add scanline-fract shader

misc/scanline-fract.slang

@@ -0,0 +1,70 @@
+#version 450
+
+// Super-basic scanline shader
+// (looks bad at non-integer scales)
+// by hunterk
+// license: public domain
+
+layout(push_constant) uniform Push
+{
+	vec4 SourceSize;
+	vec4 OriginalSize;
+	vec4 OutputSize;
+	uint FrameCount;
+	float THICKNESS;
+	float DARKNESS;
+	float BRIGHTBOOST;
+} params;
+
+#pragma parameter THICKNESS "Scanline Thickness" 2.0 1.0 12.0 1.0
+#pragma parameter DARKNESS "Scanline Darkness" 0.50 0.0 1.0 0.05
+#pragma parameter BRIGHTBOOST "Scanline Boost Bright" 1.1 1.0 1.2 0.1
+
+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;
+
+vec3 RGBtoYIQ(vec3 RGB){
+	const mat3 yiqmat = mat3(
+		0.2989, 0.5870, 0.1140,
+		0.5959, -0.2744, -0.3216,
+		0.2115, -0.5229, 0.3114);
+	return RGB * yiqmat;
+}
+
+vec3 YIQtoRGB(vec3 YIQ){
+	const mat3 rgbmat = mat3(
+		1.0, 0.956, 0.6210,
+		1.0, -0.2720, -0.6474,
+		1.0, -1.1060, 1.7046);
+	return YIQ * rgbmat;
+}
+
+void main()
+{
+	float lines = fract(vTexCoord.y * params.SourceSize.y);
+	float scale_factor = floor((params.OutputSize.y / params.SourceSize.y) + 0.4999);
+	vec4 screen = texture(Source, vTexCoord);
+	screen.rgb = RGBtoYIQ(screen.rgb);
+	screen.r *= params.BRIGHTBOOST;
+	screen.rgb = YIQtoRGB(screen.rgb);
+
+	FragColor = (lines > (1.0 / scale_factor * params.THICKNESS)) ? screen : screen * vec4(1.0 - params.DARKNESS);
+}