1 files changed, 171 insertions, 0 deletions
diff --git a/libs/moonshine/init.lua b/libs/moonshine/init.lua
new file mode 100644
index 0000000..431c6c0
--- /dev/null
+++ b/libs/moonshine/init.lua
@@ -0,0 +1,171 @@
+--[[
+The MIT License (MIT)
+
+Copyright (c) 2017 Matthias Richter
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+]]--
+
+local BASE = ...
+
+local moonshine = {}
+
+moonshine.draw_shader = function(buffer, shader)
+  local front, back = buffer()
+  love.graphics.setCanvas(front)
+  love.graphics.clear()
+  if shader ~= love.graphics.getShader() then
+    love.graphics.setShader(shader)
+  end
+  love.graphics.draw(back)
+end
+
+moonshine.chain = function(w,h,effect)
+  -- called as moonshine.chain(effect)'
+  if h == nil then
+    effect, w,h = w, love.window.getMode()
+  end
+  assert(effect ~= nil, "No effect")
+
+  local front, back = love.graphics.newCanvas(w,h), love.graphics.newCanvas(w,h)
+  local buffer = function()
+    back, front = front, back
+    return front, back
+  end
+
+  local disabled = {} -- set of disabled effects
+  local chain = {}
+  chain.resize = function(w, h)
+    front, back = love.graphics.newCanvas(w,h), love.graphics.newCanvas(w,h)
+    return chain
+  end
+
+  chain.draw = function(func, ...)
+    -- save state
+    local canvas = love.graphics.getCanvas()
+    local shader = love.graphics.getShader()
+    local fg_r, fg_g, fg_b, fg_a = love.graphics.getColor()
+
+    -- draw scene to front buffer
+    love.graphics.setCanvas((buffer())) -- parens are needed: take only front buffer
+    love.graphics.clear(love.graphics.getBackgroundColor())
+    func(...)
+
+    -- save more state
+    local blendmode = love.graphics.getBlendMode()
+
+    -- process all shaders
+    love.graphics.setColor(fg_r, fg_g, fg_b, fg_a)
+    love.graphics.setBlendMode("alpha", "premultiplied")
+    for _,e in ipairs(chain) do
+      if not disabled[e.name] then
+        (e.draw or moonshine.draw_shader)(buffer, e.shader)
+      end
+    end
+
+    -- present result
+    love.graphics.setShader()
+    love.graphics.setCanvas(canvas)
+    love.graphics.draw(front,0,0)
+
+    -- restore state
+    love.graphics.setBlendMode(blendmode)
+    love.graphics.setShader(shader)
+  end
+
+  chain.next = function(e)
+    if type(e) == "function" then
+      e = e()
+    end
+    assert(e.name, "Invalid effect: must provide `name'.")
+    assert(e.shader or e.draw, "Invalid effect: must provide `shader' or `draw'.")
+    table.insert(chain, e)
+    return chain
+  end
+  chain.chain = chain.next
+
+  chain.disable = function(name, ...)
+    if name then
+      disabled[name] = name
+      return chain.disable(...)
+    end
+  end
+
+  chain.enable = function(name, ...)
+    if name then
+      disabled[name] = nil
+      return chain.enable(...)
+    end
+  end
+
+  setmetatable(chain, {
+    __call = function(_, ...) return chain.draw(...) end,
+    __index = function(_,k)
+      for _, e in ipairs(chain) do
+        if e.name == k then return e end
+      end
+      error(("Effect `%s' not in chain"):format(k), 2)
+    end,
+    __newindex = function(_, k, v)
+      if k == "parameters" or k == "params" or k == "settings" then
+        for e,par in pairs(v) do
+          for k,v in pairs(par) do
+            chain[e][k] = v
+          end
+        end
+      else
+        rawset(chain, k, v)
+      end
+    end
+  })
+
+  return chain.next(effect)
+end
+
+moonshine.Effect = function(e)
+  -- set defaults
+  for k,v in pairs(e.defaults or {}) do
+    assert(e.setters[k], ("No setter for parameter `%s'"):format(k))(v, k)
+    e.setters[k](v,k)
+  end
+
+  -- expose setters
+  return setmetatable(e, {
+    __newindex = function(self,k,v)
+      assert(self.setters[k], ("Unknown property: `%s.%s'"):format(e.name, k))
+      self.setters[k](v, k)
+    end})
+end
+
+-- autoloading effects
+moonshine.effects = setmetatable({}, {__index = function(self, key)
+  local ok, effect = pcall(require, BASE .. "." .. key)
+  if not ok then
+    error("No such effect: "..key, 2)
+  end
+
+  -- expose moonshine to effect
+  local con = function(...) return effect(moonshine, ...) end
+
+  -- cache effect constructor
+  self[key] = con
+  return con
+end})
+
+return setmetatable(moonshine, {__call = function(_, ...) return moonshine.chain(...) end})