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BugFix luma and chroma key

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making alpha filters compatible with alpha fading of media
This commit is contained in:
Bruno Herbelin
2023-12-26 12:04:16 +01:00
parent f610e8ba1e
commit e8daeb5f30
2 changed files with 39 additions and 29 deletions
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rsc/shaders/filters/chromakey.glsl
+10 -2
View File
@@ -42,16 +42,24 @@ void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
vec4 texColor0 = texture(iChannel0, fragCoord.xy / iResolution.xy);
// RGB is alpha-premultiplied : revert
vec4 col = vec4( texColor0.rgb / max(texColor0.a, 0.001), 1.0);
//convert from RGB to YCvCr/YUV
vec4 keyYUV = RGBtoYUV * chromaKey;
vec4 yuv = RGBtoYUV * texColor0;
vec4 yuv = RGBtoYUV * col;
// correction of color
float t = (1. - Tolerance) * 0.2;
float mask = 1.0 - colordistance(yuv.rgb, keyYUV.rgb, vec2(t, t + 0.2));
vec4 col = max(texColor0 - mask * chromaKey, 0.0);
col = max(col - mask * chromaKey, 0.0);
// correction of alpha
t = Threshold * Threshold * 0.2;
col.a -= 1.0 - colordistance(yuv.rgb, keyYUV.rgb, vec2(t, t + 0.25));
// restore texture alpha
col.a *= texColor0.a;
fragColor = col;
}
rsc/shaders/filters/lumakey.glsl
+29 -27
View File
@@ -9,40 +9,42 @@ uniform float Threshold;
uniform float Tolerance;
//float sRGBtoLin( in float v ) {
// // Send this function a decimal sRGB gamma encoded color value
// // between 0.0 and 1.0, and it returns a linearized value.
// if ( v <= 0.04045 ) {
// return v / 12.92;
// } else {
// return pow((( v + 0.055)/1.055),2.4);
// }
//}
float sRGBtoLin( in float v ) {
// Send this function a decimal sRGB gamma encoded color value
// between 0.0 and 1.0, and it returns a linearized value.
if ( v <= 0.04045 ) {
return v / 12.92;
} else {
return pow((( v + 0.055)/1.055),2.4);
}
}
//// returns L* which is "perceptual lightness"
//float lightness ( in vec3 color )
//{
// float Y = 0.2126 * sRGBtoLin(color.r)
// + 0.7152 * sRGBtoLin(color.g)
// + 0.0722 * sRGBtoLin(color.b);
// returns L* which is "perceptual lightness"
float lightness ( in vec3 color )
{
float Y = 0.2126 * sRGBtoLin(color.r)
+ 0.7152 * sRGBtoLin(color.g)
+ 0.0722 * sRGBtoLin(color.b);
// if ( Y <= (216./24389.) ) { // The CIE standard states 0.008856 but 216/24389 is the intent for 0.008856451679036
// Y = Y * (24389./27.); // The CIE standard states 903.3, but 24389/27 is the intent, making 903.296296296296296
// } else {
// Y = pow(Y,(1./3.)) * 116. - 16.;
// }
if ( Y <= (216./24389.) ) { // The CIE standard states 0.008856 but 216/24389 is the intent for 0.008856451679036
Y = Y * (24389./27.); // The CIE standard states 903.3, but 24389/27 is the intent, making 903.296296296296296
} else {
Y = pow(Y,(1./3.)) * 116. - 16.;
}
// return 0.01 * Y;
//}
return 0.01 * Y;
}
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
vec2 fragPos = fragCoord.xy / iResolution.xy;
vec3 RGB = texture(iChannel0, fragPos).rgb;
vec4 texColor0 = texture(iChannel0, fragCoord.xy / iResolution.xy);
// RGB is alpha-premultiplied : revert
texColor0 = vec4( texColor0.rgb / max(texColor0.a, 0.001), texColor0.a);
float L = dot(RGB, vec3(0.299, 0.587, 0.114));
// float L = lightness( RGB );
// modify alpha by the lightness of the image
float L = lightness( texColor0.rgb );
texColor0.a *= smoothstep( Threshold, Threshold + Tolerance * Tolerance, abs(Luminance - L) );
fragColor = vec4( RGB, smoothstep( Threshold, Threshold + Tolerance * Tolerance, abs(Luminance - L) ) );
fragColor = texColor0;
}