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GodotRetro/Screen Shaders/NTSCBasic.shader

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+//SHADER ORIGINALY CREADED BY "keijiro" FROM GITHUB
+//MODIFIED AND PORTED TO GODOT BY AHOPNESS (@ahopness)
+//LICENSE : MIT
+//COMATIBLE WITH : GLES2, GLES3
+//GITHUB LINK : https://github.com/keijiro/KinoTube/
+
+shader_type canvas_item;
+
+const float PI = 3.14159265359;
+
+uniform float _bleeding :hint_range(0, 1) = 0.5;
+uniform float _fringing :hint_range(0, 1) = 0.5;
+uniform float _scanline :hint_range(0, 1) = 0.5;
+uniform bool linearColorSpace = true;
+
+vec3 LinearToGammaSpace (vec3 linRGB){
+	linRGB = max(linRGB, vec3(0, 0, 0));
+	return max(1.055 * pow(linRGB, vec3(0.416666667)) - 0.055, 0);
+}
+vec3 GammaToLinearSpace (vec3 sRGB){
+	return sRGB * (sRGB * (sRGB * 0.305306011 + 0.682171111) + 0.012522878);
+}
+
+vec3 RGB2YIQ(vec3 rgb){
+	rgb = clamp(rgb, 0, 1);
+	if (!linearColorSpace){
+		rgb = LinearToGammaSpace(rgb);
+	}
+	return mat3(vec3(0.299,  0.587,  0.114),
+				vec3(0.596, -0.274, -0.322),
+				vec3(0.211, -0.523,  0.313)) * rgb;
+}
+vec3 YIQ2RGB(vec3 yiq){
+	vec3 rgb = mat3(vec3(1,  0.956,  0.621),
+				    vec3(1, -0.272, -0.647),
+				    vec3(1, -1.106,  1.703)) * yiq;
+	
+	rgb = clamp(rgb, 0, 1);
+	if (!linearColorSpace){
+		rgb = GammaToLinearSpace(rgb);
+	}
+	
+	return rgb;
+}
+
+vec3 SampleYIQ(vec2 uv, float du, sampler2D _MainTex){
+	uv.x += du;
+	return RGB2YIQ(texture(_MainTex, uv).rgb);
+}
+
+void fragment(){
+	float bleedWidth = 0.04 * _bleeding;  // width of bleeding
+	float bleedStep = 2.5 / (1.0 / SCREEN_PIXEL_SIZE).x; // max interval of taps
+	float bleedTaps = ceil(bleedWidth / bleedStep);
+	float bleedDelta = bleedWidth / bleedTaps;
+	float fringeWidth = 0.0025 * _fringing; // width of fringing
+	
+	vec2 uv = FRAGCOORD.xy / (1.0 / SCREEN_PIXEL_SIZE).xy;
+	vec3 yiq = SampleYIQ(uv, 0, SCREEN_TEXTURE);
+	
+        // Bleeding
+        for (float i = 0.0; i < bleedTaps; i++)
+        {
+            yiq.y += SampleYIQ(uv, - bleedTaps * i, SCREEN_TEXTURE).y;
+            yiq.z += SampleYIQ(uv, + bleedTaps * i, SCREEN_TEXTURE).z;
+        }
+        yiq.yz /= bleedTaps + 1.0;
+
+        // Fringing
+        float y1 = SampleYIQ(uv, - fringeWidth, SCREEN_TEXTURE).x;
+        float y2 = SampleYIQ(uv, + fringeWidth, SCREEN_TEXTURE).x;
+        yiq.yz += y2 - y1;
+
+        // Scanline
+        float scan = sin(uv.y * 500.0 * PI);
+        scan = mix(1.0, (scan + 1.0) / 2.0, _scanline);
+
+        COLOR =  vec4(YIQ2RGB(yiq * scan), 1);
+}