Instead of passing SamplerInterfaceBlocks and a SamplerBindingMap to
Program, we now set a 'sampler group' per binding point:
Program::addSamplerGroup(...)
A sampler group here consists of a list of N 'Sampler' and a 'Sampler'
is just a unique name (unifrom name in the shader) and binding point in
the shader.
That's all the driver layer needs.
With this change we get rid of the code that re-created the uniform
names in the driver -- this should never have been done there. And we
also remove the hash-map lookups in vulkan and metal drivers.
Program::shader() was taking a string before which didn't make sense
for spirv. Now it's just a blob, in the case of GL/Metal, the blob
must be a null terminated c-string, and the size must include the
terminating null character.
This fixes an out-of-bound access in ShaderBuilder::getShader() (which
doesn't exist anymore), because it was creating a CString passing
a size that included the null terminating char, which is not was CString
expects. CString can now assert() in that case.
driver::Program now uses a std::vector<> for storage, which we should
fix at some point (b/c it's a public header). CString was not suited to
store binary blobs.
