static uint16_t last_timer = 0;
+inline int8_t times_inv_sqrt2(int8_t x)
+{
+ // 181/256 is pretty close to 1/sqrt(2)
+ // 0.70703125 0.707106781
+ // 1 too small for x=99 and x=198
+ // This ends up being a mult and discard lower 8 bits
+ return (x * 181) >> 8;
+}
static uint8_t move_unit(void)
{
if (mouse_report.y > 0) mouse_report.y = move_unit();
if (mouse_report.y < 0) mouse_report.y = move_unit() * -1;
- /* diagonal move [1/sqrt(2) = 0.7] */
+ /* diagonal move [1/sqrt(2)] */
if (mouse_report.x && mouse_report.y) {
- mouse_report.x *= 0.7;
- mouse_report.y *= 0.7;
+ mouse_report.x = times_inv_sqrt2(mouse_report.x);
+ mouse_report.y = times_inv_sqrt2(mouse_report.y);
}
if (mouse_report.v > 0) mouse_report.v = wheel_unit();