From QRhi's perspective this consists of two things: - A shader with samplerExternalOES in it cannot go through the standard pipeline. Rather, a QShader with suitable GLSL code in it has to be constructed manually. As this is something useful as an autotest anyway, add a test case to the qshader autotest that demonstrates this. - When it comes to correctly calling glBindTexture, add a QRhiTexture flag. The expectation is that an OpenGL-only client sets this in combination with QRhiTexture::createFrom(), thus wrapping an existing texture that then gets bound to the GL_TEXTURE_EXTERNAL_OES target instead of our usual GL_TEXTURE_2D. For completeness we also add a SamplerExternalOES variable type to QShaderDescription, but the sampler type is not actually used by the QRhi OpenGL backend, as it is the QRhiTexture that defines the texture target. Change-Id: I36b52325deb3703b59186ee3d726d0c3015bfc4b Reviewed-by: Andy Nichols <andy.nichols@qt.io>