# Concise Cg built-in function table

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The Cg function table:

## Functions

Function Description
abs( x ) Absolute value of x .
acos( x ) Arccos of x in range [0, pi], x in [-1, 1].
all( x ) true if all components of x != 0 - false otherwise.
any( x ) true if any component of x != 0 - false otherwise.
asin( x ) Arcsin of x in range [-pi/2,pi/2]; x in [-1, 1].
atan( x ) Arctan of x in range [-pi/2, pi/2].
atan2( y , x ) Arctan y/x in range [-pi,pi].
ceil( x ) Smallest integer not less than x .
clamp( x , a , b ) x clamped to the range [a,b]: a if x<a, b if x>b else returns x.
cos( x ) Cos of x.
cosh( x ) Hyperbolic cos of x .
cross( A , B ) Cross product of vectors A and B (A and B must be three-component).
ddx( a ) Partial derivative of a with respect to screen-space x coordinate
ddy( a ) Partial derivative of a with respect to screen-space y coordinate
debug(float4 x) If compiler DEBUG option is enabled, causes shader to halt with x copied to the COLOR output - otherwise it does nothing.
degrees( x ) convert radians to degrees.
determinant( x ) Determinant of matrix x.
distance( p1 , p2 ) Pythagorean distance between p1 and p2.
dot( A, B ) Dot product of A and B.
exp( x ) Exponential func: ex.
exp2( x ) Exponential function 2x.
faceforward( N, I, Ng ) N if dot( Ng , I ) < 0 otherwise (-N).
floor( x ) Largest integer not greater than x.
fmod( x , y ) Remainder of x/y (with the same sign as x). If y==0, result is undefined.
frac( x ) Fractional part of x.
frexp( x , out exp ) Splits x into normalized fraction in the interval [, 1), which is returned, and a power of 2, which is stored in exp . If x==0, both parts of the result are 0.
isfinite( x ) Returns true if x is finite.
isinf( x ) Returns true if x is infinite.
isnan( x ) Returns true if x is NaN.
ldexp( x , n ) x * 2n.
length( v ) Pythagorean length of vector.
lerp( a , b , f ) Linear interpolation: (1 - f)* a + b * f. f can be a vector of same length as a & b.
lit( NdotL , NdotH , m ) Computes lighting coefficients (m is the shininess). Returns: float4: .x=ambient (always 1), .y=diffuse (0 if N.L < 0), .z=specular (0 if N.L<0 or N.H<0); .w==1.0.
log( x ) Natural logarithm (x>0).
log2( x ) Log Base 2 (x>0).
log10( x ) Log Base 10 (x>0).
max( a , b ) Maximum of a and b .
min( a , b ) Minimum of a and b .
modf( x , out ip ) Splits x into int and frac parts (each with the same sign as x). Stores the int part in ip and returns the fractional part.
mul( M , N ) Matrix product of matrix M and matrix N: If M has size AxB, and N has size BxC, returns an AxC.
mul( M , v ) Product of matrix M and column vector v: If M has size AxB, and v is Bx1, returns an Ax1.
mul( v , M ) Product of row vector v and matrix M: If v is a 1xA and M is AxB, returns a 1xB.
noise( x ) Noise function. The returned value is between 0 and 1, and is always the same for a given input value.
normalize( v ) Normalize v.
pow( x , y ) xy
radians( x ) Converts degrees to radians.
reflect( I , N ) Computes reflection of I in a plane with surface normal N. (three-component vectors only).
refract( I , N , eta ) Computes refraction of I in a plane with surface normal N and refractive index eta. Returns (0,0,0) for total internal reflection. (three-component vectors only).
round( x ) Closest integer to x.
rsqrt( x ) Reciprocal square root of x (x>0).
saturate( x ) Clamps x to [0, 1].
sign( x ) Sign of x (returns -1, 0 or +1)
sin( x ) Sin of x.
sincos(float x , out s , out c ) s is set to sin(x), and c to cos(x).
sinh( x ) Hyperbolic sine of x.
smoothstep( min , max , x ) For values of x between min and max , returns a smoothly varying value that ranges from 0 at x==min to 1 at x==max. x is clamped to the range [min,max] and then returns 2*((x-min)/(max-min))3+3*((x-min)/(max-min))2
step( a , x ) 0 if x<a, 1 if x>=a
sqrt( x ) Square root of x (x>0)
tan( x ) Tan of x.
tanh( x ) Hyperbolic tan of x.
tex1D(sampler1D tex , float s ) 1D nonprojective texture lookup
tex1D(sampler1D tex , float s , float dsdx , float dsdy ) 1D nonprojective texture lookup with derivatives
tex1D(sampler1D tex , float2 sz ) 1D nonprojective depth compare texture lookup
tex1D(sampler1D tex , float2 sz , float dsdx , float dsdy ) 1D nonprojective depth compare texture lookup with derivatives
tex1Dproj(sampler1D tex , float2 sq ) 1D projective texture lookup
tex1Dproj(sampler1D tex , float3 szq ) 1D projective depth compare texture lookup
tex2D(sampler2D tex , float2 s ) 2D nonprojective texture lookup
tex2D(sampler2D tex , float2 s , float2 dsdx , float2 dsdy ) 2D nonprojective texture lookup with derivatives
tex2D(sampler2D tex , float3 sz ) 2D nonprojective depth compare texture lookup
tex2D(sampler2D tex , float3 sz , float2 dsdx , float2 dsdy ) 2D nonprojective depth compare texture lookup with derivatives
tex2Dproj(sampler2D tex , float3 sq ) 2D projective texture lookup
tex2Dproj(sampler2D tex , float4 szq ) 2D projective depth compare texture lookup
texRECT(samplerRECT tex , float2 s ) 2D nonprojective texture rectangle texture lookup (OpenGL)
texRECT(samplerRECT tex , float2 s , float2 dsdx , float2 dsdy ) 2D nonprojective texture rectangle texture lookup with derivatives (OpenGL)
texRECT(samplerRECT tex , float3 sz ) 2D nonprojective texture rectangle depth compare texture lookup (OpenGL)
texRECT(samplerRECT tex , float3 sz , float2 dsdx , float2 dsdy ) 2D nonprojective depth compare texture lookup with derivatives (OpenGL)
texRECTproj(samplerRECT tex , float3 sq ) 2D texture rectangle projective texture lookup (OpenGL)
texRECTproj(samplerRECT tex , float3 szq ) 2D texture rectangle projective depth compare texture lookup (OpenGL)
tex3D(sampler3D tex , float3 s ) 3D nonprojective texture lookup
tex3D(sampler3D tex , float3 s , float3 dsdx , float3 dsdy ) 3D nonprojective texture lookup with derivatives
tex3Dproj(sampler3D tex , float4 sq ) 3D projective texture lookup
texCUBE(samplerCUBE tex , float3 s ) Cubemap nonprojective texture lookup
texCUBE(samplerCUBE tex , float3 s , float3 dsdx , float3 dsdy ) Cubemap nonprojective texture lookup with derivatives
texCUBEproj(samplerCUBE tex , float4 sq ) Cube map projective texture lookup (ignores q)
transpose( M ) transpose of matrix M

NOTES:

• s indicates a one-, two-, or three-component texture coordinate.
• z indicates a depth comparison value for shadow map lookups.
• q indicates a perspective value, and is used to divide the texture coordinate ( s ) before the texture lookup is performed.

When you use the texture functions that allow specifying a depth comparison value, the associated texture unit must be configured for depth-compare texturing. Otherwise, no depth comparison will actually be performed.