方法/函数/库

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saturate	Saturate is a function that clamps it’s input between 0 and 1.
normalize	float normalize(float x) vec2 normalize(vec2 x) vec3 normalize(vec3 x) vec4 normalize(vec4 x) normalize() returns a vector with the same direction as its parameter, x, but with length 1.
dot	点乘。 float dot(float x, float y) float dot(vec2 x, vec2 y) float dot(vec3 x, vec3 y) float dot(vec4 x, vec4 y) dot() returns the dot product of two vectors, x and y. i.e., x[0]⋅y[0]+x[1]⋅y[1]+… If x and y are the same the square root of the dot product is equivalent to the length of the vector. The input parameters can be floating scalars or float vectors. In case of floating scalars the dot function is trivial and returns the product of x and y.
pow	pow(x, y) x的y次幂
rcp	rcp(x) = x的倒数(1/x) 借此来优化除法运算 shader低级优化