slang-shaders/handheld/shaders/lcd1x.slang
2020-06-29 12:11:21 +01:00

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#version 450
/*
lcd1x shader
A slightly tweaked version of lcd3x, original code written by Gigaherz
and released into the public domain:
> Omits LCD 'colour seperation' effect
> Has 'properly' aligned scanlines
Edited by jdgleaver
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.
*/
#pragma parameter BRIGHTEN_SCANLINES "Brighten Scanlines" 16.0 1.0 32.0 0.5
#pragma parameter BRIGHTEN_LCD "Brighten LCD" 4.0 1.0 12.0 0.1
layout(push_constant) uniform Push
{
float BRIGHTEN_SCANLINES;
float BRIGHTEN_LCD;
vec4 OutputSize;
vec4 OriginalSize;
vec4 SourceSize;
} registers;
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;
/*
VERTEX_SHADER
*/
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;
// Magic Numbers
#define PI 3.141592654
/*
FRAGMENT SHADER
*/
void main()
{
// Generate LCD grid effect
// > Note the 0.25 pixel offset -> required to ensure that
// scanlines occur *between* pixels
vec2 pixelCoord = vTexCoord.xy * registers.SourceSize.xy;
vec2 angle = 2.0 * PI * (pixelCoord - 0.25);
float yfactor = (registers.BRIGHTEN_SCANLINES + sin(angle.y)) / (registers.BRIGHTEN_SCANLINES + 1.0);
float xfactor = (registers.BRIGHTEN_LCD + sin(angle.x)) / (registers.BRIGHTEN_LCD + 1.0);
// Get colour sample
vec3 colour = texture(Source, registers.SourceSize.zw * pixelCoord.xy).rgb;
// Apply LCD grid effect
colour.rgb = yfactor * xfactor * colour.rgb;
FragColor = vec4(colour.rgb, 1.0);
}