QOpenGLContext on Mac OS X
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Hi,
System: OS X 10.9, Qt 5.2.1 (installed view homebrew), Graphics: nvidia GTX 750M, Intel Iris Pro
I am new to OpenGL and Qt. For the last days I played with various examples, primarily using QGLWidget. I wanted to use the modern QOpenGLContext and tried this example here: http://qt-project.org/doc/qt-5.0/qtgui/openglwindow.html
When I change the following two lines:
@QSurfaceFormat format;
format.setSamples(4);@to:
@QSurfaceFormat format;
format.setDepthBufferSize( 24 );
format.setMajorVersion( 4 );
format.setMinorVersion( 3 );
format.setSamples( 4 );
format.setProfile( QSurfaceFormat::CoreProfile );
format.setOption( QSurfaceFormat::DebugContext );@The screen is black, no matter which version combination I use. The reason is I wanted to use some features of newer GLSL standards.
What am I doing wrong or missing?
Thanks a lot in advance!
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I figured out that for newer OpenGL versions, one must use VertexArrayObjects, otherwise it does not work. That fixed the problem.
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I'm just getting started myself, and I found the following code extremely useful. Just copy it into your initializeGL function before you do anything else.
@ // get context opengl-version
qDebug() << "Widget OpenGl: " << format().majorVersion() << "." << format().minorVersion();
qDebug() << "Context valid: " << context()->isValid();
qDebug() << "Really used OpenGl: " << context()->format().majorVersion() << "." << context()->format().minorVersion();
qDebug() << "OpenGl information: VENDOR: " << (const char*)glGetString(GL_VENDOR);
qDebug() << " RENDERDER: " << (const char*)glGetString(GL_RENDERER);
qDebug() << " VERSION: " << (const char*)glGetString(GL_VERSION);
qDebug() << " GLSL VERSION: " << (const char*)glGetString(GL_SHADING_LANGUAGE_VERSION);
@This is what you will see in the application output:
@Widget OpenGl: 4 . 1
Context valid: true
Really used OpenGl: 4 . 1
OpenGl information: VENDOR: ATI Technologies Inc.
RENDERDER: AMD Radeon HD - FirePro D300 OpenGL Engine
VERSION: 4.1 ATI-1.16.39
GLSL VERSION: 4.10
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That's nice of you, thanks a lot for sharing this snippet!