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  • How to get cursor to follow text when reading a web page?

    - by Jack BeNimble
    I know this isn't strictly program related, but I think I've seen this answer on SO before and lost track of it. The specific question has to do with reading an electronic document. I find it helpful to move the cursor across the words as I'm reading them. This works great with Word documents, but I'm unable to do it with web pages. Is there a way to make a web page see and respond to cursor movement?

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  • How to set cursor at the end in a TEXTAREA? (by not using jQuery)

    - by Brian Hawk
    Is there a way to set the cursor at the end in a TEXTAREA tag? I'm using Firefox 3.6 and I don't need it to work in IE or Chrome. JavaScript is ok but it seems all the related answers in here use onfocus() event, which seems to be useless because when user clicks on anywhere within textarea, Firefox sets cursor position to there. I have a long text to display in a textarea so that it displays the last portion (making it easier to add something at the end).

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  • Query.fetch(limit=2000) only moves cursor forward by 1000 entities?

    - by Liron
    Let's say I have 2500 MyModel entities in my datastore, and I run this code: query = MyModel.all() first_batch = query.fetch(2000) len(first_batch) # 2000 next_query = MyModel.all().with_cursor(query.cursor()) next_batch = next_query.fetch(2000) What do you think len(next_batch) is? 500, right? Nope - it's 1500. Apparently the query cursor never moves forward by more than 1000, even when the query itself returns more than 1000 entities. Should I do something different or is it just an App Engine bug?

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  • PTLQueue : a scalable bounded-capacity MPMC queue

    - by Dave
    Title: Fast concurrent MPMC queue -- I've used the following concurrent queue algorithm enough that it warrants a blog entry. I'll sketch out the design of a fast and scalable multiple-producer multiple-consumer (MPSC) concurrent queue called PTLQueue. The queue has bounded capacity and is implemented via a circular array. Bounded capacity can be a useful property if there's a mismatch between producer rates and consumer rates where an unbounded queue might otherwise result in excessive memory consumption by virtue of the container nodes that -- in some queue implementations -- are used to hold values. A bounded-capacity queue can provide flow control between components. Beware, however, that bounded collections can also result in resource deadlock if abused. The put() and take() operators are partial and wait for the collection to become non-full or non-empty, respectively. Put() and take() do not allocate memory, and are not vulnerable to the ABA pathologies. The PTLQueue algorithm can be implemented equally well in C/C++ and Java. Partial operators are often more convenient than total methods. In many use cases if the preconditions aren't met, there's nothing else useful the thread can do, so it may as well wait via a partial method. An exception is in the case of work-stealing queues where a thief might scan a set of queues from which it could potentially steal. Total methods return ASAP with a success-failure indication. (It's tempting to describe a queue or API as blocking or non-blocking instead of partial or total, but non-blocking is already an overloaded concurrency term. Perhaps waiting/non-waiting or patient/impatient might be better terms). It's also trivial to construct partial operators by busy-waiting via total operators, but such constructs may be less efficient than an operator explicitly and intentionally designed to wait. A PTLQueue instance contains an array of slots, where each slot has volatile Turn and MailBox fields. The array has power-of-two length allowing mod/div operations to be replaced by masking. We assume sensible padding and alignment to reduce the impact of false sharing. (On x86 I recommend 128-byte alignment and padding because of the adjacent-sector prefetch facility). Each queue also has PutCursor and TakeCursor cursor variables, each of which should be sequestered as the sole occupant of a cache line or sector. You can opt to use 64-bit integers if concerned about wrap-around aliasing in the cursor variables. Put(null) is considered illegal, but the caller or implementation can easily check for and convert null to a distinguished non-null proxy value if null happens to be a value you'd like to pass. Take() will accordingly convert the proxy value back to null. An advantage of PTLQueue is that you can use atomic fetch-and-increment for the partial methods. We initialize each slot at index I with (Turn=I, MailBox=null). Both cursors are initially 0. All shared variables are considered "volatile" and atomics such as CAS and AtomicFetchAndIncrement are presumed to have bidirectional fence semantics. Finally T is the templated type. I've sketched out a total tryTake() method below that allows the caller to poll the queue. tryPut() has an analogous construction. Zebra stripping : alternating row colors for nice-looking code listings. See also google code "prettify" : https://code.google.com/p/google-code-prettify/ Prettify is a javascript module that yields the HTML/CSS/JS equivalent of pretty-print. -- pre:nth-child(odd) { background-color:#ff0000; } pre:nth-child(even) { background-color:#0000ff; } border-left: 11px solid #ccc; margin: 1.7em 0 1.7em 0.3em; background-color:#BFB; font-size:12px; line-height:65%; " // PTLQueue : Put(v) : // producer : partial method - waits as necessary assert v != null assert Mask = 1 && (Mask & (Mask+1)) == 0 // Document invariants // doorway step // Obtain a sequence number -- ticket // As a practical concern the ticket value is temporally unique // The ticket also identifies and selects a slot auto tkt = AtomicFetchIncrement (&PutCursor, 1) slot * s = &Slots[tkt & Mask] // waiting phase : // wait for slot's generation to match the tkt value assigned to this put() invocation. // The "generation" is implicitly encoded as the upper bits in the cursor // above those used to specify the index : tkt div (Mask+1) // The generation serves as an epoch number to identify a cohort of threads // accessing disjoint slots while s-Turn != tkt : Pause assert s-MailBox == null s-MailBox = v // deposit and pass message Take() : // consumer : partial method - waits as necessary auto tkt = AtomicFetchIncrement (&TakeCursor,1) slot * s = &Slots[tkt & Mask] // 2-stage waiting : // First wait for turn for our generation // Acquire exclusive "take" access to slot's MailBox field // Then wait for the slot to become occupied while s-Turn != tkt : Pause // Concurrency in this section of code is now reduced to just 1 producer thread // vs 1 consumer thread. // For a given queue and slot, there will be most one Take() operation running // in this section. // Consumer waits for producer to arrive and make slot non-empty // Extract message; clear mailbox; advance Turn indicator // We have an obvious happens-before relation : // Put(m) happens-before corresponding Take() that returns that same "m" for T v = s-MailBox if v != null : s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 // unlock slot to admit next producer and consumer return v Pause tryTake() : // total method - returns ASAP with failure indication for auto tkt = TakeCursor slot * s = &Slots[tkt & Mask] if s-Turn != tkt : return null T v = s-MailBox // presumptive return value if v == null : return null // ratify tkt and v values and commit by advancing cursor if CAS (&TakeCursor, tkt, tkt+1) != tkt : continue s-MailBox = null ST-ST barrier s-Turn = tkt + Mask + 1 return v The basic idea derives from the Partitioned Ticket Lock "PTL" (US20120240126-A1) and the MultiLane Concurrent Bag (US8689237). The latter is essentially a circular ring-buffer where the elements themselves are queues or concurrent collections. You can think of the PTLQueue as a partitioned ticket lock "PTL" augmented to pass values from lock to unlock via the slots. Alternatively, you could conceptualize of PTLQueue as a degenerate MultiLane bag where each slot or "lane" consists of a simple single-word MailBox instead of a general queue. Each lane in PTLQueue also has a private Turn field which acts like the Turn (Grant) variables found in PTL. Turn enforces strict FIFO ordering and restricts concurrency on the slot mailbox field to at most one simultaneous put() and take() operation. PTL uses a single "ticket" variable and per-slot Turn (grant) fields while MultiLane has distinct PutCursor and TakeCursor cursors and abstract per-slot sub-queues. Both PTL and MultiLane advance their cursor and ticket variables with atomic fetch-and-increment. PTLQueue borrows from both PTL and MultiLane and has distinct put and take cursors and per-slot Turn fields. Instead of a per-slot queues, PTLQueue uses a simple single-word MailBox field. PutCursor and TakeCursor act like a pair of ticket locks, conferring "put" and "take" access to a given slot. PutCursor, for instance, assigns an incoming put() request to a slot and serves as a PTL "Ticket" to acquire "put" permission to that slot's MailBox field. To better explain the operation of PTLQueue we deconstruct the operation of put() and take() as follows. Put() first increments PutCursor obtaining a new unique ticket. That ticket value also identifies a slot. Put() next waits for that slot's Turn field to match that ticket value. This is tantamount to using a PTL to acquire "put" permission on the slot's MailBox field. Finally, having obtained exclusive "put" permission on the slot, put() stores the message value into the slot's MailBox. Take() similarly advances TakeCursor, identifying a slot, and then acquires and secures "take" permission on a slot by waiting for Turn. Take() then waits for the slot's MailBox to become non-empty, extracts the message, and clears MailBox. Finally, take() advances the slot's Turn field, which releases both "put" and "take" access to the slot's MailBox. Note the asymmetry : put() acquires "put" access to the slot, but take() releases that lock. At any given time, for a given slot in a PTLQueue, at most one thread has "put" access and at most one thread has "take" access. This restricts concurrency from general MPMC to 1-vs-1. We have 2 ticket locks -- one for put() and one for take() -- each with its own "ticket" variable in the form of the corresponding cursor, but they share a single "Grant" egress variable in the form of the slot's Turn variable. Advancing the PutCursor, for instance, serves two purposes. First, we obtain a unique ticket which identifies a slot. Second, incrementing the cursor is the doorway protocol step to acquire the per-slot mutual exclusion "put" lock. The cursors and operations to increment those cursors serve double-duty : slot-selection and ticket assignment for locking the slot's MailBox field. At any given time a slot MailBox field can be in one of the following states: empty with no pending operations -- neutral state; empty with one or more waiting take() operations pending -- deficit; occupied with no pending operations; occupied with one or more waiting put() operations -- surplus; empty with a pending put() or pending put() and take() operations -- transitional; or occupied with a pending take() or pending put() and take() operations -- transitional. The partial put() and take() operators can be implemented with an atomic fetch-and-increment operation, which may confer a performance advantage over a CAS-based loop. In addition we have independent PutCursor and TakeCursor cursors. Critically, a put() operation modifies PutCursor but does not access the TakeCursor and a take() operation modifies the TakeCursor cursor but does not access the PutCursor. This acts to reduce coherence traffic relative to some other queue designs. It's worth noting that slow threads or obstruction in one slot (or "lane") does not impede or obstruct operations in other slots -- this gives us some degree of obstruction isolation. PTLQueue is not lock-free, however. The implementation above is expressed with polite busy-waiting (Pause) but it's trivial to implement per-slot parking and unparking to deschedule waiting threads. It's also easy to convert the queue to a more general deque by replacing the PutCursor and TakeCursor cursors with Left/Front and Right/Back cursors that can move either direction. Specifically, to push and pop from the "left" side of the deque we would decrement and increment the Left cursor, respectively, and to push and pop from the "right" side of the deque we would increment and decrement the Right cursor, respectively. We used a variation of PTLQueue for message passing in our recent OPODIS 2013 paper. ul { list-style:none; padding-left:0; padding:0; margin:0; margin-left:0; } ul#myTagID { padding: 0px; margin: 0px; list-style:none; margin-left:0;} -- -- There's quite a bit of related literature in this area. I'll call out a few relevant references: Wilson's NYU Courant Institute UltraComputer dissertation from 1988 is classic and the canonical starting point : Operating System Data Structures for Shared-Memory MIMD Machines with Fetch-and-Add. Regarding provenance and priority, I think PTLQueue or queues effectively equivalent to PTLQueue have been independently rediscovered a number of times. See CB-Queue and BNPBV, below, for instance. But Wilson's dissertation anticipates the basic idea and seems to predate all the others. Gottlieb et al : Basic Techniques for the Efficient Coordination of Very Large Numbers of Cooperating Sequential Processors Orozco et al : CB-Queue in Toward high-throughput algorithms on many-core architectures which appeared in TACO 2012. Meneghin et al : BNPVB family in Performance evaluation of inter-thread communication mechanisms on multicore/multithreaded architecture Dmitry Vyukov : bounded MPMC queue (highly recommended) Alex Otenko : US8607249 (highly related). John Mellor-Crummey : Concurrent queues: Practical fetch-and-phi algorithms. Technical Report 229, Department of Computer Science, University of Rochester Thomasson : FIFO Distributed Bakery Algorithm (very similar to PTLQueue). Scott and Scherer : Dual Data Structures I'll propose an optimization left as an exercise for the reader. Say we wanted to reduce memory usage by eliminating inter-slot padding. Such padding is usually "dark" memory and otherwise unused and wasted. But eliminating the padding leaves us at risk of increased false sharing. Furthermore lets say it was usually the case that the PutCursor and TakeCursor were numerically close to each other. (That's true in some use cases). We might still reduce false sharing by incrementing the cursors by some value other than 1 that is not trivially small and is coprime with the number of slots. Alternatively, we might increment the cursor by one and mask as usual, resulting in a logical index. We then use that logical index value to index into a permutation table, yielding an effective index for use in the slot array. The permutation table would be constructed so that nearby logical indices would map to more distant effective indices. (Open question: what should that permutation look like? Possibly some perversion of a Gray code or De Bruijn sequence might be suitable). As an aside, say we need to busy-wait for some condition as follows : "while C == 0 : Pause". Lets say that C is usually non-zero, so we typically don't wait. But when C happens to be 0 we'll have to spin for some period, possibly brief. We can arrange for the code to be more machine-friendly with respect to the branch predictors by transforming the loop into : "if C == 0 : for { Pause; if C != 0 : break; }". Critically, we want to restructure the loop so there's one branch that controls entry and another that controls loop exit. A concern is that your compiler or JIT might be clever enough to transform this back to "while C == 0 : Pause". You can sometimes avoid this by inserting a call to a some type of very cheap "opaque" method that the compiler can't elide or reorder. On Solaris, for instance, you could use :"if C == 0 : { gethrtime(); for { Pause; if C != 0 : break; }}". It's worth noting the obvious duality between locks and queues. If you have strict FIFO lock implementation with local spinning and succession by direct handoff such as MCS or CLH,then you can usually transform that lock into a queue. Hidden commentary and annotations - invisible : * And of course there's a well-known duality between queues and locks, but I'll leave that topic for another blog post. * Compare and contrast : PTLQ vs PTL and MultiLane * Equivalent : Turn; seq; sequence; pos; position; ticket * Put = Lock; Deposit Take = identify and reserve slot; wait; extract & clear; unlock * conceptualize : Distinct PutLock and TakeLock implemented as ticket lock or PTL Distinct arrival cursors but share per-slot "Turn" variable provides exclusive role-based access to slot's mailbox field put() acquires exclusive access to a slot for purposes of "deposit" assigns slot round-robin and then acquires deposit access rights/perms to that slot take() acquires exclusive access to slot for purposes of "withdrawal" assigns slot round-robin and then acquires withdrawal access rights/perms to that slot At any given time, only one thread can have withdrawal access to a slot at any given time, only one thread can have deposit access to a slot Permissible for T1 to have deposit access and T2 to simultaneously have withdrawal access * round-robin for the purposes of; role-based; access mode; access role mailslot; mailbox; allocate/assign/identify slot rights; permission; license; access permission; * PTL/Ticket hybrid Asymmetric usage ; owner oblivious lock-unlock pairing K-exclusion add Grant cursor pass message m from lock to unlock via Slots[] array Cursor performs 2 functions : + PTL ticket + Assigns request to slot in round-robin fashion Deconstruct protocol : explication put() : allocate slot in round-robin fashion acquire PTL for "put" access store message into slot associated with PTL index take() : Acquire PTL for "take" access // doorway step seq = fetchAdd (&Grant, 1) s = &Slots[seq & Mask] // waiting phase while s-Turn != seq : pause Extract : wait for s-mailbox to be full v = s-mailbox s-mailbox = null Release PTL for both "put" and "take" access s-Turn = seq + Mask + 1 * Slot round-robin assignment and lock "doorway" protocol leverage the same cursor and FetchAdd operation on that cursor FetchAdd (&Cursor,1) + round-robin slot assignment and dispersal + PTL/ticket lock "doorway" step waiting phase is via "Turn" field in slot * PTLQueue uses 2 cursors -- put and take. Acquire "put" access to slot via PTL-like lock Acquire "take" access to slot via PTL-like lock 2 locks : put and take -- at most one thread can access slot's mailbox Both locks use same "turn" field Like multilane : 2 cursors : put and take slot is simple 1-capacity mailbox instead of queue Borrow per-slot turn/grant from PTL Provides strict FIFO Lock slot : put-vs-put take-vs-take at most one put accesses slot at any one time at most one put accesses take at any one time reduction to 1-vs-1 instead of N-vs-M concurrency Per slot locks for put/take Release put/take by advancing turn * is instrumental in ... * P-V Semaphore vs lock vs K-exclusion * See also : FastQueues-excerpt.java dice-etc/queue-mpmc-bounded-blocking-circular-xadd/ * PTLQueue is the same as PTLQB - identical * Expedient return; ASAP; prompt; immediately * Lamport's Bakery algorithm : doorway step then waiting phase Threads arriving at doorway obtain a unique ticket number Threads enter in ticket order * In the terminology of Reed and Kanodia a ticket lock corresponds to the busy-wait implementation of a semaphore using an eventcount and a sequencer It can also be thought of as an optimization of Lamport's bakery lock was designed for fault-tolerance rather than performance Instead of spinning on the release counter, processors using a bakery lock repeatedly examine the tickets of their peers --

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  • Pixel Shader Giving Black output

    - by Yashwinder
    I am coding in C# using Windows Forms and the SlimDX API to show the effect of a pixel shader. When I am setting the pixel shader, I am getting a black output screen but if I am not using the pixel shader then I am getting my image rendered on the screen. I have the following C# code using System; using System.Collections.Generic; using System.Linq; using System.Windows.Forms; using System.Runtime.InteropServices; using SlimDX.Direct3D9; using SlimDX; using SlimDX.Windows; using System.Drawing; using System.Threading; namespace WindowsFormsApplication1 { // Vertex structure. [StructLayout(LayoutKind.Sequential)] struct Vertex { public Vector3 Position; public float Tu; public float Tv; public static int SizeBytes { get { return Marshal.SizeOf(typeof(Vertex)); } } public static VertexFormat Format { get { return VertexFormat.Position | VertexFormat.Texture1; } } } static class Program { public static Device D3DDevice; // Direct3D device. public static VertexBuffer Vertices; // Vertex buffer object used to hold vertices. public static Texture Image; // Texture object to hold the image loaded from a file. public static int time; // Used for rotation caculations. public static float angle; // Angle of rottaion. public static Form1 Window =new Form1(); public static string filepath; static VertexShader vertexShader = null; static ConstantTable constantTable = null; static ImageInformation info; [STAThread] static void Main() { filepath = "C:\\Users\\Public\\Pictures\\Sample Pictures\\Garden.jpg"; info = new ImageInformation(); info = ImageInformation.FromFile(filepath); PresentParameters presentParams = new PresentParameters(); // Below are the required bare mininum, needed to initialize the D3D device. presentParams.BackBufferHeight = info.Height; // BackBufferHeight, set to the Window's height. presentParams.BackBufferWidth = info.Width+200; // BackBufferWidth, set to the Window's width. presentParams.Windowed =true; presentParams.DeviceWindowHandle = Window.panel2 .Handle; // DeviceWindowHandle, set to the Window's handle. // Create the device. D3DDevice = new Device(new Direct3D (), 0, DeviceType.Hardware, Window.Handle, CreateFlags.HardwareVertexProcessing, presentParams); // Create the vertex buffer and fill with the triangle vertices. (Non-indexed) // Remember 3 vetices for a triangle, 2 tris per quad = 6. Vertices = new VertexBuffer(D3DDevice, 6 * Vertex.SizeBytes, Usage.WriteOnly, VertexFormat.None, Pool.Managed); DataStream stream = Vertices.Lock(0, 0, LockFlags.None); stream.WriteRange(BuildVertexData()); Vertices.Unlock(); // Create the texture. Image = Texture.FromFile(D3DDevice,filepath ); // Turn off culling, so we see the front and back of the triangle D3DDevice.SetRenderState(RenderState.CullMode, Cull.None); // Turn off lighting D3DDevice.SetRenderState(RenderState.Lighting, false); ShaderBytecode sbcv = ShaderBytecode.CompileFromFile("C:\\Users\\yashwinder singh\\Desktop\\vertexShader.vs", "vs_main", "vs_1_1", ShaderFlags.None); constantTable = sbcv.ConstantTable; vertexShader = new VertexShader(D3DDevice, sbcv); ShaderBytecode sbc = ShaderBytecode.CompileFromFile("C:\\Users\\yashwinder singh\\Desktop\\pixelShader.txt", "ps_main", "ps_3_0", ShaderFlags.None); PixelShader ps = new PixelShader(D3DDevice, sbc); VertexDeclaration vertexDecl = new VertexDeclaration(D3DDevice, new[] { new VertexElement(0, 0, DeclarationType.Float3, DeclarationMethod.Default, DeclarationUsage.PositionTransformed, 0), new VertexElement(0, 12, DeclarationType.Float2 , DeclarationMethod.Default, DeclarationUsage.TextureCoordinate , 0), VertexElement.VertexDeclarationEnd }); Application.EnableVisualStyles(); MessagePump.Run(Window, () => { // Clear the backbuffer to a black color. D3DDevice.Clear(ClearFlags.Target | ClearFlags.ZBuffer, Color.Black, 1.0f, 0); // Begin the scene. D3DDevice.BeginScene(); // Setup the world, view and projection matrices. //D3DDevice.VertexShader = vertexShader; //D3DDevice.PixelShader = ps; // Render the vertex buffer. D3DDevice.SetStreamSource(0, Vertices, 0, Vertex.SizeBytes); D3DDevice.VertexFormat = Vertex.Format; // Setup our texture. Using Textures introduces the texture stage states, // which govern how Textures get blended together (in the case of multiple // Textures) and lighting information. D3DDevice.SetTexture(0, Image); // Now drawing 2 triangles, for a quad. D3DDevice.DrawPrimitives(PrimitiveType.TriangleList , 0, 2); // End the scene. D3DDevice.EndScene(); // Present the backbuffer contents to the screen. D3DDevice.Present(); }); if (Image != null) Image.Dispose(); if (Vertices != null) Vertices.Dispose(); if (D3DDevice != null) D3DDevice.Dispose(); } private static Vertex[] BuildVertexData() { Vertex[] vertexData = new Vertex[6]; vertexData[0].Position = new Vector3(-1.0f, 1.0f, 0.0f); vertexData[0].Tu = 0.0f; vertexData[0].Tv = 0.0f; vertexData[1].Position = new Vector3(-1.0f, -1.0f, 0.0f); vertexData[1].Tu = 0.0f; vertexData[1].Tv = 1.0f; vertexData[2].Position = new Vector3(1.0f, 1.0f, 0.0f); vertexData[2].Tu = 1.0f; vertexData[2].Tv = 0.0f; vertexData[3].Position = new Vector3(-1.0f, -1.0f, 0.0f); vertexData[3].Tu = 0.0f; vertexData[3].Tv = 1.0f; vertexData[4].Position = new Vector3(1.0f, -1.0f, 0.0f); vertexData[4].Tu = 1.0f; vertexData[4].Tv = 1.0f; vertexData[5].Position = new Vector3(1.0f, 1.0f, 0.0f); vertexData[5].Tu = 1.0f; vertexData[5].Tv = 0.0f; return vertexData; } } } And my pixel shader and vertex shader code are as following // Pixel shader input structure struct PS_INPUT { float4 Position : POSITION; float2 Texture : TEXCOORD0; }; // Pixel shader output structure struct PS_OUTPUT { float4 Color : COLOR0; }; // Global variables sampler2D Tex0; // Name: Simple Pixel Shader // Type: Pixel shader // Desc: Fetch texture and blend with constant color // PS_OUTPUT ps_main( in PS_INPUT In ) { PS_OUTPUT Out; //create an output pixel Out.Color = tex2D(Tex0, In.Texture); //do a texture lookup Out.Color *= float4(0.9f, 0.8f, 0.0f, 1); //do a simple effect return Out; //return output pixel } // Vertex shader input structure struct VS_INPUT { float4 Position : POSITION; float2 Texture : TEXCOORD0; }; // Vertex shader output structure struct VS_OUTPUT { float4 Position : POSITION; float2 Texture : TEXCOORD0; }; // Global variables float4x4 WorldViewProj; // Name: Simple Vertex Shader // Type: Vertex shader // Desc: Vertex transformation and texture coord pass-through // VS_OUTPUT vs_main( in VS_INPUT In ) { VS_OUTPUT Out; //create an output vertex Out.Position = mul(In.Position, WorldViewProj); //apply vertex transformation Out.Texture = In.Texture; //copy original texcoords return Out; //return output vertex }

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  • A* PathFinding Poor Performance

    - by RedShft
    After debugging for a few hours, the algorithm seems to be working. Right now to check if it works i'm checking the end node position to the currentNode position when the while loop quits. So far the values look correct. The problem is, the farther I get from the NPC, who is current stationary, the worse the performance gets. It gets to a point where the game is unplayable less than 10 fps. My current PathGraph is 2500 nodes, which I believe is pretty small, right? Any ideas on how to improve performance? struct Node { bool walkable; //Whether this node is blocked or open vect2 position; //The tile's position on the map in pixels int xIndex, yIndex; //The index values of the tile in the array Node*[4] connections; //An array of pointers to nodes this current node connects to Node* parent; int gScore; int hScore; int fScore; } class AStar { private: SList!Node openList; SList!Node closedList; //Node*[4] connections; //The connections of the current node; Node currentNode; //The current node being processed Node[] Path; //The path found; const int connectionCost = 10; Node start, end; ////////////////////////////////////////////////////////// void AddToList(ref SList!Node list, ref Node node ) { list.insert( node ); } void RemoveFrom(ref SList!Node list, ref Node node ) { foreach( elem; list ) { if( node.xIndex == elem.xIndex && node.yIndex == elem.yIndex ) { auto a = find( list[] , elem ); list.linearRemove( take(a, 1 ) ); } } } bool IsInList( SList!Node list, ref Node node ) { foreach( elem; list ) { if( node.xIndex == elem.xIndex && node.yIndex == elem.yIndex ) return true; } return false; } void ClearList( SList!Node list ) { list.clear; } void SetParentNode( ref Node parent, ref Node child ) { child.parent = &parent; } void SetStartAndEndNode( vect2 vStart, vect2 vEnd, Node[] PathGraph ) { int startXIndex, startYIndex; int endXIndex, endYIndex; startXIndex = cast(int)( vStart.x / 32 ); startYIndex = cast(int)( vStart.y / 32 ); endXIndex = cast(int)( vEnd.x / 32 ); endYIndex = cast(int)( vEnd.y / 32 ); foreach( node; PathGraph ) { if( node.xIndex == startXIndex && node.yIndex == startYIndex ) { start = node; } if( node.xIndex == endXIndex && node.yIndex == endYIndex ) { end = node; } } } void SetStartScores( ref Node start ) { start.gScore = 0; start.hScore = CalculateHScore( start, end ); start.fScore = CalculateFScore( start ); } Node GetLowestFScore() { Node lowest; lowest.fScore = 10000; foreach( elem; openList ) { if( elem.fScore < lowest.fScore ) lowest = elem; } return lowest; } //This function current sets the program into an infinite loop //I still need to debug to figure out why the parent nodes aren't correct void GeneratePath() { while( currentNode.position != start.position ) { Path ~= currentNode; currentNode = *currentNode.parent; } } void ReversePath() { Node[] temp; for(int i = Path.length - 1; i >= 0; i-- ) { temp ~= Path[i]; } Path = temp.dup; } public: //@FIXME It seems to find the path, but now performance is terrible void FindPath( vect2 vStart, vect2 vEnd, Node[] PathGraph ) { openList.clear; closedList.clear; SetStartAndEndNode( vStart, vEnd, PathGraph ); SetStartScores( start ); AddToList( openList, start ); while( currentNode.position != end.position ) { currentNode = GetLowestFScore(); if( currentNode.position == end.position ) break; else { RemoveFrom( openList, currentNode ); AddToList( closedList, currentNode ); for( int i = 0; i < currentNode.connections.length; i++ ) { if( currentNode.connections[i] is null ) continue; else { if( IsInList( closedList, *currentNode.connections[i] ) && currentNode.gScore < currentNode.connections[i].gScore ) { currentNode.connections[i].gScore = currentNode.gScore + connectionCost; currentNode.connections[i].hScore = abs( currentNode.connections[i].xIndex - end.xIndex ) + abs( currentNode.connections[i].yIndex - end.yIndex ); currentNode.connections[i].fScore = currentNode.connections[i].gScore + currentNode.connections[i].hScore; currentNode.connections[i].parent = &currentNode; } else if( IsInList( openList, *currentNode.connections[i] ) && currentNode.gScore < currentNode.connections[i].gScore ) { currentNode.connections[i].gScore = currentNode.gScore + connectionCost; currentNode.connections[i].hScore = abs( currentNode.connections[i].xIndex - end.xIndex ) + abs( currentNode.connections[i].yIndex - end.yIndex ); currentNode.connections[i].fScore = currentNode.connections[i].gScore + currentNode.connections[i].hScore; currentNode.connections[i].parent = &currentNode; } else { currentNode.connections[i].gScore = currentNode.gScore + connectionCost; currentNode.connections[i].hScore = abs( currentNode.connections[i].xIndex - end.xIndex ) + abs( currentNode.connections[i].yIndex - end.yIndex ); currentNode.connections[i].fScore = currentNode.connections[i].gScore + currentNode.connections[i].hScore; currentNode.connections[i].parent = &currentNode; AddToList( openList, *currentNode.connections[i] ); } } } } } writeln( "Current Node Position: ", currentNode.position ); writeln( "End Node Position: ", end.position ); if( currentNode.position == end.position ) { writeln( "Current Node Parent: ", currentNode.parent ); //GeneratePath(); //ReversePath(); } } Node[] GetPath() { return Path; } } This is my first attempt at A* so any help would be greatly appreciated.

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  • To display an album art from media store in android

    - by user1834724
    I'm not able to display album art from media store while listing albums,I'm getting following error Bad request for field slot 0,-1. numRows = 32, numColumns = 7 01-02 02:48:16.789: D/AndroidRuntime(4963): Shutting down VM 01-02 02:48:16.789: W/dalvikvm(4963): threadid=1: thread exiting with uncaught exception (group=0x4001e578) 01-02 02:48:16.804: E/AndroidRuntime(4963): FATAL EXCEPTION: main 01-02 02:48:16.804: E/AndroidRuntime(4963): java.lang.IllegalStateException: get field slot from row 0 col -1 failed Can anyone kindly help with this issue,Thanks in advance public class AlbumbsListActivity extends Activity { private ListAdapter albumListAdapter; private HashMap<Integer, Integer> albumInfo; private HashMap<Integer, Integer> albumListInfo; private HashMap<Integer, String> albumListTitleInfo; private String audioMediaId; private static final String TAG = "AlbumsListActivity"; Boolean showAlbumList = false; Boolean AlbumListTitle = false; ImageView album_art ; public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.albums_list_layout); Cursor cursor; ContentResolver cr = getApplicationContext().getContentResolver(); if (getIntent().hasExtra(Util.ALBUM_ID)) { int albumId = getIntent().getIntExtra(Util.ALBUM_ID, Util.MINUS_ONE); String[] projection = new String[] { Albums._ID, Albums.ALBUM, Albums.ARTIST, Albums.ALBUM_ART, Albums.NUMBER_OF_SONGS }; String selection = null; String[] selectionArgs = null; String sortOrder = Media.ALBUM + " ASC"; cursor = cr.query(Albums.EXTERNAL_CONTENT_URI, projection, selection, selectionArgs, sortOrder); /* final String[] ccols = new String[] { //MediaStore.Audio.Albums., MediaStore.Audio.Albums._ID, MediaStore.Audio.Albums.ALBUM, MediaStore.Audio.Albums.ARTIST, MediaStore.Audio.Albums.ALBUM_ART, MediaStore.Audio.Albums.NUMBER_OF_SONGS }; cursor = cr.query(MediaStore.Audio.Albums.getContentUri( "external"), ccols, null, null, MediaStore.Audio.Albums.DEFAULT_SORT_ORDER);*/ showAlbumList = true; } else { String order = MediaStore.Audio.Albums.ALBUM + " ASC"; String where = MediaStore.Audio.Albums.ALBUM; cursor = managedQuery(Media.EXTERNAL_CONTENT_URI, DbUtil.projection, null, null, order); showAlbumList = false; } albumInfo = new HashMap<Integer, Integer>(); albumListInfo = new HashMap<Integer, Integer>(); ListView listView = (ListView) findViewById(R.id.mylist_album); listView.setFastScrollEnabled(true); listView.setOnItemLongClickListener(new ItemLongClickListener()); listView.setAdapter(new AlbumCursorAdapter(this, cursor, DbUtil.displayFields, DbUtil.displayViews,showAlbumList)); final Uri uri = MediaStore.Audio.Albums.EXTERNAL_CONTENT_URI; final Cursor albumListCursor = cr.query(uri, DbUtil.Albumprojection, null, null, null); } private class AlbumCursorAdapter extends SimpleCursorAdapter implements SectionIndexer{ private final Context context; private final Cursor cursorValues; private Time musicTime; private Boolean isAlbumList; private MusicAlphabetIndexer mIndexer; private int mTitleIdx; public AlbumCursorAdapter(Context context, Cursor cursor, String[] from, int[] to,Boolean isAlbumList) { super(context, 0, cursor, from, to); this.context = context; this.cursorValues = cursor; //musicTime = new Time(); this.isAlbumList = isAlbumList; } String albumName=""; String artistName = ""; String numberofsongs = ""; long albumid; @Override public View getView(int position, View convertView, ViewGroup parent) { View rowView = convertView; if (rowView == null) { LayoutInflater inflater = (LayoutInflater) context .getSystemService(Context.LAYOUT_INFLATER_SERVICE); rowView = inflater .inflate(R.layout.row_album_layout, parent, false); } this.cursorValues.moveToPosition(position); String title = ""; String artistName = ""; String albumName = ""; int count; long albumid = 0; String songDuration = ""; if (isAlbumList) { albumInfo.put( position, Integer.parseInt(this.cursorValues.getString(this.cursorValues .getColumnIndex(MediaStore.Audio.Albums._ID)))); artistName = this.cursorValues .getString(this.cursorValues .getColumnIndex(MediaStore.Audio.Albums.ARTIST)); albumName = this.cursorValues .getString(this.cursorValues .getColumnIndex(MediaStore.Audio.Albums.ALBUM)); albumid=Integer.parseInt(this.cursorValues.getString(this.cursorValues .getColumnIndex(MediaStore.Audio.Albums.ALBUM_ID))); } else { albumInfo.put(position, Integer.parseInt(this.cursorValues .getString(this.cursorValues .getColumnIndex(MediaStore.Audio.Media._ID)))); artistName = this.cursorValues.getString(this.cursorValues .getColumnIndex(MediaStore.Audio.Media.ARTIST)); albumName = this.cursorValues.getString(this.cursorValues .getColumnIndex(MediaStore.Audio.Media.ALBUM)); albumid=Integer.parseInt(this.cursorValues.getString(this.cursorValues .getColumnIndex(MediaStore.Audio.Media.ALBUM_ID))); } //code for Alphabetical Indexer mTitleIdx = cursorValues.getColumnIndex(MediaStore.Audio.Media.ALBUM); mIndexer = new MusicAlphabetIndexer(cursorValues, mTitleIdx, getResources().getString(R.string.fast_scroll_alphabet)); //end TextView metaone = (TextView) rowView.findViewById(R.id.album_name); TextView metatwo = (TextView) rowView.findViewById(R.id.artist_name); ImageView metafour = (ImageView) rowView.findViewById(R.id.album_art); TextView metathree = (TextView) rowView .findViewById(R.id.songs_count); metaone.setText(albumName); metatwo.setText(artistName); (metafour)getAlbumArt(albumid); System.out.println("albumid----------"+albumid); metaThree.setText(DbUtil.makeTimeString(context, secs)); getAlbumArt(albumid); } TextView metaone = (TextView) rowView.findViewById(R.id.album_name); TextView metatwo = (TextView) rowView.findViewById(R.id.artist_name); album_art = (ImageView) rowView.findViewById(R.id.album_art); //TextView metathree = (TextView) rowView.findViewById(R.id.songs_count); metaone.setText(albumName); metatwo.setText(artistName); return rowView; } } String albumArtUri = ""; private void getAlbumArt(long albumid) { Uri uri=ContentUris.withAppendedId(MediaStore.Audio.Albums.EXTERNAL_CONTENT_URI, albumid); System.out.println("hhhhhhhhhhh" + uri); Cursor cursor = getContentResolver().query( ContentUris.withAppendedId( MediaStore.Audio.Albums.EXTERNAL_CONTENT_URI, albumid), new String[] { MediaStore.Audio.AlbumColumns.ALBUM_ART }, null, null, null); if (cursor.moveToFirst()) { albumArtUri = cursor.getString(0); } System.out.println("kkkkkkkkkkkkkkkkkkk :" + albumArtUri); cursor.close(); if(albumArtUri != null){ Options opts = new Options(); opts.inJustDecodeBounds = true; Bitmap albumCoverBitmap = BitmapFactory.decodeFile(albumArtUri, opts); opts.inJustDecodeBounds = false; albumCoverBitmap = BitmapFactory.decodeFile(albumArtUri, opts); if(albumCoverBitmap != null) album_art.setImageBitmap(albumCoverBitmap); }else { // TODO: Options opts = new Options(); Bitmap albumCoverBitmap = BitmapFactory.decodeResource(getApplicationContext().getResources(), R.drawable.albumart_mp_unknown_list, opts); if(albumCoverBitmap != null) album_art.setImageBitmap(albumCoverBitmap); } } } }

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  • What do I need to know before accepting a contract position in the United States?

    - by Andrew
    I just received an initial job offer for a contract position as a PHP developer. I have never had a contract position before, so I don't know what the implications of this are, and how it differs from a salaried position with benefits. =/ What are some things that I should be aware of before accepting the contract position? (i.e. taxes, wages, benefits, etc) It also mentions that I will sign a "day-to-day contract". What does that mean? Resources Here are some links that I've collected so far: First timer's guide to contracting - Covers contracting in the U.K., but not the U.S. The contract employee's handbook - Talks about the differences between a "Contract Employee" and an "Independent Contractor"

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  • C# Multithreading Interview questions for a senior developer/designer position.

    - by Mohit Bhandari
    I know there have been a great deal of interview questions posted on SO and specifically i like the post "Good C# interview questions for a Senior developer position" But i really wondered what sort of interview questions were asked to a senior developer or technical consultant on multithreading. Kindly provide me some of the interview questions which were asked in the interview on multithreading if possible kindly put the scenario based questions with some theoretical questions. As I came to know after disscusion with some of the people that some time interviewer might give you a scenario and ask you to implement it? @ Kindly add the specific questions which you have ever faced or asked to the other person in the interview other than only mentioning the concepts because people go through the concepts and still find it difficult to handle the interview questions.so any effort to add the specific question could actually help person to get a head start for the d-day

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  • What jquery code or plugin would I use to update the position of an element?

    - by Breadtruck
    I am using a jquery plugin from [ FilamentGroup ] called DateRangePicker. I have a simple form with two text inputs for the start and end date that I bind the DateRangePicker to using this $('input.tbDate').daterangepicker({ dateFormat: 'mm/dd/yy', earliestDate: new Date(minDate), latestDate: new Date(maxDate), datepickerOptions: { changeMonth: true, changeYear: true, minDate: new Date(minDate), maxDate: new Date(maxDate) } }); I have a collapsible table above this form that when shown, moves the form and the elements that the daterangepicker plugin is bound to, down lower on the page, but the daterangepicker appears to keep the position from when it was actually created. What code could I put in the daterangepicker's onShow Callback to update its position to be next to the element is was initially bound to? Or is there some specific jquery method or plugin that I could chain to the daterangepicker plugin so that it will update its position correctly. This would come in handy for some other plugins that I use that don't seem to keep their position relative to other elements correctly either.

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  • How to position a sprite in a 2D animation skeleton?

    - by Paul Manta
    Given two joints that define a bone, I would like to know how to decide where, between those two joints, I should draw the sprite. This should be a fairly simple thing to solve, but there is one thing that I am not sure about. After I've determined the rotation of the sprite (which is the absolute angle the joints form with the x-axis), I also need to determine the origin point from where I need to start drawing the transformed image. So how should I position the sprite between the two joints? Should I make the center of the image be the midpoint between the two joints, or should I make one the of the joints be the origin? Do these things matter that much (could the wrong positioning make the sprite move oddly during the animation)?

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  • How to switch position of two items in a Python list?

    - by mikl
    I haven’t been able to find a good solution for this problem on the net (probably because switch, position, list and Python are all such overloaded words). It’s rather simple – I have this list: ['title', 'email', 'password2', 'password1', 'first_name', 'last_name', 'next', 'newsletter'] I’d like to switch position of 'password2' and 'password1' – not knowing their exact position, only that they’re right next to one another and password2 is first. I’ve accomplished this with some rather long-winded list-subscripting, but I wondered if someone could come up with something a bit more elegant?

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  • Platformer Starter Kit - Collision Issues

    - by Cyral
    I'm having trouble with my game that is based off the XNA Platformer starter kit. My game uses smaller tiles (16x16) then the original (32x40) which I'm thinking may be having an effect on collision (Being it needs to be more precise). Standing on the edge of a tile and jumping causes the player to move off the the tile when he lands. And 80% of the time, when the player lands, he goes flying though SOLID tiles in a diagonal fashion. This is very annoying as it is almost impossible to test other features, when spawning and jumping will result in the player landing in another part of the level or falling off the edge completely. The code is as follows: /// <summary> /// Updates the player's velocity and position based on input, gravity, etc. /// </summary> public void ApplyPhysics(GameTime gameTime) { float elapsed = (float)gameTime.ElapsedGameTime.TotalSeconds; Vector2 previousPosition = Position; // Base velocity is a combination of horizontal movement control and // acceleration downward due to gravity. velocity.X += movement * MoveAcceleration * elapsed; velocity.Y = MathHelper.Clamp(velocity.Y + GravityAcceleration * elapsed, -MaxFallSpeed, MaxFallSpeed); velocity.Y = DoJump(velocity.Y, gameTime); // Apply pseudo-drag horizontally. if (IsOnGround) velocity.X *= GroundDragFactor; else velocity.X *= AirDragFactor; // Prevent the player from running faster than his top speed. velocity.X = MathHelper.Clamp(velocity.X, -MaxMoveSpeed, MaxMoveSpeed); // Apply velocity. Position += velocity * elapsed; Position = new Vector2((float)Math.Round(Position.X), (float)Math.Round(Position.Y)); // If the player is now colliding with the level, separate them. HandleCollisions(); // If the collision stopped us from moving, reset the velocity to zero. if (Position.X == previousPosition.X) velocity.X = 0; if (Position.Y == previousPosition.Y) velocity.Y = 0; } /// <summary> /// Detects and resolves all collisions between the player and his neighboring /// tiles. When a collision is detected, the player is pushed away along one /// axis to prevent overlapping. There is some special logic for the Y axis to /// handle platforms which behave differently depending on direction of movement. /// </summary> private void HandleCollisions() { // Get the player's bounding rectangle and find neighboring tiles. Rectangle bounds = BoundingRectangle; int leftTile = (int)Math.Floor((float)bounds.Left / Tile.Width); int rightTile = (int)Math.Ceiling(((float)bounds.Right / Tile.Width)) - 1; int topTile = (int)Math.Floor((float)bounds.Top / Tile.Height); int bottomTile = (int)Math.Ceiling(((float)bounds.Bottom / Tile.Height)) - 1; // Reset flag to search for ground collision. isOnGround = false; // For each potentially colliding tile, for (int y = topTile; y <= bottomTile; ++y) { for (int x = leftTile; x <= rightTile; ++x) { // If this tile is collidable, ItemCollision collision = Level.GetCollision(x, y); if (collision != ItemCollision.Passable) { // Determine collision depth (with direction) and magnitude. Rectangle tileBounds = Level.GetBounds(x, y); Vector2 depth = RectangleExtensions.GetIntersectionDepth(bounds, tileBounds); if (depth != Vector2.Zero) { float absDepthX = Math.Abs(depth.X); float absDepthY = Math.Abs(depth.Y); // Resolve the collision along the shallow axis. if (absDepthY < absDepthX || collision == ItemCollision.Platform) { // If we crossed the top of a tile, we are on the ground. if (previousBottom <= tileBounds.Top) isOnGround = true; // Ignore platforms, unless we are on the ground. if (collision == ItemCollision.Impassable || IsOnGround) { // Resolve the collision along the Y axis. Position = new Vector2(Position.X, Position.Y + depth.Y); // Perform further collisions with the new bounds. bounds = BoundingRectangle; } } else if (collision == ItemCollision.Impassable) // Ignore platforms. { // Resolve the collision along the X axis. Position = new Vector2(Position.X + depth.X, Position.Y); // Perform further collisions with the new bounds. bounds = BoundingRectangle; } } } } } // Save the new bounds bottom. previousBottom = bounds.Bottom; } It also tends to jitter a little bit sometimes, I'm solved some of this with some fixes I found here on stackexchange, But Ive only seen one other case of the flying though blocks problem. This question seems to have a similar problem in the video, but mine is more crazy. Again this is a very annoying bug! Any help would be greatly appreciated! EDIT: Speed stuff // Constants for controling horizontal movement private const float MoveAcceleration = 13000.0f; private const float MaxMoveSpeed = 1750.0f; private const float GroundDragFactor = 0.48f; private const float AirDragFactor = 0.58f; // Constants for controlling vertical movement private const float MaxJumpTime = 0.35f; private const float JumpLaunchVelocity = -3500.0f; private const float GravityAcceleration = 3400.0f; private const float MaxFallSpeed = 550.0f; private const float JumpControlPower = 0.14f;

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  • Moving in a diamond - enemy gets stuck

    - by Fibericon
    I have an enemy that I would like to move as follows: Start at (0, 200, 0) Move to (200, 0, 0) Move to (0, -200, 0) Move to (-200, 0, 0) Move to start point, repeat as long as it remains active. This is what I've done to achieve that: if (position.X < 200 && position.Y > 0) { Velocity = new Vector3(1, -1, 0) * speed; } else if (position.X >= 200 && position.Y <= 0 && position.Y > -200) { Velocity = new Vector3(-1, -1, 0) * speed; } else if (position.X <= 0 && position.Y <= -200) { Velocity = new Vector3(-1, 1, 0) * speed; } else { Velocity = new Vector3(1, 1, 0) * speed; } It moves to the second point, but then gets stuck and appears to vibrate in place. How should I be doing this?

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  • Black Screen: How to set Projection/View Matrix

    - by Lisa
    I have a Windows Phone 8 C#/XAML with DirectX component project. I'm rendering some particles, but each particle is a rectangle versus a square (as I've set the vertices to be positions equally offset from each other). I used an Identity matrix in the view and projection matrix. I decided to add the windows aspect ratio to prevent the rectangles. But now I get a black screen. None of the particles are rendered now. I don't know what's wrong with my matrices. Can anyone see the problem? These are the default matrices in Microsoft's project example. View Matrix: XMVECTOR eye = XMVectorSet(0.0f, 0.7f, 1.5f, 0.0f); XMVECTOR at = XMVectorSet(0.0f, -0.1f, 0.0f, 0.0f); XMVECTOR up = XMVectorSet(0.0f, 1.0f, 0.0f, 0.0f); XMStoreFloat4x4(&m_constantBufferData.view, XMMatrixTranspose(XMMatrixLookAtRH(eye, at, up))); Projection Matrix: void CubeRenderer::CreateWindowSizeDependentResources() { Direct3DBase::CreateWindowSizeDependentResources(); float aspectRatio = m_windowBounds.Width / m_windowBounds.Height; float fovAngleY = 70.0f * XM_PI / 180.0f; if (aspectRatio < 1.0f) { fovAngleY /= aspectRatio; } XMStoreFloat4x4(&m_constantBufferData.projection, XMMatrixTranspose(XMMatrixPerspectiveFovRH(fovAngleY, aspectRatio, 0.01f, 100.0f))); } I've tried modifying them to use cocos2dx's WP8 example. XMMATRIX identityMatrix = XMMatrixIdentity(); float fovy = 60.0f; float aspect = m_windowBounds.Width / m_windowBounds.Height; float zNear = 0.1f; float zFar = 100.0f; float xmin, xmax, ymin, ymax; ymax = zNear * tanf(fovy * XM_PI / 360); ymin = -ymax; xmin = ymin * aspect; xmax = ymax * aspect; XMMATRIX tmpMatrix = XMMatrixPerspectiveOffCenterRH(xmin, xmax, ymin, ymax, zNear, zFar); XMMATRIX projectionMatrix = XMMatrixMultiply(tmpMatrix, identityMatrix); // View Matrix float fEyeX = m_windowBounds.Width * 0.5f; float fEyeY = m_windowBounds.Height * 0.5f; float fEyeZ = m_windowBounds.Height / 1.1566f; float fLookAtX = m_windowBounds.Width * 0.5f; float fLookAtY = m_windowBounds.Height * 0.5f; float fLookAtZ = 0.0f; float fUpX = 0.0f; float fUpY = 1.0f; float fUpZ = 0.0f; XMMATRIX tmpMatrix2 = XMMatrixLookAtRH(XMVectorSet(fEyeX,fEyeY,fEyeZ,0.f), XMVectorSet(fLookAtX,fLookAtY,fLookAtZ,0.f), XMVectorSet(fUpX,fUpY,fUpZ,0.f)); XMMATRIX viewMatrix = XMMatrixMultiply(tmpMatrix2, identityMatrix); XMStoreFloat4x4(&m_constantBufferData.view, viewMatrix); Vertex Shader cbuffer ModelViewProjectionConstantBuffer : register(b0) { //matrix model; matrix view; matrix projection; }; struct VertexInputType { float4 position : POSITION; float2 tex : TEXCOORD0; float4 color : COLOR; }; struct PixelInputType { float4 position : SV_POSITION; float2 tex : TEXCOORD0; float4 color : COLOR; }; PixelInputType main(VertexInputType input) { PixelInputType output; // Change the position vector to be 4 units for proper matrix calculations. input.position.w = 1.0f; //===================================== // TODO: ADDED for testing input.position.z = 0.0f; //===================================== // Calculate the position of the vertex against the world, view, and projection matrices. //output.position = mul(input.position, model); output.position = mul(input.position, view); output.position = mul(output.position, projection); // Store the texture coordinates for the pixel shader. output.tex = input.tex; // Store the particle color for the pixel shader. output.color = input.color; return output; } Before I render the shader, I set the view/projection matrices into the constant buffer void ParticleRenderer::SetShaderParameters() { ViewProjectionConstantBuffer* dataPtr; D3D11_MAPPED_SUBRESOURCE mappedResource; DX::ThrowIfFailed(m_d3dContext->Map(m_constantBuffer.Get(), 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource)); dataPtr = (ViewProjectionConstantBuffer*)mappedResource.pData; dataPtr->view = m_constantBufferData.view; dataPtr->projection = m_constantBufferData.projection; m_d3dContext->Unmap(m_constantBuffer.Get(), 0); // Now set the constant buffer in the vertex shader with the updated values. m_d3dContext->VSSetConstantBuffers(0, 1, m_constantBuffer.GetAddressOf() ); // Set shader texture resource in the pixel shader. m_d3dContext->PSSetShaderResources(0, 1, &m_textureView); } Nothing, black screen... I tried so many different look at, eye, and up vectors. I tried transposing the matrices. I've set the particle center position to always be (0, 0, 0), I tried different positions too, just to make sure they're not being rendered offscreen.

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  • How can I get unfiltered position in filtered ListView?

    - by Julius
    I am using ListView with ArrayAdapter to filter items in list. I have implemented onListItemClick() method to get clicked item position and call second activity using that value. For example I have countries in my list: Australia Belgium Botswana Belize ... Belgium has position 1 here. However, if i type "Be" to filter items, I get one item as a result: Belgium Now if I click on this item, I get position 0 in onListItemClick(). But this behavior does not fit my needs. How can I get this item's unfiltered position (eg. 1 instead of 0)?

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  • Advice for transitioning into a Java developer position from doing other types of web development?

    - by Rick
    I've been doing web programming and currently work at a company working with mainly PHP and Javascript. For a little while now I've been becoming more and more frustrated with the shortcomings of this type of development and want to move to a company with a more defined development process that values doing things the "right way" such as using Unit tests, dependency injection / IoC, etc. I've been learning JEE / Java as much as I can on my own time but would really like to make a switch to doing this as my career and leave behind the PHP world altogether. I'm just wondering if anyone can give me advice on which things to put my main focus on right now to make myself marketable as an entry level Java developer. Basically, I feel that I'm not really learning anything new at my current job that will benefit me and its only making me more and more frustrated so I figure if there is any way to position myself for a transition I would rather do it sooner than later. Thanks for any advice.

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  • Listing technologies on a resume for a software position when your background is game programming?

    - by Ford
    So I'm thinking about applying for a entry level position in the software industry but my limited experience working and all my notable experience in college is with game technologies. Sure, the languages transfer over well but most of the technologies I have experience with are all related to graphics programming, engines of various types, and such, and do not transfer over at all. I feel like it would be inappropriate to just take my game programming resume and basically replace the word game with software for the reasons mentioned but on the other hand if I take them out I will only have languages and some technologies that I have some small passing experience with- which will obviously not reflect well on me. Should I leave them out or put them in, and if so how can I spin them to be appropriate?

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  • Drag camera/view in a 3D world

    - by Dono
    I'm trying to make a Draggable view in a 3D world. Currently, I've made it using mouse position on the screen, but, when I move the distance traveled by my mouse is not equal to the distance traveled in the 3D world. So, I've tried to do that : Compute a ray from mouse position to 3D world. Calculate intersection with the ground. Check intersection difference old position <- new position. Translate camera with the difference. I've got a problem with this method: The ray is computed with the current camera's position I move the camera I compute the new ray with new camera position. The difference between old ray and new ray is now invalid. So, graphically my camera don't stop to move to previous/new position everytime. How can I do a draggable camera with another solution ? Thanks!

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  • Make Sprite Jump Upon a Platform

    - by Geore Shg
    I have been struggling to make a game like Doodle Jump where the sprite jumps on a platform. So how do you make a sprite jump upon platforms in XNA? Th platforms are represented by a list of positions like Public platformList As List(Of Vector2) This is the collision detection under update() Dim mainSpriteRect As Rectangle = New Rectangle(CInt(mainSprite.Position.X), CInt(mainSprite.Position.Y), mainSprite.texture.Width, mainSprite.texture.Height) 'a node is simply a class with the texture and position' For Each _node As Node In _gameMap.nodeList Dim blockRect As Rectangle = New Rectangle(CInt(_node.Position.X), CInt(_node.Position.Y), _BlocksTexture.Width, _BlocksTexture.Height) If mainSpriteRect.Intersects(blockRect) Then 'what should I do here? For example velocity and position?' End If If (_node.Position.Y > 800) Then nodeList.Remove(_node) End If Next

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  • GLSL: How to get pixel x,y,z world position?

    - by Rookie
    I want to adjust the colors depending on which xyz position they are in the world. I tried this in my fragment shader: vec4 pos = vec4(gl_FragCoord); // get pixel position but it seems that the z-coord is always towards my camera... how do i make the coords independent from my camera position/angle? Edit: if it matters, heres my vertex shader: gl_Position = ftransform(); Edit2: changed title, so i want world coords, not screen coords!

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