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  • Can't get Jacobi algorithm to work in Objective-C

    - by Chris Long
    Hi, For some reason, I can't get this program to work. I've had other CS majors look at it and they can't figure it out either. This program performs the Jacobi algorithm (you can see step-by-step instructions and a MATLAB implementation here). BTW, it's different from the Wikipedia article of the same name. Since NSArray is one-dimensional, I added a method that makes it act like a two-dimensional C array. After running the Jacobi algorithm many times, the diagonal entries in the NSArray (i[0][0], i[1][1], etc.) are supposed to get bigger and the others approach 0. For some reason though, they all increase exponentially. For instance, i[2][4] should equal 0.0000009, not 9999999, while i[2][2] should be big. Thanks in advance, Chris NSArray+Matrix.m @implementation NSArray (Matrix) @dynamic offValue, transposed; - (double)offValue { double sum = 0.0; for ( MatrixItem *item in self ) if ( item.nonDiagonal ) sum += pow( item.value, 2.0 ); return sum; } - (NSMutableArray *)transposed { NSMutableArray *transpose = [[[NSMutableArray alloc] init] autorelease]; int i, j; for ( i = 0; i < 5; i++ ) { for ( j = 0; j < 5; j++ ) { [transpose addObject:[self objectAtRow:j andColumn:i]]; } } return transpose; } - (id)objectAtRow:(NSUInteger)row andColumn:(NSUInteger)column { NSUInteger index = 5 * row + column; return [self objectAtIndex:index]; } - (NSMutableArray *)multiplyWithMatrix:(NSArray *)array { NSMutableArray *result = [[NSMutableArray alloc] init]; int i = 0, j = 0, k = 0; double value; for ( i = 0; i < 5; i++ ) { value = 0.0; for ( j = 0; j < 5; j++ ) { for ( k = 0; k < 5; k++ ) { MatrixItem *firstItem = [self objectAtRow:i andColumn:k]; MatrixItem *secondItem = [array objectAtRow:k andColumn:j]; value += firstItem.value * secondItem.value; } MatrixItem *item = [[MatrixItem alloc] initWithValue:value]; item.row = i; item.column = j; [result addObject:item]; } } return result; } @end Jacobi_AlgorithmAppDelegate.m // ... - (void)jacobiAlgorithmWithEntry:(MatrixItem *)entry { MatrixItem *b11 = [matrix objectAtRow:entry.row andColumn:entry.row]; MatrixItem *b22 = [matrix objectAtRow:entry.column andColumn:entry.column]; double muPlus = ( b22.value + b11.value ) / 2.0; muPlus += sqrt( pow((b22.value - b11.value), 2.0) + 4.0 * pow(entry.value, 2.0) ); Vector *u1 = [[[Vector alloc] initWithX:(-1.0 * entry.value) andY:(b11.value - muPlus)] autorelease]; [u1 normalize]; Vector *u2 = [[[Vector alloc] initWithX:-u1.y andY:u1.x] autorelease]; NSMutableArray *g = [[[NSMutableArray alloc] init] autorelease]; for ( int i = 0; i <= 24; i++ ) { MatrixItem *item = [[[MatrixItem alloc] init] autorelease]; if ( i == 6*entry.row ) item.value = u1.x; else if ( i == 6*entry.column ) item.value = u2.y; else if ( i == ( 5*entry.row + entry.column ) || i == ( 5*entry.column + entry.row ) ) item.value = u1.y; else if ( i % 6 == 0 ) item.value = 1.0; else item.value = 0.0; [g addObject:item]; } NSMutableArray *firstResult = [[g.transposed multiplyWithMatrix:matrix] autorelease]; matrix = [firstResult multiplyWithMatrix:g]; } // ...

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  • c++ protected pointer member to the same class and access privileges

    - by aajmakin
    Hi, Example code is included at the bottom of the message. I'm puzzled about the protected access specifier in a class. I have define a class node which has a protected string member name string name; and a vector of node pointers vector args; Before I thought that a member function of node could not do args[0]-name but a program that does just this does compile and run. However, now I would like to inherit this class and access the name field in one of the args array pointers from this derived class args[0]-name but this does not compile. When I compile the example code below with the commented sections uncommented, the compiler reports: Compiler output: g++ test.cc -o test test.cc: In member function 'void foo::newnode::print_args2()': test.cc:22: error: 'std::string foo::node::name' is protected test.cc:61: error: within this context Compilation exited abnormally with code 1 at Thu Jun 17 12:40:12 Questions: Why can I access the name field of the node pointers in args in class node, because this is what I would excpect from a similarly defined private field in Java. How can I access those fields from the derived class. Example code: #include <iostream> #include <vector> using namespace std; namespace foo { class node; typedef std::vector<node*> nodes; class node { public: node (string _name); void print_args (); void add_node (node* a); protected: nodes args; string name; }; } foo::node::node (string _name) : args(0) { name = _name; } void foo::node::add_node (node* a) { args.push_back(a); } void foo::node::print_args () { for (int i = 0; i < args.size(); i++) { cout << "node " << i << ": " << args[i]->name << endl; } } // namespace foo // { // class newnode : public node // { // public: // newnode (string _name) : node(_name) {} // void print_args2 (); // protected: // }; // } // void foo::newnode::print_args2 () // { // for (int i = 0; i < args.size(); i++) // { // cout << "node " << i << ": " << args[i]->name << endl; // } // } int main (int argc, char** argv) { foo::node a ("a"); foo::node b ("b"); foo::node c ("c"); a.add_node (&b); a.add_node (&c); a.print_args (); // foo::newnode newa ("newa"); // foo::newnode newb ("newb"); // foo::newnode newc ("newc"); // newa.add_node (&newb); // newa.add_node (&newc); // newa.print_args2 (); return 0; }

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  • C++ Problem resolution - is it the best way to simulate a "tuple"?

    - by fbin
    Hi everyone! I've got the following problem: "Write a template function vectorMAXMIN() that will accept a vector and a number indicating the size of the vector and will return the max and the min values of the vector"... So i think in it... Create a class vector to avoid the "size" passing value and control the insertions and can get from this the max and min values... ( dunno if it's a good idea ) The problem is "how to return a tuple?" When i read the problem, i thought in a tuple to return "max, min values" is it correct? The code: #include <iostream> template < typename T > class _tuple { public: T _Max; T _Min; }; template < typename T > class _vector { public: _vector( int cnt = 0); ~_vector(); _tuple< T > get_tuple( void ); void insert( const T ); private: T *ptr; int cnt; int MAX; }; template < typename T > _vector< T >::_vector( int N ) { ptr = new T [N] ; MAX = N; cnt = 0; } template < typename T > _tuple<T> _vector< T >::get_tuple( void ) { _tuple< T > _mytuple; _mytuple._Max = ptr[0]; _mytuple._Min = ptr[0]; for( int i = 1; i < cnt; i++) { if( _mytuple._Max > ptr[i] ) _mytuple._Max = ptr[i]; if( _mytuple._Min < ptr[i] ) _mytuple._Min = ptr[i]; } return _mytuple; } template < typename T > void _vector< T >::insert( const T element) { if( cnt == MAX ) std::cerr << "Error: Out of range!" << std::endl; else { ptr[cnt] = element; cnt++; } } template < typename T > _vector< T >::~_vector() { delete [] ptr; } int main() { _vector< int > v; _tuple < int > t; v.insert(2); v.insert(1); v.insert(5); v.insert(0); v.insert(4); t = v.get_tuple(); std::cout << "MAX:" << t._Max; std::cout << " MIN:" << t._Min; return 0; }

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  • Referencing variables in a structure / C++

    - by user1628622
    Below, I provided a minimal example of code I created. I managed to get this code working, but I'm not sure if the practice being employed is sound. In essence, what I am trying to do is have the 'Parameter' class reference select elements in the 'States' class, so variables in States can be changed via Parameters. Questions I have: is the approach taken OK? If not, is there a better way to achieve what I am aiming for? Example code: struct VAR_TYPE{ public: bool is_fixed; // If is_fixed = true, then variable is a parameter double value; // Numerical value std::string name; // Description of variable (to identify it by name) }; struct NODE{ public: VAR_TYPE X, Y, Z; /* VAR_TYPE is a structure of primitive types */ }; class States{ private: std::vector <NODE_ptr> node; // shared ptr to struct NODE std::vector <PROP_DICTIONARY_ptr> property; // CAN NOT be part of Parameter std::vector <ELEMENT_ptr> element; // CAN NOT be part of Parameter public: /* ect */ void set_X_reference ( Parameter &T , int i ) { T.push_var( &node[i]->X ); } void set_Y_reference ( Parameter &T , int i ) { T.push_var( &node[i]->Y ); } void set_Z_reference ( Parameter &T , int i ) { T.push_var( &node[i]->Z ); } bool get_node_bool_X( int i ) { return node[i]->X.is_fixed; } // repeat for Y and Z }; class Parameter{ private: std::vector <VAR_TYPE*> var; public: /* ect */ }; int main(){ States S; Parameter P; /* Here I initialize and set S, and do other stuff */ // Now I assign components in States to Parameters for(int n=0 ; n<S.size_of_nodes() ; n++ ){ if ( S.get_node_bool_X(n)==true ){ S.set_X_reference ( P , n ); }; // repeat if statement for Y and Z }; /* Now P points selected to data in S, and I can * modify the contents of S through P */ return 0; }; Update The reason this issue cropped up is I am working with Fortran legacy code. To sum up this Fotran code - it's a numerical simulation of a flight vehicle. This code has a fairly rigid procedural framework one must work within, which comes with a pre-defined list of allowable Fortran types. The Fortran glue code can create an instance of a C++ object (in actuality, a reference from the perspective of Fortran), but is not aware what is contained in it (other means are used to extract C++ data into Fortran). The problem that I encountered is when a C++ module is dynamically linked to the Fortran glue code, C++ objects have to be initialized each instance the C++ code is called. This happens by virtue of how the Fortran template is defined. To avoid this cycle of re-initializing objects, I plan to use 'State' as a container class. The Fortran code allows a 'State' object, which has an arbitrary definition; but I plan to use it to harness all relevant information about the model. The idea is to use the Parameters class (which is exposed and updated by the Fortran code) to update variables in States.

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  • SFML: Generate a background image

    - by BlackMamba
    I want to generate a background, which is used in the game, on every instance of the game based on certain conditions. To do so, I'm using a sf::RenderTexture and a sf::Texture like this: sf::RenderTexture image; std::vector<sf::Texture> textures; sf::Texture texture; // instantiating the vector of textures and the image not shown here for (int i = 0; i < certainSize; ++i) { if(certainContition) { texture.setTexture("file"); texture.setPosition(pos1, pos2); } else { ... } image.draw(texture); } The point here is that I draw single textures on a sf::RenderTexture, but because textures always are on the graphic cards memory, I can't exceed a certain map size which I have to. I also considered using an sf::Image, but I can't find a way to draw an image (i.e. a texture) to it. The third way I found was using an sf::VertexArray, but this seems to be a bit too low-level for my rather simple purposes. So is there a common way to dynamically generate a background image based on other existing images?

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  • cocos2d-x and handling touch events

    - by Jason
    I have my sprites on screen and I have a vector that stores each sprite. Can a CCSprite* handle a touch event? Or just the CCLayer*? What is the best way to decide what sprite was touched? Should I store the coordinates of where the sprite is (in the sprite class) and when I get the event, see if where the user touched is where the sprite is by looking through the vector and getting each sprites current coordinates? UPDATE: I subclass CCSprite: class Field : public cocos2d::CCSprite, public cocos2d::CCTargetedTouchDelegate and I implement functions: cocos2d::CCRect rect(); virtual void onEnter(); virtual void onExit(); bool containsTouchLocation(cocos2d::CCTouch* touch); virtual bool ccTouchBegan(cocos2d::CCTouch* touch, cocos2d::CCEvent* event); virtual void ccTouchMoved(cocos2d::CCTouch* touch, cocos2d::CCEvent* event); virtual void ccTouchEnded(cocos2d::CCTouch* touch, cocos2d::CCEvent* event); virtual void touchDelegateRetain(); virtual void touchDelegateRelease(); I put CCLOG statements in each one and I dont hit them! When I touch the CCLayer this sprite is on though I do hit those in the class that implements the Layer and puts these sprites on the layer.

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  • Transforming object world space matrix to a position in world space

    - by Fredrik Boston Westman
    Im trying to make a function for picking objects with a bounding sphere however I have run in to a problem. First I check against my my bounding sphere, then if it checks out then I test against the vertexes. I have already tested my vertex picking method and it work fine, however when I check first with my bounding sphere method it dosnt register anything. My conclusion is that when im transform my sphere position in to the position of the object in world space, the transformation goes wrong ( I base this on the fact the the x coordinate always becomes 1, even tho i translate non of my meshes along the x-axis to 1). So my question is: What is the proper way to transform a objects world space matrix to a position vector ? This is how i do it now: First i set my position vector to 0. XMVECTOR meshPos = XMVectorSet(0.0f, 0.0f, 0.0f, 0.0f); Then I trannsform it with my object space matrix, and then add the offset to the center of the mesh. meshPos = XMVector3TransformCoord(meshPos, meshWorld) + centerOffset;

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  • box2d tween what am I missing

    - by philipp
    I have a Box2D project and I want to tween an kinematic body from position A, to position B. The tween function, got it from this blog: function easeInOut(t , b, c, d ){ if ( ( t /= d / 2 ) < 1){ return c/2 * t * t * t * t + b; } return -c/2 * ( (t -= 2 ) * t * t * t - 2 ) + b; } where t is the current value, b the start, c the end and d the total amount of frames (in my case). I am using the method introduced by this lesson of todd's b2d tutorials to move the body by setting its linear Velocity so here is relevant update code of the sprite: if( moveData.current == moveData.total ){ this._body.SetLinearVelocity( new b2Vec2() ); return; } var t = easeNone( moveData.current, 0, 1, moveData.total ); var step = moveData.length / moveData.total * t; var dir = moveData.direction.Copy(); //this is the line that I think might be corrected dir.Multiply( t * moveData.length * fps /moveData.total ) ; var bodyPosition = this._body.GetWorldCenter(); var idealPosition = bodyPosition.Copy(); idealPosition.Add( dir ); idealPosition.Subtract( bodyPosition.Copy() ); moveData.current++; this._body.SetLinearVelocity( idealPosition ); moveData is an Object that holds the global values of the tween, namely: current frame (int), total frames (int), the length of the total distance to travel (float) the direction vector (targetposition - bodyposition) (b2Vec2) and the start of the tween (bodyposition) (b2Vec2) Goal is to tween the body based on a fixed amount of frames: in moveData.total frames. The value of t is always between 0 and 1 and the only thing that is not working correctly is the resulting distance the body travels. I need to calculate the multiplier for the direction vector. What am I missing to make it work?? Greetings philipp

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  • Game Over function is not working Starling

    - by aNgeLyN omar
    I've been following a tutorial over the web but it somehow did not show something about creating a game over function. I am new to the Starling framework and Actionscript so I'm kind of still trying to find a way to make it work. Here's the complete snippet of the code. package screens { import flash.geom.Rectangle; import flash.utils.getTimer; import events.NavigationEvent; import objects.GameBackground; import objects.Hero; import objects.Item; import objects.Obstacle; import starling.display.Button; import starling.display.Image; import starling.display.Sprite; import starling.events.Event; import starling.events.Touch; import starling.events.TouchEvent; import starling.text.TextField; import starling.utils.deg2rad; public class InGame extends Sprite { private var screenInGame:InGame; private var screenWelcome:Welcome; private var startButton:Button; private var playAgain:Button; private var bg:GameBackground; private var hero:Hero; private var timePrevious:Number; private var timeCurrent:Number; private var elapsed:Number; private var gameState:String; private var playerSpeed:Number = 0; private var hitObstacle:Number = 0; private const MIN_SPEED:Number = 650; private var scoreDistance:int; private var obstacleGapCount:int; private var gameArea:Rectangle; private var touch:Touch; private var touchX:Number; private var touchY:Number; private var obstaclesToAnimate:Vector.<Obstacle>; private var itemsToAnimate:Vector.<Item>; private var scoreText:TextField; private var remainingLives:TextField; private var gameOverText:TextField; private var iconSmall:Image; static private var lives:Number = 2; public function InGame() { super(); this.addEventListener(starling.events.Event.ADDED_TO_STAGE, onAddedToStage); } private function onAddedToStage(event:Event):void { this.removeEventListener(Event.ADDED_TO_STAGE, onAddedToStage); drawGame(); scoreText = new TextField(300, 100, "Score: 0", "MyFontName", 35, 0xD9D919, true); remainingLives = new TextField(600, 100, "Lives: " + lives +" X ", "MyFontName", 35, 0xD9D919, true); iconSmall = new Image(Assets.getAtlas().getTexture("darnahead1")); iconSmall.x = 360; iconSmall.y = 40; this.addChild(iconSmall); this.addChild(scoreText); this.addChild(remainingLives); } private function drawGame():void { bg = new GameBackground(); this.addChild(bg); hero = new Hero(); hero.x = stage.stageHeight / 2; hero.y = stage.stageWidth / 2; this.addChild(hero); startButton = new Button(Assets.getAtlas().getTexture("startButton")); startButton.x = stage.stageWidth * 0.5 - startButton.width * 0.5; startButton.y = stage.stageHeight * 0.5 - startButton.height * 0.5; this.addChild(startButton); gameArea = new Rectangle(0, 100, stage.stageWidth, stage.stageHeight - 250); } public function disposeTemporarily():void { this.visible = false; } public function initialize():void { this.visible = true; this.addEventListener(Event.ENTER_FRAME, checkElapsed); hero.x = -stage.stageWidth; hero.y = stage.stageHeight * 0.5; gameState ="idle"; playerSpeed = 0; hitObstacle = 0; bg.speed = 0; scoreDistance = 0; obstacleGapCount = 0; obstaclesToAnimate = new Vector.<Obstacle>(); itemsToAnimate = new Vector.<Item>(); startButton.addEventListener(Event.TRIGGERED, onStartButtonClick); //var mainStage:InGame =InGame.current.nativeStage; //mainStage.dispatchEvent(new Event(Event.COMPLETE)); //playAgain.addEventListener(Event.TRIGGERED, onRetry); } private function onStartButtonClick(event:Event):void { startButton.visible = false; startButton.removeEventListener(Event.TRIGGERED, onStartButtonClick); launchHero(); } private function launchHero():void { this.addEventListener(TouchEvent.TOUCH, onTouch); this.addEventListener(Event.ENTER_FRAME, onGameTick); } private function onTouch(event:TouchEvent):void { touch = event.getTouch(stage); touchX = touch.globalX; touchY = touch.globalY; } private function onGameTick(event:Event):void { switch(gameState) { case "idle": if(hero.x < stage.stageWidth * 0.5 * 0.5) { hero.x += ((stage.stageWidth * 0.5 * 0.5 + 10) - hero.x) * 0.05; hero.y = stage.stageHeight * 0.5; playerSpeed += (MIN_SPEED - playerSpeed) * 0.05; bg.speed = playerSpeed * elapsed; } else { gameState = "flying"; } break; case "flying": if(hitObstacle <= 0) { hero.y -= (hero.y - touchY) * 0.1; if(-(hero.y - touchY) < 150 && -(hero.y - touchY) > -150) { hero.rotation = deg2rad(-(hero.y - touchY) * 0.2); } if(hero.y > gameArea.bottom - hero.height * 0.5) { hero.y = gameArea.bottom - hero.height * 0.5; hero.rotation = deg2rad(0); } if(hero.y < gameArea.top + hero.height * 0.5) { hero.y = gameArea.top + hero.height * 0.5; hero.rotation = deg2rad(0); } } else { hitObstacle-- cameraShake(); } playerSpeed -= (playerSpeed - MIN_SPEED) * 0.01; bg.speed = playerSpeed * elapsed; scoreDistance += (playerSpeed * elapsed) * 0.1; scoreText.text = "Score: " + scoreDistance; initObstacle(); animateObstacles(); createEggItems(); animateItems(); remainingLives.text = "Lives: "+lives + " X "; if(lives == 0) { gameState = "over"; } break; case "over": gameOver(); break; } } private function gameOver():void { gameOverText = new TextField(800, 400, "Hero WAS KILLED!!!", "MyFontName", 50, 0xD9D919, true); scoreText = new TextField(800, 600, "Score: "+scoreDistance, "MyFontName", 30, 0xFFFFFF, true); this.addChild(scoreText); this.addChild(gameOverText); playAgain = new Button(Assets.getAtlas().getTexture("button_tryAgain")); playAgain.x = stage.stageWidth * 0.5 - startButton.width * 0.5; playAgain.y = stage.stageHeight * 0.75 - startButton.height * 0.75; this.addChild(playAgain); playAgain.addEventListener(Event.TRIGGERED, onRetry); } private function onRetry(event:Event):void { playAgain.visible = false; gameOverText.visible = false; scoreText.visible = false; var btnClicked:Button = event.target as Button; if((btnClicked as Button) == playAgain) { this.dispatchEvent(new NavigationEvent(NavigationEvent.CHANGE_SCREEN, {id: "playnow"}, true)); } disposeTemporarily(); } private function animateItems():void { var itemToTrack:Item; for(var i:uint = 0; i < itemsToAnimate.length; i++) { itemToTrack = itemsToAnimate[i]; itemToTrack.x -= playerSpeed * elapsed; if(itemToTrack.bounds.intersects(hero.bounds)) { itemsToAnimate.splice(i, 1); this.removeChild(itemToTrack); } if(itemToTrack.x < -50) { itemsToAnimate.splice(i, 1); this.removeChild(itemToTrack); } } } private function createEggItems():void { if(Math.random() > 0.95){ var itemToTrack:Item = new Item(Math.ceil(Math.random() * 10)); itemToTrack.x = stage.stageWidth + 50; itemToTrack.y = int(Math.random() * (gameArea.bottom - gameArea.top)) + gameArea.top; this.addChild(itemToTrack); itemsToAnimate.push(itemToTrack); } } private function cameraShake():void { if(hitObstacle > 0) { this.x = Math.random() * hitObstacle; this.y = Math.random() * hitObstacle; } else if(x != 0) { this.x = 0; this.y = 0; lives--; } } private function initObstacle():void { if(obstacleGapCount < 1200) { obstacleGapCount += playerSpeed * elapsed; } else if(obstacleGapCount !=0) { obstacleGapCount = 0; createObstacle(Math.ceil(Math.random() * 5), Math.random() * 1000 + 1000); } } private function animateObstacles():void { var obstacleToTrack:Obstacle; for(var i:uint = 0; i<obstaclesToAnimate.length; i++) { obstacleToTrack = obstaclesToAnimate[i]; if(obstacleToTrack.alreadyHit == false && obstacleToTrack.bounds.intersects(hero.bounds)) { obstacleToTrack.alreadyHit = true; obstacleToTrack.rotation = deg2rad(70); hitObstacle = 30; playerSpeed *= 0.5; } if(obstacleToTrack.distance > 0) { obstacleToTrack.distance -= playerSpeed * elapsed; } else { if(obstacleToTrack.watchOut) { obstacleToTrack.watchOut = false; } obstacleToTrack.x -= (playerSpeed + obstacleToTrack.speed) * elapsed; } if(obstacleToTrack.x < -obstacleToTrack.width || gameState == "over") { obstaclesToAnimate.splice(i, 1); this.removeChild(obstacleToTrack); } } } private function checkElapsed(event:Event):void { timePrevious = timeCurrent; timeCurrent = getTimer(); elapsed = (timeCurrent - timePrevious) * 0.001; } private function createObstacle(type:Number, distance:Number):void{ var obstacle:Obstacle = new Obstacle(type, distance, true, 300); obstacle.x = stage.stageWidth; this.addChild(obstacle); if(type >= 4) { if(Math.random() > 0.5) { obstacle.y = gameArea.top; obstacle.position = "top" } else { obstacle.y = gameArea.bottom - obstacle.height; obstacle.position = "bottom"; } } else { obstacle.y = int(Math.random() * (gameArea.bottom - obstacle.height - gameArea.top)) + gameArea.top; obstacle.position = "middle"; } obstaclesToAnimate.push(obstacle); } } }

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  • Mixing XNA and silverlight gives wierd graphics

    - by Mech0z
    I making a small 3dgame which is made as a Silverlight and XNA app, but when I draw the sprites the graphics becomes all wierd. All my primitive types are rendered correctly, but my 3d models are just wierd My Draw is like this when silverlight is set to draw private void OnDraw(object sender, GameTimerEventArgs e) { // Render the Silverlight controls using the UIElementRenderer elementRenderer.Render(); // Clear the screen to a solid color SharedGraphicsDeviceManager.Current.GraphicsDevice.Clear(Color.CornflowerBlue); switch (gameState) { case GameState.ChooseStarter: TextBlockStatus.Text = "Find Starting Player"; break; case GameState.PlaceBrick: TextBlockPlayer.Text = (playerTurn == PlayerTurn.PlayerOne) ? "Player One" : "Player Two"; TextBlockState.Text = "Place Brick"; foreach (IGraphicObject obj in _3dObjects) { obj.Draw(cameraPosition, e); } break; case GameState.GiveBrick: TextBlockState.Text = "Give Brick"; break; } spriteBatch.Begin(); // Using the texture from the UIElementRenderer, // draw the Silverlight controls to the screen spriteBatch.Draw(elementRenderer.Texture, cameraProjection, Color.White); spriteBatch.End(); } This gives me this output If I comment the spritebatch lines out I get the correct output, except the silverlight text is of course not shown I am not entirely sure what to look for except that zero vector I am giving to the spritebatch, but if thats the source I have no idea what I am supposed to set it as epspecially when its a 2d vector

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  • Why isn't my lighting working properly? Are my normals messed up?

    - by Radek Slupik
    I'm relatively new to OpenGL and I am trying to draw a 3D model (loaded from a 3ds file using lib3ds) using OpenGL with lighting, but about half of it is drawn in black. I set up the light as such: glEnable(GL_LIGHTING); glShadeModel(GL_SMOOTH); GLfloat ambientColor[] = {0.2f, 0.2f, 0.2f, 1.0f}; glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambientColor); glEnable(GL_LIGHT0); GLfloat lightColor0[] = {1.0f, 1.0f, 1.0f, 1.0f}; GLfloat lightPos0[] = {4.0f, 0.0f, 8.0f, 0.0f}; glLightfv(GL_LIGHT0, GL_DIFFUSE, lightColor0); glLightfv(GL_LIGHT0, GL_POSITION, lightPos0); The model is in a VBO and drawn using glDrawArrays. The normals are in a separate VBO, and the normals are calculated using lib3ds_mesh_calculate_vertex_normals: std::vector<std::array<float, 3>> normals; for (std::size_t i = 0; i < model->nmeshes; ++i) { auto& mesh = *model->meshes[i]; std::vector<float[3]> vertex_normals(mesh.nfaces * 3); lib3ds_mesh_calculate_vertex_normals(&mesh, vertex_normals.data()); for (std::size_t j = 0; j < mesh.nfaces; ++j) { auto& face = mesh.faces[j]; normals.push_back(make_array(vertex_normals[j])); } } glBindBuffer(GL_ARRAY_BUFFER, normal_vbo_); glBufferData(GL_ARRAY_BUFFER, normals.size() * sizeof(decltype(normals)::value_type), normals.data(), GL_STATIC_DRAW); The problem isn't the vertices; the model is drawn correctly when drawing it as a wireframe. I also fixed the normals in Blender using controlN. What could be the problem? Should I store the normals in a different order?

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  • How important do you find exception safety to be in your C++ code?

    - by Kai
    Every time I consider making my code strongly exception safe, I justify not doing it because it would be so time consuming. Consider this relatively simple snippet: Level::Entity* entity = new Level::Entity(); entity->id = GetNextId(); entity->AddComponent(new Component::Position(x, y)); entity->AddComponent(new Component::Movement()); entity->AddComponent(new Component::Render()); allEntities.push_back(entity); // std::vector entityById[entity->id] = entity; // std::map return entity; To implement a basic exception guarantee, I could use a scoped pointer on the new calls. This would prevent memory leaks if any of the calls were to throw an exception. However, let's say I want to implement a strong exception guarantee. At the least, I would need to implement a shared pointer for my containers (I'm not using Boost), a nothrow Entity::Swap for adding the components atomically, and some sort of idiom for atomically adding to both the Vector and Map. Not only would these be time consuming to implement, but they would be expensive since it involves a lot more copying than the exception unsafe solution. Ultimately, it feels to me like that time spent doing all of that wouldn't be justified just so that the a simple CreateEntity function is strongly exception safe. I probably just want the game to display an error and close at that point anyway. How far do you take this in your own game projects? Is it generally acceptable to write exception unsafe code for a program that can just crash when there is an exception?

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  • Missing z-axis rotation for transforming between two vectors

    - by Steve Baughman
    I'm trying to rotate a cube so that it's facing up, but am getting hung up on the final implementation details. It now reliably will rotate the x,y axis to the correct side, but the z-axis is never rotating (See photos of before and after rotation). When I'm using the code below I always get '0' for my rotationVector.z. What am I missing here? // Define lookAt vector lookAtVector = GLKVector3Make(0,0,1); // Define axes vectors axes[0] = GLKVector3Make(0,0,1); axes[1] = GLKVector3Make(-1,0,0); axes[2] = GLKVector3Make(0,1,0); axes[3] = GLKVector3Make(1,0,0); axes[4] = GLKVector3Make(0,-1,0); axes[5] = GLKVector3Make(0,0,-1); CGFloat highest_dot = -1.0; GLKVector3 closest_axis; for(int i = 0; i < 6; i++) { // multiply cube's axes by existing matrix GLKVector3 axis = GLKMatrix4MultiplyVector3(matrix, axes[i]); CGFloat dot = GLKVector3DotProduct(axis, lookAtVector); if(dot > highest_dot) { closest_axis = axis; highest_dot = dot; } } GLKVector3 rotationVector = GLKVector3CrossProduct(closest_axis, lookAtVector); // Get angle between vectors CGFloat angle = atan2(GLKVector3Length(rotationVector), GLKVector3DotProduct(closest_axis, lookAtVector)); // normalize the rotation vector rotationVector = GLKVector3Normalize(rotationVector); // Create transform CATransform3D rotationTransform = CATransform3DMakeRotation(angle, rotationVector.x, rotationVector.y, rotationVector.z); // add rotation transform to existing transformation baseTransform = CATransform3DConcat(baseTransform, rotationTransform); return baseTransform; Before 3d Rotation After 3d Rotation Implementation based on this post

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  • call function between classes [closed]

    - by aziz joh
    hello I have 3 classes class A, B, and C class A is the main class and content the main function also, i call class B and class C in the main as b1,b2 and c1. in class B there is a vector (V) has list of int. and 3 functions Add, get and delete delete. all the thing in the class is public. in class C i have function that need to (B::get) from b. what I want is that how I can make c1 call get of b1 to return the value of the V in b1 after that use add of b2 to add new item in V of b2. Thanks in advance This is an example class a{ int main(){ b b1,b2; c c1; b1.add(10); b1.add(20); c1.start(); }} class b{ vector<int> v; void add(int i){ v.push_back(i)} int get(){int i=v.at(0); return i;} } class c{// take something from b1 and add it to b2 void play(){ int i=b.get();//should take it from b1 b.add(i*2);//should add it to b2 }} please I need your help I been searching to solve this problem for days.

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  • How to define type-specific scripts when using a 'type object' programming pattern?

    - by Erik
    I am in the process of creating a game engine written in C++, using the C/C++ SQLite interface to achieve a 'type object' pattern. The process is largely similar to what is outlined here (Thank you Bob Nystrom for the great resource!). I have a generally defined Entity class that when a new object is created, data is taken from a SQLite database and then is pushed back into a pointer vector, which is then iterated through, calling update() for each object. All the ints, floats, strings are loaded in fine, but the script() member of Entity is proving an issue. It's not much fun having a bunch of stationary objects laying around my gameworld. The only solutions I've come up with so far are: Create a monolithic EntityScript class with member functions encompassing all game AI and then calling the corresponding script when iterating through the Entity vector. (Not ideal) Create bindings between C++ and a scripting language. This would seem to get the job done, but it feels like implementing this (given the potential memory overhead) and learning a new language is overkill for a small team (2-3 people) that know the entirety of the existing game engine. Can you suggest any possible alternatives? My ideal situation would be that to add content to the game, one would simply add a script file to the appropriate directory and append the SQLite database with all the object data. All that is required is to have a variety of integers and floats passed between both the engine and the script file.

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  • Getting an OBB out of another OBB?

    - by Milo
    I'm working on collision resolution for my game. I just need a good way to get an object out of another object if it gets stuck. In this case a car. Here is a typical scenario. The red car is in the green object. How do I correctly get it out so the car can slide along the edge of the object as it should. I tried: if(buildings.size() > 0) { Entity e = buildings.get(0); Vector2D vel = new Vector2D(); vel.x = vehicle.getVelocity().x; vel.y = vehicle.getVelocity().y; vel.normalize(); while(vehicle.getRect().overlaps(e.getRect())) { vehicle.setCenter(vehicle.getCenterX() - vel.x * 0.1f, vehicle.getCenterY() - vel.y * 0.1f); } colided = true; } But that does not work too well. Is there some sort of vector I could calculate to use as the vector to move the car away from the object? Thanks

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  • Transform coordinates from 3d to 2d without matrix or built in methods

    - by Thomas
    Not to long ago i started to create a small 3D engine in javascript to combine this with an html5 canvas. One of the issues I run into is how can you transform 3d to 2d coords. Since I cannot use matrices or built in transformation methods I need another way. I've tried implementing the next explanation + pseudo code: http://freespace.virgin.net/hugo.elias/routines/3d_to_2d.htm Unfortunately no luck there. I've replace all the input variables with data from my own camera and object classes. I have the following data: An object with a rotation, position vector and an array of 4 3d coords (its just a plane) a camera with a position and rotation vector the viewport - a square 600 x 600 surface. The example uses a zoom factor which I've set as 1 Most hits on google use either matrix calculations or don't implement camera rotation. Basic transformation should be like this: screen.x = x / z * zoom screen.y = y / z * zoom Can anyone point me in the right direction or explain to me howto achieve this? edit: Thanks for all your posts, I haven't been able to apply all this to my project yet but I hope to do this soon.

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  • Can't read .cso files but I can read their .hlsl versions?

    - by Jader J Rivera
    Well I've been trying to read a .cso file to use as a shader for a DirectX program I'm currently making. Problem is no matter how I implemented a way to read the file it never worked. And after fidgeting around I discover that it's only the .cso files I can't read. I can read anything else (which means it works) even their .hlsl files. Which is strange because the .hlsl (high level shader language) files are supposed to turn into .cso (compiled shader object) files. What I'm currently doing is: vector<byte> Read(string File){ vector<byte> Text; fstream file(File, ios::in | ios::ate | ios::binary); if(file.is_open()){ Text.resize(file.tellg()); file.seekg(0 , ios::beg); file.read(reinterpret_cast<char*>(&Text[0]), Text.size()); file.close(); } return Text; }; If I then implement it. Read("VertexShader.hlsl"); //Works Read("VertexShader.cso"); //Doesn't Works?!?! And I need the .cso version of the shader to draw my sexy triangles. Without it my life and application will never continue and I have no idea what could be wrong. (I've also asked this at stack overflow but still no answers.)

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  • Wheel rotation, to change velocity of vehicle

    - by Lewis
    I update the velocity of my vehicle like so: [v setVelocity: ((2 * 3.14 * 100 * (wheel.getRotationValue / 360) / 30)) * gameSpeed]; // update on 60 fps this gets velocity on all frames divide by 60 for 1 frame. This is done in my update method in my world class. Now wheel.getRotationValue returns the rotation value which is worked out like this: - (void)ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; CGPoint location = [touch locationInView:[touch view]]; location = [[CCDirector sharedDirector] convertToGL:location]; if (CGRectContainsPoint(wheel.boundingBox, location)) { CGPoint firstLocation = [touch previousLocationInView:[touch view]]; CGPoint location = [touch locationInView:[touch view]]; CGPoint touchingPoint = [[CCDirector sharedDirector] convertToGL:location]; CGPoint firstTouchingPoint = [[CCDirector sharedDirector] convertToGL:firstLocation]; CGPoint firstVector = ccpSub(firstTouchingPoint, wheel.position); CGFloat firstRotateAngle = -ccpToAngle(firstVector); CGFloat previousTouch = CC_RADIANS_TO_DEGREES(firstRotateAngle); CGPoint vector = ccpSub(touchingPoint, wheel.position); CGFloat rotateAngle = -ccpToAngle(vector); CGFloat currentTouch = CC_RADIANS_TO_DEGREES(rotateAngle); float limit = 0.5; rotationValue += (currentTouch - previousTouch) * limit; } touching = YES; } Say I steer the vehicle to the far right of the screen, and want to move it to the far left, It wont start moving to the left of the screen until the rotationValue is past 0 degrees again (the wheel is in its center posistion) and is dragged past this value. Is there anyway to change the code I have above, so that movement on the wheel is recognised instantly and updates the velocity of v instantly too?

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  • How to use Pixel Bender (pbj) in ActionScript3 on large Vectors to make fast calculations?

    - by Arthur Wulf White
    Remember my old question: 2d game view camera zoom, rotation & offset using 'Filter' / 'Shader' processing? I figured I could use a Pixel Bender Shader to do the computation for any large group of elements in a game to save on processing time. At least it's a theory worth checking. I also read this question: Pass large array to pixel shader Which I'm guessing is about accomplishing the same thing in a different language. I read this tutorial: http://unitzeroone.com/blog/2009/03/18/flash-10-massive-amounts-of-3d-particles-with-alchemy-source-included/ I am attempting to do some tests. Here is some of the code: private const SIZE : int = Math.pow(10, 5); private var testVectorNum : Vector.<Number>; private function testShader():void { shader.data.ab.value = [1.0, 8.0]; shader.data.src.input = testVectorNum; shader.data.src.width = SIZE/400; shader.data.src.height = 100; shaderJob = new ShaderJob(shader, testVectorNum, SIZE / 4, 1); var time : int = getTimer(), i : int = 0; shaderJob.start(true); trace("TEST1 : ", getTimer() - time); } The problem is that I keep getting a error saying: [Fault] exception, information=Error: Error #1000: The system is out of memory. Update: I managed to partially workaround the problem by converting the vector into bitmapData: (Using this technique I still get a speed boost of 3x using Pixel Bender) private function testShader():void { shader.data.ab.value = [1.0, 8.0]; var time : int = getTimer(), i : int = 0; testBitmapData.setVector(testBitmapData.rect, testVectorInt); shader.data.src.input = testBitmapData; shaderJob = new ShaderJob(shader, testBitmapData); shaderJob.start(true); testVectorInt = testBitmapData.getVector(testBitmapData.rect); trace("TEST1 : ", getTimer() - time); }

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  • 3D zooming technique to maintain the relative position of an object on screen

    - by stark
    Is it possible to zoom to a certain point on screen by modifying the field of view and rotating the view of the camera as to keep that point/object in the same place on screen while zooming ? Changing the camera position is not allowed. I projected the 3D pos of the object on screen and remembered it. Then on each frame I calculate the direction to it in camera space and then I construct a rotation matrix to align this direction to Z axis (in cam space). After this, I calculate the direction from the camera to the object in world space and transform this vector with the matrix I obtained earlier and then use this final vector as the camera's new direction. And it's actually "kinda working", the problem is that it is more/less off than the camera's rotation before starting to zoom depending on the area you are trying to zoom in (larger error on edges/corners). It looks acceptable, but I'm not settling for only this. Any suggestions/resources for doing this technique perfectly? If some of you want to explain the math in detail, be my guest, I can understand these things well.

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  • Rotating wheel with touch adding velocity

    - by Lewis
    I have a wheel control in a game which is setup like so: - (void)ccTouchesMoved:(NSSet *)touches withEvent:(UIEvent *)event { UITouch *touch = [touches anyObject]; CGPoint location = [touch locationInView:[touch view]]; location = [[CCDirector sharedDirector] convertToGL:location]; if (CGRectContainsPoint(wheel.boundingBox, location)) { CGPoint firstLocation = [touch previousLocationInView:[touch view]]; CGPoint location = [touch locationInView:[touch view]]; CGPoint touchingPoint = [[CCDirector sharedDirector] convertToGL:location]; CGPoint firstTouchingPoint = [[CCDirector sharedDirector] convertToGL:firstLocation]; CGPoint firstVector = ccpSub(firstTouchingPoint, wheel.position); CGFloat firstRotateAngle = -ccpToAngle(firstVector); CGFloat previousTouch = CC_RADIANS_TO_DEGREES(firstRotateAngle); CGPoint vector = ccpSub(touchingPoint, wheel.position); CGFloat rotateAngle = -ccpToAngle(vector); CGFloat currentTouch = CC_RADIANS_TO_DEGREES(rotateAngle); wheelRotation += (currentTouch - previousTouch) * 0.6; //limit speed 0.6 } } I update the rotation of a the wheel in the update method by doing: wheel.rotation = wheelRotation; Now once the user lets go of the wheel I want it to rotate back to where it was before but not without taking into account the velocity of the swipe the user has done. This is the bit I really can't get my head around. So if the swipe generates a lot of velocity then the wheel will carry on moving slightly in that direction until the overall force which pulls the wheel back to the starting position kicks in. Any ideas/code snippets?

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  • Is creating a separate pool for each individual image created from a png appropriate?

    - by Panzercrisis
    I'm still possibly a little green about object-pooling, and I want to make sure something like this is a sound design pattern before really embarking upon it. Take the following code (which uses the Starling framework in ActionScript 3): [Embed(source = "/../assets/images/game/misc/red_door.png")] private const RED_DOOR:Class; private const RED_DOOR_TEXTURE:Texture = Texture.fromBitmap(new RED_DOOR()); private const m_vRedDoorPool:Vector.<Image> = new Vector.<Image>(50, true); . . . public function produceRedDoor():Image { // get a Red Door image } public function retireRedDoor(pImage:Image):void { // retire a Red Door Image } Except that there are four colors: red, green, blue, and yellow. So now we have a separate pool for each color, a separate produce function for each color, and a separate retire function for each color. Additionally there are several items in the game that follow this 4-color pattern, so for each of them, we have four pools, four produce functions, and four retire functions. There are more colors involved in the images themselves than just their predominant one, so trying to throw all the doors, for instance, in a single pool, and then changing their color properties around isn't going to work. Also the nonexistence of the static keyword is due to its slowness in AS3. Is this the right way to do things?

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  • Is creating a separate pool for each individual png image in the same class appropriate?

    - by Panzercrisis
    I'm still possibly a little green about object-pooling, and I want to make sure something like this is a sound design pattern before really embarking upon it. Take the following code (which uses the Starling framework in ActionScript 3): [Embed(source = "/../assets/images/game/misc/red_door.png")] private const RED_DOOR:Class; private const RED_DOOR_TEXTURE:Texture = Texture.fromBitmap(new RED_DOOR()); private const m_vRedDoorPool:Vector.<Image> = new Vector.<Image>(50, true); . . . public function produceRedDoor():Image { // get a Red Door image } public function retireRedDoor(pImage:Image):void { // retire a Red Door Image } Except that there are four colors: red, green, blue, and yellow. So now we have a separate pool for each color, a separate produce function for each color, and a separate retire function for each color. Additionally there are several items in the game that follow this 4-color pattern, so for each of them, we have four pools, four produce functions, and four retire functions. There are more colors involved in the images themselves than just their predominant one, so trying to throw all the doors, for instance, in a single pool, and then changing their color properties around isn't going to work. Also the nonexistence of the static keyword is due to its slowness in AS3. Is this the right way to do things?

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  • Interesting 3d zooming technique

    - by stark
    Is it possible to zoom to a certain point on screen by modifying the field of view and rotating the camera as to keep that point/object in the same place on screen while zooming ? Changing the camera position is not allowed.. I projected the 3d pos of the object on screen and remembered it. Then on each frame I calculate the direction to it in camera space and then I construct a rotation matrix to align this direction to Z axis (in cam space). After this, I calculate the direction from the camera to the object in world space and transform this vector with the matrix I obtained earlier and then use this final vector as the camera's new direction. And it's actually "kinda working", the problem is that it is more/less off than the camera's rotation before starting to zoom depending on the area you are trying to zoom in (larger error on edges/corners). It looks acceptable, but I'm not settling for only this. Any suggestions/resources for doing this technique perfectly ? If some of you want to explain the math in detail, be my guests, I can understand these things well. Thanks. Edit: I'll check often for responses, I'm really curious about this :D

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