- Calculates the sine of an angle.
- angle
-
- The angle, using a full circle range of 0.0-1.0 measured clockwise (0.0 to the right).
The sin()
function calculates the sine of an angle.
Pico-8 uses an input range of 0.0 to 1.0 to represent the angle, a percentage of the unit circle. An angle of π (3.1415) radians (180 degrees) corresponds to a Pico-8 angle of 0.5.
Pico-8 measures the angle in a clockwise direction, with 0.0 to the right, 0.25 downward, and so on. This is inverted from the convention used in traditional geometry, though the inversion only affects sin()
, not cos().
The inversion is useful because Pico-8's screen (like most graphics engines) uses inverted y coordinates: an increase in y goes downward. Many uses of sin()
would need to be inverted anyway, so Pico-8 does it by convention.
(The clockwise direction of the angle is equivalent to going counterclockwise and negating sin()
. This is how it is described in the official documentation.)
Examples
for t=0,1,0.125 do print('sin('..t..') = '..sin(t)) end
prints:
sin(0) = 0 sin(0.125) = -0.7071 sin(0.25) = -1 sin(0.375) = -0.7071 sin(0.5) = 0 sin(0.625) = 0.7071 sin(0.75) = 1 sin(0.875) = 0.7071 sin(1) = 0