Difference between revisions of "Reference:Version Directive"
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<p class="Note"><strong>Note:</strong> There should be a semi-colon after the float expression in a <code>#version</code> directive. This semi-colon is introduced in POV-Ray version 3.1. If omitted, it generates a warning and some macros may not work | <p class="Note"><strong>Note:</strong> There should be a semi-colon after the float expression in a <code>#version</code> directive. This semi-colon is introduced in POV-Ray version 3.1. If omitted, it generates a warning and some macros may not work | ||
properly.</p> | properly.</p> | ||
− | <p>Additionally you may use the <code>Version=</code><em>n.n</em> option or the <code>+MV</code><em>n.n</em> switch to establish the <em>initial</em> setting. See <!--<linkto "Language Version">Language Version</linkto>--->[[ | + | <p>Additionally you may use the <code>Version=</code><em>n.n</em> option or the <code>+MV</code><em>n.n</em> switch to establish the <em>initial</em> setting. See <!--<linkto "Language Version">Language Version</linkto>--->[[Reference:Scene Parsing Options#Language Version|Language Version]] for details. For example, one feature introduced in 2.0 that was incompatible with any 1.0 scene files is the parsing of float expressions. Using <code>#version 1.0</code> turns off expression parsing as well as many warning messages so that nearly all 1.0 files will still work. Naturally the default setting for this option is <code>#version 3.5</code>.</p> |
<p class="Note"><strong>Note:</strong> Some obsolete or re-designed features <em>are totally unavailable in the current version of POV-Ray REGARDLESS OF THE VERSION SETTING.</em> Details on these features are noted throughout this documentation.</p> | <p class="Note"><strong>Note:</strong> Some obsolete or re-designed features <em>are totally unavailable in the current version of POV-Ray REGARDLESS OF THE VERSION SETTING.</em> Details on these features are noted throughout this documentation.</p> | ||
<p>The built-in float identifier <code>version</code> contains the current setting of the version compatibility option. See | <p>The built-in float identifier <code>version</code> contains the current setting of the version compatibility option. See | ||
− | Float Expressions: [[ | + | Float Expressions: [[Reference:Numeric Expressions#Built-in Variables|:Float, built-in variables|Built-in Variables]]. Together with the built-in <code>version</code> identifier the <code>#version</code> directive allows you to save and restore the previous values of this compatibility setting. The new <code>#local</code> identifier option is especially useful here. For example, suppose <code>mystuff.inc</code> is in version 1 format. At the top of the file you could put:</p> |
<pre> | <pre> | ||
#local Temp_Vers = version; // Save previous value | #local Temp_Vers = version; // Save previous value |
Revision as of 19:45, 15 March 2012
As POV-Ray has evolved from version 1.0 through 3.6 we have made every effort to maintain some amount of backwards compatibility with earlier versions. Some old or obsolete features can be handled directly without any special consideration by the user. Some old or obsolete features can no longer be handled at all. However some old features can still be
used if you warn POV-Ray that this is an older scene. The #version
directive can be used to switch version compatibility to different setting several times throughout a scene file. The syntax is:
VERSION_DIRECTIVE: #version FLOAT;
Note: There should be a semi-colon after the float expression in a #version
directive. This semi-colon is introduced in POV-Ray version 3.1. If omitted, it generates a warning and some macros may not work
properly.
Additionally you may use the Version=
n.n option or the +MV
n.n switch to establish the initial setting. See Language Version for details. For example, one feature introduced in 2.0 that was incompatible with any 1.0 scene files is the parsing of float expressions. Using #version 1.0
turns off expression parsing as well as many warning messages so that nearly all 1.0 files will still work. Naturally the default setting for this option is #version 3.5
.
Note: Some obsolete or re-designed features are totally unavailable in the current version of POV-Ray REGARDLESS OF THE VERSION SETTING. Details on these features are noted throughout this documentation.
The built-in float identifier version
contains the current setting of the version compatibility option. See
Float Expressions: Built-in Variables. Together with the built-in version
identifier the #version
directive allows you to save and restore the previous values of this compatibility setting. The new #local
identifier option is especially useful here. For example, suppose mystuff.inc
is in version 1 format. At the top of the file you could put:
#local Temp_Vers = version; // Save previous value #version 1.0; // Change to 1.0 mode ... // Version 1.0 stuff goes here... #version Temp_Vers; // Restore previous version
As of version 3.7, there has been a requirement implemented. In order to obtain full version 3.7
functionality, you MUST specify the #version 3.7
directive in your scene file. Prior to a #version
directive appearing, the version defaults to 3.62. Additionally, if the first #version
appears after any other declaration, or a #version
directive does not appear at all, a post-parse warning is issued.
Warning: The version directive and command-line setting no longer provide compatibility with most rendering bugs in versions prior to POV-Ray 3.5. However, compatibility with the scene language is provided for scenes as old as POV-Ray 1.0 just as in all previous versions of POV-Ray. Nevertheless, we strongly recommend you update scenes at least to POV-Ray 3.5 syntax if you plan to use them in future versions of POV-Ray.