CG Shader常用函数

为了方便自己记忆，将常用的CG函数写于此

转载于 http://www.cppblog.com/lai3d/archive/2008/10/23/64889.html

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)