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Speck_Sys = {}
Speck_Sys.__index = Speck_Sys
function Speck_Sys.new(texture)
local self = setmetatable({}, Speck_Sys)
self.data = {
size = 0,
pos = {},
vel = {},
lifetime = {},
lifetime_max = {},
scale_start = {},
scale_end = {}
}
self.scale_curve = lerp
self.scale_min = 1
self.scale_max = 1
self.scale_end_min = 1
self.scale_end_max = 1
self.texture = texture
end
function Speck_Sys:process(dt)
local data = self.data
for i = 1, data.size do
-- dead particles skip
if data.lifetime[i] <= 0 then
goto next_speck_process
end
data.pos[i].x = data.pos[i].x + data.vel[i].x * dt
data.pos[i].y = data.pos[i].y + data.vel[i].y * dt
data.lifetime[i] = data.lifetime[i] - dt
::next_speck_process::
end
end
function Speck_Sys:draw()
local scale_curve = self.scale_curve
local data = self.data
for i = 1, data.size do
local anim = data.lifetime[i] / data.lifetime_max[i]
local scale = scale_curve(self.scale_start, self.scale_end, anim)
lg.draw(
self.texture, data.pos[i].x, data.pos[i].y
)
end
end
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