User:Jholsenback

Organization

Basically, I've been using this area as a scratch pad of sorts. As I complete things, and clean-up I'll probably just add a link here for reference.

Scratch Pad

Change Log Extracts

These are change-log extracts that might be useful with helping to update the documentation. For now they are just in reverse chronological order until I can arrange them in a more useful manner.

Beta 35

• Radiosity maximum_reuse parameter now governs the maximum effective radius of a sample more directly.
• Added "out-of-the-box" transparency support for GIF files.
• Added support for PNG sRGB chunks.

Note: Non-legacy scene default gamma handling for image input files has changed significantly from previous betas, affecting all file formats except OpenEXR, Radiance HDR and (with minor differences) most flavors of PNG; there will be NO corresponding warnings. See below for more detail.

Input image files not carrying unambiguous gamma information will now be assumed to match a common gamma setting, and gamma-adjusted accordingly; this common input file gamma setting can be specified in the scene file using the following syntax:

global_settings {
  file_gamma GAMMA
  }

where GAMMA is either a numeric expression specifying the approximate display gamma for which input files are assumed to be gamma pre-corrected, or the keyword srgb indicating that input files are assumed to match the sRGB standard. (In the latter case, gamma adjustment is applied according to the sRGB standard, instead of approximating with a gamma 2.2 power-law function.) The default setting is sRGB.

Regardless of this global setting, gamma correction is not applied if the image input file is obviously used as a mere data container, such as when immediately used in a height field.

Default gamma handling rules for any image input file can be overridden by specifying file_gamma GAMMA immediately after the file name, e.g.:

image_map {
  jpeg "foobar.jpg" file_gamma 1.8
  interpolate 2
  }

This also applies to contexts where gamma adjustment is not normally applied, e.g. file formats that are defined to be encoded linearly, or files used in height fields, to simplify handling of files not conforming to standards.

Note: Gamma handling for PNG input files has changed as follows in legacy #version 3.6 scenes:

• In the absence of an assumed_gamma statement, non-indexed PNG files with a gAMA chunk (i.e. virtually all PNG files) will appear far brighter than with POV-Ray 3.6
• In the presence of an assumed_gamma 1.0 statement, indexed PNG files (uncommon) will appear darker than with POV-Ray 3.6
• In the presence of an assumed_gamma 2.2 statement, PNG files with a gAMA lower than 2.2 (uncommon) will appear darker than with POV-Ray 3.6
• PNG files with an sRGB chunk but no gAMA chunk may appear significantly different than with POV-Ray 3.6
• PNG files may generally appear slightly different than with POV-Ray 3.6

A warning will be printed in these cases, except for the latter.

Keyword Addition Example

This outlines the steps to add a new keyword to the documentation. In this case deprecated

• first determine where the descriptive passage goes then add it
• update the syntax diagram in the appropriate places
• update the syntax diagram in the Quick Reference
• update the Identifiers and Keywords list (not done yet)

Note: save this until all keyword additions have been identified because it's an alphabetic list in html table form.

• document any other place(s) that it's used
• add a table of contents entry

Links

• The source and notes on the LaTeX markup used in the documentation.