高级着色语言HLSL入门（7）

max (Direct3D 9 HLSL)

Selects the greater of x and y.

Syntax

ret max(x, y)

Where:

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

min (Direct3D 9 HLSL)

Selects the lesser of x and y.

Syntax

ret min(x, y)

Where:

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

mul (Direct3D 9 HLSL)

Performs matrix multiplication between x and y. If x is a vector, it treated as a row vector. If y is a vector, it is treated as a column vector. The inner dimension x-columns and y-rows must be equal. The result has the dimension x-rows x y-columns.

Syntax

ret mul(x, y)

There are 9 overloaded versions of this function, to handle the different cases for the types and sizes of the x and y input arguments. The following table lists these versions.

Version	Name	Purpose	Template Type	Component Type	Size
1
	x	in	scalar	float, int	1
	y	in	scalar	same as input x	1
	ret	out	scalar	same as input x	1
2
	x	in	scalar	float, int	1
	y	in	vector	float, int	any
	ret	out	vector	float, int	same dimension(s) as input y
3
	x	in	scalar	float, int	1
	y	in	matrix	float, int	any
	ret	out	matrix	same as input y	same dimension(s) as input y
4
	x	in	vector	float, int	any
	y	in	scalar	float, int	1
	ret	out	vector	float, int	same dimension(s) as input x
5
	x	in	vector	float, int	any
	y	in	vector	float, int	same dimension(s) as input x
	ret	out	scalar	float, int	1
6
	x	in	vector	float, int	any
	y	in	matrix	float, int	rows = same dimension(s) as input x, columns = any
	ret	out	vector	float, int	same dimension(s) as input y columns
7
	x	in	matrix	float, int	any
	y	in	scalar	float, int	1
	ret	out	matrix	float, int	same dimension(s) as input x
8
	x	in	matrix	float, int	any
	y	in	vector	float, int	number of columns in input x
	ret	out	vector	float, int	number of rows in input x
9
	x	in	matrix	float, int	any
	y	in	matrix	float, int	rows = number of columns in input x
	ret	out	matrix	float, int	rows = number of rows in input x, columns = number of columns in input y

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

normalize (Direct3D 9 HLSL)

Returns the normalized vector x / length(x). If the length of x is 0, the result is indefinite.

Syntax

ret normalize(x)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	vector	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

pow (Direct3D 9 HLSL)

Returns x^y.

Syntax

ret pow(x, y)

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
ret	out	same as input x	float	same dimension(s) as input x

Remarks

Special cases:

• If x = 0, then the result will always be 0.
• If x < 0, there will be a compile error.

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

Vertex Shader	Pixel Shader
vs_1_1	ps_2_0

radians (Direct3D 9 HLSL)

Converts x from degrees to radians.

Syntax

ret radians(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_1_1

reflect (Direct3D 9 HLSL)

Returns the reflection vector v, given the entering ray direction i, and the surface normal n, as in:

v = i - 2 * dot(i, n) * n

Syntax

ret reflect(i, n)

Where:

Name	In/Out	Template Type	Component Type	Size
i	in	vector	float	any
n	in	vector	float	same dimension(s) as input i
ret	out	vector	float	same dimension(s) as input i

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

refract (Direct3D 9 HLSL)

Returns the refraction vector given the entering ray direction i, the surface normal n, and the refraction index ri. If the angle between i and n is too great for a given eta, refract returns (0,0,0).

Syntax

ret refract(i, n, ri)

Where:

Name	In/Out	Template Type	Component Type	Size
i	in	vector	float	any
n	in	vector	float	same dimension(s) as input i
ri	in	scalar	float	1
refraction vector	out	vector	float	same dimension(s) as input i

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

rsqrt (Direct3D 9 HLSL)

Returns 1 / sqrt(x).

Syntax

ret rsqrt(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

saturate (Direct3D 9 HLSL)

Clamps x to the range [0, 1].

Syntax

ret saturate(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_1_1

sin (Direct3D 9 HLSL)

Returns the sine of x.

Syntax

ret sin(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

sincos (Direct3D 9 HLSL)

Returns the sine and cosine of x. sin(x) is stored in the output parameter s. cos(x) is stored in the output parameter c.

Syntax

sincos(x, out s, out c)

Where:

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

sqrt (Direct3D 9 HLSL)

Square root (per component).

Syntax

ret sqrt(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

tan (Direct3D 9 HLSL)

Returns the tangent of x.

Syntax

ret tan(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

transpose (Direct3D 9 HLSL)

Returns the transpose of the input matrix x. If the dimensions of the source matrix is p-rows x q-columns, the resulting matrix is q-columns x p-rows.

Syntax

ret transpose(x)

Where:

Name	In/Out	Template Type	Component Type	Size
x	in	matrix	float, int, bool	any
ret	out	matrix	float, int, bool	rows = same number of columns as input x, columns = same number of rows 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_1

大多数函数已经重载以使其可以对所有内建类型有意义。例如，abs对所有数值类型有意义，所以它为所有这些数值类型进行了重载。又例如，叉积的叉乘仅对3D向量有意义，所以它对所有类型的3D向量（比如：int，float，double的3D向量）进行了重载。另一方面，线性插值——lerp，对于数值、2D、3D和4D向量有意义，因此重载了这些类型。

注意：如果你传递进去一个非数值类型到一个（要求）数值类型的函数，也就是一个仅能对数值类型进行操作的函数（比如：cos(x)），那么这个函数会对传进去的每个分量进行操作。例如，你写：

floats v = float3 (0.0f, 0.0f, 0.0f);

v = cos(v);

那么函数将会对每个分量进行操作：v=(cos(x),cos(y),cos(z))。

下例展示了这些固有的函数可能被调用的方式：

float x = sin(1.0f);       // sine of 1.0f radian.

float y = sqrt(4.0f);      // square root of 4.

vector u = {1.0f, 2.0f, -3.0f, 0.0f};

vector v = {3.0f, -1.0f, 0.0f, 2.0f};

float  s = dot(u, v);      // compute dot product of u and v.

float3 i = {1.0f, 0.0f, 0.0f};

float3 j = {0.0f, 1.0f, 0.0f};

float3 k = cross(i, j);    // compute cross product of i and j.

matrix<float, 2, 2> M = {1.0f, 2.0f, 3.0f, 4.0f};

matrix<float, 2, 2> T = transpose(M); // compute transpose