In the Built-in Render Pipeline, when using a Surface ShaderUnity’s code generation approach that makes it much easier to write lit shaders than using low level vertex/pixel shader programs. More info
See in Glossary, how lighting is applied and which Passes of the shaderA small script that contains the mathematical calculations and algorithms for calculating the Color of each pixel rendered, based on the lighting input and the Material configuration. More info
See in Glossary are used depends on which rendering pathThe technique Unity uses to render graphics. Choosing a different path affects the performance of your game, and how lighting and shading are calculated. Some paths are more suited to different platforms and hardware than others. More info
See in Glossary is used. Each pass in a shader communicates its lighting type via Pass Tags.
ForwardAddpasses are used.
Deferredpass is used.
PrepassFinalpasses are used.
VertexLMpasses are used.
ShadowCasterpass is used.
ForwardBase pass renders ambient, lightmapsA pre-rendered texture that contains the effects of light sources on static objects in the scene. Lightmaps are overlaid on top of scene geometry to create the effect of lighting. More info
See in Glossary, main directional light and not important (vertex/SH) lights at once.
ForwardAdd pass is used for any additive per-pixel lights; one invocation per object illuminated by such light is done. See Forward Rendering for details.
If forward rendering is used, but a shader does not have forward-suitable passes (i.e. neither
ForwardAdd pass types are present), then that object is rendered just like it would in Vertex Lit path, see below.
Deferred pass renders all information needed for lighting (in built-in shaders: diffuse color, specular color, smoothness,
world space normal, emission). It also adds lightmaps, reflection probes and ambient lighting into the emission channel. See Deferred Shading for details.
PrepassBase pass renders normals & specular exponent;
PrepassFinal pass renders final color by combining textures, lighting & emissive material properties. All regular in-scene lighting is done separately in screen-space. See Deferred Lighting for details.
Since vertex lighting is most often used on platforms that do not support programmable shaders, Unity can’t create multiple shader variants internally to handle lightmapped vs. non-lightmapped cases. So to handle lightmapped and non-lightmapped objects, multiple passes have to be written explicitly.
Vertexpass is used for non-lightmapped objects. All lights are rendered at once, using a fixed function OpenGL/Direct3D lighting model (Blinn-Phong)
VertexLMRGBMpass is used for lightmapped objects, when lightmaps are RGBM encoded (PC and consoles). No realtime lighting is applied; pass is expected to combine textures with a lightmap.
VertexLMpass is used for lightmapped objects, when lightmaps are double-LDR encoded (mobile platforms). No realtime lighting is applied; pass is expected to combine textures with a lightmap.