From f04d0c6b4ea9779f3c85dd4b02e6f9be31c0aafc Mon Sep 17 00:00:00 2001
From: Kazhnuz <antoine@sortilege.net>
Date: Thu, 2 May 2019 19:51:43 +0200
Subject: [PATCH] modules/world: initial gravity system

---
 examples/gameplay/plateform/actors/player.lua |  1 +
 gamecore/modules/world/actors/actor2D.lua     | 28 +++++++++++++++++++
 gamecore/modules/world/baseworld.lua          | 11 ++++++++
 3 files changed, 40 insertions(+)

diff --git a/examples/gameplay/plateform/actors/player.lua b/examples/gameplay/plateform/actors/player.lua
index 5a38e40..862bba9 100644
--- a/examples/gameplay/plateform/actors/player.lua
+++ b/examples/gameplay/plateform/actors/player.lua
@@ -4,6 +4,7 @@ local Player = Base:extend()
 function Player:new(world, x, y, id)
   Player.super.new(self, world, "player", x, y, 16, 24, true)
   self:setSprite("player", 8, 12)
+  self:setYGravity(480)
 end
 
 function Player:update(dt)
diff --git a/gamecore/modules/world/actors/actor2D.lua b/gamecore/modules/world/actors/actor2D.lua
index 1c64f0a..c4d8836 100644
--- a/gamecore/modules/world/actors/actor2D.lua
+++ b/gamecore/modules/world/actors/actor2D.lua
@@ -66,6 +66,7 @@ function Actor2D:initPhysics(x, y, w, h, isSolid)
   self.yfrc   = 0
 
   self.bounceFactor   = 0
+  self:initGravity()
 
   self.isSolid = isSolid or false
 
@@ -115,6 +116,8 @@ function Actor2D:setFilter()
 end
 
 function Actor2D:autoMove(dt)
+  self:applyGravity(dt)
+
   local newx, newy, cols, colNumber = self:move(self.x + self.xsp * dt, self.y + self.ysp * dt)
 
   -- apply after the movement the friction, until the player stop
@@ -160,6 +163,31 @@ function Actor2D:move(dx, dy)
   return self.x, self.y, cols, colNumber
 end
 
+function Actor2D:initGravity()
+  local xgrav, ygrav
+
+  if (self.world.gravity.isDefault) then
+    self.xgrav = self.world.gravity.xgrav
+    self.ygrav = self.world.gravity.ygrav
+  else
+    self.xgrav = 0
+    self.ygrav = 0
+  end
+end
+
+function Actor2D:setXGravity(grav)
+  self.xgrav = grav
+end
+
+function Actor2D:setYGravity(grav)
+  self.ygrav = grav
+end
+
+function Actor2D:applyGravity(dt)
+  self.xsp = self.xsp + self.xgrav * dt
+  self.ysp = self.ysp + self.ygrav * dt
+end
+
 -- DRAW FUNCTIONS
 -- Draw the actors.
 
diff --git a/gamecore/modules/world/baseworld.lua b/gamecore/modules/world/baseworld.lua
index 41ba0fa..844fb17 100644
--- a/gamecore/modules/world/baseworld.lua
+++ b/gamecore/modules/world/baseworld.lua
@@ -41,6 +41,7 @@ function BaseWorld:new(scene, actorlist, mapfile)
   self:initPlayers()
   self:setActorList(actorlist)
   self:initMap(mapfile)
+  self:setGravity()
 end
 
 function BaseWorld:setActorList(actorlist)
@@ -58,6 +59,16 @@ function BaseWorld:initMap(mapfile)
   self.mapfile              = mapfile
 end
 
+function BaseWorld:setGravity(xgrav, ygrav, isDefault)
+  local xgrav     = xgrav or 0
+  local ygrav     = ygrav or 0
+  local isDefault = isDefault or 0
+
+  self.gravity = {}
+  self.gravity.xgrav, self.gravity.ygrav = xgrav, ygrav
+  self.gravity.isDefault = isDefault
+end
+
 -- ACTOR MANAGEMENT FUNCTIONS
 -- Basic function to handle actors