This patch started out as a prototype for a retopology overlay. Before we started there were
several ideas how to tackle this issue (Frontface Backface and average back+front face shifting)
In the end we go the best results by mixing back and front depth buffers including a slider. With
this situation users can control what suits best for their needs.
And this patch needs a lot of testing it changes the Depth buffer and by doing that it can
intervene with the workings of other tools that needs the original depth buffer.
- fix depth fighting issues (rain model with mirror-modifier enabled)
Points of attention for future developments
- When slider is set to 0.0 we should not do any depth testing. As backfaces could become visible we should separate the color drawing and the alpha blending.
- Improve snapping tools with a collection to snap against. As how we could see it this collection might be selectable per mesh. The snapping tools will have an option to use this collection. (Use Retopology Collection) This needs a clear design and use cases.
- After the snapping tools we could improve the drawing of the retopology overlay by ignoring objects that are not inside this collection.
- Add option to draw the retopology faces using other colors like material viewport colors or vertex colors.
Notes from discussion with Retopoflow:
- experiment with average buffer in stead of the depth buffer
- what about migrating this overlay into the workbench engine (just like we do for tpaint) (future work?) the goal is for external add-ons to extend from the buffers with a DEPTH_EQUAL buffer.