Is it possible to apply an emissiveTexture to a multi material?

[bentwonk]

I have been playing with the worldmonger demo, and want to uses an emissive texture to overlay a grid upon the ground. I can do this with simple ground materials, but not with the more complex multi  material, is it possible to add an emmessive texture to a multi material such as the one used in Worldmonger?

[Wingnut]

Hi @bentwonk.  The MultiMaterial class is small and has no .emissiveTexture property.  You CAN, though, use the .emissiveTexture on each/any of the subMaterials... like this:

http://www.babylonjs-playground.com/#1XBLWB#180

(lines 39 and 45)

The Babylon decal feature has been "tried" as an on-ground (and terrain contour-following) "reticle" or target circle, but it had some problems on extremely bumpy grounds.  Also, our decal system is reasonably complicated and cannot be easily moved.  It is better... if re-created in the new place, and not "dragged" or animated across bumpy terrain.

There's another idea/method for putting BLACK grids on ANY section of heightMap, multi-material'd or not - with shadows/shadowGenerators and a spotlight (Our shadows are NOW available with ESM soft-edges and self-shadowing - see recent forum announcement).   (yay!)

Take a look at this playground, if you would.  http://playground.babylonjs.com/#1Z89KY#10

See how the images are only casting shadows... for the non-transparent parts of the image?  This means you could make a transparent-background grid image... and shine a spotlight through it (like the playground), but this light would shine straight down onto your ground... and would be easily position-able and size-able.  You would have a grid made of shadow, if everything goes correctly. 

I think it is limited to black... maybe.  It may have a circular outer ring/border... because spotlights are round.  Could THAT type of grid... work for your project?

With this type of grid, the grid is drawn "over" (atop) all non-terrain mesh, too (if mesh.receiveShadows = true).  It is a light from above, so it crosses EVERYTHING, if wanted. 

As far as I know, we have not had great success at sliding-around an image atop a bumpy heightMap.  (having it "terrain follow"... stretching nicely across mountain peaks and through deep valleys). 

A more advanced method... might be to create a second smaller heightMap, and it copies the Y height of each heightMap vertex... from the terrain below.  In other words, as you move-around this smaller "tile" of heightMap, it constantly re-transforms its vertices, matching the terrain contour beneath it.  Then ITS single diffuseTexture or emissiveTexture... could be a transparent-background grid image.

A constantly-transformed grid of "lines" (using Babylon LinesMesh class)... might be able to do a terrain-following grid in the same way, always setting its line "points"... to match the height of the verts beneath.  BUT... our linesMesh produces color-settable thin lines, with no thickness setting, so your grid might look a bit "wirey". 

Just some ideas.  Maybe others have more.  Hope this helps.  Issue still open... fellow forum folk.  Ideas welcome. 

[GameMonetize]

I like this one: http://playground.babylonjs.com/#1Z89KY#10. Did you do it @Wingnut?

[Wingnut]

Yeah, but I only assembled it from great tools and nice pics... done by others.  It has a strange "mood-feel", eh? 

Adam and Sebavan contributed, too.  Both of them fixed my forgotten .hasAlpha in lines 64 and 72. 

I wish I could draw 2d graphics that nice.  I'd be somebody. 

But really, it's BJS that makes it all easy.  YOU also contributed, artistically, @Deltakosh.  You answered a forum question:  "How do I put a different image on back side?" ... by suggesting a second plane.  That's when I added the back-side plane to it. 

So, it was a colossal team effort, which was a breeze for me.  Most important for me... is that this PG has helped 2 forum friends, so far, and might do many more.  Yay!    The playground app is the best learning tool EVER, I think.

[GameMonetize]

Love it even more then!