return sin8( theta + 64);
}
+/// Fast 16-bit approximation of atan2(x).
+/// @returns atan2, value between 0 and 255
+LIB8STATIC uint8_t atan2_8(int16_t dy, int16_t dx)
+{
+ if (dy == 0)
+ {
+ if (dx >= 0)
+ return 0;
+ else
+ return 128;
+ }
+
+ int16_t abs_y = dy > 0 ? dy : -dy;
+ int8_t a;
+
+ if (dx >= 0)
+ a = 32 - (32 * (dx - abs_y) / (dx + abs_y));
+ else
+ a = 96 - (32 * (dx + abs_y) / (abs_y - dx));
+
+ if (dy < 0)
+ return -a; // negate if in quad III or IV
+ return a;
+}
+
///@}
#endif