I just stumbled into this issue with UEFN. The sin function in the material editor makes no sense at all. sin(pi/2) SHOULD be 1, and sin(pi) should be 0. In the material editor sin(pi/2)= -.4303004… and sin(pi)=0.77685…
This makes figuring out the math to do something like blending between two spritesheets that are offset to fake a seamless loop exceedingly difficult because the math doesn’t add up the way I’m expecting it to.
According to this thread the HLSL for sin and cos in the material editor is actually multiplying every input by tau before giving it to the sin and cos functions. Which I guess means to get what I want I should divide everything by tau before the sin and cos nodes, which seems like it’s adding unnecessary instructions.