[retro-gtk] glsl-filters: Re-add bicubic and sharp filters

[Adrien Plazas <aplazas src gnome org>]

commit b1c3c3ec889160a4a74990ce11b5047868bf114c
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Fri Jan 31 22:53:03 2020 +0500

    glsl-filters: Re-add bicubic and sharp filters
    
    Revert commit fd78cbae0f9f8c49c8dceb2437cdae237bfc7e96.
    
    Also use unix newlines in bicubic.fs and explicitly specify all properties
    in bicubic.filter to avoid warnings.

 retro-gtk/glsl-filters/bicubic.filter |  8 ++++
 retro-gtk/glsl-filters/bicubic.fs     | 90 +++++++++++++++++++++++++++++++++++
 retro-gtk/glsl-filters/sharp.filter   |  7 +++
 retro-gtk/glsl-filters/sharp.fs       | 13 +++++
 retro-gtk/glsl-filters/sharp.vs       | 20 ++++++++
 retro-gtk/retro-gtk.gresource.xml     |  5 ++
 6 files changed, 143 insertions(+)
---
diff --git a/retro-gtk/glsl-filters/bicubic.filter b/retro-gtk/glsl-filters/bicubic.filter
new file mode 100644
index 0000000..6f4c971
--- /dev/null
+++ b/retro-gtk/glsl-filters/bicubic.filter
@@ -0,0 +1,8 @@
+[GLSL Filter]
+Filter=Linear
+Wrap=Border
+Vertex=sharp.vs
+Fragment=bicubic.fs
+Authors=hunterk;
+License=GPL-2.0+;
+URL=https://github.com/hizzlekizzle/quark-shaders/tree/master/Bicubic.shader
diff --git a/retro-gtk/glsl-filters/bicubic.fs b/retro-gtk/glsl-filters/bicubic.fs
new file mode 100644
index 0000000..1c7c689
--- /dev/null
+++ b/retro-gtk/glsl-filters/bicubic.fs
@@ -0,0 +1,90 @@
+#version 150
+
+uniform sampler2D source[];
+uniform vec4 sourceSize[];
+
+in Vertex {
+  vec2 texCoord;
+};
+
+               out vec4 fragColor;
+
+       float weight(float x)
+       {
+           float ax = abs(x);
+           // Mitchel-Netravali coefficients.
+           // Best psychovisual result.
+           const float B = 1.0 / 3.0;
+           const float C = 1.0 / 3.0;
+
+           if (ax < 1.0) {
+               return (
+                   pow(x, 2.0) * (
+                       (12.0 - 9.0 * B - 6.0 * C) * ax +
+                       (-18.0 + 12.0 * B + 6.0 * C)
+                   ) +
+                   (6.0 - 2.0 * B)
+               ) / 6.0;
+
+           } else if ((ax >= 1.0) && (ax < 2.0)) {
+               return (
+                   pow(x, 2.0) * (
+                       (-B - 6.0 * C) * ax +
+                       (6.0 * B + 30.0 * C)
+                   ) +
+                   (-12.0 * B - 48.0 * C) * ax +
+                   (8.0 * B + 24.0 * C)
+               ) / 6.0;
+
+           } else {
+               return 0.0;
+           }
+       }
+
+       vec4 weight4(float x)
+       {
+           return vec4(
+               weight(x + 1.0),
+               weight(x),
+               weight(1.0 - x),
+               weight(2.0 - x));
+       }
+
+       vec3 pixel(float xpos, float ypos)
+       {
+           return texture2D(source[0], vec2(xpos, ypos)).rgb;
+       }
+
+       vec3 line(float ypos, vec4 xpos, vec4 linetaps)
+       {
+           return
+               pixel(xpos.r, ypos) * linetaps.r +
+               pixel(xpos.g, ypos) * linetaps.g +
+               pixel(xpos.b, ypos) * linetaps.b +
+               pixel(xpos.a, ypos) * linetaps.a;
+       }
+
+       void main()
+       {
+           vec2 stepxy = 1.0 / sourceSize[0].xy;
+           vec2 pos = texCoord.xy + stepxy * 0.5;
+           vec2 f = fract(pos / stepxy);
+
+           vec4 linetaps   = weight4(f.x);
+           vec4 columntaps = weight4(f.y);
+
+           // make sure all taps added together is exactly 1.0, otherwise some
+           // (very small) distortion can occur
+           linetaps /= linetaps.r + linetaps.g + linetaps.b + linetaps.a;
+           columntaps /= columntaps.r + columntaps.g + columntaps.b + columntaps.a;
+
+           vec2 xystart = (-1.5 - f) * stepxy + pos;
+           vec4 xpos = vec4(
+               xystart.x,
+               xystart.x + stepxy.x,
+               xystart.x + stepxy.x * 2.0,
+               xystart.x + stepxy.x * 3.0);
+
+               fragColor.a = 1.0;
+           fragColor.rgb = line(xystart.y, xpos, linetaps) * columntaps.r + line(xystart.y + stepxy.y, xpos, 
linetaps) * columntaps.g + line(xystart.y + stepxy.y * 2.0, xpos, linetaps) * columntaps.b + line(xystart.y + 
stepxy.y * 3.0, xpos, linetaps) * columntaps.a;
+       }
diff --git a/retro-gtk/glsl-filters/sharp.filter b/retro-gtk/glsl-filters/sharp.filter
new file mode 100644
index 0000000..cb22335
--- /dev/null
+++ b/retro-gtk/glsl-filters/sharp.filter
@@ -0,0 +1,7 @@
+[GLSL Filter]
+Filter=Nearest
+Wrap=Border
+Vertex=sharp.vs
+Fragment=sharp.fs
+Authors=Adrien Plazas;
+License=GPL-3.0+;
diff --git a/retro-gtk/glsl-filters/sharp.fs b/retro-gtk/glsl-filters/sharp.fs
new file mode 100644
index 0000000..93f7013
--- /dev/null
+++ b/retro-gtk/glsl-filters/sharp.fs
@@ -0,0 +1,13 @@
+#version 150
+
+uniform sampler2D source[];
+
+in Vertex {
+  vec2 texCoord;
+};
+
+out vec4 fragColor;
+
+void main() {
+  fragColor = texture(source[0], texCoord);
+}
diff --git a/retro-gtk/glsl-filters/sharp.vs b/retro-gtk/glsl-filters/sharp.vs
new file mode 100644
index 0000000..cfe4a83
--- /dev/null
+++ b/retro-gtk/glsl-filters/sharp.vs
@@ -0,0 +1,20 @@
+#version 150 core
+
+in vec2 position;
+in vec2 texCoord;
+
+out Vertex {
+  vec2 texCoord;
+} vertexOut;
+
+uniform float relative_aspect_ratio;
+
+void main ()
+{
+  vec2 aspect_ratio = (relative_aspect_ratio > 1.0f) ?
+    vec2 (1.0 / relative_aspect_ratio, 1.0) :
+    vec2 (1.0, relative_aspect_ratio);
+
+  vertexOut.texCoord = texCoord;
+  gl_Position = vec4 (position.xy * aspect_ratio, 0.0, 1.0);
+}
diff --git a/retro-gtk/retro-gtk.gresource.xml b/retro-gtk/retro-gtk.gresource.xml
index f88aa9a..3ca75a1 100644
--- a/retro-gtk/retro-gtk.gresource.xml
+++ b/retro-gtk/retro-gtk.gresource.xml
@@ -1,8 +1,13 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <gresources>
   <gresource prefix="/org/gnome/Retro">
+    <file>glsl-filters/bicubic.filter</file>
+    <file>glsl-filters/bicubic.fs</file>
     <file>glsl-filters/crt-simple.filter</file>
     <file>glsl-filters/crt-simple.fs</file>
     <file>glsl-filters/crt-simple.vs</file>
+    <file>glsl-filters/sharp.filter</file>
+    <file>glsl-filters/sharp.fs</file>
+    <file>glsl-filters/sharp.vs</file>
   </gresource>
 </gresources>