Unity provides a handful of builtin values for your shaders: things like current object's transformation matrices, time etc.
Unity為你在編寫shader是提供了少量的內置變量：類似 當前物體的變換矩陣，時間等。
You just use them in ShaderLab like you'd use any other property, the only difference is that you don't have to declare it somewhere - they are "built in".
你只能在ShaderLab中使用它們，就像你使用其他屬性一樣，唯一不同的是你不能聲明內置的變量。
Using them in programmable shaders requires including UnityCG.cginc file.
要用到這些內置變量你必須在你的shader程序中包含UnityCG.cginc file文件。
Transformations 變換
- float4x4 UNITY_MATRIX_MVP
-
Current model*view*projection matrix
當前物體*視*投影矩陣。（注：物體矩陣為 本地->世界） - float4x4 UNITY_MATRIX_MV
-
Current model*view matrix
當前物體*視矩陣 - float4x4 UNITY_MATRIX_P
-
Current projection matrix
當前物體*投影矩陣 - float4x4 UNITY_MATRIX_T_MV
-
Transpose of model*view matrix
轉置物體*視矩陣 - float4x4 UNITY_MATRIX_IT_MV
-
Inverse transpose of model*view matrix
逆轉置物體*視矩陣 - float4x4 UNITY_MATRIX_TEXTURE0 to UNITY_MATRIX_TEXTURE3
-
Texture transformation matrices
貼圖變換矩陣 - float4x4 _Object2World
-
Current model matrix
當前物體矩陣 - float4x4 _World2Object
-
Inverse of current world matrix
物體矩陣的逆矩陣 - float3 _WorldSpaceCameraPos
-
World space position of the camera
世界坐標空間中的攝像機位置 - float4 unity_Scale
-
xyz components unused; .w contains scale for uniformly scaled objects.
不適用xyz分量，而是通過w分量包含的縮放值等比縮放物體。
Lighting 光照
In plain ShaderLab, you access the following properties by appending zero at the end: e.g. the light's model*light color is _ModelLightColor0. In Cg shaders, they are exposed as arrays with a single element, so the same in Cg is _ModelLightColor[0].
在純粹的ShaderLab中，你可以利用下面這些屬性，只要在末尾增加一個零數：例如 燈光的物體*燈光顏色是_ModelLightColor0.在Cgshader中這些變量更像是一個包含單一元素的數組。所以在Cg中他們是這樣的_ModelLightColor[0];
| Name | Type | Value |
| _ModelLightColor | float4 | Material's Main * Light color 材質的主顏色*燈光顏色 |
| _SpecularLightColor | float4 | Material's Specular * Light color 材質的鏡面反射（高光）*燈光顏色。 |
| _ObjectSpaceLightPos | float4 | Light's position in object space. w component is 0 for directional lights, 1 for other lights 物體空間中的燈光為，平行光w分量為零其燈光為1； |
| _Light2World | float4x4 | Light to World space matrix 燈光轉世界空間矩陣 |
| _World2Light | float4x4 | World to Light space matrix 世界轉燈光空間矩陣 |
| _Object2Light | float4x4 | Object to Light space matrix 物體轉燈光空間矩陣 |
Various 變量
- float4 _Time : Time (t/20, t, t*2, t*3), use to animate things inside the shaders
時間： 用於Shasder中可動畫的地方。 - float4 _SinTime : Sine of time: (t/8, t/4, t/2, t)
時間的正弦值。 - float4 _CosTime : Cosine of time: (t/8, t/4, t/2, t)
時間的余弦值 - float4 _ProjectionParams : 投影參數
x is 1.0 or -1.0, negative if currently rendering with a flipped projection matrix
x為1.0 或者-1.0如果當前渲染使用的是一個反轉的投影矩陣那么為負。
y is camera's near plane y是攝像機的近剪裁平面
z is camera's far plane z是攝像機遠剪裁平面
w is 1/FarPlane. w是1/遠剪裁平面 - float4 _ScreenParams : 屏幕參數
x is current render target width in pixels x是當前渲染目標在像素值中寬度
y is current render target height in pixels y是當前渲染目標在像素值中的高度
z is 1.0 + 1.0/width z是1.0+1.0/寬度
w is 1.0 + 1.0/height w是1.0+1.0/高度