Merge branch 'main' of ssh://codeberg.org/the-gutter/gutshot

1 files changed, 283 insertions, 0 deletions

diff --git a/src/specks.lua b/src/specks.lua
new file mode 100644
index 0000000..a703d04
--- /dev/null
+++ b/src/specks.lua
@@ -0,0 +1,283 @@
+Speck_Sys = {}
+Speck_Sys.__index = Speck_Sys
+
+local SPAWN_FUNCTIONS = {
+  Rectangle = function (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,
+
+  Circle = function (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,
+
+  Point = function (speck_sys)
+    return 0, 0
+  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.bounce = false
+  self.gradient = "res/img/test_gradient.png"
+
+  self.spawn_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.texture_path = "res/img/speck.png"
+
+  self.x = 0
+  self.y = 0
+  self.spawn_timer = self.interval
+
+  self.oneshot = false
+  self.emitting = true
+  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)
+
+  local shape_func = SPAWN_FUNCTIONS[self.spawn_shape]
+  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 = shape_func(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 and self.emitting then
+    self.spawn_timer = self.interval
+
+    self:spawn_particles()
+    if self.oneshot then
+      self.emitting = false
+    end
+  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:is_empty()
+  if self.data.size == 0 then
+    return true
+  end
+  return self.free_ids_size == self.data.size
+end
+
+function Speck_Sys:draw()
+  local scale_curve = EASING_FUNCTIONS[self.scale_curve]
+  local data = self.data
+  local tex = get_tex(self.texture_path)
+
+  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 = tex:getDimensions()
+
+    local gradient = get_tex_data(self.gradient)
+    local sample_pos = math.floor((gradient:getWidth() - 1) * anim)
+    lg.setColor(gradient:getPixel(sample_pos, 0.5))
+
+    lg.draw(
+      tex, data.pos[i].x, data.pos[i].y, 0, scale, scale, w / 2, h / 2
+    )
+    lg.setColor(1, 1, 1, 1)
+    ::next_speck_draw::
+  end
+end
+
+
+function export_speck_sys(sys, filename)
+  local EXPORTED_ARGS = {
+    "spawn_shape",
+    "spawn_amount_min",
+    "spawn_amount_max",
+    "spawn_width",
+    "spawn_height",
+    "spawn_radius",
+    "scale_curve",
+    "scale_start_min",
+    "scale_start_max",
+    "scale_end_min",
+    "scale_end_max",
+    "forcex",
+    "forcey",
+    "initial_velx",
+    "initial_vely",
+    "spread",
+    "lifetime_min",
+    "lifetime_max",
+    "interval",
+    "texture_path",
+    "gradient",
+    "oneshot",
+    "bounce",
+  }
+  local exp = {}
+
+  for i, arg in ipairs(EXPORTED_ARGS) do
+    exp[arg] = sys[arg]
+  end
+  export_to_source(exp, filename)
+end
+
+local speck_bank = {}
+function load_specks_from(path)
+  path = path or "res/speck"
+  local files = lf.getDirectoryItems(path)
+
+  for _, file in ipairs(files) do
+    local filepath = path.."/"..file
+
+    if lf.getInfo(filepath).type == "directory" then
+      load_specks_from(filepath)
+    else
+      if is_filetype(filepath, {"speck.lua"}) then
+        local data = lf.load(filepath)()
+        speck_bank[filepath] = data
+      end
+    end
+  end
+end
+
+function load_speck_sys(filename)
+  local sys = Speck_Sys.new()
+  local loaded = speck_bank[filename]
+  for key, data in pairs(loaded) do
+    sys[key] = data
+  end
+  return sys
+end
+