Mix lightmaps and dynamic shadows

Hello,

On the image above, I'm using precomputed lightmaps on the models except the cube. I want to mix them together with dynamic shadows but as you can see there is a different tinting of the shadow. This is because the dynamic shadow under the barn is blended with the lightmap (the directional light has the same angle as the light used for precomputing the lightmap).

What I would like to achieve is that the dynamic shadow of the cube can't be distinguished from the lightmap?

Thanks.

PS : I'm using Unity Pro 2.5.1

 

Thats out of your control I fear.
you can not affect the realtime shadow rendering

 

Couldn't you just increase the light's shadow "strength"? That would darken it (assuming it's not already at its maximum setting).

 

Thanks for the answers.

I tried the strength parameter of the shadows but it wasn't quite what I wanted.

I read an example of a shader which makes dynamic shadows desaturated, wouldn't it possible to adapt it to change the color of the resulting shadow or maybe use the shadow map information to make dynamic shadows only appear where there is no lightmap.

On a side question, when I looked at the builtin shaders sources, I didn't find information about how the shadows are displayed, is it a postprocess which can't be controlled?

Thanks.

 

I fear that shader is of no use as Unity's shadow shader is unavailable for modification.

Technology wise I would guess its a PSSM alike approach as unity isn't a deferred / forward rendering tech.

 

It seems to actually be possible with a little bit of contortion. I'm not sure if this technique will just steal back the performance gains from lightmapping but in the interest of theorycrafting and if you really, REALLY need to do it:

1. Split your directional light into two^H^H^Hthree^H^H^H^Htwo lights
2. Call them LightNoLightmap and LightLightmap
3. Create a layer for objects which have lightmaps and another layer for proxy objects
4. Set your LightNoLightmap to light everything except for the lightmapped layer
5. Set your LightLightmap to light only the lightmapped layer and proxy objects
6. Now create a proxy object for your player, this will be an invisible object with the same geometry as your player but with a shader that only casts shadows

It's... possible... but in most cases will probably run a lot slower than just using dynamic lights for everything.

 

Actually, for my original problem, I would have done something like using the dynamic shadow map where there is no lightmap (ie. where the lightmap is the whiter) and using the information from the lightmap where the two overlap.

I tried some things with a custom shader which did something like that but it had weird borders where the two overlapped because of the difference in lighting, my lightmap has occlusion and global illumination information.

Maybe I will try something like having additional information in my lightmap to modulate the dynamic shadow.

 

Only 1 layer definition is required:
- Lightmap layer

There are 5 elements in my test scene:
- Light for lightmap and proxies
- Light for everything except for lightmaps
- Player object
- Player proxy object (the same geometry/animation/transform as the player, but with a shader that renders it invisible yet still casts a shadow)
- Bench Object (Casts the lightmap)
- Ground Object (Lightmapped)


Place only the following objects in the lightmap layer:
- Ground object
- Player proxy object

Now set up one light to light only the lightmap layer, and another light for everything except for the lightmap layer.

The net effect is this:
1. The "light everything but lightmaps" light will cause the bench to cast a dynamic shadow on the player but not on the ground
2. The "light only lightmaps" light will cause the player proxy to cast a dynamic shadow on the ground

Effectively you've removed the bench's dynamic shadow from the ground, leaving you free to use static lightmaps for the shadow. It's not really that slow now that I've simplified it from what I originally envisioned, as each object only gets lit by one light except for the "player+player proxy" combination.