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/posterize.lua | 59 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)
 create mode 100644 libs/moonshine/posterize.lua

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

diff --git a/libs/moonshine/posterize.lua b/libs/moonshine/posterize.lua
new file mode 100644
index 0000000..bc98805
--- /dev/null
+++ b/libs/moonshine/posterize.lua
@@ -0,0 +1,59 @@
+--[[
+Public domain:
+
+Copyright (C) 2017 by Matthias Richter <vrld@vrld.org>
+
+shader based on code by sam hocevar, see
+https://gamedev.stackexchange.com/questions/59797/glsl-shader-change-hue-saturation-brightness
+
+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 number num_bands;
+    vec3 rgb2hsv(vec3 c)
+    {
+      vec4 K = vec4(0.0, -1.0 / 3.0, 2.0 / 3.0, -1.0);
+      vec4 p = mix(vec4(c.bg, K.wz), vec4(c.gb, K.xy), step(c.b, c.g));
+      vec4 q = mix(vec4(p.xyw, c.r), vec4(c.r, p.yzx), step(p.x, c.r));
+
+      float d = q.x - min(q.w, q.y);
+      float e = 1.0e-10;
+      return vec3(abs(q.z + (q.w - q.y) / (6.0 * d + e)), d / (q.x + e), q.x);
+    }
+
+    vec3 hsv2rgb(vec3 c)
+    {
+      vec4 K = vec4(1.0, 2.0 / 3.0, 1.0 / 3.0, 3.0);
+      vec3 p = abs(fract(c.xxx + K.xyz) * 6.0 - K.www);
+      return c.z * mix(K.xxx, clamp(p - K.xxx, 0.0, 1.0), c.y);
+    }
+
+    vec4 effect(vec4 color, Image texture, vec2 tc, vec2 _)
+    {
+      color = Texel(texture, tc);
+      vec3 hsv = floor((rgb2hsv(color.rgb) * num_bands) + vec3(0.5)) / num_bands;
+      return vec4(hsv2rgb(hsv), color.a);
+    }]]
+
+  return moonshine.Effect{
+    name = "posterize",
+    shader = shader,
+    setters = {
+      num_bands = function(v)
+        shader:send("num_bands", math.max(1, tonumber(v) or 1))
+      end
+    },
+    defaults = {num_bands = 3}
+  }
+end
-- 
cgit v1.2.3