render setting

This setting is a bool setting that specifies if the formula is fully compatible with rendering to disk. It defaults to true, because most formulas are compatible. You only need to set it to false when a formula is not directly compatible.

Formulas are not directly compatible with rendering to disk when they perform most of their calculations in the global section. Such formulas, like the Flame Fractals coloring algorithm, typically use a two-dimensional array equal to the size of the screen to precalculate the fractal.

The disk rendering engine divides images into horizontal strips to reduce memory requirements when calculating large images. If most of the fractal calculations are performed in the global section, these are redone for each strip. Each strip allocates memory for the entire image, and each strip calculates the entire image. Clearly, this is very inefficient.

In formulas that perform most of their calculations in the global section, you must set the render setting to false. This causes Ultra Fractal to render layers that use such a formula in a special mode, where it is rendered just once. This enables Ultra Fractal to render flame fractals correctly.

Effects of setting the render setting to false are:

Layers using the formula are not split into strips when rendering, which ensures that the global section is only executed once.
Layers using the formula are not eligible for multi-threading or network calculations, since this also involves splitting them into parts.
Selecting the Split into tiles option when rendering a fractal using the formula to disk results in a warning message, because this cannot be done efficiently.

Not all formulas that set up a two-dimension array equal to the size of the image in the global section need to set the render setting to false. Formulas that still perform most of their calculations in the per-pixel sections such as the init, loop, and final sections, can benefit from network rendering and multi-threading and will work reasonably well with the default disk render behavior.

Example of a formula that uses the render setting:

global:
  int pixels[#width + 1, #height + 1]
  ; Do all calculations here
final:
  ; Look up pixel color or index value and assign to
  ; #pixel or #color
default:
  title = "My Special Formula"
  render = false