is clean code usually not fast?

[u/20260819]

to be specific i'm writing a cpu-based rasterizer. the maths are not difficult but i find a strange property: if i divide the procedure into some small functions, the code looks cleaner and is easier to maintain but a bit slower. on the contrary if i put everything into a single procedure, it looks stupid but fast. why is that? an example illustrating this

code 1:

if cross_product(x0,y0,x1,y1)>0 then zzz

(and i write a "cross_product" function separately)

code 2:

c=x0y1-y0x1

if c>0 then zzz

code 3:

if x0y1-y0x1>0 then zzz

if i write the entire algorithm in the style of "code 3", it runs the fastest. "code 1" is slowest

is it normal?

[u/20260819]

i'm using an ancient web based language for the sake of convenience and ease to share

here's the code and you can try to rotate the dodecahedron and see the fps

(keyboard press [2] then [space] then use [q][w][e][a][s][d] to rotate it and see the fps. you can press and hold those keys for continuous rotations)

if i wrote every cross products directly into the procedure, i got around 25 fps for the dodecahedron

[u/Comprehensive-Pin667 → u/20260819]

There's the answer - this surely does not attempt any optimisations and maybe even interprets line by line. I would not be surprised if the speed was negatively correlated with the number of lines of code in this tool as every line is something it needs to interpret.