From 993e029a2f672d578f74a4b54e497f98dacc964a Mon Sep 17 00:00:00 2001
From: Tim Anema <timanema@gmail.com>
Date: Fri, 28 Nov 2014 16:56:05 -0500
Subject: [PATCH] made circle shadow bodies use arc instead of circle, also
 optimized so they were not drawn if not neccessary

---
 lib/body.lua     | 15 ++++++++++++++-
 lib/init.lua     |  2 +-
 lib/light.lua    |  3 +++
 lib/stencils.lua |  2 +-
 4 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/lib/body.lua b/lib/body.lua
index 7da797b..c92f31f 100644
--- a/lib/body.lua
+++ b/lib/body.lua
@@ -636,7 +636,20 @@ function body:calculateCircleShadow(light)
 
   local radius = math.sqrt(math.pow(curShadowGeometry[7] - curShadowGeometry[5], 2) + math.pow(curShadowGeometry[8]-curShadowGeometry[6], 2)) / 2
   local cx, cy = (curShadowGeometry[5] + curShadowGeometry[7])/2, (curShadowGeometry[6] + curShadowGeometry[8])/2
-  curShadowGeometry.circle = {cx, cy, radius}
+  local angle1 = math.atan2(curShadowGeometry[6] - cy, curShadowGeometry[5] - cx)
+  local angle2 = math.atan2(curShadowGeometry[8] - cy, curShadowGeometry[7] - cx)
+  local distance1 = math.sqrt(math.pow(light.x - self.x, 2) + math.pow(light.y - self.y, 2)) / 2 
+  local distance2 = math.sqrt(math.pow(light.x - cx, 2) + math.pow(light.y - cy, 2)) / 2 
+
+  if distance1 <= self.radius then
+    curShadowGeometry.circle = {cx, cy, radius, 0, (math.pi * 2)}
+  elseif distance2 < light.range then -- dont draw circle if way off screen
+    if angle1 > angle2 then
+      curShadowGeometry.circle = {cx, cy, radius, angle1, angle2}
+    else
+      curShadowGeometry.circle = {cx, cy, radius, angle1 - math.pi, angle2 - math.pi}
+    end
+  end
 
   curShadowGeometry.red = self.red
   curShadowGeometry.green = self.green
diff --git a/lib/init.lua b/lib/init.lua
index 77854c5..e53fa3f 100644
--- a/lib/init.lua
+++ b/lib/init.lua
@@ -1,7 +1,7 @@
 --[[
 The MIT License (MIT)
 
-Copyright (c) 2014 Marcus Ihde
+Copyright (c) 2014 Marcus Ihde, Tim Anema
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/lib/light.lua b/lib/light.lua
index a2a7f42..c8d8f29 100644
--- a/lib/light.lua
+++ b/lib/light.lua
@@ -165,6 +165,9 @@ function light:drawShadow(l,t,w,h,s,bodies, canvas)
             shadow_geometry[k].blue * (1.0 - shadow_geometry[k].alpha)
           )
           love.graphics.polygon("fill", unpack(shadow_geometry[k]))
+          if shadow_geometry[k].circle then
+            love.graphics.arc("fill", unpack(shadow_geometry[k].circle))
+          end
         end
       end
 
diff --git a/lib/stencils.lua b/lib/stencils.lua
index 2a1a903..e3ff160 100644
--- a/lib/stencils.lua
+++ b/lib/stencils.lua
@@ -7,7 +7,7 @@ function stencils.shadow(geometry, bodies)
       if geometry[i].alpha == 1.0 then
         love.graphics.polygon("fill", unpack(geometry[i]))
         if geometry[i].circle then
-          love.graphics.circle("fill", unpack(geometry[i].circle))
+          love.graphics.arc("fill", unpack(geometry[i].circle))
         end
       end
     end