From 62ff5245c26c305e35a2903cc64a60cb20718e96 Mon Sep 17 00:00:00 2001
From: Indrajith K L
Date: Sun, 27 Feb 2022 01:15:31 +0530
Subject: Initial Commit

* ECS - In-Progress
* GameStates - Skeleton Implemented
* Library Integrations - Completed
* Levels - In-Progress
---
 libs/moonshine/crt.lua | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 libs/moonshine/crt.lua

(limited to 'libs/moonshine/crt.lua')

diff --git a/libs/moonshine/crt.lua b/libs/moonshine/crt.lua
new file mode 100644
index 0000000..9b73799
--- /dev/null
+++ b/libs/moonshine/crt.lua
@@ -0,0 +1,79 @@
+--[[
+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)
+  -- Barrel distortion adapted from Daniel Oaks (see commit cef01b67fd)
+  -- Added feather to mask out outside of distorted texture
+  local distortionFactor
+  local shader = love.graphics.newShader[[
+    extern vec2 distortionFactor;
+    extern vec2 scaleFactor;
+    extern number feather;
+
+    vec4 effect(vec4 color, Image tex, vec2 uv, vec2 px) {
+      // to barrel coordinates
+      uv = uv * 2.0 - vec2(1.0);
+
+      // distort
+      uv *= scaleFactor;
+      uv += (uv.yx*uv.yx) * uv * (distortionFactor - 1.0);
+      number mask = (1.0 - smoothstep(1.0-feather,1.0,abs(uv.x)))
+                  * (1.0 - smoothstep(1.0-feather,1.0,abs(uv.y)));
+
+      // to cartesian coordinates
+      uv = (uv + vec2(1.0)) / 2.0;
+
+      return color * Texel(tex, uv) * mask;
+    }
+  ]]
+
+  local setters = {}
+
+  setters.distortionFactor = function(v)
+    assert(type(v) == "table" and #v == 2, "Invalid value for `distortionFactor'")
+    distortionFactor = {unpack(v)}
+    shader:send("distortionFactor", v)
+  end
+
+  setters.x = function(v) setters.distortionFactor{v, distortionFactor[2]} end
+  setters.y = function(v) setters.distortionFactor{distortionFactor[1], v} end
+
+  setters.scaleFactor = function(v)
+    if type(v) == "table" and #v == 2 then
+      shader:send("scaleFactor", v)
+    elseif type(v) == "number" then
+      shader:send("scaleFactor", {v,v})
+    else
+      error("Invalid value for `scaleFactor'")
+    end
+  end
+
+  setters.feather = function(v) shader:send("feather", v) end
+
+  local defaults = {
+    distortionFactor = {1.06, 1.065},
+    feather = 0.02,
+    scaleFactor = 1,
+  }
+
+  return moonshine.Effect{
+    name = "crt",
+    shader = shader,
+    setters = setters,
+    defaults = defaults
+  }
+end
-- 
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