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  • How to attach turrets to tiles in a tile based game

    - by Joseph St. Pierre
    I am a flash developer, and I am building a Tower Defense game. The world is being built through tiles, and I have gotten that accomplished easily. I have also gotten level changes and enemy spawning down as well. However, I wish the player to be able to spawn turrets, and have those turrets be on specific tiles, based upon where the player placed it. Here is my code: stop(); colOffset = 50; rowOffset = 50; guns = []; placed = true; dead = 0; spawned = 0; level = 1; interval = 350 / level; amount = level * 20; counter = 0; numCol = 14; numRow = 10; tiles = []; k = 0; create = false; tileName = new Array("road","grass","end", "start"); board = new Array( new Array(1,1,1,1,3,1,1,1,1,1,2,1,1,1), new Array(1,1,1,0,0,1,1,1,1,1,0,1,1,1), new Array(1,1,1,0,1,1,1,1,1,1,0,0,1,1), new Array(1,1,1,0,0,0,1,1,1,1,1,0,1,1), new Array(1,1,1,0,1,0,0,0,1,1,1,0,0,1), new Array(1,1,1,0,1,1,1,0,0,1,1,1,0,1), new Array(1,1,0,0,1,1,1,1,0,1,1,0,0,1), new Array(1,1,0,1,1,1,1,1,0,1,0,0,1,1), new Array(1,1,0,0,0,0,0,0,0,1,0,1,1,1), new Array(1,1,1,1,1,1,1,1,0,0,0,1,1,1) ); buildBoard(); function buildBoard(){ for ( col = 0; col < numCol; col++){ for ( row = 0; row < numRow; row++){ _root.attachMovie("tile", "tile_" + col + "_" + row, _root.getNextHighestDepth()); theTile = eval("tile_" + col + "_" + row); theTile._x = (col * 50); theTile._y = (row * 50); theTile.row = row; theTile.col = col; tileType = board[row][col]; theTile.gotoAndStop(tileName[tileType]); tiles.push(theTile); } } } init(); function init(){ onEnterFrame = function(){ counter += 1; if ( spawned < amount && counter > 50){ min= _root.attachMovie("minion","minion",_root.getNextHighestDepth()); min._x = tile_4_0._x + 25; min._y = tile_4_0._y + 25; min.health = 100; choose = Math.round(Math.random()); if ( choose == 0 ){ min.waypointX = [ tile_4_1._x +25, tile_3_1._x + 25, tile_3_2._x + 25, tile_3_6._x + 25, tile_2_6._x + 25, tile_2_8._x + 25, tile_8_8._x + 25, tile_8_9._x + 25, tile_10_9._x + 25, tile_10_7._x + 25, tile_11_7._x + 25, tile_11_6._x + 25, tile_12_6._x + 25, tile_12_4._x + 25, tile_11_4._x + 25, tile_11_2._x + 25, tile_10_2._x + 25, tile_10_0._x + 25]; min.waypointY = [ tile_4_1._y +25, tile_3_1._y + 25, tile_3_2._y + 25, tile_3_6._y + 25, tile_2_6._y + 25, tile_2_8._y + 25, tile_8_8._y + 25, tile_8_9._y + 25, tile_10_9._y + 25, tile_10_7._y + 25, tile_11_7._y + 25, tile_11_6._y + 25, tile_12_6._y + 25, tile_12_4._y + 25, tile_11_4._y + 25, tile_11_2._y + 25, tile_10_2._y + 25, tile_10_0._y + 25]; } else if ( choose == 1 ){ min.waypointX = [ tile_4_1._x +25, tile_3_1._x + 25, tile_3_2._x + 25, tile_3_3._x + 25, tile_5_3._x + 25, tile_5_4._x + 25, tile_7_4._x + 25, tile_7_5._x + 25, tile_8_5._x + 25, tile_8_8._x + 25, tile_8_9._x + 25, tile_10_9._x + 25, tile_10_7._x + 25, tile_11_7._x + 25, tile_11_6._x + 25, tile_12_6._x + 25, tile_12_4._x + 25, tile_11_4._x + 25, tile_11_2._x + 25, tile_10_2._x + 25, tile_10_0._x + 25 ]; min.waypointY = [ tile_4_1._y +25, tile_3_1._y + 25, tile_3_2._y + 25, tile_3_3._y + 25, tile_5_3._y + 25, tile_5_4._y + 25, tile_7_4._y + 25, tile_7_5._y + 25, tile_8_5._y + 25, tile_8_8._y + 25, tile_8_9._y + 25, tile_10_9._y + 25, tile_10_7._y + 25, tile_11_7._y + 25, tile_11_6._y + 25, tile_12_6._y + 25, tile_12_4._y + 25, tile_11_4._y + 25, tile_11_2._y + 25, tile_10_2._y + 25, tile_10_0._y + 25 ]; } min.i = 0; counter = 0; spawned += 1; min.onEnterFrame = function(){ dx = this.waypointX[this.i] - this._x; dy = this.waypointY[this.i] - this._y; radians = Math.atan2(dy,dx); degrees = radians * 180 / Math.PI; xspeed = Math.cos(radians); yspeed = Math.sin(radians); this._x += xspeed; this._y += yspeed; if( this._x == this.waypointX[this.i] && this._y == this.waypointY[this.i]){ this.i++; } if ( this._x == tile_10_0._x + 25 && this._y == tile_10_0._y + 25){ this.removeMovieClip(); dead += 1; } } } if ( dead >= amount ){ dead = 0; level += 1; amount = level * 20; spawned = 0; } } btnM.onRelease = function(){ create = true; } } game.onEnterFrame = function(){ } It is possible for me however to complete this task, but only once. I am able to make the turret, drag it over to a tile, and have it attach itself to the tile. No problem. The issue is, I cannot do these multiple times. Please Help.

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  • XNA Sprite Rotation Matrix - Moving Origin

    - by Jon
    I am currently grouping sprites together, then applying a rotation transformation on draw: private void UpdateMatrix(ref Vector2 origin, float radians) { Vector3 matrixorigin = new Vector3(origin, 0); _rotationMatrix = Matrix.CreateTranslation(-matrixorigin) * Matrix.CreateRotationZ(radians) * Matrix.CreateTranslation(matrixorigin); } Where the origin is the Centermost point of my group of sprites. I apply this transformation to each sprite in the group. My problem is that when I adjust the point of origin, my entire sprite group will re-position itself on screen. How could I differentiate the point of rotation used in the transformation, from the position of the sprite group? Is there a better way of creating this transformation matrix?

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  • xbox thumbstick used to rotate sprite, basic formula makes it "stick" or feel "sticky" at 90 degree intervals! how do get smooth rotation?

    - by Hugh
    Context: C#, XNA game I am using a very basic formula to calculate what angle my sprite (spaceship for example) should be facing based on the xbox controller thumbstick ie. you use the thumbstick to rotate the ship! in my main update method: shuttleAngle = (float) Math.Atan2(newGamePadState.ThumbSticks.Right.X, newGamePadState.ThumbSticks.Right.Y); in my main draw method: spriteBatch.Draw(shuttle, shuttleCoords, sourceRectangle, Color.White, shuttleAngle, origin, 1.0f, SpriteEffects.None, 1); as you can see its quite simple, i take the current radians from the thumbstick and store it in a float "shuttleAngle" and then use this as the rotation angle (in radians) arguement for drawing the shuttle. For some reason when i rotate the sprint it feels sticky at 0, 90, 180 and 270 degrees angles, it wants to settle at those angles. its not giving me a smooth and natural rotation like i would feel in a game that uses a similar mechanic. PS: my xbox controller is fine!

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  • UIAccelerometer Detecting angle Problem

    - by mactalent
    Hello All, How to detect the iPhone angle? I mean that when iPhone is straight (i.e) HomeButton is in bottom part, so how to detect 90 Degree from UIAccelerometer Method. CGFloat RadiansToDegrees(CGFloat radians) {return radians * 180/M_PI;}; i try RadiansToDegrees(atan2(acceleration.y, acceleration.x)) but it gives -90 degree angle any helpwould be appreciated.

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  • Prevent full table scan for query with multiple where clauses

    - by Dave Jarvis
    A while ago I posted a message about optimizing a query in MySQL. I have since ported the data and query to PostgreSQL, but now PostgreSQL has the same problem. The solution in MySQL was to force the optimizer to not optimize using STRAIGHT_JOIN. PostgreSQL offers no such option. Here is the explain: Here is the query: SELECT avg(d.amount) AS amount, y.year FROM station s, station_district sd, year_ref y, month_ref m, daily d LEFT JOIN city c ON c.id = 10663 WHERE -- Find all the stations within a specific unit radius ... -- 6371.009 * SQRT( POW(RADIANS(c.latitude_decimal - s.latitude_decimal), 2) + (COS(RADIANS(c.latitude_decimal + s.latitude_decimal) / 2) * POW(RADIANS(c.longitude_decimal - s.longitude_decimal), 2)) ) <= 50 AND -- Ignore stations outside the given elevations -- s.elevation BETWEEN 0 AND 2000 AND sd.id = s.station_district_id AND -- Gather all known years for that station ... -- y.station_district_id = sd.id AND -- The data before 1900 is shaky; insufficient after 2009. -- y.year BETWEEN 1980 AND 2000 AND -- Filtered by all known months ... -- m.year_ref_id = y.id AND m.month = 12 AND -- Whittled down by category ... -- m.category_id = '001' AND -- Into the valid daily climate data. -- m.id = d.month_ref_id AND d.daily_flag_id <> 'M' GROUP BY y.year It appears as though PostgreSQL is looking at the DAILY table first, which is simply not the right way to go about this query as there are nearly 300 million rows. How do I force PostgreSQL to start at the CITY table? Thank you!

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  • Eliminate full table scan due to BETWEEN (and GROUP BY)

    - by Dave Jarvis
    Description According to the explain command, there is a range that is causing a query to perform a full table scan (160k rows). How do I keep the range condition and reduce the scanning? I expect the culprit to be: Y.YEAR BETWEEN 1900 AND 2009 AND Code Here is the code that has the range condition (the STATION_DISTRICT is likely superfluous). SELECT COUNT(1) as MEASUREMENTS, AVG(D.AMOUNT) as AMOUNT, Y.YEAR as YEAR, MAKEDATE(Y.YEAR,1) as AMOUNT_DATE FROM CITY C, STATION S, STATION_DISTRICT SD, YEAR_REF Y FORCE INDEX(YEAR_IDX), MONTH_REF M, DAILY D WHERE -- For a specific city ... -- C.ID = 10663 AND -- Find all the stations within a specific unit radius ... -- 6371.009 * SQRT( POW(RADIANS(C.LATITUDE_DECIMAL - S.LATITUDE_DECIMAL), 2) + (COS(RADIANS(C.LATITUDE_DECIMAL + S.LATITUDE_DECIMAL) / 2) * POW(RADIANS(C.LONGITUDE_DECIMAL - S.LONGITUDE_DECIMAL), 2)) ) <= 50 AND -- Get the station district identification for the matching station. -- S.STATION_DISTRICT_ID = SD.ID AND -- Gather all known years for that station ... -- Y.STATION_DISTRICT_ID = SD.ID AND -- The data before 1900 is shaky; insufficient after 2009. -- Y.YEAR BETWEEN 1900 AND 2009 AND -- Filtered by all known months ... -- M.YEAR_REF_ID = Y.ID AND -- Whittled down by category ... -- M.CATEGORY_ID = '003' AND -- Into the valid daily climate data. -- M.ID = D.MONTH_REF_ID AND D.DAILY_FLAG_ID <> 'M' GROUP BY Y.YEAR Update The SQL is performing a full table scan, which results in MySQL performing a "copy to tmp table", as shown here: +----+-------------+-------+--------+-----------------------------------+--------------+---------+-------------------------------+--------+-------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+--------+-----------------------------------+--------------+---------+-------------------------------+--------+-------------+ | 1 | SIMPLE | C | const | PRIMARY | PRIMARY | 4 | const | 1 | | | 1 | SIMPLE | Y | range | YEAR_IDX | YEAR_IDX | 4 | NULL | 160422 | Using where | | 1 | SIMPLE | SD | eq_ref | PRIMARY | PRIMARY | 4 | climate.Y.STATION_DISTRICT_ID | 1 | Using index | | 1 | SIMPLE | S | eq_ref | PRIMARY | PRIMARY | 4 | climate.SD.ID | 1 | Using where | | 1 | SIMPLE | M | ref | PRIMARY,YEAR_REF_IDX,CATEGORY_IDX | YEAR_REF_IDX | 8 | climate.Y.ID | 54 | Using where | | 1 | SIMPLE | D | ref | INDEX | INDEX | 8 | climate.M.ID | 11 | Using where | +----+-------------+-------+--------+-----------------------------------+--------------+---------+-------------------------------+--------+-------------+ Related http://dev.mysql.com/doc/refman/5.0/en/how-to-avoid-table-scan.html http://dev.mysql.com/doc/refman/5.0/en/where-optimizations.html http://stackoverflow.com/questions/557425/optimize-sql-that-uses-between-clause Thank you!

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  • Model won't render in my XNA game

    - by Daniel Lopez
    I am trying to create a simple 3D game but things aren't working out as they should. For instance, the mode will not display. I created a class that does the rendering so I think that is where the problem lies. P.S I am using models from the MSDN website so I know the models are compatible with XNA. Code: class ModelRenderer { private float aspectratio; private Model model; private Vector3 camerapos; private Vector3 modelpos; private Matrix rotationy; float radiansy = 0; public ModelRenderer(Model m, float AspectRatio, Vector3 initial_pos, Vector3 initialcamerapos) { model = m; if (model.Meshes.Count == 0) { throw new Exception("Invalid model because it contains zero meshes!"); } modelpos = initial_pos; camerapos = initialcamerapos; aspectratio = AspectRatio; return; } public Vector3 CameraPosition { set { camerapos = value; } get { return camerapos; } } public Vector3 ModelPosition { set { modelpos = value; } get { return modelpos; } } public void RotateY(float radians) { radiansy += radians; rotationy = Matrix.CreateRotationY(radiansy); } public float AspectRatio { set { aspectratio = value; } get { return aspectratio; } } public void Draw() { Matrix world = Matrix.CreateTranslation(modelpos) * rotationy; Matrix view = Matrix.CreateLookAt(this.CameraPosition, this.ModelPosition, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1.0f, 10000f); model.Draw(world, view, projection); } } If you need more code just make a comment.

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  • Resultant Vector Algorithm for 2D Collisions

    - by John
    I am making a Pong based game where a puck hits a paddle and bounces off. Both the puck and the paddles are Circles. I came up with an algorithm to calculate the resultant vector of the puck once it meets a paddle. The game seems to function correctly but I'm not entirely sure my algorithm is correct. Here are my variables for the algorithm: Given: velocity = the magnitude of the initial velocity of the puck before the collision x = the x coordinate of the puck y = the y coordinate of the puck moveX = the horizontal speed of the puck moveY = the vertical speed of the puck otherX = the x coordinate of the paddle otherY = the y coordinate of the paddle piece.horizontalMomentum = the horizontal speed of the paddle before it hits the puck piece.verticalMomentum = the vertical speed of the paddle before it hits the puck slope = the direction, in radians, of the puck's velocity distX = the horizontal distance between the center of the puck and the center of the paddle distY = the vertical distance between the center of the puck and the center of the paddle Algorithm solves for: impactAngle = the angle, in radians, of the angle of impact. newSpeedX = the speed of the resultant vector in the X direction newSpeedY = the speed of the resultant vector in the Y direction Here is the code for my algorithm: int otherX = piece.x; int otherY = piece.y; double velocity = Math.sqrt((moveX * moveX) + (moveY * moveY)); double slope = Math.atan(moveX / moveY); int distX = x - otherX; int distY = y - otherY; double impactAngle = Math.atan(distX / distY); double newAngle = impactAngle + slope; int newSpeedX = (int)(velocity * Math.sin(newAngle)) + piece.horizontalMomentum; int newSpeedY = (int)(velocity * Math.cos(newAngle)) + piece.verticalMomentum; for those who are not program savvy here is it simplified: velocity = v(moveX² + moveY²) slope = arctan(moveX / moveY) distX = x - otherX distY = y - otherY impactAngle = arctan(distX / distY) newAngle = impactAngle + slope newSpeedX = velocity * sin(newAngle) + piece.horizontalMomentum newSpeedY = velocity * cos(newAngle) + piece.verticalMomentum My Question: Is this algorithm correct? Is there an easier/simpler way to do what I'm trying to do?

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  • How do I adjust the origin of rotation for a group of sprites?

    - by Jon
    I am currently grouping sprites together, then applying a rotation transformation on draw: private void UpdateMatrix(ref Vector2 origin, float radians) { Vector3 matrixorigin = new Vector3(origin, 0); _rotationMatrix = Matrix.CreateTranslation(-matrixorigin) * Matrix.CreateRotationZ(radians) * Matrix.CreateTranslation(matrixorigin); } Where the origin is the Centermost point of my group of sprites. I apply this transformation to each sprite in the group. My problem is that when I adjust the point of origin, my entire sprite group will re-position itself on screen. How could I differentiate the point of rotation used in the transformation, from the position of the sprite group? Is there a better way of creating this transformation matrix? EDIT Here is the relevant part of the Draw() function: Matrix allTransforms = _rotationMatrix * camera.GetTransformation(); spriteBatch.Begin(SpriteSortMode.BackToFront, null, null, null, null, null, allTransforms); for (int i = 0; i < _map.AllParts.Count; i++) { for (int j = 0; j < _map.AllParts[0].Count; j++) { spriteBatch.Draw(_map.AllParts[i][j].Texture, _map.AllParts[i][j].Position, null, Color.White, 0, _map.AllParts[i][j].Origin, 1.0f, SpriteEffects.None, 0f); } } This all works fine, again, the problem is that when a rotation is set and the point of origin is changed, the sprite group's position is offset on screen. I am trying to figure out a way to adjust the point of origin without causing a shift in position. EDIT 2 At this point, I'm looking for workarounds as this is not working. Does anyone know of a better way to rotate a group of sprites in XNA? I need a method that will allow me to modify the point of rotation (origin) without affecting the position of the sprite group on screen.

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  • Adding 2D vector movement with rotation applied

    - by Michael Zehnich
    I am trying to apply a slight sine wave movement to objects that float around the screen to make them a little more interesting. I would like to apply this to the objects so that they oscillate from side to side, not front to back (so the oscillation does not affect their forward velocity). After reading various threads and tutorials, I have come to the conclusion that I need to create and add vectors, but I simply cannot come up with a solution that works. This is where I'm at right now, in the object's update method (updated based on comments): Vector2 oldPosition = new Vector2(spritePos.X, spritePos.Y); //note: newPosition is initially set in the constructor to spritePos.x/y Vector2 direction = newPosition - oldPosition; Vector2 perpendicular = new Vector2(direction.Y, -direction.X); perpendicular.Normalize(); sinePosAng += 0.1f; perpendicular.X += 2.5f * (float)Math.Sin(sinePosAng); spritePos.X += velocity * (float)Math.Cos(radians); spritePos.Y += velocity * (float)Math.Sin(radians); spritePos += perpendicular; newPosition = spritePos;

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  • UIImagePickerController, UIImage, Memory and More!

    - by Itay
    I've noticed that there are many questions about how to handle UIImage objects, especially in conjunction with UIImagePickerController and then displaying it in a view (usually a UIImageView). Here is a collection of common questions and their answers. Feel free to edit and add your own. I obviously learnt all this information from somewhere too. Various forum posts, StackOverflow answers and my own experimenting brought me to all these solutions. Credit goes to those who posted some sample code that I've since used and modified. I don't remember who you all are - but hats off to you! How Do I Select An Image From the User's Images or From the Camera? You use UIImagePickerController. The documentation for the class gives a decent overview of how one would use it, and can be found here. Basically, you create an instance of the class, which is a modal view controller, display it, and set yourself (or some class) to be the delegate. Then you'll get notified when a user selects some form of media (movie or image in 3.0 on the 3GS), and you can do whatever you want. My Delegate Was Called - How Do I Get The Media? The delegate method signature is the following: - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info; You should put a breakpoint in the debugger to see what's in the dictionary, but you use that to extract the media. For example: UIImage* image = [info objectForKey:UIImagePickerControllerOriginalImage]; There are other keys that work as well, all in the documentation. OK, I Got The Image, But It Doesn't Have Any Geolocation Data. What gives? Unfortunately, Apple decided that we're not worthy of this information. When they load the data into the UIImage, they strip it of all the EXIF/Geolocation data. Can I Get To The Original File Representing This Image on the Disk? Nope. For security purposes, you only get the UIImage. How Can I Look At The Underlying Pixels of the UIImage? Since the UIImage is immutable, you can't look at the direct pixels. However, you can make a copy. The code to this looks something like this: UIImage* image = ...; // An image NSData* pixelData = (NSData*) CGDataProviderCopyData(CGImageGetDataProvider(image.CGImage)); unsigned char* pixelBytes = (unsigned char *)[pixelData bytes]; // Take away the red pixel, assuming 32-bit RGBA for(int i = 0; i < [pixelData length]; i += 4) { pixelBytes[i] = 0; // red pixelBytes[i+1] = pixelBytes[i+1]; // green pixelBytes[i+2] = pixelBytes[i+2]; // blue pixelBytes[i+3] = pixelBytes[i+3]; // alpha } However, note that CGDataProviderCopyData provides you with an "immutable" reference to the data - meaning you can't change it (and you may get a BAD_ACCESS error if you do). Look at the next question if you want to see how you can modify the pixels. How Do I Modify The Pixels of the UIImage? The UIImage is immutable, meaning you can't change it. Apple posted a great article on how to get a copy of the pixels and modify them, and rather than copy and paste it here, you should just go read the article. Once you have the bitmap context as they mention in the article, you can do something similar to this to get a new UIImage with the modified pixels: CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; Do remember to release your references though, otherwise you're going to be leaking quite a bit of memory. After I Select 3 Images From The Camera, I Run Out Of Memory. Help! You have to remember that even though on disk these images take up only a few hundred kilobytes at most, that's because they're compressed as a PNG or JPG. When they are loaded into the UIImage, they become uncompressed. A quick over-the-envelope calculation would be: width x height x 4 = bytes in memory That's assuming 32-bit pixels. If you have 16-bit pixels (some JPGs are stored as RGBA-5551), then you'd replace the 4 with a 2. Now, images taken with the camera are 1600 x 1200 pixels, so let's do the math: 1600 x 1200 x 4 = 7,680,000 bytes = ~8 MB 8 MB is a lot, especially when you have a limit of around 24 MB for your application. That's why you run out of memory. OK, I Understand Why I Have No Memory. What Do I Do? There is never any reason to display images at their full resolution. The iPhone has a screen of 480 x 320 pixels, so you're just wasting space. If you find yourself in this situation, ask yourself the following question: Do I need the full resolution image? If the answer is yes, then you should save it to disk for later use. If the answer is no, then read the next part. Once you've decided what to do with the full-resolution image, then you need to create a smaller image to use for displaying. Many times you might even want several sizes for your image: a thumbnail, a full-size one for displaying, and the original full-resolution image. OK, I'm Hooked. How Do I Resize the Image? Unfortunately, there is no defined way how to resize an image. Also, it's important to note that when you resize it, you'll get a new image - you're not modifying the old one. There are a couple of methods to do the resizing. I'll present them both here, and explain the pros and cons of each. Method 1: Using UIKit + (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize; { // Create a graphics image context UIGraphicsBeginImageContext(newSize); // Tell the old image to draw in this new context, with the desired // new size [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)]; // Get the new image from the context UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext(); // End the context UIGraphicsEndImageContext(); // Return the new image. return newImage; } This method is very simple, and works great. It will also deal with the UIImageOrientation for you, meaning that you don't have to care whether the camera was sideways when the picture was taken. However, this method is not thread safe, and since thumbnailing is a relatively expensive operation (approximately ~2.5s on a 3G for a 1600 x 1200 pixel image), this is very much an operation you may want to do in the background, on a separate thread. Method 2: Using CoreGraphics + (UIImage*)imageWithImage:(UIImage*)sourceImage scaledToSize:(CGSize)newSize; { CGFloat targetWidth = targetSize.width; CGFloat targetHeight = targetSize.height; CGImageRef imageRef = [sourceImage CGImage]; CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef); CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef); if (bitmapInfo == kCGImageAlphaNone) { bitmapInfo = kCGImageAlphaNoneSkipLast; } CGContextRef bitmap; if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) { bitmap = CGBitmapContextCreate(NULL, targetWidth, targetHeight, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } else { bitmap = CGBitmapContextCreate(NULL, targetHeight, targetWidth, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } if (sourceImage.imageOrientation == UIImageOrientationLeft) { CGContextRotateCTM (bitmap, radians(90)); CGContextTranslateCTM (bitmap, 0, -targetHeight); } else if (sourceImage.imageOrientation == UIImageOrientationRight) { CGContextRotateCTM (bitmap, radians(-90)); CGContextTranslateCTM (bitmap, -targetWidth, 0); } else if (sourceImage.imageOrientation == UIImageOrientationUp) { // NOTHING } else if (sourceImage.imageOrientation == UIImageOrientationDown) { CGContextTranslateCTM (bitmap, targetWidth, targetHeight); CGContextRotateCTM (bitmap, radians(-180.)); } CGContextDrawImage(bitmap, CGRectMake(0, 0, targetWidth, targetHeight), imageRef); CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; CGContextRelease(bitmap); CGImageRelease(ref); return newImage; } The benefit of this method is that it is thread-safe, plus it takes care of all the small things (using correct color space and bitmap info, dealing with image orientation) that the UIKit version does. How Do I Resize and Maintain Aspect Ratio (like the AspectFill option)? It is very similar to the method above, and it looks like this: + (UIImage*)imageWithImage:(UIImage*)sourceImage scaledToSizeWithSameAspectRatio:(CGSize)targetSize; { CGSize imageSize = sourceImage.size; CGFloat width = imageSize.width; CGFloat height = imageSize.height; CGFloat targetWidth = targetSize.width; CGFloat targetHeight = targetSize.height; CGFloat scaleFactor = 0.0; CGFloat scaledWidth = targetWidth; CGFloat scaledHeight = targetHeight; CGPoint thumbnailPoint = CGPointMake(0.0,0.0); if (CGSizeEqualToSize(imageSize, targetSize) == NO) { CGFloat widthFactor = targetWidth / width; CGFloat heightFactor = targetHeight / height; if (widthFactor > heightFactor) { scaleFactor = widthFactor; // scale to fit height } else { scaleFactor = heightFactor; // scale to fit width } scaledWidth = width * scaleFactor; scaledHeight = height * scaleFactor; // center the image if (widthFactor > heightFactor) { thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5; } else if (widthFactor < heightFactor) { thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5; } } CGImageRef imageRef = [sourceImage CGImage]; CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef); CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef); if (bitmapInfo == kCGImageAlphaNone) { bitmapInfo = kCGImageAlphaNoneSkipLast; } CGContextRef bitmap; if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) { bitmap = CGBitmapContextCreate(NULL, targetWidth, targetHeight, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } else { bitmap = CGBitmapContextCreate(NULL, targetHeight, targetWidth, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } // In the right or left cases, we need to switch scaledWidth and scaledHeight, // and also the thumbnail point if (sourceImage.imageOrientation == UIImageOrientationLeft) { thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x); CGFloat oldScaledWidth = scaledWidth; scaledWidth = scaledHeight; scaledHeight = oldScaledWidth; CGContextRotateCTM (bitmap, radians(90)); CGContextTranslateCTM (bitmap, 0, -targetHeight); } else if (sourceImage.imageOrientation == UIImageOrientationRight) { thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x); CGFloat oldScaledWidth = scaledWidth; scaledWidth = scaledHeight; scaledHeight = oldScaledWidth; CGContextRotateCTM (bitmap, radians(-90)); CGContextTranslateCTM (bitmap, -targetWidth, 0); } else if (sourceImage.imageOrientation == UIImageOrientationUp) { // NOTHING } else if (sourceImage.imageOrientation == UIImageOrientationDown) { CGContextTranslateCTM (bitmap, targetWidth, targetHeight); CGContextRotateCTM (bitmap, radians(-180.)); } CGContextDrawImage(bitmap, CGRectMake(thumbnailPoint.x, thumbnailPoint.y, scaledWidth, scaledHeight), imageRef); CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; CGContextRelease(bitmap); CGImageRelease(ref); return newImage; } The method we employ here is to create a bitmap with the desired size, but draw an image that is actually larger, thus maintaining the aspect ratio. So We've Got Our Scaled Images - How Do I Save Them To Disk? This is pretty simple. Remember that we want to save a compressed version to disk, and not the uncompressed pixels. Apple provides two functions that help us with this (documentation is here): NSData* UIImagePNGRepresentation(UIImage *image); NSData* UIImageJPEGRepresentation (UIImage *image, CGFloat compressionQuality); And if you want to use them, you'd do something like: UIImage* myThumbnail = ...; // Get some image NSData* imageData = UIImagePNGRepresentation(myThumbnail); Now we're ready to save it to disk, which is the final step (say into the documents directory): // Give a name to the file NSString* imageName = @"MyImage.png"; // Now, we have to find the documents directory so we can save it // Note that you might want to save it elsewhere, like the cache directory, // or something similar. NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString* documentsDirectory = [paths objectAtIndex:0]; // Now we get the full path to the file NSString* fullPathToFile = [documentsDirectory stringByAppendingPathComponent:imageName]; // and then we write it out [imageData writeToFile:fullPathToFile atomically:NO]; You would repeat this for every version of the image you have. How Do I Load These Images Back Into Memory? Just look at the various UIImage initialization methods, such as +imageWithContentsOfFile: in the Apple documentation.

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  • XNA 3D model collision is inaccurate

    - by Daniel Lopez
    I am creating a classic game in 3d that deals with asteriods and you have to shoot them and avoid being hit from them. I can generate the asteroids just fine and the ship can shoot bullets just fine. But the asteroids always hit the ship even it doesn't look they are even close. I know 2D collision very well but not 3D so can someone please shed some light to my problem. Thanks in advance. Code For ModelRenderer: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { class ModelRenderer { private float aspectratio; private Model model; private Vector3 camerapos; private Vector3 modelpos; private Matrix rotationy; float radiansy = 0; private bool isalive; public ModelRenderer(Model m, float AspectRatio, Vector3 initial_pos, Vector3 initialcamerapos) { isalive = true; model = m; if (model.Meshes.Count == 0) { throw new Exception("Invalid model because it contains zero meshes!"); } modelpos = initial_pos; camerapos = initialcamerapos; aspectratio = AspectRatio; return; } public float RadiusOfSphere { get { return model.Meshes[0].BoundingSphere.Radius; } } public BoundingBox BoxBounds { get { return BoundingBox.CreateFromSphere(model.Meshes[0].BoundingSphere); } } public BoundingSphere SphereBounds { get { return model.Meshes[0].BoundingSphere; } } public Vector3 CameraPosition { set { camerapos = value; } get { return camerapos; } } public bool IsAlive { get { return isalive; } } public Vector3 ModelPosition { set { modelpos = value; } get { return modelpos; } } public void RotateY(float radians) { radiansy += radians; rotationy = Matrix.CreateRotationY(radiansy); } public Matrix RotationY { set { rotationy = value; } get { return rotationy; } } public float AspectRatio { set { aspectratio = value; } get { return aspectratio; } } public void Kill() { isalive = false; } public void Draw(float scale) { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateScale(scale) * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } public void Draw() { Matrix world; if (rotationy == new Matrix(0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)) { world = Matrix.CreateTranslation(modelpos); } else { world = rotationy * Matrix.CreateTranslation(modelpos); } Matrix view = Matrix.CreateLookAt(camerapos, Vector3.Zero, Vector3.Up); Matrix projection = Matrix.CreatePerspectiveFieldOfView(MathHelper.ToRadians(45.0f), this.AspectRatio, 1f, 100000f); foreach (ModelMesh mesh in model.Meshes) { foreach (BasicEffect effect in mesh.Effects) { effect.World = world; effect.View = view; effect.Projection = projection; } mesh.Draw(); } } } Code For Game1: using System; using System.Collections.Generic; using System.Linq; using Microsoft.Xna.Framework; using Microsoft.Xna.Framework.Audio; using Microsoft.Xna.Framework.Content; using Microsoft.Xna.Framework.GamerServices; using Microsoft.Xna.Framework.Graphics; using Microsoft.Xna.Framework.Input; using Microsoft.Xna.Framework.Media; namespace _3D_Asteroids { /// <summary> /// This is the main type for your game /// </summary> public class Game1 : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; int score = 0, lives = 5; SpriteBatch spriteBatch; GameState gstate = GameState.OnMenuScreen; Menu menu = new Menu(Color.Yellow, Color.White); SpriteFont font; Texture2D background; ModelRenderer ship; Model b, a; List<ModelRenderer> bullets = new List<ModelRenderer>(); List<ModelRenderer> asteriods = new List<ModelRenderer>(); float time = 0.0f; int framecount = 0; SoundEffect effect; public Game1() { graphics = new GraphicsDeviceManager(this); graphics.PreferredBackBufferWidth = 1280; graphics.PreferredBackBufferHeight = 796; graphics.ApplyChanges(); Content.RootDirectory = "Content"; } /// <summary> /// Allows the game to perform any initialization it needs to before starting to run. /// This is where it can query for any required services and load any non-graphic /// related content. Calling base.Initialize will enumerate through any components /// and initialize them as well. /// </summary> protected override void Initialize() { // TODO: Add your initialization logic here base.Initialize(); } /// <summary> /// LoadContent will be called once per game and is the place to load /// all of your content. /// </summary> protected override void LoadContent() { // Create a new SpriteBatch, which can be used to draw textures. spriteBatch = new SpriteBatch(GraphicsDevice); font = Content.Load<SpriteFont>("Fonts\\Lucida Console"); background = Content.Load<Texture2D>("Textures\\B1_stars"); Model p1 = Content.Load<Model>("Models\\p1_wedge"); b = Content.Load<Model>("Models\\pea_proj"); a = Content.Load<Model>("Models\\asteroid1"); effect = Content.Load<SoundEffect>("Audio\\tx0_fire1"); ship = new ModelRenderer(p1, GraphicsDevice.Viewport.AspectRatio, new Vector3(0, 0, 0), new Vector3(0, 0, 9000)); } /// <summary> /// UnloadContent will be called once per game and is the place to unload /// all content. /// </summary> protected override void UnloadContent() { } /// <summary> /// Allows the game to run logic such as updating the world, /// checking for collisions, gathering input, and playing audio. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Update(GameTime gameTime) { KeyboardState state = Keyboard.GetState(PlayerIndex.One); switch (gstate) { case GameState.OnMenuScreen: { if (state.IsKeyDown(Keys.Enter)) { switch (menu.SelectedChoice) { case MenuChoices.Play: { gstate = GameState.GameStarted; break; } case MenuChoices.Exit: { this.Exit(); break; } } } if (state.IsKeyDown(Keys.Down)) { menu.MoveSelectedMenuChoiceDown(gameTime); } else if(state.IsKeyDown(Keys.Up)) { menu.MoveSelectedMenuChoiceUp(gameTime); } else { menu.KeysReleased(); } break; } case GameState.GameStarted: { foreach (ModelRenderer bullet in bullets) { if (bullet.ModelPosition.X < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.Z < (ship.ModelPosition.X + 4000) && bullet.ModelPosition.X > (ship.ModelPosition.Z - 4000) && bullet.ModelPosition.Z > (ship.ModelPosition.Z - 4000)) { bullet.ModelPosition += (bullet.RotationY.Forward * 120); } else if (collidedwithasteriod(bullet)) { bullet.Kill(); } else { bullet.Kill(); } } foreach (ModelRenderer asteroid in asteriods) { if (ship.SphereBounds.Intersects(asteroid.BoxBounds)) { lives -= 1; asteroid.Kill(); // This always hits no matter where the ship goes. } else { asteroid.ModelPosition -= (asteroid.RotationY.Forward * 50); } } for (int index = 0; index < asteriods.Count; index++) { if (asteriods[index].IsAlive == false) { asteriods.RemoveAt(index); } } for (int index = 0; index < bullets.Count; index++) { if (bullets[index].IsAlive == false) { bullets.RemoveAt(index); } } if (state.IsKeyDown(Keys.Left)) { ship.RotateY(0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Right)) { ship.RotateY(-0.1f); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Up)) { ship.ModelPosition += (ship.RotationY.Forward * 50); if (state.IsKeyDown(Keys.Space)) { if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0; } } else if (state.IsKeyDown(Keys.Space)) { time += gameTime.ElapsedGameTime.Milliseconds; if (time < 17) { firebullet(); //effect.Play(); } } else { time = 0.0f; } if ((framecount % 60) == 0) { createasteroid(); framecount = 0; } framecount++; break; } } base.Update(gameTime); } void firebullet() { if (bullets.Count < 3) { ModelRenderer bullet = new ModelRenderer(b, GraphicsDevice.Viewport.AspectRatio, ship.ModelPosition, new Vector3(0, 0, 9000)); bullet.RotationY = ship.RotationY; bullets.Add(bullet); } } void createasteroid() { if (asteriods.Count < 2) { Random random = new Random(); float z = random.Next(-13000, -11000); float x = random.Next(-9000, -8000); Random random2 = new Random(); int degrees = random.Next(0, 45); float radians = MathHelper.ToRadians(degrees); ModelRenderer asteroid = new ModelRenderer(a, GraphicsDevice.Viewport.AspectRatio, new Vector3(x, 0, z), new Vector3(0,0, 9000)); asteroid.RotateY(radians); asteriods.Add(asteroid); } } /// <summary> /// This is called when the game should draw itself. /// </summary> /// <param name="gameTime">Provides a snapshot of timing values.</param> protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.CornflowerBlue); switch (gstate) { case GameState.OnMenuScreen: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); menu.DrawMenu(ref spriteBatch, font, new Vector2(GraphicsDevice.Viewport.Width / 2, GraphicsDevice.Viewport.Height / 2) - new Vector2(50f), 100f); spriteBatch.End(); break; } case GameState.GameStarted: { spriteBatch.Begin(); spriteBatch.Draw(background, Vector2.Zero, Color.White); spriteBatch.DrawString(font, "Score: " + score.ToString() + "\nLives: " + lives.ToString(), Vector2.Zero, Color.White); spriteBatch.End(); ship.Draw(); foreach (ModelRenderer bullet in bullets) { bullet.Draw(); } foreach (ModelRenderer asteroid in asteriods) { asteroid.Draw(0.1f); } break; } } base.Draw(gameTime); } bool collidedwithasteriod(ModelRenderer bullet) { foreach (ModelRenderer asteroid in asteriods) { if (bullet.SphereBounds.Intersects(asteroid.BoxBounds)) { score += 10; asteroid.Kill(); return true; } } return false; } } } }

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  • CGAffineTransform does not rotate subview - MKAnnotationView, CGAffineTransformMakeRotation

    - by ZeroDiv
    I have a view that does 1 simple thing: draws an image. I can rotate the image like this: CGAffineTransform transform = CGAffineTransformMakeRotation((CGFloat)radians); self.transform = transform; // WORKS: DRAWS, ROTATES But if I delegate the image-drawing function to a subview, and apply the rotation transform to the subview: CGAffineTransform transform = CGAffineTransformMakeRotation((CGFloat)radians); self.imageView.transform = transform; // DOESN'T WORK: DRAWS, BUT NO ROTATE I get the image drawn, but no rotation. Why? FWIW the "self" view is an MKAnnotationView.

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  • Optimize date query for large child tables: GiST or GIN?

    - by Dave Jarvis
    Problem 72 child tables, each having a year index and a station index, are defined as follows: CREATE TABLE climate.measurement_12_013 ( -- Inherited from table climate.measurement_12_013: id bigint NOT NULL DEFAULT nextval('climate.measurement_id_seq'::regclass), -- Inherited from table climate.measurement_12_013: station_id integer NOT NULL, -- Inherited from table climate.measurement_12_013: taken date NOT NULL, -- Inherited from table climate.measurement_12_013: amount numeric(8,2) NOT NULL, -- Inherited from table climate.measurement_12_013: category_id smallint NOT NULL, -- Inherited from table climate.measurement_12_013: flag character varying(1) NOT NULL DEFAULT ' '::character varying, CONSTRAINT measurement_12_013_category_id_check CHECK (category_id = 7), CONSTRAINT measurement_12_013_taken_check CHECK (date_part('month'::text, taken)::integer = 12) ) INHERITS (climate.measurement) CREATE INDEX measurement_12_013_s_idx ON climate.measurement_12_013 USING btree (station_id); CREATE INDEX measurement_12_013_y_idx ON climate.measurement_12_013 USING btree (date_part('year'::text, taken)); (Foreign key constraints to be added later.) The following query runs abysmally slow due to a full table scan: SELECT count(1) AS measurements, avg(m.amount) AS amount FROM climate.measurement m WHERE m.station_id IN ( SELECT s.id FROM climate.station s, climate.city c WHERE -- For one city ... -- c.id = 5182 AND -- Where stations are within an elevation range ... -- s.elevation BETWEEN 0 AND 3000 AND 6371.009 * SQRT( POW(RADIANS(c.latitude_decimal - s.latitude_decimal), 2) + (COS(RADIANS(c.latitude_decimal + s.latitude_decimal) / 2) * POW(RADIANS(c.longitude_decimal - s.longitude_decimal), 2)) ) <= 50 ) AND -- -- Begin extracting the data from the database. -- -- The data before 1900 is shaky; insufficient after 2009. -- extract( YEAR FROM m.taken ) BETWEEN 1900 AND 2009 AND -- Whittled down by category ... -- m.category_id = 1 AND m.taken BETWEEN -- Start date. (extract( YEAR FROM m.taken )||'-01-01')::date AND -- End date. Calculated by checking to see if the end date wraps -- into the next year. If it does, then add 1 to the current year. -- (cast(extract( YEAR FROM m.taken ) + greatest( -1 * sign( (extract( YEAR FROM m.taken )||'-12-31')::date - (extract( YEAR FROM m.taken )||'-01-01')::date ), 0 ) AS text)||'-12-31')::date GROUP BY extract( YEAR FROM m.taken ) The sluggishness comes from this part of the query: m.taken BETWEEN /* Start date. */ (extract( YEAR FROM m.taken )||'-01-01')::date AND /* End date. Calculated by checking to see if the end date wraps into the next year. If it does, then add 1 to the current year. */ (cast(extract( YEAR FROM m.taken ) + greatest( -1 * sign( (extract( YEAR FROM m.taken )||'-12-31')::date - (extract( YEAR FROM m.taken )||'-01-01')::date ), 0 ) AS text)||'-12-31')::date The HashAggregate from the plan shows a cost of 10006220141.11, which is, I suspect, on the astronomically huge side. There is a full table scan on the measurement table (itself having neither data nor indexes) being performed. The table aggregates 237 million rows from its child tables. Question What is the proper way to index the dates to avoid full table scans? Options I have considered: GIN GiST Rewrite the WHERE clause Separate year_taken, month_taken, and day_taken columns to the tables What are your thoughts? Thank you!

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  • Rails: Converting from MySQL to PostGres breaks Geokit Distance Calculations???

    - by Kevin
    I recently switched my database from MySQL to PostGres. I also use GeoKit. When I started my app up with the new database already seeded, I get the following error: PGError: ERROR: function radians(character varying) does not exist LINE 1: ...COS(0.661045389762993)*COS(-2.12957994527573)*COS(RADIANS(ti... ^ HINT: No function matches the given name and argument types. You might need to add explicit type casts. Anyone know why this is breaking now? I know GeoKit still works because it's still performing the geocoding in the model per ticket when the database is seeded, it just won't do the distance calculations correctly.

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  • iphone: repeating a transformation

    - by gonso
    Hi I'm trying to represent a view that rotates on the iphone screen. I have a button and when you press it, the view rotates 180 degrees. My problem is that this only works the first time. Here is the code: -(IBAction) flip:(id)sender{ CGAffineTransform transform; //the transform matrix to be used below //BEGIN ANIMATIONS [UIView beginAnimations:nil context:NULL]; [UIView setAnimationDuration:2.0]; //animate if (flag){ transform = CGAffineTransformMakeRotation( RADIANS(180) ); } else { transform = CGAffineTransformMakeRotation( RADIANS(-180) ); } flag = !flag; transform = CGAffineTransformTranslate(transform, 0, 0); self.mySuview.transform = transform; //COMMIT ANIMATIONS [UIView commitAnimations]; } The first time you click, the view spins alright, but when you click again NOTHING happens. No errors, no changes on the view. What am I missing? Thanks Gonso

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  • Rectangle Rotation in Python/Pygame

    - by mramazingguy
    Hey I'm trying to rotate a rectangle around its center and when I try to rotate the rectangle, it moves up and to the left at the same time. Does anyone have any ideas on how to fix this? def rotatePoint(self, angle, point, origin): sinT = sin(radians(angle)) cosT = cos(radians(angle)) return (origin[0] + (cosT * (point[0] - origin[0]) - sinT * (point[1] - origin[1])), origin[1] + (sinT * (point[0] - origin[0]) + cosT * (point[1] - origin[1]))) def rotateRect(self, degrees): center = (self.collideRect.centerx, self.collideRect.centery) self.collideRect.topleft = self.rotatePoint(degrees, self.collideRect.topleft, center) self.collideRect.topright = self.rotatePoint(degrees, self.collideRect.topright, center) self.collideRect.bottomleft = self.rotatePoint(degrees, self.collideRect.bottomleft, center) self.collideRect.bottomright = self.rotatePoint(degrees, self.collideRect.bottomright, center)

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  • Objective-C Moving UIView along a curved path

    - by PruitIgoe
    I'm not sure if I am approaching this the correct way. In my app, when a user touches the screen I capture the point and create an arc from a fixed point to that touch point. I then want to move a UIView along that arc. Here's my code: ViewController.m //method to "shoot" object - KIP_Projectile creates the arc, KIP_Character creates the object I want to move along the arc ... //get arc for trajectory KIP_Projectile* vThisProjectile = [[KIP_Projectile alloc] initWithFrame:CGRectMake(51.0, fatElvisCenterPoint-30.0, touchPoint.x, 60.0)]; vThisProjectile.backgroundColor = [UIColor clearColor]; [self.view addSubview:vThisProjectile]; ... KIP_Character* thisChar = [[KIP_Character alloc] initWithFrame:CGRectMake(51, objCenterPoint-5, imgThisChar.size.width, imgThisChar.size.height)]; thisChar.backgroundColor = [UIColor clearColor]; thisChar.charID = charID; thisChar.charType = 2; thisChar.strCharType = @"Projectile"; thisChar.imgMyImage = imgThisChar; thisChar.myArc = vThisProjectile; [thisChar buildImage]; [thisChar traceArc]; in KIP_Projectile I build the arc using this code: - (CGMutablePathRef) createArcPathFromBottomOfRect : (CGRect) rect : (CGFloat) arcHeight { CGRect arcRect = CGRectMake(rect.origin.x, rect.origin.y + rect.size.height - arcHeight, rect.size.width, arcHeight); CGFloat arcRadius = (arcRect.size.height/2) + (pow(arcRect.size.width, 2) / (8*arcRect.size.height)); CGPoint arcCenter = CGPointMake(arcRect.origin.x + arcRect.size.width/2, arcRect.origin.y + arcRadius); CGFloat angle = acos(arcRect.size.width / (2*arcRadius)); CGFloat startAngle = radians(180) + angle; CGFloat endAngle = radians(360) - angle; CGMutablePathRef path = CGPathCreateMutable(); CGPathAddArc(path, NULL, arcCenter.x, arcCenter.y, arcRadius, startAngle, endAngle, 0); return path; } - (void)drawRect:(CGRect)rect { CGContextRef currentContext = UIGraphicsGetCurrentContext(); _myArcPath = [self createArcPathFromBottomOfRect:self.bounds:30.0]; CGContextSetLineWidth(currentContext, 1); CGFloat red[4] = {1.0f, 0.0f, 0.0f, 1.0f}; CGContextSetStrokeColor(currentContext, red); CGContextAddPath(currentContext, _myArcPath); CGContextStrokePath(currentContext); } Works fine. The arc is displayed with a red stroke on the screen. In KIP_Character, which has been passed it's relevant arc, I am using this code but getting no results. - (void) traceArc { CGMutablePathRef myArc = _myArc.myArcPath; // Set up path movement CAKeyframeAnimation *pathAnimation = [CAKeyframeAnimation animationWithKeyPath:@"position"]; pathAnimation.calculationMode = kCAAnimationPaced; pathAnimation.fillMode = kCAFillModeForwards; pathAnimation.removedOnCompletion = NO; pathAnimation.path = myArc; CGPathRelease(myArc); [self.layer addAnimation:pathAnimation forKey:@"savingAnimation"]; } Any help here would be appreciated.

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  • Stop a rotating object at a specified angle?

    - by Krummelz
    I'm working in JavaScript with HTML5 and the canvas. I have an object which is rotating at a certain speed, and I need the object's rotation to slow down gradually and the front of the object to stop at a specified angle. (I'm using radians, not degrees.) I have a variable to keep track of the angle which the object is facing, as it rotates. How would I go about getting the object to come to rest, facing the direction I want it to?

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  • Error With CBitmapContextCreate, CGContextDrawImage, CGBitmapContextCreateImage

    - by wsidell
    Error: CGBitmapContextCreate: invalid data bytes/row: should be at least 400 for 8 integer bits/component, 3 components, kCGImageAlphaNoneSkipFirst. Error: CGContextDrawImage: invalid context Error: CGBitmapContextCreateImage: invalid context Currently, I have in application that runs perfectly in OS 4.0, but I have been trying to get it to work properly in 3.1.3 and I keep getting the errors mentioned above. I am fairly new to iPhone development and am not exactly sure what the problem would be. I am using image resize code that I found in another post on stackoverflow. Here is the code: - (UIImage*)imageWithImage:(UIImage*)sourceImage scaledToSizeWithSameAspectRatio:(CGSize)targetSize{ CGSize imageSize = sourceImage.size; CGFloat width = imageSize.width; CGFloat height = imageSize.height; CGFloat targetWidth = targetSize.width; CGFloat targetHeight = targetSize.height; CGFloat scaleFactor = 0.0; CGFloat scaledWidth = targetWidth; CGFloat scaledHeight = targetHeight; CGPoint thumbnailPoint = CGPointMake(0.0,0.0); if (CGSizeEqualToSize(imageSize, targetSize) == NO) { CGFloat widthFactor = targetWidth / width; CGFloat heightFactor = targetHeight / height; if (widthFactor > heightFactor) { scaleFactor = widthFactor; // scale to fit height } else { scaleFactor = heightFactor; // scale to fit width } scaledWidth = width * scaleFactor; scaledHeight = height * scaleFactor; // center the image if (widthFactor > heightFactor) { thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5; } else if (widthFactor < heightFactor) { thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5; } } CGImageRef imageRef = [sourceImage CGImage]; CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef); CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef); if (bitmapInfo == kCGImageAlphaNone) { bitmapInfo = kCGImageAlphaNoneSkipLast; } CGContextRef bitmap; if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) { bitmap = CGBitmapContextCreate(NULL, targetWidth, targetHeight, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } else { bitmap = CGBitmapContextCreate(NULL, targetHeight, targetWidth, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } // In the right or left cases, we need to switch scaledWidth and scaledHeight, // and also the thumbnail point if (sourceImage.imageOrientation == UIImageOrientationLeft) { thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x); CGFloat oldScaledWidth = scaledWidth; scaledWidth = scaledHeight; scaledHeight = oldScaledWidth; CGContextRotateCTM (bitmap, radians(90)); CGContextTranslateCTM (bitmap, 0, -targetHeight); } else if (sourceImage.imageOrientation == UIImageOrientationRight) { thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x); CGFloat oldScaledWidth = scaledWidth; scaledWidth = scaledHeight; scaledHeight = oldScaledWidth; CGContextRotateCTM (bitmap, radians(-90)); CGContextTranslateCTM (bitmap, -targetWidth, 0); } else if (sourceImage.imageOrientation == UIImageOrientationUp) { // NOTHING } else if (sourceImage.imageOrientation == UIImageOrientationDown) { CGContextTranslateCTM (bitmap, targetWidth, targetHeight); CGContextRotateCTM (bitmap, radians(-180.)); } CGContextDrawImage(bitmap, CGRectMake(thumbnailPoint.x, thumbnailPoint.y, scaledWidth, scaledHeight), imageRef); CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; CGContextRelease(bitmap); CGImageRelease(ref); return newImage; Any help would be appreciated. If you need more info, I will gladly post it.

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  • Making AI jump on a spot effectively

    - by Pasquale Sada
    How to calculate, in 3D environment, the closest point, from which an AI character can jump onto a platform? Setup I have an initial velocity V(Vx,Vy,VZ) and a spot where the character stands still at S(Sx,Sy,Sz). What I'm trying to achieve is a successful jump on a spot E(Ex,Ey,Ez) where you have clicked on(only lower or higher spot, because I've in place a simple steering behavior for even terrains). There are no obstacles around. I've implemented a formula that can make him jump in a precise way on a spot but you need to declare an angle: the problem arise when the selected spot is straight above your head. It' pretty lame that the char hang there and can reach a thing that is 1cm above is head. I'll share the code I'm using: Vector3 dir = target - transform.position; // get target direction float h = dir.y; // get height difference dir.y = 0; // retain only the horizontal direction float dist = dir.magnitude ; // get horizontal distance float a = angle * Mathf.Deg2Rad; // convert angle to radians dir.y = dist * Mathf.Tan(a); // set dir to the elevation angle dist += h / Mathf.Tan(a); // correct for small height differences // calculate the velocity magnitude float vel = Mathf.Sqrt(dist * Physics.gravity.magnitude / Mathf.Sin(2 *a)); return vel * dir.normalized; Ended up using the lowest angle (20 degree) and checking for collision on the trajectory. If found any increase the angle. Here some code (to improve the code maybe must stop the check at the highest point of the curve): Vector3 BallisticVel(Vector3 target, float angle) { Vector3 dir = target - transform.position; // get target direction float h = dir.y; // get height difference dir.y = 0; // retain only the horizontal direction float dist = dir.magnitude ; // get horizontal distance float a = angle * Mathf.Deg2Rad; // convert angle to radians dir.y = dist * Mathf.Tan(a); // set dir to the elevation angle dist += h / Mathf.Tan(a); // correct for small height differences // calculate the velocity magnitude float vel = Mathf.Sqrt(dist * Physics.gravity.magnitude / Mathf.Sin(2 * a)); return vel * dir.normalized; } Vector3 TrajectoryPoint(Vector3 startingPosition, Vector3 startingVelocity, float n ) { float t = 1/60 ; // seconds per time step Vector3 stepVelocity = t * startingVelocity; // m/s Vector3 stepGravity = t * t * Physics.gravity; // m/s/s return startingPosition + n * stepVelocity + 0.5f * (n*n+n) * stepGravity; } bool CheckTrajectory(Vector3 startingPosition,Vector3 target, float angle_jump) { Debug.Log("checking"); if(angle_jump < 80f) { Debug.Log("if"); Vector3 startingVelocity = BallisticVel(target, angle_jump); for (int i = 0; i < 180; i++) { //Debug.Log(i); Vector3 trajectoryPosition = TrajectoryPoint( startingPosition, startingVelocity, i ); if(Physics.Raycast(trajectoryPosition,Vector3.forward,safeDistance)) { angle_jump += 10; break; // restart loop with the new angle } else continue; } return true; JumpVelocity = BallisticVel(target, angle_jump); } return false; }

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  • Sphinx PHP Geodist problems

    - by James
    Below is my PHP function to call nearby points using Sphinx for MySQL. There are hundreds of thousands of nearby points which to what I can tell, are being indexed by Sphinx, but simply fails silently when searching with Sphinx. Other Sphinx queries I run against other indexes work completely fine. function nearby($latitude, $longitude, $radius) { global $sphinx; $sphinx->SetMatchMode(SPH_MATCH_ALL); $sphinx->SetArrayResult(true); $sphinx->SetLimits(0, 1000); $sphinx->SetGeoAnchor('latitude', 'longitude', (float) deg2rad($latitude), (float) deg2rad($longitude)); $circle = (float) $radius * 1.609344; $sphinx->SetFilterFloatRange('@geodist', 0.0, $circle); $matches = $sphinx->Query('', 'geo'); return $matches; } $nearby = nearby($latitude, $longitude, 10000); var_dump($nearby); This, when called with valid latitude and longitude co-ords and a very large radius for debugging produces: bool(false) Below is my sphinx.conf covering the geo part: source geo { type = mysql sql_host = 127.0.0.1 sql_user = user sql_pass = pass sql_db = db sql_port = 3306 sql_query_pre = set names utf8 sql_query_pre = set session query_cache_type=OFF sql_query = SELECT id,city,region,country,radians(longitude) AS longitude, radians(latitude) AS latitude FROM points; sql_attr_float = longitude sql_attr_float = latitude sql_ranged_throttle = 0 sql_query_info = SELECT * FROM points WHERE id = $id } index geo { source = geo path = /var/data/geo docinfo = extern #mlock = 0 #morphology = none min_word_len = 1 charset_type = utf-8 #charset_table = 0..9, A..Z->a..z, _, a..z, U+410..U+42F->U+430..U+44F, U+430..U+44F ignore_chars = U+00AD html_strip = 0 enable_star = 0 } indexer { mem_limit = 1024M } searchd { port = 3312 log = /var/log/searchd.log query_log = /var/log/query.log read_timeout = 5 max_children = 5 pid_file = /var/log/searchd.pid max_matches = 10000 seamless_rotate = 1 preopen_indexes = 0 unlink_old = 1 }

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  • Extending the .NET type system so the compiler enforces semantic meaning of primitive values in cert

    - by Drew Noakes
    I'm working with geometry a bit at the moment and am converting a lot between degrees and radians. Unfortunately, both of these are represented by double, so there's compile time warning/error if I try to pass a value in degrees where radians are expected. I believe F# has a compile-time solution for this (called units of measure.) I'd like to do something similar in C#. As another example, imagine a SQL library that accepts various query parameters as strings. It'd be good to have a way of enforcing that only clean strings were allowed to be passed in at runtime, and the only way to get a clean string was to pass through some SQL injection attack preventing logic. The obvious solution is to wrap the double/string/whatever in a new type to give it the type information the compiler needs. I'm curious if anyone has an alternative solution. If you do think wrapping is the only/best way, then please go into some of the downsides of the pattern (and any upsides I haven't mentioned too.) I'm especially concerned about the performance of abstracted primitive numeric types on my calculations at runtime.

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  • MD5 implementation notes

    - by vaasu
    While going through RFC1321, I came across the following paragraph: This step uses a 64-element table T[1 ... 64] constructed from the sine function. Let T[i] denote the i-th element of the table, which is equal to the integer part of 4294967296 times abs(sin(i)), where i is in radians. The elements of the table are given in the appendix. From what I understood from paragraph, it means T[i] = Integer_part(4294967296 times abs(sin(i))) We know the following is true for all x: 0 <= sin(x) <= 1 Since i is an integer, abs(sin(i)) may very well be 0 for all values of i. That means table will contain all zero values ( 4294967296 times 0 is 0). In the implementation, this is not true. Why is this so? Appendix contains just the raw values after calculation. It does not show how it is derived from the sine function.

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  • Day 4 - Game Sprites In Action

    - by dapostolov
    Yesterday I drew an image on the screen. Most exciting, but ... I spent more time blogging about it then actual coding. So this next little while I'm going to streamline my game and research and simply post key notes. Quick notes on the last session: The most important thing I wanted to point out were the following methods:           spriteBatch.Begin(SpriteBlendMode.AlphaBlend);           spriteBatch.Draw(sprite, position, Color.White);           spriteBatch.End(); The spriteBatch object is used to draw Textures and a 2D texture is called a Sprite A texture is generally an image, which is called an Asset in XNA The Draw Method in the Game1.cs is looped (until exit) and utilises the spriteBatch object to draw a Scene To begin drawing a Scene you call the Begin Method. To end a Scene you call the End Method. And to place an image on the Scene you call the Draw method. The most simple implementation of the draw method is:           spriteBatch.Draw(sprite, position, Color.White); 1) sprite - the 2D texture you loaded to draw 2) position - the 2d vector, a set of x & y coordinates 3) Color.White - the tint to apply to the texture, in this case, white light = nothing, nada, no tint. Game Sprites In Action! Today, I played around with Draw methods to get comfortable with their "quirks". The following is an example of the above draw method, but with more parameters available for us to use. Let's investigate!             spriteBatch.Draw(sprite, position2, null, Color.White, MathHelper.ToRadians(45.0f), new Vector2(sprite.Width / 2, sprite.Height / 2), 1.0F, SpriteEffects.None, 0.0F); The parameters (in order): 1) sprite  the texture to display 2) position2 the position on the screen / scene this can also be a rectangle 3) null the portion of the image to display within an image null = display full image this is generally used for animation strips / grids (more on this below) 4) Color.White Texture tinting White = no tint 5) MathHelper.ToRadians(45.0f) rotation of the object, in this case 45 degrees rotates from the set plotting point. 6) new Vector(0,0) the plotting point in this case the top left corner the image will rotate from the top left of the texture in the code above, the point is set to the middle of the image. 7) 1.0f Image scaling (1x) 8) SpriteEffects.None you can flip the image horizontally or vertically 9) 0.0f The z index of the image. 0 = closer, 1 behind? And playing around with different combinations I was able to come up with the following whacky display:   Checking off Yesterdays Intention List: learn game development terminology (in progress) - We learned sprite, scene, texture, and asset. how to place and position (rotate) a static image on the screen (completed) - The thing to note was, it's was in radians and I found a cool helper method to convert degrees into radians. Also, the image rotates from it's specified point. how to layer static images on the screen (completed) - I couldn't seem to get the zIndex working, but one things for sure, the order you draw the image in also determines how it is rendered on the screen. understand image scaling (in progress) - I'm not sure I have this fully covered, but for the most part plug a number in the scaling field and the image grows / shrinks accordingly. can we reuse images? (completed) - yes, I loaded one image and plotted the bugger all over the screen. understand how framerate is handled in XNA (in progress) - I hacked together some code to display the framerate each second. A framerate of 60 appears to be the standard. Interesting to note, the GameTime object does provide you with some cool timing capabilities, such as...is the game running slow? Need to investigate this down the road. how to display text , basic shapes, and colors on the screen (in progress) - i got text rendered on the screen, and i understand containing rectangles. However, I didn't display "shapes" & "colors" how to interact with an image (collision of user input?) (todo) how to animate an image and understand basic animation techniques (in progress) - I was able to create a stripe animation of numbers ranging from 1 - 4, each block was 40 x 40 pixles for a total stripe size of 160 x 40. Using the portion (source Rectangle) parameter, i limited this display to each section at varying intervals. It was interesting to note my first implementation animated at rocket speed. I then tried to create a smoother animation by limiting the redraw capacity, which seemed to work. I guess a little more research will have to be put into this for animating characters / scenes. how to detect colliding images or screen edges (todo) - but the rectangle object can detect collisions I believe. how to manipulate the image, lets say colors, stretching (in progress) - I haven't figured out how to modify a specific color to be another color, but the tinting parameter definately could be used. As for stretching, use the rectangle object as the positioning and the image will stretch to fit! how to focus on a segment of an image...like only displaying a frame on a film reel (completed) - as per basic animation techniques what's the best way to manage images (compression, storage, location, prevent artwork theft, etc.) (todo) Tomorrows Intention Tomorrow I am going to take a stab at rendering a game menu and from there I'm going to investigate how I can improve upon the code and techniques. Intention List: Render a menu, fancy or not Show the mouse cursor Hook up click event A basic animation of somesort Investigate image / menu techniques D.

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