIndex = ((floor(y))*width*2)+((floor(x))*2); vec3ray ray = {glm::vec3(x, y, 2), glm::vec3(x, y, 0)}; vec3triangle tri1 = { glmFrom(vertices[vertexIndex].v1), glmFrom(vertices[vertexIndex].v2), glmFrom(vertices[vertexIndex].v3) }; vec3triangle tri2 = { glmFrom(vertices[vertexIndex+1].v1), glmFrom(vertices[vertexIndex+1].v2), glmFrom(vertices[vertexIndex+1].v3) }; glm::vec3 intersect; if (!intersectRayTriangle(tri1, ray, intersect)) { intersectRayTriangle(tri2, ray, intersect); } return intersect.z; } intersectRayTriangle() and glmFrom() are as follows: bool intersectRayTriangle(vec3triangle tri, vec3ray ray, glm::vec3 &worldIntersect) { glm::vec3 barycentricIntersect; if (glm::intersectLineTriangle(ray.origin, ray.direction, tri.p0, tri.p1, tri.p2, barycentricIntersect)) { // Convert barycentric to world coordinates double u, v, w; u = barycentricIntersect.x; v = barycentricIntersect.y; w = 1 - (u+v); worldIntersect.x = (u * tri.p0.x + v * tri.p1.x + w * tri.p2.x); worldIntersect.y = (u * tri.p0.y + v * tri.p1.y + w * tri.p2.y); worldIntersect.z = (u * tri.p0.z + v * tri.p1.z + w * tri.p2.z); return true; } else { return false; } } glm::vec3 glmFrom(s_point3f point) { return glm::vec3(point.x, point.y, point.z); } My convenience structures are defined as: struct s_point3f { GLfloat x, y, z; }; struct s_triangle3f { s_point3f v1, v2, v3; }; struct vec3ray { glm::vec3 origin, direction; }; struct vec3triangle { glm::vec3 p0, p1, p2; }; vertices is defined as: std::vector<s_triangle3f> vertices; Basically, I'm trying to get the intersect of a ray (which is positioned at the x, and y coordinates specified facing pointing downwards toward the terrain) and one of the two triangles on the grid. getZ() rarely returns anything but 0. Other times, the numbers it generates seem to be completely off. Am I taking the wrong approach? Can anyone see a problem with my code? Any help or critique is appreciated!

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  • SQL SERVER Find Max Worker Count using DMV 32 Bit and 64 Bit

    During several recent training courses, I found it very interesting that Worker Thread is not quite known to everyone despite the fact that it is a very important feature. At some point in the discussion, one of the attendees mentioned that we can double the Worker Thread if we double the CPU (add the same [...]...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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