slang-shaders/cubic/shaders/spline36-y.slang
Hyllian cfe2bc9ecf Add lanczos, spline16 and spline36
Three general purpose multipass shaders:
- lanczos3-fast: lanczos with 3-taps;
- spline16-fast: looks like lanczos2 with slightly less ringing;
- spline36-fast: looks like lanczos3 with  slightly less ringing.
2022-08-06 18:12:30 -03:00

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#version 450
/*
Spline36 - PassY - by Hyllian 2022
Adapted from bicubic source shaders below.
Spline36 math sources: https://www.panotools.org/dersch/interpolator/interpolator.html
*/
/*
Copyright (C) 2010 Team XBMC
http://www.xbmc.org
Copyright (C) 2011 Stefanos A.
http://www.opentk.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, 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 XBMC; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
http://www.gnu.org/copyleft/gpl.html
*/
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;
#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 + vec2(0.0001, 0.0001);;
}
#pragma stage fragment
layout(location = 0) in vec2 vTexCoord;
layout(location = 0) out vec4 FragColor;
layout(set = 0, binding = 2) uniform sampler2D Source;
float weight(float x)
{
x = abs(x);
if (x < 1.0)
{
return
(
( ( 13.0/11.0 * x - 453.0/ 209.0 ) * x - 3.0/ 209.0 ) * x + 1.0
);
}
else if ((x >= 1.0) && (x < 2.0))
{
return
(
( ( - 6.0/11.0 * (x-1) + 270.0/ 209.0 ) * (x-1) - 156.0/ 209.0 ) *(x-1)
);
}
else if ((x >= 2.0) && (x < 3.0))
{
return
(
( ( 1.0/11.0 * (x-2) - 45.0/ 209.0 ) * (x-2) + 26.0/ 209.0 ) *(x-2)
);
}
else
{
return 0.0;
}
}
vec3 weight3(float x)
{
return vec3(
weight(x - 1.0),
weight(x),
weight(x + 1.0)
);
}
void main()
{
vec2 ps = params.SourceSize.zw;
vec2 pos = vTexCoord.xy + ps * vec2(0.0, 0.5);
vec2 fp = fract(pos / ps);
vec2 xystart = (-2.5 - fp) * ps + pos;
float xpos = xystart.x + ps.x * 3.0;
vec3 C0 = texture(Source, vec2(xpos, xystart.y )).rgb;
vec3 C1 = texture(Source, vec2(xpos, xystart.y + ps.y )).rgb;
vec3 C2 = texture(Source, vec2(xpos, xystart.y + ps.y * 2.0)).rgb;
vec3 C3 = texture(Source, vec2(xpos, xystart.y + ps.y * 3.0)).rgb;
vec3 C4 = texture(Source, vec2(xpos, xystart.y + ps.y * 4.0)).rgb;
vec3 C5 = texture(Source, vec2(xpos, xystart.y + ps.y * 5.0)).rgb;
vec3 w1 = weight3(-1.0 - fp.y);
vec3 w2 = weight3( 2.0 - fp.y);
float sum = dot( w1, vec3(1)) + dot( w2, vec3(1));
w1 /= sum;
w2 /= sum;
vec3 color = mat3( C0, C1, C2 ) * w1 + mat3( C3, C4, C5) * w2;
FragColor = vec4(color, 1.0);
}