343
edits
Compositor: Difference between revisions
no edit summary
No edit summary |
No edit summary |
||
| Line 255: | Line 255: | ||
Rendering dynamically to a cubemap is possible. As with shadow mapping, minimizing the object count and number of forward passes is vital to get good performance in FlightGear. Rendering to six cubemap faces requires six forward passes, but we can render to a dual paraboloid map instead, reducing this number to two. | Rendering dynamically to a cubemap is possible. As with shadow mapping, minimizing the object count and number of forward passes is vital to get good performance in FlightGear. Rendering to six cubemap faces requires six forward passes, but we can render to a dual paraboloid map instead, reducing this number to two. | ||
==== Transparency ==== | |||
When shadows (and multipass rendering in general) come into play, transparent objects have to be treated differently, even when we are dealing with a forward renderer. In OSG there are two ways to separate transparent surfaces: | |||
* Using RenderBins. After a single scene cull traversal, surfaces which belong to a special RenderBin type (DepthSortedBin) are removed or moved to another camera. This is how Rembrandt does it and it is the most backwards compatible approach since RenderBins can be changed directly inside Effects. | |||
* Using cull masks. Two separate traversals are done: one for opaque objects and another for translucent objects. This requires offering aircraft developers another way of tagging a surface as transparent. A trivial approach would be to add a new <animation> type called 'transparent', but that wouldn't be backwards compatible. Maybe we can add some kind of system where we can change cull masks inside Effects? Would that be too hacky or out of place? | |||
== TODO == | == TODO == | ||