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add phys.apply

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This commit is contained in:
Donald Ball 2025-11-16 22:51:51 -05:00
parent fddb06ed8b
commit 9cdf032c39
4 changed files with 3880 additions and 0 deletions
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23
asteroids/phys.lua
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@ -1,3 +1,5 @@
local inspect = require('inspect')
local phys = {
tau = 2 * math.pi
}
@ -10,9 +12,30 @@ end
-- updates the actor's location by applying the passage of time
-- TODO spin
function phys.update(actor, dt)
assert(actor.speed >= 0)
local dv = actor.speed * dt
actor.x = actor.x + math.cos(actor.angle) * dv
actor.y = actor.y + math.sin(actor.angle) * dv
end
function phys.rotate(actor, angle)
actor.angle = (actor.angle + angle) % phys.tau
end
function phys.apply(actor, force)
assert(actor.speed >= 0)
assert(force.speed >= 0)
local ax = math.cos(actor.angle) * actor.speed
local ay = math.sin(actor.angle) * actor.speed
local fx = math.cos(force.angle) * force.speed
local fy = math.sin(force.angle) * force.speed
local x = ax + fx
local y = ay + fy
local speed = math.sqrt(x ^ 2 + y ^ 2)
local angle = math.atan(y, x) % phys.tau
actor.speed = speed
actor.angle = angle
end
return phys