Here are a set of slides shows how the Teigha graphics engine works:
ODA chose OpenGL ES2 because it is cross-platform, supports mobile devices, is a strong standard, and is compatible with WebGL. This last item is important, because WebGL is used for cloud-based apps. The adoption of OpenGL allows for an immediate improvement in rendering quality of visual styles, like realistic, hidden, and so on. ODA has several dozen predefined visual styles employing 60 properties - including obscure ones like Jitter effect, opacity override, and shadows type.
It also allows per-face, per-vertex, and per-pixel lighting.
Visual style effects to be added soon:
- Intersection edges
- Overhang and jitter
- Order-dependent effects
Q: Are these rendering capabilities included in the CAD system when the developer implements the latest version of Teigha?
A: Yes, they are supported by the latest release of Teigha -- as well as more capabilities in upcoming releases.
Q: Are these visual styles demanding on hardware?
A: Visual styles can be turned off, if they are.
[Disclosure: ODA paid my airfare, hotel, and some meals]