1 files changed, 63 insertions, 0 deletions
diff --git a/libs/moonshine/filmgrain.lua b/libs/moonshine/filmgrain.lua
new file mode 100644
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+++ b/libs/moonshine/filmgrain.lua
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+--[[
+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 noisetex = love.image.newImageData(256,256)
+  noisetex:mapPixel(function()
+    local l = love.math.random()
+    return l,l,l,l
+  end)
+  noisetex = love.graphics.newImage(noisetex)
+
+  local shader = love.graphics.newShader[[
+    extern number opacity;
+    extern number size;
+    extern vec2 noise;
+    extern Image noisetex;
+    extern vec2 tex_ratio;
+
+    float rand(vec2 co) {
+      return Texel(noisetex, mod(co * tex_ratio / vec2(size), vec2(1.0))).r;
+    }
+
+    vec4 effect(vec4 color, Image texture, vec2 tc, vec2 _) {
+      return color * Texel(texture, tc) * mix(1.0, rand(tc+vec2(noise)), opacity);
+    }]]
+
+  shader:send("noisetex", noisetex)
+  shader:send("tex_ratio", {love.graphics.getWidth() / noisetex:getWidth(),
+                            love.graphics.getHeight() / noisetex:getHeight()})
+
+  local setters = {}
+  for _,k in ipairs{"opacity", "size"} do
+    setters[k] = function(v) shader:send(k, math.max(0, tonumber(v) or 0)) end
+  end
+
+  local defaults = {opacity = .3, size = 1}
+
+  local draw = function(buffer)
+    shader:send("noise", {love.math.random(), love.math.random()})
+    moonshine.draw_shader(buffer, shader)
+  end
+
+  return moonshine.Effect{
+    name = "filmgrain",
+    draw = draw,
+    setters = setters,
+    defaults = defaults
+  }
+end