feat: enemies chase entities, get stunned and fly off the screen

This commit introduces the following features:

- enemies have a simple target system, chasing a `Pos`. This can be a
  moving target (e.g., giving them the player's `Pos` reference) or
  still.
- there is a simple status system: entities hit may be "stunned" and,
  when dead, are "phantom" (i.e., they do not collide with other
  entities).
- when killed, entities fly off the screen.

1 files changed, 203 insertions, 95 deletions

diff --git a/raccoon.lua b/raccoon.lua
index df57514..18939a1 100644
--- a/raccoon.lua
+++ b/raccoon.lua
@@ -242,16 +242,18 @@ function Pos:init(x,y)
     self.y = y or 0
     return self
 end
-function Pos:on_ground()
-    -- Check center tile
-    local center = mget((self.x + 8/2)//8, (self.y + 8)//8)
-    if fget(center, 0) then return center end
-    -- Check left tile
-    local left = mget((self.x + 1)//8, (self.y + 8)//8)
-    if fget(left, 0) then return left end
-    -- Check right tile
-    local right = mget((self.x + 8 - 1)//8, (self.y + 8)//8)
-    if fget(right, 0) then return right end
+function Pos:on_ground(phantom)
+    if not phantom then
+        -- Check center tile
+        local center = mget((self.x + 8/2)//8, (self.y + 8)//8)
+        if fget(center, 0) then return center end
+        -- Check left tile
+        local left = mget((self.x + 1)//8, (self.y + 8)//8)
+        if fget(left, 0) then return left end
+        -- Check right tile
+        local right = mget((self.x + 8 - 1)//8, (self.y + 8)//8)
+        if fget(right, 0) then return right end
+    end
     -- In mid air
     return nil
 end
@@ -259,6 +261,17 @@ function Pos:to_screen(lpos)
     return self.x - lpos.x, self.y - lpos.y
 end
 
+Health = Component("Health")
+function Health:init(max)
+    self.cur = max
+    self.max = max
+    return self
+end
+function Health:damage(d)
+    self.cur = math.max(0,self.cur-d)
+    return self.cur
+end
+
 Movement = Component("Movement")
 function Movement:init(accel, max)
     -- direction facing
@@ -274,6 +287,12 @@ function Movement:is_moving()
     return self.cur.x ~= 0 or self.cur.y ~= 0
 end
 
+MovementAI = Component("MovementAI")
+function MovementAI:init()
+    -- TODO
+    return self
+end
+
 Pixel = Component("Pixel")
 function Pixel:init(c)
     self.color = c
@@ -317,12 +336,26 @@ function Entities:init(list)
     return self
 end
 
-local Action = Component()
-function Action:init(a,b)
-    self.a = a
-    self.b = b
+Status = Component("Status")
+Status.keys = { "phantom", "stunned" }
+function Status:init()
+    for _,s in ipairs(Status.keys) do self[s] = nil end
     return self
 end
+function Status:tick()
+    for _,s in ipairs(Status.keys) do
+        if self[s] then
+            self[s] = self[s] - 1
+            if self[s] < 0 then
+                self[s] = nil
+            end
+        end
+    end
+end
+for _,s in ipairs(Status.keys) do
+    Status["set_"..s] = function(self,d) self[s] = 60 * (d or 1); return self end
+    Status["is_"..s] = function(self) return self[s] end
+end
 
 CircleEffect = Component("CircleEffect")
 function CircleEffect:init(r2, r1, time, color)
@@ -362,13 +395,17 @@ function Particles:spawn(pos, entities)
     end
 end
 
-function ForceField:init(force,range,instant)
 ForceField = Component("ForceField")
+function ForceField:init(force,range,is_target,instant)
     self.force = force or 1
     self.range = range or 1
+    self.is_target = is_target or function(_) return true end
     self.instant = instant
     return self
 end
+function ForceField.by_id(id)
+    return function(e) return e.id ~= id end
+end
 
 Metadata = Component("Metadata")
 function Metadata:init(name)
@@ -376,6 +413,30 @@ function Metadata:init(name)
     return self
 end
 
+Action = Component("Action")
+function Action:init(a,b)
+    self.a = a
+    self.b = b
+    return self
+end
+function Action.forcefield(entity,game)
+    local pos = entity:get_pos()
+    table.insert(
+        game.entities,
+        Entity():with({
+            Pos(pos.x,pos.y),
+            ForceField(2,10,ForceField.by_id(entity.id),true),
+            CircleEffect(20)}))
+end
+
+Target = Component("Target")
+function Target:init(pos, prox, sticky)
+    self.pos = pos
+    self.prox = prox or 5
+    self.sticky = sticky
+    return self
+end
+
 local ForceFieldSystem = System(Pos,ForceField)
 function ForceFieldSystem:exec(entity,enemies)
     local pos = entity:get_pos()
@@ -385,14 +446,31 @@ function ForceFieldSystem:exec(entity,enemies)
             local pos1 = e:get_pos()
             local dist,vec = util.distance(pos,pos1)
             if dist < ff.range then
-                if e.has_component[Metadata] then
-                    local meta = e.get_component[Metadata]
-                    trace("Hit " .. meta.name .. " at position " .. pos1.x .. " " .. pos1.y)
-                else
-                    trace("Hit entity at position " .. pos1.x .. " " .. pos1.y)
+                local death_blow = 1
+                if e:has_status() then
+                    e:get_status():set_stunned(1)
+                end
+                if e:has_health() then
+                    local h = e:get_health():damage(2)
+                    if h == 0 then
+                        if e:has_status() then
+                            e:get_status():set_stunned(3)
+                            e:get_status():set_phantom(3)
+                        end
+                        death_blow = 2 + math.random(2)
+                    end
+                end
+                if e:has_movement() then
+                    local mov = e:get_movement()
+                    mov.cur.x = mov.cur.x + util.signum(vec[1]) * death_blow * ff.force
+                    mov.cur.y = mov.cur.y - death_blow * ff.force
                 end
-                mov.cur.x = mov.cur.x + util.signum(vec[1]) * ff.force
-                mov.cur.y = mov.cur.y - ff.force
+                -- if e:has_metadata() then
+                --     local meta = e:get_metadata()
+                --     trace("Hit " .. meta.name .. " at position " .. pos1.x .. " " .. pos1.y)
+                -- else
+                --     trace("Hit entity at position " .. pos1.x .. " " .. pos1.y)
+                -- end
             end
         end
     end
@@ -418,72 +496,68 @@ end
 
 local MovementSystem = System(Pos, Movement)
 function MovementSystem:exec(entity)
-    local pos = entity.get_component[Pos]
-    local move = entity.get_component[Movement]
-    if entity.has_component[Input] then
-        local input = entity.get_component[Input]
-        local left, right = input.raw[3], input.raw[4]
-        -- local debug
-        -- if left then debug = " left, " else debug = " ____, " end
-        -- if right then debug = debug .. "right" else debug = debug .. "_____" end
-        if left and not right then
-            if move.dir then
-                move.cur.x = 0
-            end
-            move.dir = false
-            move.cur.x = math.max(-move.max.x, move.cur.x - move.accel.x)
-        elseif right and not left then
-            if not move.dir then
-                move.cur.x = 0
+    local rm, components = false, {}
+
+    local pos = entity:get_pos()
+    local move = entity:get_movement()
+    local status = Status()
+    if entity:has_status() then
+        status = entity:get_status()
+    end
+    -- Horizontal movement
+    local left, right = false, false
+    if not status:is_stunned() then
+        if entity:has_input() then
+            local input = entity:get_input()
+            left, right = input.raw[3], input.raw[4]
+        elseif entity:has_movementai() then
+            if entity:has_target() then
+                local target = entity:get_target()
+                local delta = target.pos.x - pos.x
+                if -target.prox < delta and delta < target.prox and not target.sticky then
+                    table.insert(components, target)
+                else
+                    left, right = delta < 0, delta > 0
+                end
             end
-            move.dir = true
-            move.cur.x = math.min(move.max.x, move.cur.x + move.accel.x)
-        else
-            -- TODO
         end
-        -- horizontal movement
-        --move:update_speedx(input.raw[3], input.raw[4])
-    --     if input.raw[3] then
-    --         if speed.right then
-    --             speed.cur.x = 0
-    --         end
-    --         speed.right = false
-    --         speed.cur.x = math.max(-speed.max, speed.cur.x - speed.accel)
-    --     elseif input.raw[4] then
-    --         if not speed.right then
-    --             speed.cur.x = 0
-    --         end
-    --         speed.right = true
-    --         speed.cur.x = math.min(speed.max, speed.cur.x + speed.accel)
-    --     end
-        if entity.has_component[Jump] then
-            local jump = entity.get_component[Jump]
-            if jump.jumping then
-                move.cur.y = move.cur.y + .2
-                if pos:on_ground() then
-                    jump.jumping = false
-                end
---                 if jump.cur < jump.pwr then
---                     jump.cur = jump.cur + 1
---                     speed.cur.y = - (5 / jump.cur)
---                 else
---                     jump.jumping = false
---                 end
-            elseif input.rawp[1] and pos:on_ground() then
-                move.cur.y = -4
-                jump.jumping = true
---                 if jump.cur > 0 then
---                     jump.cur = jump.cur - 1
---                 elseif speed.on_ground then
---                 end
+    end
+    if left and not right then
+        if move.dir then
+            move.cur.x = 0
+        end
+        move.dir = false
+        move.cur.x = math.max(-move.max.x, move.cur.x - move.accel.x)
+    elseif right and not left then
+        if not move.dir then
+            move.cur.x = 0
+        end
+        move.dir = true
+        move.cur.x = math.min(move.max.x, move.cur.x + move.accel.x)
+    end
+    -- Vertical movement
+    if entity:has_jump() and not status:is_stunned() then
+        local jump = entity:get_jump()
+        local up = false
+        if entity:has_input() then
+            local input = entity:get_input()
+            up = input.rawp[1]
+        end
+        if jump.jumping then
+            move.cur.y = move.cur.y + .2
+            if pos:on_ground() then
+                jump.jumping = false
             end
+        elseif up and pos:on_ground() then
+            move.cur.y = -4
+            jump.jumping = true
         end
-    else
-        -- AI
     end
+    -- Gravity
+    move.cur.y = math.min(2, move.cur.y + .2)
     -- Horizontal friction
     local friction = .1
-    if pos:on_ground() then
+    if pos:on_ground(status:is_phantom()) then
         friction = .2
     end
     if move.cur.x > 0 then
@@ -491,25 +565,25 @@ function MovementSystem:exec(entity)
     else
         move.cur.x = math.min(0, move.cur.x + friction)
     end
-    -- Gravity
-    move.cur.y = math.min(2, move.cur.y + .2)
     -- -- collision check
     local posx = pos.x + move.cur.x
     local posy = pos.y + move.cur.y
-    -- -- movement on the X
     local collx = false
-    for y = pos.y//8,(pos.y+7)//8 do
-        collx = collx or fget(mget(posx//8,y),0) or fget(mget((posx+7)//8,y),0)
-    end
-    -- movement on the Y
     local colly = false
-    for x = pos.x//8,(pos.x+7)//8 do
-        colly = colly or fget(mget(x,posy//8),0) or fget(mget(x,(posy+7)//8),0)
+    if not status:is_phantom() then
+        -- -- movement on the X
+        for y = pos.y//8,(pos.y+7)//8 do
+            collx = collx or fget(mget(posx//8,y),0) or fget(mget((posx+7)//8,y),0)
+        end
+        -- movement on the Y
+        for x = pos.x//8,(pos.x+7)//8 do
+            colly = colly or fget(mget(x,posy//8),0) or fget(mget(x,(posy+7)//8),0)
+        end
+        -- local cx, cy
+        -- if collx then cx = "true" else cx = "false" end
+        -- if colly then cy = "true" else cy = "false" end
+        -- print("Collision: "..cx..", "..cy)
     end
-    -- local cx, cy
-    -- if collx then cx = "true" else cx = "false" end
-    -- if colly then cy = "true" else cy = "false" end
-    -- print("Collision: "..cx..", "..cy)
     if not collx then
          pos.x = posx
     end
@@ -519,6 +593,23 @@ function MovementSystem:exec(entity)
     else
         move.cur.y = 0
     end
+
+    if rm then components = {} end
+    return rm or next(components), components  -- next(table) used as a "not empty" check
+end
+
+local StatusSystem = System(Status)
+function StatusSystem:exec(entity)
+    entity:get_status():tick()
+end
+
+local BoundarySystem = System(Pos,Health)
+function BoundarySystem:exec(entity,lpos)
+    local health = entity:get_health()
+    if health.cur <= 0 then
+        local x, y = entity:get_pos():to_screen(lpos)
+        return x < 0 or y < 0 or x > util.screen.width or y > util.screen.height
+    end
 end
 
 local DrawingSystem = System(Pos)
@@ -617,6 +708,16 @@ function ParticlesSystem:exec(entity, game)
     end
 end
 
+local TargetSystem = System(Movement,MovementAI)
+function TargetSystem:exec(entity)
+    -- TODO to be removed
+    if not entity:has_target() then
+        local x, y = math.random(util.screen.width), math.random(util.screen.height)
+        trace("New target: "..x..", "..y)
+        entity:with(Target(Pos(x,y)))
+    end
+end
+
 local player = Entity():with({
     Metadata("Giulia"), Sprite(256),
     Pos(100,10), Health(100), Status(),
@@ -663,13 +764,20 @@ function TIC()
     cls(0)
 
     InputSystem:run(game.entities)
+    TargetSystem:run(game.entities)
+
+    StatusSystem:run(game.entities)
+
     MovementSystem:run(game.entities)
     ActionSystem:run(game.entities, game)
-    EffectSystem:run(game.entities)
     ForceFieldSystem:run(game.entities, game.entities)
+
     PosAnimSystem:run(game.entities)
+    EffectSystem:run(game.entities)
     ParticlesSystem:run(game.entities, game)
+
     LevelSystem:run(game.levels, game)
+    BoundarySystem:run(game.entities, game.levels[game.level]:get_pos())
 
     DrawingSystem:draw(game)