Initial Commit

* Basic Game Implementation

libs/moonshine/desaturate.lua

@@ -0,0 +1,52 @@
+--[[
+Public domain:
+
+Copyright (C) 2017 by Matthias Richter <vrld@vrld.org>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
+FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.
+]]--
+
+return function(moonshine)
+  local shader = love.graphics.newShader[[
+    extern vec4 tint;
+    extern number strength;
+    vec4 effect(vec4 color, Image texture, vec2 tc, vec2 _) {
+      color = Texel(texture, tc);
+      number luma = dot(vec3(0.299, 0.587, 0.114), color.rgb);
+      return mix(color, tint * luma, strength);
+    }]]
+
+  local setters = {}
+
+  setters.tint = function(c)
+    assert(type(c) == "table" and #c == 3, "Invalid value for `tint'")
+    shader:send("tint", {
+      (tonumber(c[1]) or 0) / 255,
+      (tonumber(c[2]) or 0) / 255,
+      (tonumber(c[3]) or 0) / 255,
+      1
+    })
+  end
+
+  setters.strength = function(v)
+    shader:send("strength", math.max(0, math.min(1, tonumber(v) or 0)))
+  end
+
+  local defaults = {tint = {255,255,255}, strength = 0.5}
+
+  return moonshine.Effect{
+    name = "desaturate",
+    shader = shader,
+    setters = setters,
+    defaults = defaults
+  }
+end