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  • Box2d too much for Circle/Circle collision detection?

    - by Joey Green
    I'm using cocos2d to program a game and am using box2d for collision detection. Everything in my game is a circle and for some reason I'm having a problem with some times things are not being detected as a collision when they should be. I'm thinking of rolling up my own collision detection since I don't think it would be too hard. Questions are: Would this approach work for collision detection between circles? a. get radius of circle A and circle B. b. get distance of the center of circle A and circle B c. if the distance is greater than or equal to the sum of circle A radius and circle B radius then we have a hit Should box2d be used for such simple collision detection? There are no physics in this game.

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  • Best approach for unit enemy "awareness" in RTS?

    - by Phil
    I'm using Unity3d to develop an RTS/TD hybrid prototype game. What is the best approach to have "awareness" between units and their enemies? Is it sane to have every unit check the distance to every enemy and engage if within range? The approach I'm going for right now is to have a trigger sphere on every unit. If an enemy enters the trigger, the unit becomes aware of the enemy and starts distance checking. I'm imagining that this would save some unnecessary checks? What's the best practice here (if there's such a thing)? Thanks for reading.

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  • Alcatel-Lucent Boosts Broadband Over Copper To 300Mbps

    - by Ratman21
    alphadogg at Slashdot writes "Alcatel-Lucent has come up with a way to [0]move data at 300Mbps over copper lines. So far the results have only been reproduced in a lab environment — real products and services won't be available for at least a year. From the article: 'Researchers at the company's Bell Labs demonstrated the 300Mbps technology over a distance of 400 meters using VDSL2 (Very high bitrate Digital Subscriber Line), according to Stefaan Vanhastel, director of product marketing at Alcatel-Lucent Wireline Networks. The test showed that it can also do 100Mbps over a distance of 1,000 meters, he said. Currently, copper is the most common broadband medium. About 65 percent of subscribers have a broadband connection that's based on DSL, compared to 20 percent for cable and 12 percent for fiber, according to market research company Point Topic. Today, the average advertised DSL speeds for residential users vary between 9.2 Mbps and 1.9Mbps in various parts of the world, Point Topic said.'" Discuss this story at: http://tech.slashdot.org/comments.pl?sid=10/04/21/239243

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  • A Quick HLSL Question (How to modify some HLSL code)

    - by electroflame
    Thanks for wanting to help! I'm trying to create a circular, repeating ring (that moves outward) on a texture. I've achieved this, to a degree, with the following code: float distance = length(inTex - in_ShipCenter); float time = in_Time; ///* Simple distance/time combination */ float2 colorIndex = float2(distance - time, .3); float4 shipColor = tex2D(BaseTexture, inTex); float4 ringColor = tex2D(ringTexture, colorIndex); float4 finalColor; finalColor.rgb = (shipColor.rgb) + (ringColor.rgb); finalColor.a = shipColor.a; // Use the base texture's alpha (transparency). return finalColor; This works, and works how I want it to. The ring moves outward from the center of the texture at a steady rate, and is constrained to the edges of the base texture (i.e. it won't continue past an edge). However, there are a few issues with it that I would like some help on, though. They are: By combining the color additively (when I set finalColor.rgb), it makes the resulting ring color much lighter than I want (which, is pretty much the definition of additive blending, but I don't really want additive blending in this case). I would really like to be able to pass in the color that I want the ring to be. Currently, I have to pass in a texture that contains the color of the ring, but I think that doing it that way is kind of wasteful and overly-cumbersome. I know that I'm probably being an idiot over this, so I greatly appreciate the help. Some other (possibly relevant) information: I'm using XNA. I'm applying this by providing it to a SpriteBatch (as an Effect). The SpriteBatch is using BlendState.NonPremultiplied. Thanks in advance! EDIT: Thanks for the answers thus far, as they've helped me get a better grasp of the color issue. However, I'm still unsure of how to pass a color in and not use a texture. i.e. Can I create a tex2D by using a float4 instead of a texture? Or can I make a texture from a float4 and pass the texture in to the tex2D? DOUBLE EDIT: Here's some example pictures: With the effect off: With the effect on: With the effect on, but with the color weighting set to full: As you can see, the color weighting makes the base texture completely black (The background is black, so it looks transparent). You can also see the red it's supposed to be, and then the white-ish it really is when blended additively.

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  • Collision detection when pathfinding with pathnodes, UDK

    - by Dave Voyles
    I'm trying to create a class that allows my AIController to path find using pathnodes (NOT NavMeshes). It's doing a swell job of going from point to point in a set order (although I would like for it to be a random patrol at some point), but it gets caught up on collision from time to time. I.E. He'll walk the same set path, and when he runs into the blocks in the middle of the map he continues to rub against them until they finish, and continues on his merry way to the next path node. How can I prevent this from happening, or at least have him move from the wall if he does a trace and detects that it is there? It looks like I need to use MoveToward() instead of MoveTo(), as MoveToward allows the pawn to adjust its course during movement. I'm just not sure of how to use those paramters. Mougli has a decent tutorial on it[/URL], but I can't seem to get it to work correctly with my pathnode array. class PathfindingAIController extends UDKBot; var array Waypoints; var int _PathNode; //declare it at the start so you can use it throughout the script var int CloseEnough; simulated function PostBeginPlay() { local PathNode Current; super.PostBeginPlay(); //add the pathnodes to the array foreach WorldInfo.AllActors(class'Pathnode',Current) { Waypoints.AddItem( Current ); } } simulated function Tick(float DeltaTime) { local int Distance; local Rotator DesiredRotation; super.Tick(DeltaTime); if (Pawn != None) { // Smoothly rotate the pawn towards the focal point DesiredRotation = Rotator(GetFocalPoint() - Pawn.Location); Pawn.FaceRotation(RLerp(Pawn.Rotation, DesiredRotation, 3.125f * DeltaTime, true), DeltaTime); } Distance = VSize2D(Pawn.Location - Waypoints[_PathNode].Location); if (Distance <= CloseEnough) { _PathNode++; } if (_PathNode >= Waypoints.Length) { _PathNode = 0; } GoToState('Pathfinding'); } auto state Pathfinding { Begin: if (Waypoints[_PathNode] != None) // make sure there is a pathnode to move to { MoveTo(Waypoints[_PathNode].Location); //move to it `log("STATE: Pathfinding"); } } DefaultProperties { CloseEnough=400 bIsplayer = True }

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  • Finding an A* heuristic for a directed graph

    - by Janis Peisenieks
    In a previous question, I asked about finding a route (or path if you will) in a city. That is all dandy. The solution I chose was with the A* algorithm, which really seems to suit my needs. What I find puzzling is heuristic. How do I find one in an environment without constant distance between 2 nodes? Meaning, not every 2 nodes have the same distance between them. What I have is nodes (junctures), streets with weight (which may also be one-way), a start/finish node (since the start and end is always in the same place) and a goal node. In an ordinary case, I would just use the same way I got to goal to go back, but since one of the streets could have been a one-way, that may not be possible. The main question How do I find a heuristic in a directed graph?

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  • obj-c classes and sub classes (Cocos2d) conversion

    - by Lewis
    Hi I'm using this version of cocos2d: https://github.com/krzysztofzablocki/CCNode-SFGestureRecognizers Which supports the UIGestureRecognizer within a CCLayer in a cocos2d scene like so: @interface HelloWorldLayer : CCLayer <UIGestureRecognizerDelegate> { } Now I want to make this custom gesture work within the scene, attaching it to a sprite in cocos2d: #import <Foundation/Foundation.h> #import <UIKit/UIGestureRecognizerSubclass.h> @protocol OneFingerRotationGestureRecognizerDelegate <NSObject> @optional - (void) rotation: (CGFloat) angle; - (void) finalAngle: (CGFloat) angle; @end @interface OneFingerRotationGestureRecognizer : UIGestureRecognizer { CGPoint midPoint; CGFloat innerRadius; CGFloat outerRadius; CGFloat cumulatedAngle; id <OneFingerRotationGestureRecognizerDelegate> target; } - (id) initWithMidPoint: (CGPoint) midPoint innerRadius: (CGFloat) innerRadius outerRadius: (CGFloat) outerRadius target: (id) target; - (void)reset; - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event; - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event; - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event; - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event; @end #include <math.h> #import "OneFingerRotationGestureRecognizer.h" @implementation OneFingerRotationGestureRecognizer // private helper functions CGFloat distanceBetweenPoints(CGPoint point1, CGPoint point2); CGFloat angleBetweenLinesInDegrees(CGPoint beginLineA, CGPoint endLineA, CGPoint beginLineB, CGPoint endLineB); - (id) initWithMidPoint: (CGPoint) _midPoint innerRadius: (CGFloat) _innerRadius outerRadius: (CGFloat) _outerRadius target: (id <OneFingerRotationGestureRecognizerDelegate>) _target { if ((self = [super initWithTarget: _target action: nil])) { midPoint = _midPoint; innerRadius = _innerRadius; outerRadius = _outerRadius; target = _target; } return self; } /** Calculates the distance between point1 and point 2. */ CGFloat distanceBetweenPoints(CGPoint point1, CGPoint point2) { CGFloat dx = point1.x - point2.x; CGFloat dy = point1.y - point2.y; return sqrt(dx*dx + dy*dy); } CGFloat angleBetweenLinesInDegrees(CGPoint beginLineA, CGPoint endLineA, CGPoint beginLineB, CGPoint endLineB) { CGFloat a = endLineA.x - beginLineA.x; CGFloat b = endLineA.y - beginLineA.y; CGFloat c = endLineB.x - beginLineB.x; CGFloat d = endLineB.y - beginLineB.y; CGFloat atanA = atan2(a, b); CGFloat atanB = atan2(c, d); // convert radiants to degrees return (atanA - atanB) * 180 / M_PI; } #pragma mark - UIGestureRecognizer implementation - (void)reset { [super reset]; cumulatedAngle = 0; } - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event { [super touchesBegan:touches withEvent:event]; if ([touches count] != 1) { self.state = UIGestureRecognizerStateFailed; return; } } - (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { [super touchesMoved:touches withEvent:event]; if (self.state == UIGestureRecognizerStateFailed) return; CGPoint nowPoint = [[touches anyObject] locationInView: self.view]; CGPoint prevPoint = [[touches anyObject] previousLocationInView: self.view]; // make sure the new point is within the area CGFloat distance = distanceBetweenPoints(midPoint, nowPoint); if ( innerRadius <= distance && distance <= outerRadius) { // calculate rotation angle between two points CGFloat angle = angleBetweenLinesInDegrees(midPoint, prevPoint, midPoint, nowPoint); // fix value, if the 12 o'clock position is between prevPoint and nowPoint if (angle > 180) { angle -= 360; } else if (angle < -180) { angle += 360; } // sum up single steps cumulatedAngle += angle; // call delegate if ([target respondsToSelector: @selector(rotation:)]) { [target rotation:angle]; } } else { // finger moved outside the area self.state = UIGestureRecognizerStateFailed; } } - (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event { [super touchesEnded:touches withEvent:event]; if (self.state == UIGestureRecognizerStatePossible) { self.state = UIGestureRecognizerStateRecognized; if ([target respondsToSelector: @selector(finalAngle:)]) { [target finalAngle:cumulatedAngle]; } } else { self.state = UIGestureRecognizerStateFailed; } cumulatedAngle = 0; } - (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event { [super touchesCancelled:touches withEvent:event]; self.state = UIGestureRecognizerStateFailed; cumulatedAngle = 0; } @end Header file for view controller: #import "OneFingerRotationGestureRecognizer.h" @interface OneFingerRotationGestureViewController : UIViewController <OneFingerRotationGestureRecognizerDelegate> @property (nonatomic, strong) IBOutlet UIImageView *image; @property (nonatomic, strong) IBOutlet UITextField *textDisplay; @end then this is in the .m file: gestureRecognizer = [[OneFingerRotationGestureRecognizer alloc] initWithMidPoint: midPoint innerRadius: outRadius / 3 outerRadius: outRadius target: self]; [self.view addGestureRecognizer: gestureRecognizer]; Now my question is, is it possible to add this custom gesture into the cocos2d project found on that github, and if so, what do I need to change in the OneFingerRotationGestureRecognizerDelegate to get it to work within cocos2d. Because at the minute it is setup in a standard iOS project and not a cocos2d project and I do not know enough about UIViews and classing/ sub classing in obj-c to get this to work. Also it seems to inherit from a UIView where cocos2d uses CCLayer. Kind regards, Lewis. I also realise I may have not included enough code from the custom gesture project for readers to interpret it fully, so the full project can be found here: https://github.com/melle/OneFingerRotationGestureDemo

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  • Oracle CRM For Public Sector, Commercial Business, Education

    - by michael.seback
    Chongqing Transport Commission Improves Management of Transport Projects The Chongqing Transport Commission is responsible for public passenger, road, and waterway transport in urban and rural areas of Chongqing. The commission administers the region's road and water industry; oversees the construction of transport infrastructure; and manages civil aviation, railroads, roads, waterways, ports, and wharves. "After studying the IT initiatives of other provincial transport commissions, we decided to use Siebel Public Sector to build our integrated transport service system. The Siebel software offers powerful functions that allow us to integrate information and improve the management of our road, rail, and waterway infrastructure projects." - Chen Xiaoming, Vice Director, Information Center, Chongqing Transport Commission. Read more here. Siemens Information Services Increases Productivity by 20% Siemens Information Services Pvt, Ltd. provides back-office account processing services to Siemens' vendors. The company works with Siemens' healthcare, energy, and industry divisions in Europe, the United States, and parts of the Asia-Pacific region. It approves financial services such as processing payroll, accounts data, purchase orders, invoices, and payments, and also creates service catalogs for customers and internal teams. "Oracle CRM ON Demand provides us with a complete view of each customer's data from the moment they log a request to the time we close it. This has eliminated manual requests, and improved the service we offer to our clients across the Asia-Pacific region." -Sunil Zutshi, General Manager, IT, Siemens Information Services Pvt, Ltd. Read more here. China Distance Education Holdings Improves Call Center Productivity by 24% China Distance Education Holdings Limited is a leading provider of online education. The organization offers 174 courses through 16 Web sites, including accounting, healthcare, law, and engineering. In 2010, 215,000 students were enrolled. "Online education is a fast growing sector in China. To maintain our competitiveness, we implemented Oracle Contact Center Anywhere to make it easier and faster for our call center staff to respond to student enquiries. As a result, their productivity increased by 24%." - Qin Songjiang, Chief Technology Officer, China Distance Education Holdings Limited. Read more here.

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  • Automatically zoom out the camera to show all players

    - by user36159
    I am building a game in XNA that takes place in a rectangular arena. The game is multiplayer and each player may go where they like within the arena. The camera is a perspective camera that looks directly downwards. The camera should be automatically repositioned based on the game state. Currently, the xy position is a weighted sum of the xy positions of important entities. I would like the camera's z position to be calculated from the xy coordinates so that it zooms out to the point where all important entities are visible. My current approach is to: hw = the greatest x distance from the camera to an important entity hh = the greatest y distance from the camera to an important entity Calculate z = max(hw / tan(FoVx), hh / tan(FoVy)) My code seems to almost work as it should, but the resulting z values are always too low by a factor of about 4. Any ideas?

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  • Automatically zoom out the camera to show all players (XNA)

    - by user36159
    I am building a game in XNA that takes place in a rectangular arena. The game is multiplayer and each player may go where they like within the arena. The camera is a persepective camera that looks directly downwards. The camera should be automatically repositioned based on the game state. Currently, the xy position is a weighted sum of the xy positions of important entities. I would like the camera's z position to be calculated from the xy coordinates so that it zooms out to the point where all important entities are visible. My current approach is to: hw = the greatest x distance from the camera to an important entity hh = the greatest y distance from the camera to an important entity Calculate z = max(hw / tan(FoVx), hh / tan(FoVy)) My code seems to almost work as it should, but the resulting z values are always too low by a factor of about 4. Any ideas?

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  • Find Nearest Object

    - by ultifinitus
    I have a fairly sizable game engine created, and I'm adding some needed features, such as this, how do I find the nearest object from a list of points? In this case, I could simply use the Pythagorean theorem to find the distance, and check the results. I know I can't simply add x and y, because that's the distance to the object, if you only took right angle turns. However I'm wondering if there's something else I could do? I also have a collision system, where essentially I turn objects into smaller objects on a smaller grid, kind of like a minimap, and only if objects exist in the same gridspace do I check for collisions, I could do the same thing, only make the gridspace larger to check for closeness. (rather than checking every. single. object) however that would take additional setup in my base class and clutter up the already cluttered object. TL;DR Question: Is there something efficient and accurate that I can use to detect which object is closest, based on a list of points and sizes?

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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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  • Need the co-ordinates of innerPolygon

    - by user960567
    Let say I have this diagram, Given that i have all the co-ordinates of outer polygon and the distance between inner and outer polygon is d is also given. How to calculate the inner polygon co-ordinates? Edit: I was able to solved the issue by getting the mid-points of all lines. From these mid-points I can move d distance, So I can get three points. No I have 3 points and 3 slopes. From this, I can get three new equations. Simultaneously, solving the equation get the 3 points.

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  • atheros wireless ar9285 driver

    - by nikola
    I have been having problems with wireless on Ubuntu 10 and above, Mint 11 and above. The problem is in the driver for the wireless... I can see that there is no driver installed and yet it works but reduced a lot, for example: on windows 7 ultimate 100% on distance of 1 meter (currently running) Mint Cinnamon 15 on same distance 70% when it goes under the 40 % it simply disconnects and than takes a lot of time to connect again I am new to Linux and I don't know anything about programming, yet I love the interface and look of the OS but don't want to reject it for couple of problems. There is, however, a problem with brightness control on laptop, it shows the notification and slider but with no effect The question is: Can somebody explain to me where to download and how to install the ar9285 driver for atheros wireless card laptop acer emachines eme529? or can someone explain this to me only for the LINUX MINT 15 http://www.jrhenkelmann.net/index.php?option=com_content&task=view&id=34 because the synaptic's interface is different than of mint 15 I KNOW this is Ubuntu community but the problems persist in all Linux versions

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  • Predicted target location

    - by user3256944
    I'm having an issue with calculating the predicted linear angle a projectile needs to move in to intersect a moving enemy ship for my 2D game. I've tried following the document here, but what I've have come up with is simply awful. protected Vector2 GetPredictedPosition(float angleToEnemy, ShipCompartment origin, ShipCompartment target) { // Below obviously won't compile (document wants a Vector, not sure how to get that from a single float?) Vector2 velocity = target.Thrust - 25f; // Closing velocity (25 is example projectile velocity) Vector2 distance = target.Position - origin.Position; // Range to close double time = distance.Length() / velocity.Length(); // Time // Garbage code, doesn't compile, this method is incorrect return target.Position + (target.Thrust * time); } I would be grateful if the community can help point out how this is done correctly.

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  • XNA VertexBuffer.SetData performance suggestions

    - by CodeSpeaker
    I have a 3d world in a grid layout where each grid cell contains its separate vertex and index buffer for the mesh/terrain of that cell. When the player moves outside the boundaries of his cell, i dynamically load more cells in his walking direction based on his viewing distance. This triggers x number of vertex and indexbuffer initializations depending on how many cells that needs to be generated and causes the framerate to drop annoyingly during this time. The generation of terrain data is handled in a separate thread and runs smoothly. The vertex and index buffers are added during the update cycle of the game loop. I´ve tried batching the number of cells to be processed to avoid sending too much data at once into the buffers, which worked ok at a shorter viewing distance (about 9 cells to process), but not as well at greater distances with around 30 cells to process. Any idea how i can optimize this?

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  • How to calculate shot angle and velocity to hit a moving target?

    - by Guen
    I am developing a 2D Android game and I am making an aiming algorithm for AI projectiles to hit enemies either following a path, or free moving. At the moment it just calculates where the target will be after a distance and fires a projectile to meet it at that distance. Of course this means varying the projectile speed to meet the target. Does anyone have any tips for a simple-ish algorithm (optimal-ish) to calculate when the projectile needs to fire and where it needs to aim if it can only travel at a constant velocity? Say the projectile goes twice the speed of the target? The only way I can think of involves searching and seems quite large.

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  • Optimizing Jaro-Winkler algorithm

    - by Pentium10
    I have this code for Jaro-Winkler algorithm taken from this website. I need to run 150,000 times to get distance between differences. It takes a long time, as I run on an Android mobile device. Can it be optimized more? public class Jaro { /** * gets the similarity of the two strings using Jaro distance. * * @param string1 the first input string * @param string2 the second input string * @return a value between 0-1 of the similarity */ public float getSimilarity(final String string1, final String string2) { //get half the length of the string rounded up - (this is the distance used for acceptable transpositions) final int halflen = ((Math.min(string1.length(), string2.length())) / 2) + ((Math.min(string1.length(), string2.length())) % 2); //get common characters final StringBuffer common1 = getCommonCharacters(string1, string2, halflen); final StringBuffer common2 = getCommonCharacters(string2, string1, halflen); //check for zero in common if (common1.length() == 0 || common2.length() == 0) { return 0.0f; } //check for same length common strings returning 0.0f is not the same if (common1.length() != common2.length()) { return 0.0f; } //get the number of transpositions int transpositions = 0; int n=common1.length(); for (int i = 0; i < n; i++) { if (common1.charAt(i) != common2.charAt(i)) transpositions++; } transpositions /= 2.0f; //calculate jaro metric return (common1.length() / ((float) string1.length()) + common2.length() / ((float) string2.length()) + (common1.length() - transpositions) / ((float) common1.length())) / 3.0f; } /** * returns a string buffer of characters from string1 within string2 if they are of a given * distance seperation from the position in string1. * * @param string1 * @param string2 * @param distanceSep * @return a string buffer of characters from string1 within string2 if they are of a given * distance seperation from the position in string1 */ private static StringBuffer getCommonCharacters(final String string1, final String string2, final int distanceSep) { //create a return buffer of characters final StringBuffer returnCommons = new StringBuffer(); //create a copy of string2 for processing final StringBuffer copy = new StringBuffer(string2); //iterate over string1 int n=string1.length(); int m=string2.length(); for (int i = 0; i < n; i++) { final char ch = string1.charAt(i); //set boolean for quick loop exit if found boolean foundIt = false; //compare char with range of characters to either side for (int j = Math.max(0, i - distanceSep); !foundIt && j < Math.min(i + distanceSep, m - 1); j++) { //check if found if (copy.charAt(j) == ch) { foundIt = true; //append character found returnCommons.append(ch); //alter copied string2 for processing copy.setCharAt(j, (char)0); } } } return returnCommons; } } I mention that in the whole process I make just instance of the script, so only once jaro= new Jaro(); If you are going to test and need examples so not break the script, you will find it here, in another thread for python optimization.

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  • How to have struct members accessible in different ways

    - by Paul J. Lucas
    I want to have a structure token that has start/end pairs for position, sentence, and paragraph information. I also want the members to be accessible in two different ways: as a start/end pair and individually. Given: struct token { struct start_end { int start; int end; }; start_end pos; start_end sent; start_end para; typedef start_end token::*start_end_ptr; }; I can write a function, say distance(), that computes the distance between any of the three start/end pairs like: int distance( token const &i, token const &j, token::start_end_ptr mbr ) { return (j.*mbr).start - (i.*mbr).end; } and call it like: token i, j; int d = distance( i, j, &token::pos ); that will return the distance of the pos pair. But I can also pass &token::sent or &token::para and it does what I want. Hence, the function is flexible. However, now I also want to write a function, say max(), that computes the maximum value of all the pos.start or all the pos.end or all the sent.start, etc. If I add: typedef int token::start_end::*int_ptr; I can write the function like: int max( list<token> const &l, token::int_ptr p ) { int m = numeric_limits<int>::min(); for ( list<token>::const_iterator i = l.begin(); i != l.end(); ++i ) { int n = (*i).pos.*p; // NOT WHAT I WANT: It hard-codes 'pos' if ( n > m ) m = n; } return m; } and call it like: list<token> l; l.push_back( i ); l.push_back( j ); int m = max( l, &token::start_end::start ); However, as indicated in the comment above, I do not want to hard-code pos. I want the flexibility of accessible the start or end of any of pos, sent, or para that will be passed as a parameter to max(). I've tried several things to get this to work (tried using unions, anonymous unions, etc.) but I can't come up with a data structure that allows the flexibility both ways while having each value stored only once. Any ideas how to organize the token struct so I can have what I want? Attempt at clarification Given struct of pairs of integers, I want to be able to "slice" the data in two distinct ways: By passing a pointer-to-member of a particular start/end pair so that the called function operates on any pair without knowing which pair. The caller decides which pair. By passing a pointer-to-member of a particular int (i.e., only one int of any pair) so that the called function operates on any int without knowing either which int or which pair said int is from. The caller decides which int of which pair. Another example for the latter would be to sum, say, all para.end or all sent.start. Also, and importantly: for #2 above, I'd ideally like to pass only a single pointer-to-member to reduce the burden on the caller. Hence, me trying to figure something out using unions.

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  • C# slowdown while creating a bitmap - calculating distances from a large List of places for each pixel

    - by user576849
    I'm creating a graphic of the glow of lights above a geographic location based upon Walkers Law: Skyglow=0.01*Population*DistanceFromCenter^-2.5 I have a CSV file of places with 66,000 records using 5 fields (id,name,population,latitude,longitude), parsed on the FormLoad event and stored it in: List<string[]> placeDataList Then I set up nested loops to fill in a bitmap using SetPixel. For each pixel on the bitmap, which represents a coordinate on a map (latitude and longitude), the program loops through placeDataList – calculating the distance from that coordinate (pixel) to each place record. The distance (along with population) is used in a calculation to find how much cumulative sky glow is contributed to the coordinate from each place record. So, for every pixel, 66,000 distance calculations must be made. The problem is, this is predictably EXTREMELY slow – on the order of one line of pixels per 30 seconds or so on a 320 pixel wide image. This is unrelated to SetPixel, which I know is also slow, because the speed is similarly slow when adding the distance calculation results to an array. I don’t actually need to test all 66,000 records for every pixel, only the records within 150 miles (i.e. no skyglow is contributed to a coordinate from a small town 3000 miles away). But to find which records are within 150 miles of my coordinate I would still need to loop through all the records for each pixel. I can't use a smaller number of records because all 66,000 places contribute to skyglow for SOME coordinate in my map as it loops. This seems like a Catch-22, so I know there must be a better method out there. Like I mentioned, the slowdown is related to how many calculations I’m making per pixel, not anything to do with the bitmap. Any suggestions? private void fillPixels(int width) { Color pixelColor; int pixel_w = width; int pixel_h = (int)Math.Floor((width * 0.424088664)); Bitmap bmp = new Bitmap(pixel_w, pixel_h); for (int i = 0; i < pixel_h; i++) for (int j = 0; j < pixel_w; j++) { pixelColor = getPixelColor(i, j); bmp.SetPixel(j, i, pixelColor); } bmp.Save("Nightfall", System.Drawing.Imaging.ImageFormat.Jpeg); pictureBox1.Image = bmp; MessageBox.Show("Done"); } private Color getPixelColor(int height, int width) { int c; double glow,d,cityLat,cityLon,cityPop; double testLat, testLon; int size_h = (int)Math.Floor((size_w * 0.424088664)); ; testLat = (height * (24.443136 / size_h)) + 24.548874; testLon = (width * (57.636853 / size_w)) -124.640767; glow = 0; for (int i = 0; i < placeDataList.Count; i++) { cityPop=Convert.ToDouble(placeDataList[i][2]); cityLat=Convert.ToDouble(placeDataList[i][3]); cityLon=Convert.ToDouble(placeDataList[i][4]); d = distance(testLat, testLon, cityLat, cityLon,"M"); if(d<150) glow = glow+(0.01 * cityPop * Math.Pow(d, -2.5)); } if (glow >= 1) glow=1; c = (int)Math.Ceiling(glow * 255); return Color.FromArgb(c, c, c); }

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  • creating objects from trivial graph format text file. java. dijkstra algorithm.

    - by user560084
    i want to create objects, vertex and edge, from trivial graph format txt file. one of programmers here suggested that i use trivial graph format to store data for dijkstra algorithm. the problem is that at the moment all the information, e.g., weight, links, is in the sourcecode. i want to have a separate text file for that and read it into the program. i thought about using a code for scanning through the text file by using scanner. but i am not quite sure how to create different objects from the same file. could i have some help please? the file is v0 Harrisburg v1 Baltimore v2 Washington v3 Philadelphia v4 Binghamton v5 Allentown v6 New York # v0 v1 79.83 v0 v5 81.15 v1 v0 79.75 v1 v2 39.42 v1 v3 103.00 v2 v1 38.65 v3 v1 102.53 v3 v5 61.44 v3 v6 96.79 v4 v5 133.04 v5 v0 81.77 v5 v3 62.05 v5 v4 134.47 v5 v6 91.63 v6 v3 97.24 v6 v5 87.94 and the dijkstra algorithm code is Downloaded from: http://en.literateprograms.org/Special:Downloadcode/Dijkstra%27s_algorithm_%28Java%29 */ import java.util.PriorityQueue; import java.util.List; import java.util.ArrayList; import java.util.Collections; class Vertex implements Comparable<Vertex> { public final String name; public Edge[] adjacencies; public double minDistance = Double.POSITIVE_INFINITY; public Vertex previous; public Vertex(String argName) { name = argName; } public String toString() { return name; } public int compareTo(Vertex other) { return Double.compare(minDistance, other.minDistance); } } class Edge { public final Vertex target; public final double weight; public Edge(Vertex argTarget, double argWeight) { target = argTarget; weight = argWeight; } } public class Dijkstra { public static void computePaths(Vertex source) { source.minDistance = 0.; PriorityQueue<Vertex> vertexQueue = new PriorityQueue<Vertex>(); vertexQueue.add(source); while (!vertexQueue.isEmpty()) { Vertex u = vertexQueue.poll(); // Visit each edge exiting u for (Edge e : u.adjacencies) { Vertex v = e.target; double weight = e.weight; double distanceThroughU = u.minDistance + weight; if (distanceThroughU < v.minDistance) { vertexQueue.remove(v); v.minDistance = distanceThroughU ; v.previous = u; vertexQueue.add(v); } } } } public static List<Vertex> getShortestPathTo(Vertex target) { List<Vertex> path = new ArrayList<Vertex>(); for (Vertex vertex = target; vertex != null; vertex = vertex.previous) path.add(vertex); Collections.reverse(path); return path; } public static void main(String[] args) { Vertex v0 = new Vertex("Nottinghill_Gate"); Vertex v1 = new Vertex("High_Street_kensignton"); Vertex v2 = new Vertex("Glouchester_Road"); Vertex v3 = new Vertex("South_Kensignton"); Vertex v4 = new Vertex("Sloane_Square"); Vertex v5 = new Vertex("Victoria"); Vertex v6 = new Vertex("Westminster"); v0.adjacencies = new Edge[]{new Edge(v1, 79.83), new Edge(v6, 97.24)}; v1.adjacencies = new Edge[]{new Edge(v2, 39.42), new Edge(v0, 79.83)}; v2.adjacencies = new Edge[]{new Edge(v3, 38.65), new Edge(v1, 39.42)}; v3.adjacencies = new Edge[]{new Edge(v4, 102.53), new Edge(v2, 38.65)}; v4.adjacencies = new Edge[]{new Edge(v5, 133.04), new Edge(v3, 102.53)}; v5.adjacencies = new Edge[]{new Edge(v6, 81.77), new Edge(v4, 133.04)}; v6.adjacencies = new Edge[]{new Edge(v0, 97.24), new Edge(v5, 81.77)}; Vertex[] vertices = { v0, v1, v2, v3, v4, v5, v6 }; computePaths(v0); for (Vertex v : vertices) { System.out.println("Distance to " + v + ": " + v.minDistance); List<Vertex> path = getShortestPathTo(v); System.out.println("Path: " + path); } } } and the code for scanning file is import java.util.Scanner; import java.io.File; import java.io.FileNotFoundException; public class DataScanner1 { //private int total = 0; //private int distance = 0; private String vector; private String stations; private double [] Edge = new double []; /*public int getTotal(){ return total; } */ /* public void getMenuInput(){ KeyboardInput in = new KeyboardInput; System.out.println("Enter the destination? "); String val = in.readString(); return val; } */ public void readFile(String fileName) { try { Scanner scanner = new Scanner(new File(fileName)); scanner.useDelimiter (System.getProperty("line.separator")); while (scanner.hasNext()) { parseLine(scanner.next()); } scanner.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } } public void parseLine(String line) { Scanner lineScanner = new Scanner(line); lineScanner.useDelimiter("\\s*,\\s*"); vector = lineScanner.next(); stations = lineScanner.next(); System.out.println("The current station is " + vector + " and the destination to the next station is " + stations + "."); //total += distance; //System.out.println("The total distance is " + total); } public static void main(String[] args) { /* if (args.length != 1) { System.err.println("usage: java TextScanner2" + "file location"); System.exit(0); } */ DataScanner1 scanner = new DataScanner1(); scanner.readFile(args[0]); //int total =+ distance; //System.out.println(""); //System.out.println("The total distance is " + scanner.getTotal()); } }

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  • Fragment Shader Eye-Space unscaled depth coordinate

    - by Ben Jones
    I'm trying to use the unscaled (true distance from the front clipping plane) distance to objects in my scene in a GLSL fragment shader. The gl_FragCoord.z value is smaller than I expect. In my vertex shader, I just use ftransform() to set gl_Position. I'm seeing values between 2 and 3 when I expect them to be between 15 and 20. How can I get the real eye-space depth? Thanks!

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