sin(x): Sine of the input x (in radians).
cos(x): Cosine of the input x (in radians).
tan(x): Tangent of the input x.
asin(x): Arc sine of the input x.
acos(x): Arc cosine of the input x.
atan(x): Arc tangent of the input x.
atan2(y, x): Arc tangent of y/x, handling the correct quadrant.
exp(x): Exponential function e^x.
log(x): Natural logarithm of x.
log2(x): Logarithm base 2 of x.
pow(x, y): x raised to the power of y.
sqrt(x): Square root of x.
rsqrt(x): Reciprocal square root of x.
abs(x): Absolute value of x.
sign(x): Returns the sign of x (1 for positive, -1 for negative).
floor(x): Floors x to the nearest integer.
ceil(x): Ceils x to the nearest integer.
round(x): Rounds x to the nearest integer.
frac(x): Fractional part of x (i.e., x - floor(x)).
dot(x, y): Dot product of two vectors x and y.
cross(x, y): Cross product of two vectors x and y.
length(x): Length (magnitude) of vector x.
normalize(x): Normalizes the vector x (scales it to have a magnitude of 1).
reflect(i, n): Reflect vector i around the normal vector n.
refract(i, n, eta): Refraction of vector i through a surface with normal n and refraction index eta.
lerp(a, b, t): Linear interpolation between a and b based on t.
clamp(x, min, max): Clamps x between the min and max values.
min(x, y): Returns the minimum of x and y.
max(x, y): Returns the maximum of x and y.
if(condition, a, b): If the condition is true, returns a; otherwise, returns b.
step(edge, x): Compares x to edge and returns 0 if x < edge or 1 if x >= edge.
smoothstep(edge0, edge1, x): Smooth interpolation between 0 and 1 based on x, clamped between edge0 and edge1.
fmod(x, y): Floating-point modulus of x by y.
mix(a, b, t): Similar to lerp, but can also take in more types of data.
exp2(x): Exponential function with base 2.
step(edge, x): Returns 0.0 if x < edge, otherwise 1.0.
If you're working with custom texture sampling, you can use the following functions:
Texture2DSample(Tex, TexSampler, UV): Samples a 2D texture at the given UV coordinates.
fresnel(x): Calculates the Fresnel effect (for reflection effects).
dFdx(x): Derivative of x in the x direction (used for things like normal maps).
dFdy(x): Derivative of x in the y direction.