First-class slices, fixes #6

luigi/backend/ffisdl/spritebatch.lua

@@ -27,6 +27,10 @@ function SpriteBatch:constructor (image)
     self.sprites = {}
 end
 
+function SpriteBatch:clear ()
+    self.sprites = {}
+end
+
 --[[
 id = SpriteBatch:add( quad, x, y, r, sx, sy )
 

luigi/mosaic.lua

@@ -0,0 +1,117 @@
+local ROOT = (...):gsub('[^.]*$', '')
+
+local Backend = require(ROOT .. 'backend')
+local Base = require(ROOT .. 'base')
+
+local Mosaic = Base:extend()
+
+local imageCache = {}
+local sliceCache = {}
+
+local function loadImage (path)
+    if not imageCache[path] then
+        imageCache[path] = Backend.Image(path)
+    end
+
+    return imageCache[path]
+end
+
+function Mosaic.fromWidget (widget)
+    local mosaic = widget.mosaic
+    if mosaic and mosaic.slicePath == widget.slices then
+        return mosaic
+    end
+    if widget.slices then
+        widget.mosaic = Mosaic(widget.slices)
+        return widget.mosaic
+    end
+end
+
+function Mosaic:constructor (path)
+    local slices = self:loadSlices(path)
+    self.batch = Backend.SpriteBatch(slices.image)
+    self.slices = slices
+    self.slicePath = path
+end
+
+function Mosaic:setRectangle (x, y, w, h)
+    if self.x == x and self.y == y and self.width == w and self.height == h then
+        self.needsRefresh = false
+        return
+    end
+    self.needsRefresh = true
+    self.x, self.y, self.width, self.height = x, y, w, h
+end
+
+function Mosaic:loadSlices (path)
+    local slices = sliceCache[path]
+
+    if not slices then
+        slices = {}
+        sliceCache[path] = slices
+        local image = loadImage(path)
+        local iw, ih = image:getWidth(), image:getHeight()
+        local w, h = math.floor(iw / 3), math.floor(ih / 3)
+        local Quad = Backend.Quad
+
+        slices.image = image
+        slices.width = w
+        slices.height = h
+
+        slices.topLeft = Quad(0, 0, w, h, iw, ih)
+        slices.topCenter = Quad(w, 0, w, h, iw, ih)
+        slices.topRight = Quad(iw - w, 0, w, h, iw, ih)
+
+        slices.middleLeft = Quad(0, h, w, h, iw, ih)
+        slices.middleCenter = Quad(w, h, w, h, iw, ih)
+        slices.middleRight = Quad(iw - w, h, w, h, iw, ih)
+
+        slices.bottomLeft = Quad(0, ih - h, w, h, iw, ih)
+        slices.bottomCenter = Quad(w, ih - h, w, h, iw, ih)
+        slices.bottomRight = Quad(iw - w, ih - h, w, h, iw, ih)
+    end
+
+    return slices
+end
+
+function Mosaic:draw ()
+    local batch = self.batch
+
+    if not self.needsRefresh then
+        Backend.draw(batch)
+        return
+    end
+
+    self.needsRefresh = false
+
+    local x, y, w, h = self.x, self.y, self.width, self.height
+    local slices = self.slices
+    local sliceWidth, sliceHeight = slices.width, slices.height
+
+    local xScale = (w - sliceWidth * 2) / sliceWidth
+    local yScale = (h - sliceHeight * 2) / sliceHeight
+
+    batch:clear()
+
+    batch:add(slices.middleCenter, x + sliceWidth, y + sliceHeight, 0,
+    xScale, yScale)
+
+    batch:add(slices.topCenter, x + sliceWidth, y, 0,
+        xScale, 1)
+    batch:add(slices.bottomCenter, x + sliceWidth, y + h - sliceHeight, 0,
+        xScale, 1)
+
+    batch:add(slices.middleLeft, x, y + sliceHeight, 0,
+        1, yScale)
+    batch:add(slices.middleRight, x + w - sliceWidth, y + sliceHeight, 0,
+        1, yScale)
+
+    batch:add(slices.topLeft, x, y)
+    batch:add(slices.topRight, x + w - sliceWidth, y)
+    batch:add(slices.bottomLeft, x, y + h - sliceHeight)
+    batch:add(slices.bottomRight, x + w - sliceWidth, y + h - sliceHeight)
+
+    Backend.draw(batch)
+end
+
+return Mosaic

luigi/painter.lua

@@ -3,12 +3,13 @@ local ROOT = (...):gsub('[^.]*$', '')
 local Backend = require(ROOT .. 'backend')
 local Base = require(ROOT .. 'base')
 local Event = require(ROOT .. 'event')
+local Mosaic = require(ROOT .. 'mosaic')
 local Text = Backend.Text
 
 local Painter = Base:extend()
 
 local imageCache = {}
-local sliceCache = {}
+-- local sliceCache = {}
 
 local function intersectScissor (x, y, w, h)
     local sx, sy, sw, sh = Backend.getScissor()
@@ -39,72 +40,13 @@ function Painter:loadImage (path)
     return imageCache[path]
 end
 
--- TODO: make slices a seperate drawable
-
-function Painter:loadSlices (path)
-    local slices = sliceCache[path]
-
-    if not slices then
-        slices = {}
-        sliceCache[path] = slices
-        local image = self:loadImage(path)
-        local iw, ih = image:getWidth(), image:getHeight()
-        local w, h = math.floor(iw / 3), math.floor(ih / 3)
-        local Quad = Backend.Quad
-
-        slices.image = image
-        slices.width = w
-        slices.height = h
-
-        slices.topLeft = Quad(0, 0, w, h, iw, ih)
-        slices.topCenter = Quad(w, 0, w, h, iw, ih)
-        slices.topRight = Quad(iw - w, 0, w, h, iw, ih)
-
-        slices.middleLeft = Quad(0, h, w, h, iw, ih)
-        slices.middleCenter = Quad(w, h, w, h, iw, ih)
-        slices.middleRight = Quad(iw - w, h, w, h, iw, ih)
-
-        slices.bottomLeft = Quad(0, ih - h, w, h, iw, ih)
-        slices.bottomCenter = Quad(w, ih - h, w, h, iw, ih)
-        slices.bottomRight = Quad(iw - w, ih - h, w, h, iw, ih)
-    end
-
-    return slices
-end
-
 function Painter:paintSlices ()
     local widget = self.widget
-    local path = widget.slices
-    if not path then return end
-
+    local mosaic = Mosaic.fromWidget(widget)
+    if not mosaic then return end
     local x, y, w, h = widget:getRectangle(true)
-
-    local slices = self:loadSlices(path)
-
-    local batch = Backend.SpriteBatch(slices.image)
-
-    local xScale = (w - slices.width * 2) / slices.width
-    local yScale = (h - slices.height * 2) / slices.height
-
-    batch:add(slices.middleCenter, x + slices.width, y + slices.height, 0,
-    xScale, yScale)
-
-    batch:add(slices.topCenter, x + slices.width, y, 0,
-        xScale, 1)
-    batch:add(slices.bottomCenter, x + slices.width, y + h - slices.height, 0,
-        xScale, 1)
-
-    batch:add(slices.middleLeft, x, y + slices.height, 0,
-        1, yScale)
-    batch:add(slices.middleRight, x + w - slices.width, y + slices.height, 0,
-        1, yScale)
-
-    batch:add(slices.topLeft, x, y)
-    batch:add(slices.topRight, x + w - slices.width, y)
-    batch:add(slices.bottomLeft, x, y + h - slices.height)
-    batch:add(slices.bottomRight, x + w - slices.width, y + h - slices.height)
-
-    Backend.draw(batch)
+    mosaic:setRectangle(x, y, w, h)
+    mosaic:draw()
 end
 
 function Painter:paintBackground ()