[osg-users] Multiple color layers for an osgTerrain::TerrainTile

[Leandro Linardos]

Hi,

I'm working with terrain data in a quad-tree structure at differents LODs. 

I want to show elevation data at LOD A and imagery data at level A+1, so, there are 4 color layers and 1 heightfield layer. I set the locators in each layer, so each one is well located. Each color layer (with the imagery data) covers only a quarter of the tile, fulfilling the remaing three quartes with black (in fact it depends on the wrap mode of the texture). Each tile quarter is composed with three black color areas and one imagery data area. 

In this scenary, the problem is that the imagery data is lost when are joined with the black area of the others layers. The result is black color painting all the tile.

Is there a way to fulfill the remaining of a layer with transparent color instead of black? Another ideas? Maybe there is something I'm not seeing.

(I get it working composing the 4 imagery images in one with the double of width and height, or adding the alpha 0 quartes directly in the source image getting 4 images with the double of width and height, but I would want use the data sources as they are, without preprocessing).

Thank you!

Cheers,
Leandro

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