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- POV-Ray Tutorial
- Conditional
Statements
Branching
#if(...)... #else ... #end
- in loops
- in macros
- in animations
- turning on/off of parts
#switch(...) #case .. #end
- selection by tables
Check for Existence
#ifdef(...) #ifndef(...)
>Check for include files
- Defaults in include files
Loops
Prechecked, Postchecked,
Count-controlled, Early-Exit
#while(...)... #end
#for(...)... #end
- Samples:
- Loops with POV-Ray
- Loops, Sine, Cosine
- Random with POV-Ray
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Check for Existance - Check if an Include File is loaded
Two examples for the use of "#ifndef" with include files:
1. Avoiding multiple loading of an include file:
By declaring an according globalen variable in each include file,
(here: MyIncludeFile_Inc_Temp, if the include file name is MyIncludeFile.inc)
we can check by "#ifndef" if this include file was loaded before. In this case
the hole content can be passed over because its content is already known.
2. Making sure that necessary include files for an include file are loaded and
not will be loaded twice:
The following technique can be used to integrate those include files, which are declaring
an according global variable (MyIncludeFile_Inc_Temp) like explained here above.
In include files which need another include file, by a query on the existens of the according
global variable with "#ifndef", we can achieve that the needed other include file
will be loaded if the scene file didn't load this necessary file before.
In addition this technique avoids a multiple loading of the according include file
if it was loaded befor by the scene file or by other include files.
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Avoiding multiple loading of an include file:
// include file "MyIncludeFile.inc"
#ifndef( MyIncludeFile_inc_Temp )
#declare MyIncludeFile_Inc_Temp = version;
#version 3.5;
//----------------------------------------
body of include file
//----------------------------------------
#version MyIncludeFile_Inc_Temp;
#end // end of "#ifndef( ... )"
//-------------------- end of include file |
Making sure that necessary include files are loaded and
avoiding multiple loading of these include files:
//--------------------------//
#ifndef( Shapes_Inc_Temp)
#include "shapes.inc"
#end
//--------------------------//
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