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.

NameSyntaxDescriptionabsabs(x)Absolute value (per component).acosacos(x)Returns the arccosine of each component of x.allall(x)Test if all components of x are nonzero.anyany(x)Test if any component of x is nonzero.asfloatasfloat(x)Convert the input type to a float.asinasin(x)Returns the arcsine of each component of x.asintasint(x)Convert the input type to an integer.asuintasuint(x)Convert the input type to an unsigned integer.atanatan(x)Returns the arctangent of x.atan2atan2(y, x)Returns the arctangent of of two values (x,y).ceilceil(x)Returns the smallest integer which is greater than or equal to x.clampclamp(x, min, max)Clamps x to the range [min, max].clipclip(x)Discards the current pixel, if any component of x is less than zero.coscos(x)Returns the cosine of x.coshcosh(x)Returns the hyperbolic cosine of x.crosscross(x, y)Returns the cross product of two 3D vectors.D3DCOLORtoUBYTE4D3DCOLORtoUBYTE4(x)Swizzles and scales components of the 4D vector x to compensate for the lack of UBYTE4 support in some hardware.ddxddx(x)Returns the partial derivative of x with respect to the screen-space x-coordinate.ddyddy(x)Returns the partial derivative of x with respect to the screen-space y-coordinate.degreesdegrees(x)Converts x from radians to degrees.determinantdeterminant(m)Returns the determinant of the square matrix m.distancedistance(x, y)Returns the distance between two points.dotdot(x, y)Returns the dot product of two vectors.expexp(x)Returns the base-e exponent.exp2exp2(x)Base 2 exponent (per component).faceforwardfaceforward(n, i, ng)Returns -n * sign(•(i, ng)).floorfloor(x)Returns the greatest integer which is less than or equal to x.fmodfmod(x, y)Returns the floating point remainder of x/y.fracfrac(x)Returns the fractional part of x.frexpfrexp(x, exp)Returns the mantissa and exponent of x.fwidthfwidth(x)Returns abs(ddx(x)) + abs(ddy(x))GetRenderTargetSampleCountGetRenderTargetSampleCount()Returns the number of render-target samples.GetRenderTargetSamplePositionGetRenderTargetSamplePosition(x)Returns a sample position (x,y) for a given sample index.isfiniteisfinite(x)Returns true if x is finite, false otherwise.isinfisinf(x)Returns true if x is +INF or -INF, false otherwise.isnanisnan(x)Returns true if x is NAN or QNAN, false otherwise.ldexpldexp(x, exp)Returns x * 2explengthlength(v)Returns the length of the vector v.lerplerp(x, y, s)Returns x + s(y - x).litlit(n • l, n • h, m)Returns a lighting vector (ambient, diffuse, specular, 1)loglog(x)Returns the base-e logarithm of x.log10log10(x)Returns the base-10 logarithm of x.log2log2(x)Returns the base-2 logarithm of x.maxmax(x, y)Selects the greater of x and y.minmin(x, y)Selects the lesser of x and y.modfmodf(x, out ip)Splits the value x into fractional and integer parts.mulmul(x, y)Performs matrix multiplication using x and y.noisenoise(x)Generates a random value using the Perlin-noise algorithm.normalizenormalize(x)Returns a normalized vector.powpow(x, y)Returns x^y.radiansradians(x)Converts x from degrees to radians.reflectreflect(i, n)Returns a reflection vector.refractrefract(i, n, R)Returns the refraction vector.roundround(x)Rounds x to the nearest integerrsqrtrsqrt(x)Returns 1 / sqrt(x)saturatesaturate(x)Clamps x to the range [0, 1]signsign(x)Computes the sign of x.sinsin(x)Returns the sine of xsincossincos(x, out s, out c)Returns the sine and cosine of x.sinhsinh(x)Returns the hyperbolic sine of xsmoothstepsmoothstep(min, max, x)Returns a smooth Hermite interpolation between 0 and 1.sqrtsqrt(x)Square root (per component)stepstep(a, x)Returns (x >= a) ? 1 : 0tantan(x)Returns the tangent of xtanhtanh(x)Returns the hyperbolic tangent of xtex1Dtex1D(s, t)1D texture lookup.tex1Dbiastex1Dbias(s, t)1D texture lookup with bias.tex1Dgradtex1Dgrad(s, t, ddx, ddy)1D texture lookup with a gradient.tex1Dlodtex1Dlod(s, t)1D texture lookup with LOD.tex1Dprojtex1Dproj(s, t)1D texture lookup with projective divide.tex2Dtex2D(s, t)2D texture lookup.tex2Dbiastex2Dbias(s, t)2D texture lookup with bias.tex2Dgradtex2Dgrad(s, t, ddx, ddy)2D texture lookup with a gradient.tex2Dlodtex2Dlod(s, t)2D texture lookup with LOD.tex2Dprojtex2Dproj(s, t)2D texture lookup with projective divide.tex3Dtex3D(s, t)3D texture lookup.tex3Dbiastex3Dbias(s, t)3D texture lookup with bias.tex3Dgradtex3Dgrad(s, t, ddx, ddy)3D texture lookup with a gradient.tex3Dlodtex3Dlod(s, t)3D texture lookup with LOD.tex3Dprojtex3Dproj(s, t)3D texture lookup with projective divide.texCUBEtexCUBE(s, t)Cube texture lookup.texCUBEbiastexCUBEbias(s, t)Cube texture lookup with bias.texCUBEgradtexCUBEgrad(s, t, ddx, ddy)Cube texture lookup with a gradient.texCUBElodtex3Dlod(s, t)Cube texture lookup with LOD.texCUBEprojtexCUBEproj(s, t)Cube texture lookup with projective divide.transposetranspose(m)Returns the transpose of the matrix m.trunctrunc(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.

NameDescriptionMinimum shader modelabsAbsolute value (per component).11acosReturns the arccosine of each component of x.11allTest if all components of x are nonzero.11AllMemoryBarrierBlocks execution of all threads in a group until all memory accesses have been completed.5AllMemoryBarrierWithGroupSyncBlocks execution of all threads in a group until all memory accesses have been completed and all threads in the group have reached this call.5anyTest if any component of x is nonzero.11asdoubleReinterprets a cast value into a double.5asfloatConvert the input type to a float.4asinReturns the arcsine of each component of x.11asintConvert the input type to an integer.4asuintReinterprets the bit pattern of a 64-bit type to a uint.5asuintConvert the input type to an unsigned integer.4atanReturns the arctangent of x.11atan2Returns the arctangent of of two values (x,y).11ceilReturns the smallest integer which is greater than or equal to x.11clampClamps x to the range [min, max].11clipDiscards the current pixel, if any component of x is less than zero.11cosReturns the cosine of x.11coshReturns the hyperbolic cosine of x.11countbitsCounts the number of bits (per component) in the input integer.5crossReturns the cross product of two 3D vectors.11D3DCOLORtoUBYTE4Swizzles and scales components of the 4D vector xto compensate for the lack of UBYTE4 support in some hardware.11ddxReturns the partial derivative of x with respect to the screen-space x-coordinate.21ddx_coarseComputes a low precision partial derivative with respect to the screen-space x-coordinate.5ddx_fineComputes a high precision partial derivative with respect to the screen-space x-coordinate.5ddyReturns the partial derivative of x with respect to the screen-space y-coordinate.21ddy_coarseComputes a low precision partial derivative with respect to the screen-space y-coordinate.5ddy_fineComputes a high precision partial derivative with respect to the screen-space y-coordinate.5degreesConverts x from radians to degrees.11determinantReturns the determinant of the square matrix m.11DeviceMemoryBarrierBlocks execution of all threads in a group until all device memory accesses have been completed.5DeviceMemoryBarrierWithGroupSyncBlocks 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.5distanceReturns the distance between two points.11dotReturns the dot product of two vectors.1dstCalculates a distance vector.5EvaluateAttributeAtCentroidEvaluates at the pixel centroid.5EvaluateAttributeAtSampleEvaluates at the indexed sample location.5EvaluateAttributeSnappedEvaluates at the pixel centroid with an offset.5expReturns the base-e exponent.11exp2Base 2 exponent (per component).11f16tof32Converts the float16 stored in the low-half of the uint to a float.5f32tof16Converts an input into a float16 type.5faceforwardReturns -n * sign(dot(i, ng)).11firstbithighGets the location of the first set bit starting from the highest order bit and working downward, per component.5firstbitlowReturns the location of the first set bit starting from the lowest order bit and working upward, per component.5floorReturns the greatest integer which is less than or equal to x.11fmodReturns the floating point remainder of x/y.11fracReturns the fractional part of x.11frexpReturns the mantissa and exponent of x.21fwidthReturns abs(ddx(x)) + abs(ddy(x))21GetRenderTargetSampleCountReturns the number of render-target samples.4GetRenderTargetSamplePositionReturns a sample position (x,y) for a given sample index.4GroupMemoryBarrierBlocks execution of all threads in a group until all group shared accesses have been completed.5GroupMemoryBarrierWithGroupSyncBlocks 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.5InterlockedAddPerforms a guaranteed atomic add of value to the dest resource variable.5InterlockedAndPerforms a guaranteed atomic and.5InterlockedCompareExchangeAtomically compares the input to the comparison value and exchanges the result.5InterlockedCompareStoreAtomically compares the input to the comparison value.5InterlockedExchangeAssigns value to dest and returns the original value.5InterlockedMaxPerforms a guaranteed atomic max.5InterlockedMinPerforms a guaranteed atomic min.5InterlockedOrPerforms a guaranteed atomic or.5InterlockedXorPerforms a guaranteed atomic xor.5isfiniteReturns true if x is finite, false otherwise.11isinfReturns true if x is +INF or -INF, false otherwise.11isnanReturns true if x is NAN or QNAN, false otherwise.11ldexpReturns x * 2exp11lengthReturns the length of the vector v.11lerpReturns x + s(y - x).11litReturns a lighting vector (ambient, diffuse, specular, 1)11logReturns the base-e logarithm of x.11log10Returns the base-10 logarithm of x.11log2Returns the base-2 logarithm of x.11madPerforms an arithmetic multiply/add operation on three values.5maxSelects the greater of x and y.11minSelects the lesser of x and y.11modfSplits the value x into fractional and integer parts.11mulPerforms matrix multiplication using x and y.1noiseGenerates a random value using the Perlin-noise algorithm.11normalizeReturns a normalized vector.11powReturns xy.11Process2DQuadTessFactorsAvgGenerates the corrected tessellation factors for a quad patch.5Process2DQuadTessFactorsMaxGenerates the corrected tessellation factors for a quad patch.5Process2DQuadTessFactorsMinGenerates the corrected tessellation factors for a quad patch.5ProcessIsolineTessFactorsGenerates the rounded tessellation factors for an isoline.5ProcessQuadTessFactorsAvgGenerates the corrected tessellation factors for a quad patch.5ProcessQuadTessFactorsMaxGenerates the corrected tessellation factors for a quad patch.5ProcessQuadTessFactorsMinGenerates the corrected tessellation factors for a quad patch.5ProcessTriTessFactorsAvgGenerates the corrected tessellation factors for a tri patch.5ProcessTriTessFactorsMaxGenerates the corrected tessellation factors for a tri patch.5ProcessTriTessFactorsMinGenerates the corrected tessellation factors for a tri patch.5radiansConverts x from degrees to radians.1rcpCalculates a fast, approximate, per-component reciprocal.5reflectReturns a reflection vector.1refractReturns the refraction vector.11reversebitsReverses the order of the bits, per component.5roundRounds x to the nearest integer11rsqrtReturns 1 / sqrt(x)11saturateClamps x to the range [0, 1]1signComputes the sign of x.11sinReturns the sine of x11sincosReturns the sine and cosine of x.11sinhReturns the hyperbolic sine of x11smoothstepReturns a smooth Hermite interpolation between 0 and 1.11sqrtSquare root (per component)11stepReturns (x >= a) ? 1 : 011tanReturns the tangent of x11tanhReturns the hyperbolic tangent of x11tex1D(s, t)1D texture lookup.1tex1D(s, t, ddx, ddy)1D texture lookup.21tex1Dbias1D texture lookup with bias.21tex1Dgrad1D texture lookup with a gradient.21tex1Dlod1D texture lookup with LOD.31tex1Dproj1D texture lookup with projective divide.21tex2D(s, t)2D texture lookup.11tex2D(s, t, ddx, ddy)2D texture lookup.21tex2Dbias2D texture lookup with bias.21tex2Dgrad2D texture lookup with a gradient.21tex2Dlod2D texture lookup with LOD.3tex2Dproj2D texture lookup with projective divide.21tex3D(s, t)3D texture lookup.11tex3D(s, t, ddx, ddy)3D texture lookup.21tex3Dbias3D texture lookup with bias.21tex3Dgrad3D texture lookup with a gradient.21tex3Dlod3D texture lookup with LOD.31tex3Dproj3D texture lookup with projective divide.21texCUBE(s, t)Cube texture lookup.11texCUBE(s, t, ddx, ddy)Cube texture lookup.21texCUBEbiasCube texture lookup with bias.21texCUBEgradCube texture lookup with a gradient.21texCUBElodCube texture lookup with LOD.31texCUBEprojCube texture lookup with projective divide.21transposeReturns the transpose of the matrix m.1truncTruncates floating-point value(s) to integer value(s)1