GimelStudio / gsrenderer

An experimental C++ node evaluation engine and renderer for Gimel Studio

gsrenderer

An experimental C++ node evaluation engine and renderer created for Gimel Studio. However, the aim is to be general enough that any Python-based client UI could use this module as a backend.

Disclaimer: this is still at the idea stage. Nothing really works just yet.

If you'd like to help with this (either with ideas or code), please let us know by opening an issue here.

Goals

1. Node Evaluation Re-implement the basic node evaluation as a Python extension module via Pybind11. Currently, it is structured after a simple Python implementation, PyNodeEval.

2. Image I/O Implement Image I/O to support end-to-end evaluations.

3 Processing Optionally handle some rendering/processing of images with the ability to write Node evaluations in c++ in addition to Python.

Other possible ideas include creating a built-in gpu renderer for image processing which takes in a shader, etc.

Testing

For MSYS2 on Windows run:

• cmake -G "MSYS Makefiles" .
• cd tests
• make

Some Ideas

Work in progress. Subject to change.

There are three "global" renderer methods, gsrenderer.GetImage(), gsrenderer.SetImage() and gsrenderer.RenderImage().

• gsrenderer.GetImage() gets the image (stored in C++).
• gsrenderer.RenderImage() starts the node evaluation process (rendering).
• The method gsrenderer.SetImage() sets the image and is mainly used in the Python API to send a modified image back to gsrenderer so that the modified image can be accessed using gsrenderer.GetImage().

The node evaluating process sets the output image which is what is accessed by gsrenderer.GetImage(). To allow nodes to be written in Python, a base node class needs to be written that can be inherited from.

When the image stored in gsrenderer is changed, an event (e.g. EVT_RENDER_IMAGE_CHANGED) is sent which can then be binded to a function to (e.g. self.Bind(EVT_RENDER_IMAGE_CHANGED, self.OnRenderImageChanged)). The function can then call the required functions to refresh/update the viewport

• Add an empty method meant to be overridden in the Python subclass which acts as an update hook. Call this method when the image in gsrenderer is updated.