On Tuesday, March 10th, NiranV Dean released version 184.108.40.206 of his Black Dragon viewer, which includes his recent work on volumetric lighting for Second Life, which I reported on at the start of March.
The update also includes a number of other fixes to some long standing rendering issues that Niran has been attempting to fix. Taken together, they are part of a larger update Niran has been planning, but as he comments in the release notes, he wanted to get these particular changes out to show people, and will save the rest for his upcoming version 2.4.2 release.
Graphics Memory Changes
The first of the changes Niran has made relates to the way in which graphics memory is used with textures. Generally, the viewer has one slider for setting a limit on the amount of texture memory, which encompasses everything you see in the viewer, including all of the UI elements. The is generally set to 512 Mb by default.
With the 220.127.116.11 release of Black Dragon, Niran has split how graphics memory is used between “global” textures – which include all the UI elements, etc., and the graphics memory currently being used to render the current scene – what you are actually seeing in-world at any moment in time.
The idea here is to provide the scene textures with their own “pool” of graphics memory, so they are no longer competing for graphics memory with all the other textures obtained from the region and the viewer’s UI textures, and should thus result in fewer issues of visible textures being “thrashed” (e.g. constantly switching between blurry and clear as they are swapped into and out of memory due to lack of space).
As I’m not a graphics or viewer rendering expert, I can offer no opinion on this approach. However, do note Niran’s recommendation to set texture memory to 512 Mb (the default upper limit for SL viewers, set several years ago to avoid OpenGL issues which might occur when setting large memory allocations) and the scene memory to 256 Mb.
Horizon and Other Rendering Fixes
One of the visual irritants in Second Life when running the view with the Advanced Lighting Model option (which Niran still refers to by its more technical name of “deferred rendering”), those living at altitude in-world (or flying at a few hundred metres above sea level), is the way in which the line of the horizon between “sky” and “sea” forms a concave curve across the screen, rather than a flat line as one might expect.
With Black Dragon 18.104.22.168, Niran has addressed this, and a few other horizon-related rendering issues so that – and again when running the viewer with Preferences > Display > Deferred Rendering (ALM) enabled, the horizon now appears as a horizontal line, as shown in the two images shown here, taken from Rebeca Bashly’s When Life Gives You Apples … Run.
Images of all the horizon rendering adjustments Niran has made can be found in his blog post on the release, linked to at the top and end of this article.