Texture projection, but inverted

Questions
1

Hi,

Please have a look here:
https://playground.babylonjs.com/#CQNGRK#620

This above is perfect to have a texture projected with light.

I would like to create unrealistic shadows, so I need the projected color to be black.

Currently, it is of the color of the diffuse. No way to make it black.
I tried with an inverted color image, it didn’t make it.

I would need a spotlight emitting… black light.

How may I do that?

Thanks

2

Huh. Just not sure I understand this correctly. A light cannot emit black light (in essence). However a light can be used to process shadows and then, shadows only. You can also look at the shadow only material or you could create/bake a shadowmap.
Apart from that, you’re gonna need a light (any light) to light your scene or your scene will just look plain black. Now, light only adds to light and given this. If the light that is lightening your scene is of an intensity of say 1 or 0.8 and you add a light which casts shadows with an intensity of -1 or -0.8, the light casting the shadows will add to the light with -1 value which when opposed to the +1 value of the scene light equals 0, meaning the highlights will not become brighter, only the shadows will (which if I understand correctly is what you mean when you say “a black light”, is it?

Here’s a PG where you can try casting shadows from a spot or a directional light with opposite intensity to the default hemi light that sets global lighting on the scene.

If this is not what you are seeking, may be you can try explain a bit more…
Else, have a great day :sunglasses:

1 Like
3

Thanks,

What I need is a way to project a texture, like a shadow, without surrounding light affecting the area.
See the white stripes on the ground on my PG?
They are lit, hence their diffuse color reacting to intensity.
I want them to be black or in shades of grey depending on the alpha (or any other trick, really).
I will update with a picture of what I am after exactly when back home, in less than an hour.

I am reluctant to use a shadow generator because I am aiming at a specific unrealistic lighting result.

:+1:

Edit: I know about the impossibility of a black light :grin:

Edit2: I just re read your answer and there is something to play with. Keep you updated

4

mawa?

You rock

Negative intensity was what I was after !

Thanks a lot :+1: :wave:

1 Like
5

Glad you found your way around this and if anything in my 'assessment 'helped out, I’m happy it somehow helped you, in the end.

Actually I didn’t; the link is broken. Certainly didn’t help providing an accurate answer.

Anyways, GJ you found the solution on your own :smiley: Now all that’s left for me is to wish you an amazing weekend :sunglasses:

2 Likes
6

Thank you so much mawa, wish you the best as well :wink:

2 Likes