feat(world): add zSorting

Fixes #73

framework/scenes/world/actors/init.lua

@@ -39,6 +39,7 @@ function Actor:new(world, position)
   self:_initVisual(self.def.visuals or {})
 
   self.isDestroyed = false
+  self.depth = self.def.depth or 0
 
   self.timers = TweenManager(self)
 

framework/scenes/world/init.lua

@@ -37,6 +37,8 @@ local Vector3D = require "framework.libs.brinevector3D"
 
 local GFX = require "framework.scenes.world.actors.gfx"
 
+local comparisons = require "framework.scenes.world.zsort"
+
 local function _tryFunction(toUpdate, dt, func)
     if (toUpdate ~= nil) then
         func(dt)
@@ -63,11 +65,21 @@ function World:new(datas)
     self.type = self.def.type or "2D"
     self.drawShadow = (self.def.drawShadow == true)
 
+    self.currentCreationID = 0
+
     World.super.new(self)
 
+    self:_setSorting()
     self:_load()
 end
 
+function World:_setSorting()
+    self.sort = comparisons.depthSort
+    if self.type == "3D" then
+        self.sort = comparisons.zSort
+    end
+end
+
 function World:onLoad()
 
 end
@@ -229,16 +241,23 @@ function World:newActor(name, x, y, z, properties, mapname)
 end
 
 function World:showGFX(effect, position, useMiddle)
-    table.insert(self.actors, GFX(self, position, effect, false, (useMiddle == true)))
+    local gfx = GFX(self, position, effect, false, (useMiddle == true))
+    gfx.creationID = self.currentCreationID
+    self.currentCreationID = self.currentCreationID + 1
+    table.insert(self.actors, gfx)
 end
 
 function World:addActor(name, position)
     local Actor = self:_getActorObject(name)
     if (name == "player") then
         self.player = Actor(self, position)
+        self.player.creationID = self.currentCreationID
     else
-        table.insert(self.actors, Actor(self, position))
+        local actor = Actor(self, position)
+        table.insert(self.actors, actor)
+        actor.creationID = self.currentCreationID
     end
+    self.currentCreationID = self.currentCreationID + 1
 end
 
 function World:removeActor(actor)
@@ -309,7 +328,10 @@ function World:getBodiesInCube(x, y, z, w, h, d)
 -- Handle shapes, which make know what object is visible or not
 
 function World:addTerrain(body)
-    self:registerShape(Terrain(self, body.position, body.dimensions))
+    local terrain = Terrain(self, body.position, body.dimensions)
+    terrain.creationID = self.currentCreationID
+    self.currentCreationID = self.currentCreationID + 1
+    self:registerShape(terrain)
 end
 
 function World:registerShape(actor)
@@ -337,6 +359,7 @@ end
 function World:drawShapes()
     local position, dimensions = self.camera:getViewCoordinate()
     local shapes = self:getShapeInRect(position, dimensions)
+    table.sort(shapes, self.sort)
     for _, shape in ipairs(shapes) do
         shape:draw()
     end

framework/scenes/world/terrain.lua

@@ -27,6 +27,7 @@ local Vector3D = require "framework.libs.brinevector3D"
 function MappedBox:new(world, position, dimensions)
   self.world = world
   self.position = Vector3D(position.x, position.y, position.z or 0)
+  self.depth = -1
 
   MappedBox.super.new(self, dimensions)
   self.haveLine = false

framework/scenes/world/zsort.lua

@@ -0,0 +1,54 @@
+local comparisons = {}
+
+
+function comparisons.depthSort(itemA, itemB)
+    local aDepth, aID = itemA.depth, itemA.creationID
+    local bDepth, bID = itemB.depth, itemB.creationID
+    local comparison = 0
+    if aDepth > bDepth then
+        comparison = 1
+    elseif aDepth < bDepth then
+        comparison = -1
+    else
+        if aID > bID then
+            comparison = 1
+        elseif aID < bID then
+            comparison = -1
+        end
+    end
+    return comparison == -1
+end
+
+function comparisons.zSort(itemA, itemB)
+    local aY, aZ, aH, aD = itemA.position.y, itemA.position.z, itemA.dimensions.h, itemA.dimensions.d
+    local bY, bZ,bH, bD = itemB.position.y, itemB.position.z, itemB.dimensions.h, itemB.dimensions.d
+
+    local comparison = 0
+
+    if aY + aH <= bY then
+        -- item A is completely behind item B
+        comparison = -1
+    elseif bY + bH <= aY then
+        -- item B is completely behind item A
+        comparison = 1
+    elseif aZ >= bZ + bD then
+        -- item A is completely above item B
+        comparison = 1
+    elseif bZ >= aZ + aD then
+        -- item B is completely above item A
+        comparison = -1
+    elseif aY + aH > bY + bH then --(aY - aZ) + aH > (bY - bZ) + bH then
+        -- item A's forward-most point is in front of item B's forward-most point
+        comparison = 1
+    elseif aY + aH < bY + bH then --aY < (bY - bZ) + bH then
+        -- item B's forward-most point is in front of item A's forward-most point
+        comparison = -1
+    else
+        -- item A's forward-most point is the same than item B's forward-most point
+        return comparisons.depthSort(itemA, itemB)
+    end
+
+    return comparison == -1 
+end
+
+return comparisons