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Gamma correction: glEnable(GL_FRAMEBUFFER_SRGB) has no effect
I set up surface and texture format in QOpenGLWidget's ctor like this:
QSurfaceFormat format; format.setSamples(8); format.setColorSpace(QSurfaceFormat::sRGBColorSpace); setFormat(format); setTextureFormat(GL_SRGB8_ALPHA8);
With that, gamma correction is applied to the fragment shader output in the default FBO. At least, I can make a screenshot and get some pixel color, and it is approximately (1/2.2)-th power of the fragment shader's output color.
When I put glEnable(GL_FRAMEBUFFER_SRGB) or glDisable(GL_FRAMEBUFFER_SRGB) anywhere, it makes no difference. As far as I know, it is supposed to turn gamma correction on/off, but it does no such thing.
Yet on my other machine that same program produces output with gamma correction applied TWICE to it — all in the drawing operation writing to the default FBO. I need to put glDisable(GL_FRAMEBUFFER_SRGB) before it in order to make gamma correction applied only once.
Why it works that way? And how do I make my program work right on any device?
What graphic stack do you have on your devices ?
What version of Qt ?
What OS ?
OS is Windows 10 on both machines. It is the latest version of Qt (Qt updater informs me whenever new updates are available). Don't know what graphic stack is, but I have GeForce GTX 1050 with 2Gb RAM and OpenGL 4.6. QOpenGLFunctions_4_5_Core is used to call OpenGL functions.