Static Batching and Per Pixel Lighting

[candycat]

I want to figure out whether per pixel lighting breaks static batching. The doc says: The draw calls for “additional per-pixel lights” will not be batched. But it’s only for dynamic batching.

And i found this post. Alexey said:

the problem with batching + per-pixel lighting is:
when you need to do multi-pass rendering (several per-pixel lights, important point/spot lights) you want to make sure that your transformed geometry matches exactly between passes (otherwise your depth check will be screwed). Due to this we stop batching the geometry when you want multi-pass render.
…
EDIT: sure, the problem is with runtime batching (we transform vertices at runtime) - static batching (or some kind of one-time combine meshes script) should do the trick.

And i thought static batching will not be affected by per-pixel lighting.

However, i built a scene with two cubes (with the same material, using default bumped diffuse shader), and set them “static”. i also create one directional light and five point lights (set to “Important”). And the result is 11 draw calls. If i set the point lights to “Not important”, the draw calls is 2. If i delete point lights, the draw calls is 1.

So, do Per Pixel Lights break static batching? And why the draw calls is 2 when all point lights “Not important”?

[fffMalzbier]

If the light is to not important the lights will fall back to vertex lighting.
Its not as accurate but all the light information will be merged and rendered in one pass

Rendering of each object happens as follows:

• Base Pass applies one per-pixel directional light and all per-vertex/SH lights.
• Other per-pixel lights are rendered in additional passes, one pass for each light.

Unity - Manual: Forward rendering path