add GritsScanlines shader and preset

crt/GritsScanlines.slangp

@@ -0,0 +1,18 @@
+shaders = 2
+
+shader0 = shaders/GritsScanlines/GritsScanlines.slang
+filter_linear0 = true
+scale_type0 = source
+scale_x0 = 1.0
+scale_y0 = 4.0
+
+shader1 = ../stock.slang
+filter_linear1 = true
+
+textures = "scanlines_LUT;color_LUT;luminance_LUT"
+scanlines_LUT = shaders/GritsScanlines/Scanline-LUT-4px.png
+scanlines_LUT_linear = false
+color_LUT = shaders/GritsScanlines/trinitron_color.png
+color_LUT_linear = true
+luminance_LUT = shaders/GritsScanlines/Fake-Self-Illumination.png
+luminance_LUT_linear = true

crt/shaders/GritsScanlines/GritsScanlines.slang

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+#version 450
+
+// GritsScanlines by torridgristle
+// license: public domain (https://forums.libretro.com/t/lightweight-lut-based-scanline-glow-concept-prototype-glsl/18336/7)
+
+layout(push_constant) uniform Push
+{
+	vec4 SourceSize;
+	vec4 OriginalSize;
+	vec4 OutputSize;
+	uint FrameCount;
+   float ScanlinesOpacity;
+   float GammaCorrection;
+} params;
+
+#pragma parameter ScanlinesOpacity "Scanline Opacity" 0.9 0.0 1.0 0.05
+#pragma parameter GammaCorrection "Gamma Correction" 1.2 0.5 2.0 0.1
+
+#define ScanlinesOpacity params.ScanlinesOpacity
+#define GammaCorrection params.GammaCorrection
+
+//#define LuminanceDawnbringer
+#define LuminanceLUT
+//#define TrinitronColors
+
+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;
+layout(set = 0, binding = 3) uniform sampler2D luminance_LUT;
+layout(set = 0, binding = 4) uniform sampler2D color_LUT;
+layout(set = 0, binding = 5) uniform sampler2D scanlines_LUT;
+
+#ifdef LuminanceLUT
+
+#define LUT_SizeLum 16.0
+
+	// Code taken from RetroArch's LUT shader
+float luminancelut(vec4 org)
+{
+	vec4 imgColorLum = org;
+	float redLum = ( imgColorLum.r * (LUT_SizeLum - 1.0) + 0.4999 ) / (LUT_SizeLum * LUT_SizeLum);
+	float greenLum = ( imgColorLum.g * (LUT_SizeLum - 1.0) + 0.4999 ) / LUT_SizeLum;
+	float blue1Lum = (floor( imgColorLum.b  * (LUT_SizeLum - 1.0) ) / LUT_SizeLum) + redLum;
+	float blue2Lum = (ceil( imgColorLum.b  * (LUT_SizeLum - 1.0) ) / LUT_SizeLum) + redLum;
+	float mixerLum = clamp(max((imgColorLum.b - blue1Lum) / (blue2Lum - blue1Lum), 0.0), 0.0, 32.0);
+	float color1Lum = texture(luminance_LUT, vec2( blue1Lum, greenLum )).x;
+	float color2Lum = texture(luminance_LUT, vec2( blue2Lum, greenLum )).x;
+	return mix(color1Lum, color2Lum, mixerLum);
+}
+#endif
+
+#ifdef TrinitronColors
+
+#define LUT_SizeTrinitron 32.0
+
+vec4 TrinitronD50(vec4 org)
+{
+	vec4 imgColorTrinitron = org;
+	float redTrinitron = ( imgColorTrinitron.r * (LUT_SizeTrinitron - 1.0) + 0.4999 ) / (LUT_SizeTrinitron * LUT_SizeTrinitron);
+	float greenTrinitron = ( imgColorTrinitron.g * (LUT_SizeTrinitron - 1.0) + 0.4999 ) / LUT_SizeTrinitron;
+	float blue1Trinitron = (floor( imgColorTrinitron.b  * (LUT_SizeTrinitron - 1.0) ) / LUT_SizeTrinitron) + redTrinitron;
+	float blue2Trinitron = (ceil( imgColorTrinitron.b  * (LUT_SizeTrinitron - 1.0) ) / LUT_SizeTrinitron) + redTrinitron;
+	float mixerTrinitron = clamp(max((imgColorTrinitron.b - blue1Trinitron) / (blue2Trinitron - blue1Trinitron), 0.0), 0.0, 32.0);
+	vec4 color1Trinitron = texture(color_LUT, vec2( blue1Trinitron, greenTrinitron ));
+	vec4 color2Trinitron = texture(color_LUT, vec2( blue2Trinitron, greenTrinitron ));
+	vec4 fragColorTrinitron = mix(color1Trinitron, color2Trinitron, mixerTrinitron);
+	return vec4(pow(fragColorTrinitron.rgb,vec3(GammaCorrection,GammaCorrection,GammaCorrection)),1.0);
+} 
+#endif
+
+void main()
+{
+//Source Image
+	vec4 org = texture(Source, vTexCoord);
+   
+#ifdef LuminanceLUT
+// Use a 3DLUT instead of an equation so that it can use any arbitrary mess you can come up with.
+	float luminance = luminancelut(org);
+#elif defined LuminanceDawnbringer
+// Dawnbringer's brightness equation from Dawnbringer's Toolbox scripts for Grafx2
+	float luminance = sqrt(org.r*org.r*0.0676 + org.g*org.g*0.3025 + org.b*org.b*0.0361) * 1.5690256395005606;
+#else
+// Plain, standard, fine; slightly faster
+	float luminance = ((0.299*org.r) + (0.587*org.g) + (0.114*org.b));
+#endif
+
+// Don't let it exceed 1.0
+	luminance = clamp(luminance, 0.0, 1.0);
+
+// Scanline Mapping, based on the Phosphor LUT shader's method of tiling a texture over the screen
+	vec2 LUTeffectiveCoord = vec2(luminance,fract(vTexCoord.y*params.SourceSize.y));
+
+// Scanline Layer
+	vec4 screen = texture(scanlines_LUT, LUTeffectiveCoord);
+
+// Output multiplying the scanlines into the original image, with control over opacity
+#ifdef TrinitronColors
+	org = TrinitronD50(org);
+#endif
+	FragColor = ((screen*ScanlinesOpacity)+(1.0 - ScanlinesOpacity)) * (org);
+}