HLSL固有函数 【Intrinsic Functions (DirectX HLSL)】
原文：http://www.cppblog.com/lai3d/archive/2008/10/23/64889.html
放在blog上看起来方便,这个是MSDN上的，DirectX Documentation里也有
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。