Unity Shader 内置函数

编写Unity Shader时有很多内置函数，在网上查找了一些，把他们记录了下来，以供大家参考使用

参考网址：http://www.cppblog.com/lai3d/archive/2008/10/23/64889.html

这个是MSDN上的，DirectX Documentation里也有，其实也就是HLSL的内置函数

Intrinsic Functions (DirectX HLSL)

The following table lists the intrinsic functions available in HLSL. Each function has a brief description, and a link to a reference page that has more detail about the input argument and return type.

Name	Syntax	Description
abs	abs(x)	Absolute value (per component).
acos	acos(x)	Returns the arccosine of each component of x.
all	all(x)	Test if all components of x are nonzero.
any	any(x)	Test if any component of x is nonzero.
asfloat	asfloat(x)	Convert the input type to a float.
asin	asin(x)	Returns the arcsine of each component of x.
asint	asint(x)	Convert the input type to an integer.
asuint	asuint(x)	Convert the input type to an unsigned integer.
atan	atan(x)	Returns the arctangent of x.
atan2	atan2(y, x)	Returns the arctangent of of two values (x,y).
ceil	ceil(x)	Returns the smallest integer which is greater than or equal to x.
clamp	clamp(x, min, max)	Clamps x to the range [min, max].
clip	clip(x)	Discards the current pixel, if any component of x is less than zero.
cos	cos(x)	Returns the cosine of x.
cosh	cosh(x)	Returns the hyperbolic cosine of x.
cross	cross(x, y)	Returns the cross product of two 3D vectors.
D3DCOLORtoUBYTE4	D3DCOLORtoUBYTE4(x)	Swizzles and scales components of the 4D vector x to compensate for the lack of UBYTE4 support in some hardware.
ddx	ddx(x)	Returns the partial derivative of x with respect to the screen-space x-coordinate.
ddy	ddy(x)	Returns the partial derivative of x with respect to the screen-space y-coordinate.
degrees	degrees(x)	Converts x from radians to degrees.
determinant	determinant(m)	Returns the determinant of the square matrix m.
distance	distance(x, y)	Returns the distance between two points.
dot	dot(x, y)	Returns the dot product of two vectors.
exp	exp(x)	Returns the base-e exponent.
exp2	exp2(x)	Base 2 exponent (per component).
faceforward	faceforward(n, i, ng)	Returns -n * sign(•(i, ng)).
floor	floor(x)	Returns the greatest integer which is less than or equal to x.
fmod	fmod(x, y)	Returns the floating point remainder of x/y.
frac	frac(x)	Returns the fractional part of x.
frexp	frexp(x, exp)	Returns the mantissa and exponent of x.
fwidth	fwidth(x)	Returns abs(ddx(x)) + abs(ddy(x))
GetRenderTargetSampleCount	GetRenderTargetSampleCount()	Returns the number of render-target samples.
GetRenderTargetSamplePosition	GetRenderTargetSamplePosition(x)	Returns a sample position (x,y) for a given sample index.
isfinite	isfinite(x)	Returns true if x is finite, false otherwise.
isinf	isinf(x)	Returns true if x is +INF or -INF, false otherwise.
isnan	isnan(x)	Returns true if x is NAN or QNAN, false otherwise.
ldexp	ldexp(x, exp)	Returns x * 2exp
length	length(v)	Returns the length of the vector v.
lerp	lerp(x, y, s)	Returns x + s(y - x).
lit	lit(n • l, n • h, m)	Returns a lighting vector (ambient, diffuse, specular, 1)
log	log(x)	Returns the base-e logarithm of x.
log10	log10(x)	Returns the base-10 logarithm of x.
log2	log2(x)	Returns the base-2 logarithm of x.
max	max(x, y)	Selects the greater of x and y.
min	min(x, y)	Selects the lesser of x and y.
modf	modf(x, out ip)	Splits the value x into fractional and integer parts.
mul	mul(x, y)	Performs matrix multiplication using x and y.
noise	noise(x)	Generates a random value using the Perlin-noise algorithm.
normalize	normalize(x)	Returns a normalized vector.
pow	pow(x, y)	Returns xy.
radians	radians(x)	Converts x from degrees to radians.
reflect	reflect(i, n)	Returns a reflection vector.
refract	refract(i, n, R)	Returns the refraction vector.
round	round(x)	Rounds x to the nearest integer
rsqrt	rsqrt(x)	Returns 1 / sqrt(x)
saturate	saturate(x)	Clamps x to the range [0, 1]
sign	sign(x)	Computes the sign of x.
sin	sin(x)	Returns the sine of x
sincos	sincos(x, out s, out c)	Returns the sine and cosine of x.
sinh	sinh(x)	Returns the hyperbolic sine of x
smoothstep	smoothstep(min, max, x)	Returns a smooth Hermite interpolation between 0 and 1.
sqrt	sqrt(x)	Square root (per component)
step	step(a, x)	Returns (x >= a) ? 1 : 0
tan	tan(x)	Returns the tangent of x
tanh	tanh(x)	Returns the hyperbolic tangent of x
tex1D	tex1D(s, t)	1D texture lookup.
tex1Dbias	tex1Dbias(s, t)	1D texture lookup with bias.
tex1Dgrad	tex1Dgrad(s, t, ddx, ddy)	1D texture lookup with a gradient.
tex1Dlod	tex1Dlod(s, t)	1D texture lookup with LOD.
tex1Dproj	tex1Dproj(s, t)	1D texture lookup with projective divide.
tex2D	tex2D(s, t)	2D texture lookup.
tex2Dbias	tex2Dbias(s, t)	2D texture lookup with bias.
tex2Dgrad	tex2Dgrad(s, t, ddx, ddy)	2D texture lookup with a gradient.
tex2Dlod	tex2Dlod(s, t)	2D texture lookup with LOD.
tex2Dproj	tex2Dproj(s, t)	2D texture lookup with projective divide.
tex3D	tex3D(s, t)	3D texture lookup.
tex3Dbias	tex3Dbias(s, t)	3D texture lookup with bias.
tex3Dgrad	tex3Dgrad(s, t, ddx, ddy)	3D texture lookup with a gradient.
tex3Dlod	tex3Dlod(s, t)	3D texture lookup with LOD.
tex3Dproj	tex3Dproj(s, t)	3D texture lookup with projective divide.
texCUBE	texCUBE(s, t)	Cube texture lookup.
texCUBEbias	texCUBEbias(s, t)	Cube texture lookup with bias.
texCUBEgrad	texCUBEgrad(s, t, ddx, ddy)	Cube texture lookup with a gradient.
texCUBElod	tex3Dlod(s, t)	Cube texture lookup with LOD.
texCUBEproj	texCUBEproj(s, t)	Cube texture lookup with projective divide.
transpose	transpose(m)	Returns the transpose of the matrix m.
trunc	trunc(x)	Truncates floating-point value(s) to integer value(s)

表 3-1 HLSL内置函数

函数名 用法

abs 计算输入值的绝对值。
acos 返回输入值反余弦值。
all 测试非0值。
any 测试输入值中的任何非零值。
asin 返回输入值的反正弦值。
atan 返回输入值的反正切值。
atan2 返回y/x的反正切值。
ceil 返回大于或等于输入值的最小整数。
clamp 把输入值限制在[min, max]范围内。
clip 如果输入向量中的任何元素小于0，则丢弃当前像素。
cos 返回输入值的余弦。
cosh 返回输入值的双曲余弦。
cross 返回两个3D向量的叉积。
ddx 返回关于屏幕坐标x轴的偏导数。
ddy 返回关于屏幕坐标y轴的偏导数。
degrees 弧度到角度的转换
determinant 返回输入矩阵的值。
distance 返回两个输入点间的距离。
dot 返回两个向量的点积。
exp 返回以e为底数，输入值为指数的指数函数值。
exp2 返回以2为底数，输入值为指数的指数函数值。
faceforward 检测多边形是否位于正面。
floor 返回小于等于x的最大整数。
fmod 返回a / b的浮点余数。
frac 返回输入值的小数部分。
frexp 返回输入值的尾数和指数
fwidth 返回 abs ( ddx (x) + abs ( ddy(x))。
isfinite 如果输入值为有限值则返回true，否则返回false。
isinf 如何输入值为无限的则返回true。
isnan 如果输入值为NAN或QNAN则返回true。
ldexp frexp的逆运算，返回 x * 2 ^ exp。
len / lenth 返回输入向量的长度。
lerp 对输入值进行插值计算。
lit 返回光照向量（环境光，漫反射光，镜面高光，1）。
log 返回以e为底的对数。
log10 返回以10为底的对数。
log2 返回以2为底的对数。
max 返回两个输入值中较大的一个。
min 返回两个输入值中较小的一个。
modf 把输入值分解为整数和小数部分。
mul 返回输入矩阵相乘的积。
normalize 返回规范化的向量，定义为 x / length(x)。
pow 返回输入值的指定次幂。
radians 角度到弧度的转换。
reflect 返回入射光线i对表面法线n的反射光线。
refract 返回在入射光线i，表面法线n，折射率为eta下的折射光线v。
round 返回最接近于输入值的整数。
rsqrt 返回输入值平方根的倒数。
saturate 把输入值限制到[0, 1]之间。
sign 计算输入值的符号。
sin 计算输入值的正弦值。
sincos 返回输入值的正弦和余弦值。
sinh 返回x的双曲正弦。
smoothstep 返回一个在输入值之间平稳变化的插值。
sqrt 返回输入值的平方根。
step 返回（x >= a）? 1 : 0。
tan 返回输入值的正切值。
fanh 返回输入值的双曲线切线。
transpose 返回输入矩阵的转置。
tex1D* 1D纹理查询。
tex2D* 2D纹理查询。
tex3D* 3D纹理查询。

texCUBE* 立方纹理查询。

Intrinsic Functions (DirectX HLSL)

The following table lists the intrinsic functions available in HLSL. Each function has a brief description, and a link to a reference page that has more detail about the input argument and return type.

Name	Description	Minimum shader model
abs	Absolute value (per component).	11
acos	Returns the arccosine of each component of x.	11
all	Test if all components of x are nonzero.	11
AllMemoryBarrier	Blocks execution of all threads in a group until all memory accesses have been completed.	5
AllMemoryBarrierWithGroupSync	Blocks execution of all threads in a group until all memory accesses have been completed and all threads in the group have reached this call.	5
any	Test if any component of x is nonzero.	11
asdouble	Reinterprets a cast value into a double.	5
asfloat	Convert the input type to a float.	4
asin	Returns the arcsine of each component of x.	11
asint	Convert the input type to an integer.	4
asuint	Reinterprets the bit pattern of a 64-bit type to a uint.	5
asuint	Convert the input type to an unsigned integer.	4
atan	Returns the arctangent of x.	11
atan2	Returns the arctangent of of two values (x,y).	11
ceil	Returns the smallest integer which is greater than or equal to x.	11
clamp	Clamps x to the range [min, max].	11
clip	Discards the current pixel, if any component of x is less than zero.	11
cos	Returns the cosine of x.	11
cosh	Returns the hyperbolic cosine of x.	11
countbits	Counts the number of bits (per component) in the input integer.	5
cross	Returns the cross product of two 3D vectors.	11
D3DCOLORtoUBYTE4	Swizzles and scales components of the 4D vector xto compensate for the lack of UBYTE4 support in some hardware.	11
ddx	Returns the partial derivative of x with respect to the screen-space x-coordinate.	21
ddx_coarse	Computes a low precision partial derivative with respect to the screen-space x-coordinate.	5
ddx_fine	Computes a high precision partial derivative with respect to the screen-space x-coordinate.	5
ddy	Returns the partial derivative of x with respect to the screen-space y-coordinate.	21
ddy_coarse	Computes a low precision partial derivative with respect to the screen-space y-coordinate.	5
ddy_fine	Computes a high precision partial derivative with respect to the screen-space y-coordinate.	5
degrees	Converts x from radians to degrees.	11
determinant	Returns the determinant of the square matrix m.	11
DeviceMemoryBarrier	Blocks execution of all threads in a group until all device memory accesses have been completed.	5
DeviceMemoryBarrierWithGroupSync	Blocks execution of all threads in a group until all device memory accesses have been completed and all threads in the group have reached this call.	5
distance	Returns the distance between two points.	11
dot	Returns the dot product of two vectors.	1
dst	Calculates a distance vector.	5
EvaluateAttributeAtCentroid	Evaluates at the pixel centroid.	5
EvaluateAttributeAtSample	Evaluates at the indexed sample location.	5
EvaluateAttributeSnapped	Evaluates at the pixel centroid with an offset.	5
exp	Returns the base-e exponent.	11
exp2	Base 2 exponent (per component).	11
f16tof32	Converts the float16 stored in the low-half of the uint to a float.	5
f32tof16	Converts an input into a float16 type.	5
faceforward	Returns -n * sign(dot(i, ng)).	11
firstbithigh	Gets the location of the first set bit starting from the highest order bit and working downward, per component.	5
firstbitlow	Returns the location of the first set bit starting from the lowest order bit and working upward, per component.	5
floor	Returns the greatest integer which is less than or equal to x.	11
fmod	Returns the floating point remainder of x/y.	11
frac	Returns the fractional part of x.	11
frexp	Returns the mantissa and exponent of x.	21
fwidth	Returns abs(ddx(x)) + abs(ddy(x))	21
GetRenderTargetSampleCount	Returns the number of render-target samples.	4
GetRenderTargetSamplePosition	Returns a sample position (x,y) for a given sample index.	4
GroupMemoryBarrier	Blocks execution of all threads in a group until all group shared accesses have been completed.	5
GroupMemoryBarrierWithGroupSync	Blocks execution of all threads in a group until all group shared accesses have been completed and all threads in the group have reached this call.	5
InterlockedAdd	Performs a guaranteed atomic add of value to the dest resource variable.	5
InterlockedAnd	Performs a guaranteed atomic and.	5
InterlockedCompareExchange	Atomically compares the input to the comparison value and exchanges the result.	5
InterlockedCompareStore	Atomically compares the input to the comparison value.	5
InterlockedExchange	Assigns value to dest and returns the original value.	5
InterlockedMax	Performs a guaranteed atomic max.	5
InterlockedMin	Performs a guaranteed atomic min.	5
InterlockedOr	Performs a guaranteed atomic or.	5
InterlockedXor	Performs a guaranteed atomic xor.	5
isfinite	Returns true if x is finite, false otherwise.	11
isinf	Returns true if x is +INF or -INF, false otherwise.	11
isnan	Returns true if x is NAN or QNAN, false otherwise.	11
ldexp	Returns x * 2exp	11
length	Returns the length of the vector v.	11
lerp	Returns x + s(y - x).	11
lit	Returns a lighting vector (ambient, diffuse, specular, 1)	11
log	Returns the base-e logarithm of x.	11
log10	Returns the base-10 logarithm of x.	11
log2	Returns the base-2 logarithm of x.	11
mad	Performs an arithmetic multiply/add operation on three values.	5
max	Selects the greater of x and y.	11
min	Selects the lesser of x and y.	11
modf	Splits the value x into fractional and integer parts.	11
mul	Performs matrix multiplication using x and y.	1
noise	Generates a random value using the Perlin-noise algorithm.	11
normalize	Returns a normalized vector.	11
pow	Returns xy.	11
Process2DQuadTessFactorsAvg	Generates the corrected tessellation factors for a quad patch.	5
Process2DQuadTessFactorsMax	Generates the corrected tessellation factors for a quad patch.	5
Process2DQuadTessFactorsMin	Generates the corrected tessellation factors for a quad patch.	5
ProcessIsolineTessFactors	Generates the rounded tessellation factors for an isoline.	5
ProcessQuadTessFactorsAvg	Generates the corrected tessellation factors for a quad patch.	5
ProcessQuadTessFactorsMax	Generates the corrected tessellation factors for a quad patch.	5
ProcessQuadTessFactorsMin	Generates the corrected tessellation factors for a quad patch.	5
ProcessTriTessFactorsAvg	Generates the corrected tessellation factors for a tri patch.	5
ProcessTriTessFactorsMax	Generates the corrected tessellation factors for a tri patch.	5
ProcessTriTessFactorsMin	Generates the corrected tessellation factors for a tri patch.	5
radians	Converts x from degrees to radians.	1
rcp	Calculates a fast, approximate, per-component reciprocal.	5
reflect	Returns a reflection vector.	1
refract	Returns the refraction vector.	11
reversebits	Reverses the order of the bits, per component.	5
round	Rounds x to the nearest integer	11
rsqrt	Returns 1 / sqrt(x)	11
saturate	Clamps x to the range [0, 1]	1
sign	Computes the sign of x.	11
sin	Returns the sine of x	11
sincos	Returns the sine and cosine of x.	11
sinh	Returns the hyperbolic sine of x	11
smoothstep	Returns a smooth Hermite interpolation between 0 and 1.	11
sqrt	Square root (per component)	11
step	Returns (x >= a) ? 1 : 0	11
tan	Returns the tangent of x	11
tanh	Returns the hyperbolic tangent of x	11
tex1D(s, t)	1D texture lookup.	1
tex1D(s, t, ddx, ddy)	1D texture lookup.	21
tex1Dbias	1D texture lookup with bias.	21
tex1Dgrad	1D texture lookup with a gradient.	21
tex1Dlod	1D texture lookup with LOD.	31
tex1Dproj	1D texture lookup with projective divide.	21
tex2D(s, t)	2D texture lookup.	11
tex2D(s, t, ddx, ddy)	2D texture lookup.	21
tex2Dbias	2D texture lookup with bias.	21
tex2Dgrad	2D texture lookup with a gradient.	21
tex2Dlod	2D texture lookup with LOD.	3
tex2Dproj	2D texture lookup with projective divide.	21
tex3D(s, t)	3D texture lookup.	11
tex3D(s, t, ddx, ddy)	3D texture lookup.	21
tex3Dbias	3D texture lookup with bias.	21
tex3Dgrad	3D texture lookup with a gradient.	21
tex3Dlod	3D texture lookup with LOD.	31
tex3Dproj	3D texture lookup with projective divide.	21
texCUBE(s, t)	Cube texture lookup.	11
texCUBE(s, t, ddx, ddy)	Cube texture lookup.	21
texCUBEbias	Cube texture lookup with bias.	21
texCUBEgrad	Cube texture lookup with a gradient.	21
texCUBElod	Cube texture lookup with LOD.	31
texCUBEproj	Cube texture lookup with projective divide.	21
transpose	Returns the transpose of the matrix m.	1
trunc	Truncates floating-point value(s) to integer value(s)	1