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>
c262a69851