Unity provides a handful of builtin values for your shaders: things like current object’s transformation matrices, time etc.
Unity爲你在編寫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:物體矩陣爲 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
世界座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];
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)
時間的餘弦值
float4 _ProjectionParams : 投影參數
x is 1.0 or -1.0, negative if currently rendering with a flipped projection matrix
x爲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麼爲負。
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