Add support to define separate LEFT and RIGHT tile definitions

[derek-gerstmann]

We use displays which expect separate LEFT and RIGHT video signals, which are rendered on separate graphics cards. Ideally, it would be nice to add a tag to the tile definition of the display setting that maps left vs right eye, eg:

config {
display {
tiles {
host1
{
hostname = "localhost1";
t0x0L
{
stereoMode = "left";
device = 0;
}
t0x0R
{
stereoMode = "right";
device = 1;
}
}}}

Or something similar ....

[febret]

A possible implementation checklist:

• Add LeftOnly RightOnly stereoModes to DisplayTileConfig
• In DrawContext::drawFrame add an if block for the new stereo modes, calling renderer->draw with the appropriate eye set.
• If DisplayConfigBuilder support is desirable (i.e. to avoid having to enter each tile configuration manually), modify PlanarDisplayConfig so it supports lookup of two tiles with the same grid coordinates (ie 0x0) but different stereo modes. This would mostly entail changing the tile name lookup on line 71.

One potential issue that could require a bit more plumbing work. Tiles for planar configurations are supposed to be laid out in a grid (see the DisplayTileConfig isInGrid option). The grid right now expects a single tile given an index (ie 0x0). In this case, you would have two tiles for each grid index, with the second one in your config file overwriting the entry for the first one. (See https://github.com/uic-evl/omegalib/blob/master/src/omega/PlanarDisplayConfig.cpp#L78 and https://github.com/uic-evl/omegalib/blob/master/src/omega/DisplayTileConfig.cpp#L125).

The tile grid is currently used for two things:

• Fast generation of view rays from 2D pointers. (https://github.com/uic-evl/omegalib/blob/master/src/omega/DisplayConfig.cpp#L311) - this is going to work even if one tile overwrites the other as they have the same basic config.
• Setting up enabled tiles when launching multiple omegalib instances (https://github.com/uic-evl/omegalib/blob/master/src/omega/DisplayConfig.cpp#L224) This is not going to work as only one of the two tiles would get enabled.

[febret]

Possible solution to fix the tile grid issue:
change https://github.com/uic-evl/omegalib/blob/master/include/omega/DisplayConfig.h#L259

DisplayTileConfig* tileGrid[128][128];

to

static const int MAX_TILE_GRID_SIZE = 128;
vector<DisplayTileConfig*> tileGrid[MAX_TILE_GRID_SIZE][MAX_TILE_GRID_SIZE];

and change the code using tileGrid accordingly