fix: particles option set to offmain

Simple fix to the following bug reported by ~demodulatingswan:

> With the particles option set to off, all particles are created and
> added to the entities table, and then erased from the entities table
> by their own update method. When that happens, the draw method is
> never called. But sometimes, the draw method of a particle is called
> before the update method. Because the animation attribute is nil when
> the particles option is set to off, the attempt to call a function
> from this attribute fails and crashes the game. This fix changes the
> draw method to do nothing when the particles option is set to off.
> [...]

Instead of skipping a draw like in their patch, I chosed to destroy the
particle on creation if `particles` is disabled.

2 files changed, 2 insertions, 0 deletions

diff --git a/src/particle.lua b/src/particle.lua
index d3543d4..087f02c 100644
--- a/src/particle.lua
+++ b/src/particle.lua
@@ -12,6 +12,7 @@ local g = anim8.newGrid(16, 16, Particle.image:getWidth(),
 
 function Particle:new(x, y, dx, dy)
   if not particles then
+    self:destroy()
     return nil
   end
   self.x = x or 0
diff --git a/src/walk_particle.lua b/src/walk_particle.lua
index edb81d4..b7e927f 100644
--- a/src/walk_particle.lua
+++ b/src/walk_particle.lua
@@ -12,6 +12,7 @@ local g = anim8.newGrid(8, 8, Particle.image:getWidth(),
 
 function Particle:new(x, y, dx)
   if not particles then
+    self:destroy()
     return nil
   end
   self.x = x or 0