slang-shaders/handheld/shaders/lcd1x_nds.slang

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#version 450
/*
lcd1x_nds shader
A slightly tweaked version of lcd3x:
- Original lcd3x code written by Gigaherz and released into the public domain
- Original 'nds_color' code written by hunterk, modified by Pokefan531 and
released into the public domain
Notes:
> Omits LCD 'colour seperation' effect
> Has 'properly' aligned scanlines
> Includes NDS colour correction
> Supports any NDS internal resolution setting
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
#define NDS_SCREEN_HEIGHT 192.0
#define TARGET_GAMMA 1.91
const float INV_DISPLAY_GAMMA = 1.0 / 1.91;
#define CC_LUM 0.89
#define CC_R 0.87
#define CC_G 0.645
#define CC_B 0.73
#define CC_RG 0.10
#define CC_RB 0.10
#define CC_GR 0.255
#define CC_GB 0.17
#define CC_BR -0.125
#define CC_BG 0.255
/*
FRAGMENT SHADER
*/
void main()
{
// Generate LCD grid effect
// > Note the 0.25 pixel offset -> required to ensure that
// scanlines occur *between* pixels
// > Divide pixel coordinate by current scale factor
// (input_video_height / nds_screen_height)
vec2 pixelCoord = vTexCoord.xy * registers.SourceSize.xy;
vec2 angle = 2.0 * PI * ((pixelCoord * NDS_SCREEN_HEIGHT * registers.SourceSize.w) - 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 colour correction
colour.rgb = pow(colour.rgb, vec3(TARGET_GAMMA));
colour.rgb = mat3(CC_R, CC_RG, CC_RB,
CC_GR, CC_G, CC_GB,
CC_BR, CC_BG, CC_B) * (colour.rgb * CC_LUM);
colour.rgb = clamp(pow(colour.rgb, vec3(INV_DISPLAY_GAMMA)), 0.0, 1.0);
// Apply LCD grid effect
colour.rgb = yfactor * xfactor * colour.rgb;
FragColor = vec4(colour.rgb, 1.0);
}