Add Animation

animation.lua

@@ -0,0 +1,65 @@
+local Object = require "lib/classic"
+
+---@class Frame
+---@field sprite number The index of the sprite in the atlas.
+---@field duration? number The duration (in seconds) of this frame.
+---@field atlas? Atlas The sprite atlas this frame is drawn from.
+
+---@class Animation
+---A timed sequence of sprites.
+local Animation = Object:extend()
+
+---Creates a new animation.
+---@param frames Frame[] A list of frames.
+---@param duration? number The default duration to use for this animation. Defaults to 15 FPS.
+---@param atlas? Atlas The default atlas to use for this animation.
+function Animation:new(frames, duration, atlas)
+  local default_duration = duration or (1.0 / 15.0)
+
+  ---The list of frames.
+  self.frames = {}
+
+  local total_duration = 0
+
+  for idx, frame in ipairs(frames) do
+    total_duration = total_duration + (frame.duration or default_duration)
+
+    self.frames[idx] = {
+      sprite = frame.sprite,
+      duration = frame.duration or duration,
+      atlas = frame.atlas or atlas or error("Missing default atlas"),
+    }
+  end
+
+  ---The total duration of this animation.
+  self.duration = total_duration
+end
+
+---Creates a new animation from the sprites between start and end indices, plus an atlas.
+---@param atlas Atlas The atlas that the sprites are from.
+---@param start_idx number The first sprite index in the animation.
+---@param end_idx number The last sprite index in the animation.
+---@param duration? number The duration of each frame. Defaults to 15 FPS.
+---@return Animation
+function Animation:new_spanned(atlas, start_idx, end_idx, duration)
+  local duration = duration or (1.0 / 15.0)
+  local frames = {}
+
+  for sprite = start_idx, end_idx do
+    frames[#frames + 1] = { sprite = sprite, atlas = atlas, duration = duration }
+  end
+
+  return Animation(frames)
+end
+
+---Draws a frame of this animation.
+---@param index number The index of the frame.
+---@param x number The X position to draw at.
+---@param y number The Y position to draw at.
+function Animation:draw(index, x, y)
+  local frame = self.frames[index]
+  local mesh = frame.atlas.meshes[frame.sprite]
+  love.graphics.draw(mesh, x, y)
+end
+
+return Animation

atlas.lua

@@ -1,6 +1,7 @@
 local Math = require "math"
 local Object = require "lib/classic"
 
+---@class Atlas
 ---A spriteset laid out on a regular grid.
 local Atlas = Object:extend()
 

main.lua

@@ -1,3 +1,4 @@
+local Animation = require "animation"
 local Atlas = require "atlas"
 local Font = require "font"
 local MultiMenu = require "multimenu"
@@ -28,14 +29,17 @@ function love.load()
   BlockyFont = Font(blockyFont, 8, 8, blockFontChars)
   Menu = MultiMenu(BlockyFont, { "Fight", "Use", "Pkmn", "Flee" })
 
-  local leafRanger = love.graphics.newImage("assets/leaf-ranger.png")
+  local leafRangerSprites = love.graphics.newImage("assets/leaf-ranger.png")
+  local leafRangerAtlas = Atlas(leafRangerSprites, 288, 128)
+
+  LeafRangerAnimations = {
+    idle = Animation:new_spanned(leafRangerAtlas, 1, 12),
+  }
 
   LeafRanger = {
-    atlas = Atlas(leafRanger, 288, 128),
+    animation = LeafRangerAnimations.idle,
     step = 0,
-    duration = 1.0 / 15.0,
     frame = 1,
-    max = 12,
   }
 end
 
@@ -45,7 +49,7 @@ function love.draw()
   Menu:draw()
   BlockyFont:draw("Hello, world!")
 
-  love.graphics.draw(LeafRanger.atlas.meshes[LeafRanger.frame])
+  LeafRanger.animation:draw(LeafRanger.frame, 0, 0)
 
   push:finish()
 end
@@ -53,11 +57,11 @@ end
 function love.update(dt)
   LeafRanger.step = LeafRanger.step + dt
 
-  if LeafRanger.step > LeafRanger.duration then
+  if LeafRanger.step > LeafRanger.animation.frames[LeafRanger.frame].duration then
     LeafRanger.step = 0
     LeafRanger.frame = LeafRanger.frame + 1
-    if LeafRanger.frame > LeafRanger.max then
-    	LeafRanger.frame = 1
+    if LeafRanger.frame > #LeafRanger.animation.frames then
+      LeafRanger.frame = 1
     end
   end
 end