unity shader 內置變量

一、變換矩陣

UNITY_MATRIX_MVP　　從object space轉到 projection space（投影）

UNITY_MATRIX_MV 　　 從object space轉到camera space

UNITY_MATRIX_V　　     從world space轉到camera space

UNITY_MATRIX_P　　     從camera space轉到projection space

UNITY_MATRIX_VP　　 從world space轉到projection space

UNITY_MATRIX_T_MV   UNITY_MATRIX_MV 的轉置矩陣

UNITY_MATRIX_IT_MV  UNITY_MATRIX_MV的逆轉置矩陣，法線的矩陣轉換需要用變換矩陣的逆轉置矩陣.

_Object2World　　　　從object space轉到world space

_World2Object　　　　_Object2World的逆矩陣，從world space 到object space

二、Camera and screen

 

Name	Type	Value
_WorldSpaceCameraPos	float3	World space position of the camera. 相機的世界坐標
_ProjectionParams	float4	Xis 1.0 (or –1.0 if currently rendering with aflipped projection matrix),yis the camera’s near plane,zis the camera’s far plane andwis 1/FarPlane. x 值是1.0或-1.0（當為反轉的投影矩陣時） y 近截面，z遠截面，w 1/遠截面
_ScreenParams	float4	xis the camera’s render target width in pixels,yis the camera’s render target height in pixels,zis 1.0 + 1.0/width andwis 1.0 + 1.0/height. 屏幕尺寸x寬，y高，z 1+1.0/width,w 1+1.0/height
_ZBufferParams	float4	Used to linearize Z buffer values.xis (1-far/near),yis (far/near),zis (x/far) andwis (y/far). 用於線性化zbuffer
unity_OrthoParams	float4	xis orthographic camera’s width,yis orthographic camera’s height,zis unused andwis 1.0 when camera is orthographic, 0.0 when perspective. 正交攝像機的相關參數,w值1時是正交投影，0時是透視投影
unity_CameraProjection	float4x4	Camera’s projection matrix. 攝像機的投影矩陣
unity_CameraInvProjection	float4x4	Inverse of camera’s projection matrix. 攝像機的投影矩陣的逆矩陣
unity_CameraWorldClipPlanes[6]	float4	Camera frustum plane world space equations, in this order: left, right, bottom, top, near, far. 視錐體的左右下上遠近

 

三、Time

 

Name	Type	Value
_Time	float4	Time since level load (t/20, t, t*2, t*3), use to animate things inside the shaders.
_SinTime	float4	Sine of time: (t/8, t/4, t/2, t).
_CosTime	float4	Cosine of time: (t/8, t/4, t/2, t).
unity_DeltaTime	float4	Delta time: (dt, 1/dt, smoothDt, 1/smoothDt). 幀間隔時間

 

四、forward渲染的光照變量

Name	Type	Value
_LightColor0(declared in Lighting.cginc)	fixed4	Light color. 光線顏色
_WorldSpaceLightPos0	float4	Directional lights: (world space direction, 0). Other lights: (world space position, 1). World space 光照位置,平行光的w值為0，其他光源的w值為1
_LightMatrix0(declared in AutoLight.cginc)	float4x4	World-to-light matrix. Used to sample cookie & attenuation textures. World space轉到light space矩陣
unity_4LightPosX0, unity_4LightPosY0, unity_4LightPosZ0	float4	(ForwardBase pass only)world space positions of first four non-important point lights.
unity_4LightAtten0	float4	(ForwardBase pass only)attenuation factors of first four non-important point lights.
unity_LightColor	half4[4]	(ForwardBase pass only)colors of of first four non-important point lights.

 

五、延遲光照相關變量

Name	Type	Value
_LightColor	float4	Light color.光照顏色
_LightMatrix0	float4x4	World-to-light matrix. Used to sample cookie & attenuation textures. World space轉到light space矩陣

 

六、頂點光照相關變量

Name	Type	Value
unity_LightColor	half4[8]	Light colors. 光照顏色
unity_LightPosition	float4[8]	View-space light positions. (-direction,0) for directional lights; (position,1) for point/spot lights. View space光照位置，平行光的w值為0，其他光源的w值為1
unity_LightAtten	half4[8]	Light attenuation factors.xis cos(spotAngle/2) or –1 for non-spot lights;yis 1/cos(spotAngle/4) or 1 for non-spot lights;zis quadratic attenuation;wis squared light range. 光照衰減值
unity_SpotDirection	float4[8]	View-space spot light positions; (0,0,1,0) for non-spot lights. View space聚光燈位置