Opencl set for kernel args (#589)

Fixes #428

* Adds parsing (and tests) for SET command in pipeline command:
  * only for use with OPENCL-C shaders (errors out in other cases)
```
SET KERNEL ARG_NAME _name_ AS {datum_type} _value_
SET KERNEL ARG_NUMBER _number_ AS {datum_type} _value_
```
* Executor now invokes the pipeline to generate buffers for the PoD args
populated from SET commands
* Allow clustered pod args
* refactor opencl specific code in executor to its own loop
* Add end-to-end test
* Document SET command

1 files changed, 14 insertions, 0 deletions

diff --git a/docs/amber_script.md b/docs/amber_script.md
index a7a552c..93e97ba 100644
--- a/docs/amber_script.md
+++ b/docs/amber_script.md
@@ -275,6 +275,20 @@ attachment content, depth/stencil content, uniform buffers, etc.
   INDEX_DATA {buffer_name}
 ```
 
+##### OpenCL Plain-Old-Data Arguments
+OpenCL kernels can have plain-old-data (pod or pod_ubo in the desriptor map)
+arguments set their data via this command. Amber will generate the appropriate
+buffers for the pipeline populated with the specified data.
+
+```groovy
+  # Set argument |name| to |data_type| with value |val|.
+  SET KERNEL ARG_NAME _name_ AS {data_type} _val_
+
+  # Set argument |number| to |data_type| with value |val|.
+  # Arguments use 0-based numbering.
+  SET KERNEL ARG_NUMBER _number_ AS {data_type} _val_
+```
+
 ##### Topologies
  * `point_list`
  * `line_list`