[Interest] Force Qt 5.4 to use ANGLE OpenGL ES 2 implementation

Sun Feb 15 10:08:43 CET 2015

Hi,

On 02/14/2015 08:05 PM, Roberto Garrido Martín wrote:
> Hi all,
>
> We have a windows Qt desktop app that links to a rendering library based
> on OpenGL ES 2.0.
> We want to assure that the app will run on as much as devices as
> possible, so we think that using ANGLE is a good idea.
> My question is: is there anything we can do to force our Qt 5.4 app to
> use ANGLE instead of the fallback sequence [OpenGL > 2.0 Driver] ->
> [ANGLE] -> [Software rasterizer] described here
> [http://blog.qt.io/blog/2014/11/27/qt-weekly-21-dynamic-opengl-implementation-loading-in-qt-5-4/]?

FTA, use the QT_OPENGL environment variable (set QT_OPENGL=angle) or the 
application attribute 
(QCoreApplication::setAttribute(Qt::AA_UseOpenGLES)). From your results 
below, it doesn't appear you've tried either.

Finally, you can also rebuild Qt with the -opengl es2 switch (which is 
on by default anyway). This will disable the dynamic GL feature and only 
use ANGLE.

> We have seleted the Qt-ANGLE Kit from QtCreator to build our app. It
> compiles, links, and deploys fine. I want to test the initialization
> sequence of the render library when ANGLE is used (we have to check the
> presence of some GL ES Extensions, and those have to be checked with
> EGL), but my dev machine has an OpenGL 4.4 capable Nvidia Graphics card,
> and apparently the fallback sequence is being launched, and Qt selects
> my OpenGL driver by default, instead of ANGLE.
>
> I have explicitly linked to QtANGLE’s implementation with -llibGLESv2
> -llibEGL, and used the QtANGLE’s OpenGL ES headers.
>
> Here the startup trace with GL debugging enabled (env variable
> QT_LOGGING_RULES = qt.qpa.gl <http://qt.qpa.gl>=true):
>
> ----------------------------------------------BEGIN
> TRACE---------------------------------------
> qt.qpa.gl <http://qt.qpa.gl>: OpenGL 2.0 entry points available
> qt.qpa.gl <http://qt.qpa.gl>: Qt: Using WGL and OpenGL from "opengl32.dll"
> qt.qpa.gl <http://qt.qpa.gl>: QOpenGLStaticContext::create OpenGL:
> "NVIDIA Corporation","GeForce GTX 570/PCIe/SSE2" default ContextFormat:
> v4.5 profile: 0 options: QFlags(0x4
> ),SampleBuffers, Extension-API present
> Extensions: 309
> qt.qpa.gl <http://qt.qpa.gl>:
> QWindowsIntegration::createPlatformOpenGLContext QSurfaceFormat(version
> 2.0, options QFlags(), depthBufferSize 24, redBufferSize -1, greenBuffer
> Size -1, blueBufferSize -1, alphaBufferSize -1, stencilBufferSize 8,
> samples -1, swapBehavior 2, swapInterval 1, profile  0)
> qt.qpa.gl <http://qt.qpa.gl>: "ARB::choosePixelFormat  Attributes:
>   0x2003 , 0x2027 , 0x2010 , 0x1 , 0x2001 , 0x1 , 0x2014 , 0x18 , 0x2011
> , 0x1 , 0x2022 , 0x18 , 0x2013 , 0x
> 202b , 0x201b , 0x8 , 0x2023 , 0x8 , 0x2041 , 0x0 ,
>     obtained px # 10  of  2
>      PIXELFORMATDESCRIPTOR dwFlags=0x8225 PFD_DRAW_TO_WINDOW
> PFD_SUPPORT_OPENGL PFD_SUPPORT_COMPOSITION PFD_DOUBLEBUFFER iPixelType=0
> cColorBits=32 cRedBit
> s=8 cRedShift=16 cGreenBits=8 cGreenShift=8 cBlueBits=8 cBlueShift=0
> cDepthBits=24 cStencilBits=8 cAuxBuffers=4 iLayerType=0 cAlphaBits=8
> cAlphaShift=24 cA
> ccumBits=64 cAccumRedBits=16 cAccumGreenBits=16 cAccumBlueBits=16
> cAccumAlphaBits=16"
> qt.qpa.gl <http://qt.qpa.gl>: ARB::createContext Creating context
> version 2 . 0 3 attributes
> qt.qpa.gl <http://qt.qpa.gl>: QWindowsGLContext::QWindowsGLContext
> 0x1179548 ARB  requested:  QSurfaceFormat(version 2.0, options QFlags(),
> depthBufferSize 24, redBufferSize
> -1, greenBufferSize -1, blueBufferSize -1, alphaBufferSize -1,
> stencilBufferSize 8, samples -1, swapBehavior 2, swapInterval 1, profile  0)
>      obtained # 10 ARB QSurfaceFormat(version 4.5, options QFlags(0x4),
> depthBufferSize 24, redBufferSize 8, greenBufferSize 8, blueBufferSize
> 8, alphaBuffe
> rSize 8, stencilBufferSize 8, samples 0, swapBehavior 2, swapInterval 1,
> profile  2)
>       PIXELFORMATDESCRIPTOR dwFlags=0x8225 PFD_DRAW_TO_WINDOW
> PFD_SUPPORT_OPENGL PFD_SUPPORT_COMPOSITION PFD_DOUBLEBUFFER iPixelType=0
> cColorBits=32 cRedBit
> s=8 cRedShift=16 cGreenBits=8 cGreenShift=8 cBlueBits=8 cBlueShift=0
> cDepthBits=24 cStencilBits=8 cAuxBuffers=4 iLayerType=0 cAlphaBits=8
> cAlphaShift=24 cA
> ccumBits=64 cAccumRedBits=16 cAccumGreenBits=16 cAccumBlueBits=16
> cAccumAlphaBits=16 swap interval: 1
>      default: ContextFormat: v4.5 profile: 0 options: QFlags(0x4)
>      HGLRC=0x30000
>
> ----------------------------------------------END
> TRACE---------------------------------------
>
> So it seems that OpenGL ES 2.0 and EGL are not being used. But, if we
> put these lines in the very beginning of the main function of the app:
>
> QSurfaceFormat format;
> format.setRenderableType(QSurfaceFormat::OpenGLES);
> QSurfaceFormat::setDefaultFormat(format);
>
> Then we have the following output:
>
> ----------------------------------------------BEGIN
> TRACE---------------------------------------
> qt.qpa.gl <http://qt.qpa.gl>: OpenGL 2.0 entry points available
> qt.qpa.gl <http://qt.qpa.gl>: Qt: Using WGL and OpenGL from "opengl32.dll"
> qt.qpa.gl <http://qt.qpa.gl>: QOpenGLStaticContext::create OpenGL:
> "NVIDIA Corporation","GeForce GTX 570/PCIe/SSE2" default ContextFormat:
> v4.5 profile: 0 options: QFlags(0x4
> ),SampleBuffers, Extension-API present
> Extensions: 309
> qt.qpa.gl <http://qt.qpa.gl>:
> QWindowsIntegration::createPlatformOpenGLContext QSurfaceFormat(version
> 2.0, options QFlags(), depthBufferSize 24, redBufferSize -1, greenBuffer
> Size -1, blueBufferSize -1, alphaBufferSize -1, stencilBufferSize 8,
> samples -1, swapBehavior 2, swapInterval 1, profile  0)
> Failed to create EGL context for format QSurfaceFormat(version 2.0,
> options QFlags(), depthBufferSize 24, redBufferSize -1, greenBufferSize
> -1, blueBufferS
> ize -1, alphaBufferSize -1, stencilBufferSize 8, samples -1,
> swapBehavior 2, swapInterval 1, profile  0) .
> This is most likely caused by not having the necessary graphics drivers
> installed.
> Install a driver providing OpenGL 2.0 or higher, or, if this is not
> possible, make sure the ANGLE Open GL ES 2.0 emulation libraries
> (libEGL.dll, libGLESv2
> .dll and d3dcompiler_*.dll) are available in the application
> executable's directory or in a location listed in PATH.
> ----------------------------------------------END
> TRACE---------------------------------------
>
> In this case, in spite of saying that WGL and OpenGL from “opengl32.dll”
> are being used by Qt, it tries to create an EGL context, and it fails.
> libEGL, libGLES and d3d_compiler dlls are in the same directory as the
> executable.
>
> Any ideas on how can we force GLES 2 ANGLE implementation?
> Thanks,
> Robert.
>
>
> --
> Website: http://robertogarrido.com
> Twitter: http://twitter.com/che1404
> LinkedIn: http://es.linkedin.com/in/robertogarrido/en
>
>
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Cheers,
Andrew