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Calculating the angle formed by three points in PICO-8
-- ❎ changes selected point
-- direction keys move point
function _init()
a = {x=20,y=20}
b = {x=80,y=80}
c = {x=40,y=60}
pts = {a,b,c}
sel = 1
end
function _update()
if (btn(⬆️) and pts[sel].y > 0) pts[sel].y -= 1
if (btn(⬇️) and pts[sel].y < 127) pts[sel].y += 1
if (btn(⬅️) and pts[sel].x > 0) pts[sel].x -= 1
if (btn(➡️) and pts[sel].x < 127) pts[sel].x += 1
if (btnp(❎)) sel = ((sel + 1) % #pts) + 1
end
function _draw()
cls()
line(a.x, a.y, b.x, b.y, 13)
line(b.x, b.y, c.x, c.y, 14)
circfill(a.x, a.y, 2, 8)
circfill(b.x, b.y, 2, 11)
circfill(c.x, c.y, 2, 12)
circ(pts[sel].x, pts[sel].y, 4, 7)
ab = atan2(b.x-a.x, b.y-a.y)
bc = atan2(b.x-c.x, b.y-c.y)
angle = ab-bc
print('\f8a\fbb\f6='..ab, 0, 128-18, 6)
print('\fcc\fbb\f6='..bc, 0, 128-12, 6)
print('angle='..angle, 0, 128-6, 6)
end
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