////////////////////////////////////////////////// INVERSE GONIO LOOKUP
| 336 | // INVERSE GONIO LOOKUP |
| 337 | // |
| 338 | float iasin(float f) |
| 339 | { |
| 340 | bool negative = (f < 0); |
| 341 | if (negative) |
| 342 | { |
| 343 | f = -f; |
| 344 | negative = true; |
| 345 | } |
| 346 | uint16_t value = round(f * 65535); |
| 347 | uint8_t lo = 0; |
| 348 | uint8_t hi = 90; |
| 349 | |
| 350 | while (hi - lo > 1) |
| 351 | { |
| 352 | uint8_t mi = (lo + hi) / 2; |
| 353 | if (sinTable16[mi] == value) |
| 354 | { |
| 355 | if (negative) return -mi; |
| 356 | return mi; |
| 357 | } |
| 358 | if (sinTable16[mi] < value) lo = mi; |
| 359 | else hi = mi; |
| 360 | } |
| 361 | float delta = value - sinTable16[lo]; |
| 362 | uint16_t range = sinTable16[hi] - sinTable16[lo]; |
| 363 | delta /= range; |
| 364 | if (negative) return -(lo + delta); |
| 365 | return (lo + delta); |
| 366 | } |
| 367 | |
| 368 | |
| 369 | float iacos(float f) |