ease8InOutApprox()

LIB8STATIC fract8 ease8InOutApprox

(

fract8

i

)

Fast, rough 8-bit ease-in/ease-out function.

Shaped approximately like ease8InOutCubic(), it's never off by more than a couple of percent from the actual cubic S-curve, and it executes more than twice as fast. Use when the cycles are more important than visual smoothness. Asm version takes around 7 cycles on AVR.

Definition at line 533 of file lib8tion.h.

{
    if( i < 64) {
        // start with slope 0.5
        i /= 2;
    } else if( i > (255 - 64)) {
        // end with slope 0.5
        i = 255 - i;
        i /= 2;
        i = 255 - i;
    } else {
        // in the middle, use slope 192/128 = 1.5
        i -= 64;
        i += (i / 2);
        i += 32;
    }
 
    return i;
}

References LIB8STATIC.