coyote time

1 files changed, 59 insertions, 0 deletions

diff --git a/src/objs/specks.lua b/src/objs/specks.lua
new file mode 100644
index 0000000..a3a21c5
--- /dev/null
+++ b/src/objs/specks.lua
@@ -0,0 +1,59 @@
+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