1 files changed, 55 insertions, 0 deletions
diff --git a/libs/moonshine/pixelate.lua b/libs/moonshine/pixelate.lua
new file mode 100644
index 0000000..42fd76e
--- /dev/null
+++ b/libs/moonshine/pixelate.lua
@@ -0,0 +1,55 @@
+--[[
+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 vec2 size;
+    extern number feedback;
+    vec4 effect(vec4 color, Image tex, vec2 tc, vec2 _)
+    {
+      vec4 c = Texel(tex, tc);
+
+      // average pixel color over 5 samples
+      vec2 scale = love_ScreenSize.xy / size;
+      tc = floor(tc * scale + vec2(.5));
+      vec4 meanc = Texel(tex, tc/scale);
+      meanc += Texel(tex, (tc+vec2( 1.0,  .0))/scale);
+      meanc += Texel(tex, (tc+vec2(-1.0,  .0))/scale);
+      meanc += Texel(tex, (tc+vec2(  .0, 1.0))/scale);
+      meanc += Texel(tex, (tc+vec2(  .0,-1.0))/scale);
+
+      return color * mix(.2*meanc, c, feedback);
+    }
+  ]]
+
+  local setters = {}
+  setters.size = function(v)
+    if type(v) == "number" then v = {v,v} end
+    assert(type(v) == "table" and #v == 2, "Invalid value for `size'")
+    shader:send("size", v)
+  end
+  setters.feedback = function(v)
+    shader:send("feedback", math.min(1, math.max(0, tonumber(v) or 0)))
+  end
+
+  return moonshine.Effect{
+    name = "pixelate",
+    shader = shader,
+    setters = setters,
+    defaults = {size = {5,5}, feedback = 0}
+  }
+end