Previously the sampler uniform declarations such as cogl_sampler0 were
generated by walking the list of layers in the shader state. This had
two problems. Firstly it would only generate the declarations for
layers that have been referenced. If a layer has a combine mode of
replace then the samplers from previous layers couldn't be used by
custom snippets. Secondly it meant that the samplers couldn't be
referenced by functions in the declarations sections because the
samplers are declared too late.
This patch fixes it to generate the layer declarations in the backend
start function using all of the layers on the pipeline instead. In
addition it adds the sampler declarations to the vertex shader as they
were previously missing.
Reviewed-by: Robert Bragg <robert@linux.intel.com>
(cherry picked from commit 1824df902bbb9995cae6ffb7a413913f2df35eef)
Conflicts:
cogl/driver/gl/cogl-pipeline-fragend-glsl.c
cogl/driver/gl/cogl-pipeline-vertend-glsl.c
a131b697d9