From 027733b845c4e59acaca89528ef787b89040b4c4 Mon Sep 17 00:00:00 2001
From: aliaspider <aliaspider@gmail.com>
Date: Thu, 5 Apr 2018 05:19:13 +0100
Subject: [PATCH] add reverse-aa.

---
 anti-aliasing/reverse-aa.slangp        |   7 ++
 anti-aliasing/shaders/reverse-aa.slang | 108 +++++++++++++++++++++++++
 xbrz/shaders/xbrz-freescale.slang      |   2 -
 3 files changed, 115 insertions(+), 2 deletions(-)
 create mode 100644 anti-aliasing/reverse-aa.slangp
 create mode 100644 anti-aliasing/shaders/reverse-aa.slang

diff --git a/anti-aliasing/reverse-aa.slangp b/anti-aliasing/reverse-aa.slangp
new file mode 100644
index 0000000..5908be8
--- /dev/null
+++ b/anti-aliasing/reverse-aa.slangp
@@ -0,0 +1,7 @@
+shaders = 1
+
+shader0 = shaders/reverse-aa.slang
+filter_linear0 = false
+scale_type0 = source
+scale0 = 2.0
+
diff --git a/anti-aliasing/shaders/reverse-aa.slang b/anti-aliasing/shaders/reverse-aa.slang
new file mode 100644
index 0000000..c4b6318
--- /dev/null
+++ b/anti-aliasing/shaders/reverse-aa.slang
@@ -0,0 +1,108 @@
+#version 450
+
+/*
+   Reverse Antialiasing Shader
+
+   Adapted from the C source (see Copyright below) to shader
+   cg language by Hyllian/Jararaca - sergiogdb@gmail.com
+
+   This shader works best in 2x scale.
+
+*/
+
+/*
+ *
+ *  Copyright (c) 2012, Christoph Feck <christoph@maxiom.de>
+ *  All Rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions are met:
+ *
+ *    * Redistributions of source code must retain the above copyright notice,
+ *      this list of conditions and the following disclaimer.
+ *
+ *    * Redistributions in binary form must reproduce the above copyright
+ *      notice, this list of conditions and the following disclaimer in the
+ *      documentation and/or other materials provided with the distribution.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ *  POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+
+#pragma parameter REVERSEAA_SHARPNESS "ReverseAA Sharpness" 2.0 0.0 10.0 0.01
+
+#ifdef PARAMETER_UNIFORM
+uniform float REVERSEAA_SHARPNESS;
+#else
+#define REVERSEAA_SHARPNESS 2.0
+#endif
+
+layout(push_constant) uniform Push
+{
+	vec4 SourceSize;
+	vec4 OutputSize;
+} params;
+
+layout(std140, set = 0, binding = 0) uniform UBO
+{
+	mat4 MVP;
+} global;
+
+#pragma stage vertex
+layout(location = 0) in vec4 Position;
+layout(location = 1) in vec2 TexCoord;
+layout(location = 0) out vec2 vTexCoord;
+
+void main()
+{
+   gl_Position = global.MVP * Position;
+   vTexCoord = TexCoord;
+}
+
+#pragma stage fragment
+layout(location = 0) in vec2 vTexCoord;
+layout(location = 0) out vec4 FragColor;
+layout(set = 0, binding = 2) uniform sampler2D Source;
+
+#define P(x,y) texture(Source, coord + params.SourceSize.zw * vec2(x, y)).rgb
+
+vec3 res2x(vec3 pre2, vec3 pre1, vec3 px, vec3 pos1, vec3 pos2)
+{
+    vec3 t, m;
+    mat4x3 pre = mat4x3(pre2, pre1,   px, pos1);
+    mat4x3 pos = mat4x3(pre1,   px, pos1, pos2);
+    mat4x3  df = pos - pre;
+
+    m = 0.5 - abs(px - 0.5);
+    m = REVERSEAA_SHARPNESS * min(m, min(abs(df[1]), abs(df[2])));
+    t = (7 * (df[1] + df[2]) - 3 * (df[0] + df[3])) / 16;
+    t = clamp(t, -m, m);
+
+    return t;
+}
+
+#define P(x,y) texture(Source, coord + params.SourceSize.zw * vec2(x, y)).rgb
+
+void main()
+{
+   vec2 pos = fract(vTexCoord * params.SourceSize.xy) - vec2(0.5, 0.5);
+   vec2 coord = vTexCoord - pos * params.SourceSize.zw;
+
+   vec3 E = P( 0, 0);
+   vec3 _tx = res2x(P(-2,0), P(-1,0), E, P(1,0), P(2,0)) * pos.x;
+   vec3 _ty = res2x(P(0,-2), P(0,-1), E, P(0,1), P(0,2)) * pos.y;
+   vec3 res = clamp(E + 2.0*(_tx + _ty), 0.0, 1.0);
+
+   FragColor = vec4(res, 1.0);
+}
diff --git a/xbrz/shaders/xbrz-freescale.slang b/xbrz/shaders/xbrz-freescale.slang
index 5b13693..8e17522 100644
--- a/xbrz/shaders/xbrz-freescale.slang
+++ b/xbrz/shaders/xbrz-freescale.slang
@@ -103,8 +103,6 @@ void main()
 {
    gl_Position = global.MVP * Position;
    vTexCoord = TexCoord;
-   
-vec2 ps = vec2(params.SourceSize.z, params.SourceSize.w);
 }
 
 #pragma stage fragment