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  • AS3 - At exactly 23 empty alpha channels, images below stop drawing

    - by user46851
    I noticed, while trying to draw large numbers of circles, that occasionally, there would be some kind of visual bug where some circles wouldn't draw properly. Well, I narrowed it down, and have noticed that if there is 23 or more objects with 00 for an alpha value on the same spot, then the objects below don't draw. It appears to be on a pixel-by-pixel basis, since parts of the image still draw. Originally, this problem was noticed with a class that inherited Sprite. It was confirmed to also be a problem with Sprites, and now Bitmaps, too. If anyone can find a lower-level class than Bitmap which doesn't have this problem, please speak up so we can try to find the origin of the problem. I prepared a small test class that demonstrates what I mean. You can change the integer value at line 20 in order to see the three tests I came up with to clearly show the problem. Is there any kind of workaround, or is this just a limit that I have to work with? Has anyone experienced this before? Is it possible I'm doing something wrong, despite the bare-bones implementation? package { import flash.display.Sprite; import flash.events.Event; import flash.display.Bitmap; import flash.display.BitmapData; public class Main extends Sprite { public function Main():void { if (stage) init(); else addEventListener(Event.ADDED_TO_STAGE, init); } private function init(e:Event = null):void { removeEventListener(Event.ADDED_TO_STAGE, init); // entry point Test(3); } private function Test(testInt:int):void { if(testInt==1){ addChild(new Bitmap(new BitmapData(200, 200, true, 0xFFFF0000))); for (var i:int = 0; i < 22; i++) { addChild(new Bitmap(new BitmapData(100, 100, true, 0x00000000))); } } if(testInt==2){ addChild(new Bitmap(new BitmapData(200, 200, true, 0xFFFF0000))); for (var j:int = 0; j < 23; j++) { addChild(new Bitmap(new BitmapData(100, 100, true, 0x00000000))); } } if(testInt==3){ addChild(new Bitmap(new BitmapData(200, 200, true, 0xFFFF0000))); for (var k:int = 0; k < 22; k++) { addChild(new Bitmap(new BitmapData(100, 100, true, 0x00000000))); } var M:Bitmap = new Bitmap(new BitmapData(100, 100, true, 0x00000000)); M.x += 50; M.y += 50; addChild(M); } } } }

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  • Detect click on Triangle and Circle buttons

    - by chr1s89
    How can i detect clicks on a texture (will be a button in my game) that has a form of a triangle or circle. I know only the rectangle solution where u can use the positions + the width/height but this dont work for that because clicks will be detected at the transparent pixels. I heard of pixel-perfect collision is it the right way for this? It would be great if someone can give me a example for such a solution or other.

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  • How can I plot a radius of all reachable points with pathfinding for a Mob (XNA)?

    - by PugWrath
    I am designing a tactical turn based game. The maps are 2d, but do have varying level-layers and blocking objects/terrain. I'm looking for an algorithm for pathfinding which will allow me to show an opaque shape representing all of the possible max-distance pixels that a mob can move to, knowing the mob's max pixel distance. Any thoughts on this, or do I just need to write a good pathfinding algorithm and use it to find the cutoff points for any direction in which an obstacle exists?

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  • CSS hack for Google Chrome and Safari

    - by Renso
    When wanting to hack css in an external stylesheet just for Google Chrome and Safari. Here is an example of where I override the margin-top for Chrome and Safari.Normal:#AccountMaintenanceWrapper #callDetailsPreviewWrapper{    border: none;    padding: 0px;    width: 209px;    position: fixed;    margin-top: 84px;    z-index: 1;}Google Chrome and Safari:@media screen and (-webkit-min-device-pixel-ratio:0){    #AccountMaintenanceWrapper #callDetailsPreviewWrapper    {        margin-top: 12px;    }}

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  • XNA - Detect click on triangle/circle form of a texture

    - by chr1s89
    How can i detect clicks on a texture (will be a button in my game) that has a form of a triangle or circle. I know only the rectangle solution where u can use the positions + the width/height but this dont work for that because clicks will be detected at the transparent pixels. I heard of pixel-perfect collision is it the right way for this? It would be great if someone can give me a example for such a solution or other.

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  • VNC error: "Could not connect to session bus: Failed to connect to socket"

    - by GJ
    I started a vncserver on display :1 on an ubuntu machine. When I connect to it, I get a grey X window with an error message Could not connect to session bus: Failed to connect to socket. The vnc log is: Xvnc Free Edition 4.1.1 - built Apr 9 2010 15:59:33 Copyright (C) 2002-2005 RealVNC Ltd. See http://www.realvnc.com for information on VNC. Underlying X server release 40300000, The XFree86 Project, Inc Sun Mar 20 15:33:59 2011 vncext: VNC extension running! vncext: Listening for VNC connections on port 5901 vncext: created VNC server for screen 0 error opening security policy file /etc/X11/xserver/SecurityPolicy Could not init font path element /usr/X11R6/lib/X11/fonts/Type1/, removing from list! Could not init font path element /usr/X11R6/lib/X11/fonts/Speedo/, removing from list! Could not init font path element /usr/X11R6/lib/X11/fonts/misc/, removing from list! Could not init font path element /usr/X11R6/lib/X11/fonts/75dpi/, removing from list! Could not init font path element /usr/X11R6/lib/X11/fonts/100dpi/, removing from list! cat: /var/run/gdm/auth-for-link2-eGnVvf/database: No such file or directory gnome-session[24880]: WARNING: Could not make bus activated clients aware of DISPLAY=:1.0 environment variable: Failed to connect to socket /tmp/dbus-FhdHHIq8jt: Connection refused gnome-session[24880]: WARNING: Could not make bus activated clients aware of GNOME_DESKTOP_SESSION_ID=this-is-deprecated environment variable: Failed to connect to socket /tmp/dbus-FhdHHIq8jt: Connection refused gnome-session[24880]: WARNING: Could not make bus activated clients aware of SESSION_MANAGER=local/dell:@/tmp/.ICE-unix/24880,unix/dell:/tmp/.ICE-unix/24880 environment variable: Failed to connect to socket /tmp/dbus-FhdHHIq8jt: Connection refused Sun Mar 20 15:34:10 2011 Connections: accepted: 0.0.0.0::51620 SConnection: Client needs protocol version 3.8 SConnection: Client requests security type VncAuth(2) VNCSConnST: Server default pixel format depth 16 (16bpp) little-endian rgb565 VNCSConnST: Client pixel format depth 16 (16bpp) little-endian rgb565 gnome-session[24880]: Gtk-CRITICAL: gtk_main_quit: assertion `main_loops != NULL' failed gnome-session[24880]: CRITICAL: dbus_g_proxy_new_for_name: assertion `connection != NULL' failed Any ideas how to fix it?

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  • converting a png with an ICC profile?

    - by jedierikb
    I can convert a jpg from one ICC to another ICC. convert rgb_image.jpg -profile USCoat.icm cmyk_image.jpg Or I can convert a jpg with no ICC to another ICC. convert rgb_image.jpg +profile icm \ -profile sRGB.icc -profile USCoat.icm cmyk_image.jpg But how do I convert a png's pixels into the gamut described by an ICC profile? I understand I cannot embed the profile into the image file, but would at least like to convert the colors. When I reuse the above commands, the colors come out wrong... (different from the colors in the JPG when converted). This is the source image: http://alumni.media.mit.edu/~erikb/tmp/RED_JPG.jpg And here is what I am trying: convert RED_JPG.jpg +profile icm -profile sRGB_v4_ICC_preference.icc -profile USWebUncoated.icc CMYK_PNG.png and this is what I am getting: http://alumni.media.mit.edu/~erikb/tmp/CMYK_PNG.png I was hoping to get an image with the same colors as a JPEG run through the same command: convert RED_JPG.jpg +profile icm -profile sRGB_v4_ICC_preference.icc -profile USWebUncoated.icc CMYK_JPG.jpg resulting in: http://alumni.media.mit.edu/~erikb/tmp/CMYK_JPG.jpg *this image, CMYK_JPG.jpg, is what I am trying to reproduce pixel by pixel in a PNG file.* Any suggestions? Original (unanswered) post here.

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  • Green flickering pixels that move with black images

    - by user568458
    Strange question... Occasionally, on my LCD screen, pixels that should be black flicker rapidly and constantly between black and green, about 4 flickers a second. The crazy part is, unlike dead/stuck pixels, they are relative to content on the screen and move with it. For example, I might be looking at a web page with a picture that has lots of black. There might be a couple of green flashing pixels in that black that shouldn't be there. I scroll the page, and the green flickering pixels move with the image. It seems that everyphysical pixel is fine, but somehow something interprets part of the image in a way that causes flickering green... It's not just in a web browser. My first thought was to blame a trolling blogger cunningly uploading an animated gif that simulates a failing pixel... but it happens in a wide range of applications. It seems to occur randomly, other than that it seems to only occur in areas of pure black, and it's always pure 100% green. It happens rarely enough that it's not a big deal, but it's such a strange problem it bugs me. I can't find any info on anything like this. I'm not even sure if it's hardware or software. Any ideas? (windows 7 laptop connected to LCD by DVI to HDMI cable)

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  • Prevent Outlook 2010 Insert Picture resizing image

    - by Rup
    When I "Insert Picture" a JPEG in Outlook 2010 it automatically resizes the image and, I think, recompresses it too. I realise this would be useful for photographs or for people who try to email 1MB BMPs but I would like to email around an image at the original pixel size without recompression. Is there a way to turn this off, or better still choose settings for each image insert? I found this page in the Office help. It's for Word, PowerPoint and Excel not Outlook but points you at File, Options, Advanced, Image Settings. There's no equivalent section in Outlook. I know Outlook uses Word as its editor so I've looked at Word's settings but there isn't an 'original size' here: there's only 'turn off image recompression' and pick target DPI from 96, 150, 220. I guess Office is finding a DPI value in the JPEG file and scaling it up or down to match this setting. I can't find an equivalent option in Outlook's options menu but there's so many settings and pop-up dialogs I may have missed something. Picture Format, Reset image size resets the image to the rescaled version, not the original. I can't see a way to edit a pixel value into size values in the image properties after insert. Thanks! I realise I can probably achieve this by editing the image metadata in PhotoShop elements or similar but there ought to be a way without editing the file? This is new behaviour in Outlook 2010; 2007 didn't do this.

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  • Why do moving lines become fuzzy on my monitor?

    - by CodeInChaos
    I recently got a new notebook. With moving images there are some graphical issues, and I'd like to know what causes them. None of my earlier monitors exhibited similar issues. Moving high contrast lines become jagged, similar to interleaved videos. When moving a horizontal line vertically those artifacts are colored, when moving a vertical line horizontally they aren't colored. The effect isn't observable in static images. And when moving faster the zone in which it occurs becomes wider. The effect is very visible if I move a window around on the borders of the window and wherever high contrast lines appear. But it appears when watching videos too. The vertical line in that image moves to the right, the horizontal line upwards. The effect is most likely related to the fact that each real pixel consists of different sub-pixels for the different color channels. But how are these causing the observed effect? Is the change at which the different colors change to the destination brightness different? The optical impression is that every second pixel in a chess board like arrangement is adapting slower than it's neighbors. But that doesn't make much sense.

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  • rotating bitmaps. In code.

    - by Marco van de Voort
    Is there a faster way to rotate a large bitmap by 90 or 270 degrees than simply doing a nested loop with inverted coordinates? The bitmaps are 8bpp and typically 2048*2400*8bpp Currently I do this by simply copying with argument inversion, roughly (pseudo code: for x = 0 to 2048-1 for y = 0 to 2048-1 dest[x][y]=src[y][x]; (In reality I do it with pointers, for a bit more speed, but that is roughly the same magnitude) GDI is quite slow with large images, and GPU load/store times for textures (GF7 cards) are in the same magnitude as the current CPU time. Any tips, pointers? An in-place algorithm would even be better, but speed is more important than being in-place. Target is Delphi, but it is more an algorithmic question. SSE(2) vectorization no problem, it is a big enough problem for me to code it in assembler Duplicates How do you rotate a two dimensional array?. Follow up to Nils' answer Image 2048x2700 - 2700x2048 Compiler Turbo Explorer 2006 with optimization on. Windows: Power scheme set to "Always on". (important!!!!) Machine: Core2 6600 (2.4 GHz) time with old routine: 32ms (step 1) time with stepsize 8 : 12ms time with stepsize 16 : 10ms time with stepsize 32+ : 9ms Meanwhile I also tested on a Athlon 64 X2 (5200+ iirc), and the speed up there was slightly more than a factor four (80 to 19 ms). The speed up is well worth it, thanks. Maybe that during the summer months I'll torture myself with a SSE(2) version. However I already thought about how to tackle that, and I think I'll run out of SSE2 registers for an straight implementation: for n:=0 to 7 do begin load r0, <source+n*rowsize> shift byte from r0 into r1 shift byte from r0 into r2 .. shift byte from r0 into r8 end; store r1, <target> store r2, <target+1*<rowsize> .. store r8, <target+7*<rowsize> So 8x8 needs 9 registers, but 32-bits SSE only has 8. Anyway that is something for the summer months :-) Note that the pointer thing is something that I do out of instinct, but it could be there is actually something to it, if your dimensions are not hardcoded, the compiler can't turn the mul into a shift. While muls an sich are cheap nowadays, they also generate more register pressure afaik. The code (validated by subtracting result from the "naieve" rotate1 implementation): const stepsize = 32; procedure rotatealign(Source: tbw8image; Target:tbw8image); var stepsx,stepsy,restx,resty : Integer; RowPitchSource, RowPitchTarget : Integer; pSource, pTarget,ps1,ps2 : pchar; x,y,i,j: integer; rpstep : integer; begin RowPitchSource := source.RowPitch; // bytes to jump to next line. Can be negative (includes alignment) RowPitchTarget := target.RowPitch; rpstep:=RowPitchTarget*stepsize; stepsx:=source.ImageWidth div stepsize; stepsy:=source.ImageHeight div stepsize; // check if mod 16=0 here for both dimensions, if so -> SSE2. for y := 0 to stepsy - 1 do begin psource:=source.GetImagePointer(0,y*stepsize); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(target.imagewidth-(y+1)*stepsize,0); for x := 0 to stepsx - 1 do begin for i := 0 to stepsize - 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[stepsize-1-i]; // (maxx-i,0); for j := 0 to stepsize - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize); inc(ptarget,rpstep); end; end; // 3 more areas to do, with dimensions // - stepsy*stepsize * restx // right most column of restx width // - stepsx*stepsize * resty // bottom row with resty height // - restx*resty // bottom-right rectangle. restx:=source.ImageWidth mod stepsize; // typically zero because width is // typically 1024 or 2048 resty:=source.Imageheight mod stepsize; if restx>0 then begin // one loop less, since we know this fits in one line of "blocks" psource:=source.GetImagePointer(source.ImageWidth-restx,0); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(Target.imagewidth-stepsize,Target.imageheight-restx); for y := 0 to stepsy - 1 do begin for i := 0 to stepsize - 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[stepsize-1-i]; // (maxx-i,0); for j := 0 to restx - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize*RowPitchSource); dec(ptarget,stepsize); end; end; if resty>0 then begin // one loop less, since we know this fits in one line of "blocks" psource:=source.GetImagePointer(0,source.ImageHeight-resty); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(0,0); for x := 0 to stepsx - 1 do begin for i := 0 to resty- 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[resty-1-i]; // (maxx-i,0); for j := 0 to stepsize - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; inc(psource,stepsize); inc(ptarget,rpstep); end; end; if (resty>0) and (restx>0) then begin // another loop less, since only one block psource:=source.GetImagePointer(source.ImageWidth-restx,source.ImageHeight-resty); // gets pointer to pixel x,y ptarget:=Target.GetImagePointer(0,target.ImageHeight-restx); for i := 0 to resty- 1 do begin ps1:=@psource[rowpitchsource*i]; // ( 0,i) ps2:=@ptarget[resty-1-i]; // (maxx-i,0); for j := 0 to restx - 1 do begin ps2[0]:=ps1[j]; inc(ps2,RowPitchTarget); end; end; end; end;

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  • Access violation in DirectX OMSetRenderTargets

    - by IDWMaster
    I receive the following error (Unhandled exception at 0x527DAE81 (d3d11_1sdklayers.dll) in Lesson2.Triangles.exe: 0xC0000005: Access violation reading location 0x00000000) when running the Triangle sample application for DirectX 11 in D3D_FEATURE_LEVEL_9_1. This error occurs at the OMSetRenderTargets function, as shown below, and does not happen if I remove that function from the program (but then, the screen is blue, and does not render the triangle) //// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF //// ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO //// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A //// PARTICULAR PURPOSE. //// //// Copyright (c) Microsoft Corporation. All rights reserved #include #include #include "DirectXSample.h" #include "BasicMath.h" #include "BasicReaderWriter.h" using namespace Microsoft::WRL; using namespace Windows::UI::Core; using namespace Windows::Foundation; using namespace Windows::ApplicationModel::Core; using namespace Windows::ApplicationModel::Infrastructure; // This class defines the application as a whole. ref class Direct3DTutorialViewProvider : public IViewProvider { private: CoreWindow^ m_window; ComPtr m_swapChain; ComPtr m_d3dDevice; ComPtr m_d3dDeviceContext; ComPtr m_renderTargetView; public: // This method is called on application launch. void Initialize( _In_ CoreWindow^ window, _In_ CoreApplicationView^ applicationView ) { m_window = window; } // This method is called after Initialize. void Load(_In_ Platform::String^ entryPoint) { } // This method is called after Load. void Run() { // First, create the Direct3D device. // This flag is required in order to enable compatibility with Direct2D. UINT creationFlags = D3D11_CREATE_DEVICE_BGRA_SUPPORT; #if defined(_DEBUG) // If the project is in a debug build, enable debugging via SDK Layers with this flag. creationFlags |= D3D11_CREATE_DEVICE_DEBUG; #endif // This array defines the ordering of feature levels that D3D should attempt to create. D3D_FEATURE_LEVEL featureLevels[] = { D3D_FEATURE_LEVEL_11_1, D3D_FEATURE_LEVEL_11_0, D3D_FEATURE_LEVEL_10_1, D3D_FEATURE_LEVEL_10_0, D3D_FEATURE_LEVEL_9_3, D3D_FEATURE_LEVEL_9_1 }; ComPtr d3dDevice; ComPtr d3dDeviceContext; DX::ThrowIfFailed( D3D11CreateDevice( nullptr, // specify nullptr to use the default adapter D3D_DRIVER_TYPE_HARDWARE, nullptr, // leave as nullptr if hardware is used creationFlags, // optionally set debug and Direct2D compatibility flags featureLevels, ARRAYSIZE(featureLevels), D3D11_SDK_VERSION, // always set this to D3D11_SDK_VERSION &d3dDevice, nullptr, &d3dDeviceContext ) ); // Retrieve the Direct3D 11.1 interfaces. DX::ThrowIfFailed( d3dDevice.As(&m_d3dDevice) ); DX::ThrowIfFailed( d3dDeviceContext.As(&m_d3dDeviceContext) ); // After the D3D device is created, create additional application resources. CreateWindowSizeDependentResources(); // Create a Basic Reader-Writer class to load data from disk. This class is examined // in the Resource Loading sample. BasicReaderWriter^ reader = ref new BasicReaderWriter(); // Load the raw vertex shader bytecode from disk and create a vertex shader with it. auto vertexShaderBytecode = reader-ReadData("SimpleVertexShader.cso"); ComPtr vertexShader; DX::ThrowIfFailed( m_d3dDevice-CreateVertexShader( vertexShaderBytecode-Data, vertexShaderBytecode-Length, nullptr, &vertexShader ) ); // Create an input layout that matches the layout defined in the vertex shader code. // For this lesson, this is simply a float2 vector defining the vertex position. const D3D11_INPUT_ELEMENT_DESC basicVertexLayoutDesc[] = { { "POSITION", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0 }, }; ComPtr inputLayout; DX::ThrowIfFailed( m_d3dDevice-CreateInputLayout( basicVertexLayoutDesc, ARRAYSIZE(basicVertexLayoutDesc), vertexShaderBytecode-Data, vertexShaderBytecode-Length, &inputLayout ) ); // Load the raw pixel shader bytecode from disk and create a pixel shader with it. auto pixelShaderBytecode = reader-ReadData("SimplePixelShader.cso"); ComPtr pixelShader; DX::ThrowIfFailed( m_d3dDevice-CreatePixelShader( pixelShaderBytecode-Data, pixelShaderBytecode-Length, nullptr, &pixelShader ) ); // Create vertex and index buffers that define a simple triangle. float3 triangleVertices[] = { float3(-0.5f, -0.5f,13.5f), float3( 0.0f, 0.5f,0), float3( 0.5f, -0.5f,0), }; D3D11_BUFFER_DESC vertexBufferDesc = {0}; vertexBufferDesc.ByteWidth = sizeof(float3) * ARRAYSIZE(triangleVertices); vertexBufferDesc.Usage = D3D11_USAGE_DEFAULT; vertexBufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER; vertexBufferDesc.CPUAccessFlags = 0; vertexBufferDesc.MiscFlags = 0; vertexBufferDesc.StructureByteStride = 0; D3D11_SUBRESOURCE_DATA vertexBufferData; vertexBufferData.pSysMem = triangleVertices; vertexBufferData.SysMemPitch = 0; vertexBufferData.SysMemSlicePitch = 0; ComPtr vertexBuffer; DX::ThrowIfFailed( m_d3dDevice-CreateBuffer( &vertexBufferDesc, &vertexBufferData, &vertexBuffer ) ); // Once all D3D resources are created, configure the application window. // Allow the application to respond when the window size changes. m_window-SizeChanged += ref new TypedEventHandler( this, &Direct3DTutorialViewProvider::OnWindowSizeChanged ); // Specify the cursor type as the standard arrow cursor. m_window-PointerCursor = ref new CoreCursor(CoreCursorType::Arrow, 0); // Activate the application window, making it visible and enabling it to receive events. m_window-Activate(); // Enter the render loop. Note that tailored applications should never exit. while (true) { // Process events incoming to the window. m_window-Dispatcher-ProcessEvents(CoreProcessEventsOption::ProcessAllIfPresent); // Specify the render target we created as the output target. ID3D11RenderTargetView* targets[1] = {m_renderTargetView.Get()}; m_d3dDeviceContext-OMSetRenderTargets( 1, targets, NULL // use no depth stencil ); // Clear the render target to a solid color. const float clearColor[4] = { 0.071f, 0.04f, 0.561f, 1.0f }; //Code fails here m_d3dDeviceContext-ClearRenderTargetView( m_renderTargetView.Get(), clearColor ); m_d3dDeviceContext-IASetInputLayout(inputLayout.Get()); // Set the vertex and index buffers, and specify the way they define geometry. UINT stride = sizeof(float3); UINT offset = 0; m_d3dDeviceContext-IASetVertexBuffers( 0, 1, vertexBuffer.GetAddressOf(), &stride, &offset ); m_d3dDeviceContext-IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST); // Set the vertex and pixel shader stage state. m_d3dDeviceContext-VSSetShader( vertexShader.Get(), nullptr, 0 ); m_d3dDeviceContext-PSSetShader( pixelShader.Get(), nullptr, 0 ); // Draw the cube. m_d3dDeviceContext-Draw(3,0); // Present the rendered image to the window. Because the maximum frame latency is set to 1, // the render loop will generally be throttled to the screen refresh rate, typically around // 60Hz, by sleeping the application on Present until the screen is refreshed. DX::ThrowIfFailed( m_swapChain-Present(1, 0) ); } } // This method is called before the application exits. void Uninitialize() { } private: // This method is called whenever the application window size changes. void OnWindowSizeChanged( _In_ CoreWindow^ sender, _In_ WindowSizeChangedEventArgs^ args ) { m_renderTargetView = nullptr; CreateWindowSizeDependentResources(); } // This method creates all application resources that depend on // the application window size. It is called at app initialization, // and whenever the application window size changes. void CreateWindowSizeDependentResources() { if (m_swapChain != nullptr) { // If the swap chain already exists, resize it. DX::ThrowIfFailed( m_swapChain-ResizeBuffers( 2, 0, 0, DXGI_FORMAT_R8G8B8A8_UNORM, 0 ) ); } else { // If the swap chain does not exist, create it. DXGI_SWAP_CHAIN_DESC1 swapChainDesc = {0}; swapChainDesc.Stereo = false; swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT; swapChainDesc.Scaling = DXGI_SCALING_NONE; swapChainDesc.Flags = 0; // Use automatic sizing. swapChainDesc.Width = 0; swapChainDesc.Height = 0; // This is the most common swap chain format. swapChainDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM; // Don't use multi-sampling. swapChainDesc.SampleDesc.Count = 1; swapChainDesc.SampleDesc.Quality = 0; // Use two buffers to enable flip effect. swapChainDesc.BufferCount = 2; // We recommend using this swap effect for all applications. swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_SEQUENTIAL; // Once the swap chain description is configured, it must be // created on the same adapter as the existing D3D Device. // First, retrieve the underlying DXGI Device from the D3D Device. ComPtr dxgiDevice; DX::ThrowIfFailed( m_d3dDevice.As(&dxgiDevice) ); // Ensure that DXGI does not queue more than one frame at a time. This both reduces // latency and ensures that the application will only render after each VSync, minimizing // power consumption. DX::ThrowIfFailed( dxgiDevice-SetMaximumFrameLatency(1) ); // Next, get the parent factory from the DXGI Device. ComPtr dxgiAdapter; DX::ThrowIfFailed( dxgiDevice-GetAdapter(&dxgiAdapter) ); ComPtr dxgiFactory; DX::ThrowIfFailed( dxgiAdapter-GetParent( __uuidof(IDXGIFactory2), &dxgiFactory ) ); // Finally, create the swap chain. DX::ThrowIfFailed( dxgiFactory-CreateSwapChainForImmersiveWindow( m_d3dDevice.Get(), DX::GetIUnknown(m_window), &swapChainDesc, nullptr, // allow on all displays &m_swapChain ) ); } // Once the swap chain is created, create a render target view. This will // allow Direct3D to render graphics to the window. ComPtr backBuffer; DX::ThrowIfFailed( m_swapChain-GetBuffer( 0, __uuidof(ID3D11Texture2D), &backBuffer ) ); DX::ThrowIfFailed( m_d3dDevice-CreateRenderTargetView( backBuffer.Get(), nullptr, &m_renderTargetView ) ); // After the render target view is created, specify that the viewport, // which describes what portion of the window to draw to, should cover // the entire window. D3D11_TEXTURE2D_DESC backBufferDesc = {0}; backBuffer-GetDesc(&backBufferDesc); D3D11_VIEWPORT viewport; viewport.TopLeftX = 0.0f; viewport.TopLeftY = 0.0f; viewport.Width = static_cast(backBufferDesc.Width); viewport.Height = static_cast(backBufferDesc.Height); viewport.MinDepth = D3D11_MIN_DEPTH; viewport.MaxDepth = D3D11_MAX_DEPTH; m_d3dDeviceContext-RSSetViewports(1, &viewport); } }; // This class defines how to create the custom View Provider defined above. ref class Direct3DTutorialViewProviderFactory : IViewProviderFactory { public: IViewProvider^ CreateViewProvider() { return ref new Direct3DTutorialViewProvider(); } }; [Platform::MTAThread] int main(array^) { auto viewProviderFactory = ref new Direct3DTutorialViewProviderFactory(); Windows::ApplicationModel::Core::CoreApplication::Run(viewProviderFactory); return 0; }

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  • Are all <canvas> tag dimensions in pixels?

    - by Simon Omega
    Are all tag dimensions in pixels? I am asking because I understood them to be. But my math is broken or I am just not grasping something here. I have been doing python mostly and just jumped back into Java Scripting. If I am just doing something stupid let me know. For a game I am writing, I wanted to have a blocky gradient. I have the following: HTML <canvas id="heir"></canvas> CSS @media screen { body { font-size: 12pt } /* Game Rendering Space */ canvas { width: 640px; height: 480px; border-style: solid; border-width: 1px; } } JavaScript (Shortened) function testDraw ( thecontext ) { var myblue = 255; thecontext.save(); // Save All Settings (Before this Function was called) for (var i = 0; i < 480; i = i + 10 ) { if (myblue.toString(16).length == 1) { thecontext.fillStyle = "#00000" + myblue.toString(16); } else { thecontext.fillStyle = "#0000" + myblue.toString(16); } thecontext.fillRect(0, i, 640, 10); myblue = myblue - 2; }; thecontext.restore(); // Restore Settings to Save Point (Removing Styles, etc...) } function main () { var targetcontext = document.getElementById(“main”).getContext("2d"); testDraw(targetcontext); } To me this should produce a series of 640w by 10h pixel bars. In Google Chrome and Fire Fox I get 15 bars. To me that means ( 480 / 15 ) is 32 pixel high bars. So I change the code to: function testDraw ( thecontext ) { var myblue = 255; thecontext.save(); // Save All Settings (Before this Function was called) for (var i = 0; i < 16; i++ ) { if (myblue.toString(16).length == 1) { thecontext.fillStyle = "#00000" + myblue.toString(16); } else { thecontext.fillStyle = "#0000" + myblue.toString(16); } thecontext.fillRect(0, (i * 10), 640, 10); myblue = myblue - 10; }; thecontext.restore(); // Restore Settings to Save Point (Removing Styles, etc...) } And get a true 32 pixel height result for comparison. Other than the fact that the first code snippet has shades of blue rendering in non-visible portions of the they are measuring 32 pixels. Now back to the Original Java Code... If I inspect the tag in Chrome it reports 640 x 480. If I inspect it in Fire Fox it reports 640 x 480. BUT! Fire Fox exports the original code to png at 300 x 150 (which is 15 rows of 10). Is it some how being resized to 640 x 480 by the CSS instead of being set to a true 640 x 480? Why, how, what? O_o I confused...

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  • Speeding up procedural texture generation

    - by FalconNL
    Recently I've begun working on a game that takes place in a procedurally generated solar system. After a bit of a learning curve (having neither worked with Scala, OpenGL 2 ES or Libgdx before), I have a basic tech demo going where you spin around a single procedurally textured planet: The problem I'm running into is the performance of the texture generation. A quick overview of what I'm doing: a planet is a cube that has been deformed to a sphere. To each side, a n x n (e.g. 256 x 256) texture is applied, which are bundled in one 8n x n texture that is sent to the fragment shader. The last two spaces are not used, they're only there to make sure the width is a power of 2. The texture is currently generated on the CPU, using the updated 2012 version of the simplex noise algorithm linked to in the paper 'Simplex noise demystified'. The scene I'm using to test the algorithm contains two spheres: the planet and the background. Both use a greyscale texture consisting of six octaves of 3D simplex noise, so for example if we choose 128x128 as the texture size there are 128 x 128 x 6 x 2 x 6 = about 1.2 million calls to the noise function. The closest you will get to the planet is about what's shown in the screenshot and since the game's target resolution is 1280x720 that means I'd prefer to use 512x512 textures. Combine that with the fact the actual textures will of course be more complicated than basic noise (There will be a day and night texture, blended in the fragment shader based on sunlight, and a specular mask. I need noise for continents, terrain color variation, clouds, city lights, etc.) and we're looking at something like 512 x 512 x 6 x 3 x 15 = 70 million noise calls for the planet alone. In the final game, there will be activities when traveling between planets, so a wait of 5 or 10 seconds, possibly 20, would be acceptable since I can calculate the texture in the background while traveling, though obviously the faster the better. Getting back to our test scene, performance on my PC isn't too terrible, though still too slow considering the final result is going to be about 60 times worse: 128x128 : 0.1s 256x256 : 0.4s 512x512 : 1.7s This is after I moved all performance-critical code to Java, since trying to do so in Scala was a lot worse. Running this on my phone (a Samsung Galaxy S3), however, produces a more problematic result: 128x128 : 2s 256x256 : 7s 512x512 : 29s Already far too long, and that's not even factoring in the fact that it'll be minutes instead of seconds in the final version. Clearly something needs to be done. Personally, I see a few potential avenues, though I'm not particularly keen on any of them yet: Don't precalculate the textures, but let the fragment shader calculate everything. Probably not feasible, because at one point I had the background as a fullscreen quad with a pixel shader and I got about 1 fps on my phone. Use the GPU to render the texture once, store it and use the stored texture from then on. Upside: might be faster than doing it on the CPU since the GPU is supposed to be faster at floating point calculations. Downside: effects that cannot (easily) be expressed as functions of simplex noise (e.g. gas planet vortices, moon craters, etc.) are a lot more difficult to code in GLSL than in Scala/Java. Calculate a large amount of noise textures and ship them with the application. I'd like to avoid this if at all possible. Lower the resolution. Buys me a 4x performance gain, which isn't really enough plus I lose a lot of quality. Find a faster noise algorithm. If anyone has one I'm all ears, but simplex is already supposed to be faster than perlin. Adopt a pixel art style, allowing for lower resolution textures and fewer noise octaves. While I originally envisioned the game in this style, I've come to prefer the realistic approach. I'm doing something wrong and the performance should already be one or two orders of magnitude better. If this is the case, please let me know. If anyone has any suggestions, tips, workarounds, or other comments regarding this problem I'd love to hear them.

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  • Why are my Unity procedural animations jerky?

    - by Phoenix Perry
    I'm working in Unity and getting some crazy weird motion behavior. I have a plane and I'm moving it. It's ever so slightly getting about 1 pixel bigger and smaller. It looks like the it's kind of getting squeezed sideways by a pixel. I'm moving a plane by cos and sin so it will spin on the x and z axes. If the planes are moving at Time.time, everything is fine. However, if I put in slower speed multiplier, I get an amazingly weird jerk in my animation. I get it with or without the lerp. How do I fix it? I want it to move very slowly. Is there some sort of invisible grid in unity? Some sort of minimum motion per frame? I put a visual sample of the behavior here. Here's the relevant code: public void spin() { for (int i = 0; i < numPlanes; i++ ) { GameObject g = planes[i] as GameObject; //alt method //currentRotation += speed * Time.deltaTime * 100; //rotation.eulerAngles = new Vector3(0, currentRotation, 0); //g.transform.position = rotation * rotationRadius; //sine method g.GetComponent<PlaneSetup>().pos.x = g.GetComponent<PlaneSetup>().radiusX * (Mathf.Cos((Time.time*speed) + g.GetComponent<PlaneSetup>().startAngle)); g.GetComponent<PlaneSetup>().pos.z = g.GetComponent<PlaneSetup>().radius * Mathf.Sin((Time.time*speed) + g.GetComponent<PlaneSetup>().startAngle); g.GetComponent<PlaneSetup>().pos.y = g.GetComponent<Transform>().position.y; ////offset g.GetComponent<PlaneSetup>().pos.z += 20; g.GetComponent<PlaneSetup>().posLerp.x = Mathf.Lerp(g.transform.position.x,g.GetComponent<PlaneSetup>().pos.x, .5f); g.GetComponent<PlaneSetup>().posLerp.z = Mathf.Lerp(g.transform.position.z, g.GetComponent<PlaneSetup>().pos.z, .5f); g.GetComponent<PlaneSetup>().posLerp.y = g.GetComponent<Transform>().position.y; g.transform.position = g.GetComponent<PlaneSetup>().posLerp; } Invoke("spin",0.0f); } The full code is on github. There is literally nothing else going on. I've turned off all other game objects so it's only the 40 planes with a texture2D shader. I removed it from Invoke and tried it in Update -- still happens. With a set frame rate or not, the same problem occurs. Tested it in Fixed Update. Same issue. The script on the individual plane doesn't even have an update function in it. The data on it could functionally live in a struct. I'm getting between 90 and 123 fps. Going to investigate and test further. I put this in an invoke function to see if I could get around it just occurring in update. There are no physics on these shapes. It's a straight procedural animation. Limited it to 1 plane - still happens. Thoughts? Removed the shader - still happening.

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  • Numerically stable(ish) method of getting Y-intercept of mouse position?

    - by Fraser
    I'm trying to unproject the mouse position to get the position on the X-Z plane of a ray cast from the mouse. The camera is fully controllable by the user. Right now, the algorithm I'm using is... Unproject the mouse into the camera to get the ray: Vector3 p1 = Vector3.Unproject(new Vector3(x, y, 0), 0, 0, width, height, nearPlane, farPlane, viewProj; Vector3 p2 = Vector3.Unproject(new Vector3(x, y, 1), 0, 0, width, height, nearPlane, farPlane, viewProj); Vector3 dir = p2 - p1; dir.Normalize(); Ray ray = Ray(p1, dir); Then get the Y-intercept by using algebra: float t = -ray.Position.Y / ray.Direction.Y; Vector3 p = ray.Position + t * ray.Direction; The problem is that the projected position is "jumpy". As I make small adjustments to the mouse position, the projected point moves in strange ways. For example, if I move the mouse one pixel up, it will sometimes move the projected position down, but when I move it a second pixel, the project position will jump back to the mouse's location. The projected location is always close to where it should be, but it does not smoothly follow a moving mouse. The problem intensifies as I zoom the camera out. I believe the problem is caused by numeric instability. I can make minor improvements to this by doing some computations at double precision, and possibly abusing the fact that floating point calculations are done at 80-bit precision on x86, however before I start micro-optimizing this and getting deep into how the CLR handles floating point, I was wondering if there's an algorithmic change I can do to improve this? EDIT: A little snooping around in .NET Reflector on SlimDX.dll: public static Vector3 Unproject(Vector3 vector, float x, float y, float width, float height, float minZ, float maxZ, Matrix worldViewProjection) { Vector3 coordinate = new Vector3(); Matrix result = new Matrix(); Matrix.Invert(ref worldViewProjection, out result); coordinate.X = (float) ((((vector.X - x) / ((double) width)) * 2.0) - 1.0); coordinate.Y = (float) -((((vector.Y - y) / ((double) height)) * 2.0) - 1.0); coordinate.Z = (vector.Z - minZ) / (maxZ - minZ); TransformCoordinate(ref coordinate, ref result, out coordinate); return coordinate; } // ... public static void TransformCoordinate(ref Vector3 coordinate, ref Matrix transformation, out Vector3 result) { Vector3 vector; Vector4 vector2 = new Vector4 { X = (((coordinate.Y * transformation.M21) + (coordinate.X * transformation.M11)) + (coordinate.Z * transformation.M31)) + transformation.M41, Y = (((coordinate.Y * transformation.M22) + (coordinate.X * transformation.M12)) + (coordinate.Z * transformation.M32)) + transformation.M42, Z = (((coordinate.Y * transformation.M23) + (coordinate.X * transformation.M13)) + (coordinate.Z * transformation.M33)) + transformation.M43 }; float num = (float) (1.0 / ((((transformation.M24 * coordinate.Y) + (transformation.M14 * coordinate.X)) + (coordinate.Z * transformation.M34)) + transformation.M44)); vector2.W = num; vector.X = vector2.X * num; vector.Y = vector2.Y * num; vector.Z = vector2.Z * num; result = vector; } ...which seems to be a pretty standard method of unprojecting a point from a projection matrix, however this serves to introduce another point of possible instability. Still, I'd like to stick with the SlimDX Unproject routine rather than writing my own unless it's really necessary.

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  • Modern OpenGL context failure [migrated]

    - by user209347
    OK, I managed to create an OpenGL context with wglcreatecontextattribARB with version 3.2 in my attrib struct (So I have initialized a 3.2 opengl context). It works, but the strange thing is, when I use glBindBuffer e,g. I still get unreferenced linker error, shouldn't a newer context prevent this? I'm on windows BTW, Linux doesn't have to deal with older and newer contexts (it directly supports the core of its version). The code: PIXELFORMATDESCRIPTOR pfd; HGLRC tmpRC; int iFormat; if (!(hDC = GetDC(hWnd))) { CMsgBox("Unable to create a device context. Program will now close.", "Error"); return false; } ZeroMemory(&pfd, sizeof(pfd)); pfd.nSize = sizeof(pfd); pfd.nVersion = 1; pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER; pfd.iPixelType = PFD_TYPE_RGBA; pfd.cColorBits = attribs->colorbits; pfd.cDepthBits = attribs->depthbits; pfd.iLayerType = PFD_MAIN_PLANE; if (!(iFormat = ChoosePixelFormat(hDC, &pfd))) { CMsgBox("Unable to find a suitable pixel format. Program will now close.", "Error"); return false; } if (!SetPixelFormat(hDC, iFormat, &pfd)) { CMsgBox("Unable to initialize the pixel formats. Program will now close.", "Error"); return false; } if (!(tmpRC=wglCreateContext(hDC))) { CMsgBox("Unable to create a rendering context. Program will now close.", "Error"); return false; } if (!wglMakeCurrent(hDC, tmpRC)) { CMsgBox("Unable to activate the rendering context. Program will now close.", "Error"); return false; } strncpy(vers, (char*)glGetString(GL_VERSION), 3); vers[3] = '\0'; if (sscanf(vers, "%i.%i", &glv, &glsubv) != 2) { CMsgBox("Unable to retrieve the OpenGL version. Program will now close.", "Error"); return false; } hRC = NULL; if (glv > 2) // Have OpenGL 3.+ support { if ((wglCreateContextAttribsARB = (PFNWGLCREATECONTEXTATTRIBSARBPROC)wglGetProcAddress("wglCreateContextAttribsARB"))) { int attribs[] = {WGL_CONTEXT_MAJOR_VERSION_ARB, glv, WGL_CONTEXT_MINOR_VERSION_ARB, glsubv,WGL_CONTEXT_FLAGS_ARB, 0,0}; hRC = wglCreateContextAttribsARB(hDC, 0, attribs); wglMakeCurrent(NULL, NULL); wglDeleteContext(tmpRC); if (!wglMakeCurrent(hDC, hRC)) { CMsgBox("Unable to activate the rendering context. Program will now close.", "Error"); return false; } moderncontext = true; } } if (hRC == NULL) { hRC = tmpRC; moderncontext = false; }

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  • Is the Leptonica implementation of 'Modified Median Cut' not using the median at all?

    - by TheCodeJunkie
    I'm playing around a bit with image processing and decided to read up on how color quantization worked and after a bit of reading I found the Modified Median Cut Quantization algorithm. I've been reading the code of the C implementation in Leptonica library and came across something I thought was a bit odd. Now I want to stress that I am far from an expert in this area, not am I a math-head, so I am predicting that this all comes down to me not understanding all of it and not that the implementation of the algorithm is wrong at all. The algorithm states that the vbox should be split along the lagest axis and that it should be split using the following logic The largest axis is divided by locating the bin with the median pixel (by population), selecting the longer side, and dividing in the center of that side. We could have simply put the bin with the median pixel in the shorter side, but in the early stages of subdivision, this tends to put low density clusters (that are not considered in the subdivision) in the same vbox as part of a high density cluster that will outvote it in median vbox color, even with future median-based subdivisions. The algorithm used here is particularly important in early subdivisions, and 3is useful for giving visible but low population color clusters their own vbox. This has little effect on the subdivision of high density clusters, which ultimately will have roughly equal population in their vboxes. For the sake of the argument, let's assume that we have a vbox that we are in the process of splitting and that the red axis is the largest. In the Leptonica algorithm, on line 01297, the code appears to do the following Iterate over all the possible green and blue variations of the red color For each iteration it adds to the total number of pixels (population) it's found along the red axis For each red color it sum up the population of the current red and the previous ones, thus storing an accumulated value, for each red note: when I say 'red' I mean each point along the axis that is covered by the iteration, the actual color may not be red but contains a certain amount of red So for the sake of illustration, assume we have 9 "bins" along the red axis and that they have the following populations 4 8 20 16 1 9 12 8 8 After the iteration of all red bins, the partialsum array will contain the following count for the bins mentioned above 4 12 32 48 49 58 70 78 86 And total would have a value of 86 Once that's done it's time to perform the actual median cut and for the red axis this is performed on line 01346 It iterates over bins and check they accumulated sum. And here's the part that throws me of from the description of the algorithm. It looks for the first bin that has a value that is greater than total/2 Wouldn't total/2 mean that it is looking for a bin that has a value that is greater than the average value and not the median ? The median for the above bins would be 49 The use of 43 or 49 could potentially have a huge impact on how the boxes are split, even though the algorithm then proceeds by moving to the center of the larger side of where the matched value was.. Another thing that puzzles me a bit is that the paper specified that the bin with the median value should be located, but does not mention how to proceed if there are an even number of bins.. the median would be the result of (a+b)/2 and it's not guaranteed that any of the bins contains that population count. So this is what makes me thing that there are some approximations going on that are negligible because of how the split actually takes part at the center of the larger side of the selected bin. Sorry if it got a bit long winded, but I wanted to be as thoroughas I could because it's been driving me nuts for a couple of days now ;)

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  • CGBitmapContextCreate on the iPhone/iPad

    - by toastie
    Hello, I have a method that needs to parse through a bunch of large PNG images pixel by pixel (the PNGs are 600x600 pixels each). It seems to work great on the Simulator, but on the device (iPad), i get an EXC_BAD_ACCESS in some internal memory copying function. It seems the size is the culprit because if I try it on smaller images, everything seems to work. Here's the memory related meat of method below. + (CGRect) getAlphaBoundsForUImage: (UIImage*) image { CGImageRef imageRef = [image CGImage]; NSUInteger width = CGImageGetWidth(imageRef); NSUInteger height = CGImageGetHeight(imageRef); CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); unsigned char *rawData = malloc(height * width * 4); memset(rawData,0,height * width * 4); NSUInteger bytesPerPixel = 4; NSUInteger bytesPerRow = bytesPerPixel * width; NSUInteger bitsPerComponent = 8; CGContextRef context = CGBitmapContextCreate(rawData, width, height, bitsPerComponent, bytesPerRow, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big); CGColorSpaceRelease(colorSpace); CGContextDrawImage(context, CGRectMake(0, 0, width, height), imageRef); CGContextRelease(context); /* non-memory related stuff */ free(rawData); When I run this on a bunch of images, it runs 12 times and then craps out, while on the simulator it runs no problem. Do you guys have any ideas?

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  • Interpolation and Morphing of an image in labview and/or openCV

    - by Marc
    I am working on an image manipulation problem. I have an overhead projector that projects onto a screen, and I have a camera that takes pictures of that. I can establish a 1:1 correspondence between a subset of projector coordinates and a subset of camera pixels by projecting dots on the screen and finding the centers of mass of the resulting regions on the camera. I thus have a map proj_x, proj_y <-- cam_x, cam_y for scattered point pairs My original plan was to regularize this map using the Mathscript function griddata. This would work fine in MATLAB, as follows [pgridx, pgridy] = meshgrid(allprojxpts, allprojypts) fitcx = griddata (proj_x, proj_y, cam_x, pgridx, pgridy); fitcy = griddata (proj_x, proj_y, cam_y, pgridx, pgridy); and the reverse for the camera to projector mapping Unfortunately, this code causes Labview to run out of memory on the meshgrid step (the camera is 5 megapixels, which apparently is too much for labview to handle) I then started looking through openCV, and found the cvRemap function. Unfortunately, this function takes as its starting point a regularized pixel-pixel map like the one I was trying to generate above. However, it made me hope that functions for creating such a map might be available in openCV. I couldn't find it in the openCV 1.0 API (I am stuck with 1.0 for legacy reasons), but I was hoping it's there or that someone has an easy trick. So my question is one of the following 1) How can I interpolate from scattered points to a grid in openCV; (i.e., given z = f(x,y) for scattered values of x and y, how to fill an image with f(im_x, im_y) ? 2) How can I perform an image transform that maps image 1 to image 2, given that I know a scattered mapping of points in coordinate system 1 to coordinate system 2. This could be implemented either in Labview or OpenCV. Note: I am tagging this post delaunay, because that's one method of doing a scattered interpolation, but the better tag would be "scattered interpolation"

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  • Eigenvector computation using OpenCV

    - by Andriyev
    Hi I have this matrix A, representing similarities of pixel intensities of an image. For example: Consider a 10 x 10 image. Matrix A in this case would be of dimension 100 x 100, and element A(i,j) would have a value in the range 0 to 1, representing the similarity of pixel i to j in terms of intensity. I am using OpenCV for image processing and the development environment is C on Linux. Objective is to compute the Eigenvectors of matrix A and I have used the following approach: static CvMat mat, *eigenVec, *eigenVal; static double A[100][100]={}, Ain1D[10000]={}; int cnt=0; //Converting matrix A into a one dimensional array //Reason: That is how cvMat requires it for(i = 0;i < affnDim;i++){ for(j = 0;j < affnDim;j++){ Ain1D[cnt++] = A[i][j]; } } mat = cvMat(100, 100, CV_32FC1, Ain1D); cvEigenVV(&mat, eigenVec, eigenVal, 1e-300); for(i=0;i < 100;i++){ val1 = cvmGet(eigenVal,i,0); //Fetching Eigen Value for(j=0;j < 100;j++){ matX[i][j] = cvmGet(eigenVec,i,j); //Fetching each component of Eigenvector i } } Problem: After execution I get nearly all components of all the Eigenvectors to be zero. I tried different images and also tried populating A with random values between 0 and 1, but the same result. Few of the top eigenvalues returned look like the following: 9805401476911479666115491135488.000000 -9805401476911479666115491135488.000000 -89222871725331592641813413888.000000 89222862280598626902522986496.000000 5255391142666987110400.000000 I am now thinking on the lines of using cvSVD() which performs singular value decomposition of real floating-point matrix and might yield me the eigenvectors. But before that I thought of asking it here. Is there anything absurd in my current approach? Am I using the right API i.e. cvEigenVV() for the right input matrix (my matrix A is a floating point matrix)? cheers

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  • Tiff Analyzer

    - by Kevin
    I am writing a program to convert some data, mainly a bunch of Tiff images. Some of the Tiffs seems to have a minor problem with them. They show up fine in some viewers (Irfanview, client's old system) but not in others (Client's new system, Window's picture and fax viewer). I have manually looked at the binary data and all the tags seem ok. Can anyone recommend an app that can analyze it and tell me what, if anything, is wrong with it? Also, for clarity sake, I'm only converting the data about the images which is stored seperately in a database and copying the images, I'm not editting the images myself, so I'm pretty sure I'm not messing them up. UDPATE: For anyone interested, here are the tags from a good and bad file: BAD Tag Type Length Value 256 Image Width SHORT 1 1652 257 Image Length SHORT 1 704 258 Bits Per Sample SHORT 1 1 259 Compression SHORT 1 4 262 Photometric SHORT 1 0 266 Fill Order SHORT 1 1 273 Strip Offsets LONG 1 210 (d2 Hex) 274 Orientation SHORT 1 3 277 Samples Per Pixel SHORT 1 1 278 Rows Per Strip SHORT 1 450 279 Strip Byte Counts LONG 1 7264 (1c60 Hex) 282 X Resolution RATIONAL 1 <194 200 / 1 = 200.000 283 Y Resolution RATIONAL 1 <202 200 / 1 = 200.000 284 Planar Configuration SHORT 1 1 296 Resolution Unit SHORT 1 2 Good Tag Type Length Value 254 New Subfile Type LONG 1 0 (0 Hex) 256 Image Width SHORT 1 1193 257 Image Length SHORT 1 788 258 Bits Per Sample SHORT 1 1 259 Compression SHORT 1 4 262 Photometric SHORT 1 0 266 Fill Order SHORT 1 1 270 Image Description ASCII 45 256 273 Strip Offsets LONG 1 1118 (45e Hex) 274 Orientation SHORT 1 1 277 Samples Per Pixel SHORT 1 1 278 Rows Per Strip LONG 1 788 (314 Hex) 279 Strip Byte Counts LONG 1 496 (1f0 Hex) 280 Min Sample Value SHORT 1 0 281 Max Sample Value SHORT 1 1 282 X Resolution RATIONAL 1 <301 200 / 1 = 200.000 283 Y Resolution RATIONAL 1 <309 200 / 1 = 200.000 284 Planar Configuration SHORT 1 1 293 Group 4 Options LONG 1 0 (0 Hex) 296 Resolution Unit SHORT 1 2

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  • GPGPU programming with OpenGL ES 2.0

    - by Albus Dumbledore
    I am trying to do some image processing on the GPU, e.g. median, blur, brightness, etc. The general idea is to do something like this framework from GPU Gems 1. I am able to write the GLSL fragment shader for processing the pixels as I've been trying out different things in an effect designer app. I am not sure however how I should do the other part of the task. That is, I'd like to be working on the image in image coords and then outputting the result to a texture. I am aware of the gl_FragCoords variable. As far as I understand it it goes like that: I need to set up a view (an orthographic one maybe?) and a quad in such a way so that the pixel shader would be applied once to each pixel in the image and so that it would be rendering to a texture or something. But how can I achieve that considering there's depth that may make things somewhat awkward to me... I'd be very grateful if anyone could help me with this rather simple task as I am really frustrated with myself. UPDATE It seems I'll have to use an FBO, getting one like this: glBindFramebuffer(...)

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  • deleting HBITMAP causes an access violation at runtime.

    - by Oliver
    Hi, I have the following code to take a screenshot of a window, and get the colour of a specific pixel in it: void ProcessScreenshot(HWND hwnd){ HDC WinDC; HDC CopyDC; HBITMAP hBitmap; RECT rt; GetClientRect (hwnd, &rt); WinDC = GetDC (hwnd); CopyDC = CreateCompatibleDC (WinDC); //Create a bitmap compatible with the DC hBitmap = CreateCompatibleBitmap (WinDC, rt.right - rt.left, //width rt.bottom - rt.top);//height SelectObject (CopyDC, hBitmap); BitBlt (CopyDC, //destination 0,0, rt.right - rt.left, //width rt.bottom - rt.top, //height WinDC, //source 0, 0, SRCCOPY); COLORREF col = ::GetPixel(CopyDC,145,293); // Do some stuff with the pixel colour.... delete hBitmap; ReleaseDC(hwnd, WinDC); ReleaseDC(hwnd, CopyDC); } the line 'delete hBitmap;' causes a runtime error: an access violation. I guess I can't just delete it like that? Because bitmaps take up a lot of space, if I don't get rid of it I will end up with a huge memory leak. My question is: Does releasing the DC the HBITMAP is from deal with this, or does it stick around even after I have released the DC? If the later is the case, how do I correctly get rid of the HBITMAP?

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  • QT- QImage and multi-threading problem.

    - by umanga
    Greetings all, Please refer to image at : http://i48.tinypic.com/316qb78.jpg We are developing an application to extract cell edges from MRC images from electron microscope. MRC file format stores volumetric pixel data (http://en.wikipedia.org/wiki/Voxel) and we simply use 3D char array(char***) to load and store data (gray scale values) from a MRC file. As shown in the image,there are 3 viewers to display XY,YZ and ZX planes respectively. Scrollbars on the top of the viewers use to change the image slice along an axis. Here is the steps we do when user changes the scrollbar position. 1) get the new scrollbar value.(this is the selected slice) 2) for the relavant plane (YZ,XY or ZX), generate (char* slice;) array for the selected slice by reading 3D char array (char***) 3) Create a new QImage* (Format_RGB888) and set pixel values by reading 'slice' (using img-setPixel(x,y,c);) 4) This new QImage* is painted in the paintEvent() method. We are going to execute "edge-detection" process in a seperate thread since it is an intensive process.During this process we need to draw detected curve (set of pixels) on top of above QImage*.(as a layer).This means we need to call drawPoint() methods outside the QT thread. Is it the best wayto use QImage for this case? What is the best way to execute QT drawing methods from another thread? thanks in advance,

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