From a81b080cc830d3073fda40ec777ab24f72cacfb9 Mon Sep 17 00:00:00 2001
From: Elizabeth Hunt <me@liz.coffee>
Date: Sat, 25 Apr 2026 20:42:30 -0700
Subject: Getting a sword slashing animation working

---
 dyl.lua    | 248 +++++++++++++++++++++++++++++++++++++++++--------------------
 dyl.p8     |  26 +++----
 entity.lua |  24 ++++--
 util.lua   | 116 ++++++++++++++++++-----------
 world.lua  |  27 ++++++-
 5 files changed, 297 insertions(+), 144 deletions(-)

diff --git a/dyl.lua b/dyl.lua
index 6c2a012..6a337cd 100644
--- a/dyl.lua
+++ b/dyl.lua
@@ -1,64 +1,139 @@
+_slashing_timer_sec = 0.12
+function spawn_slashing_particle(e)
+    slash_animation = entity()
+    _slash_animation_distance = 3
+    function slash_animation:transition_state()
+        -- TODO: Find a better place to put this lol. This has nothing to do with state
+        -- transitions
+        slash_animation:equipped_from(e, _slash_animation_distance)
+    end
+    return slash_animation:b_type(Entities.Enemy)
+        :b_line_of_sight(e.line_of_sight)
+        :b_position(vec2(e.position))
+        :b_sprite_position(vec2(position))
+        :b_render_order(-1)
+        :b_live_for(_slashing_timer_sec)
+        :b_add_state(
+            States.Active, {
+                animation = {
+                    pos_y = { sequence = { 115, 116, 117 }, dt = _slashing_timer_sec / 3, reflect = vec2(true, true) },
+                    neg_y = { sequence = { 115, 116, 117 }, dt = _slashing_timer_sec / 3 },
+                    pos_x = { sequence = { 112, 113, 114 }, dt = _slashing_timer_sec / 3 },
+                    neg_x = { sequence = { 112, 113, 114 }, dt = _slashing_timer_sec / 3, reflect = vec2(true, false) }
+                }
+            }
+        )
+        :b_state(States.Active)
+        :build()
+end
+
+enemy = entity()
+function enemy:transition_state()
+end
+enemy:b_type(Entities.Enemy)
+    :b_position(vec2(30, 40))
+    :b_sprite_position(vec2(30, 30))
+    :b_line_of_sight(vec2(1, 0))
+    :b_render_order(1)
+    :b_collidable()
+    :b_add_state(
+        States.Idle, {
+            animation = {
+                pos_y = { sequence = { 32, 33 }, dt = 1 },
+                neg_y = { sequence = { 32, 33 }, dt = 1 },
+                pos_x = { sequence = { 32, 33 }, dt = 1 },
+                neg_x = { sequence = { 32, 33 }, dt = 1, reflect = vec2(true, false) }
+            }
+        }
+    )
+    :b_add_state(
+        States.Walk, {
+            animation = {
+                pos_x = { sequence = { 32, 34 }, dt = 0.20 },
+                neg_x = { sequence = { 32, 34 }, dt = 0.20, reflect = vec2(true, false) },
+                pos_y = { sequence = { 32, 34 }, dt = 0.20 },
+                neg_y = { sequence = { 32, 34 }, dt = 0.20 }
+            }
+        }
+    )
+    :b_state(States.Walk)
+    :b_equipped({ sword })
+    :build()
+
+
 bow = entity()
 function bow:transition_state()
 end
-bow
-    :b_type(Entities.Bow)
+bow:b_type(Entities.Bow)
     :b_position(vec2(0, 0))
     :b_sprite_position(vec2(0, 0))
     :b_line_of_sight(vec2(1, 0))
     :b_render_order(1)
     :b_collidable()
-    :b_add_state(States.Equipped, {
-      animation={
-        pos_y = { sequence = { 96 }, dt = 1, reflect = vec2(false, true) },
-        neg_y = { sequence = { 96 }, dt = 1 },
-        pos_x = { sequence = { 80 }, dt = 1 },
-        neg_x = { sequence = { 80 }, dt = 1, reflect = vec2(true, false) }
-      }
-    })
-    :b_add_state(States.Drawn, {
-      animation={
-        pos_y = { sequence = { 81 }, dt = 1, reflect = vec2(false, true) },
-        neg_y = { sequence = { 81 }, dt = 1 },
-        pos_x = { sequence = { 81 }, dt = 1 },
-        neg_x = { sequence = { 81 }, dt = 1, reflect = vec2(true, false) }
-      }
-    })
-    :b_add_state(States.Drawing, {
-      animation = bow.states[States.Equipped]
-    })
+    :b_add_state(
+        States.Equipped, {
+            animation = {
+                pos_y = { sequence = { 96 }, dt = 1, reflect = vec2(false, true) },
+                neg_y = { sequence = { 96 }, dt = 1 },
+                pos_x = { sequence = { 80 }, dt = 1 },
+                neg_x = { sequence = { 80 }, dt = 1, reflect = vec2(true, false) }
+            }
+        }
+    )
+    :b_add_state(
+        States.Drawn, {
+            animation = {
+                pos_y = { sequence = { 81 }, dt = 1, reflect = vec2(false, true) },
+                neg_y = { sequence = { 81 }, dt = 1 },
+                pos_x = { sequence = { 81 }, dt = 1 },
+                neg_x = { sequence = { 81 }, dt = 1, reflect = vec2(true, false) }
+            }
+        }
+    )
+    :b_add_state(
+        States.Drawing, {
+            animation = bow.states[States.Equipped]
+        }
+    )
     :b_state(States.Equipped)
     :build()
 
 sword = entity()
-_slashing_timer_ms = 500
 function sword:transition_state()
-    if(btn(5)) then self:transition_to(States.Slashing) 
-    elseif self.state == States.Slashing and self.state_stopwatch > _slashing_timer_ms then self:transition_to(States.Equipped) end
+    if button_just_pressed(5) and self.state == States.Equipped then
+        self:transition_to(States.Slashing)
+        spawn_slashing_particle(self)
+    elseif self.state == States.Slashing and self.state_stopwatch > _slashing_timer_sec then
+        self:transition_to(States.Equipped)
+    end
 end
 sword
     :b_type(Entities.Sword)
     :b_line_of_sight(vec2(1, 0))
     :b_position(vec2(0, 0))
     :b_sprite_position(vec2(0, 0))
-    :b_render_order(1)
+    :b_render_order(0)
     :b_collidable()
-    :b_add_state(States.Equipped, {
-      animation={
-        pos_y = { sequence = { 82 }, dt = 1, reflect = vec2(false, true) },
-        neg_y = { sequence = { 82 }, dt = 1, reflect = vec2(true, false)},
-        pos_x = { sequence = { 82 }, dt = 1 },
-        neg_x = { sequence = { 82 }, dt = 1, reflect = vec2(true, false) }
-      }
-    })
-    :b_add_state(States.Slashing, {
-      animation={
-        pos_y = { sequence = { 82, 82+16 }, dt = 1, reflect = vec2(false, true) },
-        neg_y = { sequence = { 82, 82+16 }, dt = 1, reflect = vec2(true, false)},
-        pos_x = { sequence = { 82, 82+16 }, dt = 1 },
-        neg_x = { sequence = { 82, 82+16 }, dt = 1, reflect = vec2(true, false) }
-      }
-    })
+    :b_add_state(
+        States.Equipped, {
+            animation = {
+                pos_y = { sequence = { 99 }, dt = 1, reflect = vec2(false, true) },
+                neg_y = { sequence = { 99 }, dt = 1, reflect = vec2(true, false) },
+                pos_x = { sequence = { 98 }, dt = 1 },
+                neg_x = { sequence = { 98 }, dt = 1, reflect = vec2(true, false) }
+            }
+        }
+    )
+    :b_add_state(
+        States.Slashing, {
+            animation = {
+                pos_y = { sequence = { 82, 98 }, dt = _slashing_timer_sec / 2, reflect = vec2(false, true) },
+                neg_y = { sequence = { 82, 98 }, dt = _slashing_timer_sec / 2, reflect = vec2(true, false) },
+                pos_x = { sequence = { 82, 99 }, dt = _slashing_timer_sec / 2, reflect = vec2(false, false)},
+                neg_x = { sequence = { 82, 99 }, dt = _slashing_timer_sec / 2, reflect = vec2(true, false) }
+            }
+        }
+    )
     :b_state(States.Equipped)
     :build()
 
@@ -70,61 +145,74 @@ function player:transition_state()
         self:transition_to(States.Walk)
     end
 end
-player:b_type(Entities.Player)
+player
+    :b_type(Entities.Player)
     :b_line_of_sight(vec2(1, 0))
-    :b_render_order(0)
+    :b_render_order(2)
     :b_collidable()
-    :b_position(vec2(30,30))
-    :b_sprite_position(vec2(30,30))
-    :b_add_state(States.Idle, {
-      animation = {
-        pos_y = { sequence = { 3, 19 }, dt = 1 },
-        neg_y = { sequence = { 6, 22 }, dt = 1 },
-        pos_x = { sequence = { 0, 1 }, dt = 1 },
-        neg_x = { sequence = { 0, 1 }, dt = 1, reflect = vec2(true, false) }
-      }
-    })
-    :b_add_state(States.Walk, {
-      animation = {
-        pos_x = { sequence = { 2, 0 }, dt = 0.20 },
-        neg_x = { sequence = { 2, 0 }, dt = 0.20, reflect = vec2(true, false) },
-        pos_y = { sequence = { 4, 5 }, dt = 0.20 },
-        neg_y = { sequence = { 7, 8 }, dt = 0.20 }
-      }
-    })
-    :b_state("idle")
+    :b_position(vec2(30, 30))
+    :b_sprite_position(vec2(30, 30))
+    :b_add_state(
+        States.Idle, {
+            animation = {
+                pos_y = { sequence = { 3, 19 }, dt = 1 },
+                neg_y = { sequence = { 6, 22 }, dt = 1 },
+                pos_x = { sequence = { 0, 1 }, dt = 1 },
+                neg_x = { sequence = { 0, 1 }, dt = 1, reflect = vec2(true, false) }
+            }
+        }
+    )
+    :b_add_state(
+        States.Walk, {
+            animation = {
+                pos_x = { sequence = { 2, 0 }, dt = 0.20 },
+                neg_x = { sequence = { 2, 0 }, dt = 0.20, reflect = vec2(true, false) },
+                pos_y = { sequence = { 4, 5 }, dt = 0.20 },
+                neg_y = { sequence = { 7, 8 }, dt = 0.20 }
+            }
+        }
+    )
+    :b_state(States.Idle)
     :b_equipped({ sword })
     :build()
 
 _walk_speed = 35 -- powerup increase?
 function handle_input()
-  dpos = vec2(0, 0)
-  if btn(0) then dpos.x -= 1 end
-  if btn(1) then dpos.x += 1 end
-  if btn(3) then dpos.y += 1 end
-  if btn(2) then dpos.y -= 1 end
+    dpos = vec2(0, 0)
+    if btn(0) then dpos.x -= 1 end
+    if btn(1) then dpos.x += 1 end
+    if btn(3) then dpos.y += 1 end
+    if btn(2) then dpos.y -= 1 end
 
-  player.velocity = dpos:normal() * _walk_speed
+    player.velocity = dpos:normal() * _walk_speed
 end
 
 function _init()
 end
 
-step_t = time()
-function _update60()
-  cls(0) -- clear here in case we want to print to screen outside of _draw
+_step_t = time()
+function _update()
+    -- clear here in case we want to print to screen outside of _draw
+    cls(0)
+
+    old_step = _step_t
+    _step_t = time()
+    step_dt = _step_t - old_step
 
-  old_step = step_t
-  step_t = time()
-  step_dt = step_t - old_step
+    foreach(update_hooks, function(f) f(step_dt) end)
 
-  handle_input()
-  qsort(World, function(a, b) return a.equipped != nil end)
-  foreach(World, function (e) e:update(step_dt) end)
+    handle_input()
+    World.foreach(function(e) if (not e.equipped) then e:update(step_dt) end end)
+    World.foreach(function(e) if (e.equipped) then e:update(step_dt) end end)
 
-  run_collisions()
+    run_collisions()
+
+    World.cull_the_dead()
 end
 
 function _draw()
-  foreach(qsort(World, function(a, b) return a.render_order < b.render_order end), function (e) e:render() end)
-end
+    qsort(World, function(a, b) return b.render_order < a.render_order end)
+    World.foreach(function(e) 
+        e:render()
+    end)
+end
\ No newline at end of file
diff --git a/dyl.p8 b/dyl.p8
index 0367033..423b331 100644
--- a/dyl.p8
+++ b/dyl.p8
@@ -61,21 +61,21 @@ __gfx__
 00504000005040000049000000490000006500000055500000500000005000000000000000000000000000000000000000000000000000000000000000000000
 00040000000400000400000004000000060000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
-00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
-00000000000000000000000004000000000000800000000000050000000600000000000000000000000000000000000000000000000000000000000000000000
-00000000000900000000000000490000000008e00006500000050000000500000000000000000000000000000000000000000000000000000000000000000000
-0049440000474400009000000097000000008e000055550000050000000500000000000000000000000000000000000000000000000000000000000000000000
-040000400407004004477770000570000058e0000055650000955000009550000000000000000000000000000000000000000000000000000000000000000000
-00555500005705000090000000005700006500000005050000055500000555000000000000000000000000000000000000000000000000000000000000000000
-00000000000550000000000000000570060000000000000000500000000500000000000000000000000000000000000000000000000000000000000000000000
+00000000000000000070000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
+00000000000000000070000000000000000000800000000000050000000600000000000000000000000000000000000000000000000000000000000000000000
+00000000000900000070000000000000000008e00006500000050000000500000000000000000000000000000000000000000000000000000000000000000000
+0049440000474400007000000000000000008e000055550000050000000500000000000000000000000000000000000000000000000000000000000000000000
+040000400407004009490000000900000058e0000055650000955000009550000000000000000000000000000000000000000000000000000000000000000000
+00555500005705000040000000447777006500000005050000055500000555000000000000000000000000000000000000000000000000000000000000000000
+00000000000550000000000000090000060000000000000000500000000500000000000000000000000000000000000000000000000000000000000000000000
 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
 00500000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
-00056000000600000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
-00000000005650600000000000000000000005006500000000000000000000000000000000000000000000000000000000000000000000000000000000000000
-00000000000560000000000000000005606056600650000000000000000000000000000000000000000000000000000000000000000000000000000000000000
-00000000000060000000000000000650005665000660000000000000000000000000000000000000000000000000000000000000000000000000000000000000
-00000000000650000005605000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
-00000000000000000056600000000000000006000050000000000000000000000000000000000000000000000000000000000000000000000000000000000000
+00056000000600000000000000000000006000000000050000000000000000000000000000000000000000000000000000000000000000000000000000000000
+00000000005650600000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
+00000000000560000000000005600000005665000000066000000000000000000000000000000000000000000000000000000000000000000000000000000000
+00000000000060000000000050000000066506060000056000000000000000000000000000000000000000000000000000000000000000000000000000000000
+00000000000650000005605000000000005000000000005600000000000000000000000000000000000000000000000000000000000000000000000000000000
+00000000000000000056600000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
 00000000000600000060000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
 00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
diff --git a/entity.lua b/entity.lua
index 945b787..56dcd74 100644
--- a/entity.lua
+++ b/entity.lua
@@ -2,11 +2,13 @@ Entities = {
     Player = 0,
     Sword = 1,
     Enemy = 2,
-    Bow = 3
+    Bow = 3,
+    Particle = 4
 }
 States = {
     Walk = "walk",
     Idle = "idle",
+    Active = "active",
     Equipped = "equipped",
     Slashing = "slashing",
     Drawing = "drawing",
@@ -51,6 +53,10 @@ function Entity:b_collidable()
     self.collision = true
     return self
 end
+function Entity:b_live_for(t)
+    self.life_time = t
+    return self
+end
 function Entity:b_line_of_sight(vec)
     self.line_of_sight = vec2(vec)
     return self
@@ -69,10 +75,13 @@ function Entity:transition_to(state_name)
         self.state = state_name
         self.state_stopwatch = 0
     end
-    print(self.state)
     return self
 end
 
+function Entity:kill()
+    self.life_time = -1
+end
+
 function Entity:update(dt)
     self:integrate(dt)
 
@@ -86,6 +95,10 @@ function Entity:update(dt)
 
     assert(self.transition_state)
     self:transition_state()
+
+    if self.life_time ~= nil then
+        self.life_time -= dt
+    end
 end
 
 function Entity:update_line_of_sight()
@@ -147,10 +160,11 @@ function Entity:integrate(dt)
 end
 
 _equipped_item_distance = 6
-function Entity:equipped_from(parent)
+function Entity:equipped_from(parent, dist)
+    dist = dist or _equipped_item_distance
     self.line_of_sight = vec2(parent.line_of_sight)
 
-    offset = (parent.line_of_sight * _equipped_item_distance)
+    offset = (parent.line_of_sight * dist)
 
     self.position = parent.position + offset
     self.sprite_position = parent.sprite_position + offset
@@ -203,5 +217,5 @@ function entity()
             collision = false
         }, Entity
     ))
-    return World[id]
+    return World.get(id)
 end
diff --git a/util.lua b/util.lua
index 157d7ad..b73838a 100644
--- a/util.lua
+++ b/util.lua
@@ -1,49 +1,51 @@
+update_hooks = {}
+
 -- https://pico-8.fandom.com/wiki/Qsort
-function qsort(a,c,l,r)
-	c,l,r=c or function(a,b) return a<b end,l or 1,r or #a
-	if l<r then
-		if c(a[r],a[l]) then
-			a[l],a[r]=a[r],a[l]
-		end
-		local lp,k,rp,p,q=l+1,l+1,r-1,a[l],a[r]
-		while k<=rp do
-			local swaplp=c(a[k],p)
-			-- "if a or b then else"
-			-- saves a token versus
-			-- "if not (a or b) then"
-			if swaplp or c(a[k],q) then
-			else
-				while c(q,a[rp]) and k<rp do
-					rp-=1
-				end
-				a[k],a[rp],swaplp=a[rp],a[k],c(a[rp],p)
-				rp-=1
-			end
-			if swaplp then
-				a[k],a[lp]=a[lp],a[k]
-				lp+=1
-			end
-			k+=1
-		end
-		lp-=1
-		rp+=1
-		-- sometimes lp==rp, so 
-		-- these two lines *must*
-		-- occur in sequence;
-		-- don't combine them to
-		-- save a token!
-		a[l],a[lp]=a[lp],a[l]
-		a[r],a[rp]=a[rp],a[r]
-		qsort(a,c,l,lp-1       )
-		qsort(a,c,  lp+1,rp-1  )
-		qsort(a,c,       rp+1,r)
-	end
+function qsort(a, c, l, r)
+    c, l, r = c or function(a, b) return a < b end, l or 1, r or #a
+    if l < r then
+        if c(a[r], a[l]) then
+            a[l], a[r] = a[r], a[l]
+        end
+        local lp, k, rp, p, q = l + 1, l + 1, r - 1, a[l], a[r]
+        while k <= rp do
+            local swaplp = c(a[k], p)
+            -- "if a or b then else"
+            -- saves a token versus
+            -- "if not (a or b) then"
+            if swaplp or c(a[k], q) then
+            else
+                while c(q, a[rp]) and k < rp do
+                    rp -= 1
+                end
+                a[k], a[rp], swaplp = a[rp], a[k], c(a[rp], p)
+                rp -= 1
+            end
+            if swaplp then
+                a[k], a[lp] = a[lp], a[k]
+                lp += 1
+            end
+            k += 1
+        end
+        lp -= 1
+        rp += 1
+        -- sometimes lp==rp, so
+        -- these two lines *must*
+        -- occur in sequence;
+        -- don't combine them to
+        -- save a token!
+        a[l], a[lp] = a[lp], a[l]
+        a[r], a[rp] = a[rp], a[r]
+        qsort(a, c, l, lp - 1)
+        qsort(a, c, lp + 1, rp - 1)
+        qsort(a, c, rp + 1, r)
+    end
     return a
 end
 
 function filter(a, pred)
     filtered = {}
-    for k,v in ipairs(a) do
+    for k, v in ipairs(a) do
         if pred(v) then
             filtered[k] = v
         end
@@ -53,9 +55,33 @@ end
 
 function fmt(x)
     t = type(x)
-    if t == "number" then return "" .. x
-    elseif t == "string" then return x
-    elseif t == "boolean" and x then return "true"
-    elseif t == "boolean" and not x then return "false" end
-    return "NA"
+    if t == "number" then
+        return "" .. x
+    elseif t == "string" then
+        return x
+    elseif t == "boolean" and x then
+        return "true"
+    elseif t == "boolean" and not x then
+        return "false"
+    end
+    return "_unknown_"
+end
+
+_button_states = {}
+function _update_button_states(_dt)
+    for button = 0, 20 do
+        if btn(button) then
+            if _button_states[button] == "up" then
+                _button_states[button] = "just_pressed"
+            else
+                _button_states[button] = "held"
+            end
+        else
+            _button_states[button] = "up"
+        end
+    end
 end
+update_hooks[1] = _update_button_states
+function button_just_pressed(id)
+    return _button_states[id] == "just_pressed"
+end
\ No newline at end of file
diff --git a/world.lua b/world.lua
index fd793a4..cb322df 100644
--- a/world.lua
+++ b/world.lua
@@ -1,5 +1,30 @@
+_World = {}
 World = {}
+
 function World.add(entity)
-    World[entity.id] = entity
+    _World[entity.id] = entity
     return World
+end
+
+function World.foreach(f)
+    for id, entity in pairs(_World) do
+        f(entity)
+    end
+end
+
+function World.cull_the_dead()
+    to_reap = {}
+    for id, e in pairs(_World) do
+        if (e.life_time ~= nil and e.life_time <= 0) then
+            to_reap[id] = e
+        end
+    end
+    for id, e in pairs(to_reap) do
+        _World[id] = nil
+    end
+    return _World
+end
+
+function World.get(id)
+    return _World[id]
 end
\ No newline at end of file
-- 
cgit v1.3