_PPLAmbient

I am tearing shaders apart to learn ShaderLab. Could someone tell me what _PPLAmbient does. I guess it is a property that incoroprates the ambient light into the pass. Is there a list of these properties somewhere?

Code (csharp):

1.  
2.         Pass {
3.             Name "BASE"
4.             Tags {"LightMode" = "PixelOrNone"}
5.             Blend AppSrcAdd AppDstAdd
6.             Color [_PPLAmbient]
7.  

The whole shader is here.

http://www.unifycommunity.com/wiki/index.php?title=BumpColorSpec

 

PPLambient is the per pixel light ambient shader.
If you go to the resource section on the website you can download the sources of all standard included shaders which will give you the possibility to read it in detail (and learn from them naturally)

 

Thanx for the tips.

I am following along with the Unite08_Shaders video. Very interesting stuff.

I might as well add value

http://unity3d.com/support/resources/unite-presentations/shader-programming-course

Code (csharp):

1. Windows : C:\Program Files (x86)\Unity\Editor\Data\CGIncludes

 

I was pretty sure we could use _PPLAmbient in fixed functions shaders before. It's not working now, though. Is there something we can use instead, other than turning lighting on and using (2,2,2) as the ambient component? I tried UNITY_LIGHTMODEL_AMBIENT. That wasn't it.

 

PPL never worked in fixed function.
As the name implies its PerPixelLighting and per pixel means pixel shader ops.

On FFP hardware this always led to a straight jump to fallback if that use was in.


In the case of the original shader here its no topic anyway as that pass will be skipped from start on an FFP as it is set to PixelOrNone

 

No, I just downloaded Unity iPhone 1.7 and verified that it worked. The result is 50% of whatever you set in the Render Settings:

 

Unsure if this proofs anything as Unity iPhone 1.x has no support for per pixel at all, its always enforcing FFP and falling back to it.
On the other hand I just tried to recall an FFP counterpart to _PPLAmbient to get the ambient color for the shaderlab setup and can't recall one, but that does not mean anything as I know that traditional ambient lighting went through the hardware light 0 in DX and OGL (and as such a vertex light)

In case of the ambient it does not make a difference anyway cause ambient is an unpositional thing with no direction ie no "per pixel thing" that could be used for any per pixel effect on a pixel shader aside of just mixing it in as environmental light color on the lightmap for example

 

I'm not talking about a vertex lit shader. I just wanted to know if we had access to the color.

 

It seems to work yes.
Though unsure if it maps over a register or a texture

Technically the correct way doing ambient in FFP would be vertex lit as ambient is a vertex light, but Unity has various helpers and pseudo macros to drive stuff elsewhere too for usage in shaderlab and even cgprograms

 

Is that not what's going on in my screenshot above? I'm confused about what's happening, because it works fine in the Game View, but in order for it to work in the Scene View, the light button needs to be turned on.

Someone was asking me for help with a day-night shader, for which night is just multiplying in some blue. They brought up the idea of using the ambient light color, and I thought that it seemed a reasonable place to change a global variable. I figured I could test to see if this was any faster than using "Lighting On", but I can't test if it doesn't even work.

Do you know if using "Lighting On", with just an Ambient or Emissive term, is slower than using a ConstantColor?