Added error checking and offsets for flipping sprites

src/spritesheet.lua

@@ -1,25 +1,33 @@
 local module = {}
 
 function module.create(file, rows, columns)
-    local spritesheet = {
-        image=love.graphics.newImage(image),
-        quads={}
-    }
+    if columns == nil then columns = 1 end
 
-    if image == nil then 
+    if love.filesystem.getInfo(file) == nil then 
         love.errorhandler("file: "..file.." was not found.")
     end
     
+    image = love.graphics.newImage(file)
+
+    local spritesheet = {
+        image=image,
+        quads={}
+    }
+
     local width, height = image:getWidth()/rows, image:getHeight()/columns
+    spritesheet.width = width
+    spritesheet.height = height
 
     for r = 0, rows-1 do
-        for c = 0, rows-1 do 
-            table.insert(spritesheet.quads, love.graphics.newQuad(width*(r-1),height*(c-1),width,height,image:getDimensions()))
+        for c = 0, columns-1 do 
+            table.insert(spritesheet.quads, love.graphics.newQuad(width*r,height*c,width,height,image:getDimensions()))
         end
     end
 
-    function spritesheet:draw(frame, x, y)
-        love.graphics.draw(self.quads[frame], x, y)
+    function spritesheet:draw(frame, x, y, sx, sy, ox, oy)
+        if sx == -1 then ox = self.width end
+        if sy == -1 then oy = self.height end
+        love.graphics.draw(self.image, self.quads[frame], x, y, 0, sx, sy, ox, oy)
     end
 
     return spritesheet