Format
filter(type="bloom", ...)
Args
threshold: Color threshold for bloomsize: Blur radius of bloom effect (see Gaussian blur)offset: Growth/outline radius of bloom effect before bluralpha: Opacity of effect (default is 255, max opacity)
Post-processing effect that makes bright colors look like they’re a strong light source, spreading their light additively to other nearby pixels. This is a complex effect that involves multiple shader passes. For both performance and visual reasons, it is usually best applied to an entire plane rather than to individual objects.
The color threshold determines which pixels this effect applies to. If any of the red, green, or blue components of the pixel are greater than the same component for the threshold, that pixel will bloom. The blooming pixels then have their colors spread outward to create a glow that gets added to the original image.
The offset and size parameters are used to control the glow effect. They work the same as they do in the drop shadow filter: offset causes the light to grow outwards, and a blur of size is then applied to soften it. Often just using a blur alone will produce a pleasing effect. By playing with these two values you can make the bloom effect appear differently.
The alpha value is applied to any light contributions from bloomed pixels that get added to the original image, so values lower than 255 can make the effect less pronounced. This can be very useful if you choose to animate the filter.