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  • Algorithm for finding a rectangle constrained to its parent

    - by Milo
    Basically what I want to do is illustrated here: I start with A and B, then B is conformed to A to create C. The idea is, given TLBR rectangles A, B, make C I also need to know if it produces an empty rectangle (B outside of A case). I tried this but it just isn't doing what I want: if(clipRect.getLeft() > rect.getLeft()) L = clipRect.getLeft(); else L = rect.getLeft(); if(clipRect.getRight() < rect.getRight()) R = clipRect.getRight(); else R = rect.getRight(); if(clipRect.getBottom() > rect.getBottom()) B = clipRect.getBottom(); else B = rect.getBottom(); if(clipRect.getTop() < rect.getTop()) T = clipRect.getTop(); else T = rect.getTop(); if(L < R && B < T) { clipRect = AguiRectangle(0,0,0,0); } else { clipRect = AguiRectangle::fromTLBR(T,L,B,R); } Thanks

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  • Calling function using 'new' is less expensive than without it?

    - by Matthew Taylor
    Given this very familiar model of prototypal construction: function Rectangle(w,h) { this.width = w; this.height = h; } Rectangle.prototype.area = function() { return this.width * this.height; }; Can anyone explain why calling "new Rectangle(2,3)" is consistently 10x FASTER than calling "Rectangle(2,3)" without the 'new' keyword? I would have assumed that because new adds more complexity to the execution of a function by getting prototypes involved, it would be slower. Example: var myTime; function startTrack() { myTime = new Date(); } function stopTrack(str) { var diff = new Date().getTime() - myTime.getTime(); println(str + ' time in ms: ' + diff); } function trackFunction(desc, func, times) { var i; if (!times) times = 1; startTrack(); for (i=0; i<times; i++) { func(); } stopTrack('(' + times + ' times) ' + desc); } var TIMES = 1000000; trackFunction('new rect classic', function() { new Rectangle(2,3); }, TIMES); trackFunction('rect classic (without new)', function() { Rectangle(2,3); }, TIMES); Yields (in Chrome): (1000000 times) new rect classic time in ms: 33 (1000000 times) rect classic (without new) time in ms: 368 (1000000 times) new rect classic time in ms: 35 (1000000 times) rect classic (without new) time in ms: 374 (1000000 times) new rect classic time in ms: 31 (1000000 times) rect classic (without new) time in ms: 368

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  • Processing velocity-vectors during collision as neatly as possible

    - by DevEight
    Hello. I'm trying to create a good way to handle all possible collisions between two objects. Typically one will be moving and hitting the other, and should then "bounce" away. What I've done so far (I'm creating a typical game where you have a board and bounce a ball at bricks) is to check if the rectangles intersect and if they do, invert the Y-velocity. This is a really ugly and temporary solution that won't work in the long haul and since this is kind of processing is very common in games I'd really like to find a great way of doing this for future projects aswell. Any links or helpful info is appreciated. Below is what my collision-handling function looks like right now. protected void collision() { #region Boundaries if (bal.position.X + bal.velocity.X >= viewportRect.Width || bal.position.X + bal.velocity.X <= 0) { bal.velocity.X *= -1; } if (bal.position.Y + bal.velocity.Y <= 0) { bal.velocity.Y *= -1; } #endregion bal.rect = new Rectangle((int)bal.position.X+(int)bal.velocity.X-bal.sprite.Width/2, (int)bal.position.Y-bal.sprite.Height/2+(int)bal.velocity.Y, bal.sprite.Width, bal.sprite.Height); player.rect = new Rectangle((int)player.position.X-player.sprite.Width/2, (int)player.position.Y-player.sprite.Height/2, player.sprite.Width, player.sprite.Height); if (bal.rect.Intersects(player.rect)) { bal.position.Y = player.position.Y - player.sprite.Height / 2 - bal.sprite.Height / 2; if (player.position.X != player.prevPos.X) { bal.velocity.X -= (player.prevPos.X - player.position.X) / 2; } bal.velocity.Y *= -1; } foreach (Brick b in brickArray.list) { b.rect.X = Convert.ToInt32(b.position.X-b.sprite.Width/2); b.rect.Y = Convert.ToInt32(b.position.Y-b.sprite.Height/2); if (bal.rect.Intersects(b.rect)) { b.recieveHit(); bal.velocity.Y *= -1; } } brickArray.removeDead(); }

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  • What is jQuery for Document.createElementNS()?

    - by C.W.Holeman II
    What is jQuery for Document.createElementNS()? function emleGraphicToSvg(aGraphicNode) { var lu = function luf(aPrefix){ switch (aPrefix){ case 'xhtml': return 'http://www.w3.org/1999/xhtml'; case 'math': return 'http://www.w3.org/1998/Math/MathML'; case 'svg': return 'http://www.w3.org/2000/svg'; } return ''; }; var svg = document.evaluate("svg:svg", aGraphicNode, lu, XPathResult.FIRST_ORDERED_NODE_TYPE, null). singleNodeValue; $(svg).children().remove(); rect = document.createElementNS(lu('svg'), "rect"); rect.setAttribute("x", "35"); rect.setAttribute("y", "25"); rect.setAttribute("width", "200"); rect.setAttribute("height", "50"); rect.setAttribute("class", "emleGraphicOutline"); svg.appendChild(rect); } The code is a simplified fragment from Emle - Electronic Mathematics Laboratory Equipment JavaScript file emle_lab.js. The Look-Up-Function, luf(), maps a complete reference to a shorten name for the namespace in the XPath string and createElementNS(). The existing svg:svg is located, removed and replaced by a new rectangle.

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  • saved image in the picturebox shows no preview

    - by Nivas
    Hi iam new to C# and have loaded the image in the picture box using menustrip and have displayed some text using picturebox_Paint and label. now i tried to save the image (with image and text) using save event from the menustrip. in the saved location the file shows as no preview avaliable and when i tried to open the file it shows out of memory. can any one say where iam going worng.... my coades private void openToolStripMenuItem_Click(object sender, EventArgs e) { string file = ""; OpenFD.FileName = ""; OpenFD.Title = "open image"; OpenFD.InitialDirectory = "C"; OpenFD.Filter = "JPEG|.jpg|Bmp|.bmp|All Files|..*"; if (OpenFD.ShowDialog() == DialogResult.OK) { file = OpenFD.FileName; pictureBox1.Image = Image.FromFile(file); sz = pictureBox1.Size; a=sz.Width; b= sz.Height; } private void pictureBox1_MouseMove(object sender, MouseEventArgs e) { switch (e.Button) { case MouseButtons.Left: { rect = new Rectangle(rect.Left, rect.Top, e.X - rect.Left, e.Y - rect.Top); this.Invalidate(); y = flag.e; Application.DoEvents(); break; } } } private void pictureBox1_MouseDown(object sender, MouseEventArgs e) { rect = new Rectangle(e.X, e.Y, 0, 0); this.Invalidate(); } private void pictureBox1_Paint(object sender, PaintEventArgs e) { using (Pen pen = new Pen(Color.Red, 2)) e.Graphics.DrawRectangle(pen, rect); //e.Graphics.DrawString(label1.Text, label1.Font, new // SolidBrush(label1.ForeColor), label1.Left - pictureBox1.Left, label1.Top - pictureBox1.Top); if (label1.TextAlign == ContentAlignment.TopLeft) { e.Graphics.DrawString(label1.Text, label1.Font, new SolidBrush(label1.ForeColor), label1.Bounds); } else if (label1.TextAlign == ContentAlignment.TopCenter) { SizeF size = e.Graphics.MeasureString(label1.Text, label1.Font); float left = ((float)this.Width + label1.Left) / 2 - size.Width / 2; RectangleF rect1 = new RectangleF(left, (float)label1.Top, size.Width, label1.Height); e.Graphics.DrawString(label1.Text, label1.Font, new SolidBrush(label1.ForeColor), rect1); } else { SizeF size = e.Graphics.MeasureString(label1.Text, label1.Font); float left = (float)label1.Width - size.Width + label1.Left; RectangleF rect1 = new RectangleF(left, (float)label1.Top, size.Width, label1.Height); e.Graphics.DrawString(label1.Text, label1.Font, new SolidBrush(label1.ForeColor), rect1); } label1.Top = rect.Top; label1.Left = rect.Left; label1.Width = rect.Width; label1.Height = rect.Height; } private void saveToolStripMenuItem_Click(object sender, EventArgs e) { SaveFileDialog SaveFD1 = new SaveFileDialog(); //string Sd_file = ""; SaveFD1.FileName = ""; SaveFD1.InitialDirectory = "C"; SaveFD1.Title = "save file Name"; SaveFD1.Filter= "JPG|.jpg|Bmp|.bmp"; if (SaveFD1.ShowDialog() != DialogResult.Cancel) { System.IO.Stream filename = (System.IO.FileStream)SaveFD1.OpenFile(); if (SaveFD1.Filter == "JPG") pictureBox1.Image.Save(SaveFD1.FileName); //pictureBox1.Image.Save (filename, System.Drawing.Imaging.ImageFormat.Jpeg); else if (SaveFD1.Filter == "Bmp") { //pictureBox1.Image.Save(filename, System.Drawing.Imaging.ImageFormat.Bmp); } filename.Close(); } }

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  • dinamically resizing row height in QTreeWidget/QTreeView during edinitg items

    - by serge
    Hi everyone, I have some problems with sizing row's height in QTreeWidget. I use QStyledItemDelegate with QPlainTextEdit. During editing text in QPlainTextEdit i check for changes with a help of: rect = self.blockBoundingRect(self.firstVisibleBlock()) and if text it's height changes i need row in QTreeWidget also resizing. But i don't know how to inform TreeWidget or a Delegate about changes, i even tried to initialize editor with index, that i could use in a future, but it suddenly changes: class MyEditor(QPlainTextEdit): def __init__(self, index = None, parent=None): super(MyEditor, self).__init__(parent) self.index = index self.connect(self, SIGNAL("textChanged()"), self.setHeight) def setHeight(self): if self.index: rect = self.blockBoundingRect(self.firstVisibleBlock()) self.resize(rect.width(), rect.height()) self.emit(SIGNAL("set_height"), QSize(rect.width(), rect.height()), self.index) How can i bound editor's size changes with TreeWidget? And one more thing, by default all items (cells) in TreeWidget have -1 or some big value as default width. I need whole text in cell to be visible, so how can i limit it only by visible range and expand it in height? Thank you in advance, Serge

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  • objective-c description method

    - by rocity
    Maybe I'm stupid...and this is my first question so forgive me...but when I run this code, I get the following output: (FROG idle:0 animating:0 rect:(null) position:{{1,2}{3,4}} tongue:{5,6}) This is wrong because it seems to be skipping the rect format string and placing everything displaced by one. So idle and animating are what i expect, then rect is skipped, but the result from NSStringFromCGRect(self.rect) is placed into position, then the result for position is pushed to tongue, then tongue is not displayed at all. I'm at a loss. - (NSString *)description{ return [NSString stringWithFormat:@"(FROG idle:%i animating:%i rect:%@ position:%@ tongue:%@)", self.idleTime, self.animating, NSStringFromCGRect(self.rect), NSStringFromCGPoint(self.position), tongue ]; }

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  • Objective-C stringWithFormat misses an argument?

    - by rocity
    When I run this code: - (NSString *)description{ return [NSString stringWithFormat:@"(FROG idle:%i animating:%i rect:%@ position:%@ tongue:%@)", self.idleTime, self.animating, NSStringFromCGRect(self.rect), NSStringFromCGPoint(self.position), tongue ]; } I get the following output: (FROG idle:0 animating:0 rect:(null) position:{{1,2}{3,4}} tongue:{5,6}) This is wrong because it seems to be skipping the rect format string and placing everything displaced by one. So idle and animating are what I expect, then rect is skipped, but the result from NSStringFromCGRect(self.rect) is placed into position, then the result for position is pushed to tongue, then tongue is not displayed at all. I'm at a loss.

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  • Why are my lines getting thicker and thicker?

    - by mystify
    I try to draw some lines with different colors. This code tries to draw two rectangles with 1px thin lines. However, the second rectangle is drawn with 2px width lines, while the first one is drawn with 1px width. - (void)addLineFrom:(CGPoint)p1 to:(CGPoint)p2 context:(CGContextRef)context { // set the current point CGContextMoveToPoint(context, p1.x, p1.y); // add a line from the current point to the wanted point CGContextAddLineToPoint(context, p2.x, p2.y); } - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); CGPoint from, to; // ----- draw outer black frame (left, bottom, right) ----- CGContextBeginPath(context); // set the color CGFloat lineColor[4] = {26.0f * colorFactor, 26.0f * colorFactor, 26.0f * colorFactor, 1.0f}; CGContextSetStrokeColor(context, lineColor); // left from = CGPointZero; to = CGPointMake(0.0f, rect.size.height); [self addLineFrom:from to:to context:context]; // bottom from = to; to = CGPointMake(rect.size.width, rect.size.height); [self addLineFrom:from to:to context:context]; // right from = to; to = CGPointMake(rect.size.width, 0.0f); [self addLineFrom:from to:to context:context]; CGContextStrokePath(context); CGContextClosePath(context); // ----- draw the middle light gray frame (left, bottom, right) ----- CGContextSetLineWidth(context, 1.0f); CGContextBeginPath(context); // set the color CGFloat lineColor2[4] = {94.0f * colorFactor, 94.0f * colorFactor, 95.0f * colorFactor, 1.0f}; CGContextSetStrokeColor(context, lineColor2); // left from = CGPointMake(200.0f, 1.0f); to = CGPointMake(200.0f, rect.size.height - 2.0f); [self addLineFrom:from to:to context:context]; // bottom from = to; to = CGPointMake(rect.size.width - 2.0f, rect.size.height - 2.0f); [self addLineFrom:from to:to context:context]; // right from = to; to = CGPointMake(rect.size.width - 2.0f, 1.0f); [self addLineFrom:from to:to context:context]; // top from = to; to = CGPointMake(1.0f, 1.0f); [self addLineFrom:from to:to context:context]; CGContextStrokePath(context); }

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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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  • 2D OBB collision detection, resolving collisions?

    - by Milo
    I currently use OBBs and I have a vehicle that is a rigid body and some buildings. Here is my update() private void update() { camera.setPosition((vehicle.getPosition().x * camera.getScale()) - ((getWidth() ) / 2.0f), (vehicle.getPosition().y * camera.getScale()) - ((getHeight() ) / 2.0f)); //camera.move(input.getAnalogStick().getStickValueX() * 15.0f, input.getAnalogStick().getStickValueY() * 15.0f); if(input.isPressed(ControlButton.BUTTON_GAS)) { vehicle.setThrottle(1.0f, false); } if(input.isPressed(ControlButton.BUTTON_BRAKE)) { vehicle.setBrakes(1.0f); } vehicle.setSteering(input.getAnalogStick().getStickValueX()); vehicle.update(16.6666f / 1000.0f); ArrayList<Building> buildings = city.getBuildings(); for(Building b : buildings) { if(vehicle.getRect().overlaps(b.getRect())) { vehicle.update(-17.0f / 1000.0f); break; } } } The collision detection works well. What doesn't is how they are dealt with. My goal is simple. If the vehicle hits a building, it should stop, and never go into the building. When I apply negative torque to reverse the car should not feel buggy and move away from the building. I don't want this to look buggy. This is my rigid body class: class RigidBody extends Entity { //linear private Vector2D velocity = new Vector2D(); private Vector2D forces = new Vector2D(); private float mass; //angular private float angularVelocity; private float torque; private float inertia; //graphical private Vector2D halfSize = new Vector2D(); private Bitmap image; public RigidBody() { //set these defaults so we don't get divide by zeros mass = 1.0f; inertia = 1.0f; } //intialize out parameters public void initialize(Vector2D halfSize, float mass, Bitmap bitmap) { //store physical parameters this.halfSize = halfSize; this.mass = mass; image = bitmap; inertia = (1.0f / 20.0f) * (halfSize.x * halfSize.x) * (halfSize.y * halfSize.y) * mass; RectF rect = new RectF(); float scalar = 10.0f; rect.left = (int)-halfSize.x * scalar; rect.top = (int)-halfSize.y * scalar; rect.right = rect.left + (int)(halfSize.x * 2.0f * scalar); rect.bottom = rect.top + (int)(halfSize.y * 2.0f * scalar); setRect(rect); } public void setLocation(Vector2D position, float angle) { getRect().set(position, getWidth(), getHeight(), angle); } public Vector2D getPosition() { return getRect().getCenter(); } @Override public void update(float timeStep) { //integrate physics //linear Vector2D acceleration = Vector2D.scalarDivide(forces, mass); velocity = Vector2D.add(velocity, Vector2D.scalarMultiply(acceleration, timeStep)); Vector2D c = getRect().getCenter(); c = Vector2D.add(getRect().getCenter(), Vector2D.scalarMultiply(velocity , timeStep)); setCenter(c.x, c.y); forces = new Vector2D(0,0); //clear forces //angular float angAcc = torque / inertia; angularVelocity += angAcc * timeStep; setAngle(getAngle() + angularVelocity * timeStep); torque = 0; //clear torque } //take a relative Vector2D and make it a world Vector2D public Vector2D relativeToWorld(Vector2D relative) { Matrix mat = new Matrix(); float[] Vector2Ds = new float[2]; Vector2Ds[0] = relative.x; Vector2Ds[1] = relative.y; mat.postRotate(JMath.radToDeg(getAngle())); mat.mapVectors(Vector2Ds); return new Vector2D(Vector2Ds[0], Vector2Ds[1]); } //take a world Vector2D and make it a relative Vector2D public Vector2D worldToRelative(Vector2D world) { Matrix mat = new Matrix(); float[] Vectors = new float[2]; Vectors[0] = world.x; Vectors[1] = world.y; mat.postRotate(JMath.radToDeg(-getAngle())); mat.mapVectors(Vectors); return new Vector2D(Vectors[0], Vectors[1]); } //velocity of a point on body public Vector2D pointVelocity(Vector2D worldOffset) { Vector2D tangent = new Vector2D(-worldOffset.y, worldOffset.x); return Vector2D.add( Vector2D.scalarMultiply(tangent, angularVelocity) , velocity); } public void applyForce(Vector2D worldForce, Vector2D worldOffset) { //add linear force forces = Vector2D.add(forces ,worldForce); //add associated torque torque += Vector2D.cross(worldOffset, worldForce); } @Override public void draw( GraphicsContext c) { c.drawRotatedScaledBitmap(image, getPosition().x, getPosition().y, getWidth(), getHeight(), getAngle()); } } Essentially, when any rigid body hits a building it should exhibit the same behavior. How is collision solving usually done? Thanks

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  • Opposite Force to Apply to a Collided Rigid Body?

    - by Milo
    I'm working on the physics for my GTA2-like game so I can learn more about game physics. The collision detection and resolution are working great. I'm now just unsure how to compute the force to apply to a body after it collides with a wall. My rigid body looks like this: /our simulation object class RigidBody extends Entity { //linear private Vector2D velocity = new Vector2D(); private Vector2D forces = new Vector2D(); private float mass; private Vector2D v = new Vector2D(); //angular private float angularVelocity; private float torque; private float inertia; //graphical private Vector2D halfSize = new Vector2D(); private Bitmap image; private Matrix mat = new Matrix(); private float[] Vector2Ds = new float[2]; private Vector2D tangent = new Vector2D(); private static Vector2D worldRelVec = new Vector2D(); private static Vector2D relWorldVec = new Vector2D(); private static Vector2D pointVelVec = new Vector2D(); private static Vector2D acceleration = new Vector2D(); public RigidBody() { //set these defaults so we don't get divide by zeros mass = 1.0f; inertia = 1.0f; setLayer(LAYER_OBJECTS); } protected void rectChanged() { if(getWorld() != null) { getWorld().updateDynamic(this); } } //intialize out parameters public void initialize(Vector2D halfSize, float mass, Bitmap bitmap) { //store physical parameters this.halfSize = halfSize; this.mass = mass; image = bitmap; inertia = (1.0f / 20.0f) * (halfSize.x * halfSize.x) * (halfSize.y * halfSize.y) * mass; RectF rect = new RectF(); float scalar = 10.0f; rect.left = (int)-halfSize.x * scalar; rect.top = (int)-halfSize.y * scalar; rect.right = rect.left + (int)(halfSize.x * 2.0f * scalar); rect.bottom = rect.top + (int)(halfSize.y * 2.0f * scalar); setRect(rect); } public void setLocation(Vector2D position, float angle) { getRect().set(position.x,position.y, getWidth(), getHeight(), angle); rectChanged(); } public Vector2D getPosition() { return getRect().getCenter(); } @Override public void update(float timeStep) { doUpdate(timeStep); } public void doUpdate(float timeStep) { //integrate physics //linear acceleration.x = forces.x / mass; acceleration.y = forces.y / mass; velocity.x += (acceleration.x * timeStep); velocity.y += (acceleration.y * timeStep); //velocity = Vector2D.add(velocity, Vector2D.scalarMultiply(acceleration, timeStep)); Vector2D c = getRect().getCenter(); v.x = getRect().getCenter().getX() + (velocity.x * timeStep); v.y = getRect().getCenter().getY() + (velocity.y * timeStep); setCenter(v.x, v.y); forces.x = 0; //clear forces forces.y = 0; //angular float angAcc = torque / inertia; angularVelocity += angAcc * timeStep; setAngle(getAngle() + angularVelocity * timeStep); torque = 0; //clear torque } //take a relative Vector2D and make it a world Vector2D public Vector2D relativeToWorld(Vector2D relative) { mat.reset(); Vector2Ds[0] = relative.x; Vector2Ds[1] = relative.y; mat.postRotate(JMath.radToDeg(getAngle())); mat.mapVectors(Vector2Ds); relWorldVec.x = Vector2Ds[0]; relWorldVec.y = Vector2Ds[1]; return relWorldVec; } //take a world Vector2D and make it a relative Vector2D public Vector2D worldToRelative(Vector2D world) { mat.reset(); Vector2Ds[0] = world.x; Vector2Ds[1] = world.y; mat.postRotate(JMath.radToDeg(-getAngle())); mat.mapVectors(Vector2Ds); worldRelVec.x = Vector2Ds[0]; worldRelVec.y = Vector2Ds[1]; return worldRelVec; } //velocity of a point on body public Vector2D pointVelocity(Vector2D worldOffset) { tangent.x = -worldOffset.y; tangent.y = worldOffset.x; pointVelVec.x = (tangent.x * angularVelocity) + velocity.x; pointVelVec.y = (tangent.y * angularVelocity) + velocity.y; return pointVelVec; } public void applyForce(Vector2D worldForce, Vector2D worldOffset) { //add linear force forces.x += worldForce.x; forces.y += worldForce.y; //add associated torque torque += Vector2D.cross(worldOffset, worldForce); } @Override public void draw( GraphicsContext c) { c.drawRotatedScaledBitmap(image, getPosition().x, getPosition().y, getWidth(), getHeight(), getAngle()); } public Vector2D getVelocity() { return velocity; } public void setVelocity(Vector2D velocity) { this.velocity = velocity; } } The way it is given force is by the applyForce method, this method considers angular torque. I'm just not sure how to come up with the vectors in the case where: RigidBody hits static entity RigidBody hits other RigidBody that may or may not be in motion. Would anyone know a way (without too complex math) that I could figure out the opposite force I need to apply to the car? I know the normal it is colliding with and how deep it collided. My main goal is so that say I hit a building from the side, well the car should not just stay there, it should slowly rotate out of it if I'm more than 45 degrees. Right now when I hit a wall I only change the velocity directly which does not consider angular force. Thanks!

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  • Accelerating 2d object collision with other objects [on hold]

    - by Silent Cave
    Making my very first attempt at game programming with SDL/OpenGL. So I made an object Actor witch can move in all four sides with acceleration. And there are bunch of other rectangles to collide to. the image Movement and collision detection alghorythms work just fine by itself, but when combined to prevent the green rectangle from crossing black rectangles, it gives me a kind of funny resault. Let me show you the code first: from Actor.h class Actor{ public: SDL_Rect * dim; alphaColor * col; float speed; float xlGrav, xrGrav, yuGrav, ydGrav; float acceleration; bool left,right,up,down; Actor(SDL_Rect * dim,alphaColor * col, float speed, float acceleration); bool colides(const SDL_Rect & rect); bool check_for_collisions(const std::vector<SDL_Rect*> & gameObjects ); }; from actor.cpp bool Actor::colides(const SDL_Rect & rect){ if (dim->x + dim->w < rect.x) return false; if (dim->x > rect.x + rect.w) return false; if (dim->y + dim->h < rect.y) return false; if (dim->y > rect.y + rect.h) return false; return true; } movement logic from main.cpp if (actor->left){ if(actor->xlGrav < actor->speed){ actor->xlGrav += actor->speed*actor->acceleration; }else actor->xlGrav = actor->speed; actor->dim->x -= actor->xlGrav; if(actor->check_for_collisions(gameObjects)){ actor->dim->x += actor->xlGrav; actor->xlGrav = 0; } } if (!actor->left){ if(actor->xlGrav - actor->speed*actor->acceleration > 0){ actor->xlGrav -= actor->speed*actor->acceleration; }else actor->xlGrav = 0; actor->dim->x -= actor->xlGrav; if(actor->check_for_collisions(gameObjects)){ actor->dim->x += actor->xlGrav; actor->xlGrav = 0; } } if (actor->right){ if(actor->xrGrav < actor->speed){ actor->xrGrav += actor->speed*actor->acceleration; }else actor->xrGrav = actor->speed; actor->dim->x += actor->xrGrav; if(actor->check_for_collisions(gameObjects)){ actor->dim->x -= actor->xrGrav; actor->xrGrav = 0; } } if (!actor->right){ if(actor->xrGrav - actor->speed*actor->acceleration > 0){ actor->xrGrav -= actor->speed*actor->acceleration; }else actor->xrGrav = 0; actor->dim->x += actor->xrGrav; if(actor->check_for_collisions(gameObjects)){ actor->dim->x -= actor->xrGrav; actor->xrGrav = 0; } } if (actor->up){ if(actor->yuGrav < actor->speed){ actor->yuGrav += actor->speed*actor->acceleration; }else actor->yuGrav = actor->speed; actor->dim->y -= actor->yuGrav; if(actor->check_for_collisions(gameObjects)){ actor->dim->y += actor->yuGrav; actor->yuGrav = 0; } } if (!actor->up){ if(actor->yuGrav - actor->speed*actor->acceleration > 0){ actor->yuGrav -= actor->speed*actor->acceleration; }else actor->yuGrav = 0; actor->dim->y -= actor->yuGrav; if(actor->check_for_collisions(gameObjects)){ actor->dim->y += actor->yuGrav; actor->yuGrav = 0; } } if (actor->down){ if(actor->ydGrav < actor->speed){ actor->ydGrav += actor->speed*actor->acceleration; }else actor->ydGrav = actor->speed; actor->dim->y += actor->ydGrav; if(actor->check_for_collisions(gameObjects)){ actor->dim->y -= actor->ydGrav; actor->ydGrav = 0; } } if (!actor->down){ if(actor->ydGrav - actor->speed*actor->acceleration > 0){ actor->ydGrav -= actor->speed*actor->acceleration; }else actor->ydGrav = 0; actor->dim->y += actor->ydGrav; if(actor->check_for_collisions(gameObjects)){ actor->dim->y -= actor->ydGrav; actor->ydGrav = 0; } } So, if the green box approaches an obstacle from up or left, everything goes as planned - object stops, and it's acceleration drops to zero. But if it comes from bottom or right, it enters into obstacles inner space and starts strangely dance, I'd rather say move in inverted controls. What do I fail to see?

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  • Why does my health bar disappear whenever my character takes amage?

    - by iQue
    Im making health bar for my game that looks like this: public void healthBar(Canvas canvas) { float healthScale = happy.getHP() / happy.getMaxHP(); Rect rect = new Rect(20, 20,(120 * (int)healthScale), 40); Paint paint = new Paint(); paint.setColor(Color.RED); canvas.drawRect(20, 20, 220 * healthScale, 40, paint) } this is called every time my game renders. When the game starts it's where I want it, but as soon as my character (happy) takes any damage, it dissapears. And I know that his hp only gets subtracted by 5 every time he gets hit. So this should not happen? example: @Startup: happy.getHP() == 100, happy.getMaxHP == 100. when damaged HP -=5, -> happy.getHP() == 95 -> healthscale == 0,95 -> 220 * 0,95 == new width for Rect(?)

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  • 2D Tile Collision free movement

    - by andrepcg
    I'm coding a 3D game for a project using OpenGL and I'm trying to do tile collision on a surface. The surface plane is split into a grid of 64x64 pixels and I can simply check if the (x,y) tile is empty or not. Besides having a grid for collision, there's still free movement inside a tile. For each entity, in the end of the update function I simply increase the position by the velocity: pos.x += v.x; pos.y += v.y; I already have a collision grid created but my collide function is not great, i'm not sure how to handle it. I can check if the collision occurs but the way I handle is terrible. int leftTile = repelBox.x / grid->cellSize; int topTile = repelBox.y / grid->cellSize; int rightTile = (repelBox.x + repelBox.w) / grid->cellSize; int bottomTile = (repelBox.y + repelBox.h) / grid->cellSize; for (int y = topTile; y <= bottomTile; ++y) { for (int x = leftTile; x <= rightTile; ++x) { if (grid->getCell(x, y) == BLOCKED){ Rect colBox = grid->getCellRectXY(x, y); Rect xAxis = Rect(pos.x - 20 / 2.0f, pos.y - 20 / 4.0f, 20, 10); Rect yAxis = Rect(pos.x - 20 / 4.0f, pos.y - 20 / 2.0f, 10, 20); if (colBox.Intersects(xAxis)) v.x *= -1; if (colBox.Intersects(yAxis)) v.y *= -1; } } } If instead of reversing the direction I set it to false then when the entity tries to get away from the wall it's still intersecting the tile and gets stuck on that position. EDIT: I've worked with Flashpunk and it has a great function for movement and collision called moveBy. Are there any simplified implementations out there so I can check them out?

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  • Object array updates one instance repeatedly [on hold]

    - by MGN001
    I'm making a 2D shooter, and the player object holds an array of bullets that represent how many shots the player can have on screen at once. At least, this is what I'm trying for. What's happening is that each time any of the objects in the array is called, it seems to update a single object in memory. So, if I fire and then fire again, the object "starts over" from where I shot from and moves twice as fast. I've spent weeks trying to fix this and I've managed nothing. Hopefully another pair of eyes will see something I've missed. Player.cpp #include "Player.h" const int startLives = 3; const int maxHealth = 2; const float speed = 1; const int maxVelocity = 500; const int topBound = WINDOW_HEIGHT / 5 * 3; const int slowRate = 500; const int accRate = 1000; const int maxBullets = 5; const float spriteWidth = 99; const float spriteHeight = 75; const Vector2f startPosition = { (WINDOW_WIDTH / 2) - (spriteWidth / 2), (WINDOW_HEIGHT / 4 * 3) - (spriteHeight / 2) }; Bullet bullets[maxBullets]; Bullet * bulletPointers[maxBullets]; SDL_Texture * playerHealthy; SDL_Texture * playerDamaged; SDL_Texture * currentSprite; SDL_Rect * rect; Vector2f position; Vector2f velocity; int Health; int Lives; Player::Player() { rect = new SDL_Rect(); } Player::~Player() { SDL_DestroyTexture(playerHealthy); SDL_DestroyTexture(playerDamaged); SDL_DestroyTexture(currentSprite); rect = NULL; } void Player::Initialize(SDL_Renderer * renderer) { SDL_Surface * temp; temp = IMG_Load(".\\Sprites\\player.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } playerHealthy = SDL_CreateTextureFromSurface(renderer, temp); temp = IMG_Load(".\\Sprites\\playerDamaged.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } playerDamaged = SDL_CreateTextureFromSurface(renderer, temp); temp = IMG_Load(".\\Sprites\\laserGreen.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } SDL_Texture * bullet = SDL_CreateTextureFromSurface(renderer, temp); temp = IMG_Load(".\\Sprites\\laserGreenShot.png"); if (temp == NULL) { printf("Initialization Error: %s\n", IMG_GetError()); exit(PLAYER_INITIALIZATION_ERROR); } SDL_Texture * explosion = SDL_CreateTextureFromSurface(renderer, temp); for (int i = 0; i < maxBullets; i++) { bullets[i].Initialize(renderer, bullet, explosion); bulletPointers[i] = NULL; } temp = NULL; rect->h = spriteHeight; rect->w = spriteWidth; Reset(); } void Player::Update(Input input, float deltaTime) { if (abs(velocity.x) < slowRate * deltaTime) { velocity.x = 0; } else if (velocity.x > 0) { velocity.x -= slowRate * deltaTime; } else if (velocity.x < 0) { velocity.x += slowRate * deltaTime; } if (abs(velocity.y) < slowRate * deltaTime) { velocity.y = 0; } if (velocity.y > 0) { velocity.y -= slowRate * deltaTime; } else if (velocity.y < 0) { velocity.y += slowRate * deltaTime; } if (Health <= 0) { --Lives; Spawn(); } velocity.x += UnitVector(input.InputNew.movement).x * accRate * deltaTime; velocity.y += UnitVector(input.InputNew.movement).y * accRate * deltaTime; if (Magnitude(velocity) > maxVelocity) { velocity.x = UnitVector(velocity).x * maxVelocity; velocity.y = UnitVector(velocity).y * maxVelocity; } position.x += velocity.x * deltaTime * speed; position.y += velocity.y * deltaTime * speed; if (input.InputNew.JumpLeft && !input.InputOld.JumpLeft) { position.x -= spriteWidth; } if (input.InputNew.JumpRight && !input.InputOld.JumpRight) { position.x += spriteWidth; } Boundaries(); rect->x = position.x; rect->y = position.y; if (input.InputNew.Fire && !input.InputOld.Fire) { Fire(); } for (int i = 0; i < maxBullets; ++i) { if (bulletPointers[i] != NULL) { bullets[i].Update(deltaTime); if (bullets[i].getPosition().y < -33) { bulletPointers[i] = NULL; } } } } void Player::Draw(SDL_Renderer * renderer) { for (int i = 0; i < maxBullets; ++i) { if (bulletPointers[i] != NULL) { bullets[i].Draw(renderer); } } SDL_RenderCopy(renderer, currentSprite, NULL, rect); } void Player::Spawn() { position = startPosition; Health = maxHealth; currentSprite = playerHealthy; rect->x = position.x; rect->y = position.y; } void Player::Boundaries() { if (position.x < 0) { position.x = 0; velocity.x *= -1; } else if (position.x > WINDOW_WIDTH - spriteWidth) { position.x = WINDOW_WIDTH - spriteWidth; velocity.x *= -1; } if (position.y < topBound) { position.y = topBound; velocity.y *= -1; } else if (position.y > WINDOW_HEIGHT - spriteHeight) { position.y = WINDOW_HEIGHT - spriteHeight; velocity.y *= -1; } } int Player::getLives() { return Lives; } void Player::Reset() { Lives = startLives; Spawn(); } void Player::Fire() { for (int i = 0; i < maxBullets; ++i) { if (bulletPointers[i] == NULL) { bulletPointers[i] = &bullets[i]; bullets[i].Fire(position,velocity.x/2); break; } } } Bullet.cpp #include "Bullet.h" const int speed = 500; Vector2f bulletVelocity; float ExplosionMax = 0.5f; float ExplosionTimer; const Vector2f fireOffset = { 45.5f, 10.0f }; const Vector2f explosionOffset = { 23.5f, -27.0f }; const Vector2i bulletSize = { 9, 33 }; const Vector2i explosionSize = { 56, 54 }; Vector2f bulletPosition; SDL_Texture * bulletSprite; SDL_Texture * explosionSprite; SDL_Texture * bulletCurrentSprite; SDL_Rect * bulletRect; Bullet::Bullet() { } Bullet::~Bullet() { } void Bullet::Initialize(SDL_Renderer * renderer, SDL_Texture * bullet, SDL_Texture * explosion) { bulletSprite = bullet; explosionSprite = explosion; bulletRect = new SDL_Rect(); } void Bullet::Update(float deltaTime) { bulletPosition.y -= bulletVelocity.y * deltaTime; bulletPosition.x += bulletVelocity.x * deltaTime; bulletRect->x = static_cast<int>(bulletPosition.x); bulletRect->y = static_cast<int>(bulletPosition.y); } void Bullet::Draw(SDL_Renderer * renderer) { SDL_RenderCopy(renderer, bulletCurrentSprite, NULL, bulletRect); } void Bullet::Fire(Vector2f pos, float xSpeed) { bulletPosition.x = pos.x + fireOffset.x; bulletPosition.y = pos.y + fireOffset.y; bulletVelocity.x = xSpeed; bulletVelocity.y = speed; bulletCurrentSprite = bulletSprite; bulletRect->h = bulletSize.y; bulletRect->w = bulletSize.x; bulletRect->x = static_cast<int>(bulletPosition.x); bulletRect->y = static_cast<int>(bulletPosition.y); } Vector2f Bullet::getPosition() { return bulletPosition; } void Bullet::Hit() { bulletCurrentSprite = explosionSprite; bulletVelocity = { 0.0f, 0.0f }; ExplosionTimer = ExplosionMax; bulletPosition.x += explosionOffset.x; bulletPosition.y += explosionOffset.y; bulletRect->w = explosionSize.x; bulletRect->h = explosionSize.y; }

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  • iPhone development: pointer being freed was not allocated

    - by w4nderlust
    Hello, i got this message from the debugger: Pixture(1257,0xa0610500) malloc: *** error for object 0x21a8000: pointer being freed was not allocated *** set a breakpoint in malloc_error_break to debug so i did a bit of tracing and got: (gdb) shell malloc_history 1257 0x21a8000 ALLOC 0x2196a00-0x21a89ff [size=73728]: thread_a0610500 |start | main | UIApplicationMain | GSEventRun | GSEventRunModal | CFRunLoopRunInMode | CFRunLoopRunSpecific | __CFRunLoopDoObservers | CA::Transaction::observer_callback(__CFRunLoopObserver*, unsigned long, void*) | CA::Transaction::commit() | CA::Context::commit_transaction(CA::Transaction*) | CALayerDisplayIfNeeded | -[CALayer _display] | CABackingStoreUpdate | backing_callback(CGContext*, void*) | -[CALayer drawInContext:] | -[UIView(CALayerDelegate) drawLayer:inContext:] | -[AvatarView drawRect:] | -[AvatarView overlayPNG:] | +[UIImageUtility createMaskOf:] | UIGraphicsGetImageFromCurrentImageContext | CGBitmapContextCreateImage | create_bitmap_data_provider | malloc | malloc_zone_malloc and i really can't understand what i am doing wrong. here's the code of the [UIImageUtility createMaskOf:] function: + (UIImage *)createMaskOf:(UIImage *)source { CGRect rect = CGRectMake(0, 0, source.size.width, source.size.height); UIGraphicsBeginImageContext(CGSizeMake(source.size.width, source.size.height)); CGContextRef context = UIGraphicsGetCurrentContext(); CGContextTranslateCTM(context, 0, source.size.height); CGContextScaleCTM(context, 1.0, -1.0); UIImage *original = [self createGrayCopy:source]; CGContextRef context2 = CGBitmapContextCreate(NULL, source.size.width, source.size.height, 8, 4 * source.size.width, CGColorSpaceCreateDeviceRGB(), kCGImageAlphaNoneSkipLast); CGContextDrawImage(context2, CGRectMake(0, 0, source.size.width, source.size.height), original.CGImage); CGImageRef unmasked = CGBitmapContextCreateImage(context2); const float myMaskingColorsFrameColor[6] = { 1,256,1,256,1,256 }; CGImageRef mask = CGImageCreateWithMaskingColors(unmasked, myMaskingColorsFrameColor); CGContextSetRGBFillColor (context, 256,256,256, 1); CGContextFillRect(context, rect); CGContextDrawImage(context, rect, mask); UIImage *whiteMasked = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return whiteMasked; } the other custom function called before that is the following: - (UIImage *)overlayPNG:(SinglePart *)sp { NSLog([sp description]); // Rect and context setup CGRect rect = CGRectMake(0, 0, sp.image.size.width, sp.image.size.height); NSLog(@"%f x %f", sp.image.size.width, sp.image.size.height); // Create an image of a color filled rectangle UIImage *baseColor = nil; if (sp.hasOwnColor) { baseColor = [UIImageUtility imageWithRect:rect ofColor:sp.color]; } else { SinglePart *facePart = [editingAvatar.face.partList objectAtIndex:0]; baseColor = [UIImageUtility imageWithRect:rect ofColor:facePart.color]; } // Crete the mask of the layer UIImage *mask = [UIImageUtility createMaskOf:sp.image]; mask = [UIImageUtility createGrayCopy:mask]; // Create a new context for merging the overlay and a mask of the layer UIGraphicsBeginImageContext(CGSizeMake(sp.image.size.width, sp.image.size.height)); CGContextRef context2 = UIGraphicsGetCurrentContext(); // Adjust the coordinate system so that the origin // is in the lower left corner of the view and the // y axis points up CGContextTranslateCTM(context2, 0, sp.image.size.height); CGContextScaleCTM(context2, 1.0, -1.0); // Create masked overlay color layer CGImageRef MaskedImage = CGImageCreateWithMask (baseColor.CGImage, mask.CGImage); // Draw the base color layer CGContextDrawImage(context2, rect, MaskedImage); // Get the result of the masking UIImage* overlayMasked = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); UIGraphicsBeginImageContext(CGSizeMake(sp.image.size.width, sp.image.size.height)); CGContextRef context = UIGraphicsGetCurrentContext(); // Adjust the coordinate system so that the origin // is in the lower left corner of the view and the // y axis points up CGContextTranslateCTM(context, 0, sp.image.size.height); CGContextScaleCTM(context, 1.0, -1.0); // Get the result of the blending of the masked overlay and the base image CGContextDrawImage(context, rect, overlayMasked.CGImage); // Set the blend mode for the next drawn image CGContextSetBlendMode(context, kCGBlendModeOverlay); // Component image drawn CGContextDrawImage(context, rect, sp.image.CGImage); UIImage* blendedImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); CGImageRelease(MaskedImage); return blendedImage; }

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  • Transform OpenGL coordinates to lower UIView coordinates

    - by John Qualis
    Hi, I am new to OpenGL over iPhone. I am developing an iPhone app similar to a barcode reader but with an extra OpenGL layer. The bottommost layer is UIImagePickerController, then I use UIView on top and draw a rectangle at certain co-ordinates on the iphone screen. So far everything is OK. Then I am trying to draw an OpenGL 3-D model in that rectangle. I am able to load a 3-D model in the iPhone based on this code here - http://iphonedevelopment.blogspot.com/2008/12/start-of-wavefront-obj-file-loader.html I am not able to transform the co-ordinates of the rectangle into OpenGL co-ordinates. Appreciate any help. Do I need to use a matrix to translate the currentPosition of the 3-D model so it is drawn within myRect? The code is given below.. Appreciate any help/pointers in this regards. John (void)drawView:(GLView*)view { static GLfloat rotation = 0.0; glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glColor4f(0.0, 0.5, 1.0, 1.0); // The coordinates of the rectangle are myRect.x, // myRect.y, myRect.width, myRect.height // Do I need a transform matrix here? //glOrthof(-160.0f, 160.0f, -240.0f, 240.0f, -1.0f, 1.0f); [plane drawSelf]; .... } -(void)setupView:(GLView*)view { const GLfloat zNear = 0.01, zFar = 1000.0, fieldOfView = 45.0; GLfloat size; glEnable(GL_DEPTH_TEST); glMatrixMode(GL_PROJECTION); //glMatrixMode(GL_MODELVIEW); size = zNear * tanf(DEGREES_TO_RADIANS(fieldOfView) / 2.0); CGRect rect = view.bounds; glFrustumf(-size, size, -size / (rect.size.width / rect.size.height), size / (rect.size.width / rect.size.height), zNear, zFar); glViewport(0, 0, rect.size.width, rect.size.height); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glClearColor(0.0f, 0.0f, 0.0f, 0.0f); }

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  • My 3D object (opengl es) is disappearing behind the iPhone camera view

    - by KLC
    I have an augmented reality iPhone app that I am converting from Core Animation to OpenGL ES 1.1. I have added code that has been modified from the Apple OpenGL template. My problem is that my 3D object , when translating along the negative Z-axis (away from the user), appears to disappear into the camera view, until its completely gone. I have experimented with several solutions, but to no avail. What I have determined: Using the 3D icosahedron from Jeff Lamarche's blog here, the object starts it at 0,0,0 and then translates with decreasing z coordinates. By the time the z value reaches -2.0f, the object is gone. It appears as if it is disappearing behind the camera view. This is how I set my frustrum & viewport (unchanged from Apple's code) glMatrixMode(GL_PROJECTION); size = zNear * tanf(DEGREES_TO_RADIANS(fieldOfView) / 2.0); //Grab the size of the screen CGRect rect = self.bounds; glFrustumf(-size, size, -size / (rect.size.width / rect.size.height), size / (rect.size.width / rect.size.height), zNear, zFar); glViewport(0, 0, rect.size.width, rect.size.height); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); What I have tried: The camera view is the main view and several other views are added to it as subviews, including the openGLView. I have commented those views out for test purposes. I have applied CATransforms to move the openGLView in the z direction -500 and +500, and done the same to the camera view. I have also changed the zFar in the above code to 1.0f, and it still disappears at z position of -2.0, which doesn't make sense (shouldn't it disappear at z=1.0?) My experimentation has got me more confused than when I started ( which usually means I am missing a key piece, but I can't figure out what). Thanks for your help.

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  • The best way to implement drawing features like Keynote

    - by Shamseddine
    Hi all, I'm trying to make a little iPad tool's for drawing simple geometrical objects (rect, rounded rect, ellipse, star, ...). My goal is to make something very close to Keynote (drawing feature), i.e. let the user add a rect (for instance), resizing it and moving it. I want too the user can select many objects and move them together. I've thought about at least 3 differents ways to do that : Extends UIView for each object type, a class for Rect, another for Ellipse, ... With custom drawing method. Then add this view as subview of the global view. Extends CALayer for each object type, a class for Rect, another for Ellipse, ... With custom drawing method. Then add this layer as sublayer of the global view layer's. Extends NSObject for each object type, a class for Rect, another for Ellipse, ... With just a drawing method which will get as argument a CGContext and a Rect and draw directly the form in it. Those methods will be called by the drawing method of the global view. I'm aware that the two first ways come with functions to detect touch on each object, to add easily shadows,... but I'm afraid that they are a little too heavy ? That's why I thought about the last way, which it seems to be straight forward. Which way will be the more efficient ??? Or maybe I didn't thought another way ? Any help will be appreciated ;-) Thanks.

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  • NSTableView won't begin dragging rows if the mouseDown happens within the rect of an NSButtonCell.

    - by Joel Day
    I currently have an odd case where I need to be able to reorder rows in an NSTableView, but the only column happens to be an NSButtonCell. I'm trying to see how I can override NSButtonCell's mouse tracking in order to get it to behave in a way so that the NSTableView will begin dragging the row, but am not having much luck. Additional info that might affect the behavior: With this NSTableView, I am not allowing any rows to be selected, but I have forced mouse tracking to always occur for all cells. This is so that the button can still be clicked even though its row can never be selected. Thanks!

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  • Update graph in real time from server

    - by user1869421
    I'm trying to update a graph with received data, so that the height of the bars increase as more data is received from the server via a websocket. But my code doesn't render a graph in the browser and plot the data points. I cannot see anything wrong with the code. I really need some help here please. ws = new WebSocket("ws://localhost:8888/dh"); var useData = [] //var chart; var chart = d3.select("body") .append("svg:svg") .attr("class", "chart") .attr("width", 420) .attr("height", 200); ws.onmessage = function(evt) { var distances = JSON.parse(evt.data); data = distances.miles; console.log(data); if(useData.length <= 10){ useData.push(data) } else { var draw = function(data){ // Set the width relative to max data value var x = d3.scale.linear() .domain([0, d3.max(useData)]) .range([0, 420]); var y = d3.scale.ordinal() .domain(useData) .rangeBands([0, 120]); var rect = chart.selectAll("rect") .data(useData) // enter rect rect.enter().append("svg:rect") .attr("y", y) .attr("width", x) .attr("height", y.rangeBand()); // update rect rect .attr("y", y) .attr("width", x) .attr("height", y.rangeBand()); var text = chart.selectAll("text") .data(useData) // enter text text.enter().append("svg:text") .attr("x", x) .attr("y", function (d) { return y(d) + y.rangeBand() / 2; }) .attr("dx", -3) // padding-right .attr("dy", ".35em") // vertical-align: middle .attr("text-anchor", "end") // text-align: right .text(String); // update text text .data(useData) .attr("x", x) .text(String); } useData.length = 0; } } Thanks

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  • Changing direction of rotation Pygame

    - by czl
    How would you change the direction of a rotating image/rect in Pygame? Applying positive and negative degree values works but it seems to only be able to rotate one direction throughout my window. Is there a way to ensure a change in direction of rotation? Perhaps change up rotation of a spinning image every 5 seconds, or if able to change the direction of the spin when hitting a X or Y axis. I've added some code below. It seems like switching movement directions is easy with rect.move_ip as long as I specify a speed and have location clause, it does what I want. Unfortunately rotation is't like that. Here I'l adding angles to make sure it spins, but no matter what I try, I'm unable to negate the rotation. def rotate_image(self): #rotate image orig_rect = self.image.get_rect() rot_image = pygame.transform.rotate(self.image, self.angle) rot_rect = orig_rect.copy() rot_rect.center = rot_image.get_rect().center rot_image = rot_image.subsurface(rot_rect).copy() return rot_image def render(self): self.screen.fill(self.bg_color) self.rect.move_ip(0,5) #Y axis movement at 5 px per frame self.angle += 5 #add 5 anglewhen the rect has not hit one of the window self.angle %= 360 if self.rect.left < 0 or self.rect.right > self.width: self.speed[0] = -self.speed[0] self.angle = -self.angle #tried to invert the angle self.angle -= 5 #trying to negate the angle rotation self.angle %= 360 self.screen.blit(self.rotate_image(),self.rect) pygame.display.flip() I would really like to know how to invert rotation of a image. You may provide your own examples.

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  • Does strokeRect: of NSBezierPath always draw a transparent rect? (Cocoa OSX)

    - by Michael Minerva
    I am trying to make a custom selection box for an image view I created and I am trying to use strokeRect: from NSBezierPath but it always seems to be transparent. Called the method set to set the color the blackColor and then also tried using olorWithDeviceRed:green:blue:alpha: but no matter what I have tried the rectangle created always seems to be transparent. Is there a better method to use to draw an empty rectangle?

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  • How do I process a jQuery SVG group event in a single handler?

    - by rmflow
    I'm trying to draw a button using jQuery SVG, the button is a filled rect and the text is placed on top of the rect. Rect and text are grouped and I want to control the mouseover/mouseout events. The problem is: mouseover/mouseout events are triggered separately for every element of the group. Is it possible to make a single event handler for entire group? Here is an example: gClear = svg.group(); btClear = svg.rect(gClear, 10, 10, 100, h-20, 5 ,5, attrs); txtClear = svg.text(gClear, 35, 30, "Clear", {fontFamily: "Verdana", fontWeight: "bold", fontSize: "16px"}); $(gClear, svg.root()).bind("mouseover", function() { $(btClear).animate({svgFill: '#adf'}, 100); }).bind("mouseout", function() { $(btClear).animate({svgFill: '#fff'}, 100); }) When I move the mouse inside the rect the events mouseover/mouseout are triggered. Can I make "text" events transparent or can I have a single event handler for the group?

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