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  • Astar implementation in AS3

    - by Bryan Hare
    Hey, I am putting together a project for a class that requires me to put AI in a top down Tactical Strategy game in Flash AS3. I decided that I would use a node based path finding approach because the game is based on a circular movement scheme. When a player moves a unit he essentially draws a series of line segments that connect that a player unit will follow along. I am trying to put together a similar operation for the AI units in our game by creating a list of nodes to traverse to a target node. Hence my use of Astar (the resulting path can be used to create this line). Here is my Algorithm function findShortestPath (startN:node, goalN:node) { var openSet:Array = new Array(); var closedSet:Array = new Array(); var pathFound:Boolean = false; startN.g_score = 0; startN.h_score = distFunction(startN,goalN); startN.f_score = startN.h_score; startN.fromNode = null; openSet.push (startN); var i:int = 0 for(i= 0; i< nodeArray.length; i++) { for(var j:int =0; j<nodeArray[0].length; j++) { if(!nodeArray[i][j].isPathable) { closedSet.push(nodeArray[i][j]); } } } while (openSet.length != 0) { var cNode:node = openSet.shift(); if (cNode == goalN) { resolvePath (cNode); return true; } closedSet.push (cNode); for (i= 0; i < cNode.dirArray.length; i++) { var neighborNode:node = cNode.nodeArray[cNode.dirArray[i]]; if (!(closedSet.indexOf(neighborNode) == -1)) { continue; } neighborNode.fromNode = cNode; var tenativeg_score:Number = cNode.gscore + distFunction(neighborNode.fromNode,neighborNode); if (openSet.indexOf(neighborNode) == -1) { neighborNode.g_score = neighborNode.fromNode.g_score + distFunction(neighborNode,cNode); if (cNode.dirArray[i] >= 4) { neighborNode.g_score -= 4; } neighborNode.h_score=distFunction(neighborNode,goalN); neighborNode.f_score=neighborNode.g_score+neighborNode.h_score; insertIntoPQ (neighborNode, openSet); //trace(" F Score of neighbor: " + neighborNode.f_score + " H score of Neighbor: " + neighborNode.h_score + " G_score or neighbor: " +neighborNode.g_score); } else if (tenativeg_score <= neighborNode.g_score) { neighborNode.fromNode=cNode; neighborNode.g_score=cNode.g_score+distFunction(neighborNode,cNode); if (cNode.dirArray[i]>=4) { neighborNode.g_score-=4; } neighborNode.f_score=neighborNode.g_score+neighborNode.h_score; openSet.splice (openSet.indexOf(neighborNode),1); //trace(" F Score of neighbor: " + neighborNode.f_score + " H score of Neighbor: " + neighborNode.h_score + " G_score or neighbor: " +neighborNode.g_score); insertIntoPQ (neighborNode, openSet); } } } trace ("fail"); return false; } Right now this function creates paths that are often not optimal or wholly inaccurate given the target and this generally happens when I have nodes that are not path able, and I am not quite sure what I am doing wrong right now. If someone could help me correct this I would appreciate it greatly. Some Notes My OpenSet is essentially a Priority Queue, so thats how I sort my nodes by cost. Here is that function function insertIntoPQ (iNode:node, pq:Array) { var inserted:Boolean=true; var iterater:int=0; while (inserted) { if (iterater==pq.length) { pq.push (iNode); inserted=false; } else if (pq[iterater].f_score >= iNode.f_score) { pq.splice (iterater,0,iNode); inserted=false; } ++iterater; } } Thanks!

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  • Grid pathfinding with a lot of entities

    - by Vee
    I'd like to explain this problem with a screenshot from a released game, DROD: Gunthro's Epic Blunder, by Caravel Games. The game is turn-based and tile-based. I'm trying to create something very similar (a clone of the game), and I've got most of the fundamentals done, but I'm having trouble implementing pathfinding. Look at the screenshot. The guys in yellow are friendly, and want to kill the roaches. Every turn, every guy in yellow pathfinds to the closest roach, and every roach pathfinds to the closest guy in yellow. By closest I mean the target with the shortest path, not a simple distance calculation. All of this without any kind of slowdown when loading the level or when passing turns. And all of the entities change position every turn. Also (not shown in screenshot), there can be doors that open and close and change the level's layout. Impressive. I've tried implementing pathfinding in my clone. First attempt was making every roach find a path to a yellow guy every turn, using a breadth-first search algorithm. Obviously incredibly slow with more than a single roach, and would get exponentially slower with more than a single yellow guy. Second attempt was mas making every yellow guy generate a pathmap (still breadth-first search) every time he moved. Worked perfectly with multiple roaches and a single yellow guy, but adding more yellow guys made the game slow and unplayable. Last attempt was implementing JPS (jump point search). Every entity would individually calculate a path to its target. Fast, but with a limited number of entities. Having less than half the entities in the screenshot would make the game slow. And also, I had to get the "closest" enemy by calculating distance, not shortest path. I've asked on the DROD forums how they did it, and a user replied that it was breadth-first search. The game is open source, and I took a look at the source code, but it's C++ (I'm using C#) and I found it confusing. I don't know how to do it. Every approach I tried isn't good enough. And I believe that DROD generates global pathmaps, somehow, but I can't understand how every entity find the best individual path to other entities that move every turn. What's the trick? This is a reply I just got on the DROD forums: Without having looked at the code I'd wager it's two (or so) pathmaps for the whole room: One to the nearest enemy, and one to the nearest friendly for every tile. There's no need to make a separate pathmap for every entity when the overall goal is "move towards nearest enemy/friendly"... just mark every tile with the number of moves it takes to the nearest target and have the entity chose the move that takes it to the tile with the lowest number. To be honest, I don't understand it that well.

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  • A* algorithm very slow

    - by Amaranth
    I have an programming a RTS game (I use XNA with C#). The pathfinding is working fine, except that when it has a lot of node to search in, there is a lag period of one or two seconds, it happens mainly when there is no path to the target destination, since it that situation there is more nodes to explore. I have the same problem when the path is shorter but selected more than 3 units (can't take the same path since the selected units can be in different part of the map). private List<NodeInfo> FindPath(Unit u, NodeInfo start, NodeInfo end) { Map map = GameInfo.GetInstance().GameMap; _nearestToTarget = start; start.MoveCost = 0; Vector2 endPosition = map.getTileByPos(end.X, end.Y).Position; //getTileByPos simply gets the tile in a 2D array with the X and Y indexes start.EstimatedRemainingCost = (int)(endPosition - map.getTileByPos(start.X, start.Y).Position).Length(); start.Parent = null; List<NodeInfo> openedNodes = new List<NodeInfo>(); ; List<NodeInfo> closedNodes = new List<NodeInfo>(); Point[] movements = GetMovements(u.UnitType); openedNodes.Add(start); while (!closedNodes.Contains(end) && openedNodes.Count > 0) { //Loop in nodes to find lowest cost NodeInfo currentNode = FindLowestCostOpenedNode(openedNodes); openedNodes.Remove(currentNode); closedNodes.Add(currentNode); Vector2 previousMouvement; if (currentNode.Parent == null) { previousMouvement = ConvertRotationToDirectionVector(u.Rotation); } else { previousMouvement = map.getTileByPos(currentNode.X, currentNode.Y).Position - map.getTileByPos(currentNode.Parent.X, currentNode.Parent.Y).Position; previousMouvement.Normalize(); } //For each neighbor foreach (Point movement in movements) { Point exploredGridPos = new Point(currentNode.X + movement.X, currentNode.Y + movement.Y); //Checks if valid move and checks if not if closed nodes list if (ValidNavigableNode(u.UnitType, new Point(currentNode.X, currentNode.Y), exploredGridPos) && !closedNodes.Contains(_gridMap[exploredGridPos.Y, exploredGridPos.X])) { NodeInfo exploredNode = _gridMap[exploredGridPos.Y, exploredGridPos.X]; Tile.TileType exploredTerrain = map.getTileByPos(exploredGridPos.X, exploredGridPos.Y).TerrainType; if(openedNodes.Contains(exploredNode)) { int newCost = currentNode.MoveCost + GetMoveCost(previousMouvement, movement, exploredTerrain); if (newCost < exploredNode.MoveCost) { exploredNode.Parent = currentNode; exploredNode.MoveCost = newCost; //Find nearest tile to the target (in case doesn't find path to target) //Only compares the node to the current nearest FindNearest(exploredNode); } } else { exploredNode.Parent = currentNode; exploredNode.MoveCost = currentNode.MoveCost + GetMoveCost(previousMouvement, movement, exploredTerrain); Vector2 exploredNodeWorldPos = map.getTileByPos(exploredGridPos.X, exploredGridPos.Y).Position; exploredNode.EstimatedRemainingCost = (int)(endPosition - exploredNodeWorldPos).Length(); //Find nearest tile to the target (in case doesn't find path to target) //Only compares the node to the current nearest FindNearest(exploredNode); openedNodes.Add(exploredNode); } } } } return closedNodes; } After that, I simply check if the end node is contained in the returned nodes. If so, I add the end node and each parent until I reach the start. If not, I add the nearestToTarget and each parent until I reach the start. I added a condition before calling FindPath so that only one unit can call a find path each frame (60 frame per second), but it makes no difference. I thought maybe I could solve this by allowing the find path to run in background while the game continues to run correctly, even if it takes a few frame (it is currently sequential sonce it is called in the update() of the unit if there's a target location but no path), but I don't really know how... I also though about sorting my opened nodes list by cost so I don't have to loop them, but I don't know if that would have an effect on the performance... Would there be other solutions? P.S. In the code, when I get the Move Cost, I check if the unit has to turn to perform the move, and the terrain type, nothing hard to do.

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  • MacBook (13 in. Aluminum late 08) power adapter starting to fail

    - by Mr. Man
    I have a MacBook (Late '08 13 In. Aluminum) with the Apple provided power adapter. I think it may be failing because It takes a little moving around with the cable nearest where it connects to the MacBook to get it to charge (small light turns on). The area of cable nearest the MacBook gets very hot, almost burning. Any ideas of how I could fix it? Hopefully without replacing the adapter. Thanks in advance!

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  • glTexParameter and filtering in OpenGL and GLSL?

    - by sharoz
    I have a couple questions about glTexParameter and filtering 1) What is the scope when applying a glTexParameter (specifically the filtering)? Here's a scenario: Bind a texture. Set the filters to LINEAR Set the texture to "Sampler1" of a shader Bind another texture. Set its filters to NEAREST Set that texture to "Sampler2" of a shader Draw When I use the textures in a shader, will one be linear and the other be nearest? Or will they both be nearest because it was called last? 2) Is it possible to set the filtering method in GLSL? Thanks in advance!

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  • Roundoff Timespan to 15 min interval

    - by s-a-n
    I have a property in my code where users can enter a timespan in HH:mm like 10:32 10:44 15:45 I want to round off in my property to the nearest 15mins but i dont have datetime here. I only need to do it with Timespan 10:32 to 10:30 10:44 to 10:45 15:45 to 15:45 01:02 to 01:00 02:11 to 02:15 03:22 to 03:25 23:52 to 00:00 Tried all these solutions but they involve Datetime in them How can I round up the time to the nearest X minutes? Is there a simple function for rounding a DateTime down to the nearest 30 minutes, in C#? DotNet Roundoff datetime to last 15 minutes

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  • Erratic WiFi 2.4 GHz channel spikes, what gives?

    - by Francis W. Usher
    Sorry guys, first a gripe about my neighbor's WiFi access point (it is related): they totally hog the center nine 2.4 GHz channels (3-11), centered right at 7! I know the outer regions of the signal don't make as much of a difference, and technically they're running channels 5 & 9. Anyway, their signal is clearly interfering with mine, which is necessarily centered at 3 or 11 to evade their interference. I guess it's somewhat a case of access point envy: they happen to have both a stronger signal and a higher data rate, while occupying twice the band width that I do. Getting to the point, I've noticed that they tend to sit nice and pretty centered at 7, but they definitely auto-select their channel, and I've noticed that the auto-selection algorithm tends to shift towards the higher channels; hence I decided to pick channel 3, and I don't get so many intermittent lag spikes any more. Anyway, the thing that weirded me out was the reason they have to auto-select sometimes: unexplained, powerful (talking order of 0dB here), giant spikes of 2.4 GHz activity in consistent regions of the spectrum. I don't think it's just noise, since my wireless monitoring software is registering a MAC address, a manufacturer, and usually a fairly coherent ascii name... and it seems to be a fairly well-confined signal. But these signals are fairly common, and they do some weird stuff to my signal. So my question is what are these signals? Where are they coming from? Where are they going? Why are they so ridiculously strong? Why don't they ever last very long? Here's an inSSIDer screenshot I took, for your perusal. I am labeled with "me", my greedy neighbor labeled with "neighbor", and the 2 quasar signals are labeled with "WTF?".

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  • Why distance field text rendering have clear outline?

    - by jinhwan
    http://www.valvesoftware.com/publications/2007/SIGGRAPH2007_AlphaTestedMagnification.pdf All the process for doing distance rendering is clear, but 'how does it work' is not clear for me. It looks like that distance field pixels which are created around original pixel may affect 2d texture sampling interpolation process. But I can't understand the interpolation process. I've read that the distance field rendering is processed under nearest-neighbour interpolation. If it is true, shouldn't the distance field redering creates non interpolated result? In my thought, they should looks liked retro style pixel art. Where do i misunderstand in this process? So far, It is no difference with alpha test for me. Both of them throw away all pixcel which are not in. How does extra distance field pixel affect rendering under nearest-neighbour interpolation?

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  • Name attribute is obsolete, what is the correct behavior when dealing with anchors?

    - by Tchalvak
    Putting some code through the html5 validator, I get this: Warning: The name attribute on the a element is obsolete. Consider putting an id attribute on the nearest container instead. I find that unclear. Is the "nearest container" for an anchor link the a itself, so that the correct code would be <a id='blah'> instead of <a name='blah'>? Or are empty placeholder <a> tags as a whole deprecated, and anchors can simply point to any element with an id instead?

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  • Dependency between operations in scala actors

    - by paradigmatic
    I am trying to parallelise a code using scala actors. That is my first real code with actors, but I have some experience with Java Mulithreading and MPI in C. However I am completely lost. The workflow I want to realise is a circular pipeline and can be described as the following: Each worker actor has a reference to another one, thus forming a circle There is a coordinator actor which can trigger a computation by sending a StartWork() message When a worker receives a StartWork() message, it process some stuff locally and sends DoWork(...) message to its neighbour in the circle. The neighbours do some other stuff and sends in turn a DoWork(...) message to its own neighbour. This continues until the initial worker receives a DoWork() message. The coordinator can send a GetResult() message to the initial worker and wait for a reply. The point is that the coordinator should only receive a result when data is ready. How can a worker wait that the job returned to it before answering the GetResult() message ? To speed up computation, any worker can receive a StartWork() at any time. Here is my first try pseudo-implementation of the worker: class Worker( neighbor: Worker, numWorkers: Int ) { var ready = Foo() def act() { case StartWork() => { val someData = doStuff() neighbor ! DoWork( someData, numWorkers-1 ) } case DoWork( resultData, remaining ) => if( remaining == 0 ) { ready = resultData } else { val someOtherData = doOtherStuff( resultData ) neighbor ! DoWork( someOtherData, remaining-1 ) } case GetResult() => reply( ready ) } } On the coordinator side: worker ! StartWork() val result = worker !? GetResult() // should wait

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  • Loadbalancing outbound traffic while using openbgpd on freebsd

    - by Rajkumar S
    Hi, I am using openbgpd in freeBSD with 2 ISP connections. I have my own AS number and a /22 network. Currently I am advertising entire /22 to both networks. Inbound traffic comes in But my outbound traffic goes via a single link. I would like to either distribute my outbound traffic via both links so that outbound traffic is also load balanced. How to configure this using openbgpd in freebsd? My current openbgpd config is attached for reference. AS 00my-as listen on xx.xx.xx.x router-id xx.xx.xx.x network aa.aa.aa.0/22 group "ISP1" { remote-as 11remoteas-1 neighbor bb.bb.bb.1 { descr "ISP1" announce all } } group "ISP2" { remote-as 22remoteas-2 neighbor cc.cc.cc.37 { descr "ISP2" announce all } } deny from any deny to any allow from bb.bb.bb.1 allow to bb.bb.bb.1 allow from cc.cc.cc.37 allow to cc.cc.cc.37

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  • I believe I need a wireless access point, but can I do it with a wifi router?

    - by Flotsam N. Jetsam
    My needs are simple, I think: I have a laptop upstairs with a usb wifi that I use to connect to my neighbor's wifi which I share (with their knowledge). I have a laser printer downstairs that my wife doesn't wants to stay down there (big, bulky and ugly), but that we both need to print stuff off. It has wired networking and I have wired hub and router down there. The usb wifi on the laptop has absolutley the best reception I've ever seen or heard of. I cannot get onto the neighbor's net with the thing downstairs though--sortof in the ground. What do I need downstairs to give printer access to my laptop wirelessly? One thing I can't do in this solution is have a computer on downstairs, so I would think that would eliminate a usb solution.

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  • Data Structure for Small Number of Agents in a Relatively Big 2D World

    - by Seçkin Savasçi
    I'm working on a project where we will implement a kind of world simulation where there is a square 2D world. Agents live on this world and make decisions like moving or replicating themselves based on their neighbor cells(world=grid) and some extra parameters(which are not based on the state of the world). I'm looking for a data structure to implement such a project. My concerns are : I will implement this 3 times: sequential, using OpenMP, using MPI. So if I can use the same structure that will be quite good. The first thing comes up is keeping a 2D array for the world and storing agent references in it. And simulate the world for each time slice by checking every cell in each iteration and further processing if an agents is found in the cell. The downside is what if I have 1000x1000 world and only 5 agents in it. It will be an overkill for both sequential and parallel versions to check each cell and look for possible agents in them. I can use quadtree and store agents in it, but then how can I get the information about neighbor cells then? Please let me know if I should elaborate more.

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  • C# rounding DateTime objects

    - by grenade
    I want to round dates/times to the nearest interval for a charting application. I'd like an extension method signature like follows so that the rounding can be acheived for any level of accuracy: static DateTime Round(this DateTime date, TimeSpan span); The idea is that if I pass in a timespan of ten minutes, it will round to the nearest ten minute interval. I can't get my head around the implementation and am hoping one of you will have written or used something similar before. I think either a floor, ceiling or nearest implementation is fine. Any ideas? Edit: Thanks to @tvanfosson & @ShuggyCoUk, the implementation looks like this: public static class DateExtensions { public static DateTime Round(this DateTime date, TimeSpan span) { long ticks = (date.Ticks / span.Ticks) + (span.Ticks / 2) + 1; return new DateTime(ticks * span.Ticks); } public static DateTime Floor(this DateTime date, TimeSpan span) { long ticks = (date.Ticks / span.Ticks); return new DateTime(ticks * span.Ticks); } public static DateTime Ceil(this DateTime date, TimeSpan span) { long ticks = (date.Ticks + span.Ticks - 1) / span.Ticks; return new DateTime(ticks * span.Ticks); } } And is called like so: DateTime nearestHour = DateTime.Now.Round(new TimeSpan(1,0,0)); DateTime minuteCeiling = DateTime.Now.Ceil(new TimeSpan(0,1,0)); DateTime weekFloor = DateTime.Now.Floor(new TimeSpan(7,0,0,0)); ... Cheers!

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  • Finding distance to the closest point in a point cloud on an uniform grid

    - by erik
    I have a 3D grid of size AxBxC with equal distance, d, between the points in the grid. Given a number of points, what is the best way of finding the distance to the closest point for each grid point (Every grid point should contain the distance to the closest point in the point cloud) given the assumptions below? Assume that A, B and C are quite big in relation to d, giving a grid of maybe 500x500x500 and that there will be around 1 million points. Also assume that if the distance to the nearest point exceds a distance of D, we do not care about the nearest point distance, and it can safely be set to some large number (D is maybe 2 to 10 times d) Since there will be a great number of grid points and points to search from, a simple exhaustive: for each grid point: for each point: if distance between points < minDistance: minDistance = distance between points is not a good alternative. I was thinking of doing something along the lines of: create a container of size A*B*C where each element holds a container of points for each point: define indexX = round((point position x - grid min position x)/d) // same for y and z add the point to the correct index of the container for each grid point: search the container of that grid point and find the closest point if no points in container and D > 0.5d: search the 26 container indices nearest to the grid point for a closest point .. continue with next layer until a point is found or the distance to that layer is greater than D Basically: put the points in buckets and do a radial search outwards until a points is found for each grid point. Is this a good way of solving the problem, or are there better/faster ways? A solution which is good for parallelisation is preferred.

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  • PHP - Database schema: version control, branching, migrations.

    - by Billiam
    I'm trying to come up with (or find) a reusable system for database schema versioning in php projects. There are a number of Rails-style migration projects available for php. http://code.google.com/p/mysql-php-migrations/ is a good example. It uses timestamps for migration files, which helps with conflicts between branches. General problem with this kind of system: When development branch A is checked out, and you want to check out branch B instead, B may have new migration files. This is fine, migrating to newer content is straight forward. If branch A has newer migration files, you would need to migrate downwards to the nearest shared patch. If branch A and B have significantly different code bases, you may have to migrate down even further. This may mean: Check out B, determine shared patch number, check out A, migrate downwards to this patch. This must be done from A since the actual applied patches are not available in B. Then, checkout branch B, and migrate to newest B patch. Reverse process again when going from B to A. Proposed system: When migrating upwards, instead of just storing the patch version, serialize the whole patch in database for later use, though I'd probably only need the down() method. When changing branches, compare patches that have been run to patches that are available in the destination branch. Determine nearest shared patch (or oldest difference, maybe) between db table of run patches and patches in destination branch by ID or hash. Could also look for new or missing patches that are buried under a number of shared patches between the two branches. Automatically merge down to the nearest shared patch, using the db table stored down() methods, and then merge up to the branche's latest patch. My question is: Is this system too crazy and/or fraught with consequences to bother developing? My experience with database schema versioning is limited to PHP autopatch, which is an up()-only system requiring filenames with sequential IDs.

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  • Specific cron at time point [closed]

    - by ARTI
    I have a very specific task, but can't handle it. I am not a programmer and totally n00b on bash scritps. So the question is, how to create a cron job like this: Script A.sh could be called at any time by hands, and it should create cron job to run script B.sh once at the nearest time point. For example I will have 4 time points: 10.00pm, 10.15pm, 10.30pm, 10.45pm. So if trigger a script A.sh at 10.07pm it should creat cron job to run ONCE script B.sh at 10.15h, because 10.15h is the nearest time point in future. Is it possible? How can I write such script A.sh? I use Centos 6 It is very important and urgent for me. Thank you very much.

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  • Help on TileMapRenderer

    - by Crypted
    In my project, I'm trying to render a map using TileMapRenderer. But it doesn't show anything when I render it. But when I use some other files from a tutorial they are rendered correctly. When debugging my TileAtlas instance shows the size as 0. I have used Texture Packer UI for packing the images. Comparing with the tutorial's files, I can see that the index starts from 1 in my file and 0 in the tutorial. But changing it to 0 wouldn't work also. map.png format: RGBA8888 filter: Nearest,Nearest repeat: none Map rotate: false xy: 0, 0 size: 32, 32 orig: 32, 32 offset: 0, 0 index: 1 Map rotate: false xy: 32, 0 size: 32, 32 orig: 32, 32 offset: 0, 0 index: 2 Map rotate: false xy: 64, 0 size: 32, 32 orig: 32, 32 offset: 0, 0 index: 3 Map rotate: false xy: 96, 0 size: 32, 32 orig: 32, 32 offset: 0, 0 index: 4 Map rotate: false xy: 128, 0 size: 32, 32 orig: 32, 32 offset: 0, 0 index: 5 Here is the begining of the tmx file. <?xml version="1.0" encoding="UTF-8"?> <map version="1.0" orientation="orthogonal" width="20" height="20" tilewidth="32" tileheight="32"> <tileset firstgid="1" name="a" tilewidth="32" tileheight="32"> <image source="map.png" width="256" height="32"/> </tileset> <layer name="Tile Layer 1" width="20" height="20"> <data> <tile gid="2"/> <tile gid="2"/> Apart from that the tutorial files and my files seems to be similar. Can anyone help me here.

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  • Mesh with Alpha Texture doesn't blend properly

    - by faulty
    I've followed example from various place regarding setting OutputMerger's BlendState to enable alpha/transparent texture on mesh. The setup is as follows: var transParentOp = new BlendStateDescription { SourceBlend = BlendOption.SourceAlpha, DestinationBlend = BlendOption.InverseDestinationAlpha, BlendOperation = BlendOperation.Add, SourceAlphaBlend = BlendOption.Zero, DestinationAlphaBlend = BlendOption.Zero, AlphaBlendOperation = BlendOperation.Add, }; I've made up a sample that display 3 mesh A, B and C, where each overlaps one another. They are drawn sequentially, A to C. Distance from camera where A is nearest and C is furthest. So, the expected output is that A see through and saw part of B and C. B will see through and saw part of C. But what I get was none of them see through in that order, but if I move C closer to the camera, then it will be semi transparent and see through A and B. B if move closer to camera will see A but not C. Sort of reverse. So it seems that I need to draw them in reverse order where furthest from camera is drawn first then nearest to camera is drawn last. Is it suppose to be done this way, or I can actually configure the blendstate so it works no matter in which order i draw them? Thanks

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  • OpenGL depth texture wrong

    - by CoffeeandCode
    I have been writing a game engine for a while now and have decided to reconstruct my positions from depth... but how I read the depth seems to be wrong :/ What is wrong in my rendering? How I init my depth texture in the FBO gl::BindTexture(gl::TEXTURE_2D, this->textures[0]); // Depth gl::TexImage2D( gl::TEXTURE_2D, 0, gl::DEPTH32F_STENCIL8, width, height, 0, gl::DEPTH_STENCIL, gl::FLOAT_32_UNSIGNED_INT_24_8_REV, nullptr ); gl::TexParameterf(gl::TEXTURE_2D, gl::TEXTURE_MAG_FILTER, gl::NEAREST); gl::TexParameterf(gl::TEXTURE_2D, gl::TEXTURE_MIN_FILTER, gl::NEAREST); gl::TexParameterf(gl::TEXTURE_2D, gl::TEXTURE_WRAP_S, gl::CLAMP_TO_EDGE); gl::TexParameterf(gl::TEXTURE_2D, gl::TEXTURE_WRAP_T, gl::CLAMP_TO_EDGE); gl::FramebufferTexture2D( gl::FRAMEBUFFER, gl::DEPTH_STENCIL_ATTACHMENT, gl::TEXTURE_2D, this->textures[0], 0 ); Linear depth readings in my shader Vertex #version 150 layout(location = 0) in vec3 position; layout(location = 1) in vec2 uv; out vec2 uv_f; void main(){ uv_f = uv; gl_Position = vec4(position, 1.0); } Fragment (where the issue probably is) #version 150\n uniform sampler2D depth_texture; in vec2 uv_f; out vec4 Screen; void main(){ float n = 0.00001; float f = 100.0; float z = texture(depth_texture, uv_f).x; float linear_depth = (n * z)/(f - z * (f - n)); Screen = vec4(linear_depth); // It ISN'T because I don't separate alpha } When Rendered so gamedev.stackexchange, what's wrong with my rendering/glsl?

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  • All possible combinations of length 8 in a 2d array

    - by CodeJunki
    Hi, I've been trying to solve a problem in combinations. I have a matrix 6X6 i'm trying to find all combinations of length 8 in the matrix. I have to move from neighbor to neighbor form each row,column position and i wrote a recursive program which generates the combination but the problem is it generates a lot of duplicates as well and hence is inefficient. I would like to know how could i eliminate calculating duplicates and save time. int a={{1,2,3,4,5,6}, {8,9,1,2,3,4}, {5,6,7,8,9,1}, {2,3,4,5,6,7}, {8,9,1,2,3,4}, {5,6,7,8,9,1}, } void genSeq(int row,int col,int length,int combi) { if(length==8) { printf("%d\n",combi); return; } combi = (combi * 10) + a[row][col]; if((row-1)>=0) genSeq(row-1,col,length+1,combi); if((col-1)>=0) genSeq(row,col-1,length+1,combi); if((row+1)<6) genSeq(row+1,col,length+1,combi); if((col+1)<6) genSeq(row,col+1,length+1,combi); if((row+1)<6&&(col+1)<6) genSeq(row+1,col+1,length+1,combi); if((row-1)>=0&&(col+1)<6) genSeq(row-1,col+1,length+1,combi); if((row+1)<6&&(row-1)>=0) genSeq(row+1,col-1,length+1,combi); if((row-1)>=0&&(col-1)>=0) genSeq(row-1,col-1,length+1,combi); } I was also thinking of writing a dynamic program basically recursion with memorization. Is it a better choice?? if yes than I'm not clear how to implement it in recursion. Have i really hit a dead end with approach??? Thankyou Edit Eg result 12121212,12121218,12121219,12121211,12121213. the restrictions are that you have to move to your neighbor from any point, you have to start for each position in the matrix i.e each row,col. you can move one step at a time, i.e right, left, up, down and the both diagonal positions. Check the if conditions. i.e if your in (0,0) you can move to either (1,0) or (1,1) or (0,1) i.e three neighbors. if your in (2,2) you can move to eight neighbors. so on...

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  • Linux - Only first virtual interface can ping external gateway

    - by husvar
    I created 3 virtual interfaces with different mac addresses all linked to the same physical interface. I see that they successfully arp for the gw and they can ping (the request is coming in the packet capture in wireshark). However the ping utility does not count the responses. Does anyone knows the issue? I am running Ubuntu 14.04 in a VmWare. root@ubuntu:~# ip link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff inet6 fe80::20c:29ff:febc:fc8b/64 scope link valid_lft forever preferred_lft forever root@ubuntu:~# ip route sh root@ubuntu:~# ip link add link eth0 eth0.1 addr 00:00:00:00:00:11 type macvlan root@ubuntu:~# ip link add link eth0 eth0.2 addr 00:00:00:00:00:22 type macvlan root@ubuntu:~# ip link add link eth0 eth0.3 addr 00:00:00:00:00:33 type macvlan root@ubuntu:~# ip -4 link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff 18: eth0.1@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:11 brd ff:ff:ff:ff:ff:ff 19: eth0.2@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:22 brd ff:ff:ff:ff:ff:ff 20: eth0.3@eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default link/ether 00:00:00:00:00:33 brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip -4 addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever root@ubuntu:~# ip -4 route sh root@ubuntu:~# dhclient -v eth0.1 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.1/00:00:00:00:00:11 Sending on LPF/eth0.1/00:00:00:00:00:11 Sending on Socket/fallback DHCPDISCOVER on eth0.1 to 255.255.255.255 port 67 interval 3 (xid=0x568eac05) DHCPREQUEST of 192.168.1.145 on eth0.1 to 255.255.255.255 port 67 (xid=0x568eac05) DHCPOFFER of 192.168.1.145 from 192.168.1.254 DHCPACK of 192.168.1.145 from 192.168.1.254 bound to 192.168.1.145 -- renewal in 1473 seconds. root@ubuntu:~# dhclient -v eth0.2 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.2/00:00:00:00:00:22 Sending on LPF/eth0.2/00:00:00:00:00:22 Sending on Socket/fallback DHCPDISCOVER on eth0.2 to 255.255.255.255 port 67 interval 3 (xid=0x21e3114e) DHCPREQUEST of 192.168.1.146 on eth0.2 to 255.255.255.255 port 67 (xid=0x21e3114e) DHCPOFFER of 192.168.1.146 from 192.168.1.254 DHCPACK of 192.168.1.146 from 192.168.1.254 bound to 192.168.1.146 -- renewal in 1366 seconds. root@ubuntu:~# dhclient -v eth0.3 Internet Systems Consortium DHCP Client 4.2.4 Copyright 2004-2012 Internet Systems Consortium. All rights reserved. For info, please visit https://www.isc.org/software/dhcp/ Listening on LPF/eth0.3/00:00:00:00:00:33 Sending on LPF/eth0.3/00:00:00:00:00:33 Sending on Socket/fallback DHCPDISCOVER on eth0.3 to 255.255.255.255 port 67 interval 3 (xid=0x11dc5f03) DHCPREQUEST of 192.168.1.147 on eth0.3 to 255.255.255.255 port 67 (xid=0x11dc5f03) DHCPOFFER of 192.168.1.147 from 192.168.1.254 DHCPACK of 192.168.1.147 from 192.168.1.254 bound to 192.168.1.147 -- renewal in 1657 seconds. root@ubuntu:~# ip -4 link sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP mode DEFAULT group default qlen 1000 link/ether 00:0c:29:bc:fc:8b brd ff:ff:ff:ff:ff:ff 18: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:11 brd ff:ff:ff:ff:ff:ff 19: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:22 brd ff:ff:ff:ff:ff:ff 20: eth0.3@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN mode DEFAULT group default link/ether 00:00:00:00:00:33 brd ff:ff:ff:ff:ff:ff root@ubuntu:~# ip -4 addr sh 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever 18: eth0.1@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.145/24 brd 192.168.1.255 scope global eth0.1 valid_lft forever preferred_lft forever 19: eth0.2@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.146/24 brd 192.168.1.255 scope global eth0.2 valid_lft forever preferred_lft forever 20: eth0.3@eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN group default inet 192.168.1.147/24 brd 192.168.1.255 scope global eth0.3 valid_lft forever preferred_lft forever root@ubuntu:~# ip -4 route sh default via 192.168.1.254 dev eth0.1 192.168.1.0/24 dev eth0.1 proto kernel scope link src 192.168.1.145 192.168.1.0/24 dev eth0.2 proto kernel scope link src 192.168.1.146 192.168.1.0/24 dev eth0.3 proto kernel scope link src 192.168.1.147 root@ubuntu:~# arping -c 5 -I eth0.1 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.145 eth0.1 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 6.936ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.986ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 0.654ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 5.137ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.426ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# arping -c 5 -I eth0.2 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.146 eth0.2 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 5.665ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 3.753ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 16.500ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 3.287ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 32.438ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# arping -c 5 -I eth0.3 192.168.1.254 ARPING 192.168.1.254 from 192.168.1.147 eth0.3 Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 4.422ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.429ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.321ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 40.423ms Unicast reply from 192.168.1.254 [58:98:35:57:a0:70] 2.268ms Sent 5 probes (1 broadcast(s)) Received 5 response(s) root@ubuntu:~# tcpdump -n -i eth0.1 -v & [1] 5317 root@ubuntu:~# ping -c5 -q -I eth0.1 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.145 eth0.1: 56(84) bytes of data. tcpdump: listening on eth0.1, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:37.612558 IP (tos 0x0, ttl 64, id 2595, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 2, length 64 13:18:37.618864 IP (tos 0x68, ttl 64, id 14493, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 2, length 64 13:18:37.743650 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:38.134997 IP (tos 0x0, ttl 128, id 23547, offset 0, flags [none], proto UDP (17), length 229) 192.168.1.86.138 > 192.168.1.255.138: NBT UDP PACKET(138) 13:18:38.614580 IP (tos 0x0, ttl 64, id 2596, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 3, length 64 13:18:38.793479 IP (tos 0x68, ttl 64, id 14495, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 3, length 64 13:18:39.151282 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:39.615612 IP (tos 0x0, ttl 64, id 2597, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.145 > 192.168.1.254: ICMP echo request, id 5318, seq 4, length 64 13:18:39.746981 IP (tos 0x68, ttl 64, id 14496, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.145: ICMP echo reply, id 5318, seq 4, length 64 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 5 received, 0% packet loss, time 4008ms rtt min/avg/max/mdev = 2.793/67.810/178.934/73.108 ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 9 packets captured 12 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.1 -v root@ubuntu:~# tcpdump -n -i eth0.2 -v & [1] 5320 root@ubuntu:~# ping -c5 -q -I eth0.2 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.146 eth0.2: 56(84) bytes of data. tcpdump: listening on eth0.2, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:41.536874 ARP, Ethernet (len 6), IPv4 (len 4), Reply 192.168.1.254 is-at 58:98:35:57:a0:70, length 46 13:18:41.536933 IP (tos 0x0, ttl 64, id 2599, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 1, length 64 13:18:41.539255 IP (tos 0x68, ttl 64, id 14507, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 1, length 64 13:18:42.127715 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:42.511725 IP (tos 0x0, ttl 64, id 2600, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 2, length 64 13:18:42.514385 IP (tos 0x68, ttl 64, id 14527, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 2, length 64 13:18:42.743856 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:43.511727 IP (tos 0x0, ttl 64, id 2601, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 3, length 64 13:18:43.513768 IP (tos 0x68, ttl 64, id 14528, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 3, length 64 13:18:43.637598 IP (tos 0x0, ttl 128, id 23551, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 255.255.255.255.17500: UDP, length 197 13:18:43.641185 IP (tos 0x0, ttl 128, id 23552, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 192.168.1.255.17500: UDP, length 197 13:18:43.641201 IP (tos 0x0, ttl 128, id 23553, offset 0, flags [none], proto UDP (17), length 225) 192.168.1.86.17500 > 255.255.255.255.17500: UDP, length 197 13:18:43.743890 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 13:18:44.510758 IP (tos 0x0, ttl 64, id 2602, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 4, length 64 13:18:44.512892 IP (tos 0x68, ttl 64, id 14538, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 4, length 64 13:18:45.510794 IP (tos 0x0, ttl 64, id 2603, offset 0, flags [DF], proto ICMP (1), length 84) 192.168.1.146 > 192.168.1.254: ICMP echo request, id 5321, seq 5, length 64 13:18:45.519701 IP (tos 0x68, ttl 64, id 14539, offset 0, flags [none], proto ICMP (1), length 84) 192.168.1.254 > 192.168.1.146: ICMP echo reply, id 5321, seq 5, length 64 13:18:49.287554 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:50.013463 IP (tos 0x0, ttl 255, id 50737, offset 0, flags [DF], proto UDP (17), length 73) 192.168.1.146.5353 > 224.0.0.251.5353: 0 [2q] PTR (QM)? _ipps._tcp.local. PTR (QM)? _ipp._tcp.local. (45) 13:18:50.218874 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:51.129961 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:52.197074 IP6 (hlim 255, next-header UDP (17) payload length: 53) 2001:818:d812:da00:200:ff:fe00:22.5353 > ff02::fb.5353: [udp sum ok] 0 [2q] PTR (QM)? _ipps._tcp.local. PTR (QM)? _ipp._tcp.local. (45) 13:18:54.128240 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 0 received, 100% packet loss, time 4000ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 13:18:54.657731 IP6 (class 0x68, hlim 255, next-header ICMPv6 (58) payload length: 32) fe80::5a98:35ff:fe57:e070 > ff02::1:ff6b:e9b4: [icmp6 sum ok] ICMP6, neighbor solicitation, length 32, who has 2001:818:d812:da00:8ae3:abff:fe6b:e9b4 source link-address option (1), length 8 (1): 58:98:35:57:a0:70 13:18:54.743174 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 192.168.1.87 tell 192.168.1.86, length 46 25 packets captured 26 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.2 -v root@ubuntu:~# tcpdump -n -i eth0.3 icmp & [1] 5324 root@ubuntu:~# ping -c5 -q -I eth0.3 192.168.1.254 PING 192.168.1.254 (192.168.1.254) from 192.168.1.147 eth0.3: 56(84) bytes of data. tcpdump: verbose output suppressed, use -v or -vv for full protocol decode listening on eth0.3, link-type EN10MB (Ethernet), capture size 65535 bytes 13:18:56.373434 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 1, length 64 13:18:57.372116 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 2, length 64 13:18:57.381263 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 2, length 64 13:18:58.371141 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 3, length 64 13:18:58.373275 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 3, length 64 13:18:59.371165 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 4, length 64 13:18:59.373259 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 4, length 64 13:19:00.371211 IP 192.168.1.147 > 192.168.1.254: ICMP echo request, id 5325, seq 5, length 64 13:19:00.373278 IP 192.168.1.254 > 192.168.1.147: ICMP echo reply, id 5325, seq 5, length 64 --- 192.168.1.254 ping statistics --- 5 packets transmitted, 1 received, 80% packet loss, time 4001ms rtt min/avg/max/mdev = 13.666/13.666/13.666/0.000 ms root@ubuntu:~# killall tcpdump >> /dev/null 2>&1 9 packets captured 10 packets received by filter 0 packets dropped by kernel [1]+ Done tcpdump -n -i eth0.3 icmp root@ubuntu:~# arp -n Address HWtype HWaddress Flags Mask Iface 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.1 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.2 192.168.1.254 ether 58:98:35:57:a0:70 C eth0.3

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  • The Alexandria Project, Chap. 11: Have I got an App for You!

    <b>Standards Blog:</b> "While CIA Agent Carl Cummings was being taught to heel, Frank was sitting at his kitchen table, tapping away at the cramped keyboard of a cheap netbook connected to a neighbor&#8217;s unsecured WiFi network. Even this was risky, he reminded himself, so this brief session would have to be his last until he moved on."

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