Math routines.
Below is a code example that uses the trigonometry functions to calculate the coordinate at which the second hand of a watch ends, using the seconds from a PblTm time.
int32_t atan2_lookup | ( | int16_t | y, |
int16_t | x | ||
) |
Look-up the arctangent of a given x, y pair The angle value is scaled linearly, such that a value of 0x10000 corresponds to 360 degrees or 2 PI radians.
int32_t cos_lookup | ( | int32_t | angle) |
Look-up the cosine of the given angle from a pre-computed table. This is equivalent to calling sin_lookup(angle + MAX_ANGLE / 4)
.
angle | The angle for which to compute the cosine. The angle value is scaled linearly, such that a value of 0x10000 corresponds to 360 degrees or 2 PI radians. |
int32_t sin_lookup | ( | int32_t | angle) |
Look-up the sine of the given angle from a pre-computed table.
angle | The angle for which to compute the cosine. The angle value is scaled linearly, such that a value of 0x10000 corresponds to 360 degrees or 2 PI radians. |
#define TRIG_MAX_ANGLE 0x10000 |
Angle value that corresponds to 360 degrees or 2 PI radians.
#define TRIG_MAX_RATIO 0xffff |
The largest value that can result from a call to sin_lookup or cos_lookup. For a code example, see the detailed description at the top of this chapter: Math.