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Speck_Sys = {}
Speck_Sys.__index = Speck_Sys
function speck_shape_rectangle(speck_sys)
local w = (speck_sys.spawn_width or 0) / 2
local h = (speck_sys.spawn_height or 0) / 2
return randf_range(-w, w), randf_range(-h, h)
end
function speck_shape_point(speck_sys)
return 0, 0
end
function speck_shape_circle(speck_sys)
local angle = randf_range(0, math.pi * 2)
local r = speck_sys.spawn_radius or 0
r = r * lmath.random()
return r*math.cos(angle), r*math.sin(angle)
end
function Speck_Sys.new()
local self = setmetatable({}, Speck_Sys)
self.data = {
size = 0,
pos = {},
vel = {},
alive = {},
lifetime = {},
lifetime_max = {},
scale_start = {},
scale_end = {}
}
self.free_ids = {}
self.free_ids_size = 0
self.spawn_shape = speck_shape_point
self.spawn_amount_min = 1
self.spawn_amount_max = 1
self.scale_curve = lerp
self.scale_start_min = 0.8
self.scale_start_max = 1.25
self.scale_end_min = 0
self.scale_end_max = 0
self.forcex = 0
self.forcey = 0
self.initial_velx = 0
self.initial_vely = 0
self.spread = 0
self.lifetime_min = 1
self.lifetime_max = 5
self.interval = 0.1
self.spawn_timer = self.interval
self.texture = get_tex("res/img/speck.png")
self.x = 0
self.y = 0
return self
end
function Speck_Sys:check_bounce(i)
if not self.bounce then
return false
end
local scn = get_current_scene()
assert(scn, "No scene set.")
return has_tile(
scn.tilemap,
to_tile_coords(self.data.pos[i].x, self.data.pos[i].y))
end
function Speck_Sys:spawn_particles()
local data = self.data
local amt = lmath.random(self.spawn_amount_min, self.spawn_amount_max)
for i = 1, amt do
local id
if self.free_ids_size > 0 then
id = self.free_ids[self.free_ids_size]
self.free_ids_size = self.free_ids_size - 1
else
self.data.size = self.data.size + 1
id = self.data.size
end
data.alive[id] = true
local offx, offy = self.spawn_shape(self)
data.pos[id] = { x = self.x + offx, y = self.y + offy }
data.vel[id] = { x = self.initial_velx, y = self.initial_vely }
local beta = self.spread * math.pi / 180
beta = beta / 2
beta = randf_range(-beta, beta)
local rvx = (data.vel[id].x * math.cos(beta))
- (data.vel[id].y * math.sin(beta))
local rvy = (data.vel[id].x * math.sin(beta))
+ (data.vel[id].y * math.cos(beta))
data.vel[id].x = rvx
data.vel[id].y = rvy
data.lifetime[id] = randf_range(
self.lifetime_min, self.lifetime_max)
data.lifetime_max[id] = data.lifetime[id]
data.scale_start[id] = randf_range(
self.scale_start_min, self.scale_start_max)
data.scale_end[id] = randf_range(
self.scale_end_min, self.scale_end_max)
end
end
function Speck_Sys:update(dt)
local data = self.data
-- particle spawning
self.spawn_timer = self.spawn_timer - dt
if self.spawn_timer <= 0 then
self.spawn_timer = self.interval
self:spawn_particles()
end
-- particles processing
for i = 1, data.size do
if not data.alive[i] then
goto next_speck_update
end
if data.lifetime[i] <= 0 then
data.alive[i] = false
self.free_ids_size = self.free_ids_size + 1
self.free_ids[self.free_ids_size] = i
goto next_speck_update
end
data.vel[i].x = data.vel[i].x + self.forcex * dt
data.vel[i].y = data.vel[i].y + self.forcey * dt
-- move and bounce
data.pos[i].x = data.pos[i].x + data.vel[i].x * dt
if self:check_bounce(i) then
data.vel[i].x = -data.vel[i].x
data.pos[i].x = data.pos[i].x + data.vel[i].x * dt
end
data.pos[i].y = data.pos[i].y + data.vel[i].y * dt
if self:check_bounce(i) then
data.vel[i].y = -data.vel[i].y
data.pos[i].y = data.pos[i].y + data.vel[i].y * dt
end
data.lifetime[i] = data.lifetime[i] - dt
::next_speck_update::
end
end
function Speck_Sys:draw()
local scale_curve = self.scale_curve
local data = self.data
for i = 1, data.size do
if not data.alive[i] then
goto next_speck_draw
end
local anim = 1 - data.lifetime[i] / data.lifetime_max[i]
local scale = scale_curve(data.scale_start[i], data.scale_end[i], anim)
local w, h = self.texture:getDimensions()
lg.draw(
self.texture, data.pos[i].x, data.pos[i].y, 0, scale, scale, w / 2, h / 2
)
::next_speck_draw::
end
end
register_comp("Speck_System", function(ent)
ent.speck_sys = Speck_Sys.new()
end)
function speck_update_sys(ent, dt)
ent.speck_sys.x = ent.x
ent.speck_sys.y = ent.y
ent.speck_sys:update(dt)
end
function speck_draw_sys(ent)
ent.speck_sys:draw()
end
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