From 6223237f5a127fb2a59c16da33c0a3a9418621d6 Mon Sep 17 00:00:00 2001
From: hunterk <hunter_kaller@yahoo.com>
Date: Thu, 20 Oct 2016 11:55:05 -0500
Subject: [PATCH] add lanczos16 shader and preset

---
 windowed/lanczos16.slangp        |   4 ++
 windowed/shaders/lanczos16.slang | 118 +++++++++++++++++++++++++++++++
 2 files changed, 122 insertions(+)
 create mode 100644 windowed/lanczos16.slangp
 create mode 100644 windowed/shaders/lanczos16.slang

diff --git a/windowed/lanczos16.slangp b/windowed/lanczos16.slangp
new file mode 100644
index 0000000..b247544
--- /dev/null
+++ b/windowed/lanczos16.slangp
@@ -0,0 +1,4 @@
+shaders = 1
+
+shader0 = shaders/lanczos16.slang
+filter_linear0 = false
\ No newline at end of file
diff --git a/windowed/shaders/lanczos16.slang b/windowed/shaders/lanczos16.slang
new file mode 100644
index 0000000..a30c6cd
--- /dev/null
+++ b/windowed/shaders/lanczos16.slang
@@ -0,0 +1,118 @@
+#version 450
+
+/*
+
+   Copyright (C) 2007 guest(r) - guest.r@gmail.com
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License
+   as published by the Free Software Foundation; either version 2
+   of the License, or (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+
+ */
+
+layout(push_constant) uniform Push
+{
+	vec4 SourceSize;
+	vec4 OriginalSize;
+	vec4 OutputSize;
+	uint FrameCount;
+} params;
+
+layout(std140, set = 0, binding = 0) uniform UBO
+{
+	mat4 MVP;
+} global;
+
+const float     floatpi     = 1.5707963267948966192313216916398;
+const float         pi     = 3.1415926535897932384626433832795;
+
+vec4 l(vec4 x)
+{
+   vec4 res;
+
+   res = (x==vec4(0.0, 0.0, 0.0, 0.0)) ?  vec4(pi*floatpi)  :  sin(x*floatpi)*sin(x*pi)/(x*x);
+
+   return res;
+}
+
+#pragma stage vertex
+layout(location = 0) in vec4 Position;
+layout(location = 1) in vec2 TexCoord;
+layout(location = 0) out vec2 vTexCoord;
+layout(location = 1) out vec4 t1;
+layout(location = 2) out vec4 t2;
+layout(location = 3) out vec4 t3;
+layout(location = 4) out vec4 t4;
+
+void main()
+{
+   gl_Position = global.MVP * Position;
+   vTexCoord = TexCoord * 1.000001;
+   vec2 ps = params.SourceSize.zw;
+   float dx = ps.x;
+   float dy = ps.y;
+   
+   t1 = vTexCoord.xxyy + vec4(   -dx,    0.0,    -dy,    0.0);
+   t2 = vTexCoord.xxyy + vec4(    dx, 2.0*dx,    -dy,    0.0);
+   t3 = vTexCoord.xxyy + vec4(   -dx,    0.0,     dy, 2.0*dy);
+   t4 = vTexCoord.xxyy + vec4(    dx, 2.0*dx,     dy, 2.0*dy);
+}
+
+#pragma stage fragment
+layout(location = 0) in vec2 vTexCoord;
+layout(location = 1) in vec4 t1;
+layout(location = 2) in vec4 t2;
+layout(location = 3) in vec4 t3;
+layout(location = 4) in vec4 t4;
+layout(location = 0) out vec4 FragColor;
+layout(set = 0, binding = 2) uniform sampler2D Source;
+
+void main()
+{
+   mat4x3 pix;
+   vec2 fraction = fract(vTexCoord*params.SourceSize.xy);
+
+   // calculating texel weights
+
+   vec4 abcd, pqrs;
+
+   abcd = l(vec4(1+fraction.x, fraction.x, 1-fraction.x, 2-fraction.x));
+   pqrs = l(vec4(1+fraction.y, fraction.y, 1-fraction.y, 2-fraction.y));
+
+   // reading the texels
+
+   vec3 c00 = texture(Source, t1.xz).xyz;
+   vec3 c10 = texture(Source, t1.yz).xyz;
+   vec3 c20 = texture(Source, t2.xz).xyz;
+   vec3 c30 = texture(Source, t2.yz).xyz;
+   vec3 c01 = texture(Source, t1.xw).xyz;
+   vec3 c11 = texture(Source, vTexCoord).xyz;
+   vec3 c21 = texture(Source, t2.xw).xyz;
+   vec3 c31 = texture(Source, t2.yw).xyz;
+   vec3 c02 = texture(Source, t3.xz).xyz;
+   vec3 c12 = texture(Source, t3.yz).xyz;
+   vec3 c22 = texture(Source, t4.xz).xyz;
+   vec3 c32 = texture(Source, t4.yz).xyz;
+   vec3 c03 = texture(Source, t3.xw).xyz;
+   vec3 c13 = texture(Source, t3.yw).xyz;
+   vec3 c23 = texture(Source, t4.xw).xyz;
+   vec3 c33 = texture(Source, t4.yw).xyz;
+
+   pix[0] = mat4x3(-c00, c10, c20, -c30) * abcd;
+   pix[1] = mat4x3( c01, c11, c21,  c31) * abcd;
+   pix[2] = mat4x3( c02, c12, c22,  c32) * abcd;
+   pix[3] = mat4x3(-c03, c13, c23, -c33) * abcd;
+
+   // final sum and weight normalization
+   FragColor = vec4(((pix * pqrs))/((dot(abcd, vec4(1.0))*dot(pqrs, vec4(1.0)))-2*(abcd.x+abcd.w)*(pqrs.x+pqrs.w)),1);
+}
\ No newline at end of file