The pxSparkle plug-in generates a sparkle pattern as a ray emitting from a point. The plug-in editor provides options to control the density of the rays, the x,y position from where they are emitted, the brightness (Amount) of rays, as well as other parameters, which is covered specifically in context. Before delving into these parameters however, it is important to understand the pxSparkle, like other PixelFX shaders (pxGradient, pxNoise) generates its own pixels. As well, it has the ability to be applied on top of an image and can blend with the image’s pixels.
When the pxSparkle plug-in is applied to a container without an image, it creates sparkle results. However you can also apply it on a container with an image. In this case, you need to decide whether the sparkle pattern should blend on top of the image or whether it cuts the image. If the Cut Image option is on, the host image is seen only in areas that are brighter than zero. The brighter the sparkle, the more apparent the host image is.
The pxSparkle plug-in can be used as a flare to achieve its effect in a radius (the size of the hot spot). The inner Amount (the brightness of the hot spot) and the radius crops or fades the sparkle radially. You can also so the Speed parameter to set the sparkle in motion.
Transform as texture: This option forces the rendering of the sparkle to ignore the viewmatics - the sparkle is always facing the eye-point. This option is handy when applying the sparkle on top of a hierarchy.
Aspect: This option allows you to set the proportion of the sparkle independently of the texture transformation. Often you stretch textures to get what you want. However when applying the pxSparkle plug-in to a distorted texture, you may want to maintain its roundness. Therefore you can use the Aspect parameter to compensate for the texture distortion.
Angle: This lets you rotate the sparkle without manipulating the texture coordinates. This option is handy when you have a static image on top of which you want to apply a rotating sparkle.
Note: This plug-in is located in: Plugins -> Shader -> PixelFX