Linearly change how much shadowing is done?

[hytel]

I have the VSG shadowing facility within my application working pretty well right now - even with cascading shadows. Where shadows fall, they turn the surfaces darker. If there was no ambient lighting, I imagine the shadow color would be black as in the demos. I'd like to just reduce the shadow effect on casted and self shadowed objects by a factor. But I don't want to do this by ramping up or changing the ambient lighting. Ambient lighting doesn't effect just the shadows, it effects all shading on models in the scene - even where there is no shadowing. Is there a way to just reduce the shadowing effect linearly without altering any of the lighting node values?

[robertosfield]

The PBR shaders are an attempt to render the world closer to how it's really lit so there isn't an attempt for implementing a psuedo lighting effect like you describe.

You can write your own shaders that do just what you want, just add vsg::AmbientLight with low intensity.

[AnyOldName3]

If you change the directional light to compensate for the change in the ambient, you should be able to make the rest of the scene stay around the same brightness while changing the brightness of the shadows.

Depending on the effect you're going for, though, this might well be an XY problem. Shadows blocking out the light that's shadowed is how things work in real life, so it should be what looks best. If your scene doesn't look good, it could be that it'd benefit from better placement of lights or the addition of post-process passes like bloom and tonemapping.

[hytel]

To give you some perspective, let's take the case where you don't have shadows, but you do have phong shading. In this case, sun comes from one side of an object making it brighter, and the other side darker. This looks pretty good. Let's say you have have just a bit of ambient lighting to make the darker side not black so you can decipher the intricacies of that side of the object's geometry. Now we add shadows. Here, I'm only really concerned with the self-shadows. I expect these areas to be darker too, but not completely black. Again, I can get that by keeping just a bit of ambient lighting. But, what if I want the self-shadows (that weren't there just a minute ago) less pronounced? Again, I like the normal phong shading I get without the shadows as a base. All I want to do is make the additional shadows less pronounced. But, to do this, I'm taking away the shading that I get for the non-shadowed areas by adding more ambient lighting. By the time I want just a faint shadow hint I have to make the object almost completely flat shaded! This is my dilemma. Does this make sense?

[robertosfield]

Perhaps you try creating a DirectionalLight with shadow maps enabled for it, and another DirectionalLight without shadow maps and set the intesnities to give you the strength of shadow vs lit areas. If the two DirectionalLights have the same direction the actual lighting from each will have the same characteristics.

[hytel]

Very intriguing! Right now I keep the directional light (with shadows) intensity at 1.0f because I love the normal phong lighting of the models, but I have an additional ambient light with intensity set at 0.03f to make sure detail can be seen on my models in the scene from the "dark side". So, what I should do is keep the directional light with shadows and the small ambient light, but add an additional directional light with the same direction and characteristics of the first, but with the shadows turned off. And, if I vary the intensity of this second directional light - I can backfill some light into the shadow areas?