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  • Memory allocation in Linux

    - by Goofy
    Hello! I have a multi threaded application where I allocate buffers with data, which then wait in queues to be send via sockets. All buffers are reproducible because I use only buffers of fixed size in whole program (1024, 2048, 2080 and 5248 bytes). I noticed, that my program usually use up to 10 buffers of each length type at the same moment. So far I always manually allocate new buffer and then free it (using malloc() and free ()) where it's not needed any more. I started wondering if Linux is enough smart to cache this memory for me, so next time I allocate new buffer system only quickly receive a buffer I have already used before and not perform heavy operation of allocating new memory block?

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  • Can I use the emacs keyboard macro counter as a command prefix?

    - by Sean M
    I'm working on a project in emacs where I'd like to use a keyboard macro that changes slightly with each iteration. When I saw the keyboard macro counter in the manual, that looked like exactly what I needed - but as far as I can tell, that inserts an incrementing number into the current buffer. I want to use an incrementing number as a prefix to another command. For example, instead of inserting 3 into the buffer on the third execution of the macro, I'd like to be able to execute C-u 3 M-x my-command, followed by C-u 4 M-x my-command on the next iteration. Is there way to create a keyboard macro that does this? My specific task is "zipping" two blocks of text in the same buffer together, but even if there's an alternative way to do that specific thing, it'd be good to know the answer to the general question.

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  • Java ThreadPool for multiple identical tasks

    - by tdimmig
    I have 1 thread who sole job is to grab DatagramPackets off of a socket and stick them in a buffer. Another thread works out of that buffer, processing the DatagramPackets. I'd like to have a pool of threads working out of that buffer. I had thought to use a fixed thread pool to do this. To do so, do I need to create the pool, then submit enough runnables for execution to fill it up? I had hoped for a way to say "this is the thread/runnable that I want you to execute, this is how many I want running, GO!". Is there such a method of doing this? Is something other than a fixed thread pool better suited?

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  • How can I get the JSON array data from nsstring or byte in xcode 4.2?

    - by user1471568
    I'm trying to get values from nsdata class and doesn't work. here is my JSON data. { "count": 3, "item": [{ "id": "1", "latitude": "37.556811", "longitude": "126.922015", "imgUrl": "http://175.211.62.15/sample_res/1.jpg", "found": false }, { "id": "3", "latitude": "37.556203", "longitude": "126.922629", "imgUrl": "http://175.211.62.15/sample_res/3.jpg", "found": false }, { "id": "2", "latitude": "37.556985", "longitude": "126.92286", "imgUrl": "http://175.211.62.15/sample_res/2.jpg", "found": false }] } and here is my code -(NSDictionary *)getDataFromItemList { NSData *dataBody = [[NSData alloc] initWithBytes:buffer length:sizeof(buffer)]; NSDictionary *iTem = [[NSDictionary alloc]init]; iTem = [NSJSONSerialization JSONObjectWithData:dataBody options:NSJSONReadingMutableContainers error:nil]; NSLog(@"id = %@",[iTem objectForKey:@"id"]); //for Test output = [[NSString alloc] initWithBytes:buffer length:rangeHeader.length encoding:NSUTF8StringEncoding]; NSLog(@"%@",output); return iTem; } how can I access every value in the JSON? Please help me.

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  • Using ftp in C# to send a file

    - by pm_2
    I'm trying to send a file using ftp. I have the following code: string server = "x.x.x.x"; // Just the IP Address FileStream stream = File.OpenRead(filename); byte[] buffer = new byte[stream.Length]; WebRequest request = WebRequest.Create("ftp://" + server); request.Method = WebRequestMethods.Ftp.UploadFile; request.Credentials = new NetworkCredential(username, password); Stream reqStream = request.GetRequestStream(); // This line fails reqStream.Write(buffer, 0, buffer.Length); reqStream.Close(); But when I run it, I get the following error: The requested URI is invalid for this FTP command. Please can anyone tell me why? Am I using this incorrectly?

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  • DirectX11 Swap Chain RGBA vs BGRA Format

    - by Nathan
    I was wondering if anyone could elaborate any further on something that's been bugging me. In DirectX9 the main supported back buffer formats were D3DFMT_X8R8B8G8 and D3DFMT_A8R8G8B8 (Both being BGRA in layout). http://msdn.microsoft.com/en-us/library/windows/desktop/bb174314(v=vs.85).aspx With the initial version of DirectX10 their was no support for BGRA and all the textbooks and online tutorials recommend DXGI_FORMAT_R8G8B8A8_UNORM (being RGBA in layout). Now with DirectX11 BGRA is supported again and it seems as if microsoft recommends using a BGRA format as the back buffer format. http://msdn.microsoft.com/en-us/library/windows/apps/hh465096.aspx Are there any suggestions or are there performance implications of using one or the other? (I assume not as obviously by specifying the format of the underlying resource the runtime will handle what bits your passing through and than infer how to utilise them based on the format.)

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  • DirectX11 Swap Chain Format

    - by Nathan
    I was wondering if anyone could elaborate any further on something thats been bugging be me. In DirectX9 the main supported back buffer formats were D3DFMT_X8R8B8G8 and D3DFMT_A8R8G8B8 (Both being BGRA in layout). http://msdn.microsoft.com/en-us/library/windows/desktop/bb174314(v=vs.85).aspx With the initial version of DirectX10 their was no support for BGRA and all the textbooks and online tutorials recommend DXGI_FORMAT_R8G8B8A8_UNORM (being RGBA in layout). Now with DirectX11 BGRA is supported again and it seems as if microsoft recommends using a BGRA format as the back buffer format. http://msdn.microsoft.com/en-us/library/windows/apps/hh465096.aspx Is their any suggestions or are their performance implications of using one or the other. (I assume not as obviously by specifying the format of the underlying resource the runtime will handle what bits your passing through and than infer how to utilise them based on the format). Any feedback is appreciated.

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  • OpenGL's matrix stack vs Hand multiplying

    - by deft_code
    Which is more efficient using OpenGL's transformation stack or applying the transformations by hand. I've often heard that you should minimize the number of state transitions in your graphics pipeline. Pushing and popping translation matrices seem like a big change. However, I wonder if the graphics card might be able to more than make up for pipeline hiccup by using its parallel execution hardware to bulk multiply the vertices. My specific case. I have font rendered to a sprite sheet. The coordinates of each character or a string are calculated and added to a vertex buffer. Now I need to move that string. Would it be better to iterate through the vertex buffer and adjust each of the vertices by hand or temporarily push a new translation matrix?

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  • Get the onended event for an AudioBuffer in HTML5/Chrome

    - by Matthew James Davis
    So I am playing audio file in Chrome and I want to detect when playing has ended so I can delete references to it. Here is my code var source = context.createBufferSource(); source.buffer = sound.buffer; source.loop = sound.loop; source.onended = function() { delete playingSounds[soundName]; } source.connect(mainNode); source.start(0, sound.start, sound.length); however, the event handler doesn't fire. Is this not yet supported as described by the W3 specification? Or am I doing something wrong?

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  • Why does setting a geometry shader cause my sprites to vanish?

    - by ChaosDev
    My application has multiple screens with different tasks. Once I set a geometry shader to the device context for my custom terrain, it works and I get the desired results. But then when I get back to the main menu, all sprites and text disappear. These sprites don't dissappear when I use pixel and vertex shaders. The sprites are being drawn through D3D11, of course, with specified view and projection matrices as well an input layout, vertex, and pixel shader. I'm trying DeviceContext->ClearState() but it does not help. Any ideas? void gGeometry::DrawIndexedWithCustomEffect(gVertexShader*vs,gPixelShader* ps,gGeometryShader* gs=nullptr) { unsigned int offset = 0; auto context = mp_D3D->mp_Context; //set topology context->IASetPrimitiveTopology(m_Topology); //set input layout context->IASetInputLayout(mp_inputLayout); //set vertex and index buffers context->IASetVertexBuffers(0,1,&mp_VertexBuffer->mp_Buffer,&m_VertexStride,&offset); context->IASetIndexBuffer(mp_IndexBuffer->mp_Buffer,mp_IndexBuffer->m_DXGIFormat,0); //send constant buffers to shaders context->VSSetConstantBuffers(0,vs->m_CBufferCount,vs->m_CRawBuffers.data()); context->PSSetConstantBuffers(0,ps->m_CBufferCount,ps->m_CRawBuffers.data()); if(gs!=nullptr) { context->GSSetConstantBuffers(0,gs->m_CBufferCount,gs->m_CRawBuffers.data()); context->GSSetShader(gs->mp_D3DGeomShader,0,0);//after this call all sprites disappear } //set shaders context->VSSetShader( vs->mp_D3DVertexShader, 0, 0 ); context->PSSetShader( ps->mp_D3DPixelShader, 0, 0 ); //draw context->DrawIndexed(m_indexCount,0,0); } //sprites void gSpriteDrawer::Draw(gTexture2D* texture,const RECT& dest,const RECT& source, const Matrix& spriteMatrix,const float& rotation,Vector2d& position,const Vector2d& origin,const Color& color) { VertexPositionColorTexture* verticesPtr; D3D11_MAPPED_SUBRESOURCE mappedResource; unsigned int TriangleVertexStride = sizeof(VertexPositionColorTexture); unsigned int offset = 0; float halfWidth = ( float )dest.right / 2.0f; float halfHeight = ( float )dest.bottom / 2.0f; float z = 0.1f; int w = texture->Width(); int h = texture->Height(); float tu = (float)source.right/(w); float tv = (float)source.bottom/(h); float hu = (float)source.left/(w); float hv = (float)source.top/(h); Vector2d t0 = Vector2d( hu+tu, hv); Vector2d t1 = Vector2d( hu+tu, hv+tv); Vector2d t2 = Vector2d( hu, hv+tv); Vector2d t3 = Vector2d( hu, hv+tv); Vector2d t4 = Vector2d( hu, hv); Vector2d t5 = Vector2d( hu+tu, hv); float ex=(dest.right/2)+(origin.x); float ey=(dest.bottom/2)+(origin.y); Vector4d v4Color = Vector4d(color.r,color.g,color.b,color.a); VertexPositionColorTexture vertices[] = { { Vector3d( dest.right-ex, -ey, z),v4Color, t0}, { Vector3d( dest.right-ex, dest.bottom-ey , z),v4Color, t1}, { Vector3d( -ex, dest.bottom-ey , z),v4Color, t2}, { Vector3d( -ex, dest.bottom-ey , z),v4Color, t3}, { Vector3d( -ex, -ey , z),v4Color, t4}, { Vector3d( dest.right-ex, -ey , z),v4Color, t5}, }; auto mp_context = mp_D3D->mp_Context; // Lock the vertex buffer so it can be written to. mp_context->Map(mp_vertexBuffer, 0, D3D11_MAP_WRITE_DISCARD, 0, &mappedResource); // Get a pointer to the data in the vertex buffer. verticesPtr = (VertexPositionColorTexture*)mappedResource.pData; // Copy the data into the vertex buffer. memcpy(verticesPtr, (void*)vertices, (sizeof(VertexPositionColorTexture) * 6)); // Unlock the vertex buffer. mp_context->Unmap(mp_vertexBuffer, 0); //set vertex shader mp_context->IASetVertexBuffers( 0, 1, &mp_vertexBuffer, &TriangleVertexStride, &offset); //set texture mp_context->PSSetShaderResources( 0, 1, &texture->mp_SRV); //set matrix to shader mp_context->UpdateSubresource(mp_matrixBuffer, 0, 0, &spriteMatrix, 0, 0 ); mp_context->VSSetConstantBuffers( 0, 1, &mp_matrixBuffer); //draw sprite mp_context->Draw( 6, 0 ); }

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  • Slow boot on Ubuntu 12.04

    - by Hailwood
    My Ubuntu is booting really slow (Windows is booting faster...). I am using Ubuntu a Dell Inspiron 1545 Pentium(R) Dual-Core CPU T4300 @ 2.10GHz, 4GB Ram, 500GB HDD running Ubuntu 12.04 with gnome-shell 3.4.1. After running dmesg the culprit seems to be this section, in particular the last three lines: [26.557659] ADDRCONF(NETDEV_UP): eth0: link is not ready [26.565414] ADDRCONF(NETDEV_UP): eth0: link is not ready [27.355355] Console: switching to colour frame buffer device 170x48 [27.362346] fb0: radeondrmfb frame buffer device [27.362347] drm: registered panic notifier [27.362357] [drm] Initialized radeon 2.12.0 20080528 for 0000:01:00.0 on minor 0 [27.617435] init: udev-fallback-graphics main process (1049) terminated with status 1 [30.064481] init: plymouth-stop pre-start process (1500) terminated with status 1 [51.708241] CE: hpet increased min_delta_ns to 20113 nsec [59.448029] eth2: no IPv6 routers present But I have no idea how to start debugging this. sudo lshw -C video $ sudo lshw -C video *-display description: VGA compatible controller product: RV710 [Mobility Radeon HD 4300 Series] vendor: Hynix Semiconductor (Hyundai Electronics) physical id: 0 bus info: pci@0000:01:00.0 version: 00 width: 32 bits clock: 33MHz capabilities: pm pciexpress msi vga_controller bus_master cap_list rom configuration: driver=fglrx_pci latency=0 resources: irq:48 memory:e0000000-efffffff ioport:de00(size=256) memory:f6df0000-f6dfffff memory:f6d00000-f6d1ffff After loading the propriety driver my new dmesg log is below (starting from the first major time gap): [2.983741] EXT4-fs (sda6): mounted filesystem with ordered data mode. Opts: (null) [25.094327] ADDRCONF(NETDEV_UP): eth0: link is not ready [25.119737] udevd[520]: starting version 175 [25.167086] lp: driver loaded but no devices found [25.215341] fglrx: module license 'Proprietary. (C) 2002 - ATI Technologies, Starnberg, GERMANY' taints kernel. [25.215345] Disabling lock debugging due to kernel taint [25.231924] wmi: Mapper loaded [25.318414] lib80211: common routines for IEEE802.11 drivers [25.318418] lib80211_crypt: registered algorithm 'NULL' [25.331631] [fglrx] Maximum main memory to use for locked dma buffers: 3789 MBytes. [25.332095] [fglrx] vendor: 1002 device: 9552 count: 1 [25.334206] [fglrx] ioport: bar 1, base 0xde00, size: 0x100 [25.334229] pci 0000:01:00.0: PCI INT A -> GSI 16 (level, low) -> IRQ 16 [25.334235] pci 0000:01:00.0: setting latency timer to 64 [25.337109] [fglrx] Kernel PAT support is enabled [25.337140] [fglrx] module loaded - fglrx 8.96.4 [Mar 12 2012] with 1 minors [25.342803] Adding 4189180k swap on /dev/sda7. Priority:-1 extents:1 across:4189180k [25.364031] type=1400 audit(1338241723.027:2): apparmor="STATUS" operation="profile_load" name="/sbin/dhclient" pid=606 comm="apparmor_parser" [25.364491] type=1400 audit(1338241723.031:3): apparmor="STATUS" operation="profile_load" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=606 comm="apparmor_parser" [25.364760] type=1400 audit(1338241723.031:4): apparmor="STATUS" operation="profile_load" name="/usr/lib/connman/scripts/dhclient-script" pid=606 comm="apparmor_parser" [25.394328] wl 0000:0c:00.0: PCI INT A -> GSI 17 (level, low) -> IRQ 17 [25.394343] wl 0000:0c:00.0: setting latency timer to 64 [25.415531] acpi device:36: registered as cooling_device2 [25.416688] input: Video Bus as /devices/LNXSYSTM:00/device:00/PNP0A03:00/device:34/LNXVIDEO:00/input/input6 [25.416795] ACPI: Video Device [VID] (multi-head: yes rom: no post: no) [25.416865] [Firmware Bug]: Duplicate ACPI video bus devices for the same VGA controller, please try module parameter "video.allow_duplicates=1"if the current driver doesn't work. [25.425133] lib80211_crypt: registered algorithm 'TKIP' [25.448058] snd_hda_intel 0000:00:1b.0: PCI INT A -> GSI 21 (level, low) -> IRQ 21 [25.448321] snd_hda_intel 0000:00:1b.0: irq 47 for MSI/MSI-X [25.448353] snd_hda_intel 0000:00:1b.0: setting latency timer to 64 [25.738867] eth1: Broadcom BCM4315 802.11 Hybrid Wireless Controller 5.100.82.38 [25.761213] input: HDA Intel Mic as /devices/pci0000:00/0000:00:1b.0/sound/card0/input7 [25.761406] input: HDA Intel Headphone as /devices/pci0000:00/0000:00:1b.0/sound/card0/input8 [25.783432] dcdbas dcdbas: Dell Systems Management Base Driver (version 5.6.0-3.2) [25.908318] EXT4-fs (sda6): re-mounted. Opts: errors=remount-ro [25.928155] input: Dell WMI hotkeys as /devices/virtual/input/input9 [25.960561] udevd[543]: renamed network interface eth1 to eth2 [26.285688] init: failsafe main process (835) killed by TERM signal [26.396426] input: PS/2 Mouse as /devices/platform/i8042/serio2/input/input10 [26.423108] input: AlpsPS/2 ALPS GlidePoint as /devices/platform/i8042/serio2/input/input11 [26.511297] Bluetooth: Core ver 2.16 [26.511383] NET: Registered protocol family 31 [26.511385] Bluetooth: HCI device and connection manager initialized [26.511388] Bluetooth: HCI socket layer initialized [26.511391] Bluetooth: L2CAP socket layer initialized [26.512079] Bluetooth: SCO socket layer initialized [26.530164] Bluetooth: BNEP (Ethernet Emulation) ver 1.3 [26.530168] Bluetooth: BNEP filters: protocol multicast [26.553893] type=1400 audit(1338241724.219:5): apparmor="STATUS" operation="profile_replace" name="/sbin/dhclient" pid=928 comm="apparmor_parser" [26.554860] Bluetooth: RFCOMM TTY layer initialized [26.554866] Bluetooth: RFCOMM socket layer initialized [26.554868] Bluetooth: RFCOMM ver 1.11 [26.557910] type=1400 audit(1338241724.223:6): apparmor="STATUS" operation="profile_load" name="/usr/lib/lightdm/lightdm/lightdm-guest-session-wrapper" pid=927 comm="apparmor_parser" [26.559166] type=1400 audit(1338241724.223:7): apparmor="STATUS" operation="profile_replace" name="/usr/lib/NetworkManager/nm-dhcp-client.action" pid=928 comm="apparmor_parser" [26.559574] type=1400 audit(1338241724.223:8): apparmor="STATUS" operation="profile_replace" name="/usr/lib/connman/scripts/dhclient-script" pid=928 comm="apparmor_parser" [26.575519] type=1400 audit(1338241724.239:9): apparmor="STATUS" operation="profile_load" name="/usr/lib/telepathy/mission-control-5" pid=931 comm="apparmor_parser" [26.581100] type=1400 audit(1338241724.247:10): apparmor="STATUS" operation="profile_load" name="/usr/lib/telepathy/telepathy-*" pid=931 comm="apparmor_parser" [26.582794] type=1400 audit(1338241724.247:11): apparmor="STATUS" operation="profile_load" name="/usr/bin/evince" pid=929 comm="apparmor_parser" [26.605672] ppdev: user-space parallel port driver [27.592475] sky2 0000:09:00.0: eth0: enabling interface [27.604329] ADDRCONF(NETDEV_UP): eth0: link is not ready [27.606962] ADDRCONF(NETDEV_UP): eth0: link is not ready [27.852509] vesafb: mode is 1024x768x32, linelength=4096, pages=0 [27.852513] vesafb: scrolling: redraw [27.852515] vesafb: Truecolor: size=0:8:8:8, shift=0:16:8:0 [27.852523] mtrr: type mismatch for e0000000,400000 old: write-back new: write-combining [27.852527] mtrr: type mismatch for e0000000,200000 old: write-back new: write-combining [27.852531] mtrr: type mismatch for e0000000,100000 old: write-back new: write-combining [27.852534] mtrr: type mismatch for e0000000,80000 old: write-back new: write-combining [27.852538] mtrr: type mismatch for e0000000,40000 old: write-back new: write-combining [27.852541] mtrr: type mismatch for e0000000,20000 old: write-back new: write-combining [27.852544] mtrr: type mismatch for e0000000,10000 old: write-back new: write-combining [27.852548] mtrr: type mismatch for e0000000,8000 old: write-back new: write-combining [27.852551] mtrr: type mismatch for e0000000,4000 old: write-back new: write-combining [27.852554] mtrr: type mismatch for e0000000,2000 old: write-back new: write-combining [27.852558] mtrr: type mismatch for e0000000,1000 old: write-back new: write-combining [27.853154] vesafb: framebuffer at 0xe0000000, mapped to 0xffffc90005580000, using 3072k, total 3072k [27.853405] Console: switching to colour frame buffer device 128x48 [27.853426] fb0: VESA VGA frame buffer device [28.539800] fglrx_pci 0000:01:00.0: irq 48 for MSI/MSI-X [28.540552] [fglrx] Firegl kernel thread PID: 1168 [28.540679] [fglrx] Firegl kernel thread PID: 1169 [28.540789] [fglrx] Firegl kernel thread PID: 1170 [28.540932] [fglrx] IRQ 48 Enabled [29.845620] [fglrx] Gart USWC size:1236 M. [29.845624] [fglrx] Gart cacheable size:489 M. [29.845629] [fglrx] Reserved FB block: Shared offset:0, size:1000000 [29.845632] [fglrx] Reserved FB block: Unshared offset:fc21000, size:3df000 [29.845635] [fglrx] Reserved FB block: Unshared offset:1fffb000, size:5000 [59.700023] eth2: no IPv6 routers present

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  • Getting started with Oracle Database In-Memory Part III - Querying The IM Column Store

    - by Maria Colgan
    In my previous blog posts, I described how to install, enable, and populate the In-Memory column store (IM column store). This weeks post focuses on how data is accessed within the IM column store. Let’s take a simple query “What is the most expensive air-mail order we have received to date?” SELECT Max(lo_ordtotalprice) most_expensive_order FROM lineorderWHERE  lo_shipmode = 5; The LINEORDER table has been populated into the IM column store and since we have no alternative access paths (indexes or views) the execution plan for this query is a full table scan of the LINEORDER table. You will notice that the execution plan has a new set of keywords “IN MEMORY" in the access method description in the Operation column. These keywords indicate that the LINEORDER table has been marked for INMEMORY and we may use the IM column store in this query. What do I mean by “may use”? There are a small number of cases were we won’t use the IM column store even though the object has been marked INMEMORY. This is similar to how the keyword STORAGE is used on Exadata environments. You can confirm that the IM column store was actually used by examining the session level statistics, but more on that later. For now let's focus on how the data is accessed in the IM column store and why it’s faster to access the data in the new column format, for analytical queries, rather than the buffer cache. There are four main reasons why accessing the data in the IM column store is more efficient. 1. Access only the column data needed The IM column store only has to scan two columns – lo_shipmode and lo_ordtotalprice – to execute this query while the traditional row store or buffer cache has to scan all of the columns in each row of the LINEORDER table until it reaches both the lo_shipmode and the lo_ordtotalprice column. 2. Scan and filter data in it's compressed format When data is populated into the IM column it is automatically compressed using a new set of compression algorithms that allow WHERE clause predicates to be applied against the compressed formats. This means the volume of data scanned in the IM column store for our query will be far less than the same query in the buffer cache where it will scan the data in its uncompressed form, which could be 20X larger. 3. Prune out any unnecessary data within each column The fastest read you can execute is the read you don’t do. In the IM column store a further reduction in the amount of data accessed is possible due to the In-Memory Storage Indexes(IM storage indexes) that are automatically created and maintained on each of the columns in the IM column store. IM storage indexes allow data pruning to occur based on the filter predicates supplied in a SQL statement. An IM storage index keeps track of minimum and maximum values for each column in each of the In-Memory Compression Unit (IMCU). In our query the WHERE clause predicate is on the lo_shipmode column. The IM storage index on the lo_shipdate column is examined to determine if our specified column value 5 exist in any IMCU by comparing the value 5 to the minimum and maximum values maintained in the Storage Index. If the value 5 is outside the minimum and maximum range for an IMCU, the scan of that IMCU is avoided. For the IMCUs where the value 5 does fall within the min, max range, an additional level of data pruning is possible via the metadata dictionary created when dictionary-based compression is used on IMCU. The dictionary contains a list of the unique column values within the IMCU. Since we have an equality predicate we can easily determine if 5 is one of the distinct column values or not. The combination of the IM storage index and dictionary based pruning, enables us to only scan the necessary IMCUs. 4. Use SIMD to apply filter predicates For the IMCU that need to be scanned Oracle takes advantage of SIMD vector processing (Single Instruction processing Multiple Data values). Instead of evaluating each entry in the column one at a time, SIMD vector processing allows a set of column values to be evaluated together in a single CPU instruction. The column format used in the IM column store has been specifically designed to maximize the number of column entries that can be loaded into the vector registers on the CPU and evaluated in a single CPU instruction. SIMD vector processing enables the Oracle Database In-Memory to scan billion of rows per second per core versus the millions of rows per second per core scan rate that can be achieved in the buffer cache. I mentioned earlier in this post that in order to confirm the IM column store was used; we need to examine the session level statistics. You can monitor the session level statistics by querying the performance views v$mystat and v$statname. All of the statistics related to the In-Memory Column Store begin with IM. You can see the full list of these statistics by typing: display_name format a30 SELECT display_name FROM v$statname WHERE  display_name LIKE 'IM%'; If we check the session statistics after we execute our query the results would be as follow; SELECT Max(lo_ordtotalprice) most_expensive_order FROM lineorderWHERE lo_shipmode = 5; SELECT display_name FROM v$statname WHERE  display_name IN ('IM scan CUs columns accessed',                        'IM scan segments minmax eligible',                        'IM scan CUs pruned'); As you can see, only 2 IMCUs were accessed during the scan as the majority of the IMCUs (44) in the LINEORDER table were pruned out thanks to the storage index on the lo_shipmode column. In next weeks post I will describe how you can control which queries use the IM column store and which don't. +Maria Colgan

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  • problem with loading in .FBX meshes in DirectX 10

    - by N0xus
    I'm trying to load in meshes into DirectX 10. I've created a bunch of classes that handle it and allow me to call in a mesh with only a single line of code in my main game class. How ever, when I run the program this is what renders: In the debug output window the following errors keep appearing: D3D10: ERROR: ID3D10Device::DrawIndexed: Input Assembler - Vertex Shader linkage error: Signatures between stages are incompatible. The reason is that Semantic 'TEXCOORD' is defined for mismatched hardware registers between the output stage and input stage. [ EXECUTION ERROR #343: DEVICE_SHADER_LINKAGE_REGISTERINDEX ] D3D10: ERROR: ID3D10Device::DrawIndexed: Input Assembler - Vertex Shader linkage error: Signatures between stages are incompatible. The reason is that the input stage requires Semantic/Index (POSITION,0) as input, but it is not provided by the output stage. [ EXECUTION ERROR #342: DEVICE_SHADER_LINKAGE_SEMANTICNAME_NOT_FOUND ] The thing is, I've no idea how to fix this. The code I'm using does work and I've simply brought all of that code into a new project of mine. There are no build errors and this only appears when the game is running The .fx file is as follows: float4x4 matWorld; float4x4 matView; float4x4 matProjection; struct VS_INPUT { float4 Pos:POSITION; float2 TexCoord:TEXCOORD; }; struct PS_INPUT { float4 Pos:SV_POSITION; float2 TexCoord:TEXCOORD; }; Texture2D diffuseTexture; SamplerState diffuseSampler { Filter = MIN_MAG_MIP_POINT; AddressU = WRAP; AddressV = WRAP; }; // // Vertex Shader // PS_INPUT VS( VS_INPUT input ) { PS_INPUT output=(PS_INPUT)0; float4x4 viewProjection=mul(matView,matProjection); float4x4 worldViewProjection=mul(matWorld,viewProjection); output.Pos=mul(input.Pos,worldViewProjection); output.TexCoord=input.TexCoord; return output; } // // Pixel Shader // float4 PS(PS_INPUT input ) : SV_Target { return diffuseTexture.Sample(diffuseSampler,input.TexCoord); //return float4(1.0f,1.0f,1.0f,1.0f); } RasterizerState NoCulling { FILLMODE=SOLID; CULLMODE=NONE; }; technique10 Render { pass P0 { SetVertexShader( CompileShader( vs_4_0, VS() ) ); SetGeometryShader( NULL ); SetPixelShader( CompileShader( ps_4_0, PS() ) ); SetRasterizerState(NoCulling); } } In my game, the .fx file and model are called and set as follows: Loading in shader file //Set the shader flags - BMD DWORD dwShaderFlags = D3D10_SHADER_ENABLE_STRICTNESS; #if defined( DEBUG ) || defined( _DEBUG ) dwShaderFlags |= D3D10_SHADER_DEBUG; #endif ID3D10Blob * pErrorBuffer=NULL; if( FAILED( D3DX10CreateEffectFromFile( TEXT("TransformedTexture.fx" ), NULL, NULL, "fx_4_0", dwShaderFlags, 0, md3dDevice, NULL, NULL, &m_pEffect, &pErrorBuffer, NULL ) ) ) { char * pErrorStr = ( char* )pErrorBuffer->GetBufferPointer(); //If the creation of the Effect fails then a message box will be shown MessageBoxA( NULL, pErrorStr, "Error", MB_OK ); return false; } //Get the technique called Render from the effect, we need this for rendering later on m_pTechnique=m_pEffect->GetTechniqueByName("Render"); //Number of elements in the layout UINT numElements = TexturedLitVertex::layoutSize; //Get the Pass description, we need this to bind the vertex to the pipeline D3D10_PASS_DESC PassDesc; m_pTechnique->GetPassByIndex( 0 )->GetDesc( &PassDesc ); //Create Input layout to describe the incoming buffer to the input assembler if (FAILED(md3dDevice->CreateInputLayout( TexturedLitVertex::layout, numElements,PassDesc.pIAInputSignature, PassDesc.IAInputSignatureSize, &m_pVertexLayout ) ) ) { return false; } model loading: m_pTestRenderable=new CRenderable(); //m_pTestRenderable->create<TexturedVertex>(md3dDevice,8,6,vertices,indices); m_pModelLoader = new CModelLoader(); m_pTestRenderable = m_pModelLoader->loadModelFromFile( md3dDevice,"armoredrecon.fbx" ); m_pGameObjectTest = new CGameObject(); m_pGameObjectTest->setRenderable( m_pTestRenderable ); // Set primitive topology, how are we going to interpet the vertices in the vertex buffer md3dDevice->IASetPrimitiveTopology( D3D10_PRIMITIVE_TOPOLOGY_TRIANGLELIST ); if ( FAILED( D3DX10CreateShaderResourceViewFromFile( md3dDevice, TEXT( "armoredrecon_diff.png" ), NULL, NULL, &m_pTextureShaderResource, NULL ) ) ) { MessageBox( NULL, TEXT( "Can't load Texture" ), TEXT( "Error" ), MB_OK ); return false; } m_pDiffuseTextureVariable = m_pEffect->GetVariableByName( "diffuseTexture" )->AsShaderResource(); m_pDiffuseTextureVariable->SetResource( m_pTextureShaderResource ); Finally, the draw function code: //All drawing will occur between the clear and present m_pViewMatrixVariable->SetMatrix( ( float* )m_matView ); m_pWorldMatrixVariable->SetMatrix( ( float* )m_pGameObjectTest->getWorld() ); //Get the stride(size) of the a vertex, we need this to tell the pipeline the size of one vertex UINT stride = m_pTestRenderable->getStride(); //The offset from start of the buffer to where our vertices are located UINT offset = m_pTestRenderable->getOffset(); ID3D10Buffer * pVB=m_pTestRenderable->getVB(); //Bind the vertex buffer to input assembler stage - md3dDevice->IASetVertexBuffers( 0, 1, &pVB, &stride, &offset ); md3dDevice->IASetIndexBuffer( m_pTestRenderable->getIB(), DXGI_FORMAT_R32_UINT, 0 ); //Get the Description of the technique, we need this in order to loop through each pass in the technique D3D10_TECHNIQUE_DESC techDesc; m_pTechnique->GetDesc( &techDesc ); //Loop through the passes in the technique for( UINT p = 0; p < techDesc.Passes; ++p ) { //Get a pass at current index and apply it m_pTechnique->GetPassByIndex( p )->Apply( 0 ); //Draw call md3dDevice->DrawIndexed(m_pTestRenderable->getNumOfIndices(),0,0); //m_pD3D10Device->Draw(m_pTestRenderable->getNumOfVerts(),0); } Is there anything I've clearly done wrong or are missing? Spent 2 weeks trying to workout what on earth I've done wrong to no avail. Any insight a fresh pair eyes could give on this would be great.

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  • InnoDB Compression Improvements in MySQL 5.6

    - by Inaam Rana
    MySQL 5.6 comes with significant improvements for the compression support inside InnoDB. The enhancements that we'll talk about in this piece are also a good example of community contributions. The work on these was conceived, implemented and contributed by the engineers at Facebook. Before we plunge into the details let us familiarize ourselves with some of the key concepts surrounding InnoDB compression. In InnoDB compressed pages are fixed size. Supported sizes are 1, 2, 4, 8 and 16K. The compressed page size is specified at table creation time. InnoDB uses zlib for compression. InnoDB buffer pool will attempt to cache compressed pages like normal pages. However, whenever a page is actively used by a transaction, we'll always have the uncompressed version of the page as well i.e.: we can have a page in the buffer pool in compressed only form or in a state where we have both the compressed page and uncompressed version but we'll never have a page in uncompressed only form. On-disk we'll always only have the compressed page. When both compressed and uncompressed images are present in the buffer pool they are always kept in sync i.e.: changes are applied to both atomically. Recompression happens when changes are made to the compressed data. In order to minimize recompressions InnoDB maintains a modification log within a compressed page. This is the extra space available in the page after compression and it is used to log modifications to the compressed data thus avoiding recompressions. DELETE (and ROLLBACK of DELETE) and purge can be performed without recompressing the page. This is because the delete-mark bit and the system fields DB_TRX_ID and DB_ROLL_PTR are stored in uncompressed format on the compressed page. A record can be purged by shuffling entries in the compressed page directory. This can also be useful for updates of indexed columns, because UPDATE of a key is mapped to INSERT+DELETE+purge. A compression failure happens when we attempt to recompress a page and it does not fit in the fixed size. In such case, we first try to reorganize the page and attempt to recompress and if that fails as well then we split the page into two and recompress both pages. Now lets talk about the three major improvements that we made in MySQL 5.6.Logging of Compressed Page Images:InnoDB used to log entire compressed data on the page to the redo logs when recompression happens. This was an extra safety measure to guard against the rare case where an attempt is made to do recovery using a different zlib version from the one that was used before the crash. Because recovery is a page level operation in InnoDB we have to be sure that all recompress attempts must succeed without causing a btree page split. However, writing entire compressed data images to the redo log files not only makes the operation heavy duty but can also adversely affect flushing activity. This happens because redo space is used in a circular fashion and when we generate much more than normal redo we fill up the space much more quickly and in order to reuse the redo space we have to flush the corresponding dirty pages from the buffer pool.Starting with MySQL 5.6 a new global configuration parameter innodb_log_compressed_pages. The default value is true which is same as the current behavior. If you are sure that you are not going to attempt to recover from a crash using a different version of zlib then you should set this parameter to false. This is a dynamic parameter.Compression Level:You can now set the compression level that zlib should choose to compress the data. The global parameter is innodb_compression_level - the default value is 6 (the zlib default) and allowed values are 1 to 9. Again the parameter is dynamic i.e.: you can change it on the fly.Dynamic Padding to Reduce Compression Failures:Compression failures are expensive in terms of CPU. We go through the hoops of recompress, failure, reorganize, recompress, failure and finally page split. At the same time, how often we encounter compression failure depends largely on the compressibility of the data. In MySQL 5.6, courtesy of Facebook engineers, we have an adaptive algorithm based on per-index statistics that we gather about compression operations. The idea is that if a certain index/table is experiencing too many compression failures then we should try to pack the 16K uncompressed version of the page less densely i.e.: we let some space in the 16K page go unused in an attempt that the recompression won't end up in a failure. In other words, we dynamically keep adding 'pad' to the 16K page till we get compression failures within an agreeable range. It works the other way as well, that is we'll keep removing the pad if failure rate is fairly low. To tune the padding effort two configuration variables are exposed. innodb_compression_failure_threshold_pct: default 5, range 0 - 100,dynamic, implies the percentage of compress ops to fail before we start using to padding. Value 0 has a special meaning of disabling the padding. innodb_compression_pad_pct_max: default 50, range 0 - 75, dynamic, the  maximum percentage of uncompressed data page that can be reserved as pad.

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  • Triangle Strips and Tangent Space Normal Mapping

    - by Koarl
    Short: Do triangle strips and Tangent Space Normal mapping go together? According to quite a lot of tutorials on bump mapping, it seems common practice to derive tangent space matrices in a vertex program and transform the light direction vector(s) to tangent space and then pass them on to a fragment program. However, if one was using triangle strips or index buffers, it is a given that the vertex buffer contains vertices that sit at border edges and would thus require more than one normal to derive tangent space matrices to interpolate between in fragment programs. Is there any reasonable way to not have duplicate vertices in your buffer and still use tangent space normal mapping? Which one do you think is better: Having normal and tangent encoded in the assets and just optimize the geometry handling to alleviate the cost of duplicate vertices or using triangle strips and computing normals/tangents completely at run time? Thinking about it, the more reasonable answer seems to be the first one, but why might my professor still be fussing about triangle strips when it seems so obvious?

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  • Vertex Array Object (OpenGL)

    - by Shin
    I've just started out with OpenGL I still haven't really understood what Vertex Array Objects are and how they can be employed. If Vertex Buffer Object are used to store vertex data (such as their positions and texture coordinates) and the VAOs only contain status flags, where can they be used? What's their purpose? As far as I understood from the (very incomplete and unclear) GL Wiki, VAOs are used to set the flags/status for every vertex, following the order described in the Element Array Buffer, but the wiki was really ambiguous about it and I'm not really sure about what VAOs really do and how I could employ them.

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  • Multiple vulnerabilities in Thunderbird

    - by RitwikGhoshal
    CVE DescriptionCVSSv2 Base ScoreComponentProduct and Resolution CVE-2012-1948 Denial of service (DoS) vulnerability 9.3 Thunderbird Solaris 10 SPARC: 145200-12 X86: 145201-12 CVE-2012-1950 Address spoofing vulnerability 6.4 CVE-2012-1951 Resource Management Errors vulnerability 10.0 CVE-2012-1952 Resource Management Errors vulnerability 9.3 CVE-2012-1953 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 9.3 CVE-2012-1954 Resource Management Errors vulnerability 10.0 CVE-2012-1955 Address spoofing vulnerability 6.8 CVE-2012-1957 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability 4.3 CVE-2012-1958 Resource Management Errors vulnerability 9.3 CVE-2012-1959 Permissions, Privileges, and Access Controls vulnerability 5.0 CVE-2012-1961 Improper Input Validation vulnerability 4.3 CVE-2012-1962 Resource Management Errors vulnerability 10.0 CVE-2012-1963 Permissions, Privileges, and Access Controls vulnerability 4.3 CVE-2012-1964 Clickjacking vulnerability 4.0 CVE-2012-1965 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') vulnerability 4.3 CVE-2012-1966 Permissions, Privileges, and Access Controls vulnerability 4.3 CVE-2012-1967 Arbitrary code execution vulnerability 10.0 CVE-2012-1970 Denial of service (DoS) vulnerability 10.0 CVE-2012-1973 Resource Management Errors vulnerability 10.0 CVE-2012-3966 Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability 10.0 This notification describes vulnerabilities fixed in third-party components that are included in Oracle's product distributions.Information about vulnerabilities affecting Oracle products can be found on Oracle Critical Patch Updates and Security Alerts page.

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  • Pre-Loading von Tabellen in 11g

    - by Ulrike Schwinn (DBA Community)
    Tabellen und Indizes in den Cache zu laden, damit möglichst wenig I/O durchgeführt wird, ist eine häufig anzutreffende Anforderung. Diese Technik nennt man auch Pre-Loading oder Pre-Caching von Datenbank Objekten. Die Durchführung ist dabei sehr einfach. Gleich zu Beginn werden spezielle SQL Statements wie SELECT Statements mit Full Table Scan oder Index Scan durchgeführt, damit die entsprechenden Objekte vollständig in den Cache geladen werden können. Besonders interessant ist dieser Aspekt auch im Zusammenhang mit der Erstellung von Testumgebungen. Falls beispielsweise kein Warmup möglich ist, kann man bevor der eigentliche Test durchgeführt wird, bestimmte Tabellen und Indizes mit dieser Technik vorab in den Buffer Cache laden.  Der folgende Artikel zeigt wie man eine Tabelle in 11g in den Buffer Cache laden kann und gibt Tipps zur Durchführung.

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  • Read All Text from Textfile with Encoding in Windows RT

    - by jdanforth
    A simple extension for reading all text from a text file in WinRT with a specific encoding, made as an extension to StorageFile: public static class StorageFileExtensions {     async public static Task<string> ReadAllTextAsync(this StorageFile storageFile)     {         var buffer = await FileIO.ReadBufferAsync(storageFile);         var fileData = buffer.ToArray();         var encoding = Encoding.GetEncoding("Windows-1252");         var text = encoding.GetString(fileData, 0, fileData.Length);         return text;     } }

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  • How can I convert an image from raw data in Android without any munging?

    - by stephelton
    I have raw image data (may be png, jpg, ...) and I want it converted in Android without changing its pixel depth (bpp). In particular, when I load a grayscale (8 bpp) image that I want to use as alpha (glTexImage() with GL_ALPHA), it converts it to 16 bpp (presumably 5_6_5). While I do have a plan b (actually, I'm probably on plan 'e' by now, this is really becoming annoying) I would really like to discover an easy way to do this using what is readily available in the api. So far, I'm using BitmapFactory.decodeByteArray(). While I'm at it. I'm doing this from a native environment via jni (passing the buffer in from C, and a new buffer back to C from Java). Any portable solution in C/C++ would be preferable, but I don't want to introduce anything that might break in future versions of Android, etc.

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  • Speed up lighting in deferred shading

    - by kochol
    I implemented a simple deferred shading renderer. I use 3 G-Buffer for storing position (R32F), normal (G16R16F) and albedo (ARGB8). I use sphere map algorithm to store normals in world space. Currently I use inverse of view * projection matrix to calculate the position of each pixel from stored depth value. First I want to avoid per pixel matrix multiplication for calculating the position. Is there another way to store and calculate position in G-Buffer without the need of matrix multiplication Store the normal in view space Every lighting in my engine is in world space and I want do the lighting in view space to speed up my lighting pass. I want an optimized lighting pass for my deferred engine.

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  • Hardware instancing for voxel engine

    - by Menno Gouw
    i just did the tutorial on Hardware Instancing from this source: http://www.float4x4.net/index.php/2011/07/hardware-instancing-for-pc-in-xna-4-with-textures/. Somewhere between 900.000 and 1.000.000 draw calls for the cube i get this error "XNA Framework HiDef profile supports a maximum VertexBuffer size of 67108863." while still running smoothly on 900k. That is slightly less then 100x100x100 which are a exactly a million. Now i have seen voxel engines with very "tiny" voxels, you easily get to 1.000.000 cubes in view with rough terrain and a decent far plane. Obviously i can optimize a lot in the geometry buffer method, like rendering only visible faces of a cube or using larger faces covering multiple cubes if the area is flat. But is a vertex buffer of roughly 67mb the max i can work with or can i create multiple?

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  • How exactly does XNA's SpriteBatch work?

    - by David Gouveia
    To be more precise, if I needed to recreate this functionality from scratch in another API (e.g. in OpenGL) what would it need to be capable of doing? I do have a general idea of some of the steps, such as how it prepares an orthographic projection matrix and creates a quad for each draw call. I'm not too familiar, however, with the batching process itself. Are all quads stored in the same vertex buffer? Does it need an index buffer? How are different textures handled? If possible I'd be grateful if you could guide me through the process from when SpriteBatch.Begin() is called until SpriteBatch.End(), at least when using the default Deferred mode.

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  • Correct use of VAO's in OpenGL ES2 for iOS?

    - by sak
    I'm migrating to OpenGL ES2 for one of my iOS projects, and I'm having trouble to get any geometry to render successfully. Here's where I'm setting up the VAO rendering: void bindVAO(int vertexCount, struct Vertex* vertexData, GLushort* indexData, GLuint* vaoId, GLuint* indexId){ //generate the VAO & bind glGenVertexArraysOES(1, vaoId); glBindVertexArrayOES(*vaoId); GLuint positionBufferId; //generate the VBO & bind glGenBuffers(1, &positionBufferId); glBindBuffer(GL_ARRAY_BUFFER, positionBufferId); //populate the buffer data glBufferData(GL_ARRAY_BUFFER, vertexCount, vertexData, GL_STATIC_DRAW); //size of verte position GLsizei posTypeSize = sizeof(kPositionVertexType); glVertexAttribPointer(kVertexPositionAttributeLocation, kVertexSize, kPositionVertexTypeEnum, GL_FALSE, sizeof(struct Vertex), (void*)offsetof(struct Vertex, position)); glEnableVertexAttribArray(kVertexPositionAttributeLocation); //create & bind index information glGenBuffers(1, indexId); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, *indexId); glBufferData(GL_ELEMENT_ARRAY_BUFFER, vertexCount, indexData, GL_STATIC_DRAW); //restore default state glBindVertexArrayOES(0); glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0); glBindBuffer(GL_ARRAY_BUFFER, 0); } And here's the rendering step: //bind the frame buffer for drawing glBindFramebuffer(GL_FRAMEBUFFER, outputFrameBuffer); glClear(GL_COLOR_BUFFER_BIT); //use the shader program glUseProgram(program); glClearColor(0.4, 0.5, 0.6, 0.5); float aspect = fabsf(320.0 / 480.0); GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(GLKMathDegreesToRadians(65.0f), aspect, 0.1f, 100.0f); GLKMatrix4 modelViewMatrix = GLKMatrix4MakeTranslation(0.0f, 0.0f, -1.0f); GLKMatrix4 mvpMatrix = GLKMatrix4Multiply(projectionMatrix, modelViewMatrix); //glUniformMatrix4fv(projectionMatrixUniformLocation, 1, GL_FALSE, projectionMatrix.m); glUniformMatrix4fv(modelViewMatrixUniformLocation, 1, GL_FALSE, mvpMatrix.m); glBindVertexArrayOES(vaoId); glDrawElements(GL_TRIANGLE_FAN, kVertexCount, GL_FLOAT, &indexId); //bind the color buffer glBindRenderbuffer(GL_RENDERBUFFER, colorRenderBuffer); [context presentRenderbuffer:GL_RENDERBUFFER]; The screen is rendering the color passed to glClearColor correctly, but not the shape passed into bindVAO. Is my VAO being built correctly? Thanks!

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  • Multiple Vertex Buffers per Mesh

    - by Daniel
    I've run into the situation where the size of my mesh with all its vertices and indices, is larger than the (optimal) vertex buffer object upper limit (~8MB). I was wondering if I can sub-divide the mesh across multiple vertex buffers, and somehow retain validity of the indices. Ie a triangle with a indice at the first vertex, and an indice at the last (ie in seperate VBOs). All the while maintaining this within Vertex Array Objects. My thoughts are, save myself the hassle, and for meshes (messes :P) such as this, just use the necessary size ( 8MB); which is what I do at the moment. But ideally my buffer manager (wip) at the moment is using optimal sizes; I may just have to make a special case then... Any ideas? If necessary, a simple C++ code example is appreciated. Note: I have also cross-posted this on stackoverflow, as I was not sure as to which it would be more suitable (its partly a design question).

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