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  • Why was my Facebook game rejected with the note that "your app icon must not overlap with content in your cover image?"

    - by peterwilli
    My FB game just recently got rejected for two reasons. The first I fixed, but I just can't see to figure out what they mean by the second, and I was hoping someone else got the same issue and did know what they meant. The remaining error is: Cover Image Your app icon must not overlap with content in your cover image. Click on 'Web Preview' in the 'App Details' section to check for overlap prior to submitting your app. See more here. All I know is that the rejection has something to do with the cover image, not the icons or the screenshots. The web preview of my game looks like this now: Please let me know what to do to get approved.

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  • View overlapping with RelativeLayout on Android 1.5

    - by Justin
    I am having a problem with views overlapping in a RelativeLayout on Android 1.5... Everything is working fine on Android 1.6 and above. I do understand that Android 1.5 has some issues with RelativeLayout, but I was not able to find anything on StackOverflow or the android beginners group for my specific problem. My layout consists of four sections, each of which are made up of a TextView, a Gallery, and another TextView aligned vertically: Running Apps Recent Apps Services Processes When all four sets of these items are displayed everything works fine. However, my app allows the user to specify that some of these are not displayed. If the user turns off Running Apps, Recent Apps, or Services then the remaining sections all of a sudden overlap eachother. Here is my code for the layout. I'm not sure what I am doing wrong. When the user turns off display of a section I use the View.GONE visibility setting: <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:gravity="center_vertical" android:layout_gravity="center_vertical" android:background="@null" > <!-- Running Gallery View Items --> <TextView style="@style/TitleText" android:id="@+id/running_gallery_title_text_id" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="left" android:paddingLeft="1sp" android:paddingRight="10sp" android:text="@string/running_title" /> <Gallery android:id="@+id/running_gallery_id" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_below="@id/running_gallery_title_text_id" android:spacing="5sp" android:clipChildren="false" android:clipToPadding="false" android:unselectedAlpha=".5" /> <TextView style="@style/SubTitleText" android:id="@+id/running_gallery_current_text_id" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_below="@id/running_gallery_id" android:gravity="center_horizontal" /> <!-- Recent Gallery View Items --> <TextView style="@style/TitleText" android:id="@+id/recent_gallery_title_text_id" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/running_gallery_current_text_id" android:gravity="left" android:paddingLeft="1sp" android:paddingRight="10sp" android:text="@string/recent_title" /> <Gallery android:id="@+id/recent_gallery_id" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_below="@id/recent_gallery_title_text_id" android:spacing="5sp" android:clipChildren="false" android:clipToPadding="false" android:unselectedAlpha=".5" /> <TextView style="@style/SubTitleText" android:id="@+id/recent_gallery_current_text_id" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_below="@id/recent_gallery_id" android:gravity="center_horizontal" /> <!-- Service Gallery View Items --> <TextView style="@style/TitleText" android:id="@+id/service_gallery_title_text_id" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_below="@id/recent_gallery_current_text_id" android:gravity="left" android:paddingLeft="1sp" android:paddingRight="10sp" android:text="@string/service_title" /> <Gallery android:id="@+id/service_gallery_id" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_below="@id/service_gallery_title_text_id" android:spacing="5sp" android:clipChildren="false" android:clipToPadding="false" android:unselectedAlpha=".5" /> <TextView style="@style/SubTitleText" android:id="@+id/service_gallery_current_text_id" android:layout_width="fill_parent" android:layout_height="wrap_content" android:layout_below="@id/service_gallery_id" android:gravity="center_horizontal" /> </RelativeLayout> I ommitted the xml for the Processes section in a (somewhat vain) attempt to keep this shorter... What can I do to make this work in Android 1.5? I don't think it is just a matter of reordering the views in the xml because it works fine when everything is displayed.

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  • xcode - iPad App. Status bar overlaps toolBar.

    - by Aakburns
    I have an app fully finished. It is very simple. Uses a toolBar up top with a few buttons. Under this is a WebView. The WebView only opens one URL and there is no way to get away from this site. Thats the point of it. Now the issue. The status bar overlaps the toolBar. My temp solve is to hide the status bar, but I really need it to be there in this app. I'm not sure what the problem is. I'm fairly new to this. Thanks for any help.

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  • Blueprint CSS overlapping divs

    - by Chetan
    I'm using the Blueprint CSS framework, and I want to know how to create overlapping divs. If I try to use an absolutely positioned div inside of a relatively positioned div, it messes up the rest of the styling of the div by Blueprint. What is the correct way to do this?

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  • Automatic Adjusting Range Table

    - by Bradford
    I have a table with a start date range, an end date range, and a few other additional columns. On input of a new record, I want to automatically adjust any overlapping date ranges (shrinking them to allow for the new input). I also want to ensure that no overlapping records can accidentally be inserted into this table. I'm using Oracle and Java for my application code. How should I enforce the prevention of overlapping date ranges and also allow for automatically adjusting overlapping ranges? Should I create an AFTER INSERT trigger, with a dbms_lock to serialize access, to prevent the overlapping data. Then in Java, apply the logic to auto adjust everything? Or should that part be in PL/SQL in stored procedure call? This is something that we need for a couple other tables so it'd be nice to abstract. If anyone has something like this already written, please share :) I did find this reference: http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:474221407101 Here's an example of how each of the 4 overlapping cases should be handled for adjustment on insert: = Example 1 = In DB (Start, End, Value): (0, 10, 'X') **(30, 100, 'Z') (200, 500, 'Y') Input (20, 50, 'A') Gives (0, 10, 'X') **(20, 50, 'A') **(51, 100, 'Z') (200, 500, 'Y') = Example 2 = In DB (Start, End, Value): (0, 10, 'X') **(30, 100, 'Z') (200, 500, 'Y') Input (40, 80, 'A') Gives (0, 10, 'X') **(30, 39, 'Z') **(40, 80, 'A') **(81, 100, 'Z') (200, 500, 'Y') = Example 3 = In DB (Start, End, Value): (0, 10, 'X') **(30, 100, 'Z') (200, 500, 'Y') Input (50, 120, 'A') Gives (0, 10, 'X') **(30, 49, 'Z') **(50, 120, 'A') (200, 500, 'Y') = Example 4 = In DB (Start, End, Value): (0, 10, 'X') **(30, 100, 'Z') (200, 500, 'Y') Input (20, 120, 'A') Gives (0, 10, 'X') **(20, 120, 'A') (200, 500, 'Y') The algorithm is as follows: given range = g; input range = i; output range set = o if i.start <= g.start if i.end >= g.end o_1 = i else o_1 = i o_2 = (o.end + 1, g.end) else if i.end >= g.end o_1 = (g.start, i.start - 1) o_2 = i else o_1 = (g.start, i.start - 1) o_2 = i o_3 = (i.end + 1, i.end)

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  • Random position without overlapping

    - by Hwang
    How to stop MCs from overlapping each other? private function loadWishes():void { for (i; i } } private function checkOverlap(wishB:MovieClip) { wishB.x=Math.random()*stage.stageWidth; wishB.y=Math.random()*stage.stageHeight; for (var i:uint=0; i This doesn't seems to be working cause the amount of it checking whether MC is overlapping is about the amount of MC on stage. how to make it keep checking till everything's fine?

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  • CSS: Making two transparent images overlapping

    - by Pierre
    Hi all, I'm trying to make two transparent images (having the same size/dimension ) overlapping into a div at their top left corner. I tried: <html xmlns="http://www.w3.org/1999/xhtml"> <body> <div style="margin:20px;"> <div id="main" style="overflow:hidden;background-color:red;width:400px;height:400px;border:3px solid blue;"> <img src="myimage1.png" style="position:relative;top:0px;left:0px;z-index:0;"/> <img src="myimage2.png" style="position:relative;top:0px;left:0px;z-index:10;"/> </div> </div> </body> </html> but it doesn't work, the two pictures are concatenated into the parent div. Thanks for your help !

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  • how to prevent divs from overlapping when using no-wrap across table cells

    - by pedalpete
    I'm trying to create an events calendar which has a somewhat 'gantt' chart like bar representing the times of an event, along with the time listed. I've uploaded a page showing the problem As you can see, the problem is that in the 3rd cell, the event div is being overlapped by the previous event div which goes outside the boundary of the cell. The event from the 2nd cell SHOULD expand beyond the cell border, but what I'm trying to get to happen is that WHEN the event from the 2nd cell expands into the 3rd cell, the event on the 3rd cell starts a new line. I believe the problem exists because of the nowrap on the time, but I want the time and in some cases the bar to cross the cell boundary when the time goes from one day to another. All that works now, but I'm having a problem with events overlapping when an event goes from one day to another. I've tried all sorts of :even cells having a different padding, etc. but all these solutions seem to bring up more problems. Is there a way get the no-wrap to force a new long when it crosses into the next cell? or any other solution to this issue?

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  • Overlapping two divs and 'clearing' their parent div

    - by brady8
    My CSS-fu is letting me down here: What I'd like to do is position two child divs to be overlapping: Using position: absolute; top: 0px; left: 0px; is the only way I know how, with the parent set to position: relative. The problem with this is that the child divs are taken out of the layout as per the CSS spec, shrinking the parent div to height: 0px, so that I can't clear that div and put any content below. My amazing ASCII art below details what I'm going for... any ideas? As an aside, I need these divs to be overlapping exactly for jQuery fades, and maybe trying out some of the new Webkit transforms, a la Apple's cardflip demo: http://developer.apple.com/safari/library/samplecode/CardFlip/Introduction/Intro.html If there's another way to get them overlapped exactly in CSS, I'm all ears. Thanks! |-------------------------------------------------| | Parent div | | |-------------------------------------------| | | | | | | | DIVS 1 & 2 (overlapped) | | | | | | | |-------------------------------------------| | |-------------------------------------------------| ...more content below, after clearing the parent...

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  • CSS - Overlapping divs

    - by Jens Törnell
    I have no code to start with. I want to add 2 divs overlapping on each other and then use the new CSS3 Rotate function. The effect I want to create is shown on this page Requirements I don't want to use images I don't mind using CSS3 It should be easy to align the whole thing in the center (which makes it harder to use position: absolute;). It's going to be content below the boxed content (which makes it harder to use position: absolute;). If it's possible without too much position: absolute; it's better. I prefer table free solutions. Have fun!

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  • elements overlapping problem in IE

    - by rayz
    There is a page with drop-down menu "Products" overlapped by next content in IE. It works fine under Gecko or Webkit browsers. http://orbitscripts.com/easily-manage-advertising-across-all-of-your-websites.html z-index property makes no sence. I have no solutions yet. Thanx in advance

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  • In a multidisciplinary team, how much should each member's skills overlap?

    - by spade78
    I've been working in embedded software development for this small startup and our team is pretty small: about 3-4 people. We're responsible for all engineering which involves an RF device controlled by an embedded microcontroller that connects to a PC host which runs some sort of data collection and analysis software. I have come to develop these two guidelines when I work with my colleagues: Define a clear separation of responsibilities and make sure each person's contribution to the final product doesn't overlap. Don't assume your colleagues know everything about their responsibilities. I assume there is some sort of technology that I will need to be competent at to properly interface with the work of my colleagues. The first point is pretty easy for us. I do firmware, one guy does the RF, another does the PC software, and the last does the DSP work. Nothing overlaps in terms of two people's work being mixed into the final product. For that to happen, one guy has to hand off work to another guy who will vet it and integrate it himself. The second point is the heart of my question. I've learned the hard way not to trust the knowledge of my colleagues absolutley no matter how many years experience they claim to have. At least not until they've demonstrated it to me a couple of times. So given that whenever I develop a piece of firmware, if it interfaces with some technology that I don't know then I'll try to learn it and develop a piece of test code that helps me understand what they're doing. That way if my piece of the product comes into conflict with another piece then I have some knowledge about possible causes. For example, the PC guy has started implementing his GUI's in .NET WPF (C#) and using LibUSBdotNET for USB access. So I've been learning C# and the .NET USB library that he uses and I build a little console app to help me understand how that USB library works. Now all this takes extra time and energy but I feel it's justified as it gives me a foothold to confront integration problems. Also I like learning this new stuff so I don't mind. On the other hand I can see how this can turn into a time synch for work that won't make it into the final product and may never turn into a problem. So how much experience/skills overlap do you expect in your teammates relative to your own skills? Does this issue go away as the teams get bigger and more diverse?

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  • In a multidisciplicary team, how much should each member's skills overlap?

    - by spade78
    I've been working in embedded software development for this small startup and our team is pretty small: about 3-4 people. We're responsible for all engineering which involves an RF device controlled by an embedded microcontroller that connects to a PC host which runs some sort of data collection and analysis software. I have come to develop these two guidelines when I work with my colleagues: Define a clear separation of responsibilities and make sure each person's contribution to the final product doesn't overlap. Don't assume your colleagues know everything about their responsibilities. I assume there is some sort of technology that I will need to be competent at to properly interface with the work of my colleagues. The first point is pretty easy for us. I do firmware, one guy does the RF, another does the PC software, and the last does the DSP work. Nothing overlaps in terms of two people's work being mixed into the final product. For that to happen, one guy has to hand off work to another guy who will vet it and integrate it himself. The second point is the heart of my question. I've learned the hard way not to trust the knowledge of my colleagues absolutley no matter how many years experience they claim to have. At least not until they've demonstrated it to me a couple of times. So given that whenever I develop a piece of firmware, if it interfaces with some technology that I don't know then I'll try to learn it and develop a piece of test code that helps me understand what they're doing. That way if my piece of the product comes into conflict with another piece then I have some knowledge about possible causes. For example, the PC guy has started implementing his GUI's in .NET WPF (C#) and using LibUSBdotNET for USB access. So I've been learning C# and the .NET USB library that he uses and I build a little console app to help me understand how that USB library works. Now all this takes extra time and energy but I feel it's justified as it gives me a foothold to confront integration problems. Also I like learning this new stuff so I don't mind. On the other hand I can see how this can turn into a time synch for work that won't make it into the final product and may never turn into a problem. So how much experience/skills overlap do you expect in your teammates relative to your own skills? Does this issue go away as the teams get bigger and more diverse?

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  • What is the best way to check if there is overlap between player and static, non-collidable items in bullet physic engine

    - by tigrou
    I'd like to add non collidable objects (eg: power ups, items, ...) in a game world using Bullet Physics Engine and to know if there is collision between player and them. Some info : there is a lot of items ( 1000), all are box shapes and they don't overlap. Here is things i have tried : btDbvt* bvtItems = new btDbvt(); //btDbvt is a hierachical AABB tree, used by Bullet foreach(var item ...) { btDbvtVolume volume = ... //compute item AABB; bvtItems->insert(volume, (void*)someExtraData); } Then, to find collisions between items and player : playerRigidBody->getAabb(min, max); btDbvtVolume playervolume = ... //compute player AABB bvtItems->collideTV(bvtItems->m_root, playervolume, *someCollisionHandler); This works fairly well (and its very fast), however, there is a problem : it only check items AABB against player AABB. That loss of precision is acceptable for items but not for player which is not a box. It would actually need another check to make sure player really collide with item but i don't know how to do this in Bullet. It would have been nice to have a function like this : playerRigidBody->checkCollisionWithAABB(); After doing trying that, I discovered that a btGhostObject exist and seems to have been made for that. I changed my code like this : foreach(var item...) { btCollisionObject* ghostObject = new btGhostObject(); ghostObject->setCollisionShape(boxShape); ghostObject->setCollisionFlags(ghostObject->getCollisionFlags() | btCollisionObject::CF_NO_CONTACT_RESPONSE); startTransform.setOrigin(...); //item position ghostObject->setWorldTransform(startTransform); dynamicsWorld->addCollisionObject(ghostObject, btBroadphaseProxy::SensorTrigger, btBroadphaseProxy:: CharacterFilter); } It also works ok, but there is a huge fps drop (almost ten times slower) which is not acceptable. Maybe there is something missing (forget set a flag) and Bullet is doing extra job for nothing or maybe all that ghostObjects are polluting broad phase and ghostObject is not the right thing for that. Any help would be appreciated.

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  • AABB vs OBB Collision Resolution jitter on corners

    - by patt4179
    I've implemented a collision library for a character who is an AABB and am resolving collisions between AABB vs AABB and AABB vs OBB. I wanted slopes for certain sections, so I've toyed around with using several OBBs to make one, and it's working great except for one glaring issue; The collision resolution on the corner of an OBB makes the player's AABB jitter up and down constantly. I've tried a few things I've thought of, but I just can't wrap my head around what's going on exactly. Here's a video of what's happening as well as my code: Here's the function to get the collision resolution (I'm likely not doing this the right way, so this may be where the issue lies): public Vector2 GetCollisionResolveAmount(RectangleCollisionObject resolvedObject, OrientedRectangleCollisionObject b) { Vector2 overlap = Vector2.Zero; LineSegment edge = GetOrientedRectangleEdge(b, 0); if (!SeparatingAxisForRectangle(edge, resolvedObject)) { LineSegment rEdgeA = new LineSegment(), rEdgeB = new LineSegment(); Range axisRange = new Range(), rEdgeARange = new Range(), rEdgeBRange = new Range(), rProjection = new Range(); Vector2 n = edge.PointA - edge.PointB; rEdgeA.PointA = RectangleCorner(resolvedObject, 0); rEdgeA.PointB = RectangleCorner(resolvedObject, 1); rEdgeB.PointA = RectangleCorner(resolvedObject, 2); rEdgeB.PointB = RectangleCorner(resolvedObject, 3); rEdgeARange = ProjectLineSegment(rEdgeA, n); rEdgeBRange = ProjectLineSegment(rEdgeB, n); rProjection = GetRangeHull(rEdgeARange, rEdgeBRange); axisRange = ProjectLineSegment(edge, n); float axisMid = (axisRange.Maximum + axisRange.Minimum) / 2; float projectionMid = (rProjection.Maximum + rProjection.Minimum) / 2; if (projectionMid > axisMid) { overlap.X = axisRange.Maximum - rProjection.Minimum; } else { overlap.X = rProjection.Maximum - axisRange.Minimum; overlap.X = -overlap.X; } } edge = GetOrientedRectangleEdge(b, 1); if (!SeparatingAxisForRectangle(edge, resolvedObject)) { LineSegment rEdgeA = new LineSegment(), rEdgeB = new LineSegment(); Range axisRange = new Range(), rEdgeARange = new Range(), rEdgeBRange = new Range(), rProjection = new Range(); Vector2 n = edge.PointA - edge.PointB; rEdgeA.PointA = RectangleCorner(resolvedObject, 0); rEdgeA.PointB = RectangleCorner(resolvedObject, 1); rEdgeB.PointA = RectangleCorner(resolvedObject, 2); rEdgeB.PointB = RectangleCorner(resolvedObject, 3); rEdgeARange = ProjectLineSegment(rEdgeA, n); rEdgeBRange = ProjectLineSegment(rEdgeB, n); rProjection = GetRangeHull(rEdgeARange, rEdgeBRange); axisRange = ProjectLineSegment(edge, n); float axisMid = (axisRange.Maximum + axisRange.Minimum) / 2; float projectionMid = (rProjection.Maximum + rProjection.Minimum) / 2; if (projectionMid > axisMid) { overlap.Y = axisRange.Maximum - rProjection.Minimum; overlap.Y = -overlap.Y; } else { overlap.Y = rProjection.Maximum - axisRange.Minimum; } } return overlap; } And here is what I'm doing to resolve it right now: if (collisionDetection.OrientedRectangleAndRectangleCollide(obb, player.PlayerCollision)) { var resolveAmount = collisionDetection.GetCollisionResolveAmount(player.PlayerCollision, obb); if (Math.Abs(resolveAmount.Y) < Math.Abs(resolveAmount.X)) { var roundedAmount = (float)Math.Floor(resolveAmount.Y); player.PlayerCollision._position.Y -= roundedAmount; } else if (Math.Abs(resolveAmount.Y) <= 30.0f) //Catch cases where the player should be able to step over the top of something { var roundedAmount = (float)Math.Floor(resolveAmount.Y); player.PlayerCollision._position.Y -= roundedAmount; } else { var roundedAmount = (float)Math.Floor(resolveAmount.X); player.PlayerCollision._position.X -= roundedAmount; } } Can anyone see what might be the issue here, or has anyone experienced this before that knows a possible solution? I've tried for a few days to figure this out on my own, but I'm just stumped.

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  • IME window overlap cursor in Edittext, how to prevent it?

    - by backspace7
    I'm using Edittext and it has images and texts. Then, I add image file on Edittext and I click Edittext, IME window shows, naturally. ( * At that time cursor is located at right-bottom corner of added image file.) The problem is IME window overlap cursor, so users complain that 'where is my cursor?' How to prevent that IME window overlap cursor?

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  • Retrieve the coordinates of the *occluding* (closest/drawn) pixels during 3D overlap, using OpenGL?

    - by Big Rich
    Hi, Sorry if the question is not worded well, I'm a new to both 3D and OpenGL. How could I go about obtaining the 3D coordinates of the occluding object, at the point where occlusion is happening (i.e. the 'intersection' of the object in front/closest to the screen)? Just to offer a [very] rudimentary, visual, example, if you were to form an index-finger cross, with your right hand closest to your face, I'd like to know the coordinates of the part of your right finger which obscures the other finger (obviously back within the OpenGL context - no jokers ;-) ). If there is a way to find out both about the occluder (hider) and the occluded (hidden) objects in OpenGL, then that would be of great use, also. Cheers Rich

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  • Matplotlib subplots_adjust hspace so titles and xlabels don't overlap ?

    - by Denis
    With say 3 rows of subplots in matplotlib, xlabels of one row can overlap the title of the next; one has to fiddle with pl.subplots_adjust( hspace ), annoying. Is there a recipe for hspace that prevents overlaps and works for any nrow ? """ matplotlib xlabels overlap titles ? """ import sys import numpy as np import pylab as pl nrow = 3 hspace = .4 # of plot height, titles and xlabels both fall within this ?? exec "\n".join( sys.argv[1:] ) # nrow= ... y = np.arange(10) pl.subplots_adjust( hspace=hspace ) for jrow in range( 1, nrow+1 ): pl.subplot( nrow, 1, jrow ) pl.plot( y**jrow ) pl.title( 5 * ("title %d " % jrow) ) pl.xlabel( 5 * ("xlabel %d " % jrow) ) pl.show() My versions: matplotlib 0.99.1.1, python 2.6.4, Mac osx 10.4.11, backend: Qt4Agg (TkAgg = Exception in Tkinter callback) (For many extra points, can anyone outline how matplotlib's packer / spacer works, along the lines of chapter 17 "the packer" in the Tcl/Tk book ?)

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  • How to check dates don't overlap in a table using TSQL.

    - by Jon
    I have a table with start and finish datetimes that I need to determine if any overlap and not quite sure the best way to go. Initially I was thinking of using a nested cursor as shown below which does work, however I'm checking the same records against each other twice and I'm sure it is not very efficient. eg: this table would result in an overlap. id start end ------------------------------------------------------- 1 2009-10-22 10:19:00.000 2009-10-22 11:40:00.000 2 2009-10-22 10:31:00.000 2009-10-22 13:34:00.000 3 2009-10-22 16:31:00.000 2009-10-22 17:34:00.000 Declare @Start datetime, @End datetime, @OtherStart datetime, @OtherEnd datetime, @id int, @endCheck bit Set @endCheck = 0 DECLARE Cur1 CURSOR FOR select id, start, end from table1 OPEN Cur1 FETCH NEXT FROM Cur1 INTO @id, @Start, @End WHILE @@FETCH_STATUS = 0 AND @endCheck = 0 BEGIN -- Get a cursor on all the other records DECLARE Cur2 CURSOR FOR select start, end from table1 and id != @id OPEN Cur2 FETCH NEXT FROM Cur2 INTO @OtherStart, @OtherEnd WHILE @@FETCH_STATUS = 0 AND @endCheck = 0 BEGIN if ( @Start > @OtherStart AND @Start < @OtherEnd OR @End > @OtherStart AND @End < @OtherEnd ) or ( @OtherStart > @Start AND @OtherStart < @End OR @OtherEnd > @Start AND @OtherEnd < @End ) BEGIN SET @endCheck = 1 END FETCH NEXT FROM Cur2 INTO @OtherStart, @OtherEnd END CLOSE Cur2 DEALLOCATE Cur2 FETCH NEXT FROM Cur1 INTO @id, @Start, @End END CLOSE Cur1 DEALLOCATE Cur1

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  • Ball bouncing at a certain angle and efficiency computations

    - by X Y
    I would like to make a pong game with a small twist (for now). Every time the ball bounces off one of the paddles i want it to be under a certain angle (between a min and a max). I simply can't wrap my head around how to actually do it (i have some thoughts and such but i simply cannot implement them properly - i feel i'm overcomplicating things). Here's an image with a small explanation . One other problem would be that the conditions for bouncing have to be different for every edge. For example, in the picture, on the two small horizontal edges i do not want a perfectly vertical bounce when in the middle of the edge but rather a constant angle (pi/4 maybe) in either direction depending on the collision point (before the middle of the edge, or after). All of my collisions are done with the Separating Axes Theorem (and seem to work fine). I'm looking for something efficient because i want to add a lot of things later on (maybe polygons with many edges and such). So i need to keep to a minimum the amount of checking done every frame. The collision algorithm begins testing whenever the bounding boxes of the paddle and the ball intersect. Is there something better to test for possible collisions every frame? (more efficient in the long run,with many more objects etc, not necessarily easy to code). I'm going to post the code for my game: Paddle Class public class Paddle : Microsoft.Xna.Framework.DrawableGameComponent { #region Private Members private SpriteBatch spriteBatch; private ContentManager contentManager; private bool keybEnabled; private bool isLeftPaddle; private Texture2D paddleSprite; private Vector2 paddlePosition; private float paddleSpeedY; private Vector2 paddleScale = new Vector2(1f, 1f); private const float DEFAULT_Y_SPEED = 150; private Vector2[] Normals2Edges; private Vector2[] Vertices = new Vector2[4]; private List<Vector2> lst = new List<Vector2>(); private Vector2 Edge; #endregion #region Properties public float Speed { get {return paddleSpeedY; } set { paddleSpeedY = value; } } public Vector2[] Normal2EdgesVector { get { NormalsToEdges(this.isLeftPaddle); return Normals2Edges; } } public Vector2[] VertexVector { get { return Vertices; } } public Vector2 Scale { get { return paddleScale; } set { paddleScale = value; NormalsToEdges(this.isLeftPaddle); } } public float X { get { return paddlePosition.X; } set { paddlePosition.X = value; } } public float Y { get { return paddlePosition.Y; } set { paddlePosition.Y = value; } } public float Width { get { return (Scale.X == 1f ? (float)paddleSprite.Width : paddleSprite.Width * Scale.X); } } public float Height { get { return ( Scale.Y==1f ? (float)paddleSprite.Height : paddleSprite.Height*Scale.Y ); } } public Texture2D GetSprite { get { return paddleSprite; } } public Rectangle Boundary { get { return new Rectangle((int)paddlePosition.X, (int)paddlePosition.Y, (int)this.Width, (int)this.Height); } } public bool KeyboardEnabled { get { return keybEnabled; } } #endregion private void NormalsToEdges(bool isLeftPaddle) { Normals2Edges = null; Edge = Vector2.Zero; lst.Clear(); for (int i = 0; i < Vertices.Length; i++) { Edge = Vertices[i + 1 == Vertices.Length ? 0 : i + 1] - Vertices[i]; if (Edge != Vector2.Zero) { Edge.Normalize(); //outer normal to edge !! (origin in top-left) lst.Add(new Vector2(Edge.Y, -Edge.X)); } } Normals2Edges = lst.ToArray(); } public float[] ProjectPaddle(Vector2 axis) { if (Vertices.Length == 0 || axis == Vector2.Zero) return (new float[2] { 0, 0 }); float min, max; min = Vector2.Dot(axis, Vertices[0]); max = min; for (int i = 1; i < Vertices.Length; i++) { float p = Vector2.Dot(axis, Vertices[i]); if (p < min) min = p; else if (p > max) max = p; } return (new float[2] { min, max }); } public Paddle(Game game, bool isLeftPaddle, bool enableKeyboard = true) : base(game) { contentManager = new ContentManager(game.Services); keybEnabled = enableKeyboard; this.isLeftPaddle = isLeftPaddle; } public void setPosition(Vector2 newPos) { X = newPos.X; Y = newPos.Y; } public override void Initialize() { base.Initialize(); this.Speed = DEFAULT_Y_SPEED; X = 0; Y = 0; NormalsToEdges(this.isLeftPaddle); } protected override void LoadContent() { spriteBatch = new SpriteBatch(GraphicsDevice); paddleSprite = contentManager.Load<Texture2D>(@"Content\pongBar"); } public override void Update(GameTime gameTime) { //vertices array Vertices[0] = this.paddlePosition; Vertices[1] = this.paddlePosition + new Vector2(this.Width, 0); Vertices[2] = this.paddlePosition + new Vector2(this.Width, this.Height); Vertices[3] = this.paddlePosition + new Vector2(0, this.Height); // Move paddle, but don't allow movement off the screen if (KeyboardEnabled) { float moveDistance = Speed * (float)gameTime.ElapsedGameTime.TotalSeconds; KeyboardState newKeyState = Keyboard.GetState(); if (newKeyState.IsKeyDown(Keys.Down) && Y + paddleSprite.Height + moveDistance <= Game.GraphicsDevice.Viewport.Height) { Y += moveDistance; } else if (newKeyState.IsKeyDown(Keys.Up) && Y - moveDistance >= 0) { Y -= moveDistance; } } else { if (this.Y + this.Height > this.GraphicsDevice.Viewport.Height) { this.Y = this.Game.GraphicsDevice.Viewport.Height - this.Height - 1; } } base.Update(gameTime); } public override void Draw(GameTime gameTime) { spriteBatch.Begin(SpriteSortMode.Texture,null); spriteBatch.Draw(paddleSprite, paddlePosition, null, Color.White, 0f, Vector2.Zero, Scale, SpriteEffects.None, 0); spriteBatch.End(); base.Draw(gameTime); } } Ball Class public class Ball : Microsoft.Xna.Framework.DrawableGameComponent { #region Private Members private SpriteBatch spriteBatch; private ContentManager contentManager; private const float DEFAULT_SPEED = 50; private float speedIncrement = 0; private Vector2 ballScale = new Vector2(1f, 1f); private const float INCREASE_SPEED = 50; private Texture2D ballSprite; //initial texture private Vector2 ballPosition; //position private Vector2 centerOfBall; //center coords private Vector2 ballSpeed = new Vector2(DEFAULT_SPEED, DEFAULT_SPEED); //speed #endregion #region Properties public float DEFAULTSPEED { get { return DEFAULT_SPEED; } } public Vector2 ballCenter { get { return centerOfBall; } } public Vector2 Scale { get { return ballScale; } set { ballScale = value; } } public float SpeedX { get { return ballSpeed.X; } set { ballSpeed.X = value; } } public float SpeedY { get { return ballSpeed.Y; } set { ballSpeed.Y = value; } } public float X { get { return ballPosition.X; } set { ballPosition.X = value; } } public float Y { get { return ballPosition.Y; } set { ballPosition.Y = value; } } public Texture2D GetSprite { get { return ballSprite; } } public float Width { get { return (Scale.X == 1f ? (float)ballSprite.Width : ballSprite.Width * Scale.X); } } public float Height { get { return (Scale.Y == 1f ? (float)ballSprite.Height : ballSprite.Height * Scale.Y); } } public float SpeedIncreaseIncrement { get { return speedIncrement; } set { speedIncrement = value; } } public Rectangle Boundary { get { return new Rectangle((int)ballPosition.X, (int)ballPosition.Y, (int)this.Width, (int)this.Height); } } #endregion public Ball(Game game) : base(game) { contentManager = new ContentManager(game.Services); } public void Reset() { ballSpeed.X = DEFAULT_SPEED; ballSpeed.Y = DEFAULT_SPEED; ballPosition.X = Game.GraphicsDevice.Viewport.Width / 2 - ballSprite.Width / 2; ballPosition.Y = Game.GraphicsDevice.Viewport.Height / 2 - ballSprite.Height / 2; } public void SpeedUp() { if (ballSpeed.Y < 0) ballSpeed.Y -= (INCREASE_SPEED + speedIncrement); else ballSpeed.Y += (INCREASE_SPEED + speedIncrement); if (ballSpeed.X < 0) ballSpeed.X -= (INCREASE_SPEED + speedIncrement); else ballSpeed.X += (INCREASE_SPEED + speedIncrement); } public float[] ProjectBall(Vector2 axis) { if (axis == Vector2.Zero) return (new float[2] { 0, 0 }); float min, max; min = Vector2.Dot(axis, this.ballCenter) - this.Width/2; //center - radius max = min + this.Width; //center + radius return (new float[2] { min, max }); } public void ChangeHorzDirection() { ballSpeed.X *= -1; } public void ChangeVertDirection() { ballSpeed.Y *= -1; } public override void Initialize() { base.Initialize(); ballPosition.X = Game.GraphicsDevice.Viewport.Width / 2 - ballSprite.Width / 2; ballPosition.Y = Game.GraphicsDevice.Viewport.Height / 2 - ballSprite.Height / 2; } protected override void LoadContent() { spriteBatch = new SpriteBatch(GraphicsDevice); ballSprite = contentManager.Load<Texture2D>(@"Content\ball"); } public override void Update(GameTime gameTime) { if (this.Y < 1 || this.Y > GraphicsDevice.Viewport.Height - this.Height - 1) this.ChangeVertDirection(); centerOfBall = new Vector2(ballPosition.X + this.Width / 2, ballPosition.Y + this.Height / 2); base.Update(gameTime); } public override void Draw(GameTime gameTime) { spriteBatch.Begin(); spriteBatch.Draw(ballSprite, ballPosition, null, Color.White, 0f, Vector2.Zero, Scale, SpriteEffects.None, 0); spriteBatch.End(); base.Draw(gameTime); } } Main game class public class gameStart : Microsoft.Xna.Framework.Game { GraphicsDeviceManager graphics; SpriteBatch spriteBatch; public gameStart() { graphics = new GraphicsDeviceManager(this); Content.RootDirectory = "Content"; this.Window.Title = "Pong game"; } protected override void Initialize() { ball = new Ball(this); paddleLeft = new Paddle(this,true,false); paddleRight = new Paddle(this,false,true); Components.Add(ball); Components.Add(paddleLeft); Components.Add(paddleRight); this.Window.AllowUserResizing = false; this.IsMouseVisible = true; this.IsFixedTimeStep = false; this.isColliding = false; base.Initialize(); } #region MyPrivateStuff private Ball ball; private Paddle paddleLeft, paddleRight; private int[] bit = { -1, 1 }; private Random rnd = new Random(); private int updates = 0; enum nrPaddle { None, Left, Right }; private nrPaddle PongBar = nrPaddle.None; private ArrayList Axes = new ArrayList(); private Vector2 MTV; //minimum translation vector private bool isColliding; private float overlap; //smallest distance after projections private Vector2 overlapAxis; //axis of overlap #endregion protected override void LoadContent() { spriteBatch = new SpriteBatch(GraphicsDevice); paddleLeft.setPosition(new Vector2(0, this.GraphicsDevice.Viewport.Height / 2 - paddleLeft.Height / 2)); paddleRight.setPosition(new Vector2(this.GraphicsDevice.Viewport.Width - paddleRight.Width, this.GraphicsDevice.Viewport.Height / 2 - paddleRight.Height / 2)); paddleLeft.Scale = new Vector2(1f, 2f); //scale left paddle } private bool ShapesIntersect(Paddle paddle, Ball ball) { overlap = 1000000f; //large value overlapAxis = Vector2.Zero; MTV = Vector2.Zero; foreach (Vector2 ax in Axes) { float[] pad = paddle.ProjectPaddle(ax); //pad0 = min, pad1 = max float[] circle = ball.ProjectBall(ax); //circle0 = min, circle1 = max if (pad[1] <= circle[0] || circle[1] <= pad[0]) { return false; } if (pad[1] - circle[0] < circle[1] - pad[0]) { if (Math.Abs(overlap) > Math.Abs(-pad[1] + circle[0])) { overlap = -pad[1] + circle[0]; overlapAxis = ax; } } else { if (Math.Abs(overlap) > Math.Abs(circle[1] - pad[0])) { overlap = circle[1] - pad[0]; overlapAxis = ax; } } } if (overlapAxis != Vector2.Zero) { MTV = overlapAxis * overlap; } return true; } protected override void Update(GameTime gameTime) { updates += 1; float ftime = 5 * (float)gameTime.ElapsedGameTime.TotalSeconds; if (updates == 1) { isColliding = false; int Xrnd = bit[Convert.ToInt32(rnd.Next(0, 2))]; int Yrnd = bit[Convert.ToInt32(rnd.Next(0, 2))]; ball.SpeedX = Xrnd * ball.SpeedX; ball.SpeedY = Yrnd * ball.SpeedY; ball.X += ftime * ball.SpeedX; ball.Y += ftime * ball.SpeedY; } else { updates = 100; ball.X += ftime * ball.SpeedX; ball.Y += ftime * ball.SpeedY; } //autorun :) paddleLeft.Y = ball.Y; //collision detection PongBar = nrPaddle.None; if (ball.Boundary.Intersects(paddleLeft.Boundary)) { PongBar = nrPaddle.Left; if (!isColliding) { Axes.Clear(); Axes.AddRange(paddleLeft.Normal2EdgesVector); //axis from nearest vertex to ball's center Axes.Add(FORMULAS.NormAxisFromCircle2ClosestVertex(paddleLeft.VertexVector, ball.ballCenter)); } } else if (ball.Boundary.Intersects(paddleRight.Boundary)) { PongBar = nrPaddle.Right; if (!isColliding) { Axes.Clear(); Axes.AddRange(paddleRight.Normal2EdgesVector); //axis from nearest vertex to ball's center Axes.Add(FORMULAS.NormAxisFromCircle2ClosestVertex(paddleRight.VertexVector, ball.ballCenter)); } } if (PongBar != nrPaddle.None && !isColliding) switch (PongBar) { case nrPaddle.Left: if (ShapesIntersect(paddleLeft, ball)) { isColliding = true; if (MTV != Vector2.Zero) ball.X += MTV.X; ball.Y += MTV.Y; ball.ChangeHorzDirection(); } break; case nrPaddle.Right: if (ShapesIntersect(paddleRight, ball)) { isColliding = true; if (MTV != Vector2.Zero) ball.X += MTV.X; ball.Y += MTV.Y; ball.ChangeHorzDirection(); } break; default: break; } if (!ShapesIntersect(paddleRight, ball) && !ShapesIntersect(paddleLeft, ball)) isColliding = false; ball.X += ftime * ball.SpeedX; ball.Y += ftime * ball.SpeedY; //check ball movement if (ball.X > paddleRight.X + paddleRight.Width + 2) { //IncreaseScore(Left); ball.Reset(); updates = 0; return; } else if (ball.X < paddleLeft.X - 2) { //IncreaseScore(Right); ball.Reset(); updates = 0; return; } base.Update(gameTime); } protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.Aquamarine); spriteBatch.Begin(SpriteSortMode.BackToFront, BlendState.AlphaBlend); spriteBatch.End(); base.Draw(gameTime); } } And one method i've used: public static Vector2 NormAxisFromCircle2ClosestVertex(Vector2[] vertices, Vector2 circle) { Vector2 temp = Vector2.Zero; if (vertices.Length > 0) { float dist = (circle.X - vertices[0].X) * (circle.X - vertices[0].X) + (circle.Y - vertices[0].Y) * (circle.Y - vertices[0].Y); for (int i = 1; i < vertices.Length;i++) { if (dist > (circle.X - vertices[i].X) * (circle.X - vertices[i].X) + (circle.Y - vertices[i].Y) * (circle.Y - vertices[i].Y)) { temp = vertices[i]; //memorize the closest vertex dist = (circle.X - vertices[i].X) * (circle.X - vertices[i].X) + (circle.Y - vertices[i].Y) * (circle.Y - vertices[i].Y); } } temp = circle - temp; temp.Normalize(); } return temp; } Thanks in advance for any tips on the 4 issues. EDIT1: Something isn't working properly. The collision axis doesn't come out right and the interpolation also seems to have no effect. I've changed the code a bit: private bool ShapesIntersect(Paddle paddle, Ball ball) { overlap = 1000000f; //large value overlapAxis = Vector2.Zero; MTV = Vector2.Zero; foreach (Vector2 ax in Axes) { float[] pad = paddle.ProjectPaddle(ax); //pad0 = min, pad1 = max float[] circle = ball.ProjectBall(ax); //circle0 = min, circle1 = max if (pad[1] < circle[0] || circle[1] < pad[0]) { return false; } if (Math.Abs(pad[1] - circle[0]) < Math.Abs(circle[1] - pad[0])) { if (Math.Abs(overlap) > Math.Abs(-pad[1] + circle[0])) { overlap = -pad[1] + circle[0]; overlapAxis = ax * (-1); } //to get the proper axis } else { if (Math.Abs(overlap) > Math.Abs(circle[1] - pad[0])) { overlap = circle[1] - pad[0]; overlapAxis = ax; } } } if (overlapAxis != Vector2.Zero) { MTV = overlapAxis * Math.Abs(overlap); } return true; } And part of the Update method: if (ShapesIntersect(paddleRight, ball)) { isColliding = true; if (MTV != Vector2.Zero) { ball.X += MTV.X; ball.Y += MTV.Y; } //test if (overlapAxis.X == 0) //collision with horizontal edge { } else if (overlapAxis.Y == 0) //collision with vertical edge { float factor = Math.Abs(ball.ballCenter.Y - paddleRight.Y) / paddleRight.Height; if (factor > 1) factor = 1f; if (overlapAxis.X < 0) //left edge? ball.Speed = ball.DEFAULTSPEED * Vector2.Normalize(Vector2.Reflect(ball.Speed, (Vector2.Lerp(new Vector2(-1, -3), new Vector2(-1, 3), factor)))); else //right edge? ball.Speed = ball.DEFAULTSPEED * Vector2.Normalize(Vector2.Reflect(ball.Speed, (Vector2.Lerp(new Vector2(1, -3), new Vector2(1, 3), factor)))); } else //vertex collision??? { ball.Speed = -ball.Speed; } } What seems to happen is that "overlapAxis" doesn't always return the right one. So instead of (-1,0) i get the (1,0) (this happened even before i multiplied with -1 there). Sometimes there isn't even a collision registered even though the ball passes through the paddle... The interpolation also seems to have no effect as the angles barely change (or the overlapAxis is almost never (-1,0) or (1,0) but something like (0.9783473, 0.02743843)... ). What am i missing here? :(

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  • Using CSS, how can I make overflow:visible; contents overlap adjacent <td> cells?

    - by Structure
    I have the following CSS style code for my table: td { overflow: hidden; white-space:nowrap; } td:hover { overflow: visible; } However, when I hover over a <td> element whos contents (text) are hidden, the result is that the contents become visible but are behind the content of the adjacent cell (right side). I do not think that z-index can be applied to table cell elements, so is there a CSS attribute that I can specify within my td:hover style which will make the content of my <td> tag overlap the content in adjacent cells?

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  • CSS: How the backgrounds can extend the border and overlap?

    - by AlexStack
    I'm designing a navigation bar as shown in image below (a) with the following code: <ul> <li class="unselected">Step 1</li> <li class="selected">Step 2</li> <li class="unselected">Step 3</li> <li class="unselected">Step 4</li> <li class="unselected">Step 5</li> </ul> I want to have one background image for unselected steps (d) and one for the selected step (c). For simplicity let's assume Step 1 and Step 5 use the same background as well. I want to adjust the button background in HTML only with a class name. The question is how can I achieve the result with CSS? I just want to know how background of two neighbor elements can overlap each other?

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  • Trying to detect collision between two polygons using Separating Axis Theorem

    - by Holly
    The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(vertices[0]); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(vertices[i]); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if( other.x <= y || other.y >= x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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  • Error in my Separating Axis Theorem collision code

    - by Holly
    The only collision experience i've had was with simple rectangles, i wanted to find something that would allow me to define polygonal areas for collision and have been trying to make sense of SAT using these two links Though i'm a bit iffy with the math for the most part i feel like i understand the theory! Except my implementation somewhere down the line must be off as: (excuse the hideous font) As mentioned above i have defined a CollisionPolygon class where most of my theory is implemented and then have a helper class called Vect which was meant to be for Vectors but has also been used to contain a vertex given that both just have two float values. I've tried stepping through the function and inspecting the values to solve things but given so many axes and vectors and new math to work out as i go i'm struggling to find the erroneous calculation(s) and would really appreciate any help. Apologies if this is not suitable as a question! CollisionPolygon.java: package biz.hireholly.gameplay; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import biz.hireholly.gameplay.Types.Vect; public class CollisionPolygon { Paint paint; private Vect[] vertices; private Vect[] separationAxes; int x; int y; CollisionPolygon(Vect[] vertices){ this.vertices = vertices; //compute edges and separations axes separationAxes = new Vect[vertices.length]; for (int i = 0; i < vertices.length; i++) { // get the current vertex Vect p1 = vertices[i]; // get the next vertex Vect p2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; // subtract the two to get the edge vector Vect edge = p1.subtract(p2); // get either perpendicular vector Vect normal = edge.perp(); // the perp method is just (x, y) => (-y, x) or (y, -x) separationAxes[i] = normal; } paint = new Paint(); paint.setColor(Color.RED); } public void draw(Canvas c, int xPos, int yPos){ for (int i = 0; i < vertices.length; i++) { Vect v1 = vertices[i]; Vect v2 = vertices[i + 1 == vertices.length ? 0 : i + 1]; c.drawLine( xPos + v1.x, yPos + v1.y, xPos + v2.x, yPos + v2.y, paint); } } public void update(int xPos, int yPos){ x = xPos; y = yPos; } /* consider changing to a static function */ public boolean intersects(CollisionPolygon p){ // loop over this polygons separation exes for (Vect axis : separationAxes) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // loop over the other polygons separation axes Vect[] sepAxesOther = p.getSeparationAxes(); for (Vect axis : sepAxesOther) { // project both shapes onto the axis Vect p1 = this.minMaxProjection(axis); Vect p2 = p.minMaxProjection(axis); // do the projections overlap? if (!p1.overlap(p2)) { // then we can guarantee that the shapes do not overlap return false; } } // if we get here then we know that every axis had overlap on it // so we can guarantee an intersection return true; } /* Note projections wont actually be acurate if the axes aren't normalised * but that's not necessary since we just need a boolean return from our * intersects not a Minimum Translation Vector. */ private Vect minMaxProjection(Vect axis) { float min = axis.dot(new Vect(vertices[0].x+x, vertices[0].y+y)); float max = min; for (int i = 1; i < vertices.length; i++) { float p = axis.dot(new Vect(vertices[i].x+x, vertices[i].y+y)); if (p < min) { min = p; } else if (p > max) { max = p; } } Vect minMaxProj = new Vect(min, max); return minMaxProj; } public Vect[] getSeparationAxes() { return separationAxes; } public Vect[] getVertices() { return vertices; } } Vect.java: package biz.hireholly.gameplay.Types; /* NOTE: Can also be used to hold vertices! Projections, coordinates ect */ public class Vect{ public float x; public float y; public Vect(float x, float y){ this.x = x; this.y = y; } public Vect perp() { return new Vect(-y, x); } public Vect subtract(Vect other) { return new Vect(x - other.x, y - other.y); } public boolean overlap(Vect other) { if(y > other.x && other.y > x){ return true; } return false; } /* used specifically for my SAT implementation which i'm figuring out as i go, * references for later.. * http://www.gamedev.net/page/resources/_/technical/game-programming/2d-rotated-rectangle-collision-r2604 * http://www.codezealot.org/archives/55 */ public float scalarDotProjection(Vect other) { //multiplier = dot product / length^2 float multiplier = dot(other) / (x*x + y*y); //to get the x/y of the projection vector multiply by x/y of axis float projX = multiplier * x; float projY = multiplier * y; //we want to return the dot product of the projection, it's meaningless but useful in our SAT case return dot(new Vect(projX,projY)); } public float dot(Vect other){ return (other.x*x + other.y*y); } }

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