MATX-305 : OSL structured file input

[kwokcb]

Update #1297

• Modify code generation to query and pass on colorspace information to top level uniforms.
• Change OSL filename syntax to be a structure. Current members include filename and colorspace but more can be added (such as for udim information which is currently additional arguments)
• Update OSL color3 / color4 image implementations to accept structure as input. Use string tokens to output arguments to texture() calls.
• Modify Syntax / TypeSytnax interface to accept string value extraction based on ShaderPort (which has typed inputs/outputs).
• Modify OSL shader code generation to emit structure as input argument.
• Modify GLSL introspection to query for colorspace information. Only used for reflection currently.
• Add new GenOption options to indicate whether to emit transforms if a color transform is found. Default is set to true.
• Set Arnold generation and rendering option to not emit transforms.

Results Sample MTLX file (found in /resources/Materials/TestSuite/stdlib/color_management). filename_cm_test.mtlx.txt Sample OSL generated using new structure shaderref1.osl.txt Sample OSL generate using new structure and passing colorspace shaderref1_arnold.osl.txt

[hodoulp]

Change OSL filename syntax to be a structure. Current members include filename and colorspace but more can be added (such as for udim information which is currently additional arguments)

[Newbie comment] That's an excellent idea so any later changes/improvements can be smoothly integrated. I made a comment about the name but I would also to highlight that colorspace string is used by the structure for the color space of the file to import but also by the document for the working color space. Is that ok to use the same string?

[kwokcb]

Change OSL filename syntax to be a structure. Current members include filename and colorspace but more can be added (such as for udim information which is currently additional arguments)

[Newbie comment] That's an excellent idea so any later changes/improvements can be smoothly integrated. I made a comment about the name but I would also to highlight that colorspace string is used by the structure for the color space of the file to import but also by the document for the working color space. Is that ok to use the same string?

Missed answering this:

1. There is a "colorspace" string member of the OSL source code structure.
2. The value of this data member is set using the "colorspace" attribute value associated with the filename for the image node inside a MaterialX document. ( It will be set to an empty string if no colorspace value is specified in the MaterialX document. )

Hope this makes things clear.