16.7內(nèi)建函數(shù)

HLSL有一個(gè)豐富的內(nèi)建函數(shù)的集合，它們對(duì)3D圖形來說非常有用。下表是一個(gè)刪減了的列表，注意：要得到更多的參考，可以參看DirectX文檔中內(nèi)建HLSL函數(shù)的完整列表。

以下表格中，//<variable>//表示變量variable的模（例如向量的絕對(duì)值）。

函數(shù)	描述
abs(x)	返回 |x|
ceil(x)	返回 ≥ x 的最小整數(shù)
clamp(x, a, b)	Clamps x to the range [a, b] and returns the result.
cross(u, v)	返回 u × v（叉積）
degrees(x)	轉(zhuǎn)換 x 從弧度到角度
determinant(M)	返回矩陣M的行列式det(M)
distance(u, v)	返回u點(diǎn)和v點(diǎn)之間的距離||v - u||
dot(u, v)	返回 u · v（點(diǎn)積）
floor(x)	返回 ≤ x 的最大整數(shù)
length(v)	返回 ||v||
lerp(u, v, t)	在u和v之間線性插值，參數(shù) t 在[0, 1 ]之間變化。
log(x)	返回 ln(x)
log10(x)	返回 log10(x)
log2(x)	返回 log2(x)
max(x, y)	如果x ≥ y，則返回 x；否則返回 y
min(x, y)	如果 x ≤ y，返回x；否則返回 y
mul(M, N)	返回矩陣乘積 MN. 注意：矩陣乘積必須是已定義的. 如果M是一個(gè)向量，它被作為一個(gè)行向量，則向量－矩陣（vector-matrix）乘法是已定義的。類似的,如果N 是一個(gè)向量，他被作為一個(gè)列向量，則矩陣－向量（matrix-vector）乘法是已定義的。
normalize(v)	返回 v/∥v∥
pow(b, n)	返回 bn
radians(x)	轉(zhuǎn)換 x 從 角度 到 弧度
reflect(v, n)	給定向量v和表面法線n，計(jì)算其反射向量
refract(v,n, eta)	給定向量v、表面法線n和兩種材質(zhì)的兩個(gè)索引的比率eta，計(jì)算其折射向量. 翻看一下物理書中Snell的規(guī)則或者在互聯(lián)網(wǎng)上搜索一下關(guān)于refraction（反射）的信息
rsqrt(x)	返回x的平方根的倒數(shù)
saturate(x)	返回clamp(x, 0.0, 1.0)
sin(x)	返回x的正弦,其中x單位為弧度
sincos(in x, out s, out c)	返回x的正弦和余弦，其中x單位為弧度
sqrt(x)	返回x的平方根
tan(x)	返回x的正切,其中 x 單位為弧度
transpose(M)	返回M的轉(zhuǎn)置

 

abs (Direct3D 9 HLSL)

Computes the absolute value of each component.

Syntax

ret abs(x)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	scalar, vector, or matrix	float, int	any
ret	out	same as input x	same as input x	same dimension(s) as input x

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_1_4

 

 

ceil (Direct3D 9 HLSL)

Returns the smallest integer which is greater than or equal to x.

Syntax

ret ceil(x)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	scalar, vector, or matrix	float	any
ret	out	same as input x	float	same dimension(s) as input x

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_2_0

 

 

clamp (Direct3D 9 HLSL)

Clamps x to the range [min, max].

Syntax

ret clamp(x, min, max)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	scalar, vector, or matrix	float, int	any
min	in	same as input x	float, int	same dimension(s) as input x
max	in	same as input x	float, int	same dimension(s) as input x
ret	out	same as input x	float, int	same dimension(s) as input x

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_1_4

 

cross (Direct3D 9 HLSL)

Returns the cross product of two 3D vectors.

Syntax

ret cross(x, y)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	vector	float	3
y	in	vector	float	3
ret	out	vector	float	3

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_1_4

 

 

degrees (Direct3D 9 HLSL)

Converts x from radians to degrees.

Syntax

ret degrees(x)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	scalar, vector, or matrix	float	any
ret	out	same as input x	float	same dimension(s) as input x

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_2_0

 

 

determinant (Direct3D 9 HLSL)

Returns the determinant of the square matrix m.

Syntax

ret determinant(m)

Where:

Name	In/Out	Template Type	Component Type	Size
m	in	matrix	float	any (number of rows = number of columns)
ret	out	scalar	float	1

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_1_4

 

distance (Direct3D 9 HLSL)

Returns the distance between two points x and y.

Syntax

ret distance(x, y)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	vector	float	any
y	in	vector	float	same dimension(s) as input x
ret	out	scalar	float	1

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_2_0

 

dot (Direct3D 9 HLSL)

Returns the • product of two vectors, x and y.

Syntax

ret dot(x, y)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	vector	float, int	any
y	in	vector	float, int	same dimensions(s) as input x
ret	out	scalar	float, int	1

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_1_1

 

 

floor (Direct3D 9 HLSL)

Returns the greatest integer which is less than or equal to x.

Syntax

ret floor(x)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	scalar, vector, or matrix	float	any
ret	out	same as input x	float	same dimension(s) as input x

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_2_0

 

 

 

length (Direct3D 9 HLSL)

Returns the length of the vector x.

Syntax

ret length(x)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	vector	float	any
ret	out	scalar	float	1

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_2_0

 

 

lerp (Direct3D 9 HLSL)

Returns x + s(y - x). This linearly interpolates between x and y, such that the return value is x when s is 0, and y when s is 1.

Syntax

ret lerp(x, y, s)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	scalar, vector, or matrix	float	any
y	in	same as input x	float	same dimension(s) as input x
s	in	same as input x	float	same dimension(s) as input x
ret	out	same as input x	float	same dimension(s) as input x

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_1_4

 

 

log (Direct3D 9 HLSL)

Returns the base-e logarithm of x. If x is negative, the function returns indefinite. If x is 0, the function returns +INF.

Syntax

ret log(x)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	scalar, vector, or matrix	float	any
ret	out	same as input x	float	same dimension(s) as input x

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_2_0

 

log10 (Direct3D 9 HLSL)

Returns the base-10 logarithm of x. If x is negative, the function returns indefinite. If x is 0, the function returns +INF.

Syntax

ret log10(x)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	scalar, vector, or matrix	float	any
ret	out	same as input x	float	same dimension(s) as input x

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_2_0

 

 

log2 (Direct3D 9 HLSL)

Returns the base-2 logarithm of x. If x is negative, the function returns indefinite. If x is 0, the function returns +INF.

Syntax

ret log2(x)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	scalar, vector, or matrix	float	any
ret	out	same as input x	float	same dimension(s) as input x

Minimum Shader Version

This intrinsic function is supported in the following (or above) shader versions:

Vertex Shader	Pixel Shader
vs_1_1	ps_2_0