/*{
"CATEGORIES": [
"Masking",
"Color Effect",
"Utility"
],
"CREDIT": "by zoidberg",
"DESCRIPTION": "Takes a mask image and applies it to the input image's alpha channel.",
"INPUTS": [
{
"NAME": "inputImage",
"TYPE": "image"
},
{
"LABEL": "mask image",
"NAME": "maskImage",
"TYPE": "image"
},
{
"DEFAULT": 0,
"LABEL": "mask size mode",
"LABELS": [
"Fit",
"Fill",
"Stretch",
"Copy"
],
"NAME": "maskSizingMode",
"TYPE": "long",
"VALUES": [
0,
1,
2,
3
]
},
{
"DEFAULT": 0,
"MAX": 1,
"MIN": -1,
"NAME": "bright",
"TYPE": "float"
},
{
"DEFAULT": 1,
"MAX": 4,
"MIN": -4,
"NAME": "contrast",
"TYPE": "float"
},
{
"DEFAULT": 2,
"LABEL": "Alpha Mode",
"LABELS": [
"Additive",
"Multiply",
"Replace"
],
"NAME": "alphaMode",
"TYPE": "long",
"VALUES": [
0,
1,
2
]
},
{
"DEFAULT": 0,
"NAME": "applyAlpha",
"TYPE": "bool"
}
],
"ISFVSN": "2"
}
*/
const vec4 lumcoeff = vec4(0.299, 0.587, 0.114, 0.0);
// 'a' and 'b' are rects (x and y are the originx, z and w are the width and height)
// 'm' is the sizing mode as described above (fit/fill/stretch/copy)
vec4 RectThatFitsRectInRect(vec4 a, vec4 b, int m);
void main() {
vec4 srcPixel = IMG_THIS_PIXEL(inputImage);
// get the rect of the mask image after it's been resized according to the passed sizing mode. this is in pixel coords relative to the rendering space!
//vec4 rectOfResizedMaskImage = RectThatFitsRectInRect(vec4(0.0, 0.0, _maskImage_imgRect.z, _maskImage_imgRect.w), vec4(0,0,RENDERSIZE.x,RENDERSIZE.y), maskSizingMode);
vec4 rectOfResizedMaskImage = RectThatFitsRectInRect(vec4(0.0, 0.0, IMG_SIZE(maskImage).x, IMG_SIZE(maskImage).y), vec4(0,0,RENDERSIZE.x,RENDERSIZE.y), maskSizingMode);
// i know the pixel coords of this frag in the render space- convert this to NORMALIZED texture coords for the resized mask image
vec2 normMaskSrcCoord;
normMaskSrcCoord.x = (gl_FragCoord.x-rectOfResizedMaskImage.x)/rectOfResizedMaskImage.z;
normMaskSrcCoord.y = (gl_FragCoord.y-rectOfResizedMaskImage.y)/rectOfResizedMaskImage.w;
// get the color of the pixel from the mask image for these normalized coords
vec4 tmpColorA = IMG_NORM_PIXEL(maskImage, normMaskSrcCoord);
// apply bright/contrast to this pixel value
vec4 tmpColorB = tmpColorA + vec4(bright, bright, bright, 0.0);
tmpColorA.rgb = ((vec3(2.0) * (tmpColorB.rgb - vec3(0.5))) * vec3(contrast) / vec3(2.0)) + vec3(0.5);
tmpColorA.a = ((2.0 * (tmpColorB.a - 0.5)) * abs(contrast) / 2.0) + 0.5;
// get the luminance of this pixel value: this will be the new alpha for the source pixel
float luminance = dot(tmpColorA,lumcoeff);
// if the alpha mode isn't replacing, add or multiply now
// (this makes it possible to stack multiple mask FX or preserve alpha from input)
if (alphaMode == 0) {
luminance = luminance + srcPixel.a;
}
else if (alphaMode == 1) {
luminance = luminance * srcPixel.a;
}
if (applyAlpha)
gl_FragColor = vec4(luminance*srcPixel.r, luminance*srcPixel.g, luminance*srcPixel.b, 1.0);
else
gl_FragColor = vec4(srcPixel.r, srcPixel.g, srcPixel.b, luminance);
}
// rect that fits 'a' in 'b' using sizing mode 'm'
vec4 RectThatFitsRectInRect(vec4 a, vec4 b, int m) {
float bAspect = b.z/b.w;
float aAspect = a.z/a.w;
if (aAspect==bAspect) {
return b;
}
vec4 returnMe = vec4(0.0);
// fit
if (m==0) {
// if the rect i'm trying to fit stuff *into* is wider than the rect i'm resizing
if (bAspect > aAspect) {
returnMe.w = b.w;
returnMe.z = returnMe.w * aAspect;
}
// else if the rect i'm resizing is wider than the rect it's going into
else if (bAspect < aAspect) {
returnMe.z = b.z;
returnMe.w = returnMe.z / aAspect;
}
else {
returnMe.z = b.z;
returnMe.w = b.w;
}
returnMe.x = (b.z-returnMe.z)/2.0+b.x;
returnMe.y = (b.w-returnMe.w)/2.0+b.y;
}
// fill
else if (m==1) {
// if the rect i'm trying to fit stuff *into* is wider than the rect i'm resizing
if (bAspect > aAspect) {
returnMe.z = b.z;
returnMe.w = returnMe.z / aAspect;
}
// else if the rect i'm resizing is wider than the rect it's going into
else if (bAspect < aAspect) {
returnMe.w = b.w;
returnMe.z = returnMe.w * aAspect;
}
else {
returnMe.z = b.z;
returnMe.w = b.w;
}
returnMe.x = (b.z-returnMe.z)/2.0+b.x;
returnMe.y = (b.w-returnMe.w)/2.0+b.y;
}
// stretch
else if (m==2) {
returnMe = vec4(b.x, b.y, b.z, b.w);
}
// copy
else if (m==3) {
returnMe.z = float(int(a.z));
returnMe.w = float(int(a.w));
returnMe.x = float(int((b.z-returnMe.z)/2.0+b.x));
returnMe.y = float(int((b.w-returnMe.w)/2.0+b.y));
}
return returnMe;
}
